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

PubMed

Ueda, Yukari; Taira, Zenei

2013-01-01

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 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intestinal absorption process was significantly different among the four calcium salts. The rank of absolute bioavailability of calcium was calcium ascorbate > calcium L-lactate ≥ calcium acetate > calcium chloride. The mean residence time (MRTab) of calcium from calcium ascorbate (32.2 minutes) in the intestinal tract was much longer than that from calcium L-lactate (9.5 minutes), calcium acetate (15.0 minutes) and calcium chloride (13.6 minutes). Furthermore, the foods di-D-fructo-furanose-1,2':2,3'-dianhydride, sudachi (Citrus sudachi) juice, and moromi-su (a Japanese vinegar) increased the absolute bioavailability of calcium from calcium chloride by 2.46-fold, 2.86-fold, and 1.23-fold, respectively, and prolonged MRTab by 48.5 minutes, 43.1 minutes, and 44.9 minutes, respectively. In conclusion, the prolonged MRTab of calcium in the intestinal tract by anion or food might cause the increased absorbability of calcium.

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

PubMed Central

Ueda, Yukari; Taira, Zenei

2013-01-01

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 mg/kg, and is not affected by anions. Results after oral calcium administration of 150 mg/kg showed that the intestinal absorption process was significantly different among the four calcium salts. The rank of absolute bioavailability of calcium was calcium ascorbate > calcium L-lactate ≥ calcium acetate > calcium chloride. The mean residence time (MRTab) of calcium from calcium ascorbate (32.2 minutes) in the intestinal tract was much longer than that from calcium L-lactate (9.5 minutes), calcium acetate (15.0 minutes) and calcium chloride (13.6 minutes). Furthermore, the foods di-D-fructo-furanose-1,2′:2,3′-dianhydride, sudachi (Citrus sudachi) juice, and moromi-su (a Japanese vinegar) increased the absolute bioavailability of calcium from calcium chloride by 2.46-fold, 2.86-fold, and 1.23-fold, respectively, and prolonged MRTab by 48.5 minutes, 43.1 minutes, and 44.9 minutes, respectively. In conclusion, the prolonged MRTab of calcium in the intestinal tract by anion or food might cause the increased absorbability of calcium. PMID:27186137

Visualisation of an nsPEF induced calcium wave using the genetically encoded calcium indicator GCaMP in U87 human glioblastoma cells.

PubMed

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

2018-02-01

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.

75 FR 7566 - Saccharin from the People's Republic of China: Final Results of Changed Circumstances Review

Federal Register 2010, 2011, 2012, 2013, 2014

2010-02-22

...- 1778 and (202) 482-0650, respectively. SUPPLEMENTARY INFORMATION: Background On July 9, 2003, the...'') Registry 128-44-9); (2) calcium saccharin (CAS Registry 6485-34-3); (3) acid (or insoluble) saccharin (CAS... saccharin from the PRC are sodium and calcium saccharin, which are available in granular, powder, spray...

75 FR 43146 - Saccharin From the People's Republic of China: Final Results of the 2008-2009 Antidumping Duty...

Federal Register 2010, 2011, 2012, 2013, 2014

2010-07-23

.... SUPPLEMENTARY INFORMATION: Background On March 22, 2010, the Department published its Preliminary Results of the... Society Chemical Abstract Service (``CAS'') Registry 128-44-9); (2) calcium saccharin (CAS Registry 6485.... Most of the U.S.-produced and imported grades of saccharin from the PRC are sodium and calcium...

The isotopic composition of cosmic ray calcium

NASA Technical Reports Server (NTRS)

Krombel, K. E.; Wiedenbeck, M. E.

1985-01-01

Data from the high energy cosmic ray experiment on the international sun earth explorer 3 (ISEE-3) spacecraft have been used to study the isotopic composition of cosmic ray calcium at an energy of approx. 260 MeV/amu. The arriving calcium is found to consist of (32 + or - 6)%. A propagation model consistent with both the light and the subiron secondary element abundances was used for the interpretation of the observed calcium composition. The measured 42Ca+43Ca+44Ca abundance is consistent with the calculated secondary production, while the 40Ca abundance implies a source ratio of 40Ca/Fe = (7.0 + or - 1.7)%.

The influence of seawater carbonate chemistry, mineralogy, and diagenesis on calcium isotope variations in Lower-Middle Triassic carbonate rocks

DOE PAGES

Lau, Kimberly V.; Maher, Kate; Brown, Shaun T.; ...

2017-11-01

The geological calcium cycle is linked to the geological carbon cycle through the weathering and burial of carbonate rocks. As a result, calcium (Ca) isotope ratios ( 44 Ca/ 40 Ca, expressed as δ 44/40 Ca) can help to constrain ancient carbon cycle dynamics if Ca cycle behavior can be reconstructed. But, the δ 44/40 Ca of carbonate rocks is influenced not only by the δ 44/40 Ca of seawater but also by diagenetic processes and fractionation associated with carbonate precipitation. In this study, we investigate the dominant controls on carbonate δ 44/40 Ca in Upper Permian to Middle Triassicmore » limestones (ca. 253 to 244 Ma) from south China and Turkey. This time interval is ideal for assessing controls on Ca isotope ratios in carbonate rocks because fluctuations in seawater δ 44/40 Ca may be expected based on several large carbon isotope (δ 13 C) excursions ranging from -2 to + 8‰. Parallel negative δ 13 C and δ 44/40 Ca excursions were previously identified across the end-Permian extinction horizon. Here, we find a second negative excursion in δ 44/40 Ca of ~ 0.2‰ within Lower Triassic strata in both south China and Turkey; however, this excursion is not synchronous between regions and thus cannot be interpreted to reflect secular change in the δ 44/40 Ca of global seawater. Additionally, δ 44/40 Ca values from Turkey are consistently 0.3‰ lower than contemporaneous samples from south China, providing further support for local or regional influences. By measuring δ 44/40 Ca and Sr concentrations ([Sr]) in two stratigraphic sections located at opposite margins of the Paleo-Tethys Ocean, we can determine whether the data represent global conditions (e.g., secular variations in the δ 44/40 Ca of seawater) versus local controls (e.g., original mineralogy or diagenetic alteration). The [Sr] and δ 44/40 Ca data from this study are best described statistically by a log-linear correlation that also exists in many previously published datasets of various geological ages. By using a model of early marine diagenetic water-rock interaction, we illustrate that this general correlation can be explained by the chemical evolution of bulk carbonate sediment samples with different initial mineralogical compositions that subsequently underwent recrystallization. Although early diagenetic resetting and carbonate mineralogy strongly influence the carbonate δ 44/40 Ca values, the relationship between [Sr] and δ 44/40 Ca holds potential for reconstructing first-order secular changes in seawater δ 44/40 Ca composition.« less

The influence of seawater carbonate chemistry, mineralogy, and diagenesis on calcium isotope variations in Lower-Middle Triassic carbonate rocks

DOE Office of Scientific and Technical Information (OSTI.GOV)

Lau, Kimberly V.; Maher, Kate; Brown, Shaun T.

The geological calcium cycle is linked to the geological carbon cycle through the weathering and burial of carbonate rocks. As a result, calcium (Ca) isotope ratios ( 44 Ca/ 40 Ca, expressed as δ 44/40 Ca) can help to constrain ancient carbon cycle dynamics if Ca cycle behavior can be reconstructed. But, the δ 44/40 Ca of carbonate rocks is influenced not only by the δ 44/40 Ca of seawater but also by diagenetic processes and fractionation associated with carbonate precipitation. In this study, we investigate the dominant controls on carbonate δ 44/40 Ca in Upper Permian to Middle Triassicmore » limestones (ca. 253 to 244 Ma) from south China and Turkey. This time interval is ideal for assessing controls on Ca isotope ratios in carbonate rocks because fluctuations in seawater δ 44/40 Ca may be expected based on several large carbon isotope (δ 13 C) excursions ranging from -2 to + 8‰. Parallel negative δ 13 C and δ 44/40 Ca excursions were previously identified across the end-Permian extinction horizon. Here, we find a second negative excursion in δ 44/40 Ca of ~ 0.2‰ within Lower Triassic strata in both south China and Turkey; however, this excursion is not synchronous between regions and thus cannot be interpreted to reflect secular change in the δ 44/40 Ca of global seawater. Additionally, δ 44/40 Ca values from Turkey are consistently 0.3‰ lower than contemporaneous samples from south China, providing further support for local or regional influences. By measuring δ 44/40 Ca and Sr concentrations ([Sr]) in two stratigraphic sections located at opposite margins of the Paleo-Tethys Ocean, we can determine whether the data represent global conditions (e.g., secular variations in the δ 44/40 Ca of seawater) versus local controls (e.g., original mineralogy or diagenetic alteration). The [Sr] and δ 44/40 Ca data from this study are best described statistically by a log-linear correlation that also exists in many previously published datasets of various geological ages. By using a model of early marine diagenetic water-rock interaction, we illustrate that this general correlation can be explained by the chemical evolution of bulk carbonate sediment samples with different initial mineralogical compositions that subsequently underwent recrystallization. Although early diagenetic resetting and carbonate mineralogy strongly influence the carbonate δ 44/40 Ca values, the relationship between [Sr] and δ 44/40 Ca holds potential for reconstructing first-order secular changes in seawater δ 44/40 Ca composition.« less

[Prevention of osteoporosis by foods and dietary supplements. Chocolate malt drink MILO: nutrition in children and calcium absorption].

PubMed

Fukushima, Yoichi; Kumagai, Akiko

2006-10-01

Calcium is not sufficiently consumed by Japanese at any age groups. Childhood is an important period, when they should earn bone minerals to reach higher peak bone mass for reducing the risk of osteoporosis in their later life. Children require higher calcium consumption per body weight than adults, and also establish their dietary pattern in this period. MILO has attracted widespread popularity as a good-taste chocolate-flavored malt drink with balanced nutrients for children. We developed FOSHU MILO with fructooligosaccharides (FOS) aiming at improving absorption of calcium, which is originally rich in the products. Using the calcium stable isotope (44)Ca, we found that the urinary excretion in the subject fed the products with FOS was higher than that of control product without FOS, suggesting that the FOSHU MILO is effective in promoting calcium absorption from the intestines. MILO could contribute to bone health by increasing consumption of calcium and/or improving the calcium bioavailability.

Effect of calcium on the hemolytic activity of Stichodactyla helianthus toxin sticholysin II on human erythrocytes.

PubMed

Celedón, Gloria; González, Gustavo; Lissi, Eduardo; Cerda, Tania; Martinez, Diana; Soto, Carmen; Pupo, Mario; Pazos, Fabiola; Lanio, Maria E; Alvarez, Carlos

2009-11-01

Sticholysin II (St II) is a toxin from the sea anemona Stichodactyla helianthus that produces erythrocytes lysis at low concentration and its activity depends on the presence of calcium. Calcium may act modifying toxin interaction with erythrocyte membranes or activating cellular processes which may result in a modified St II lytic action. In this study we are reporting that, in the presence of external K(+), extracellular calcium decreased St II activity on erythrocytes. On the other hand an increase of intracellular calcium promotes Sty II lytic activity. The effect of intracellular calcium was specifically studied in relation to membrane lipid translocation elicited by scramblases and how this action influence St II lytic activity on erythrocytes. We used 0.5 mmol/L calcium and 10 mmol/L A23187, as calcium ionophore, for scramblases activation and found increased St II activity associated to increase of intracellular calcium. N-ethyl maleimide (activator) and 4,4'-diisothiocyanatostilbene-2,2'-disulfonate (inhibitor) were used as scramblases modulators in the assays which produced an increase and a decrease of the calcium effect, respectively. Results reported suggest an improved St II membrane pore-forming capacity promoted by intracellular calcium associated to membrane phospholipids translocation.

ERP44 inhibits human lung cancer cell migration mainly via IP3R2.

PubMed

Huang, Xue; Jin, Meng; Chen, Ying-Xiao; Wang, Jun; Zhai, Kui; Chang, Yan; Yuan, Qi; Yao, Kai-Tai; Ji, Guangju

2016-06-01

Cancer cell migration is involved in tumour metastasis. However, the relationship between calcium signalling and cancer migration is not well elucidated. In this study, we used the human lung adenocarcinoma A549 cell line to examine the role of endoplasmic reticulum protein 44 (ERP44), which has been reported to regulate calcium release inside of the endoplasmic reticulum (ER), in cell migration. We found that the inositol 1,4,5-trisphosphate receptors (IP3Rs/ITPRs) inhibitor 2-APB significantly inhibited A549 cell migration by inhibiting cell polarization and pseudopodium protrusion, which suggests that Ca2+ is necessary for A549 cell migration. Similarly, the overexpression of ERP44 reduced intracellular Ca2+ release via IP3Rs, altered cell morphology and significantly inhibited the migration of A549 cells. These phenomena were primarily dependent on IP3R2 because wound healing in A549 cells with IP3R2 rather than IP3R1 or IP3R3 siRNA was markedly inhibited. Moreover, the overexpression of ERP44 did not affect the migration of the human neuroblastoma cell line SH-SY5Y, which mainly expresses IP3R1. Based on the above observations, we conclude that ERP44 regulates A549 cell migration mainly via an IP3R2-dependent pathway.

ERP44 inhibits human lung cancer cell migration mainly via IP3R2

PubMed Central

Zhai, Kui; Chang, Yan; Yuan, Qi; Yao, Kai-Tai; Ji, Guangju

2016-01-01

Cancer cell migration is involved in tumour metastasis. However, the relationship between calcium signalling and cancer migration is not well elucidated. In this study, we used the human lung adenocarcinoma A549 cell line to examine the role of endoplasmic reticulum protein 44 (ERP44), which has been reported to regulate calcium release inside of the endoplasmic reticulum (ER), in cell migration. We found that the inositol 1,4,5-trisphosphate receptors (IP3Rs/ITPRs) inhibitor 2-APB significantly inhibited A549 cell migration by inhibiting cell polarization and pseudopodium protrusion, which suggests that Ca2+ is necessary for A549 cell migration. Similarly, the overexpression of ERP44 reduced intracellular Ca2+ release via IP3Rs, altered cell morphology and significantly inhibited the migration of A549 cells. These phenomena were primarily dependent on IP3R2 because wound healing in A549 cells with IP3R2 rather than IP3R1 or IP3R3 siRNA was markedly inhibited. Moreover, the overexpression of ERP44 did not affect the migration of the human neuroblastoma cell line SH-SY5Y, which mainly expresses IP3R1. Based on the above observations, we conclude that ERP44 regulates A549 cell migration mainly via an IP3R2-dependent pathway. PMID:27347718

Increased calcium absorption from synthetic stable amorphous calcium carbonate: double-blind randomized crossover clinical trial in postmenopausal women.

PubMed

Vaisman, Nachum; Shaltiel, Galit; Daniely, Michal; Meiron, Oren E; Shechter, Assaf; Abrams, Steven A; Niv, Eva; Shapira, Yami; Sagi, Amir

2014-10-01

Calcium supplementation is a widely recognized strategy for achieving adequate calcium intake. We designed this blinded, randomized, crossover interventional trial to compare the bioavailability of a new stable synthetic amorphous calcium carbonate (ACC) with that of crystalline calcium carbonate (CCC) using the dual stable isotope technique. The study was conducted in the Unit of Clinical Nutrition, Tel Aviv Sourasky Medical Center, Israel. The study population included 15 early postmenopausal women aged 54.9 ± 2.8 (mean ± SD) years with no history of major medical illness or metabolic bone disorder, excess calcium intake, or vitamin D deficiency. Standardized breakfast was followed by randomly provided CCC or ACC capsules containing 192 mg elemental calcium labeled with 44Ca at intervals of at least 3 weeks. After swallowing the capsules, intravenous CaCl2 labeled with 42Ca on was administered on each occasion. Fractional calcium absorption (FCA) of ACC and CCC was calculated from the 24-hour urine collection following calcium administration. The results indicated that FCA of ACC was doubled (± 0.96 SD) on average compared to that of CCC (p < 0.02). The higher absorption of the synthetic stable ACC may serve as a more efficacious way of calcium supplementation. © 2014 American Society for Bone and Mineral Research.

CT Coronary Angiography vs. Coronary Artery Calcium Scoring for the Occupational Assessment of Military Aircrew.

PubMed

Parsons, Iain; Pavitt, Chris; Chamley, Rebecca; d'Arcy, Jo; Nicol, Ed

2017-02-01

To ensure flight safety military aircrew undergo regular clinical and occupational assessment. Coronary artery calcium scoring (CACS) has been established as an imaging modality to noninvasively assess coronary artery disease (CAD). CT coronary angiography (CTCA) potentially offers a more accurate assessment of CAD, but has not been formally assessed in military aircrew. This retrospective cohort study is designed to compare the theoretical differences in downstream investigations and occupational outcomes in aircrew with suspected CAD comparing CTCA with existing CACS pathways. A 2-yr retrospective cohort study of consecutive UK military patients who underwent a CTCA and CACS was undertaken. Patient demographics, CTCA and CACS results, and initial and final occupational restrictions were analyzed comparing current UK, Canadian, and U.S. pathways. There were 44 patients who underwent CACS and CTCA. The commonest indication for a CTCA was a positive exercise ECG. Increasing CACS, stenosis severity, and stenosis burden were associated with significantly greater likelihood of occupational restriction (P = < 0.01). Following CTCA, 26/44 (59%) patients were found to have evidence of CAD, with 13/44 (30%) having at least a single vessel stenosis ≥50%. All of these patients had subsequent occupational restrictions. Two patients with a calcium score ≤10 had at least 1 single vessel stenosis ≥50%. A CTCA pathway is potentially a better discriminator of CAD burden in aircrew when compared with CACS and may reduce downstream testing, allowing a more efficacious approach to CAD assessment in military aircrew.Parsons I, Pavitt C, Chamley R, d'Arcy J, Nicol E. CT coronary angiography vs. coronary artery calcium scoring for the occupational assessment of military aircrew. Aerosp Med Hum Perform. 2017; 88(2):76-81.

The influence of calcium supplementation on substrate metabolism during exercise in humans: a randomized controlled trial.

PubMed

Gonzalez, J T; Green, B P; Campbell, M D; Rumbold, P L S; Stevenson, E J

2014-06-01

High calcium intakes enhance fat loss under restricted energy intake. Mechanisms explaining this may involve reduced dietary fat absorption, enhanced lipid utilization and (or) reductions in appetite. This study aimed to assess the impact of 2 weeks of calcium supplementation on substrate utilization during exercise and appetite sensations at rest. Thirteen physically active males completed two 14-d supplemental periods, in a double-blind, randomized crossover design separated by a ⩾4-week washout period. During supplementation, a test-drink was consumed daily containing 400 and 1400 mg of calcium during control (CON) and high-calcium (CAL) periods, respectively. Cycling-based exercise tests were conducted before and after each supplemental period to determine substrate utilization rates and circulating metabolic markers (non-esterified fatty acid, glycerol, glucose and lactate concentrations) across a range of exercise intensities. Visual analog scales were completed in the fasting, rested state to determine subjective appetite sensations. No significant differences between supplements were observed in lipid or carbohydrate utilization rates, nor in circulating metabolic markers (both P>0.05). Maximum rates of lipid utilization were 0.47±0.05 and 0.44±0.05 g/min for CON and CAL, respectively, prior to supplementation and 0.44±0.05 and 0.42±0.05 g/min, respectively, post-supplementation (main effects of time, supplement and time x supplement interaction effect all P>0.05). Furthermore, no significant differences were detected in any subjective appetite sensations (all P>0.05). Two weeks of calcium supplementation does not influence substrate utilization during exercise in physically active males.

Calcium isotopic composition of mantle xenoliths and minerals from Eastern China

NASA Astrophysics Data System (ADS)

Kang, Jin-Ting; Zhu, Hong-Li; Liu, Yu-Fei; Liu, Fang; Wu, Fei; Hao, Yan-Tao; Zhi, Xia-Chen; Zhang, Zhao-Feng; Huang, Fang

2016-02-01

This study presents calcium isotope data for co-existing clinopyroxenes (cpx), orthopyroxenes (opx), and olivine (ol) in mantle xenoliths to investigate Ca isotopic fractionation in the upper mantle. δ44/40Ca (δ44/40Ca (‰) = (44Ca/40Ca)SAMPLE/(44Ca/40Ca)SRM915a - 1) in opx varies from 0.95 ± 0.05‰ to 1.82 ± 0.01‰ and cpx from 0.71 ± 0.06‰ to 1.03 ± 0.12‰ (2se). δ44/40Ca in ol (P-15) is 1.16 ± 0.08‰, identical to δ44/40Ca of the co-existing opx (1.12 ± 0.09‰, 2se). The Δ44/40Caopx-cpx (Δ44/40Caopx-cpx = δ44/40Caopx-δ44/40Cacpx) shows a large variation ranging from -0.01‰ to 1.11‰ and it dramatically increases with decreasing of Ca/Mg (atomic ratio) in opx. These observations may reflect the effect of opx composition on the inter-mineral equilibrium fractionation of Ca isotopes, consistent with the theoretical prediction by first-principles theory calculations (Feng et al., 2014). Furthermore, Δ44/40Caopx-cpx decreases when temperature slightly increases from 1196 to 1267 K. However, the magnitude of such inter-mineral isotopic fractionation (1.12‰) is not consistent with the value calculated by the well-known correlation between inter-mineral isotope fractionation factors and 1/T2 (Urey, 1947). Instead, it may reflect the temperature control on crystal chemistry of opx (i.e., Ca content), which further affects Δ44/40Caopx-cpx. The calculated δ44/40Ca of bulk peridotites and pyroxenites range from 0.76 ± 0.06‰ to 1.04 ± 0.12‰ (2se). Notably, δ44/40Ca of bulk peridotites are positively correlated with CaO and negatively with MgO content. Such correlations can be explained by mixing between a fertile mantle end-member and a depleted one with low δ44/40Ca, indicating that Ca isotopes could be a useful tool in studying mantle evolution.

Impedance and dielectric relaxation spectroscopy studies on the calcium modified Na0.5Bi0.44Ca0.06TiO2.97 ceramics

NASA Astrophysics Data System (ADS)

Wang, W. G.; Li, X. Y.

2017-12-01

Na0.5Bi0.44Ca0.06TiO2.97 ceramics were synthetized by conventional solid-state reaction. XRD measurement analysis shows that the Na0.5Bi0.44Ca0.06TiO2.97 sample is the single perovskite structures. The oxide ion conductivity of the Na0.5Bi0.44Ca0.06TiO2.97 sample was investigated by AC impedance spectroscopy measurement. The bulk conductivity of Na0.5Bi0.44Ca0.06TiO2.97 sample can arrive at 2.22×10-4 S/cm at 573 K in air atmosphere. By changing measuring temperature of dielectric frequency spectroscopy measurement, the activation energy E and pre-exponential factor τ0 are E= 0.81 eV, τ0=1.5×10-13 s for Na0.5Bi0.44Ca0.06TiO2.97 sample, respectively. Judging from the relaxation parameters, the dielectric loss peaks correspond to oxide ion via vacancies diffusion in Na0.5Bi0.44Ca0.06TiO2.97 sample. Compared with the same dopant amount Na0.5Bi0.5Ti0.94Mg0.06O2.94 compound, the better oxygen vacancy mobility and larger specific free volume Vsf might be responsible for the favourable oxide ion conductivity in the Na0.5Bi0.44Ca0.06TiO2.97 sample, indicating that calcium modified Na0.5Bi0.5TiO3 materials are promising for intermediate-temperature solid electrochemical devices.

Does Lactation Mitigate Triple Negative/Basal Breast Cancer Progression

DTIC Science & Technology

2013-11-01

protein; calponin, a calcium binding cytoskeletal protein [41-43]; and the transcription factor p63, a putative tumor suppressor [8, 12, 44], to...development of wound-induced tumors in chickens infected with Rous sarcoma virus. Cancer Res 1994, 54(16):4334-4341. 31. Stuelten CH, Barbul A, Busch JI...gizzard calponin. Interactions of the 145-163 region with F-actin, calcium -binding proteins, and tropomyosin. J Biol Chem 1995, 270(15):8867-8876. 51

Quantitative Mineralogical Composition of Calculi and Urine Abnormalities for Calcium Oxalate Stone Formers: A Single-Center Results.

PubMed

Kustov, Andrey V; Strelnikov, Alexander I

2018-05-03

The paper focuses on the relationship of risk factors and metabolic disorders with mineralogical composition of calculi, age and gender of calcium oxalate stone formers. Stone mineralogical composition, 24 hour biochemistry and pH-profile of urine were examined for sixty four stone formers using powder X-ray diffraction, spectrophotometric and potentiometric techniques. The analysis indicated that 44 % of calculi were composed of pure calcium oxalate monohydrate, whereas other 56 % contained both monohydrate and dihydrate or usually their mixtures with hydroxyl apatite. Hypocitraturia, hypercalciuria and hyperuricosuria were identified as the most frequent disorders. Patients with pure calcium oxalate stones and calcium oxalate mixed with apatite revealed different patterns including age, acid-base balance of urine, calcium, citrate excretion etc.Conclusions: Our results demonstrate that most patients simultaneously reveal several risk factors. The special attention should be paid to normalize the daily citrate, calcium and urate excretion. High risk patients, such as postmenopausal females or stone formers with a high apatite content require a specific metabolic evaluation towards in highlighting abnormalities associated with stone formation.

Dietary fat and not calcium supplementation or dairy product consumption is associated with changes in anthropometrics during a randomized, placebo-controlled energy-restriction trial.

PubMed

Smilowitz, Jennifer T; Wiest, Michelle M; Teegarden, Dorothy; Zemel, Michael B; German, J Bruce; Van Loan, Marta D

2011-10-05

Insufficient calcium intake has been proposed to cause unbalanced energy partitioning leading to obesity. However, weight loss interventions including dietary calcium or dairy product consumption have not reported changes in lipid metabolism measured by the plasma lipidome. The objective of this study was to determine the relationships between dairy product or supplemental calcium intake with changes in the plasma lipidome and body composition during energy restriction. A secondary objective of this study was to explore the relationships among calculated macronutrient composition of the energy restricted diet to changes in the plasma lipidome, and body composition during energy restriction. Overweight adults (n = 61) were randomized into one of three intervention groups including a deficit of 500kcal/d: 1) placebo; 2) 900 mg/d calcium supplement; and 3) 3-4 servings of dairy products/d plus a placebo supplement. Plasma fatty acid methyl esters of cholesterol ester, diacylglycerol, free fatty acids, lysophosphatidylcholine, phosphatidylcholine, phosphatidylethanolamine and triacylglycerol were quantified by capillary gas chromatography. After adjustments for energy and protein (g/d) intake, there was no significant effect of treatment on changes in weight, waist circumference or body composition. Plasma lipidome did not differ among dietary treatment groups. Stepwise regression identified correlations between reported intake of monounsaturated fat (% of energy) and changes in % lean mass (r = -0.44, P < 0.01) and % body fat (r = 0.48, P < 0.001). Polyunsaturated fat intake was associated with the % change in waist circumference (r = 0.44, P < 0.01). Dietary saturated fat was not associated with any changes in anthropometrics or the plasma lipidome. Dairy product consumption or calcium supplementation during energy restriction over the course of 12 weeks did not affect plasma lipids. Independent of calcium and dairy product consumption, short-term energy restriction altered body composition. Reported dietary fat composition of energy restricted diets was associated with the degree of change in body composition in these overweight and obese individuals.

Interpreting the Marine Calcium Isotope Record: Influence of Reef Builders

NASA Astrophysics Data System (ADS)

Boehm, F.; Eisenhauer, A.; Farkas, J.; Kiessling, W.; Veizer, J.; Wallmann, K.

2008-12-01

The calcium isotopic composition of seawater as recorded in brachiopod shells varied substantially during the Paleozoic (Farkas et al. 2007, Geochim. Cosmochim. Acta, 71, 5117-5134). The most prominent feature of the record is an excursion to higher 44Ca/40Ca values that started during the Early Carboniferous and lasted until the Permian. The shift occurred shortly after the transition from a calcite-sea to an aragonite-sea (Sandberg 1983, Nature 305, 19-22; Stanley and Hardie 1998, Pal3, 144, 3-19). It therefore has been interpreted to reflect a change in the average calcium isotope fractionation of carbonates produced in the oceans. Aragonite is depleted by about 0.6 permil in 44Ca/40Ca compared to calcite (Gussone et al. 2005, Geochim. Cosmochim. Acta, 69, 4485-4494). Consequently a transient shift from calcite dominated to an aragonite dominated calcium carbonate sedimentation could have caused the observed 0.5 permil isotope shift. We compare the marine calcium isotope record with a new compilation of the Phanerozoic trends in the skeletal mineralogy of marine invertebrates (Kiessling et al. 2008, Nature Geoscience, 1, 527-530). The compilation is based on data collected in the PaleoReef database and the Paleobiology Database, which include information on Phanerozoic reef complexes and taxonomic collection data of Phanerozoic biota, respectively. We find a strong positive correlation between the calcium isotope ratios and the abundance of aragonitic reef builders from the Silurian until the Permian at a sample resolution of about 10 million years. The two records, however, diverge in the Triassic, when reefs were dominated by aragonite but the calcium isotope values remained at a relatively low level. We also find a good correlation between calcium isotopes and the proportion of aragonite in the general record of Phanerozoic biota. However, in this case the records start to diverge already in the latest Carboniferous. The observations suggest that the Paleozoic calcium isotope record was indeed strongly controlled by the skeletal mineralogy of the major carbonate producers. The collapse of the correlation in the late Paleozoic points to the evolution of new biocalcification mechanisms that allowed a more strict biological control of the calcium fluxes in the calcifying biota (sensu Gussone et al. 2006, Geology, 34, 625-628).

Ionotropic and Metabotropic Mechanisms of Allosteric Modulation of α7 Nicotinic Receptor Intracellular Calcium.

PubMed

King, Justin R; Ullah, Aman; Bak, Ellen; Jafri, M Saleet; Kabbani, Nadine

2018-06-01

The pharmacological targeting of the α 7 nicotinic acetylcholine receptor ( α 7) is a promising strategy in the development of new drugs for neurologic diseases. Because α 7 receptors regulate cellular calcium, we investigated how the prototypical type II-positive allosteric modulator PNU120596 affects α 7-mediated calcium signaling. Live imaging experiments show that PNU120596 augments ryanodine receptor-driven calcium-induced calcium release (CICR), inositol-induced calcium release (IICR), and phospholipase C activation by the α 7 receptor. Both influx of calcium through the α 7 nicotinic acetylcholine receptor (nAChR) channel as well as the binding of intracellular G proteins were involved in the effect of PNU120596 on intracellular calcium. This is evidenced by the findings that chelation of extracellular calcium, expression of α 7 D44A or α 7 345-348A mutant subunits, or blockade of calcium store release compromised the ability of PNU120596 to increase intracellular calcium transients generated by α 7 ligand activation. Spatiotemporal stochastic modeling of calcium transient responses corroborates these results and indicates that α 7 receptor activation enables calcium microdomains locally and to lesser extent in the distant cytosol. From the model, allosteric modulation of the receptor activates CICR locally via ryanodine receptors and augments IICR through enhanced calcium influx due to prolonged α 7 nAChR opening. These findings provide a new mechanistic framework for understanding the effect of α 7 receptor allosteric modulation on both local and global calcium dynamics. Copyright © 2018 by The American Society for Pharmacology and Experimental Therapeutics.

Demographic, dietary, and urinary factors and 24-h urinary calcium excretion.

PubMed

Taylor, Eric N; Curhan, Gary C

2009-12-01

Higher urinary calcium is a risk factor for nephrolithiasis. This study delineated associations between demographic, dietary, and urinary factors and 24-h urinary calcium. Cross-sectional studies were conducted of 2201 stone formers (SF) and 1167 nonstone formers (NSF) in the Health Professionals Follow-up Study (men) and Nurses' Health Studies I and II (older and younger women). Median urinary calcium was 182 mg/d in men, 182 mg/d in older women, and 192 mg/d in younger women. Compared with NSF, urinary calcium as a fraction of calcium intake was 33 to 38% higher in SF (P values < or =0.01). In regression analyses, participants were combined because associations with urinary calcium were similar in each cohort and in SF and NSF. After multivariate adjustment, participants in the highest quartile of calcium intake excreted 18 mg/d more urinary calcium than those in the lowest (P trend =0.01). Caffeine and family history of nephrolithiasis were positively associated, whereas urinary potassium, thiazides, gout, and age were inversely associated, with urinary calcium. After multivariate adjustment, participants in the highest quartiles of urinary magnesium, sodium, sulfate, citrate, phosphorus, and volume excreted 71 mg/d, 37 mg/d, 44 mg/d, 61 mg/d, 37 mg/d, and 24 mg/d more urinary calcium, respectively, than participants in the lowest (P values trend < or =0.01). Intestinal calcium absorption and/or negative calcium balance is greater in SF than NSF. Higher calcium intakes at levels typically observed in free-living individuals are associated with only small increases in urinary calcium.

Engineered Metal-Phenolic Capsules Show Tunable Targeted Delivery to Cancer Cells.

PubMed

Ju, Yi; Cui, Jiwei; Sun, Huanli; Müllner, Markus; Dai, Yunlu; Guo, Junling; Bertleff-Zieschang, Nadja; Suma, Tomoya; Richardson, Joseph J; Caruso, Frank

2016-06-13

We engineered metal-phenolic capsules with both high targeting and low nonspecific cell binding properties. The capsules were prepared by coating phenolic-functionalized hyaluronic acid (HA) and poly(ethylene glycol) (PEG) on calcium carbonate templates, followed by cross-linking the phenolic groups with metal ions and removing the templates. The incorporation of HA significantly enhanced binding and association with a CD44 overexpressing (CD44+) cancer cell line, while the incorporation of PEG reduced nonspecific interactions with a CD44 minimal-expressing (CD44-) cell line. Moreover, high specific targeting to CD44+ cells can be balanced with low nonspecific binding to CD44- cells simply by using an optimized feed-ratio of HA and PEG to vary the content of HA and PEG incorporated into the capsules. Loading an anticancer drug (i.e., doxorubicin) into the obtained capsules resulted in significantly higher cytotoxicity to CD44+ cells but lower cytotoxicity to CD44- cells.

Vitamin D treatment in calcium-deficiency rickets: a randomised controlled trial.

PubMed

Thacher, Tom D; Fischer, Philip R; Pettifor, John M

2014-09-01

To determine whether children with calcium-deficiency rickets have a better response to treatment with vitamin D and calcium than with calcium alone. Randomised controlled trial. Jos University Teaching Hospital, Jos, Nigeria. Nigerian children with active rickets treated with calcium carbonate as limestone (approximately 938 mg elemental calcium twice daily) were, in addition, randomised to receive either oral vitamin D2 50,000 IU (Ca+D, n=44) or placebo (Ca, n=28) monthly for 24 weeks. Achievement of a 10-point radiographic severity score ≤1.5 and serum alkaline phosphatase ≤350 U/L. The median (range) age of enrolled children was 46 (15-102) months, and baseline characteristics were similar in the two groups. Mean (±SD) 25-hydroxyvitamin D (25(OH)D) was 30.2±13.2 nmol/L at baseline, and 29 (43%) had values <30 nmol/L. Baseline alkaline phosphatase and radiographic scores were unrelated to vitamin D status. Of the 68 children (94% of original cohort) who completed 24 weeks of treatment, 29 (67%) in the Ca+D group and 11 (44%) in the Ca group achieved the primary outcome (p=0.06). Baseline 25(OH)D did not alter treatment group effects (p=0.99 for interaction). At the end of 24 weeks, 25(OH)D values were 55.4±17.0 nmol/L and 37.9±20.0 nmol/L in the Ca+D and Ca groups, respectively, (p<0.001). In the Ca+D and Ca groups, the final 25(OH)D concentration was greater in those who achieved the primary outcome (56.4±17.2 nmol/L) than in those who did not (37.7±18.5 nmol/L, p<0.001). In children with calcium-deficiency rickets, there is a trend for vitamin D to improve the response to treatment with calcium carbonate as limestone, independent of baseline 25(OH)D concentrations. ClinicalTrials.gov NCT00949832. Published by the BMJ Publishing Group Limited. For permission to use (where not already granted under a licence) please go to http://group.bmj.com/group/rights-licensing/permissions.

Constraining the cause of the end-Guadalupian extinction with coupled records of carbon and calcium isotopes

NASA Astrophysics Data System (ADS)

Jost, A. B.; Mundil, R.; He, B.; Brown, S. T.; Altiner, D.; Sun, Y.; DePaolo, D. J.; Payne, J.

2013-12-01

A negative δ13C excursion in carbonate sediments from Guadalupian (Middle Permian) and Lopingian (Late Permian) stratigraphic sections has been interpreted to result from a large carbon cycle disturbance during end-Guadalupian extinction event (ca. 260 Ma). However, the carbon isotope data alone are insufficient to uniquely determine the type and magnitude of perturbations to the global carbon cycle. The carbon and calcium cycles are coupled via CaCO3 burial, so changes in calcium isotopes can be used to constrain the cause of a carbon isotope excursion. In this study, we present coupled carbon and calcium isotope records from three Guadalupian-Lopingian (G/L) sections in China and Turkey. Isotope records among our studied sections are inconsistent in both their δ13C and δ44/40Ca records. Similar inconsistencies in δ13C among sections occur across previously published datasets. Sections with large (>3‰) changes in δ13C either show evidence for diagenetic alteration or do not show δ13C and δ44/40Ca changes consistent with severe volcanic degassing from Emeishan or methane clathrate destabilization. We conclude that the large isotopic changes are more likely the result of local burial conditions or diagenetic effects, rather than a large carbon cycle disturbance. Perturbations to the global carbon and calcium cycles appear to have been much smaller across the G/L transition than across the subsequent Permian-Triassic boundary. This finding is consistent with recent paleobiological data showing that the end-Guadalupian extinction was much less severe than previously believed, and was indistinguishable in magnitude from background intervals. However, selective extinction of marine animals with passive respiratory physiology indicates that the G/L extinction cannot simply be due to background extinction or sampling failure, and that it was triggered by some environmental event. Therefore, any environmental event must have been small enough to not generate large changes in δ13C and δ44/40Ca. A small acidification or warming event is therefore plausible, but difficult to confirm. Loss of marine habitat by way of sea-level change also remains a possible extinction trigger.

Synthesis of 3-Methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-One: How to Avoid O-Acylation

ERIC Educational Resources Information Center

Kurteva, Vanya B.; Petrova, Maria A.

2015-01-01

In this laboratory experiment, students synthesize 3-methyl-4-(4-methylbenzoyl)-1-phenyl-pyrazol-5-one by selective C-acylation of 3-methyl-1-phenyl-1H-pyrazol-5-one. Calcium hydroxide is used to push the tautomeric equilibrium toward the enol form, to protect the hydroxyl functionality as a complex, to trap the liberated hydrogen chloride, and to…

Clonorcis sinensis eggs are associated with calcium carbonate gallbladder stones.

PubMed

Qiao, Tie; Ma, Rui-hong; Luo, Zhen-liang; Yang, Liu-qing; Luo, Xiao-bing; Zheng, Pei-ming

2014-10-01

Calcium carbonate gallbladder stones were easily neglected because they were previously reported as a rare stone type in adults. The aim of this study was to investigate the relationship between calcium carbonate stones and Clonorchis sinensis infection. A total of 598 gallbladder stones were studied. The stone types were identified by FTIR spectroscopy. The C. sinensis eggs and DNA were detected by microscopic examination and real-time fluorescent PCR respectively. And then, some egg-positive stones were randomly selected for further SEM examination. Corresponding clinical characteristics of patients with different types of stones were also statistically analyzed. The detection rate of C. sinensis eggs in calcium carbonate stone, pigment stone, mixed stone and cholesterol stone types, as well as other stone types was 60%, 44%, 36%, 6% and 30%, respectively, which was highest in calcium carbonate stone yet lowest in cholesterol stone. A total of 182 stones were egg-positive, 67 (37%) of which were calcium carbonate stones. The C. sinensis eggs were found adherent to calcium carbonate crystals by both light microscopy and scanning electron microscopy. Patients with calcium carbonate stones were mainly male between the ages of 30 and 60, the CO2 combining power of patients with calcium carbonate stones were higher than those with cholesterol stones. Calcium carbonate gallbladder stones are not rare, the formation of which may be associated with C. sinensis infection. Copyright © 2014 Elsevier B.V. All rights reserved.

Calcium-41 as a long-term biological tracer for bone resorption

NASA Astrophysics Data System (ADS)

Elmore, David; Bhattacharyya, Maryka H.; Sacco-Gibson, Nancy; Peterson, David P.

1990-12-01

The use of 41Ca (half-life 1 × 10 5 yr) as a tracer for studying calcium metabolism in living systems is compared to the shorter-lived radionuclides 45Ca (165 d) and 47Ca (45 d) and the stable isotopes 42Ca and 44Ca. The feasibility of using accelerator mass spectrometry (AMS) measurements of 41Ca for studying multi-year calcium resorption in humans was tested as part of a companion study that used 45Ca to measure the effects of dietary cadmium on calcium metabolism in dogs. It was shown that Ca resorbed from prelabeled bones correlates well with 45Ca for a period of 28 weeks. The advantage of 41Ca is that, even with a negligible radiation dose, it can be measured by AMS long after the 45Ca becomes unmeasurable.

Demographic, Dietary, and Urinary Factors and 24-h Urinary Calcium Excretion

PubMed Central

Curhan, Gary C.

2009-01-01

Background and objectives: Higher urinary calcium is a risk factor for nephrolithiasis. This study delineated associations between demographic, dietary, and urinary factors and 24-h urinary calcium. Design, setting, participants, & measurements: Cross-sectional studies were conducted of 2201 stone formers (SF) and 1167 nonstone formers (NSF) in the Health Professionals Follow-up Study (men) and Nurses' Health Studies I and II (older and younger women). Results: Median urinary calcium was 182 mg/d in men, 182 mg/d in older women, and 192 mg/d in younger women. Compared with NSF, urinary calcium as a fraction of calcium intake was 33 to 38% higher in SF (P values ≤0.01). In regression analyses, participants were combined because associations with urinary calcium were similar in each cohort and in SF and NSF. After multivariate adjustment, participants in the highest quartile of calcium intake excreted 18 mg/d more urinary calcium than those in the lowest (P trend =0.01). Caffeine and family history of nephrolithiasis were positively associated, whereas urinary potassium, thiazides, gout, and age were inversely associated, with urinary calcium. After multivariate adjustment, participants in the highest quartiles of urinary magnesium, sodium, sulfate, citrate, phosphorus, and volume excreted 71 mg/d, 37 mg/d, 44 mg/d, 61 mg/d, 37 mg/d, and 24 mg/d more urinary calcium, respectively, than participants in the lowest (P values trend ≤0.01). Conclusions: Intestinal calcium absorption and/or negative calcium balance is greater in SF than NSF. Higher calcium intakes at levels typically observed in free-living individuals are associated with only small increases in urinary calcium. PMID:19820135

Role of calcium-depositing bacteria Agrobacterium tumefaciens and its influence on corrosion of different engineering metals used in cooling water system.

PubMed

Narenkumar, Jayaraman; Sathishkumar, Kuppusamy; Selvi, Adikesavan; Gobinath, Rajagopalan; Murugan, Kadarkarai; Rajasekar, Aruliah

2017-12-01

The present investigation deals with the role of calcium-depositing bacterial community on corrosion of various engineering metals, namely, brass alloy (BS), copper (Cu), stainless steel (SS) and mild steel (MS). Based on the corrosion behavior, Agrobacterium tumefaciens EN13, an aerobic bacterium is identified as calcium-depositing bacteria on engineering metals. The results of the study are supported with biochemical characterization, 16S rRNA gene sequencing, calcium quantification, weight loss, electrochemical (impedance and polarization) and surface analysis (XRD and FTIR) studies. The calcium quantification study showed carbonate precipitation in abiotic system/biotic system as 50 and 700 ppm, respectively. FTIR results too confirmed the accumulation of calcium deposits from the environment on the metal surface by EN13. Electrochemical studies too supported the corrosion mechanism by showing a significant increase in the charge transfer resistance ( R ct ) of abiotic system (44, 33.6, 45, 29.6 Ω cm 2 ) than compared to biotic system (41, 10.1 29 and 25 Ω cm 2 ). Hence, the outcome of the present study confirmed the enhanced bioaccumulation behavior of calcium by the strain, EN13.

Randomised controlled trial of a synthetic triglyceride milk formula for preterm infants

PubMed Central

Lucas, A; Quinlan, P; Abrams, S; Ryan, S; Meah, S; Lucas, P

1997-01-01

AIMS—To test whether use of infant formula containing synthetic structured triglycerides results in: (i) increased palmitate absorption; (ii) increased total fat absorption; (iii) reduction in calcium soap formation in the gut; and hence (iv) increased calcium absorption.
METHODS—A randomised study was made of 24 infants comparing three formulas, one containing the synthetic fat Betapol with 74% of palmitate in the 2-position, which was substantially higher than in the two comparison diets (8.4% and 28%). The hypothesised outcomes were tested using balance studies, detailed chemical analysis of stool specimens and dual calcium isotope tracers (44calcium orally and 46calcium intravenously). 
RESULTS—Three of the four hypotheses were confirmed: use of a formula rich in 2-position palmitate (i) improved palmitate (16:0) and also (18:0) absorption; (ii) reduced the formation of insoluble calcium soaps in the stool; and (iii) improved calcium absorption, determined by the dual tracer technique from 42 (SE 3)% to 57 (7)%.
CONCLUSION—Synthetic triglycerides that mimic the stereoisometric structure of those in breast milk may have a valuable role in the design of formulas used for preterm infants in neonatal intensive care units.

 PMID:9462186

Vitamin D status did not related to calcium status in active tuberculosis patients in North Sumatera, Indonesia

NASA Astrophysics Data System (ADS)

Keumala Sari, Dina; Khairina Arrasyid, Nurfida

2018-03-01

Background: Tuberculosis is one of the highest mortality caused in a tropical country with abundant sunlight such Indonesia. Vitamin D and calcium plays important roles in tuberculosis pathogenesis. Objective:We sought to determine whether there is an association between vitamin D status and calcium status in tuberculosis patients. Design: We conducted a cross-sectional study of 32 man and women aged 18-60 years with active tuberculosis in North Sumatera, Indonesia. Parameters were 25(OH)D and calcium serum level, body mass index, fat mass, and others lifestyles factors also assessed. The association was analysis using chi-square or fischer test. Results: the mean of study subjects age were 37.2±14.9 years old and BMI were 20.8±4.4 kg/m2 There were 81.2% subjects categorized into vitamin D deficiency-insufficiency and 18.8% categorized into vitamin D sufficiency. There were 29% subjects categorized into normal calcium level, and 3% were hypocalcemia. Based on food recall analysis, there were found lower vitamin D and calcium intake. There is no association between vitamin D and calcium classification. Conclusions: based on this result, although there is no association between vitamin D and calcium, but there could be altered by lower food intake and tuberculosis progression.

Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements.

PubMed

Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

2018-01-13

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter ( n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA ( p < 0.05) while maximum calcium ion release was dependent on Vol of TSC ( p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution ( p < 0.05).

Effect of Exposed Surface Area, Volume and Environmental pH on the Calcium Ion Release of Three Commercially Available Tricalcium Silicate Based Dental Cements

PubMed Central

Rajasekharan, Sivaprakash; Vercruysse, Chris; Martens, Luc; Verbeeck, Ronald

2018-01-01

Tricalcium silicate cements (TSC) are used in dental traumatology and endodontics for their bioactivity which is mostly attributed to formation of calcium hydroxide during TSC hydration and its subsequent release of calcium and hydroxide ions. The aim of this study was to determine the effect of volume (Vol), exposed surface area (ESA) and pH of surrounding medium on calcium ion release. Three commercially available hydraulic alkaline dental cements were mixed and condensed into cylindrical tubes of varying length and diameter (n = 6/group). For the effect of ESA and Vol, tubes were immersed in 10 mL of deionized water. To analyze the effect of environmental pH, the tubes were randomly immersed in 10 mL of buffer solutions with varying pH (10.4, 7.4 or 4.4). The solutions were collected and renewed at various time intervals. pH and/or calcium ion release was measured using a pH glass electrode and atomic absorption spectrophotometer respectively. The change of pH, short-term calcium ion release and rate at which calcium ion release reaches maximum were dependent on ESA (p < 0.05) while maximum calcium ion release was dependent on Vol of TSC (p < 0.05). Maximum calcium ion release was significantly higher in acidic solution followed by neutral and alkaline solution (p < 0.05). PMID:29342837

Large Calcium Isotopic Variation in Peridotitic Xenoliths from North China Craton

NASA Astrophysics Data System (ADS)

Huang, S.; Zhao, X.; Zhang, Z.

2016-12-01

Calcium is the fifth most abundant element in the Earth. The Ca isotopic composition of the Earth is important in many aspects, ranging from tracing the Ca cycle on the Earth to comparing the Earth to other terrestrial planets. There is large mass-dependent Ca isotopic variation, measured as δ44/40Ca relative to a standard sample, in terrestrial igneous rocks: about 2 per mil in silicate rocks, compared to 3 per mil in carbonates. Therefore, a good understanding of the Ca isotopic variation in igneous rocks is necessary. Here we report Ca isotopic data on a series of peridotitic xenoliths from North China Craton (NCC). There is about 1 per mil δ44/40Ca variation in these NCC peridotites: The highest δ44/40Ca is close to typical mantle values, and the lowest δ44/40Ca is found in an Fe-rich peridotite, -1.13 relative to normal mantle (or -0.08 on the SRM 915a scale). This represents the lowest δ44/40Ca value ever reported for igneous rocks. Combined with published Fe isotopic data on the same samples, our data show a positive linear correlation between δ44/40Ca and δ57/54Fe in NCC peridotites. This trend is inconsistent with mixing a low-δ44/40Ca and -δ57/54Fe sedimentary component with a normal mantle component. Rather, it is best explained as the result of kinetic isotopic effect caused by melt-peridotite reaction on a time scale of several hundreds of years. In detail, basaltic melt reacts with peridotite, replaces orthopyroxene with clinopyroxene, and increases the Fo number of olivine. Consistent with this interpretation, our on-going Mg isotopic study shows that low-δ44/40Ca and -δ57/54Fe NCC peridotites also have heavier Mg isotopes compared to normal mantle. Our study shows that mantle metasomatism plays an important role generating stable isotopic variations within the Earth's mantle.

Dietary fat and not calcium supplementation or dairy product consumption is associated with changes in anthropometrics during a randomized, placebo-controlled energy-restriction trial

PubMed Central

2011-01-01

Insufficient calcium intake has been proposed to cause unbalanced energy partitioning leading to obesity. However, weight loss interventions including dietary calcium or dairy product consumption have not reported changes in lipid metabolism measured by the plasma lipidome. Methods The objective of this study was to determine the relationships between dairy product or supplemental calcium intake with changes in the plasma lipidome and body composition during energy restriction. A secondary objective of this study was to explore the relationships among calculated macronutrient composition of the energy restricted diet to changes in the plasma lipidome, and body composition during energy restriction. Overweight adults (n = 61) were randomized into one of three intervention groups including a deficit of 500kcal/d: 1) placebo; 2) 900 mg/d calcium supplement; and 3) 3-4 servings of dairy products/d plus a placebo supplement. Plasma fatty acid methyl esters of cholesterol ester, diacylglycerol, free fatty acids, lysophosphatidylcholine, phosphatidylcholine, phosphatidylethanolamine and triacylglycerol were quantified by capillary gas chromatography. Results After adjustments for energy and protein (g/d) intake, there was no significant effect of treatment on changes in weight, waist circumference or body composition. Plasma lipidome did not differ among dietary treatment groups. Stepwise regression identified correlations between reported intake of monounsaturated fat (% of energy) and changes in % lean mass (r = -0.44, P < 0.01) and % body fat (r = 0.48, P < 0.001). Polyunsaturated fat intake was associated with the % change in waist circumference (r = 0.44, P < 0.01). Dietary saturated fat was not associated with any changes in anthropometrics or the plasma lipidome. Conclusions Dairy product consumption or calcium supplementation during energy restriction over the course of 12 weeks did not affect plasma lipids. Independent of calcium and dairy product consumption, short-term energy restriction altered body composition. Reported dietary fat composition of energy restricted diets was associated with the degree of change in body composition in these overweight and obese individuals. PMID:21970320

Calcium/Vitamin D Supplementation and Coronary Artery Calcification

PubMed Central

Manson, JoAnn E.; Allison, Matthew A.; Carr, J. Jeffrey; Langer, Robert D.; Cochrane, Barbara B.; Hendrix, Susan L.; Hsia, Judith; Hunt, Julie R.; Lewis, Cora E.; Margolis, Karen L.; Robinson, Jennifer G.; Rodabough, Rebecca J.; Thomas, Asha M.

2010-01-01

Objectives Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events. The relationship between calcium plus vitamin D supplementation and coronary artery calcium (CAC) has not been previously assessed in a randomized trial setting. We compared coronary artery calcium scores among women randomized to calcium/vitamin D supplementation versus placebo following trial completion. Methods In an ancillary substudy of women randomized to calcium carbonate (1000 mg of elemental calcium daily) plus vitamin D3 (400 IU daily) versus placebo, nested within the Women’s Health Initiative trial of estrogen among women with hysterectomy, we measured CAC with cardiac computed tomography in 754 women aged 50–59 years at randomization. Imaging for CAC was performed at 28 of 40 centers following a mean of 7 years of treatment and scans were read centrally. Coronary artery calcium scores were measured by a central reading center with masking to randomization assignments. Results Post-trial CAC measurements were similar in women randomized to calcium/vitamin D supplementation (calcium/D) and those receiving placebo. The mean CAC score was 91.6 for calcium/D and 100.5 for placebo (rank test p-value=0.74). After adjustment for coronary risk factors, multivariate odds ratios for increasing CAC score cutpoints (CAC >0, ≥10, and ≥100) for calcium/D vs placebo were 0.92 (95% confidence interval, 0.64–1.34), 1.29 (0.88–1.87), and 0.90 (0.56–1.44), respectively. Corresponding odds ratios among women with >50% adherence to study pills and for higher levels of CAC (>300), were similar. Conclusions Treatment with moderate doses of calcium plus vitamin D3 did not appear to alter coronary artery calcified plaque burden among postmenopausal women. PMID:20551849

The calcium concentration of public drinking waters and bottled mineral waters in Spain and its contribution to satisfying nutritional needs.

PubMed

Vitoria, Isidro; Maraver, Francisco; Ferreira-Pêgo, Cíntia; Armijo, Francisco; Moreno Aznar, Luis; Salas-Salvadó, Jordi

2014-07-01

A sufficient intake of calcium enables correct bone mineralization. The bioavailability of calcium in water is similar to that in milk. To determine the concentration of calcium in public drinking water and bottled mineral water. We used ion chromatography to analyse the calcium concentrations of public drinking waters in a representative sample of 108 Spanish municipalities (21,290,707 people) and of 109 natural mineral waters sold in Spain, 97 of which were produced in Spain and 12 of which were imported. The average calcium concentration of public drinking waters was 38.96 ± 32.44 mg/L (range: 0.40- 159.68 mg/L). In 27 municipalities, the water contained 50-100 mg/L of calcium and in six municipalities it contained over 100 mg/L. The average calcium concentration of the 97 Spanish natural mineral water brands was 39.6 mg/L (range: 0.6-610.1 mg/L). Of these, 34 contained 50-100 mg/L of calcium and six contained over 100 mg/L. Of the 12 imported brands, 10 contained over 50 mg/L. Assuming water consumption is as recommended, water containing 50-100 mg/L of calcium provides 5.4-12.8% of the recommended intake of calcium for children aged one to thirteen, up to 13.6% for adolescents, 5.8-17.6% for adults, and up to 20.8% for lactating mothers. Water with 100-150 mg/L of calcium provides 10-31% of the recommended dietary allowance, depending on the age of the individual. Public drinking water and natural mineral water consumption in a third of Spanish cities can be considered an important complementary source of calcium. Copyright AULA MEDICA EDICIONES 2014. Published by AULA MEDICA. All rights reserved.

Calcium isotope systematics in small upland catchments affected by spruce dieback in the period of extreme acid rain (1970-1990)

NASA Astrophysics Data System (ADS)

Novak, Martin; Farkas, Juraj; Holmden, Chris; Hruska, Jakub; Curik, Jan; Stepanova, Marketa; Prechova, Eva; Veselovsky, Frantisek; Komarek, Arnost

2017-04-01

Recently, new isotope tools have become available to study the behavior of nutrients in stressed ecosystems. In this study, we focus on changes in the abundance ratio of calcium (Ca) isotopes accompanying biogeochemical processes in small forested catchments. We monitored del44Ca values in ecosystem pools and fluxes in four upland sites situated in the Czech Republic, Central Europe. A heavily acidified site in the Eagle Mts. (northern Czech Republic) experienced 13 times higher atmospheric Ca inputs, compared to the other three sites, which were less affected by forest decline. Industrial dust was responsible for the elevated Ca input. Del44Ca values of individual poos/fluxes were used to identify Ca sources for the bioavailable Ca soil reservoir and for runoff. The bedrock of the study sites differed (leucogranite, orthogneiss vs. serpentinite and amphibolite). Across the sites, mean del44Ca values increased in the order: spruce bark < fine roots < needles < soil < bedrock < canopy throughfall < open-area precipitation < runoff < soil water. Plant preferentially took up isotopically light Ca, while residual isotopically heavy Ca was sorbed to soil particles or exported via runoff. Even at sites with a low del44Ca values of bedrock, runoff had a high del44Ca value. At the base-poor site, most runoff came from atmospheric deposition and residual Ca following plant uptake. It appeared that bedrock weathering did not supply enough Ca to replenish the bioavailable Ca pool in the soil. Currently, we are analyzing Ca isotope composition of individual rock-forming minerals to better assess the effect of different weathering rates of minerals with low/high radiogenic 40Ca contents on runoff del44Ca.

Characterization of semi-solid Self-Emulsifying Drug Delivery Systems (SEDDS) of atorvastatin calcium by Raman image spectroscopy and chemometrics.

PubMed

Breitkreitz, Márcia C; Sabin, Guilherme P; Polla, Griselda; Poppi, Ronei J

2013-01-25

A methodology based on Raman image spectroscopy and chemometrics for homogeneity evaluation of formulations containing atorvastatin calcium in Gelucire(®) 44/14 is presented. In the first part of the work, formulations with high amounts of Gelucire(®) 44/14 (80%) and solvents of different polarities (diethylene glycol monoethyl ether, propyleneglycol, propylene glycol monocaprylate and glyceryl mono/dicaprylate/caprate) were prepared for miscibility screening evaluation by classical least squares (CLS). It was observed that Gelucire(®) 44/14 presented higher affinity for the lipophilic solvents glyceryl mono/dicaprylate/caprate and propylene glycol monocaprylate, whose samples were observed to be homogeneous, and lower affinity for the hydrophilic solvents diethylene glycol monoethyl ether and propyleneglycol, whose samples were heterogeneous. In the second part of the work, the ratio of glyceryl mono/dicaprylate/caprate and Gelucire(®) 44/14 was determined based on studies in water and allowed the selection of the proportions of these two excipients in the preconcentrate that provided supersaturation of atorvastatin upon dilution. The preconcentrate was then evaluated for homogeneity by partial least squares (PLS) and an excellent miscibility was observed in this proportion as well. Therefore, it was possible to select a formulation that presented simultaneously homogeneous preconcentrate and solubility enhancement in water by Raman image spectroscopy and chemometrics. Copyright © 2012 Elsevier B.V. All rights reserved.

Elemental calcium intake associated with calcium acetate/calcium carbonate in the treatment of hyperphosphatemia

PubMed Central

Wilson, Rosamund J; Copley, J Brian

2017-01-01

Background Calcium-based and non-calcium-based phosphate binders have similar efficacy in the treatment of hyperphosphatemia; however, calcium-based binders may be associated with hypercalcemia, vascular calcification, and adynamic bone disease. Scope A post hoc analysis was carried out of data from a 16-week, Phase IV study of patients with end-stage renal disease (ESRD) who switched to lanthanum carbonate monotherapy from baseline calcium acetate/calcium carbonate monotherapy. Of the intent-to-treat population (N=2520), 752 patients with recorded dose data for calcium acetate (n=551)/calcium carbonate (n=201) at baseline and lanthanum carbonate at week 16 were studied. Elemental calcium intake, serum phosphate, corrected serum calcium, and serum intact parathyroid hormone levels were analyzed. Findings Of the 551 patients with calcium acetate dose data, 271 (49.2%) had an elemental calcium intake of at least 1.5 g/day at baseline, and 142 (25.8%) had an intake of at least 2.0 g/day. Mean (95% confidence interval [CI]) serum phosphate levels were 6.1 (5.89, 6.21) mg/dL at baseline and 6.2 (6.04, 6.38) mg/dL at 16 weeks; mean (95% CI) corrected serum calcium levels were 9.3 (9.16, 9.44) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Of the 201 patients with calcium carbonate dose data, 117 (58.2%) had an elemental calcium intake of at least 1.5 g/day, and 76 (37.8%) had an intake of at least 2.0 g/day. Mean (95% CI) serum phosphate levels were 5.8 (5.52, 6.06) mg/dL at baseline and 5.8 (5.53, 6.05) mg/dL at week 16; mean (95% CI) corrected serum calcium levels were 9.7 (9.15, 10.25) mg/dL and 9.2 (9.06, 9.34) mg/dL, respectively. Conclusion Calcium acetate/calcium carbonate phosphate binders, taken to control serum phosphate levels, may result in high levels of elemental calcium intake. This may lead to complications related to calcium balance. PMID:28182142

Fructo-oligosaccharides and calcium absorption and retention in adolescent girls.

PubMed

Martin, Berdine R; Braun, Michelle M; Wigertz, Karin; Bryant, Rebecca; Zhao, Yongdong; Lee, WangHee; Kempa-Steczko, Ania; Weaver, Connie M

2010-08-01

Several studies have shown a positive effect of fructo-oligosaccharides on calcium absorption and retention in animals and humans. Effects of levels of these pre-biotics that can be functionally incorporated into manufactured foods, have not been studied in controlled feeding studies. This study was designed to evaluate the effect of 9 g/d of fructo-oligosaccharides as part of a controlled diet on calcium absorption and retention in adolescent girls. Fourteen healthy adolescent girls aged 11-13 y were studied in a metabolic setting for two 3-week periods separated by a 2-week washout period. In a randomized, double-blinded, crossover design, the teens received a diet containing either 9 g/d oligofructose-enriched inulin in a calcium-fortified cereal or the control cereal with no inulin. Both diets contained ~1500 mg calcium daily. Calcium retention was determined on the third week of each period. On day 14 of the diet period, fractional calcium absorption was determined from the enrichment of (44)Ca in 4-day urine collections. Calcium absorption (67 ± 3 vs. 66 ± 3%) and retention (409 ± 394 vs. 464 ± 241 mg/d) were not significantly different when diets contained 9 g/d oligofructose-enriched inulin or not in a calcium-fortified cereal. Daily consumption of cereal containing a combination of short- and long-chain fructo-oligosaccharides as part of a controlled diet did not benefit calcium absorption or retention in adolescent girls. Lack of response to the prebiotic in this cohort may relate to their already high calcium absorption efficiency.

Soluble Corn Fiber Increases Calcium Absorption Associated with Shifts in the Gut Microbiome: A Randomized Dose-Response Trial in Free-Living Pubertal Females.

PubMed

Whisner, Corrie M; Martin, Berdine R; Nakatsu, Cindy H; Story, Jon A; MacDonald-Clarke, Claire J; McCabe, Linda D; McCabe, George P; Weaver, Connie M

2016-07-01

Soluble corn fiber (SCF; 12 g fiber/d) is shown to increase calcium absorption efficiency, associated with shifts in the gut microbiota in adolescent males and females who participated in a controlled feeding study. We evaluated the dose response of 0, 10, and 20 g fiber/d delivered by PROMITOR SCF 85 (85% fiber) on calcium absorption, biochemical bone properties, and the fecal microbiome in free-living adolescents. Healthy adolescent females (n = 28; aged 11-14 y) randomly assigned into a 3-phase, double-blind, crossover study consumed SCF for 4 wk at each dose (0, 10, and 20 g fiber/d from SCF) alongside their habitual diet and were followed by 3-d clinical visits and 3-wk washout periods. Stable isotope ((44)Ca and (43)Ca) enrichment in pooled urine was measured by inductively coupled plasma mass spectrometry. Fecal microbial community composition was assessed by high-throughput sequencing (Illumina) of polymerase chain reaction-amplified 16S rRNA genes. Mixed model ANOVA and Friedman analysis were used to determine effects of SCF on calcium absorption and to compare mean microbial proportions, respectively. Calcium absorption increased significantly with 10 (13.3% ± 5.3%; P = 0.042) and 20 g fiber/d (12.9% ± 3.6%; P = 0.026) from SCF relative to control. Significant differences in fecal microbial community diversity were found after consuming SCF (operational taxonomic unit measures of 601.4 ± 83.5, 634.5 ± 83.8, and 649.6 ± 75.5 for 0, 10, and 20 g fiber/d, respectively; P < 0.05). Proportions of the genus Parabacteroides significantly increased with SCF dose (1.1% ± 0.8%, 2.1% ± 1.6%, and 3.0% ± 2.0% for 0, 10, and 20 g fiber/d from SCF, respectively; P < 0.05). Increases in calcium absorption positively correlated with increases in Clostridium (r = 0.44, P = 0.023) and unclassified Clostridiaceae (r = 0.40, P = 0.040). SCF, a nondigestible carbohydrate, increased calcium absorption in free-living adolescent females. Two groups of bacteria may be involved, one directly fermenting SCF and the second fermenting SCF metabolites further, thereby promoting increased calcium absorption. This trial was registered at clinicaltrials.gov as NCT01660503. © 2016 American Society for Nutrition.

Porcine malignant hyperthermia susceptibility: hypersensitive calcium-release mechanism of skeletal muscle sarcoplasmic reticulum.

PubMed Central

O'Brien, P J

1986-01-01

This study tested the hypothesis that calcium-release from sarcoplasmic reticulum isolated from malignant hyperthermia swine had abnormal concentration-dependency on release modulators. Halothane stimulated half-maximal calcium-release at similar concentrations for malignant hyperthermia and control sarcoplasmic reticulum (0.10 +/- 0.04 mM). However, concentrations causing half-maximal calcium-release were lower for malignant hyperthermia sarcoplasmic reticulum (P less than 0.001) by an order of magnitude for Ca2+ (28.1 +/- 8.3 versus 1.23 +/- 0.45 nM), adenosine triphosphate (0.33 +/- 0.09 versus 0.023 +/- 0.014 mM) and caffeine (7.79 +/- 1.56 versus 0.80 +/- 0.44 mM). Half-maximal inhibition by Mg2+ occurred at threefold higher concentrations for malignant hyperthermia sarcoplasmic reticulum (0.23 +/- 0.02 versus 0.78 +/- 0.17 mM). The Ca2+-sensitivity curves for calcium-release by sarcoplasmic reticulum isolated from heterozygotes for the malignant hyperthermia-defect were indistinguishable from the averages of the curves for controls and malignant hyperthermia-homozygotes. Results of this study suggest that malignant hyperthermia is initiated due to a hypersensitive calcium-release mechanism which is inherited in an autosomal, codominant pattern and may be diagnosed using calcium-release sensitivity-tests on isolated sarcoplasmic reticulum. Images Fig. 1. PMID:3742367

Calcium Treatment for FeSi-killed Fe-13 Pct Cr Stainless Steel with Various Top Slag Compositions

NASA Astrophysics Data System (ADS)

Wang, Qi; Wang, Lijun; Zhai, Jun; Li, Jianmin; Chou, Kuochih

2018-02-01

Calcium treatment of Fe-13 pct Cr stainless steel, with inclusion modification as its main purpose, was evaluated on a laboratory scale. The stability diagram of Ca-Al was obtained using the FactSage software and could be divided into three parts based on the [Al] content: the ultra-low-Al region, the low-Al region, and the medium-high-Al region. Each of these regions required different amounts of calcium for inclusion modification. The ferrosilicon deoxidation product could be modified into low melting temperature inclusions by a CaO-SiO2 top slag in the ultra-low-Al region ([Al] content less than 40 ppm). Calcium treatment was necessary to modify the ferrosilicon deoxidation product into low melting temperature inclusions in the low-Al region ([Al] content from 40 to 100 ppm) for the CaO-SiO2-Al2O3 top slag. Calcium addition has a "liquid window" where adding calcium can accelerate inclusion modification. Adding calcium for 15 and 30 minutes resulted in complete modification times of 45 and 60 minutes, respectively, which indicates that early calcium treatment can produce plastic inclusions sooner. The relationship between the steel and inclusion content was determined by fitting the experimental data in the low-Al region. An appropriate range of T.Ca/T.O (total calcium content/total oxygen content) for inclusion modification is 0.99 to 1.44.

Arsenic mobility controlled by solid calcium arsenates: a case study in Mexico showcasing a potentially widespread environmental problem.

PubMed

Martínez-Villegas, Nadia; Briones-Gallardo, Roberto; Ramos-Leal, José A; Avalos-Borja, Miguel; Castañón-Sandoval, Alan D; Razo-Flores, Elías; Villalobos, Mario

2013-05-01

An As-contaminated perched aquifer under an urban area affected by mining was studied over a year to determine the contamination source species and the mechanism of As mobilization. Results show that the dissolution of calcium arsenates in residues disposed on an inactive smelter has caused high levels of As pollution in the adjoining downgradient 6-km perched aquifer, reaching up to 158 mg/L of dissolved As, and releasing a total of ca. 7.5 tons of As in a year. Furthermore, free calcium ion availability was found to control As mobility in the aquifer through the diagenetic precipitation of calcium arsenates (Ca5H2(AsO4)4·cH2O) preventing further mobilization of As. Results shown here represent a model for understanding a highly underreported mechanism of retention of arsenate species likely to dominate in calcium-rich environments, such as those in calcareous sediments and soils, where the commonly reported mechanism of adsorption to iron(III) oxyhydroxides is not the dominant process. Copyright © 2013 Elsevier Ltd. All rights reserved.

Seawater calcium isotope ratios across the Eocene-Oligocene transition

USGS Publications Warehouse

Griffith, E.M.; Paytan, A.; Eisenhauer, A.; Bullen, T.D.; Thomas, E.

2011-01-01

During the Eocene-Oligocene transition (EOT, ca. 34 Ma), Earth's climate cooled significantly from a greenhouse to an icehouse climate, while the calcite (CaCO3) compensation depth (CCD) in the Pacific Ocean increased rapidly. Fluctuations in the CCD could result from various processes that create an imbalance between calcium (Ca) sources to, and sinks from, the ocean (e.g., weathering and CaCO3 deposition), with different effects on the isotopic composition of dissolved Ca in the oceans due to differences in the Ca isotopic composition of various inputs and outputs. We used Ca isotope ratios (??44/40Ca) of coeval pelagic marine barite and bulk carbonate to evaluate changes in the marine Ca cycle across the EOT. We show that the permanent deepening of the CCD was not accompanied by a pronounced change in seawater ??44/40Ca, whereas time intervals in the Neogene with smaller carbonate depositional changes are characterized by seawater ??44/40Ca shifts. This suggests that the response of seawater ??44/40Ca to changes in weathering fluxes and to imbalances in the oceanic alkalinity budget depends on the chemical composition of seawater. A minor and transient fluctuation in the Ca isotope ratio of bulk carbonate may reflect a change in isotopic fractionation associated with CaCO3 precipitation from seawater due to a combination of factors, including changes in temperature and/or in the assemblages of calcifying organisms. ?? 2011 Geological Society of America.

Effect of Oestrogen on Altering the Serum and Urinary Levels of Calcium, Phosphate and Magnesium in Hysterectomised Women Compared to Natural Menopausal South Indian Women: A Case Control Study.

PubMed

Sonu, Yeldose; Avinash, S S; Sreekantha; Arun Kumar, K; Malathi, M; Shivashankara, A R

2016-07-01

Given the paucity of studies conducted to know the effect of suddenness and earlier onset of endocrinological changes associated with hysterectomy, on the serum and urinary levels of calcium, magnesium and phosphate the present study was conducted to compare the levels of calcium, magnesium and phosphate in serum and urine of hysterectomised and natural menopausal south Indian women. This is a cross-sectional observational study. The study included three groups of 30 healthy premenopausal, 30 early surgical menopausal and 30 natural post menopausal women. Women suffering from any endocrine disease were excluded. Analysis was performed in serum and urine sample. The levels of calcium, magnesium and phosphate in serum and calcium/creatinine, magnesium/creatinine and phosphate/creatinine ratio were estimated in urine by spectrophotometric method. Hysterectomised women (serum calcium: 8.7 ± 0.09 mg/dl; urine calcium/creatinine: 0.16 ± 0.02) have significantly low serum calcium (p < 0.001) and high urinary calcium/creatinine (p = 0.002) ratio and post menopausal women (serum magnesium: 2.1 ± 0.03; serum phosphate: 4.4 ± 0.16; urinary calcium/creatinine: 0.17 ± 0.02; urinary magnesium/creatinine: 0.09 ± 0.01) have significantly high serum magnesium (p = 0.016), serum phosphate (p = 0.043) and high urinary calcium/creatinine (p = 0.002), magnesium/creatinine ratio (p = 0.025) compared to healthy pre menopausal women. Post menopausal women (serum calcium: 9.1 ± 0.08) have significantly high serum calcium and phosphate compared to hysterectomised women (serum phosphate: 3.93 ± 0.11). Hysterectomised women have significantly low serum calcium, oestrogen and high urinary calcium/creatinine ratio compared to healthy premenopausal women and low serum calcium and low serum phosphate compared to natural postmenopausal women. Natural postmenopausal women had low serum oestrogen and high serum magnesium, serum phosphate, urinary calcium creatinine ratio and urinary magnesium creatinine ratio compared to healthy premenopausal women.

Investigation of the effects of vitamin D and calcium on intestinal motility: In vitro tests and implications for clinical treatment.

PubMed

Giraldi, Guglielmo; Fioravanti, Angelo; De Luca d'Alessandro, Eugenia; Palmery, Maura; Martinoli, Lucia

2015-09-01

The presence of vitamin D receptors in small intestine muscle cells may lead one to think that vitamin D may act locally, influencing intracellular calcium concentration and contributing to the contraction-relaxation regulation of the intestinal smooth muscle cells. This study investigates the potential effects of vitamin D and calcium on intestinal motility using an in vitro test. Different calcium concentrations added to the tissue not pre-treated with 1,25-dihydroxycholecalciferol [1α,25(OH)2D3] produced no response at low doses (1.25 × 10-3 and 2.0 × 10-3 mol L-1) and only a very weak response at higher concentration (3.0 × 10-3 mol L-1). The addition of 1α,25(OH)2D3 (1.44 × 10-10 mol L-1) had no effect on isolated ileum motility. When calcium (3.0 × 10-3 mol L-1) was added after at least 3 hours, it evoked evident and persistent contractions for 60-90 minutes. The contractions were at about 40 % of the peak produced by acetylcholine. Thus, simultaneous intake of vitamin D and calcium might be a useful co-adjuvant in intestinal atony therapy aimed to stimulate normal gut motility in humans. These findings imply that supplemental vitamin D may be important in all cases where calcium has to be prescribed.

Supplementing a low-protein diet with dibasic amino acids increases urinary calcium excretion in young women.

PubMed

Bihuniak, Jessica D; Sullivan, Rebecca R; Simpson, Christine A; Caseria, Donna M; Huedo-Medina, Tania B; O'Brien, Kimberly O; Kerstetter, Jane E; Insogna, Karl L

2014-03-01

Increasing dietary protein within a physiologic range stimulates intestinal calcium absorption, but it is not known if specific amino acids or dietary protein as a whole are responsible for this effect. Therefore, we selectively supplemented a low-protein (0.7 g/kg) diet with either the calcium-sensing receptor-activating amino acids (CaSR-AAAs) L-tryptophan, L-phenylalanine, and L-histidine, or the dibasic amino acids (DAAs) L-arginine and L-lysine, to achieve intakes comparable to the content of a high-protein diet (2.1 g/kg) and measured intestinal calcium absorption. Fourteen young women took part in a placebo-controlled, double-blind, crossover feeding trial in which each participant ingested a 6-d low-protein diet supplemented with CaSR-AAAs, DAAs, or methylcellulose capsules (control) after an 11-d adjustment period. All participants ingested all 3 diets in random order. Intestinal calcium absorption was measured between days 5 and 6 using dual-stable calcium isotopes ((42)Ca, (43)Ca, and (44)Ca). There was no difference in calcium absorption between the diet supplemented with CaSR-AAAs (22.9 ± 2.0%) and the control diet (22.3 ± 1.4%) (P = 0.64). However, calcium absorption tended to be greater during the DAA supplementation period (25.2 ± 1.4%) compared with the control diet period (22.3 ± 1.4%) (P < 0.10). Larger and longer clinical trials are needed to clarify the possible benefit of arginine and lysine on calcium absorption.

Characterization of calcium isotopes in natural and synthetic barite

USGS Publications Warehouse

Griffith, E.M.; Schauble, E.A.; Bullen, T.D.; Paytan, A.

2008-01-01

The mineral barite (BaSO4) accommodates calcium in its crystal lattice, providing an archive of Ca-isotopes in the highly stable sulfate mineral. Holocene marine (pelagic) barite samples from the major ocean basins are isotopically indistinguishable from each other (??44/40Ca = -2.01 ?? 0.15???) but are different from hydrothermal and cold seep barite samples (??44/40Ca = -4.13 to -2.72???). Laboratory precipitated (synthetic) barite samples are more depleted in the heavy Ca-isotopes than pelagic marine barite and span a range of Ca-isotope compositions, ??44/40Ca = -3.42 to -2.40???. Temperature, saturation state, a Ba2 + / a SO42 -, and aCa2+/aBa2+ each influence the fractionation of Ca-isotopes in synthetic barite; however, the fractionation in marine barite samples is not strongly related to any measured environmental parameter. First-principles lattice dynamical modeling predicts that at equilibrium Ca-substituted barite will have much lower 44Ca/40Ca than calcite, by -9??? at 0 ??C and -8??? at 25 ??C. Based on this model, none of the measured barite samples appear to be in isotopic equilibrium with their parent solutions, although as predicted they do record lower ??44/40Ca values than seawater and calcite. Kinetic fractionation processes therefore most likely control the extent of isotopic fractionation exhibited in barite. Potential fractionation mechanisms include factors influencing Ca2+ substitution for Ba2+ in barite (e.g. ionic strength and trace element concentration of the solution, competing complexation reactions, precipitation or growth rate, temperature, pressure, and saturation state) as well as nucleation and crystal growth rates. These factors should be considered when investigating controls on isotopic fractionation of Ca2+ and other elements in inorganic and biogenic minerals. ?? 2008 Elsevier Ltd.

Influences of calcium availability and tree species on Ca isotope fractionation in soil and vegetation

USGS Publications Warehouse

Page, B.D.; Bullen, T.D.; Mitchell, M.J.

2008-01-01

The calcium (Ca) isotope system is potentially of great use for understanding biogeochemical processes at multiple scales in forest ecosystems, yet remains largely unexplored for this purpose. In order to further our understanding of Ca behavior in forests, we examined two nearly adjacent hardwood-dominated catchments with differing soil Ca concentrations, developed from crystalline bedrock, to determine the variability of 44Ca/ 40Ca ratios (expressed as ??44Ca) within soil and vegetation pools. For both sugar maple and American beech, the Ca isotope compositions of the measured roots and calculated bulk trees were considerably lighter than those of soil pools at these sites, suggesting that the trees were able to preferentially take up light Ca at the root-soil interface. The Ca isotope compositions of three of four root samples were among the lightest values yet reported for terrestrial materials (??44Ca ???-3.95???). Our results further indicate that Ca isotopes were fractionated along the transpiration streams of both tree species with roots having the least ??44Ca values and leaf litter the greatest. An approximately 2??? difference in ??44Ca values between roots and leaf litter of both tree species suggests a persistent fractionation mechanism along the transpiration stream, likely related to Ca binding in wood tissue coupled with internal ion exchange. Finally, our data indicate that differing tree species demand for Ca and soil Ca concentrations together may influence Ca isotope distribution within the trees. Inter-catchment differences in Ca isotope distributions in soils and trees were minor, indicating that the results of our study may have broad transferability to studies of forest ecosystems in catchments developed on crystalline substrates elsewhere. ?? 2008 Springer Science+Business Media B.V.

An experimental model for calcium carbonate urolithiasis in goats

PubMed Central

Dominguez, Brandon J.; Deveau, Michael A.

2018-01-01

Background Calcium carbonate is a common urolith type in small ruminants with no high‐yield experimental model to evaluate animal susceptibility or preventative measure response. Hypothesis That novel plastic winged implants would allow accumulation and quantification of calcium carbonate calculus formation in goats on a high‐calcium diet and identify individual variation between goats in the mass of calculi produced. Animals Eight nonpregnant 3‐ and 4‐year‐old Boer‐cross does, weighing 22.3–39.5 kg, determined to be healthy based on physical examination, were used in these experiments. Methods Prospective cohort study for in vivo experimental model development. Implants were placed into the urinary bladder lumen in 8 goats over 2 evaluation periods. The alfalfa‐based ration had a total ration Ca : P of 3.29 and 3.84 : 1, respectively. Urine was collected at 0, 28, 56, and 84 days in the 1st experiment; blood and urine at those timepoints in the 2nd experiment. For each evaluation period, the implants were removed 84 days after implantation and weighed. Accumulated calculi mass was calculated and compared between goats and was analyzed for composition. Results Implant retention was 100% and 86% in the 2 studies. All goats with retained implants accumulated calcium carbonate at a mean implant gain per day across studies ranging from 0.44 to 57.45 mg. Two goats accumulated (0.44–7.65 mg/day and 33.64 & 57.45 mg/day) significantly more urolith material than the cohort across both studies (P = .047). No routine analytes on blood or urine were found to be explanatory for the difference observed. Conclusions and Clinical Importance These findings form a basis for implant and diet selection for use in future studies of urolithiasis development and for studies regarding individual susceptibility to urolithiasis. PMID:29524246

An experimental model for calcium carbonate urolithiasis in goats.

PubMed

Jones, Meredyth L; Dominguez, Brandon J; Deveau, Michael A

2018-05-01

Calcium carbonate is a common urolith type in small ruminants with no high-yield experimental model to evaluate animal susceptibility or preventative measure response. That novel plastic winged implants would allow accumulation and quantification of calcium carbonate calculus formation in goats on a high-calcium diet and identify individual variation between goats in the mass of calculi produced. Eight nonpregnant 3- and 4-year-old Boer-cross does, weighing 22.3-39.5 kg, determined to be healthy based on physical examination, were used in these experiments. Prospective cohort study for in vivo experimental model development. Implants were placed into the urinary bladder lumen in 8 goats over 2 evaluation periods. The alfalfa-based ration had a total ration Ca : P of 3.29 and 3.84 : 1, respectively. Urine was collected at 0, 28, 56, and 84 days in the 1st experiment; blood and urine at those timepoints in the 2nd experiment. For each evaluation period, the implants were removed 84 days after implantation and weighed. Accumulated calculi mass was calculated and compared between goats and was analyzed for composition. Implant retention was 100% and 86% in the 2 studies. All goats with retained implants accumulated calcium carbonate at a mean implant gain per day across studies ranging from 0.44 to 57.45 mg. Two goats accumulated (0.44-7.65 mg/day and 33.64 & 57.45 mg/day) significantly more urolith material than the cohort across both studies (P = .047). No routine analytes on blood or urine were found to be explanatory for the difference observed. These findings form a basis for implant and diet selection for use in future studies of urolithiasis development and for studies regarding individual susceptibility to urolithiasis. Copyright © 2018 The Authors. Journal of Veterinary Internal Medicine published by Wiley Periodicals, Inc. on behalf of the American College of Veterinary Internal Medicine.

Cardiac basal metabolism: energetic cost of calcium withdrawal in the adult rat heart.

PubMed

Bonazzola, P; Takara, D

2010-07-01

Cardiac basal metabolism upon extracellular calcium removal and its relationship with intracellular sodium and calcium homeostasis was evaluated. A mechano-calorimetric technique was used that allowed the simultaneous and continuous measurement of both heat rate and resting pressure in arterially perfused quiescent adult rat hearts. Using pharmacological tools, the possible underlying mechanisms related to sodium and calcium movements were investigated. Resting heat rate (expressed in mW g(-1)(dry wt)) increased upon calcium withdrawal (+4.4 +/- 0.2). This response was: (1) unaffected by the presence of tetrodotoxin (+4.3 +/- 0.6), (2) fully blocked by both, the decrease in extracellular sodium concentration and the increase in extracellular magnesium concentration, (3) partially blocked by the presence of either nifedipine (+2.8 +/- 0.4), KB-R7943 (KBR; +2.5 +/- 0.2), clonazepam (CLO; +3.1 +/- 0.3) or EGTA (+1.9 +/- 0.3). The steady heat rate under Ca(2+)-free conditions was partially reduced by the addition of Ru360 (-1.1 +/- 0.2) but not CLO in the presence of EGTA, KBR or Ru360. Energy expenditure for resting state maintenance upon calcium withdrawal depends on the intracellular rise in both sodium and calcium. Our data are consistent with a mitochondrial Ca(2+) cycling, not detectable under normal calcium diastolic levels. The experimental condition here analysed, partially simulates findings reported under certain pathological situations including heart failure in which mildly increased levels of both diastolic sodium and calcium have also been found. Therefore, under such pathological conditions, hearts should distract chemical energy to fuel processes associated with sodium and calcium handling, making more expensive the maintenance of their functions.

Compressive strength and magnetic properties of calcium silicate-zirconia-iron (III) oxide composite cements

NASA Astrophysics Data System (ADS)

Ridzwan, Hendrie Johann Muhamad; Shamsudin, Roslinda; Ismail, Hamisah; Yusof, Mohd Reusmaazran; Hamid, Muhammad Azmi Abdul; Awang, Rozidawati Binti

2018-04-01

In this study, ZrO2 microparticles and γ-Fe2O3 nanoparticles have been added into calcium silicate based cements. The purpose of this experiment was to investigate the compressive strength and magnetic properties of the prepared composite cement. Calcium silicate (CAS) powder was prepared by hydrothermal method. SiO2 and CaO obtained from rice husk ash and limestone respectively were autoclaved at 135 °C for 8 h and sintered at 950°C to obtain CAS powder. SiO2:CaO ratio was set at 45:55. CAS/ZrO2 sample were prepared with varying ZrO2 microparticles concentrations by 0-40 wt. %. Compressive strength value of CAS/ZrO2 cements range from 1.44 to 2.44 MPa. CAS/ZrO2/γ-Fe2O3 sample with 40 wt. % ZrO2 were prepared with varying γ-Fe2O3 nanoparticles concentrations (1-5 wt. %). The additions of γ-Fe2O3 nanoparticles showed up to twofold increase in the compressive strength of the cement. X-Ray diffraction (XRD) results confirm the formation of mixed phases in the produced composite cements. Vibrating sample magnetometer (VSM) analysis revealed that the ferromagnetic behaviour has been observed in CAS/ZrO2/γ-Fe2O3 composite cements.

Immunosuppressive Interactions among Calcium Channel Antagonists and Selected Corticosteroids and Macrolides Using Human whole Blood Lymphocytes

PubMed Central

Chow, Fung-Sing; Jusko, William J.

2014-01-01

Summary The immunosuppressive interactions of calcium channel antagonists [diltiazem (Dil), verapamil (Ver) and nifedipine (Nif)], with corticosteroids [methylprednisolone (Mpl), prednisolone (Prd)], and macrolides [tacrolimus (Tac) and sirolnnus (Sir)] were examined in human whole blood lymphocyte cultures. Gender-related differences in responses in the interactions between these drug classes were studied using blood from 6 males and 6 females. The nature and intensity of interactions were determined using an extended Loewe additivity model. All immunosuppressants exhibited higher potency than the calcium channel antagonists with mean IC50 values of: Dil (mM)Ver (mM)Nif (mM)Mpl (nM)Prd (nM)Tac (nM)Sir (nM)Male13541.921312.118.6150327Female11431.847.44.68.8111106 Gender-related differences in responses to Mpl and Prd were observed while the others were not significant. Additive interactions were found among calcium channel antagonists and corticosteroids. Significant synergistic interactions were observed between calcium channel antagonists and tacrolimus and sirolimus, although these are unlikely to be of clinical importance. These studies demonstrate diverse drug interactions in the examination of an important array of immunosuppressant drug combinations. PMID:15681895

Enhancement of oral bioavailability of atorvastatin calcium by self-emulsifying drug delivery systems (SEDDS).

PubMed

Kadu, Pawan J; Kushare, Sachin S; Thacker, Dhaval D; Gattani, Surendra G

2011-02-01

The aim of the present study was to formulate a self-emulsifying drug delivery system of atorvastatin calcium and its characterization including in vitro and in vivo potential. The solubility of atorvastatin calcium was determined in various vehicles such as Captex 355, Captex 355 EP/NF, Ethyl oleate, Capmul MCM, Capmul PG-8, Gelucire 44/14, Tween 80, Tween 20, and PEG 400. Pseudoternary phase diagrams were plotted on the basis of solubility data of drug in various components to evaluate the microemulsification region. Formulation development and screening was carried out based on results obtained from phase diagrams and characteristics of resultant microemulsion. Prepared formulations were tested for microemulsifying properties and evaluated for clarity, precipitation, viscosity determination, drug content and in vitro dissolution. The optimized formulation further evaluated for particle size distribution, zeta potential, stability studies and in vivo potential. In vivo performance of the optimized formulation was evaluated using a Triton-induced hypercholesterolemia model in male Albino Wistar rats. The formulation significantly reduced serum lipid levels as compared with atorvastatin calcium. Thus studies illustrated the potential use for the delivery of hydrophobic drug such as atorvastatin calcium by oral route.

Application of laser ablation multicollector inductively coupled plasma mass spectrometry for the measurement of calcium and lead isotope ratios in packaging for discriminatory purposes.

PubMed

Santamaria-Fernandez, Rebeca; Wolff, Jean-Claude

2010-07-30

The potential of high-precision calcium and lead isotope ratio measurements using laser ablation coupled to multicollector inductively coupled plasma mass spectrometry (LA-MC-ICP-MS) to aid distinction between four genuine and five counterfeit pharmaceutical packaging samples and further classification of counterfeit packaging samples has been evaluated. We highlight the lack of reference materials for LA-MC-ICP-MS isotope ratio measurements in solids. In this case the problem is minimised by using National Institute of Standards and Technology Standard Reference Material (NIST SRM) 915a calcium carbonate (as solid pellets) and NIST SRM610 glass disc for sample bracketing external standardisation. In addition, a new reference material, NIST SRM915b calcium carbonate, has been characterised in-house for Ca isotope ratios and is used as a reference sample. Significant differences have been found between genuine and counterfeit samples; the method allows detection of counterfeits and aids further classification of packaging samples. Typical expanded uncertainties for measured-corrected Ca isotope ratio values ((43)Ca/(44)Ca and (42)Ca/(44)Ca) were found to be below 0.06% (k = 2, 95% confidence) and below 0.2% for measured-corrected Pb isotope ratios ((207)Pb/(206)Pb and (208)Pb/(206)Pb). This is the first time that Ca isotope ratios have been measured in packaging materials using LA coupled to a multicollector (MC)-ICP-MS instrument. The use of LA-MC-ICP-MS for direct measurement of Ca and Pb isotopic variations in cardboard/ink in packaging has definitive potential to aid counterfeit detection and classification. Copyright 2010 John Wiley & Sons, Ltd.

Pinoresinol-4,4'-di-O-beta-D-glucoside from Valeriana officinalis root stimulates calcium mobilization and chemotactic migration of mouse embryo fibroblasts.

PubMed

Do, Kee Hun; Choi, Young Whan; Kim, Eun Kyoung; Yun, Sung Ji; Kim, Min Sung; Lee, Sun Young; Ha, Jung Min; Kim, Jae Ho; Kim, Chi Dae; Son, Beung Gu; Kang, Jum Soon; Khan, Ikhlas A; Bae, Sun Sik

2009-06-01

Lignans are major constituents of plant extracts and have important pharmacological effects on mammalian cells. Here we showed that pinoresinol-4,4'-di-O-beta-D-glucoside (PDG) from Valeriana officinalis induced calcium mobilization and cell migration through the activation of lysophosphatidic acid (LPA) receptor subtypes. Stimulation of mouse embryo fibroblast (MEF) cells with 10 microM PDG resulted in strong stimulation of MEF cell migration and the EC(50) was about 2 microM. Pretreatment with pertussis toxin (PTX), an inhibitor of G(i) protein, completely blocked PDG-induced cell migration demonstrating that PDG evokes MEF cell migration through the activation of the G(i)-coupled receptor. Furthermore, pretreatment of MEF cells with Ki16425 (10 microM), which is a selective antagonist for LPA(1) and LPA(3) receptors, completely blocked PDG-induced cell migration. Likewise, PDG strongly induced calcium mobilization, which was also blocked by Ki16425 in a dose-dependent manner. Prior occupation of the LPA receptor with LPA itself completely blocked PDG-induced calcium mobilization. Finally, PDG-induced MEF cell migration was attenuated by pretreatment with a phosphatidylinositol 3-kinase (PI3K) inhibitor such as LY294002. Cells lacking downstream mediator of PI3K such as Akt1 and Akt2 (DKO cells) showed loss of PDG-induced migration. Re-expression of Akt1 (but not Akt2) completely restored PDG-induced DKO cell migration. Given these results, we conclude that PDG is a strong inducer of cell migration. We suggest that the pharmacological action of PDG may occur through the activation of an LPA receptor whereby activation of PI3K/Akt signaling pathway mediates PDG-induced MEF cell migration.

The Incredible, Embryological Egg: Calcium and Strontium Isotopes Recapitulate Ontogeny

NASA Astrophysics Data System (ADS)

Gordon, G. W.; Skulan, J. L.

2011-12-01

Embryological development reflects evolutionary history. Understanding the processes of fetal growth is important for curing human birth defects and predicting damage to ecosystems from environmental insults. Tracing enzymatic and hormonal gradients during development, and correlating them to genetic cues dominate modern embryology. Previous work done tracing the mass transfer of elements has generally been limited to isotope spikes in vitro. Natural mass-dependent Ca and Sr isotopic ratios and radiogenic Sr isotopes have the potential to reveal both source and biochemical mechanism information about processes in vivo, but have not previously been extensively explored. The process when a hen lays a fertilized egg that becomes a chick includes formation and dissolution of calcium phosphate (bone) and calcium carbonate (shell). Skulan and DePaolo (1999) showed that chickens have 2% δ44/42Ca between a hen's bones and an egg white; this span represents more than 80% of the entire range of natural Ca isotope variation and illustrates there is significant variation to investigate. A striking feature of archosaurian development that also occurs in many mammals, including humans, is mass transfer of calcium from mother to embryo. The yolk of the domestic hen matures over 7-9 days, but the albumen, shell membranes and shell form in less than 20 hours. Domestic laying hens are at the physiological limit of egg production and selective breeding is no longer an effective method of increasing egg production. 60-75% of the shell's ~1.5 g of calcium comes from dietary sources, while 25-40% comes from the hen's medullary bone. Medullary bone is spicules formed in the marrow of long bones, and is a store of dietary calcium rapidly available for eggshell secretion. During in ovo development, the embryo's skeleton is formed from calcium in the yolk and by bulk dissolution of the eggshell's inner aspect via carbonic anhydrase in a process that has an effect on bone density similar to that caused by osteoporosis in humans. For both mass-dependent Ca and Sr isotopes, the isotopic value of the albumen is the highest natural value yet measured. The offset between the δ88/86Sr values of the albumen and shell is 0.45%, less than half that of the δ44/42Ca offset value (1.29%), as predicted by the relative mass differences. However, the yolk is 0.35% heavier than the shell in δ44/42Ca but 0.70% lighter in δ88/86Sr. In addition, the 87Sr/86Sr value of the shell (0.70854 ±0.000012, 2σ) is statistically the same as the albumen (0.70856 ±0.000018), but slightly offset from the yolk (0.70830 ±0.000014). The apparent decoupling of Ca and Sr, and the radiogenic offset between yolk and shell, may reflect differences in the residence time of calcium and strontium in different reproductive organs, as well as the contribution of medullary bone to shell formation. In addition, it may also reflect differential discrimination against Sr versus Ca in oviduct and uterus. Further studies could extend to thinning eggshells in wild avian populations, biochemical mechanisms of bone formation, and the mechanism of strontium ranelate in the treatment of osteoporosis.

Calcium isotopes in fossil bones and teeth — Diagenetic versus biogenic origin

NASA Astrophysics Data System (ADS)

Heuser, Alexander; Tütken, Thomas; Gussone, Nikolaus; Galer, Stephen J. G.

2011-06-01

We present the first systematic study of Ca isotopes ( δ44/40Ca) in Late Triassic to Late Cretaceous dinosaur bones and teeth (enamel and dentin) from sympatric herbivorous and carnivorous dinosaurs. The samples derive from five different localities, and data from embedding sediments are also presented. Additional δ44/40Ca in skeletal tissues from modern reptiles and birds (avian dinosaurs) were measured for comparison in order to examine whether the original Ca isotopic composition in dinosaur skeletal apatite was preserved or might have changed during the diagenesis and fossilization process. δ44/40Ca of fossil skeletal tissues range from -1.62‰ ( Tyrannosaurus rex enamel) to +1.08‰ ( Brachiosaurus brancai bone), while values in modern archosaur bones and teeth range from -1.63‰ (caiman enamel) to -0.37‰ (ostrich bone). The average δ44/40Ca of the three types of fossil skeletal tissue analyzed - bone, dentin and enamel - show some systematic differences: while δ44/40Ca in bone exhibits the highest values, while δ44/40Ca in enamel has the lowest values, and dentin δ44/40Ca falls in between. Values of δ44/40Ca in the remains of herbivorous dinosaurs (0.1-1.1‰) are generally higher than those of bones of modern mammalian herbivores (-2.6‰ to -0.8‰) and from modern herbivorous archosaurs, which exhibit intermediate δ44/40Ca (-0.8‰ to -0.4‰). These systematic isotopic shifts may reflect physiological differences between dinosaurs, mammals and reptiles representing different taxonomic groups of vertebrates. Systematic offsets in skeletal apatite δ44/40Ca between herbivorous and carnivorous dinosaurs are not obvious, indicating a lack of a clear-cut Trophic Level Effect (TLE) shift between herbivores and carnivores in dinosaurs. This observation can be explained if the carnivorous dinosaurs in this study fed mainly on soft tissues from their prey and did not ingest hard (calcified) tissue to much extent. The most striking indication that the primary δ44/40Ca is actually preserved in most of the fossil teeth is a difference in δ44/40Ca of about 0.35 ± 0.10‰ (1SD) between dentin and enamel, based upon 11 of 16 analyzed dentin-enamel pairs. This difference is close to that found in modern reptiles (0.28 ± 0.05‰), and strongly suggests that this tell-tale signature is a primary feature of the fossilized dinosaur material as well. Furthermore, simple mass balance calculations show that changes of the original δ44/40Ca in bones and teeth by diagenetically-formed calcium-bearing minerals are either small or would require implausible high original δ44/40Ca values in the skeletal apatite.

Coronary calcium in systemic lupus erythematosus is associated with traditional cardiovascular risk factors, but not with disease activity.

PubMed

Kiani, Adnan N; Magder, Laurence; Petri, Michelle

2008-07-01

Cardiovascular disease is a major cause of morbidity and mortality in systemic lupus erythematosus (SLE). The frequency of both subclinical and clinically evident atherosclerosis is greatly increased over healthy controls. We assessed cardiovascular risk factors present in patients with SLE at the baseline visit in a statin intervention trial and their correlation with coronary calcium. Coronary calcium was measured by helical computed tomography (continuous volumetric data acquisition in a single breath-hold) in 200 patients with SLE enrolled in the Lupus Atherosclerosis Prevention Study. Patients had a mean age of 44.3 +/- 11.4 years and were 92% women, 61% Caucasian, 34% African American, 2% Asian, and 2% Hispanic. Coronary calcium was found in 43%. In univariate analysis, coronary calcification was associated with age (p = 0.0001), hypertension (p = 0.0008), body mass index (BMI; p = 0.03), erythrocyte sedimentation rate (ESR; p = 0.03), anti-dsDNA (p = 0.067), and lipoprotein(a) (p = 0.03). Homocysteine (p = 0.050), high-sensitivity C-reactive protein (hsCRP; p = 0.053), and LDL (p = 0.048) had a stronger association when considered as quantitative predictors. In a multiple logistic regression model, only age (p 100. Based on a multiple logistic regression model, only age (p = 0.0017) and diabetes mellitus (p = 0.019) remained significant independent predictors of coronary calcium > 100. Inflammation, measured as ESR or hsCRP, is associated with coronary calcium only in univariate analyses. Age, BMI, and diabetes mellitus are more important associates of coronary calcium in SLE than inflammatory markers and SLE clinical activity.

The Positive Inotropic Effect of Pyruvate Involves an Increase in Myofilament Calcium Sensitivity

PubMed Central

Torres, Carlos A. A.; Varian, Kenneth D.; Canan, Cynthia H.; Davis, Jonathan P.; Janssen, Paul M. L.

2013-01-01

Pyruvate is a metabolic fuel that is a potent inotropic agent. Despite its unique inotropic and antioxidant properties, the molecular mechanism of its inotropic mechanism is still largely unknown. To examine the inotropic effect of pyruvate in parallel with intracellular calcium handling under near physiological conditions, we measured pH, myofilament calcium sensitivity, developed force, and calcium transients in ultra thin rabbit heart trabeculae at 37 °C loaded iontophoretically with the calcium indicator bis-fura-2. By contrasting conditions of control versus sarcoplasmic reticulum block (with either cyclopiazonic acid and ryanodine or with thapsigargin) we were able to characterize and isolate the effects of pyruvate on sarcoplasmic reticulum calcium handling and developed force. A potassium contracture technique was subsequently utilized to assess the force-calcium relationship and thus the myofilament calcium sensitivity. Pyruvate consistently increased developed force whether or not the sarcoplasmic reticulum was blocked (16.8±3.5 to 24.5±5.1 vs. 6.9±2.6 to 12.5±4.4 mN/mm2, non-blocked vs. blocked sarcoplasmic reticulum respectively, p<0.001, n = 9). Furthermore, the sensitizing effect of pyruvate on the myofilaments was demonstrated by potassium contractures (EC50 at baseline versus 20 minutes of pyruvate infusion (peak force development) was 701±94 vs. 445±65 nM, p<0.01, n = 6). This study is the first to demonstrate that a leftward shift in myofilament calcium sensitivity is an important mediator of the inotropic effect of pyruvate. This finding can have important implications for future development of therapeutic strategies in the management of heart failure. PMID:23691074

Calcium/vitamin D supplementation and coronary artery calcification in the Women's Health Initiative.

PubMed

Manson, JoAnn E; Allison, Matthew A; Carr, J Jeffrey; Langer, Robert D; Cochrane, Barbara B; Hendrix, Susan L; Hsia, Judith; Hunt, Julie R; Lewis, Cora E; Margolis, Karen L; Robinson, Jennifer G; Rodabough, Rebecca J; Thomas, Asha M

2010-07-01

Coronary artery calcified plaque is a marker for atheromatous plaque burden and predicts future risk of cardiovascular events. The relationship between calcium plus vitamin D (calcium/D) supplementation and coronary artery calcium (CAC) has not been previously assessed in a randomized trial setting. We compared CAC scores after trial completion between women randomized to calcium/vitamin D supplementation and women randomized to placebo. In an ancillary substudy of women randomized to calcium carbonate (1,000 mg of elemental calcium daily) plus vitamin D3 (400 IU daily) or placebo, nested within the Women's Health Initiative trial of estrogen among women who underwent hysterectomy, we measured CAC with cardiac CT in 754 women aged 50 to 59 years at randomization. Imaging for CAC was performed at 28 of 40 centers after a mean of 7 years of treatment, and scans were read centrally. CAC scores were measured by a central reading center with masking to randomization assignments. Posttrial CAC measurements were similar in women randomized to calcium/D supplementation and those receiving placebo. The mean CAC score was 91.6 for women receiving calcium/D and 100.5 for women receiving placebo (rank test P value = 0.74). After adjustment for coronary risk factors, multivariate odds ratios for increasing CAC score cutpoints (CAC >0, > or =10, and > or =100) for calcium/D versus placebo were 0.92 (95% CI, 0.64-1.34), 1.29 (0.88-1.87), and 0.90 (0.56-1.44), respectively. Corresponding odds ratios among women with a 50% or higher adherence to study pills and for higher levels of CAC (>300) were similar. Treatment with moderate doses of calcium plus vitamin D3 did not seem to alter coronary artery calcified plaque burden among postmenopausal women. Whether higher or lower doses would affect this outcome remains uncertain.

Hypocalcaemia and permanent hypoparathyroidism after total/bilateral thyroidectomy in the BAETS Registry

PubMed Central

2017-01-01

The UK Registry of Endocrine and Thyroid Surgeons (UKRETS) has been operated by the British Association of Endocrine and Thyroid Surgeons (BAETS) and Dendrite Clinical Systems Ltd. in a web-based electronic format since 2004. Data on over 90,000 endocrine procedures have been collected to date. Analysis of those cases undergoing bilateral thyroid resections in the interval July 2010 to June 2015 demonstrates that hypocalcaemia remains the commonest complication of thyroid surgery. After first-time total thyroidectomy, 23.6% of patients develop hypocalcaemia, defined as a serum calcium <2.10 mmol/L (or <1.20 mmol/L ionized calcium) on the first post-operative day. Most require treatment with calcium +/− vitamin D supplements, with around 38% of all patients being treated by the time of discharge from the index admission. By 6 months post-operative, 7.3% of patients remain on calcium/vitamin D supplements, reflecting persistent (though not necessarily permanent) hypoparathyroidism. Risk factors for persistent hypocalcaemia are principally concomitant level VI lymph node dissection [odds ratio (OR) =2.73]; re-operative surgery (OR =1.44); and inter-surgeon variation. PMID:29322024

Heterogeneity in iota-carrageenan molecular structure: insights for polymorph II→III transition in the presence of calcium ions

DOE Office of Scientific and Technical Information (OSTI.GOV)

Janaswamy, Srinivas; Chandrasekaran, Rengaswami

2008-06-24

Iota-carrageenan is used in pharmaceutical and food applications due to its ability to complex with other hydrocolloids and proteins. Six distinct cation dependent allomorphs, consistent with its versatile functionality, have so far been observed in the solid state. In this contribution, X-ray structural details of calcium iota-carrageenan (form III) are reported. The polysaccharide retains the half-staggered, parallel, 3-fold, right-handed double helix stabilized by interchain hydrogen bonds from O-2H and O-6H in the Galp units. Results show that there are four helices, rather than one in I or three in II, organized in a larger pseudo-trigonal unit cell of dimensions a=27.44,more » c=13.01 A, and gamma=120 degrees . The four helices have similar core structures, but their sulfate group orientations are quite different. Fifteen calcium ions and 64 water molecules hold the helices together and promote helix-helix interactions. The results portray how the helices would shuffle around in an orchestrated manner to yield calcium iota-carrageenan III from II.« less

Increased water hardness and magnesium levels may increase occurrence of urolithiasis in cows from the Burdur region (Turkey).

PubMed

Sahinduran, S; Buyukoglu, T; Gulay, M S; Tasci, F

2007-08-01

Objectives of the study were to measure water hardness in Burdur, and to establish its possible association with urolithiasis in cattle. Water samples were obtained from different stables (n = 15). Water hardness and the concentrations of potassium, calcium, magnesium, sodium, iron, zinc, manganese and copper ions were calculated from these water samples. Total hardness of the samples (mean 285 ppm) exceeded the standards and the water was characterized by high content of magnesium ions. Kidneys (n = 500) were collected randomly from slaughterhouses and examined for urolithiasis. Urolithiasis was observed in 102 kidneys (20.4%). The weights of the stones were between 0.02 and 237.44 g and the colour varied from white to brown. The calculi collected had various shapes and composed of calcium apatite (42.45%), struvite (20.15%), magnesium carbonate (15.15%), calcium carbonate (12.12%), and calcium phosphate cystine (10.13%). It was concluded that high water hardness with high magnesium ion concentrations in water may contribute to urolithiasis and needs to be investigated further in future studies.

Structural characterization of rondorfite, calcium silica chlorine mineral containing magnesium in tetrahedral position [MgO4]6-, with the aid of the vibrational spectroscopies and fluorescence.

PubMed

Dulski, M; Bulou, A; Marzec, K M; Galuskin, E V; Wrzalik, R

2013-01-15

Raman and infrared spectra of rondorfite Ca8Mg(SiO4)4Cl2, a calcium chlorosilica mineral containing magnesium in tetrahedral position, has been studied in terms of spectra-structure relations. Raman spectra have been measured at different excited laser lines: 780 nm, 532 nm, 488 nm and 457 nm. This mineral is characterized by a single sharp intense Raman band at 863 cm(-1) assigned to the ν1 [SiO4]4- (Ag) symmetric stretching mode in the magnesiosilicate pentamer. Due to symmetry restriction the other Raman bands have a small intensity. Two Raman bands observed at 564 cm(-1) and 526 cm(-1) are associated simultaneously with ν4 [MgO4]6- and ν4 [SiO4]4- symmetric and antisymmetric modes where magnesium occurs in the tetrahedral configuration. The weak bands at 422 cm(-1) and 386 cm(-1) are associated with the ν2 bending mode of CaO6 in octahedral configuration, respectively. Moreover the infrared spectrum shows very weak bands associated with the hydroxyl group and/or water molecule. Additionally, the strong fluorescence phenomenon was observed and related to the presence of chlorine atoms, magnesium Mg2+ ions in atypical configuration or point defects. Copyright © 2012 Elsevier B.V. All rights reserved.

MULTIPLE POWER DENSITY WINDOWS AND THEIR POSSIBLE ORIGIN

EPA Science Inventory

We have previously reported that in vitro exposure of chick forebrain tissue to 50-Mz radiofrequency (RF) radiation, amplitude modulated (AM) at 16 Hz, would enhance the efflux of calcium ions only within two power density ranges: one spanning from 1.44 to 1.67 mW/cm2, and the ot...

On-The-Move Nutrient Delivery System (NDS): User Acceptability of Rotary Flow Control Version

DTIC Science & Technology

2009-04-01

Following: Salt, Sodium Citrate, Monopotassium Phosphate, Sodium Benzoate , Potassium Sorbate, FD & C Yellow #5. Faslln,,, Flow Mallifold 126.00 g (4.44 oz...Fat Cholesterol Sodium 440mg Potassium Total Carbohydrate Dietary Fiber Sugars Protein Vitamin A Vitamin C Calcium lron Phosphorus 260 o Og Og Omg 18

Effects of FGD-gypsum, used-wallboard and calcium sulfate on corn and soybean root growth

USDA-ARS?s Scientific Manuscript database

Flue gas desulfurization (FGD)-gypsum production has increased 44 percent from 2007 to 2008. The major use of FGD-gypsum today is in the wallboard industry. Reduction in the construction, however, reduces the demand for wallboard. Agriculture could become the second largest user of FGD-gypsum. F...

Indian Summer Monsoon dynamics during Termination II and MIS 5e

NASA Astrophysics Data System (ADS)

Magiera, Matthias; Erhardt, Andrea M.; Hartland, Adam; Kwiecien, Ola; Cheng, Hai; Immenhauser, Adrian; Turchyn, Alexandra; Breitenbach, Sebastian F. M.

2017-04-01

The interpretation of speleothem oxygen isotope ratios (δ18O) as proxy for Indian Summer Monsoon (ISM) dynamics is ambiguous, due to multiple influencing factors. Here we combine δ18O and calcium isotope δ44Ca analyses with elemental data to delineate regional shifts in moisture source, local rainfall amount, and changes in ISM intensity and length during Termination II and MIS 5e. Oxygen isotope ratios reflect a mixed signal of moisture source dynamics and rainfall amount; δ44Ca and Mg/Ca ratios are interpreted as proxies for local effective moisture and prior calcite precipitation (PCP) in the epikarst. The age of stalagmite MAW-3 from Mawmluh Cave, NE India, is constraint by six U-series dates. 108 samples, obtained at 0.4 mm resolution from the 70 mm long speleothem sample, have been analysed for δ18O, δ44Ca and Mg/Ca. Oxygen isotope ratios were measured on a ThermoFisher Scientific MAT 253 at Ruhr-University Bochum. Elemental ratios were measured on a quadrupole ICP-MS at Waikato University. Calcium isotope ratios were analyzed on a ThermoFisher Scientific Triton at University of Cambridge. MAW-3 grew from 136 kyrs BP to 96 kyrs BP, covering Termination II and MIS 5e. Oxygen isotope values are high (ca. +0.91 ‰) during Termination II, reach a minimum during MIS 5e (-3.5 ‰), and rise again to -0.2 ‰ at the end of MIS 5e. Calcium isotope ratios range from -0.32 ‰ to -0.70 ‰ and show a positive correlation (R2= 0.7) with δ18O. High δ18O values during Termination II reflect reduced atmospheric circulation and/or a proximal moisture source (Bay of Bengal), implying lowered ISM intensity. A positive correlation of δ18O with δ44Ca suggests concurrent changes of moisture source location and local rainfall amount, with a proximal moisture source and reduced effective rainfall during periods of weak ISM. Elevated Mg/Ca ratios at such intervals corroborate PCP occurrence, which reflects dry conditions. The beginning of MIS 5e (ca. 132 kyrs BP) is marked by a rapid change to lower δ18O and δ44Ca, suggesting increased local infiltration with increasing ISM rainfall, and a concurrent change to a more distal moisture source. The MAW-3 multi-proxy record compares well with reconstructions from China and northern India, the latter being more depleted, due to Rayleigh fractionation. We suggest that multi-proxy analyses of δ18O, δ44Ca and Mg/Ca greatly help to delineate regional circulation pattern and local effective moisture dynamics in monsoonal settings.

Desensitizing toothpaste versus placebo for dentin hypersensitivity: a systematic review and meta-analysis.

PubMed

Bae, Ji-Hyun; Kim, Young-Kyun; Myung, Seung-Kwon

2015-02-01

The aim is to assess the effect of desensitizing toothpaste on dentin hypersensitivity. We searched PubMed, CENTRAL, and Embase on December 20, 2013. Out of the 626 articles searched, a total of 31 randomized controlled clinical trials were included. The Standardized mean differences (SMD) for potassium-containing toothpaste (n = 8) was -1.28 (95% Confidence interval (CI) -2.05 to -0.51; I(2) = 93%); Stannous fluoride- (n = 6) was -1.37 (95% CI, -2.30 to -0.44; I(2) = 95%); Potassium and stannous fluoride- (n = 3) was -2.50 (95% CI, -4.10 to -0.91; I(2) = 95%); Calcium sodium phosphosilicate- (n = 4) was -2.36 (95% CI, -3.72 to -1.00; I(2) = 92%); Arginine- (n = 8) was -3.25 (95% CI, -3.87 to -2.63; I(2) = 86%). The desensitizing effect was favoured in the intervention group treated with potassium-, stannous fluoride-, potassium and stannous fluoride-, calcium sodium phosphosilicate-, and arginine-containing toothpaste compared to placebo. Whereas, strontium-containing toothpaste (SMD, 0.05; 95% CI, -0.34 to 0.44; I(2) = 64%) was found to have no statistically significant desensitizing effect in the meta-analysis of four studies. The study reports that there is sufficient evidence to support the use of potassium-, stannous fluoride-, potassium and stannous fluoride-, calcium sodium phosphosilicate-, and arginine-containing desensitizing toothpastes for dentin hypersensitivity, but not the use of strontium-containing desensitizing toothpaste. © 2014 John Wiley & Sons A/S. Published by John Wiley & Sons Ltd.

Mass dependence of calcium isotope fractionations in crown-ether resin chromatography.

PubMed

Fujii, Yasuhiko; Nomura, Masao; Kaneshiki, Tositaka; Sakuma, Yoichi; Suzuki, Tatsuya; Umehara, Saori; Kishimoto, Tadahumi

2010-06-01

Benzo 18-crown-6-ether resin was synthesised by the phenol condensation polymerisation process in porous silica beads, of which particle diameter was ca 60micro Calcium adsorption chromatography was performed with the synthesised resin packed in a glass column. The effluent was sampled in fractions, and the isotopic abundance ratios of (42)Ca, (43)Ca, (44)Ca, and (48)Ca against (40)Ca were measured by a thermo-ionisation mass spectrometer. The enrichment of heavier calcium isotopes was observed at the front boundary of calcium adsorption chromatogram. The mass dependence of mutual separation of calcium isotopes was analysed by using the three-isotope-plots method. The slopes of three-isotope-plots indicate the relative values of mutual separation coefficients for concerned isotopic pairs. The results have shown the normal mass dependence; isotope fractionation is proportional to the reduced mass difference, (M - M')/MM', where M and M' are masses of heavy and light isotope, respectively. The mass dependence clarifies that the isotope fractionations are originated from molecular vibration. The observed separation coefficient epsilon is 3.1x10(-3) for the pair of (40)Ca and (48)Ca. Productivity of enriched (48)Ca by crown-ether-resin was discussed as the function of the separation coefficient and the height equivalent to the theoretical plate.

Serum calcium changes and risk of type 2 diabetes mellitus in Asian population.

PubMed

Suh, Sunghwan; Bae, Ji Cheol; Jin, Sang-Man; Jee, Jae Hwan; Park, Mi Kyoung; Kim, Duk Kyu; Kim, Jae Hyeon

2017-11-01

We examined the association between changes in serum calcium levels with the incidence of type 2 diabetes mellitus (T2DM) in apparently healthy South Korean subjects. A retrospective longitudinal analysis was conducted with subjects who had participated in comprehensive health check-ups at least four times over a 7-year period (between 2006 and 2012). In total, 23,121 subjects were categorized into tertiles based on changes in their albumin-adjusted serum calcium levels. Multivariate Cox regression models were fitted to assess the association between changes in serum calcium levels during follow-up and the relative risk of diabetes incidence. After a median follow-up of 57.4months, 1,929 (8.3%) new cases of T2DM occurred. Simple linear regression analysis showed serum calcium level changes correlated positively with changes in HbA1c and fasting plasma glucose (FPG) levels (B=5.72, p<0.001 for FPG; B=0.13, p<0.001 for HbA1c). An increase in albumin-adjusted serum calcium levels during follow-up was related to an increased risk of T2DM. After adjustment for potential confounders, the risk of T2DM was 1.6 times greater for subjects whose albumin-adjusted serum calcium levels were in the highest change tertile during follow-up than for subjects whose levels were in the lowest tertile (HR 1.65, 95% CI 1.44-1.88, P<0.001). The elevation of albumin-adjusted serum calcium levels was associated with an increased risk of T2DM, independent of baseline glycemic status. Copyright © 2017 Elsevier B.V. All rights reserved.

A Comparative Study of Ion Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin

PubMed Central

Dhirawani, Rajesh B; Marya, Jayant; Dhirawani, Vrinda; Kumar, Vijayendra

2017-01-01

Aim The aim of this study was to evaluate the diffusion ability of ions through dentinal tubules of different nonalcoholic calcium hydroxide-containing herbal pastes and compare it with the calcium hydroxide paste prepared with saline. Materials and methods A total of 36 single-rooted premolar teeth were used in this study. The tooth crowns were removed and the root canals were prepared. Depending on the vehicle to be used for preparing calcium hydroxide pastes, six groups were made: Group I: Ca(OH)2 saline paste (control group), group II: Ca(OH)2 papaya latex paste, group III: Ca(OH)2 coconut water paste, group IV: Ca(OH)2 Ashwagandha (Withania somnifera) paste, group V: Ca(OH)2 Tulsi (Ocimum tenuiflorum) paste, and group VI: Ca(OH)2 garlic (Allium sativum) paste. After biomechanical preparation, calcium hydroxide herbal paste dressings were applied and sealed with resin-based cement. The teeth were placed in containers with deionized water, and the pH of the water was measured at regular intervals over 3, 24, 72, and 168 hours. Results We observed that all herbal pastes allowed the diffusion of ions, but pastes prepared with Ashwagandha and papaya latex showed more ion diffusion after 168 hours and marked increase in pH, depicting better support for calcium hydroxide action. Conclusion We conclude that Ashwagandha and papaya latex allow better diffusion of calcium hydroxide through den-tinal tubules, thus enhancing its action, and advise its use as a vehicle for placing intracanal medicament. How to cite this article Dausage P, Dhirawani RB, Marya J, Dhirawani V, Kumar V. A Comparative Study of Ion Diffusion from Calcium Hydroxide with Various Herbal Pastes through Dentin. Int J Clin Pediatr Dent 2017;10(1):41-44. PMID:28377654

Parallel studies of His-DTrp-Ala-Trp-DPhe-Lys-NH2 and human pancreatic growth hormone-releasing factor-44-NH2 in rat primary pituitary cell monolayer culture.

PubMed

Sartor, O; Bowers, C Y; Chang, D

1985-03-01

His-DTrp-Ala-Trp-DPhe-Lys-NH2 (GH-RP-6) is a synthetic hexapeptide that specifically releases GH both in vivo and in vitro in pituitary incubates. In this study, for the first time, GH-RP-6 was studied in primary pituitary cell monolayer culture. Parallel studies were performed with human pancreatic GH-releasing factor-44 (hpGRF-44). Culture conditions optimal for GH-RP-6 were not optimal for hpGRF-44. Both peptides released GH in a dose- and time-dependent manner. In this assay system, the ED50 for GH-RP-6 was 9 nM, and the ED50 for hp-GRF-44 was 1.6 nM. Calcium-blocking agents inhibited the GH responses of both peptides as well as basal GH release. Pretreatment with GH-RP-6 decreased the subsequent response to both GH-RP-6 and hpGRF-44. hpGRF-44 down regulated itself but not GH-RP-6. Rat sera potentiated the GH response of hpGRF-44 but not that of GH-RP-6. GH-RP-6 and hpGRF-44 GH responses were additive. These results suggest that GH-RP-6 and hpGRF-44 stimulate GH release via different somatotroph receptors.

First-principles Calculations of Equilibrium Calcium Isotope Fractionation among Ca-bearing Minerals

NASA Astrophysics Data System (ADS)

Zhou, C.; Wang, W.; Kang, J.; Wu, Z.; Huang, F.

2016-12-01

Calcium isotope fractionation factors of Ca-bearing minerals are investigated with the first principle calculations based on density functional theory (DFT). The sequence of heavy Ca isotope enrichment is forsterite > grossular > butschliite > lime > fluorite > tremolite diopside > anhydrite dolomite titanite > anorthite > perovskite gehlenite aragonite richterite > akermanite > oldhamite. This order is consistent with variation of Ca-O bond lengths, indicating that Ca-O bond energy plays an overwhelming role on the fractionations of Ca isotopes. Our study provides important insights into the Ca isotopic data of meteorites. Our calculation predicts that oldhamites (CaS) are enriched in light Ca isotopes relative to silicate phase if they are in equilibrium, contrast with the observations in Valdes et al (2014). Therefore, oldhamite and silicate phase in the meteorites should be in disequilibrium for Ca isotopes. Our results can also be used to understand Ca isotopic composition of the Moon. Δ44/40Ca between olivine (with CaO content of 2.48 wt%) and diopside is up to 0.41‰ and Δ44/40Cagrossular-diopside is 0.26‰ at 1500K. Feng et al. (2014) calculated that Δ44/40Ca between opx with CaO content of 1.74 wt% and cpx is about 0.27‰ at 1500 K. According to the Lunar Magma Ocean (LMO) model, the modern Moon is chemically stratified (Snyder et al., 1992; Elardo et al., 2011). Assuming that the lower cumulate and upper residual melt are in isotopic equilibrium during the evolution of Lunar Magma Ocean where the cumulate may be mainly composed of olivine and orthopyroxene or garnet/spinel, δ44/40Ca of the Moon could be underestimated by 0.05‰ to 0.25‰ if the shallow lunar samples are used to represent the bulk Moon.

Testing the chondrule-rich accretion model for planetary embryos using calcium isotopes

NASA Astrophysics Data System (ADS)

Amsellem, Elsa; Moynier, Frédéric; Pringle, Emily A.; Bouvier, Audrey; Chen, Heng; Day, James M. D.

2017-07-01

Understanding the composition of raw materials that formed the Earth is a crucial step towards understanding the formation of terrestrial planets and their bulk composition. Calcium is the fifth most abundant element in terrestrial planets and, therefore, is a key element with which to trace planetary composition. However, in order to use Ca isotopes as a tracer of Earth's accretion history, it is first necessary to understand the isotopic behavior of Ca during the earliest stages of planetary formation. Chondrites are some of the oldest materials of the Solar System, and the study of their isotopic composition enables understanding of how and in what conditions the Solar System formed. Here we present Ca isotope data for a suite of bulk chondrites as well as Allende (CV) chondrules. We show that most groups of carbonaceous chondrites (CV, CI, CR and CM) are significantly enriched in the lighter Ca isotopes (δ 44 / 40 Ca = + 0.1 to + 0.93 ‰) compared with bulk silicate Earth (δ 44 / 40 Ca = + 1.05 ± 0.04 ‰, Huang et al., 2010) or Mars, while enstatite chondrites are indistinguishable from Earth in Ca isotope composition (δ 44 / 40 Ca = + 0.91 to + 1.06 ‰). Chondrules from Allende are enriched in the heavier isotopes of Ca compared to the bulk and the matrix of the meteorite (δ 44 / 40 Ca = + 1.00 to + 1.21 ‰). This implies that Earth and Mars have Ca isotope compositions that are distinct from most carbonaceous chondrites but that may be like chondrules. This Ca isotopic similarity between Earth, Mars, and chondrules is permissive of recent dynamical models of planetary formation that propose a chondrule-rich accretion model for planetary embryos.

The timing of cortical granule fusion, content dispersal, and endocytosis during fertilization of the hamster egg: an electrophysiological and histochemical study.

PubMed

Kline, D; Stewart-Savage, J

1994-03-01

To determine the temporal relationship between cortical granule exocytosis and the repetitive calcium transients, which are characteristic of mammalian fertilization, we monitored membrane addition from exocytosis during fertilization of hamster eggs. Continuous measurement of membrane capacitance by applying a 3.1-nA alternating current at 375 Hz showed addition of cortical granule membrane. Simultaneous measurement of membrane potential revealed each calcium transient by the appearance of transient hyperpolarizing responses due to calcium-activated potassium channels in the egg. The initial membrane capacitance of the eggs averaged 736 +/- 44 pF (mean +/- SD; n = 7) and an increase in capacitance of 61 +/- 19 pF occurred within 4 sec of the start of the first hyperpolarizing response (HR) after fertilization. Immediately after the first increase in capacitance there was a gradual decline in membrane capacitance in all eggs and in five/seven eggs the capacitance returned to the unfertilized level in 7.8 +/- 4.4 min. The gradual decline in capacitance after the first increase indicated endocytosis, which was confirmed by the internalization of fluorescently labeled dextran. Superimposed on the gradual decline in membrane capacitance were smaller increases in capacitance that occurred with the second and later HRs. The total increase in capacitance from the first three events averaged 72 +/- 19 pF, representing an average increase in capacitance of about 10% of the capacitance of the unfertilized egg. By labeling eggs before and after permeabilization with two different fluorochromes attached to Lens culinaris agglutinin, we demonstrate that the dispersal of the cortical granules contents does not occur immediately after exocytosis. Our results demonstrate that cortical granule exocytosis in hamster eggs is closely coupled to the periodic increases in calcium, that the contents of the cortical granules are slow to disperse, and that after exocytosis, the surface area of the egg returns to the unfertilized level because of a period of endocytosis.

Evaluation of the Heshang Cave stalagmite calcium isotope composition as a paleohydrologic proxy by comparison with the instrumental precipitation record.

PubMed

Li, Xiuli; Cui, Xueping; He, Dong; Liao, Jin; Hu, Chaoyong

2018-02-08

With their merits of precise dating and sensitivity to climate changes, laminated stalagmites are an important terrestrial archive for reconstructions of paleohydrological changes. In particular, the Ca isotope composition (δ 44/42 Ca) of the Heshang Cave stalagmite has been documented to record a precipitation decrease during the 8.2 ka event in central China. As an extension, this study directly compares near-annual resolution δ 44/42 Ca data with an instrumental precipitation record to evaluate the fidelity of δ 44/42 Ca as a paleohydrologic proxy on annual to decade timescales. Over the period 1881-2001 AD, the δ 44/42 Ca values correlate significantly with both precipitation from a nearby weather station and the dryness/wetness index in the middle Yangtze River, with a stronger correlation on decadal smoothed data. These results clearly show that the δ 44/42 Ca ratio from stalagmites is an effective proxy for paleohydrological changes on a decadal timescale. More study is encouraged to refine understanding of stalagmite Ca isotope ratios and hydrological conditions and their application in paleohydrologic reconstructions.

Circulating parathyroid hormone and calcitonin in rats after spaceflight

NASA Technical Reports Server (NTRS)

Arnaud, Sara B.; Fung, Paul; Popova, Irina A.; Morey-Holton, Emily R.; Grindeland, Richard E.

1992-01-01

Parathyroid hormone and calcithonin, two major calcium-regulating hormones, were measured in the plasma of five experimental groups of rats to evaluate postflight calcium homeostasis after the 14-day Cosmos 2044 flight. Parathyroid hormone values were slightly higher in the flight animals (F) than in the appropriate cage and diet controls (S) (44 +/- 21 vs 21 +/- 4 pg/ml, P less than 0.05), but they were the same as in the vivarium controls (V), which had different housing and feeding schedules. The difference in F and V (22 +/- 11 vs 49 +/- 16 pg/ml, P less than 0.05) was most likely due to failure of circulating calcitonin in F to show the normal age-dependent increase which was demonstrated in age-matched controls in a separate experiment. Basal values for parathyroid hormone and calcitonin were unchanged after 2 wk of hindlimb suspension, a flight simulation model, in age-matched and younger rats. From a time course experiment serum calcium was higher and parathyroid hormone lower after 4 wk than in ambulatory controls. Postflight circulating levels of parathyroid hormone appear to reflect disturbances in calcium homeostasis from impaired renal function of undetermined cause, whereas levels of calcitonin reflect depression of a normal growth process.

Perioperative indicators of hypocalcemia in total thyroidectomy: the role of vitamin D and parathyroid hormone.

PubMed

Salinger, Eric M; Moore, John T

2013-12-01

Hypocalcemia is a common complication of thyroidectomy. The aim of this study was to identify risk factors for this problem. This prospective analysis included 111 patients undergoing total or completion thyroidectomy. Preoperative vitamin D levels and postoperative day 1 parathyroid hormone levels were analyzed for their predictive effects on postoperative hypocalcemia. Patients with ionized calcium <4.4 mg/dL had significantly lower mean parathyroid hormone levels than normocalcemic patients (13.0 vs 28.4 pg/mL, P < .001). Parathyroid hormone levels were also significantly lower in symptomatic patients (11.0 vs 28.4 pg/mL, P < .001). Preoperative vitamin D level, body mass index, gender, and pathologic findings were not associated with low calcium levels or symptoms of hypocalcemia. Younger age and low postoperative parathyroid hormone levels are predictive of symptomatic hypocalcemia. A parathyroid hormone level outside of the reference range may indicate a need for more aggressive postoperative calcium supplementation and treatment with activated vitamin D. Older patients with normal postoperative parathyroid hormone levels may be safely discharged with appropriate calcium supplementation. Copyright © 2013 Elsevier Inc. All rights reserved.

The effect of crystal structure of TiO2 nanotubes on the formation of calcium phosphate coatings during biomimetic deposition

NASA Astrophysics Data System (ADS)

Liu, Yi; Kim, Sun; McLeod, John A.; Li, Jun; Guo, Xiaoxuan; Sham, Tsun-Kong; Liu, Lijia

2017-02-01

The crystallization process of bioactive calcium phosphate (CaP) species via biomimetic deposition onto anodic TiO2 nanotubes is investigated. The porous surface of nanostructured TiO2 provides an ideal substrate for CaP crystallization. The compositions of CaP coatings are studied using X-ray absorption near-edge structures (XANES) at the Ca K-edge. Using detection modes with different probing depths, both the surface of the CaP coating and the CaP-TiO2 interface are simultaneously analyzed. Calcium phosphate (CaP) species, such as hydroxyapatite (HAp), octacalcium phosphate (Ca8(HPO4)2(PO4)4·5H2O, OCP), brushite (CaHPO4·2H2O, DCPD), and amorphous calcium phosphate (ACP), are found in the CaP coatings. TiO2 nanotubes of amorphous and anatase phases are comparatively studied to determine their effect on the efficiency of CaP formation and the phase transformation among CaP species in prolonged deposition time. It is found the composition of CaP coating has a strong dependency on the crystal structure of TiO2 substrate and the kinetics (deposition time).

Enhanced drug encapsulation and extended release profiles of calcium-alginate nanoparticles by using tannic acid as a bridging cross-linking agent.

PubMed

Abulateefeh, Samer R; Taha, Mutasem O

2015-01-01

Calcium alginate nanoparticles (NPs) suffer from sub-optimal stability in bio-relevant media leading to low drug encapsulation efficiency and uncontrolled release profiles. To sort out these drawbacks, a novel approach is proposed herein based on introducing tannic acid into these NPs to act as a bridging cross-linking aid agent. Calcium-alginate NPs were prepared by the ionotropic gelation method and loaded with diltiazem hydrochloride as a model drug. These NPs were characterized in terms of particle size, zeta potential, and morphology, and results were explained in accordance with Fourier-transform infrared (FTIR) spectroscopy and differential scanning calorimetry (DSC). The incorporation of tannic acid led to more than four folds increase in drug encapsulation efficiency (i.e. from 15.3% to 69.5%) and reduced burst drug release from 44% to around 10% within the first 30 min. These findings suggest the possibility of improving the properties of Ca-alginate NPs by incorporating cross-linking aid agents under mild conditions.

Carotid Artery Stiffness, Digital Endothelial Function, and Coronary Calcium in Patients with Essential Thrombocytosis, Free of Overt Atherosclerotic Disease

PubMed Central

Vrtovec, Matjaz; Anzic, Ajda; Zupan, Irena Preloznik; Zaletel, Katja

2017-01-01

Abstract Background Patients with myeloproliferative neoplasms (MPNs) are at increased risk for atherothrombotic events. Our aim was to determine if patients with essential thrombocytosis (ET), a subtype of MPNs, free of symptomatic atherosclerosis, have greater carotid artery stiffness, worse endothelial function, greater coronary calcium and carotid plaque burden than control subjects. Patients and methods 40 ET patients without overt vascular disease, and 42 apparently healthy, age and sex-matched control subjects with comparable classical risk factors for atherosclerosis and Framingham risk of coronary disease were enrolled. All subjects were examined by physical and laboratory testing, carotid echo-tracking ultrasound, digital EndoPat pletysmography and CT coronary calcium scoring. Results No significant differences were found between ET patients and controls in carotid plaque score [1 (0-1.25) vs. 0 (0-2), p=0.30], β- index of carotid stiffness [7.75 (2.33) vs. 8.44 (2,81), p=0.23], pulse wave velocity [6,21 (1,00) vs. 6.45 (1.04) m/s; p=0.46], digital reactive hyperemia index [2.10 (0.57) vs. 2.35 (0.62), p=0.07], or augmentation index [19 (3-30) vs. 13 (5-22) %, p=0.38]. Overall coronary calcium burden did not differ between groups [Agatston score 0.1 (0-16.85) vs. 0 (0-8.55), p=0.26]. However, significantly more ET patients had an elevated coronary calcium score of >160 [6/40 vs. 0/42, p < 0.01]. Conclusions No significant differences between groups were found in carotid artery morphology and function, digital endothelial function or overall coronary calcium score. Significantly more ET patients had an elevated coronary calcium score of >160, indicating high cardiovascular risk, not predicted by the Framingham equation. PMID:28740456

Carotid Artery Stiffness, Digital Endothelial Function, and Coronary Calcium in Patients with Essential Thrombocytosis, Free of Overt Atherosclerotic Disease.

PubMed

Vrtovec, Matjaz; Anzic, Ajda; Zupan, Irena Preloznik; Zaletel, Katja; Blinc, Ales

2017-06-01

Patients with myeloproliferative neoplasms (MPNs) are at increased risk for atherothrombotic events. Our aim was to determine if patients with essential thrombocytosis (ET), a subtype of MPNs, free of symptomatic atherosclerosis, have greater carotid artery stiffness, worse endothelial function, greater coronary calcium and carotid plaque burden than control subjects. 40 ET patients without overt vascular disease, and 42 apparently healthy, age and sex-matched control subjects with comparable classical risk factors for atherosclerosis and Framingham risk of coronary disease were enrolled. All subjects were examined by physical and laboratory testing, carotid echo-tracking ultrasound, digital EndoPat pletysmography and CT coronary calcium scoring. No significant differences were found between ET patients and controls in carotid plaque score [1 (0-1.25) vs. 0 (0-2), p=0.30], β- index of carotid stiffness [7.75 (2.33) vs. 8.44 (2,81), p=0.23], pulse wave velocity [6,21 (1,00) vs. 6.45 (1.04) m/s; p=0.46], digital reactive hyperemia index [2.10 (0.57) vs. 2.35 (0.62), p=0.07], or augmentation index [19 (3-30) vs. 13 (5-22) %, p=0.38]. Overall coronary calcium burden did not differ between groups [Agatston score 0.1 (0-16.85) vs. 0 (0-8.55), p=0.26]. However, significantly more ET patients had an elevated coronary calcium score of >160 [6/40 vs. 0/42, p < 0.01]. No significant differences between groups were found in carotid artery morphology and function, digital endothelial function or overall coronary calcium score. Significantly more ET patients had an elevated coronary calcium score of >160, indicating high cardiovascular risk, not predicted by the Framingham equation.

Bone mineral accrual across growth in a mixed-ethnic group of children: are Asian children disadvantaged from an early age?

PubMed

Burrows, Melonie; Baxter-Jones, Adam; Mirwald, Robert; Macdonald, Heather; McKay, Heather

2009-05-01

We investigated the contribution of ethnicity, physical activity, body composition, and calcium intake to bone accrual across 7 years of growth. We assessed 80 Caucasian and 74 Asian boys and 81 Caucasian and 64 Asian girls at baseline and retained 155 children across all 7 years. Ethnicity, physical activity, and calcium intake were assessed by questionnaire; fat mass, lean mass, and bone mineral content (BMC) of the whole body (WB), lumbar spine (LS), total proximal femur (PF(TOT)), and femoral neck (FN) were measured using DXA (Hologic QDR 4500). We aligned children on peak height velocity and utilized multilevel modeling to assess bone mineral accrual. Height and lean mass accounted for 51.8% and 44.1% of BMC accrual in children. There was a significant difference in physical activity, calcium intake, and lean mass between Asians and Caucasian boys and girls at baseline and conclusion (p < 0.05). In boys, physical activity and ethnicity significantly predicted BMC accrual at the FN. In girls, Asians had significantly lower PF(TOT) and FN BMC. Calcium was a significant predictor of WB BMC accrual in boys and girls. In conclusion, our findings highlight the importance of accounting for ethnicity in pediatric studies. Physical activity, dietary calcium, and lean mass positively influence bone accrual and are lower in Asian compared to Caucasian children from a very young age.

Daily intake of magnesium and calcium from drinking water in relation to myocardial infarction.

PubMed

Rosenlund, Mats; Berglind, Niklas; Hallqvist, Johan; Bellander, Tom; Bluhm, Gösta

2005-07-01

A decreased risk for cardiovascular disease has been related to the hardness of drinking water, particularly high levels of magnesium. However, the evidence is still uncertain, especially in relation to individual intake from water. We used data from the Stockholm Heart Epidemiology Program, a population-based case-control study conducted during 1992-1994, to study the association between myocardial infarction and the daily intake of drinking water magnesium and calcium. Our analyses are based on 497 cases age 45-70 years, and 677 controls matched on age, sex, and hospital catchment area. Individual data on magnesium, calcium, and hardness of the domestic drinking water were assessed from waterwork registers or analyses of well water. After adjustment for the matching variables and smoking, hypertension, socioeconomic status, job strain, body mass index, diabetes, and physical inactivity, the odds ratio for myocardial infarction was 1.09 (95% confidence interval = 0.81-1.46) associated with a tap water hardness above the median (>4.4 German hardness degrees) and 0.88 (0.67-1.15) associated with a water magnesium intake above the median (>1.86 mg/d). There was no apparent sign of any exposure-response pattern related to water intake of magnesium or calcium. This study does not support previous reports of a protective effect on myocardial infarction associated with consumption of drinking water with higher levels of hardness, magnesium, or calcium.

Jeltraxin, a frog egg jelly glycoprotein, has calcium-dependent lectin properties and is related to human serum pentraxins CRP and SAP.

PubMed

Peavy, Thomas R; Hernandez, Cesar; Carroll, Edward J

2003-11-11

The egg jelly that encapsulates amphibian eggs is essential for fertilization, but its molecular composition and roles remain largely unknown. We identified a calcium-dependent lectin from the pentraxin superfamily in the egg jelly coat from the South American burrowing frog, Lepidobatrachus laevis. This lectin, jeltraxin, was related to the host-response acute phase serum proteins C-reactive P component (CRP) and serum amyloid P component (SAP). The amino acid sequence of jeltraxin is 44% identical to that of Xenopus laevis CRP, 31-35% identical to those of mammalian CRP and SAP, and 21-27% identical to those of the large fusion pentraxins. Expression of jeltraxin mRNA was restricted to the oviduct, which distinguishes it as the first serum-related pentraxin not expressed in the liver. Purified jeltraxin was previously shown to exist in an oligomeric complex of approximately 250 kDa comprised of self-associating subunits. We have demonstrated by MALDI-TOF that this configuration is due to a decameric complex of 27.7 kDa subunits. Biotinylated jeltraxin bound to the high-molecular mass components of the egg jelly in a calcium-dependent manner with specificity for beta-galactose residues. On the basis of homology modeling, we predict that jeltraxin will coordinate two calcium ions. The function of jeltraxin will likely be related to its calcium-dependent lectin properties.

Chromospherically Active Stars in the RAVE Survey

NASA Astrophysics Data System (ADS)

Žerjal, M.; Zwitter, T.; Matijevič, G.; Strassmeier, K. G.

2014-01-01

We present a qualitative characterization of activity levels of a large database of ~44,000 candidate RAVE stars (unbiased, magnitude limited medium resolution survey) that show chromospheric emission in the Ca II infrared triplet and this vastly enlarges previously known samples. Our main motivation to study these stars is the anti-correlation of chromospheric activity and stellar ages that could be calibrated using stellar clusters with known ages. Locally linear embedding used for a morphological classification of spectra revealed 53,347 cases with a suggested emission component in the calcium lines. We analyzed a subsample of ~44,000 stars with S/N>20 using a spectral subtraction technique where observed reference spectra of inactive stars were used as templates instead of synthetic ones. Both the equivalent width of the excess emission for each calcium line and their sum is derived for all candidate active stars with no respect to the origin of their emission flux. ~17,800 spectra show a detectable chromospheric flux with at least 2 σ confidence level. The overall distribution of activity levels shows a bimodal shape, with the first peak coinciding with inactive stars and the second with the pre-main-sequence cases.

Risk of calcium oxalate nephrolithiasis in postmenopausal women supplemented with calcium or combined calcium and estrogen.

PubMed

Domrongkitchaiporn, Somnuek; Ongphiphadhanakul, Boonsong; Stitchantrakul, Wasana; Chansirikarn, Sirinthorn; Puavilai, Gobchai; Rajatanavin, Rajata

2002-02-26

Recent studies showed that postmenopausal women lost less bone mass when supplemented with calcium or estrogen therapy. However, the safety of the treatments in terms of the risk of calcium oxalate stone formation is unknown. We therefore conducted this study to determine the alteration in calcium oxalate supersaturation after calcium supplement or after combined calcium and estrogen therapy in postmenopausal osteoporotic women. Fifty-six postmenopausal women were enrolled in this study. All subjects were more than 10 years postmenopausal with vertebral or femoral osteoporosis by bone mineral density criteria. They were randomly allocated to receive either 625 mg of calcium carbonate (250 mg of elemental calcium) at the end of a meal three times a day (group A, n=26) or calcium carbonate in the same manner plus 0.625 mg/day of conjugated equine estrogen and 5 mg medrogestone acetate from day 1-12 each month (group B, n=30). The age (mean +/- S.E.M.) was 66.3 +/- 1.2 and 65.1 +/- 1.1 years, weight 54.1 +/- 1.2 and 55.3 +/- 2.1 kg, in group A and group B, respectively. Urine specimens (24-h) were collected at baseline and 3 months after treatment for the determination of calcium oxalate saturation by using Tiselius's index (AP(CaOx)) and calcium/citrate ratio. After 3 months of treatment, there was no significant alteration from baseline for urinary excretion of calcium, citrate and oxalate. Urinary phosphate excretion was significantly reduced (6.3 +/- 0.7 vs. 5.1 +/- 0.7 mmol/day for group A and 8.2 +/- 0.9 vs. 5.8 +/- 0.7 mmol/day for group B, P<0.05), whereas net alkaline absorption was significantly elevated (10.1 +/- 3.6 vs. 20.1 +/- 4.4 meq/day for group A and 4.8 +/- 3.2 vs. 19.9 +/- 3.6 meq/day for group B, P<0.05). Calcium/citrate ratio and AP(CaOx) determined at baseline were not different from the corresponding values after treatment in both groups; calcium/citrate: 10.1 +/- 3.1 vs. 10.1 +/- 2.5 for group A and 9.3 +/- 1.8 vs. 11.9 +/- 2.5 for group B and AP(CaOx): 1.1 +/- 0.1 vs. 1.3 +/- 0.2 for group A and 1.2 +/- 0.2 vs. 1.1 +/- 0.1 for group B. There were eight and nine patients with high AP(CaOx), or >2, at baseline and after treatment, respectively. Calcium supplement with a meal or combined calcium supplement and estrogen therapy is not associated with a significant increased risk of calcium oxalate stone formation in the majority of postmenopausal osteoporotic patients. Determination of urinary saturation for calcium oxalate after calcium and estrogen supplements, especially at the initial phase of treatment, may be helpful in the avoidance of nephrolithiasis.

[Calcium supplementation uncovering lactose intolerance - a case report].

PubMed

Trifina, Eva; Geissler, Dietmar; Zwettler, Elisabeth; Klaushofer, Klaus; Mikosch, Peter

2012-03-01

A 44 yr-old female with osteoporosis had no relevant gastrointestinal symptoms and did not avoid any specific food. However, after prescription of a lactose-rich calcium supplementation, clinical symptoms suspicious for lactose intolerance occurred, which were thereafter confirmed by a lactose tolerance test. Lactose intolerance may present with only slight or subtle symptoms. Drugs containing lactose may induce or increase gastrointestinal symptoms in patients with lactose intolerance. In case of gastrointestinal symptoms occurring after the initiation of drugs containing lactose, the possibility of lactose intolerance should be considered and tested by lactose tolerance test or genetic testing for the LCT (-13910) polymorphism. Due to the prevalence of about 15-25% lactose intolerance in the Austrian population, lactose free drugs should be prescribed as widely as possible.

Low Density Lipoproteins Promote Unstable Calcium Handling Accompanied by Reduced SERCA2 and Connexin-40 Expression in Cardiomyocytes

PubMed Central

Cabello, Nuria; Llach, Anna; Vallmitjana, Alexander; Benítez, Raúl; Badimon, Lina; Cinca, Juan; Llorente-Cortés, Vicenta; Hove-Madsen, Leif

2013-01-01

The damaging effects of high plasma levels of cholesterol in the cardiovascular system are widely known, but little attention has been paid to direct effects on cardiomyocyte function. We therefore aimed at testing the hypothesis that Low Density Lipoprotein (LDL) cholesterol affects calcium dynamics and signal propagation in cultured atrial myocytes. For this purpose, mRNA and protein expression levels were determined by real time PCR and western blot analysis, respectively, and intracellular calcium was visualized in fluo-4 loaded atrial HL-1 myocyte cultures subjected to field stimulation. At low stimulation frequencies all cultures had uniform calcium transients at all tested LDL concentrations. However, 500 µg LDL/mL maximally reduced the calcium transient amplitude by 43% from 0.30±0.04 to 0.17±0.02 (p<0.05). Moreover, LDL-cholesterol dose-dependently increased the fraction of alternating and irregular beat-to-beat responses observed when the stimulation interval was shortened. This effect was linked to a concurrent reduction in SERCA2, RyR2, IP3RI and IP3RII mRNA levels. SERCA2 protein levels were also reduced by 43% at 200 µg LDL/mL (p<0.05) and SR calcium loading was reduced by 38±6% (p<0.001). By contrast, HDL-cholesterol had no significant effect on SERCA expression or SR calcium loading. LDL-cholesterol also slowed the conduction velocity of the calcium signal from 3.2+0.2 mm/s without LDL to 1.7±0.1 mm/s with 500 µg LDL/mL (p<0.05). This coincided with a reduction in Cx40 expression (by 44±3%; p<0.05 for mRNA and by 79±2%; p<0.05 for Cx40 protein at 200 µg/ml LDL) whereas the Cx-43 expression did not significantly change. In conclusion, LDL-cholesterol destabilizes calcium handling in cultured atrial myocytes subjected to rapid pacing by reducing SERCA2 and Cx40 expression and by slowing the conduction velocity of the calcium signal. PMID:23516438

Lack of association of oral calcium supplementation with coronary artery calcification in rheumatoid arthritis.

PubMed

Geraldino-Pardilla, Laura; Dhaduvai, Shanthi; Giles, Jon T; Bathon, Joan M

2015-06-01

To investigate the association between oral calcium supplementation and coronary artery calcification among rheumatoid arthritis (RA) patients without known cardiovascular disease (CVD). This study was conducted as a nested, prospective cohort study of RA patients without known CVD. The daily supplemental calcium dose was ascertained from each patients' list of prescription and over-the-counter medications at baseline and at visit 2 (median 20 months postbaseline). The coronary artery calcium (CAC) score, a measure of coronary atherosclerosis, was assessed by cardiac multidetector row computed tomography at baseline and at visit 3 (median 39 months postbaseline). The association between calcium supplementation and CAC was explored. Among the 145 RA patients studied, 42 (28%) were taking ≥1,000 mg/day of supplemental calcium at baseline. A CAC score of >100 units was seen in 44 patients (30%) at baseline and 50 patients (34%) at followup. Baseline CAC scores of >100 units were significantly less frequent in patients receiving the higher dosage (≥1,000 mg/day) of supplemental calcium than in those receiving the lower dosage (<1,000 mg/day) (odds ratio [OR] 0.28, 95% confidence interval [95% CI] 0.11-0.74); this association remained significant after adjustment for relevant confounders (adjusted OR 0.30, 95% CI 0.09-0.93). Similarly, at the third study visit, CAC scores of >100 units were less frequent in the higher supplemental calcium dose group compared to the lower dose group (OR 0.41, 95% CI 0.18-0.95); however, after adjustment for relevant confounders, the statistical significance of this association was lost (adjusted OR 0.39, 95% CI 0.14-1.12). No effect of sex heterogeneity was seen in the association of calcium supplementation with coronary artery calcification, and no change in the CAC score over time was observed. Higher levels of oral calcium supplementation were not associated with an increased risk of coronary atherosclerosis, as measured by the CAC score, in this RA cohort. © 2015, American College of Rheumatology.

Association Between Serum Calcium Level and Extent of Bleeding in Patients With Intracerebral Hemorrhage.

PubMed

Morotti, Andrea; Charidimou, Andreas; Phuah, Chia-Ling; Jessel, Michael J; Schwab, Kristin; Ayres, Alison M; Romero, Javier M; Viswanathan, Anand; Gurol, M Edip; Greenberg, Steven M; Anderson, Christopher D; Rosand, Jonathan; Goldstein, Joshua N

2016-11-01

Calcium is a key cofactor of the coagulation cascade and may play a role in the pathophysiology of intracerebral hemorrhage (ICH). To investigate whether a low serum calcium level is associated with an increase in the extent of bleeding in patients with ICH as measured by baseline hematoma volume and risk of hematoma expansion. Prospective cohort study of 2103 consecutive patients with primary ICH ascertained during the period between 1994 and 2015 at an academic medical center. The statistical analysis was performed in January 2016. Total calcium level was measured on admission, and hypocalcemia was defined as a serum calcium level of less than 8.4 mg/dL. Baseline and follow-up hematoma volumes, detected by noncontrast computed tomography, were measured using a computer-assisted semiautomatic analysis. Hematoma expansion was defined as an increase of more than 30% or 6 mL from baseline ICH volume. Associations between serum calcium level and baseline hematoma volume and between serum calcium level and ICH expansion were investigated in multivariable linear and logistic regression models, respectively. A total of 2123 patients with primary ICH were screened, and 2103 patients met the inclusion criteria (mean [SD] age, 72.7 [12.5] years; 54.3% male patients), of whom 229 (10.9%) had hypocalcemia on admission. Hypocalcemic patients had a higher median baseline hematoma volume than did normocalcemic patients (37 mL [IQR, 15-72 mL] vs 16 mL [IQR, 6-44 mL]; P < .001). Low calcium levels were independently associated with higher baseline ICH volume (β = -0.13, SE = .03, P < .001). A total of 1393 patients underwent follow-up noncontrast computed tomography and were included in the ICH expansion analysis. In this subgroup, a higher serum calcium level was associated with reduced risk of ICH expansion (odds ratio, 0.55 [95% CI, 0.35-0.86]; P = .01), after adjusting for other confounders. Hypocalcemia correlates with the extent of bleeding in patients with ICH. A low calcium level may be associated with a subtle coagulopathy predisposing to increased bleeding and might therefore be a promising therapeutic target for acute ICH treatment trials.

Reported Dietary Intake, Disparity between the Reported Consumption and the Level Needed for Adequacy and Food Sources of Calcium, Phosphorus, Magnesium and Vitamin D in the Spanish Population: Findings from the ANIBES Study.

PubMed

Olza, Josune; Aranceta-Bartrina, Javier; González-Gross, Marcela; Ortega, Rosa M; Serra-Majem, Lluis; Varela-Moreiras, Gregorio; Gil, Ángel

2017-02-21

Calcium, phosphorus, magnesium and vitamin D have important biological roles in the body, especially in bone metabolism. We aimed to study the reported intake, the disparity between the reported consumption and the level needed for adequacy and food sources of these four nutrients in the Spanish population. We assessed the reported intake for both, general population and plausible reporters. Results were extracted from the ANIBES survey, n = 2009. Three-day dietary reported intake data were obtained and misreporting was assessed according to the European Food Safety Authority (EFSA). Mean ± SEM (range) total reported consumption of calcium, phosphorus, magnesium, and vitamin D for the whole population were 698 ± 7 mg/day (71-2551 mg/day), 1176 ± 8 mg/day, (331-4429 mg/day), 222 ± 2 mg/day (73-782 mg/day), and 4.4 ± 0.1 µg/day (0.0-74.2 µg/day), respectively. In the whole group, 76% and 66%; 79% and 72%; and 94% and 93% of the population had reported intakes below 80% of the national and European recommended daily intakes for calcium, magnesium and vitamin D, respectively; these percentages were over 40% when the plausible reporters were analysed separately. The main food sources were milk and dairy products for calcium and phosphorus, cereals and grains for magnesium and fish for vitamin D. In conclusion, there is an important percentage of the Spanish ANIBES population not meeting the recommended intakes for calcium, magnesium and vitamin D.

A Randomized Trial of Vitamin D3 Supplementation in Children: Dose-Response Effects on Vitamin D Metabolites and Calcium Absorption

PubMed Central

Laing, E. M.; Hill Gallant, K. M.; Hall, D. B.; McCabe, G. P.; Hausman, D. B.; Martin, B. R.; Warden, S. J.; Peacock, M.; Weaver, C. M.

2013-01-01

Context: Changes in serum vitamin D metabolites and calcium absorption with varying doses of oral vitamin D3 in healthy children are unknown. Objective: Our objective was to examine the dose-response effects of supplemental vitamin D3 on serum vitamin D metabolites and calcium absorption in children living at two U.S. latitudes. Design: Black and white children (n = 323) participated in a multisite (U.S. latitudes 34° N and 40° N), triple-masked trial. Children were randomized to receive oral vitamin D3 (0, 400, 1000, 2000, and 4000 IU/d) and were sampled over 12 weeks in winter. Serum 25-hydroxyvitamin D (25(OH)D) and 1,25-dihydroxyvitamin D (1,25(OH)2D) were measured using RIA and intact PTH (iPTH) by immunoradiometric assay. Fractional calcium absorption was determined from an oral stable isotope 44Ca (5 mg) in a 150-mg calcium meal. Nonlinear and linear regression models were fit for vitamin D metabolites, iPTH, and calcium absorption. Results: The mean baseline 25(OH)D value for the entire sample was 70.0 nmol/L. Increases in 25(OH)D depended on dose with 12-week changes ranging from −10 nmol/L for placebo to 76 nmol/L for 4000 IU. Larger 25(OH)D gains were observed for whites vs blacks at the highest dose (P < .01). Gains for 1,25(OH)2D were not significant (P = .07), and decreases in iPTH were not dose-dependent. There was no dose effect of vitamin D on fractional calcium absorption when adjusted for pill compliance, race, sex, or baseline 25(OH)D. Conclusion: Large increases in serum 25(OH)D with vitamin D3 supplementation did not increase calcium absorption in healthy children living at 2 different latitudes. Supplementation with 400 IU/d was sufficient to maintain wintertime 25(OH)D concentrations in healthy black, but not white, children. PMID:24092833

Magnesium retention from metabolic-balance studies in female adolescents: impact of race, dietary salt, and calcium123

PubMed Central

Palacios, Cristina; Wigertz, Karin; Braun, Michelle; Martin, Berdine R; McCabe, George P; McCabe, Linda; Pratt, J Howard; Peacock, Munro; Weaver, Connie M

2013-01-01

Background: Previously, we showed that black girls retained more calcium than white girls did and that salt loading negatively affected calcium retention. Racial differences likely exist in other bone minerals also, such as magnesium, in response to salt loading during growth. Objective: We studied racial differences in magnesium metabolism in response to dietary sodium and calcium during rapid bone growth. Design: Twenty-seven white and 40 black girls (11–15 y old) were studied for 3 wk while they consumed low-sodium (1.3 g/d) and high-sodium (3.8 g/d) diets by using a randomized-order, crossover metabolic study with 3 dietary calcium intakes; the magnesium dietary intake was fixed at 230 mg/d. Urine and feces were collected during each 3-wk period in 24-h pools and analyzed for magnesium. A mixed-model ANOVA was used to determine the effect of race and dietary sodium with calcium intake as a covariate. Results: Salt loading or calcium intake had no significant effect on urinary magnesium excretion. Blacks excreted significantly less urinary magnesium (mean ± SD: 83.8 ± 25.6 mg/d) than did whites (94.9 ± 27.3 mg/d; P < 0.05). No effects were observed in fecal magnesium excretion. Magnesium retention was higher with the low-sodium diet (50.1 ± 44.0 mg/d) than with the high-sodium diet (39.3 ± 49.8 mg/d) (P < 0.05), with no effects of race or calcium intake. Salt loading had no effect on biomarkers. Whites had higher 25-hydroxyvitamin D and insulin-like growth factor binding protein 3 but lower 1,25-dihydroxyvitamin D and parathyroid hormone concentrations. Conclusions: Blacks excreted less urinary magnesium than did whites. Magnesium retention was similar between races but higher with the low-sodium diet. Kinetic studies are needed to fully explain magnesium homeostasis. This trial was registered at clinicaltrials.gov as NCT01564238. PMID:23553157

Improvement of mineral and bone metabolism markers is associated with better survival in haemodialysis patients: the COSMOS study.

PubMed

Fernández-Martín, José Luis; Martínez-Camblor, Pablo; Dionisi, María Paula; Floege, Jürgen; Ketteler, Markus; London, Gérard; Locatelli, Francesco; Gorriz, José Luis; Rutkowski, Boleslaw; Ferreira, Aníbal; Bos, Willem-Jan; Covic, Adrian; Rodríguez-García, Minerva; Sánchez, José Emilio; Rodríguez-Puyol, Diego; Cannata-Andia, Jorge B

2015-09-01

Abnormalities in serum phosphorus, calcium and parathyroid hormone (PTH) have been associated with poor survival in haemodialysis patients. This COSMOS (Current management Of Secondary hyperparathyroidism: a Multicentre Observational Study) analysis assesses the association of high and low serum phosphorus, calcium and PTH with a relative risk of mortality. Furthermore, the impact of changes in these parameters on the relative risk of mortality throughout the 3-year follow-up has been investigated. COSMOS is a 3-year, multicentre, open-cohort, prospective study carried out in 6797 adult chronic haemodialysis patients randomly selected from 20 European countries. Using Cox proportional hazard regression models and penalized splines analysis, it was found that both high and low serum phosphorus, calcium and PTH were associated with a higher risk of mortality. The serum values associated with the minimum relative risk of mortality were 4.4 mg/dL for serum phosphorus, 8.8 mg/dL for serum calcium and 398 pg/mL for serum PTH. The lowest mortality risk ranges obtained using as base the previous values were 3.6-5.2 mg/dL for serum phosphorus, 7.9-9.5 mg/dL for serum calcium and 168-674 pg/mL for serum PTH. Decreases in serum phosphorus and calcium and increases in serum PTH in patients with baseline values of >5.2 mg/dL (phosphorus), >9.5 mg/dL (calcium) and <168 pg/mL (PTH), respectively, were associated with improved survival. COSMOS provides evidence of the association of serum phosphorus, calcium and PTH and mortality, and suggests survival benefits of controlling chronic kidney disease-mineral and bone disorder biochemical parameters in CKD5D patients. © The Author 2015. Published by Oxford University Press on behalf of ERA-EDTA. All rights reserved.

New chemolysis for urological calcium phosphate calculi – a study in vitro

PubMed Central

Xiang-bo, Zhang; Zhi-ping, Wang; Jian-min, Duan; Jian-zhong, Lu; Bao-liang, Ma

2005-01-01

Background Advances in techniques have left very few indications for open surgical extraction of urinary stones currently. These advances notwithstanding, the search continues for medical approaches to urinary stone management. In this study, we perform an in vitro study analyzing the efficiency and prospect of two new complex solutions in urological calcium phosphate calculi dissolution. Methods Eighteen stones composed mainly of calcium phosphates were taken from patients who underwent kidney stone surgery. These stones were large enough (weight range 0.514–0.928 g) to be fragmented and matched equally into six groups. Chemolysis of phosphate stones was done with six different solvents and was repeated 3 times with 6 stones for each solution. At 24, 48 and 72 h, reduction in weight, percentage weight change, and dissolution rate; the dissolution rates at pH 5.0, 7.0 and 8.5 for each solution, using different cations (Na+, K+ or Ca2+), according to different dilutions (1:1, 1:2, 1:3, 1:4) of S1 and S2 were simultaneously determined. Results Calcium phosphate calculi were poorly dissolved by Phys and Art, and they had a low dissolution rate in pH 8.5 EDTA. The most effective solutions were S1, S2 and R, with 72 h mean dissolution rates: 5.75 ± 0.44 mg/hr (S1), 5.2 ± 0.63 mg/hr (S2), 4.55 ± 0.46 mg/hr (R) ( ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA; p < 0.05, S1 vs R, LSD-test). The mean percentage weight loss at 72 h was: 52.1 ± 15.75 % (S1), 44.4 ± 7.37 % (S2) and 40.5 ± 3.67 % (R) ( ± s, p < 0.01 R, S1 and S2 vs Phys, Art and EDTA, LSD-test). Diluted twice, S1 and S2 had even better effectiveness than their initial solution. The additive of Na+, K+ or Ca2+ greatly reduced the dissolution rates of S1, S2. Conclusion Our data indicate that test solutions S1 and S2 are effective solvents in the chemolysis of calcium phosphate stones. At twice dilutions, these solutions are even more useful in the treatment of stone disease. PMID:15907215

Connection between integrins and cell activation in rat adrenal glomerulosa cells: a role for Arg-Gly-Asp peptide in the activation of the p42/p44(mapk) pathway and intracellular calcium.

PubMed

Campbell, Shirley; Otis, Melissa; Côté, Mylène; Gallo-Payet, Nicole; Payet, Marcel Daniel

2003-04-01

Integrins are responsible for adhesion and activation of several intracellular cascades. The present study was aimed at determining whether the interaction between fibronectin and integrins could generate pathways involved in physiological functions of rat adrenal glomerulosa cells. Immunofluorescence studies and adhesion assays showed that fibronectin was the best matrix in promoting the formation of focal adhesion. Binding of glomerulosa cells to fibronectin, but not to collagen I or poly-L-lysine, involved the integrin-binding sequence Arg-Gly-Asp (RGD). Activation of glomerulosa cells with Arg-Gly-Asp-Ser (RGDS) induced an increase in [Ca(2+)](i), whereas fibronectin triggered a release of Ca(2+) from InsP(3)-sensitive Ca(2+) stores. Aldosterone secretion induced by ACTH, angiotensin II, and RGDS and proliferation were improved on fibronectin, compared with poly-L-lysine. The RGDS peptide induced a transient increase in the activity of the p42/p44(mapk), independent of phosphatidylinositol-3 kinase and protein kinase C. Integrins alpha(5) and alpha(V) as well as their fibronectin receptor partners beta(1) and beta(3), were identified. These results suggest that in rat adrenal glomerulosa cells, binding of the alpha(5)beta(1), alpha(v)beta(1), or alpha(v)beta(3) integrins to fibronectin is involved in the generation of two important signaling events, increase in intracellular calcium, and activation of the p42/p44(mapk) cascade, leading to cell proliferation and aldosterone secretion.

Mechanism for electrosilent Ca2+ transport to cause calcification of spicules in sea urchin embryos.

PubMed

Yasumasu, I; Mitsunaga, K; Fujino, Y

1985-07-01

Embryos of the sea urchin, Hemicentrotus pulcherrimus, kept in sea water containing the calcium antagonists, diltiazem and verapamil, or an anion transport inhibitor, 4,4'-diisothiocyano-2,2'-disulfonic acid stilbene (DIDS), during a developmental period between the mesenchyme blastula and the pluteus corresponding stage, became abnormal plutei with poorly developed arms and quite small spicules. Treatment with ethacrynic acid and furosemide, inhibitors of chloride transport, during the same period of development yielded quasi-normal plutei with poor spicules and somewhat developed arms. In late gastrulae, the inhibitory effects of these calcium antagonists and DIDS on the uptake of 45Ca2+ in whole embryos were as strong as those on 45Ca deposition in spicules, whereas the effects of chloride transport inhibitors on calcium deposition in the spicules were markedly stronger than on its uptake in whole embryos. Electrosilent uptake of Ca2+ seems to be established mainly by coupled influx of chloride in the cells which mediate spicule calcification, and by concomitant influx of anions in the other cells. In swimming blastulae, 45Ca2+ uptake was inhibited by calcium antagonists and DIDS, but not by chloride transport inhibitors. Ca2+ uptake probably becomes coupled with chloride influx only in embryos in which spicule calcification occurs.

Metabolic diagnosis and medical prevention of calcium nephrolithiasis and its systemic manifestations: a consensus statement.

PubMed

Gambaro, Giovanni; Croppi, Emanuele; Coe, Fredric; Lingeman, James; Moe, Orson; Worcester, Elen; Buchholz, Noor; Bushinsky, David; Curhan, Gary C; Ferraro, Pietro Manuel; Fuster, Daniel; Goldfarb, David S; Heilberg, Ita Pfeferman; Hess, Bernard; Lieske, John; Marangella, Martino; Milliner, Dawn; Preminger, Glen M; Reis Santos, Jose' Manuel; Sakhaee, Khashayar; Sarica, Kemal; Siener, Roswitha; Strazzullo, Pasquale; Williams, James C

2016-12-01

Recently published guidelines on the medical management of renal stone disease did not address relevant topics in the field of idiopathic calcium nephrolithiasis, which are important also for clinical research. A steering committee identified 27 questions, which were proposed to a faculty of 44 experts in nephrolithiasis and allied fields. A systematic review of the literature was conducted and 5216 potentially relevant articles were selected; from these, 407 articles were deemed to provide useful scientific information. The Faculty, divided into working groups, analysed the relevant literature. Preliminary statements developed by each group were exhaustively discussed in plenary sessions and approved. Statements were developed to inform clinicians on the identification of secondary forms of calcium nephrolithiasis and systemic complications; on the definition of idiopathic calcium nephrolithiasis; on the use of urinary tests of crystallization and of surgical observations during stone treatment in the management of these patients; on the identification of patients warranting preventive measures; on the role of fluid and nutritional measures and of drugs to prevent recurrent episodes of stones; and finally, on the cooperation between the urologist and nephrologist in the renal stone patients. This document has addressed idiopathic calcium nephrolithiasis from the perspective of a disease that can associate with systemic disorders, emphasizing the interplay needed between urologists and nephrologists. It is complementary to the American Urological Association and European Association of Urology guidelines. Future areas for research are identified.

The potential role of salt abuse on the risk for kidney stone formation

NASA Technical Reports Server (NTRS)

Sakhaee, K.; Harvey, J. A.; Padalino, P. K.; Whitson, P.; Pak, C. Y.

1993-01-01

The kidney stone-forming risk of a high sodium diet was evaluated by assessing the effect of such a diet on the crystallization of stone-forming salts in urine. Fourteen normal subjects participated in 2 phases of study of 10 days duration each, comprising a low sodium phase (basal metabolic diet containing 50 mmol. sodium per day) and a high sodium phase (basal diet plus 250 mmol. sodium chloride per day). The high sodium intake significantly increased urinary sodium (34 +/- 12 to 267 +/- 56 mmol. per day), calcium (2.73 +/- 1.03 to 3.93 +/- 1.51 mmol. per day) and pH (5.79 +/- 0.44 to 6.15 +/- 0.25), and significantly decreased urinary citrate (3.14 +/- 1.19 to 2.52 +/- 0.83 mmol. per day). Arterialized venous blood bicarbonate and total serum carbon dioxide concentrations decreased significantly during the high sodium diet, whereas serum chloride concentration increased. However, no change in arterialized venous pH was detected. Thus, a high sodium intake not only increased calcium excretion, but also increased urinary pH and decreased citrate excretion. The latter effects are probably due to sodium-induced bicarbonaturia and a significant decrease in serum bicarbonate concentration, respectively. Commensurate with these changes, the urinary saturation of calcium phosphate (brushite) and monosodium urate increased, and the inhibitor activity against calcium oxalate crystallization (formation product) decreased. The net effect of a high sodium diet was an increased propensity for the crystallization of calcium salts in urine.

Health risks and benefits from calcium and vitamin D supplementation: Women's Health Initiative clinical trial and cohort study.

PubMed

Prentice, R L; Pettinger, M B; Jackson, R D; Wactawski-Wende, J; Lacroix, A Z; Anderson, G L; Chlebowski, R T; Manson, J E; Van Horn, L; Vitolins, M Z; Datta, M; LeBlanc, E S; Cauley, J A; Rossouw, J E

2013-02-01

The Women's Health Initiative (WHI) double-blind, placebo-controlled clinical trial randomly assigned 36,282 postmenopausal women in the U.S. to 1,000 mg elemental calcium carbonate plus 400 IU of vitamin D(3) daily or placebo, with average intervention period of 7.0 years. The trial was designed to test whether calcium plus vitamin D supplementation in a population in which the use of these supplements was widespread would reduce hip fracture, and secondarily, total fracture and colorectal cancer. This study further examines the health benefits and risks of calcium and vitamin D supplementation using WHI data, with emphasis on fractures, cardiovascular disease, cancer, and total mortality. WHI calcium and vitamin D randomized clinical trial (CT) data through the end of the intervention period were further analyzed with emphasis on treatment effects in relation to duration of supplementation, and these data were contrasted and combined with corresponding data from the WHI prospective observational study (OS). Among women not taking personal calcium or vitamin D supplements at baseline, the hazard ratio [HR] for hip fracture occurrence in the CT following 5 or more years of calcium and vitamin D supplementation versus placebo was 0.62 (95 % confidence interval (CI), 0.38-1.00). In combined analyses of CT and OS data, the corresponding HR was 0.65 (95 % CI, 0.44-0.98). Supplementation effects were not apparent on the risks of myocardial infarction, coronary heart disease, total heart disease, stroke, overall cardiovascular disease, colorectal cancer, or total mortality, while evidence for a reduction in breast cancer risk and total invasive cancer risk among calcium plus vitamin D users was only suggestive. Though based primarily on a subset analysis, long-term use of calcium and vitamin D appears to confer a reduction that may be substantial in the risk of hip fracture among postmenopausal women. Other health benefits and risks of supplementation at doses considered, including an elevation in urinary tract stone formation, appear to be modest and approximately balanced.

[Gallbladder Stone Types in Patients with Cholelithiasis and Clonorchis sinensis Infection in the Endemic Area of Clonorchiasis].

PubMed

Ma, Rui-hong; Qiao, Tie; Luo, Zhen-liang; Luo, Xiao-bing; Zheng, Pei-ming; Yang, Liu-qing

2015-06-01

To investigate the relationship between Clonorchis sinensis infection and the gallbladder stone type in patients with cholelithiasis in the endemic area of clonorchiasis. Gallbladder stones were collected from 598 patients with cholelithiasis through minimally invasive gallbladder-preserving cholelithotomy in the Sixth People's Hospital of Nansha District from May 2009 to October 2012. The stone samples were analyzed for composition by Fourier transform infrared spectroscopy to identify their types. The Clonorchis sinensis eggs were detected in the stones by microscopic examination, and the detection rates of eggs were calculated for different stone types. Then the clinical characteristics and biochemical indicators were compared among patients with different types of stones, as well as between Clonorchis sinensis egg-positive and -negative patients with the calcium-carbonate type of stones. Some calcium-carbonate stones positive for Clonorchis sinensis eggs were randomly selected for further scanning electron microscopy (SEM) examination. Of the stones from 598 patients, 234 (39.1%) were cholesterol type, 133 (22.2%) bile pigment type, 112(18.7%) calcium-carbonate type, 86 (14.4%) mixed types and 33(5.5%) were others. The detection rate of Clonorchis sinensis eggs in these types was 6% (15/234), 44% (59/133), 60% (67/112), 36% (31/ 86) and 30% (10/33), respectively, being highest in calcium-carbonate stones while lowest in cholesterol stones. The Co2-combining power of the plasma was higher in patients with calcium-carbonate and mixed stones than in those with cholesterol stones (P < 0.05), and the CO2-combining power of the bile and biliary pH were both higher in patients with calcium-carbonate types than in those with other types (P < 0.05). In addition, in patients with calcium-carbonate stones, the CO2-combining powers of the plasma and the bile, as well as biliary pH were all higher in the egg-positives than in the egg-negatives. Further, both light microscopy and SEM revealed adherence of the Clonorchis sinensis eggs to calcium-carbonate crystals. The infection rate of Clonorchis sinensis is higher in patients with calcium-carbonate gallbladder stones than in those with other types of stones.

Mg/Ca, Sr/Ca and Ca isotope ratios in benthonic foraminifers related to test structure, mineralogy and environmental controls

NASA Astrophysics Data System (ADS)

Gussone, Nikolaus; Filipsson, Helena L.; Kuhnert, Henning

2016-01-01

We analysed Mg/Ca, Sr/Ca and Ca isotope ratios of benthonic foraminifers from sediment core tops retrieved during several research cruises in the Atlantic Ocean, in order to improve the understanding of isotope fractionation and element partitioning resulting from biomineralisation processes and changes in ambient conditions. Species include foraminifers secreting tests composed of hyaline low magnesium calcite, porcelaneous high magnesium calcite as well as aragonite. Our results demonstrate systematic isotope fractionation and element partitioning patterns specific for these foraminiferal groups. Calcium isotope fractionation is similar in porcelaneous and hyaline calcite tests and both groups demonstrate the previously described anomaly with enrichment of heavy isotopes around 3-4 °C (Gussone and Filipsson, 2010). Calcium isotope ratios of the aragonitic species Hoeglundina elegans, on the other hand, are about 0.4‰ lighter compared to the calcitic species, which is in general agreement with stronger fractionation in inorganic aragonite compared to calcite. However, the low and strongly variable Sr content suggests additional processes during test formation, and we propose that transmembrane ion transport or a precursor phase to aragonite may be involved. Porcelaneous tests, composed of high Mg calcite, incorporate higher amounts of Sr compared to hyaline low Mg calcite, in agreement with inorganic calcite systematics, but also porcelaneous tests with reduced Mg/Ca show high Sr/Ca. While calcium isotopes, Sr/Ca and Mg/Ca in benthonic foraminifers primarily appear to fractionate and partition with a dominant inorganic control, δ44/40Ca temperature and growth rate dependencies of benthonic foraminifer tests favour a dominant contribution of light Ca by transmembrane transport relative to unfractionated seawater Ca to the calcifying fluid, thus controlling the formation of foraminiferal δ44/40Ca and Sr/Ca proxy signals.

Calcium Sensitivity, Force Frequency Relationship and Cardiac Troponin I: Critical Role of PKA and PKC Phosphorylation Sites

PubMed Central

Ramirez-Correa, Genaro A.; Cortassa, Sonia; Stanley, Brian; Gao, Wei Dong; Murphy, Anne M.

2010-01-01

Transgenic models with pseudo phosphorylation mutants of troponin I, PKA sites at Ser 22 and 23 (cTnIDD22,23 mice) or PKC sites at Ser 42 and 44 (cTnIAD22,23DD42,44) displayed differential force-frequency relationships and afterload relaxation delay in vivo. We hypothesized that cTnI PKA and PKC phospho-mimics impact cardiac muscle rate-related developed twitch force and relaxation kinetics in opposite directions. cTnIDD22,23 transgenic mice produces a force frequency relationship (FFR) equivalent to control NTG albeit at lower peak [Ca2+]i, while cTnIAD22,23DD42,44 TG mice had a flat FFR with normal peak systolic [Ca2+]i, thus suggestive of diminished responsiveness to [Ca2+]i at higher frequencies. Force-[Ca2+]i hysteresis analysis revealed that cTnIDD22,23 mice have a combined enhanced myofilament calcium peak response with an enhanced slope of force development and decline per unit of [Ca2+]i, whereas cTnIAD22,23DD42,44 transgenic mice showed the opposite. The computational ECME model predicts that the TG lines may be distinct from each other due to different rate constants for association/dissociation of Ca2+ at the regulatory site of cTnC. Our data indicate that cTnI phosphorylation at PKA sites plays a critical role in the FFR by increasing relative myofilament responsiveness, and results in a distinctive transition between activation and relaxation, as displayed by Force-[Ca2+]i hysteresis loops. These findings may have important implications for understanding the specific contribution of cTnI to β-adrenergic inotropy and lusitropy and to adverse contractile effects of PKC activation, which is relevant during heart failure development. PMID:20083117

Treating mineral metabolism disorders in patients undergoing long hemodialysis: a search for an optimal strategy.

PubMed

Jean, Guillaume; Vanel, Thierry; Terrat, Jean-Claude; Hurot, Jean-Marc; Lorriaux, Christie; Mayor, Brice; Chazot, Charles

2009-10-01

In hemodialysis (HD) patients, mineral metabolism (MM) disorders have been associated with an increased mortality rate. We report the evolution of MM parameters in a stable HD population undergoing long hemodialysis by performing an annual cross-sectional analysis for every year from 1994 to 2008. The therapeutic strategy has changed: the dialysate calcium concentration has decreased from a mean of 1.7 +/- 0.1 to 1.5 +/- 0.07 mmol/L and has been adapted to parathyroid hormone serum levels (from 1 to 1.75 mmol/L). The use of calcium-based and aluminum-based phosphate binders has decreased and they have been replaced by sevelamer; alfacalcidol has partly been replaced by native vitamin D. The percentage of patients with a parathyroid hormone serum level between 150 and 300 pg/mL has increased from 9% to 67% (P<0.001); the percentage of patients with phosphataemia between 1.15 and 1.78 mmol/L has increased from 39% to 84% (P<0.001). The percentage of those with albumin-corrected calcemia between 2.1 and 2.37 mmol/L has increased from 29% to 61% (P<0.001), and that of patients with a calcium-phosphorous product (Ca x P) level >4.4 mmol/L decreased from 8.8% to 2% (P=0.02). Although patients undergo long and intensive HD treatment, MM disorders are common. However, an appropriate strategy, mostly consisting of native vitamin D supplementation, progressive replacement of calcium-based phosphate binders with non-calcium-based ones, and individualization of dialysis session duration and dialysate calcium concentration, would result in a drastic improvement.

Studying the Role for CD4+ T Cell Subsets in Human Lupus

DTIC Science & Technology

2013-07-01

heterogeneous, ranging from self- originating uric acid , calcium pyrophosphate crystals, choles- terol crystals, ATP, and glucose to environment-derived...Tardivel, and J. Tschopp. 2006. Gout- associated uric acid crystals activate the NALP3 inflammasome. Nature 440: 237–241. 44. Napirei, M., H. Karsunky, B...patterns (PAMPs) commonly found in microorganisms (1, 2). Different classes of PRRs have been identified. These receptors include TLRs, retinoic acid

Early Solar System Alkali Fractionation Events Recorded by K-Ca Isotopes in the Yamato-74442 LL-Chondritic Breccia

NASA Technical Reports Server (NTRS)

Tatsunori, T.; Misawa, K.; Okano, O.; Shih, C.-Y.; Nyquist, L. E.; Simon, J. I.; Tappa, M. J.; Yoneda, S.

2015-01-01

Radiogenic ingrowth of Ca-40 due to decay of K-40 occurred early in the solar system history causing the Ca-40 abundance to vary within different early-former reservoirs. Marshall and DePaolo ] demonstrated that the K-40/Ca-40 decay system could be a useful radiogenic tracer for studies of terrestrial rocks. Shih et al. [3,4] determined 40K/40Ca ages of lunar granitic rock fragments and discussed the chemical characteristics of their source materials. Recently, Yokoyama et al. [5] showed the application of the K-40/Ca-40 chronometer for high K/Ca materials in ordinary chondrites (OCs). High-precision calcium isotopic data are needed to constrain mixing processes among early solar system materials and the time of planetesimal formation. To better constrain the solar system calcium isotopic compositions among astromaterials, we have determined the calcium isotopic compositions of OCs and an angrite. We further estimated a source K/Ca ratio for alkali-rich fragments in a chondritic breccia using the estimated solar system initial Ca-40/Ca-44.

Modification of Ca isotope and trace metal composition of the major matrices involved in shell formation of Mytilus edulis

NASA Astrophysics Data System (ADS)

Heinemann, Agnes; Fietzke, Jan; Eisenhauer, Anton; Zumholz, Karsten

2008-01-01

In this study we present the first combined investigation into the composition of the major matrices involved in calcification processes (surrounding water, extrapallial fluid, aragonite, and calcite) of Mytilus edulis with respect to their calcium isotope (δ44/40Ca) and elemental compositions (Sr/Ca and Mg/Ca). Our aim was to examine the suitability of Mytilus edulis as a proxy archive and to contribute to the understanding of the process of biomineralization. Mytilus edulis specimens were live collected from the Schwentine Estuary, Kiel Fjord, and North Sea (Sylt). δ44/40Ca was determined by thermal ionization mass spectrometry (TIMS) accompanied by measurements of Mg/Ca and Sr/Ca using inductively coupled plasma-optical emission spectroscopy (ICP-OES). The elemental and isotopic compositions of the investigated matrices showed systematic offsets. The carbonates are strongly depleted in their magnesium and strontium concentrations and fractionated toward lighter calcium isotope compositions relative to the surrounding Schwentine Estuary water. The opposite is observed for the extrapallial fluid (EPF). Our findings extend the results of previous studies reporting a strong biological control and the interaction of different environmental conditions influencing biomineralization. Future studies should focus on the temporal development of the interrelation between the different matrices.

Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the Moon.

PubMed

Schiller, Martin; Bizzarro, Martin; Fernandes, Vera Assis

2018-03-21

Nucleosynthetic isotope variability among Solar System objects is often used to probe the genetic relationship between meteorite groups and the rocky planets (Mercury, Venus, Earth and Mars), which, in turn, may provide insights into the building blocks of the Earth-Moon system. Using this approach, it has been inferred that no primitive meteorite matches the terrestrial composition and the protoplanetary disk material from which Earth and the Moon accreted is therefore largely unconstrained. This conclusion, however, is based on the assumption that the observed nucleosynthetic variability of inner-Solar-System objects predominantly reflects spatial heterogeneity. Here we use the isotopic composition of the refractory element calcium to show that the nucleosynthetic variability in the inner Solar System primarily reflects a rapid change in the mass-independent calcium isotope composition of protoplanetary disk solids associated with early mass accretion to the proto-Sun. We measure the mass-independent 48 Ca/ 44 Ca ratios of samples originating from the parent bodies of ureilite and angrite meteorites, as well as from Vesta, Mars and Earth, and find that they are positively correlated with the masses of their parent asteroids and planets, which are a proxy of their accretion timescales. This correlation implies a secular evolution of the bulk calcium isotope composition of the protoplanetary disk in the terrestrial planet-forming region. Individual chondrules from ordinary chondrites formed within one million years of the collapse of the proto-Sun reveal the full range of inner-Solar-System mass-independent 48 Ca/ 44 Ca ratios, indicating a rapid change in the composition of the material of the protoplanetary disk. We infer that this secular evolution reflects admixing of pristine outer-Solar-System material into the thermally processed inner protoplanetary disk associated with the accretion of mass to the proto-Sun. The identical calcium isotope composition of Earth and the Moon reported here is a prediction of our model if the Moon-forming impact involved protoplanets or precursors that completed their accretion near the end of the protoplanetary disk's lifetime.

Isotopic evolution of the protoplanetary disk and the building blocks of Earth and the Moon

NASA Astrophysics Data System (ADS)

Schiller, Martin; Bizzarro, Martin; Fernandes, Vera Assis

2018-03-01

Nucleosynthetic isotope variability among Solar System objects is often used to probe the genetic relationship between meteorite groups and the rocky planets (Mercury, Venus, Earth and Mars), which, in turn, may provide insights into the building blocks of the Earth–Moon system. Using this approach, it has been inferred that no primitive meteorite matches the terrestrial composition and the protoplanetary disk material from which Earth and the Moon accreted is therefore largely unconstrained. This conclusion, however, is based on the assumption that the observed nucleosynthetic variability of inner-Solar-System objects predominantly reflects spatial heterogeneity. Here we use the isotopic composition of the refractory element calcium to show that the nucleosynthetic variability in the inner Solar System primarily reflects a rapid change in the mass-independent calcium isotope composition of protoplanetary disk solids associated with early mass accretion to the proto-Sun. We measure the mass-independent 48Ca/44Ca ratios of samples originating from the parent bodies of ureilite and angrite meteorites, as well as from Vesta, Mars and Earth, and find that they are positively correlated with the masses of their parent asteroids and planets, which are a proxy of their accretion timescales. This correlation implies a secular evolution of the bulk calcium isotope composition of the protoplanetary disk in the terrestrial planet-forming region. Individual chondrules from ordinary chondrites formed within one million years of the collapse of the proto-Sun reveal the full range of inner-Solar-System mass-independent 48Ca/44Ca ratios, indicating a rapid change in the composition of the material of the protoplanetary disk. We infer that this secular evolution reflects admixing of pristine outer-Solar-System material into the thermally processed inner protoplanetary disk associated with the accretion of mass to the proto-Sun. The identical calcium isotope composition of Earth and the Moon reported here is a prediction of our model if the Moon-forming impact involved protoplanets or precursors that completed their accretion near the end of the protoplanetary disk’s lifetime.

Low-Risk Lifestyle, Coronary Calcium, Cardiovascular Events, and Mortality: Results From MESA

PubMed Central

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

2013-01-01

Unhealthy lifestyle habits are a major contributor to coronary artery disease. The purpose of the present study was to investigate the associations of smoking, weight maintenance, physical activity, and diet with coronary calcium, cardiovascular events, and mortality. US participants who were 44–84 years of age (n = 6,229) were followed in the Multi-Ethnic Study of Atherosclerosis from 2000 to 2010. A lifestyle score ranging from 0 to 4 was created using diet, exercise, body mass index, and smoking status. Coronary calcium was measured at baseline and a mean of 3.1 (standard deviation, 1.3) years later to assess calcium progression. Participants who experienced coronary events or died were followed for a median of 7.6 (standard deviation, 1.5) years. Participants with lifestyle scores of 1, 2, 3, and 4 were found to have mean adjusted annual calcium progressions that were 3.5 (95% confidence interval (CI): 0.0, 7.0), 4.2 (95% CI: 0.6, 7.9), 6.8 (95% CI: 2.0, 11.5), and 11.1 (95% CI: 2.2, 20.1) points per year slower, respectively, relative to the reference group (P = 0.003). Unadjusted hazard ratios for death by lifestyle score were as follows: for a score of 1, the hazard ratio was 0.79 (95% CI: 0.61, 1.03); for a score of 2, the hazard ratio was 0.61 (95% CI: 0.46, 0.81); for a score of 3, the hazard ratio was 0.49 (95% CI: 0.32, 0.75); and for a score of 4, the hazard ratio was 0.19 (95% CI: 0.05, 0.75) (P < 0.001 by log-rank test). In conclusion, a combination of regular exercise, healthy diet, smoking avoidance, and weight maintenance was associated with lower coronary calcium incidence, slower calcium progression, and lower all-cause mortality over 7.6 years. PMID:23733562

Calcium and strontium isotope fractionation in aqueous solutions as a function of temperature and reaction rate; I. Calcite

NASA Astrophysics Data System (ADS)

AlKhatib, Mahmoud; Eisenhauer, Anton

2017-07-01

In order to study Strontium (Sr) partitioning and isotope fractionation of Sr and Calcium (Ca) in calcite we performed precipitation (T) experiments decoupling temperature and precipitation rate (R∗). Calcite was precipitated at 12.5, 25.0 and 37.5 °C by diffusing NH3 and CO2 gases into aqueous solutions closely following the experimental setup of Lemarchand et al. (2004). The precipitation rate (R∗) for every sample was determined applying the initial rate method and from the specific surface area of almost all samples for each reaction. The order of reaction with respect to Ca2+ ions was determined to be one and independent of T. However, the order of reaction with respect to HCO3- changed from three to one as temperature increases from 12.5, 25 °C and 37.5 °C. Strontium incorporated into calcite (expressed as DSr = [Sr/Ca]calcite/[Sr/Ca]solution) was found to be R∗ and T dependent. As a function of increasing R∗ the Δ88/86Sr-values become more negative and as temperature increases the Δ88/86Sr values also increase at constant R∗. The DSr and Δ88/86Sr-values are correlated to a high degree and depend only on R∗ being independent of temperature, complexation and varying initial ratios. Latter observation may have important implications for the study of diagenesis, the paleo-sciences and the reconstruction of past environmental conditions. Calcium isotope fractionation (Δ44/40Ca) was also found to be R∗ and T dependent. For 12.5 and 25.0 °C we observe a general increase of the Δ44/40Ca values as a function of R∗ (Lemarchand et al. type behavior, Lemarchand et al. (2004)). Whereas at 37.5 °C a significant decreasing Δ44/40Ca is observed relative to increasing R∗ (Tang et al. type behavior, Tang et al. (2008)). In order to reconcile the discrepant observations we suggest that the temperature triggered change from a Ca2+-NH3-aquacomplex covalent controlled bonding to a Ca2+-H2O-aquacomplex van-der-Waals controlled bonding caused the change in sign of the R∗ - Δ44/40Ca slope due to the switch of an equilibrium type of isotope fractionation related to the covalent bonding during lower temperatures to a kinetic type of isotope fractionation at higher temperatures. This is supported by the observation that the Δ44/40Ca ratios tend to depend on the [Ca]:[DIC] ratio at 12.5 and 25 °C but is highly independent at 37.5 °C. Our observations imply the chemical fluid composition and temperature dependent complexation controls the amount and direction of Ca isotope fractionation in contrast to the Sr isotopes which do not show any change of its fractionation behavior as a function of complexation in the liquid phase.

An improved method for emergent decontamination of ocular and dermal hydrofluoric acid splashes.

PubMed

Soderberg, Kjell; Kuusinen, Petri; Mathieu, Laurence; Hall, Alan H

2004-08-01

Accidental hydrofluoric acid (HF) splashes often occur in industrial settings. HF easily penetrates into tissues by initial acid action allowing fluoride ions to penetrate deeply, chelating calcium and magnesium. Resultant hypocalcemia and hypomagnesemia can be fatal. This report describes the utilization of Hexafluorine--a hypertonic, amphoteric, chelating decontamination solution--in workplaces where water decontamination followed by calcium gluconate inunction failed to prevent HF burns and systemic toxicity. Between 1998 and 1999, 16 cases of ocular and dermal HF splashes with either 70% HF or 6% HF/15% nitric acid (HNO3) were decontaminated with Hexafluorine at the worksite. HF burns did not develop and medical treatment other than initial decontamination was not reQuired in 12/16 (75%). In 7/16 (44%) cases, lost work time corresponded to duration of hospital observation (mean < 1 d).

Single-Dose Absorption and Pharmacokinetics of WR 6026. Phase 1

DTIC Science & Technology

1988-08-01

glucose, uric acid , calcium, phosphate, 8 total protein, albumin, direct and total bilirubin, aspartate aminotransferase (AST), alanine aminotransferase...Fitted Equation 42 Table 8 Elimination Rate Constant and Plasma Half-Life of WK 6026 43 Table 9 Pharmacokinetic Data for Individual Subjects 44 Table 10...failure rate of antimony compounds and the toxicity of other effective drugs, there is a clear need for development of alternative drugs. WR 6026 (8-(6

Measurement of isotope ratio of Ca{sup +} ions in a linear Paul Trap

DOE Office of Scientific and Technical Information (OSTI.GOV)

Hashimoto, Y.; Minamino, K.; Nagamoto, D.

2009-03-17

Measurement of isotope ratios of Calcium is very useful in many fields. So we demonstrated the measurement of isotope ratios of {sup 40}Ca{sup +}(abundance 96.4%) to {sup 44}Ca{sup +}(2.09%) ions in a linear Paul trap with several laser lights tuning to the isotope shifts. And we found that the experimental parameters had large influences on the measurement of the isotope ratios.

A mutation in the extracellular domain of the α7 nAChR reduces calcium permeability.

PubMed

Colón-Sáez, José O; Yakel, Jerrel L

2014-08-01

The α7 neuronal nicotinic acetylcholine receptor (nAChR) displays the highest calcium permeability among the different subtypes of nAChRs expressed in the mammalian brain and can impact cellular events including neurotransmitter release, second messenger cascades, cell survival, and apoptosis. The selectivity for cations in nAChRs is thought to be achieved in part by anionic residues which are located on either side of the channel mouth and increase relative cationic concentration. Mutagenesis studies have improved our understanding of the role of the second transmembrane domain and the intracellular loop of the channel in ion selectivity. However, little is known about the influence that the extracellular domain (ECD) plays in ion permeation. In the α7 nAChR, it has been found that the ECD contains a ring of ten aspartates (two per subunit) that is believed to face the lumen of the pore and could attract cations for permeation. Using mutagenesis and a combination of electrophysiology and imaging techniques, we tested the possible involvement of these aspartate residues in the calcium permeability of the rat α7 nAChR. We found that one of these residues (the aspartate at position 44) appears to be essential since mutating it to alanine resulted in a decrease in amplitude for both whole cell and single-channel responses and in the complete disappearance of detectable calcium changes in most cells, which indicates that the ECD of the α7 nAChR plays a key role in calcium permeation.

A mutation in the extracellular domain of the α7 nAChR reduces calcium permeability

PubMed Central

Colón-Sáez, José O.

2013-01-01

The α7 neuronal nicotinic acetylcholine receptor (nAChR) displays the highest calcium permeability among the different subtypes of nAChRs expressed in the mammalian brain and can impact cellular events including neurotransmitter release, second messenger cascades, cell survival, and apoptosis. The selectivity for cations in nAChRs is thought to be achieved in part by anionic residues which are located on either side of the channel mouth and increase relative cationic concentration. Mutagenesis studies have improved our understanding of the role of the second transmembrane domain and the intracellular loop of the channel in ion selectivity. However, little is known about the influence that the extracellular domain (ECD) plays in ion permeation. In the α7 nAChR, it has been found that the ECD contains a ring of ten aspartates (two per subunit) that is believed to face the lumen of the pore and could attract cations for permeation. Using mutagenesis and a combination of electrophysiology and imaging techniques, we tested the possible involvement of these aspartate residues in the calcium permeability of the rat α7 nAChR. We found that one of these residues (the aspartate at position 44) appears to be essential since mutating it to alanine resulted in a decrease in amplitude for both whole cell and single-channel responses and in the complete disappearance of detectable calcium changes in most cells, which indicates that the ECD of the α7 nAChR plays a key role in calcium permeation. PMID:24177919

ANSL-V: ENDF/B-V based multigroup cross-section libraries for Advanced Neutron Source (ANS) reactor studies. Supplement 1

DOE Office of Scientific and Technical Information (OSTI.GOV)

Wright, R.Q.; Renier, J.P.; Bucholz, J.A.

1995-08-01

The original ANSL-V cross-section libraries (ORNL-6618) were developed over a period of several years for the physics analysis of the ANS reactor, with little thought toward including the materials commonly needed for shielding applications. Materials commonly used for shielding applications include calcium barium, sulfur, phosphorous, and bismuth. These materials, as well as {sup 6}Li, {sup 7}Li, and the naturally occurring isotopes of hafnium, have been added to the ANSL-V libraries. The gamma-ray production and gamma-ray interaction cross sections were completely regenerated for the ANSL-V 99n/44g library which did not exist previously. The MALOCS module was used to collapse the 99n/44gmore » coupled library to the 39n/44g broad- group library. COMET was used to renormalize the two-dimensional (2- D) neutron matrix sums to agree with the one-dimensional (1-D) averaged values. The FRESH module was used to adjust the thermal scattering matrices on the 99n/44g and 39n/44g ANSL-V libraries. PERFUME was used to correct the original XLACS Legendre polynomial fits to produce acceptable distributions. The final ANSL-V 99n/44g and 39n/44g cross-section libraries were both checked by running RADE. The AIM module was used to convert the master cross-section libraries from binary coded decimal to binary format (or vice versa).« less

The contribution of dairy products to micronutrient intake in the Netherlands.

PubMed

Vissers, Pauline A J; Streppel, Martinette T; Feskens, Edith J M; de Groot, Lisette C P G M

2011-10-01

To assess the contribution of dairy products to the intake of various vitamins and minerals in several life stages in the Dutch population. Data from 3 Dutch Food Consumption Surveys and the Leiden Longevity Study were used to estimate the contribution of dairy products--as percentage of total intake--to the intake of iron, copper, selenium, zinc, calcium, folic acid, vitamin D, vitamin C, and vitamin B(12). In young children, dairy products contributed substantially to the intake of calcium (73%), selenium (21%), iron (8%), zinc (39%), copper (12%), folic acid (24%), vitamin C (18%), vitamin D (16%), and vitamin B(12) (58%). Of all dairy products, milk contributed the most to the intake of these nutrients. In adults and elderly subjects, the contribution of dairy products to total micronutrient intake was 65%-68% for calcium, 18%-19% for selenium, 3%-4% for iron, 28%-31% for zinc, 6%-7% for copper, 17%-19% for folic acid, 10%-14% for vitamin C, 11%-16% for vitamin D, and 44%-46% for vitamin B(12). Milk as well as cheese contributed the most to the intake of these nutrients. Dairy products are an important source of vitamins and minerals in the Dutch population. Dairy products, especially milk and cheese, contribute substantially to the intake of calcium, selenium, zinc, and vitamin B(12).

High precision calcium isotope analysis using 42Ca-48Ca double-spike TIMS technique

NASA Astrophysics Data System (ADS)

Feng, L.; Zhou, L.; Gao, S.; Tong, S. Y.; Zhou, M. L.

2014-12-01

Double spike techniques are widely used for determining calcium isotopic compositions of natural samples. The most important factor controlling precision of the double spike technique is the choice of appropriate spike isotope pair, the composition of double spikes and the ratio of spike to sample（CSp/CN）. We propose an optimal 42Ca-48Ca double spike protocol which yields the best internal precision for calcium isotopic composition determinations among all kinds of spike pairs and various spike compositions and ratios of spike to sample, as predicted by linear error propagation method. It is suggested to use spike composition of 42Ca/(42Ca+48Ca) = 0.44 mol/mol and CSp/(CN+ CSp)= 0.12mol/mol because it takes both advantages of the largest mass dispersion between 42Ca and 48Ca (14%) and lowest spike cost. Spiked samples were purified by pass through homemade micro-column filled with Ca special resin. K, Ti and other interference elements were completely separated, while 100% calcium was recovered with negligible blank. Data collection includes integration time, idle time, focus and peakcenter frequency, which were all carefully designed for the highest internal precision and lowest analysis time. All beams were automatically measured in a sequence by Triton TIMS so as to eliminate difference of analytical conditions between samples and standards, and also to increase the analytical throughputs. The typical internal precision of 100 duty cycles for one beam is 0.012‒0.015 ‰ (2δSEM), which agrees well with the predicted internal precision of 0.0124 ‰ (2δSEM). Our methods improve internal precisions by a factor of 2‒10 compared to previous methods of determination of calcium isotopic compositions by double spike TIMS. We analyzed NIST SRM 915a, NIST SRM 915b and Pacific Seawater as well as interspersed geological samples during two months. The obtained average δ44/40Ca (all relative to NIST SRM 915a) is 0.02 ± 0.02 ‰ (n=28), 0.72±0.04 ‰ (n=10) and 1.93±0.03 ‰ (n=21) for NIST SRM 915a, NIST SRM 915b and Pacific Seawater, respectively. The long-term reproducibility is 0.10‰ (2 δSD), which is comparable to the best external precision of 0.04 ‰ (2 δSD) of previous methods, but our sample throughputs are doubled with significant reduction in amount of spike used for single samples.

DOE Office of Scientific and Technical Information (OSTI.GOV)

Silva, Camila F.N.; Lazarin, Angélica M., E-mail: amlazarin2@uem.br; Sernaglia, Rosana L.

Graphical abstract: Scanning electron microscopy photographs of calcium phosphate (a) and intercalated with p-aminobenzoic acid (b). Highlights: ► Calcium phosphate was intercalated with p-aminobenzoic acid. ► Guest molecule contains nitrogen and oxygen atoms from amine and carboxylic groups. ► These basic centers are potentially useful for cation coordination in ethanol solution. ► Crystal morphology of compounds is lamellar, it agrees with expected structural characteristics. -- Abstract: Crystalline lamellar calcium phosphate retained 4-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1033 and 1010 cm{sup −1} interval confirmed the presence of the phosphonate groups attached to themore » inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 712 and 1578 pm for the original and the intercalated compounds, respectively. Solid-state {sup 31}P nuclear magnetic resonance spectra presented only one peak for the phosphate groups attached to the main inorganic polymeric structure near −2.4 ppm. The adsorption isotherms from ethanol gave the maximum adsorption capacities of 6.44 and 3.34 mmol g{sup −1} for nickel and cobalt, respectively, which stability constant and distribution coefficient followed Co > Ni.« less

Transmission electron microscopy of coatings formed by plasma electrolytic oxidation of titanium.

PubMed

Matykina, E; Arrabal, R; Skeldon, P; Thompson, G E

2009-05-01

Transmission electron microscopy and supporting film analyses are used to investigate the changes in composition, morphology and structure of coatings formed on titanium during DC plasma electrolytic oxidation in a calcium- and phosphorus-containing electrolyte. The coatings are of potential interest as bioactive surfaces. The initial barrier film, of mixed amorphous and nanocrystalline structure, formed below the sparking voltage of 180 V, incorporates small amounts of phosphorus and calcium species, with phosphorus confined to the outer approximately 63% of the coating thickness. On commencement of sparking, calcium- and phosphorus-rich amorphous material forms at the coating surface, with local heating promoting crystallization in underlying and adjacent anodic titania. The amorphous material thickens with increased treatment time, comprising almost the whole of the approximately 5.7-microm-thick coating formed at 340 V. At this stage, the coating is approximately 4.4 times thicker than the oxidized titanium, with a near-surface composition of about 12 at.% Ti, 58 at.% O, 19 at.% P and 11 at.% Ca. Further, the amount of titanium consumed in forming the coating is similar to that calculated from the anodizing charge, although there may be non-Faradaic contributions to the coating growth.

Complexity of nearshore strontium-to-calcium ratio variability in a core sample of the massive coral Siderastrea siderea obtained in Coral Bay, St. John, U.S. Virgin Islands

USGS Publications Warehouse

Reich, Christopher D.; Kuffner, Ilsa B.; Hickey, T. Don; Morrison, Jennifer M.; Flannery, Jennifer A.

2013-01-01

Strontium-to-calcium ratios (Sr/Ca) were measured on the skeletal matrix of a core sample from a colony of the massive coral Siderastrea siderea collected in Coral Bay, St. John, U.S. Virgin Islands. Strontium and calcium are incorporated into the coral skeleton during the precipitation of aragonite by the coral polyps and their ratio is highly temperature dependent. The robustness of this temperature dependence makes Sr/Ca a reliable proxy for sea surface temperature (SST). Details presented from the St. John S. siderea core indicate that terrestrial inputs of sediment and freshwater can disrupt the chemical balance and subsequently complicate the utility of Sr/Ca in reconstructing historical SST. An approximately 44-year-long record of Sr/Ca shows that an annual SST signal is recorded but with an increasing Sr/Ca trend from 1980 to present, which is likely the result of runoff from the mountainous terrain of St. John. The overwhelming influence of the terrestrial fingerprint on local seawater chemistry makes utilizing Sr/Ca as a SST proxy in nearshore environments very difficult.

Antileishmanial activity and ultrastructural alterations of Leishmania (L.) chagasi treated with the calcium channel blocker nimodipine.

PubMed

Tempone, André Gustavo; Taniwaki, Noemi Nosomi; Reimão, Juliana Quero

2009-08-01

In a search for novel antileishmanial drugs, we investigated the activity of the calcium channel blocker nimodipine against Leishmania spp. and explored the ultrastructural damages of parasites induced by nimodipine after a short period of incubation. Nimodipine was highly effective against promastigotes and intracellular amastigotes of Leishmania (L.) chagasi, with 50% inhibitory concentration values of 81.2 and 21.5 muM, respectively. Nimodipine was about fourfold more effective than the standard pentavalent antimony against amastigotes and showed a Selectivity Index of 4.4 considering its mammalian cells toxicity. Leishmania (L.) amazonensis and Leishmania (L.) major promastigotes were also susceptible to nimodipine in a range concentration between 31 and 128 muM. Ultrastructural studies of L. (L.) chagasi revealed intense mitochondria damage and plasma membrane blebbing, resulting in a leishmanicidal effect as demonstrated by the lack of mitochondrial oxidative metabolism. The amastigote-killing effect suggests other mechanism than macrophage activation, as no upregulation of nitric oxide was seen. This calcium channel blocker is an effective in vitro antileishmanial compound and if adequately studied could be used as a novel drug candidate or as a novel drug lead compound for drug design studies against leishmaniasis.

Receptor activator of nuclear factor kappa β ligand (RANKL) and its relationship to coronary atherosclerosis in HIV patients

PubMed Central

Hwang, Janice J.; Wei, Jeffrey; Abbara, Suhny; Grinspoon, Steven K.; Lo, Janet

2013-01-01

HIV-infected individuals have an increased prevalence of coronary artery disease (CAD). Receptor activator of nuclear factor kappa β ligand (RANKL) and osteoprotegerin (OPG) have been postulated as mediators of vascular calcification. 78 HIV-infected men and 32 healthy controls without history of CAD were prospectively recruited to undergo cardiac computed tomography (CT) and CT angiography to assess coronary artery calcium and plaque burden. sRANKL was lower in HIV-infected individuals than controls (2.52 [1.08, 3.98] vs. 3.33 [2.44, 4.64] pg/ml, P=0.01, median [IQR] respectively). sRANKL was negatively associated with the number of coronary segments with plaque (Spearman ρ=−0.41, P<0.001) and Agatston calcium score (ρ=−0.30, P<0.01) in HIV-infected individuals even after adjusting for traditional cardiovascular risk factors. PMID:22842843

Seasonal variations in the macronutrient mineral and proximate composition of two clams (Chamelea gallina and Donax trunculus).

PubMed

Ozden, Ozkan; Erkan, Nuray; Ulusoy, Safak

2009-08-01

Two bivalve's species (Chamelea gallina and Donax trunculus) were investigated in terms of proximate and mineral compositions (sodium, potassium, magnesium, calcium, iodine and selenium) throughout the year. The concentrations of minerals were determined using inductively coupled plasma mass spectrometry. Ranges of moisture, protein, fat, ash and carbohydrate contents were 82.70-86.57%, 6.86-8.99%, 0.58-1.20%, 2.44-2.95% and 2.70-4.50% for C. gallina, and were 81.09-85.55%, 8.13-10.61%, 0.69-1.33%, 3.19-4.06% and 2.31-3.18% for D. trunculus, respectively. The highest sodium, potassium, magnesium, calcium, iodine and selenium contents for two species were found in the summer, followed by spring, autumn and winter. The concentrations of metals in two tissues exceeded the acceptable levels for a food source for human consumption.

Determinants of calcium and oxalate excretion in subjects with calcium nephrolithiasis: the role of metabolic syndrome traits.

PubMed

Ticinesi, Andrea; Guerra, Angela; Allegri, Franca; Nouvenne, Antonio; Cervellin, Gianfranco; Maggio, Marcello; Lauretani, Fulvio; Borghi, Loris; Meschi, Tiziana

2018-06-01

The association of metabolic syndrome (MetS) traits with urinary calcium (UCE) or oxalate excretion (UOE) is uncertain in calcium stone formers (CSFs). Our aim was to investigate this association in a large group of Caucasian CSFs. We retrospectively reviewed data of CSFs evaluated at our Kidney Stone Clinic from 1984 to 2015. Data on body mass index (BMI), MetS traits defined according to international consensus, family history of urolithiasis, anti-hypertensive treatments, calcemia, renal function, and 24-h urinary profile of lithogenic risk were collected. The association between MetS traits and UCE or UOE was tested with multivariate linear regression models accounting for a long list of potential confounders. We included 3003 CSFs, aged 44 ± 14 years. The prevalence of hypertension, diabetes, overweight (BMI ≥ 25 kg/m 2 ) and dyslipidemia was 17, 2, 42 and 38%, respectively. Median values of UCE and UOE were 211 mg/24 h (IQR 143-296) and 28 mg/24 h (IQR 22-34), respectively. At a multivariate model, including age, sex, date of examination, drug treatments, family history, renal function, blood calcium and urinary factors as covariates, hypertension was a significant positive determinant of UCE (β ± SE 0.23 ± 0.07, p = 0.003), but overweight, dyslipidemia and diabetes were not. No MetS trait was significantly associated with UOE in multivariate models. In a large group of Caucasian CSFs, hypertension was the only MetS trait significantly associated with UCE, while no MetS trait was associated with oxalate excretion.

Determination of serum calcium levels by 42Ca isotope dilution inductively coupled plasma mass spectrometry.

PubMed

Han, Bingqing; Ge, Menglei; Zhao, Haijian; Yan, Ying; Zeng, Jie; Zhang, Tianjiao; Zhou, Weiyan; Zhang, Jiangtao; Wang, Jing; Zhang, Chuanbao

2017-11-27

Serum calcium level is an important clinical index that reflects pathophysiological states. However, detection accuracy in laboratory tests is not ideal; as such, a high accuracy method is needed. We developed a reference method for measuring serum calcium levels by isotope dilution inductively coupled plasma mass spectrometry (ID ICP-MS), using 42Ca as the enriched isotope. Serum was digested with 69% ultrapure nitric acid and diluted to a suitable concentration. The 44Ca/42Ca ratio was detected in H2 mode; spike concentration was calibrated by reverse IDMS using standard reference material (SRM) 3109a, and sample concentration was measured by a bracketing procedure. We compared the performance of ID ICP-MS with those of three other reference methods in China using the same serum and aqueous samples. The relative expanded uncertainty of the sample concentration was 0.414% (k=2). The range of repeatability (within-run imprecision), intermediate imprecision (between-run imprecision), and intra-laboratory imprecision were 0.12%-0.19%, 0.07%-0.09%, and 0.16%-0.17%, respectively, for two of the serum samples. SRM909bI, SRM909bII, SRM909c, and GBW09152 were found to be within the certified value interval, with mean relative bias values of 0.29%, -0.02%, 0.10%, and -0.19%, respectively. The range of recovery was 99.87%-100.37%. Results obtained by ID ICP-MS showed a better accuracy than and were highly correlated with those of other reference methods. ID ICP-MS is a simple and accurate candidate reference method for serum calcium measurement and can be used to establish and improve serum calcium reference system in China.

Status of serum-calcium and -albumin measurement in Argentina assessed in 300 representative laboratories with 20 fresh frozen single donation sera.

PubMed

Stepman, Hedwig C M; Stöckl, Dietmar; Acheme, Rosana; Sesini, Sandra; Mazziotta, Daniel; Thienpont, Linda M

2011-11-01

The Fundación Bioquímica Argentina (FBA) performs external quality assessment (EQA) of >3200 laboratories. However, FBA realizes that sample non-commutability and predominant use of heterogeneous systems may bias the estimated performance and standardization status. To eliminate these confounding factors, a study using frozen single donation sera was undertaken with the focus on serum-calcium and -albumin measurement. Target values were established from the results produced with homogeneous systems. In groups of n=7, system effects were investigated. Laboratory performance was evaluated from the correlation coefficient r between the measurement results for all sera and the target values. This allowed ranking of the laboratories and judgment of the deviation for individual samples (total error) against a 10% limit. The total error specification was a deviation for ≥ 5 samples exceeding 10% and/or causing a result outside the laboratory's reference interval. For calcium (n=303) (range: 2.06-2.42 mmol/L), 81 laboratories had an r-value <0.6, 43 even <0.4; the total error was relevant for 97 (10% limit) and 111 (reference interval) laboratories. For albumin (n=311) (range: 34.7-45.7 g/L) r was <0.7 (<0.4) in 44 (16) laboratories; 83 and 36 laboratories exceeded the total error criteria. Laboratories using homogeneous systems were generally ranked higher by correlation. System effects were moderate for calcium, but significant for albumin. The study demonstrated the need to improve the quality and harmonization of calcium and albumin testing in the investigated laboratories. To achieve this objective, we promote co-operation between laboratories, EQA provider and manufacturers.

Physical performance and life quality in postmenopausal women supplemented with vitamin D: a two-year prospective study

PubMed Central

Gao, Li-hong; Zhu, Wen-jun; Liu, Yu-juan; Gu, Jie-mei; Zhang, Zhen-lin; Wang, Ou; Xing, Xiao-ping; Xu, Ling

2015-01-01

Aim: To investigate the effects of calcium and vitamin D supplementation on bone turnover marker levels, muscle strength and quality of life in postmenopausal Chinese women. Methods: A total of 485 healthy postmenopausal Chinese women (63.44±5.04 years) were enrolled in this open-label, 2-year, prospective, community-based trial. The participants were divided into group A, B, C, which were treated with calcium (600 mg/d) alone, calcium (600 mg/d) and cholecalciferol (800 IU/d) or calcium (600 mg/d) and calcitriol (0.25 μg/d), respectively, for 2 years. Serum levels of 25-hydroxyvitamin D, parathyroid hormone, β-CTX and P1NP were measured, and the muscle strength and quality of life were assessed at baseline and at 12- and 24-month follow-ups. Results: Four hundred and sixty one participants completed this study. Serum levels of 25-hydroxyvitamin D were significantly increased in group C, but not changed in groups A and B at 24-month follow-up. Serum levels of parathyroid hormone, bone turnover marker β-CTX and bone formation marker P1NP were significantly decreased in group C, while serum levels of β-CTX were increased in group A at 24-month follow-up. The participants in group C maintained the grip strength, while those in groups A and B exhibited decreased grip strength at 24-month follow-up. The quality of life for the participants in groups B and C remained consistent, but that in group A was deteriorated at 24-month follow-up. Conclusion: Supplementation with calcitriol and calcium modifies the bone turnover marker levels, and maintains muscle strength and quality of life in postmenopausal Chinese women, whereas supplementation with cholecalciferol and calcium prevents aging-mediated deterioration in quality of life. PMID:26279157

Purification, crystallization and preliminary X-ray diffraction of human S100A15

DOE Office of Scientific and Technical Information (OSTI.GOV)

Boeshans, Karen M.; Wolf, Ronald; Voscopoulos, Christopher

2006-05-01

S100 proteins are differentially expressed during epithelial cell maturation, tumorigenesis and inflammation. The novel human S100A15 protein has been cloned, expressed, purified and crystallized in two crystal forms, a triclinic and a monoclinic form, which diffract to 1.7 and 2.0 Å, respectively. Human S100A15 is a novel member of the S100 family of EF-hand calcium-binding proteins and was recently identified in psoriasis, where it is significantly upregulated in lesional skin. The protein is implicated as an effector in calcium-mediated signal transduction pathways. Although its biological function is unclear, the association of the 11.2 kDa S100A15 with psoriasis suggests that itmore » contributes to the pathogenesis of the disease and could provide a molecular target for therapy. To provide insight into the function of S100A15, the protein was crystallized to visualize its structure and to further the understanding of how the many similar calcium-binding mediator proteins in the cell distinguish their cognate target molecules. The S100A15 protein has been cloned, expressed and purified to homogeneity and produced two crystal forms. Crystals of form I are triclinic, with unit-cell parameters a = 33.5, b = 44.3, c = 44.8 Å, α = 71.2, β = 68.1, γ = 67.8° and an estimated two molecules in the asymmetric unit, and diffract to 1.7 Å resolution. Crystals of form II are monoclinic, with unit-cell parameters a = 82.1, b = 33.6, c = 52.2 Å, β = 128.2° and an estimated one molecule in the asymmetric unit, and diffract to 2.0 Å resolution. This structural analysis of the human S100A15 will further aid in the phylogenic comparison between the other members of the S100 protein family, especially the highly homologous paralog S100A7.« less

A grape-enriched diet increases bone calcium retention and cortical bone properties in ovariectomized rats.

PubMed

Hohman, Emily E; Weaver, Connie M

2015-02-01

Grapes and their associated phytochemicals have been investigated for beneficial effects on cardiovascular health, cancer prevention, and other chronic diseases, but the effect of grape consumption on bone health has not been fully determined. We previously found short-term benefits of grape products on reducing bone turnover in ovariectomized rats. The objective of this study was to determine the long-term benefits of a grape-enriched diet on bone in ovariectomized rats. Rats were ovariectomized at 3 mo of age and were administered a single dose of (45)Ca to prelabel bones at 4 mo of age. After a 1-mo equilibration period, baseline urinary (45)Ca excretion was determined. Rats (n = 22/group) were then randomly assigned to a modified AIN93M diet containing 25% freeze-dried grape powder or to a control diet for 8 wk. Urinary (45)Ca excretion was monitored throughout the study to determine changes in bone (45)Ca retention. Calcium balance was assessed after 1 and 8 wk of consuming the experimental diets, and a calcium kinetic study was performed at 8 wk. After 8 wk, femurs were collected for micro-computed tomographic imaging, 3-point bending, and reference point indentation. Rats fed the grape-enriched diet had 44% greater net bone calcium retention than did rats fed the control diet. There were no differences in calcium balance due to diet at either week 1 or week 8, but there was a significant increase in net calcium absorption (10.6%) and retention (5.7%) from week 1 to week 8 in the grape-enriched diet group only. Grape-enriched diet-fed rats had 3% greater cortical thickness and 11% greater breaking strength. There were no differences in femur bone mineral density, trabecular microarchitecture, or reference point indentation variables due to diet. This study of ovariectomized rats indicates that the consumption of grape products may improve calcium utilization and suppress bone turnover, resulting in improvements in bone quality. © 2015 American Society for Nutrition.

Assessing human weaning practices with calcium isotopes in tooth enamel

PubMed Central

Tacail, Théo; Thivichon-Prince, Béatrice; Martin, Jeremy E.; Charles, Cyril; Viriot, Laurent

2017-01-01

Weaning practices differ among great apes and likely diverged during the course of human evolution, but behavioral inference from the fossil record is hampered by a lack of unambiguous biomarkers. Here, we show that early-life dietary transitions are recorded in human deciduous tooth enamel as marked variations in Ca isotope ratios (δ44/42Ca). Using a sequential microsampling method along the enamel growth axis, we collected more than 150 enamel microsamples from 51 deciduous teeth of 12 different modern human individuals of known dietary histories, as well as nine enamel samples from permanent third molars. We measured and reconstructed the evolution of 44Ca/42Ca ratios in enamel from in utero development to first months of postnatal development. We show that the observed variations of δ44/42Ca record a transition from placental nutrition to an adult-like diet and that Ca isotopes reflect the duration of the breastfeeding period experienced by each infant. Typically, the δ44/42Ca values of individuals briefly or not breastfed show a systematic increase during the first 5–10 mo, whereas individuals with long breastfeeding histories display no measurable variation in δ44/42Ca of enamel formed during this time. The use of Ca isotope analysis in tooth enamel allows microsampling and offers an independent approach to tackle challenging questions related to past population dynamics and evolution of weaning practices in hominins. PMID:28559355

44Ca doped remineralization study on dentin by isotope microscopy.

PubMed

Hiraishi, N; Kobayashi, S; Yurimoto, H; Tagami, J

2018-04-01

The dental caries is developed as a result of an alternative course of mineral gain and loss. In order to distinguish between intrinsic Ca (tooth-derived mineral) and extrinsic Ca (solution-derived mineral) uptakes, a 44 Ca doped pH-cycling was performed using 44 Ca (a stable calcium isotope) remineralization solution. The natural abundance of 40 Ca and 44 Ca is 96.9% and 2.1%, respectively. The remineralization solution was prepared using 44 Ca to contain 1.5mmol/L CaCl 2 ( 44 Ca), 0.9mmol/L KH 2 PO 4, 130mmol/L KCl, 20mmol/L HEPES at pH 7.0. The pH-cycling was conducted on bovine root dentin daily by demineralization (pH 5.0) for 2h, incubation in 0% (control) and 0.2% NaF (900ppm fluoride) for 2h and 44 Ca doped remineralization for 20h. After 14days pH-cycling, the specimens were sectioned longitudinally. On the sectioned surface, isotope imaging of 40 Ca and 44 Ca labeled mineral distribution was observed by a high mass-resolution stigmatic secondary ion 77 (Camera IMS 1270, Gennevilliers Cedex, France). Uptake of 44 Ca was greater in intensity for the 0.2% fluoride group than the control, especially in the superficial lesions. The control group showed 40 Ca (intrinsic) distribution in the subsurface lesions and in the superficial lesions, meanwhile the fluoride group showed 40 Ca distribution limited in subsurface lesions. The total Ca ( 44 Ca+ 40 Ca) image revealed more homogeneously for the control than the fluoride group. Since the fluoride-treated surface is more acid-resistant than intrinsic dentin, alternative minerals were dissolved from the intact intrinsic lesion in the demineralization cycle. Copyright © 2018 The Academy of Dental Materials. Published by Elsevier Ltd. All rights reserved.

[Prevalence and quality of control of calcium and phosphorus metabolism disorders among Lithuanian hemodialysis patients in 2004 and 2005].

PubMed

Petrauskiene, Vaida; Ziginskiene, Edita; Kuzminskis, Vytautas; Burciuviene, Asta; Grazulis, Saulius; Sileikiene, Elvyra; Masalskiene, Jūrate; Juodeikiene, Laima; Tamosaitis, Donatas; Alisauskiene, Violeta

2007-01-01

The aim of the study was to determine the prevalence and quality of control of disorders of calcium and phosphorus metabolism among patients on hemodialysis in Lithuania during the period of 2004-2005 and to assess rarely used methods of treatment such as parathyroidectomy and administration of calcimimetics. All Lithuanian hemodialysis centers were visited, and data on disorders of calcium-phosphorus metabolism were collected in December 2004 and 2005. The quality of control was evaluated according to Kidney Disease Outcome Quality Initiative recommendations. According to Kidney Disease Outcome Quality Initiative guidelines, normal parathyroid hormone levels were found in 20.4% of hemodialysis patients in 2004 and 18.8% of hemodialysis patients in 2005; normal levels of phosphate were in 41.9% and 39.4%, respectively; normal levels of calcium were observed in 44.7% of patients in 2004 and in 42.3% of patients in 2005. In 2005 as compared to 2004, there were statistically significantly more patients with low parathyroid hormone level (39.9% and 45.8%, respectively, P<0.05). Only in 5.6% of patients in 2004 and 3.9% of patients in 2005, all four parameters of calcium-phosphate metabolism (calcium, phosphate, and of parathyroid hormone levels and calcium-phosphate product) were within the normal range. No parameters in the normal range were found in 17-20% of patients. The use of alfacalcidol significantly increased: 316 (30.8%) patients in 2004 and 388 (35.7%) patients in 2005 were treated with alfacalcidol (P<0.05). Alfacalcidol was prescribed for 16.5% of patients in 2004 and for 17% of patients in 2005, in whom parathyroid hormone level was below the normal range in the presence of hypercalcemia and hyperphosphatemia. The use of calcimimetics was considered rational in 142 (13.8%) patients in 2004 and 119 (10.9%) patients in 2005. According to the data of our study, parathyroidectomy was indicated in 19 (1.85%) patients in 2004 and 17 (1.56%) patients in 2005. According to Kidney Disease Outcome Quality Initiative recommendations, the control of disorders of calcium-phosphate metabolism in Lithuanian hemodialysis patients was insufficient in 2004 and 2005. One-third of the patients were treated with alfacalcidol when parathyroid hormone level was low and hypercalcemia and hyperphosphatemia persisted. Calcimimetics for the treatment of secondary hyperparathyroidism were administered in about 10% of patients.

Therapy of Hypoparathyroidism With PTH(1–84): A Prospective Six Year Investigation of Efficacy and Safety

PubMed Central

Cusano, Natalie E.; Fan, Wen-Wei; Delgado, Yasmine; Zhang, Chengchen; Costa, Aline G.; Cremers, Serge; Dworakowski, Elzbieta; Bilezikian, John P.

2016-01-01

Context: Human recombinant (rh)PTH(1–84) was recently approved for the treatment of refractory hypoparathyroidism, based upon a short-term phase 3 clinical trial. Long-term data are needed, because no time limit was placed on the treatment period. Objective: We studied the effect of long-term rhPTH(1–84) treatment in hypoparathyroidism for up to 6 years. Design: Prospective open-label study. Setting: Referral center. Patients: A total of 33 subjects with hypoparathyroidism. Interventions: rhPTH(1–84) treatment was initiated at a starting dose of 100 μg every other day for 6 years. Due to the availability of new dosages during the 6-year time period of the study, the dose could be and was adjusted for most patients to a daily dosing regimen. Main Outcome Measures: Supplemental calcium and vitamin D requirements, serum and urinary calcium (monthly for 6 mo and then biannually), serum phosphorus, bone turnover markers, and bone mineral density (BMD) biannually. Results: Treatment with rhPTH(1–84) progressively reduced supplemental calcium requirements over 6 years by 53% (P < .0001) and 1,25-dihydroxyvitamin D requirements by 67% (P < .0001). Sixteen subjects (48%) were able to eliminate 1,25-dihydroxyvitamin D supplementation completely. Serum calcium concentration remained stable, and urinary calcium excretion fell. Lumbar spine BMD increased (3.8 ± 1%, P = .004) as did total hip BMD (2.4 ± 1%, P = .02), whereas femoral neck BMD remained stable and the distal one third radius decreased (−4.4 ±1%, P < .0001). Bone turnover markers increased significantly, reaching a 3-fold peak above baseline values at 1 year and subsequently declining but remaining higher than pretreatment values. Hypercalcemia was uncommon (12 episodes over 6 y; 2.5% of all values). Conclusions: Long-term, continuous therapy of hypoparathyroidism for 6 years with rhPTH(1–84) is associated with reductions in supplemental calcium and calcitriol requirements, stable serum calcium concentration, and reduced urinary calcium excretion. The safety profile remains good. These data represent the longest experience with the therapeutic use of PTH for any condition and demonstrate its long-term efficacy and safety in hypoparathyroidism. PMID:27144931

The solubility of olivine in basaltic liquids - An ionic model

NASA Technical Reports Server (NTRS)

Herzberg, C. T.

1979-01-01

A model is presented which enables the temperature at which olivine is in equilibrium with any alkali-depleted basaltic compound to be calculated to within + or - 30 C. It is noted that the error increases substantially when applied to terrestrial basalts which contain several weight percent alkalis. In addition the model predicts and quantifies the reduced activity of SiO4(4-) monomers due to increasing SiO2 concentrations in the melt. It is shown that the coordination of alumina in melts which precipitate olivine only appears to be dominantly octahedral, while titanium acts as a polmerizing agent by interconnecting previously isolated SiO4(4-) monomers. It is concluded that the model is sufficiently sensitive to show that there are small repulsive forces between Mg(2+) and calcium ions which are in association with normative diopside in the melt.

Strong Negative Interference by Calcium Dobesilate in Sarcosine Oxidase Assays for Serum Creatinine Involving the Trinder Reaction

PubMed Central

Guo, Xiuzhi; Hou, Li’an; Cheng, Xinqi; Zhang, Tianjiao; Yu, Songlin; Fang, Huiling; Xia, Liangyu; Qi, Zhihong; Qin, Xuzhen; Zhang, Lin; Liu, Qian; Liu, Li; Chi, Shuling; Hao, Yingying; Qiu, Ling

2015-01-01

Abstract The vasoprotective drug calcium dobesilate is known to interfere with creatinine (Cr) quantifications in sarcosine oxidase enzymatic (SOE) assays. The aim of this study was to investigate this interference in 8 different commercially available assays and to determine its clinical significance. In in vitro experiments, interference was evaluated at 3 Cr levels. For this, Cr was quantified by SOE assays in pooled serum supplemented with calcium dobesilate at final concentrations of 0, 2, 4, 8, 16, 32, and 64 μg/mL. Percent bias was calculated relative to the drug-free specimen. For in vivo analyses, changes in serum concentrations of Cr, cystatin C (CysC; a renal function marker), and calcium dobesilate were monitored in healthy participants of group I before and after oral calcium dobesilate administration. In addition, variations in interference were also examined among different SOE assays using serum obtained from healthy participants of group II. Lastly, Cr levels from the 10 patients treated with calcium dobesilate were measured using 4 SOE assays and liquid chromatography-isotope dilution tandem mass spectrometry (LC-IDMS/MS) for comparison. Our in vitro analyses indicated that the presence of 8 μg/mL calcium dobesilate resulted in a −4.4% to −36.3% reduction in Cr serum concentration compared to drug-free serum for 8 SOE assays examined. In vivo, Cr values decreased relative to the baseline level with increasing drug concentration, with the lowest Cr levels obtained at 2 or 3 hours after drug administration in participants of group I. The observed Cr concentrations for participants in group II were reduced by −28.5% to −3.1% and −60.5% to −11.6% at 0 and 2 hours after administration related to baseline levels. The Cr values of 10 patients measured by Roche, Beckman, Maker, and Merit Choice SOE assays showed an average deviation of −20.0%, −22.4%, −14.2%, and −29.6%, respectively, compared to values obtained by LC-IDMS/MS. These results revealed a clinically significant negative interference with calcium dobesilate in all sarcosine oxidase-based Cr assays, but the degree of interference varied greatly among the assays examined. Thus, extra care should be taken in evaluating Cr quantification obtained by SOE assays in patients undergoing calcium dobesilate therapy. PMID:26061311

Systemic delivery of siRNA by hyaluronan-functionalized calcium phosphate nanoparticles for tumor-targeted therapy

NASA Astrophysics Data System (ADS)

Qiu, Chong; Wei, Wei; Sun, Jing; Zhang, Hai-Tao; Ding, Jing-Song; Wang, Jian-Cheng; Zhang, Qiang

2016-06-01

In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform spherical core-shell morphology with an approximate size of 170 nm and zeta potential of -12 mV. The coating of hydrophilic HA improved the physical stability of nanoparticles over one month due to the strong interactions between phosphonate and calcium. In vitro experiments demonstrated that the negatively charged CaP-AHA/siRNA NPs could effectively deliver EGFR-targeted siRNA into A549 cells through CD44-mediated endocytosis and significantly down-regulate the level of EGFR expression. Also, the internalized CaP-AHA/siRNA NPs exhibited a pH-responsive release of siRNA, indicating that the acidification of lysosomes probably facilitated the disassembling of nanoparticles and the resultant ions sharply increased the inner osmotic pressure and thus expedited the release of siRNA from late lysosomes into the cytoplasm. Furthermore, in vivo tumor therapy demonstrated that high accumulation of CaP-AHA/siEGFR NPs in tumor led to a significant tumor growth inhibition with a specific EGFR gene silencing effect after intravenous administration in nude mice xenografted with A549 tumor, along with a negligible body weight loss. These results suggested that the CaP-AHA/siRNA NPs could be an effective and safe systemic siRNA delivery system for a RNAi-based tumor targeted therapy strategy.In this study, hyaluronan (HA)-functionalized calcium phosphate nanoparticles (CaP-AHA/siRNA NPs) were developed for an injectable and targetable delivery of siRNA, which were prepared by coating the alendronate-hyaluronan graft polymer (AHA) around the surface of calcium phosphate-siRNA co-precipitates. The prepared CaP-AHA/siRNA NPs had a uniform spherical core-shell morphology with an approximate size of 170 nm and zeta potential of -12 mV. The coating of hydrophilic HA improved the physical stability of nanoparticles over one month due to the strong interactions between phosphonate and calcium. In vitro experiments demonstrated that the negatively charged CaP-AHA/siRNA NPs could effectively deliver EGFR-targeted siRNA into A549 cells through CD44-mediated endocytosis and significantly down-regulate the level of EGFR expression. Also, the internalized CaP-AHA/siRNA NPs exhibited a pH-responsive release of siRNA, indicating that the acidification of lysosomes probably facilitated the disassembling of nanoparticles and the resultant ions sharply increased the inner osmotic pressure and thus expedited the release of siRNA from late lysosomes into the cytoplasm. Furthermore, in vivo tumor therapy demonstrated that high accumulation of CaP-AHA/siEGFR NPs in tumor led to a significant tumor growth inhibition with a specific EGFR gene silencing effect after intravenous administration in nude mice xenografted with A549 tumor, along with a negligible body weight loss. These results suggested that the CaP-AHA/siRNA NPs could be an effective and safe systemic siRNA delivery system for a RNAi-based tumor targeted therapy strategy. Electronic supplementary information (ESI) available. See DOI: 10.1039/c6nr04034a

Calcium isotope fractionation in a silicate dominated Cenozoic aquifer system

NASA Astrophysics Data System (ADS)

Li, Junxia; DePaolo, Donald J.; Wang, Yanxin; Xie, Xianjun

2018-04-01

To understand the characteristics of Ca isotope composition and fractionation in silicate-dominated Quaternary aquifer system, hydrochemical and isotope studies (87Sr/86Sr, 13CDIC and 44/40Ca) were conducted on groundwater, sediment and rock samples from the Datong basin, China. Along the groundwater flow path from the basin margin to the center, groundwater hydrochemical type evolves from Ca-HCO3 to Na-HCO3/Na-Cl type, which results from aluminosilicate hydrolysis, vertical mixing, cation exchange between CaX2 and NaX, and calcite/dolomite precipitation. These processes cause the decrease in groundwater Ca concentration and the associated modest fractionation of groundwater Ca isotopes along the flowpath. The groundwater δ44/40Ca value varies from -0.11 to 0.49‰. The elevated δ44/40Ca ratios in shallow groundwater are attributed to vertical mixing involving addition of irrigation water, which had the average δ44/40Ca ratio of 0.595‰. Chemical weathering of silicate minerals and carbonate generates depleted δ44/40Ca signatures in groundwater from Heng Mountain (east area) and Huanghua Uplift (west area), respectively. Along the groundwater flow path from Heng Mountain to central area of east area, cation exchange between CaX2 and NaX on clay mineral results in the enrichment of heavier Ca isotope in groundwater. All groundwater samples are oversaturated with respect to calcite and dolomite. The groundwater environment rich in organic matter promotes the precipitation of carbonate minerals via the biodegradation of organic carbon, thereby further promoting the elevation of groundwater δ44/40Ca ratios.

Osteoblast and osteoclast responses to A/B type carbonate-substituted hydroxyapatite ceramics for bone regeneration.

PubMed

Germaini, Marie-Michèle; Detsch, Rainer; Grünewald, Alina; Magnaudeix, Amandine; Lalloue, Fabrice; Boccaccini, Aldo R; Champion, Eric

2017-06-06

The influence of carbonate substitution (4.4 wt%, mixed A/B type) in hydroxyapatite ceramics for bone remodeling scaffolds was investigated by separately analyzing the response of pre-osteoblasts and osteoclast-like cells. Carbonated hydroxyapatite (CHA) (Ca 9.5 (PO 4 ) 5.5 (CO 3 ) 0.5 (OH)(CO 3 ) 0.25 -CHA), mimicking the chemical composition of natural bone mineral, and pure hydroxyapatite (HA) (Ca 10 (PO 4 ) 6 (OH) 2 -HA) porous ceramics were processed to obtain a similar microstructure and surface physico-chemical properties (grain size, porosity ratio and pore size, surface roughness and zeta potential). The biological behavior was studied using MC3T3-E1 pre-osteoblastic and RAW 264.7 monocyte/macrophage cell lines. Chemical dissolution in the culture media and resorption lacunae produced by osteoclasts occur with both HA and CHA ceramics, but CHA exhibits much higher dissolution and greater bioresorption ability. CHA ceramics promoted a significantly higher level of pre-osteoblast proliferation. Osteoblastic differentiation, assessed by qRT-PCR of RUNX2 and COLIA2, and pre-osteoclastic proliferation and differentiation were not significantly different on CHA or HA ceramics but cell viability and metabolism were significantly greater on CHA ceramics. Thus, the activity of both osteoclast-like and osteoblastic cells was influenced by the carbonate substitution in the apatite structure. Furthermore, CHA showed a particularly interesting balance between biodegradation, by osteoclasts and chemical dissolution, and osteogenesis through osteoblasts' activity, to stimulate bone regeneration. It is hypothesized that this amount of 4.4 wt% carbonate substitution leads to an adapted concentration of calcium in the fluid surrounding the ceramic to stimulate the activity of cells. These results highlight the superior biological behavior of microporous 4.4 wt% A/B CHA ceramics that could beneficially replace the commonly used HA of biphasic calcium phosphates for future applications in bone tissue engineering.

Long-Term Changes in Calcium (Ca) Sources in Base-Poor Forest Ecosystem: Insight from Stable Ca-Isotopes in Tree Rings

NASA Astrophysics Data System (ADS)

Farkas, J.; Dejeant, A.; Orwig, D.; Jacobsen, S. B.

2009-12-01

Calcium (Ca) is an essential nutrient in higher plants and also a major base-cation predicted to be most affected by environmental perturbations such as acid rain deposition and/or excessive biomass harvesting. Therefore, a better understanding of the Ca cycling in terrestrial environment is of primary interest and critical for the sustainable forest management. The aim of this project was to investigate the use of Ca isotopes as a tracer of the forest Ca cycle and its evolution through time. Here we present stable Ca isotope composition (δ44/40Ca and δ44/42Ca) and elemental concentrations of a 260-year record of tree-rings from Red Oak (Quercus rubra). The core sample was collected at an undisturbed old-growth forest site in southern New England (Wachusett Mountain, MA, USA) developed on granitic bedrock. The associated soils (sandy loams) are thus naturally base-poor and sensitive to the loss of Ca due to increased acid rain deposition and/or excessive biological uptake. The δ44/40Ca (NIST) record of decadal tree-ring increments shows a general declining trend from -0.35 to -0.80 ±0.1 per mil (from year 1750 to 2000). Superimposed on this long-term δ44/40Ca trend is a systematic negative excursion with a minimum of -0.95 ±0.1 per mil dated between 1870 and 1950. Overall, the long-term δ44/40Ca record shows statistically significant correlation with Ca/Sr ratios (R2 = 0.87, p < .01) as well as Na/Ca data (R2 = 0.69, p < .01). The fact that δ44/40Ca correlates also with Na/Ca suggest that the observed Ca isotope variations are likely related to changes in soil-Ca sources rather than being a consequence of biological processes within the tree. This is because the sodium budget of trees and forests is primarily controlled by silicate weathering rates derived from the dissolution of Na-rich minerals such as plagioclase and/or K-feldspar. Nevertheless, the role of biological processes on tree-ring δ44/40Ca record will be tested independently via measurements of radiogenic 87Sr/86Sr, as the latter is not discriminated by vital effects. Assuming that the long-term δ44/40Ca and Ca/Sr trends in tree-rings indeed reflect the evolving composition of soil Ca reservoir, the data could be explained by one of the following mechanisms: (i) via selective weathering of apatite (Ca-phosphate) by roots in association with fungus that could provide the source of isotopically light Ca with low Na/Ca ratios (cf. Blum et al. 2002, Nature, 417, 729-731). Alternatively, (ii) the Ca reserves stored in organic matter in the upper soil horizons, as a fairly insoluble Ca-oxalate, were mobilized during times of enhanced acidification (low soil-pH), thus providing the flux of isotopically light Ca to the lower soil nutrient pool. The plausibility of the above scenarios will be tested against new Ca isotope data measured in igneous apatites as well as biological Ca-oxalates.

Does Adding Intravenous Phosphorus to Parenteral Nutrition Has Any Effects on Calcium and Phosphorus Metabolism and Bone Mineral Content in Preterm Neonates?

PubMed

Mazouri, Ali; Khosravi, Nastaran; Bordbar, Arash; Khalesi, Nasrin; Saboute, Maryam; Taherifard, Pegah; Mirzababaee, Marjan; Ebrahimi, Mehran

2017-06-01

The use of parenteral nutritional supplementation of phosphorus may lead to exhibit higher plasma phosphate concentrations and less radiological features in premature neonates susceptible to osteopenia. The present study aimed to assess the beneficial effects of adding intravenous phosphorus to total parenteral nutrition (TPN) on calcium and phosphorus metabolism in preterm neonates by measuring bone mineral content. This open-labeled randomized clinical trial was conducted on premature neonates who were hospitalized at NICU. The neonates were randomly assigned to two groups received TPN with intravenous sodium glycerophosphate or Glycophos (1.5 mmol/kg/day) or TPN without sodium glycerophosphate. At the end of the four weeks of treatment, the presence of osteopenia was examined using DEXA Scan. After completing treatment protocols, the group received TPN with intravenous Glycophos had significantly lower serum alkaline phosphatase (360±60 versus 762±71, P<0.001), as well as higher serum calcium to creatinine ratio (1.6±0.3 versus 0.44±0.13, P<0.001) compared to the control group received TPN without Glycophos. Those who received TPN with intravenous Glycophos experienced more increase in bone mineral density than those in control group (0.13±0.01 versus 0.10±0.02, P<0.001). There was no significant difference in serum calcium and serum vitamin D between the case and control groups. Adding intravenous sodium glycerophosphate to TPN in premature neonates can compensate the lack of bone mineral content and help to prevent osteopenia.

Numerical Study on Recombination Efficiency at 4,4'-Bis(2,2'-diphenylvinyl)-1,1'-spirobiphenyl/Tris(8-quinolinolato)aluminium Interface in Organic Light Emitting Diodes

NASA Astrophysics Data System (ADS)

Hwang, Young Wook; Kim, Kwang Sik; Won, Tae Young

2013-10-01

In this paper, we report our numerical study on the electrical and optical properties of the organic light emitting diodes (OLEDs) devices with n-doped layer, which is inserted for the purpose of reducing the interface barrier height between the cathode and the electron transport layer (ETL). We performed finite element method (FEM) simulation on OLEDs in order to understand the transport behavior of carriers, recombination kinetics, and emission property. Our model includes Poisson's equation, continuity equation to account for behavior of electrons and holes and exciton continuity/transfer equation to account for recombination of carriers. We employ the multilayer structure which consists of indium tin oxide (ITO); 2,2',7,7'-tetrakis(N,N-diphenylamine)-9,9'-spirobi-fluorene (S-TAD); 4,4'-bis(2,2'-diphenylvinyl)-1,1'-spirobiphenyl (S-DPVBi); tris(8-quinolinolato)aluminium (Alq3); calcium (Ca).

In Vitro Evaluation of an Injectable Chitosan Gel for Sustained Local Delivery of BMP-2 for Osteoblastic Differentiation

DTIC Science & Technology

2011-11-01

Res Part B: Appl Biomater 99B: 380–390, 2011. Key Words: injectable gel, chitosan, b- glycerophosphate (b- GP), BMP-2, biocompatibility, release...supplemented with 100 ng/mL BMP-2, 50 l/mL ascorbic acid, and 7 mM b- glycerophosphate for up to 10 days.44 However, W-20-17 cells expressed osteocalcin...mineralization is rapidly initiated and enhanced to form apatite-like calcium mineral depositions. It has been suggested that ascorbic acid, b- glycerophosphate

Lanthanum-silicon-substituted hydroxyapatite: Mechanochemical synthesis and prospects for medical applications

NASA Astrophysics Data System (ADS)

Chaikina, M. V.; Komarova, E. G.; Sharkeev, Yu. P.; Bulina, N. V.; Prosanov, I. Yu.

2016-08-01

The paper presents the results of mechanochemical synthesis of hydroxyapatite (HAP) with simultaneous substitutions of lanthanum (La3+) for calcium ions and silicate ((SiO4)4--group) for the phosphate group with the substituent concentrations in the range 0.2-2.0 mol per HAP mol. The use of Si-substituted HAP as a coating material promotes accelerated osteosynthesis and osteointegration of implants into the bone tissue. The replacement of calcium ions by La3+ in the HAP structure plays an antimicrobial role preventing inflammatory processes. Annealing-induced variations in the lattice parameters of synthesized samples indicate the substituent incorporation into the HAP structure. It is known that complex compounds with lanthanides are used for cancer chemotherapy. In particular, La plays a key role in the course of treatment of injured defects of bone tissue. In addition, La-substituted HAP can be used for filling bone defects and coating implants in postoperational areas affected by bone cancer.

High sodium chloride intake is associated with low bone density in calcium stone-forming patients.

PubMed

Martini, L A; Cuppari, L; Colugnati, F A; Sigulem, D M; Szejnfeld, V L; Schor, N; Heilberg, I P

2000-08-01

Although renal stone disease has been associated with reduced bone mass, the impact of nutrient intake on bone loss is unknown. The present study was undertaken to investigate the influence of nutrient intake on bone density of 85 calcium stone-forming (CSF) patients (47 male and 38 premenopausal females) aged 41+/-11 years (X+/-SD). Bone mineral density (BMD) was measured using dual energy X-ray absorptiometry at the lumbar spine (L2-L4) and femoral neck sites, and low BMD was defined as a T score < -1 (WHO criteria). A 4-day dietary record and a 24-hour urine sample were obtained from each patient for the assessment of nutrient intake and urinary calcium (U(Ca)), sodium (U(Na)), phosphate and creatinine excretion. Forty-eight patients (56%) presented normal BMD and 37 (44%) low BMD. There were no statistical differences regarding age, weight, height, body mass index, protein, calcium and phosphorus intakes between both groups. The mean U(Ca), phosphorus and nitrogen appearance also did not differ between groups. However, there was a higher percentage of hypercalciuria among low vs normal BMD patients (62 vs 33%, p < 0.05). Low BMD patients presented a higher mean sodium chloride (NaCl) intake and excretion (UNa) than normal BMD (14+/-5 vs 12+/-4 g/day and 246+/-85 vs 204+/-68 mEq/day, respectively p < 0.05). The percentage of patients presenting NaCl intake > or = 16 g/day was also higher among low vs normal BMD patients (35 vs 12%, p < 0.05). After adjustment for calcium and protein intakes, age, weight, body mass index, urinary calcium, citrate and uric acid excretion, and duration of stone disease, multiple-regression analysis showed that a high NaCl intake (> or = 16 g/day) was the single variable that was predictive of risk of low bone density in CSF patients (odds ratio = 3.8). These data suggest that reducing salt intake should be recommended for CSF patients presenting hypercalciuria and osteopenia.

Dairy Products, Dietary Calcium and Bone Health: Possibility of Prevention of Osteoporosis in Women: The Polish Experience

PubMed Central

Wadolowska, Lidia; Sobas, Kamila; Szczepanska, Justyna W.; Slowinska, Malgorzata A.; Czlapka-Matyasik, Magdalena; Niedzwiedzka, Ewa

2013-01-01

The objective of the study was to analyze the consumption of dairy products and dietary calcium by women in the context of bone mineral density and to assess opportunities to prevent osteoporosis in a dietary manner. The study was carried out with 712 Polish women. In 170 women aged 32 to 59 bone mineral density (BMD) was measured. The data on the consumption of dairy products and dietary calcium and some other osteoporosis risk factors was collected from 712 women. The average calcium intake from a diet was 507 mg/day. Only 2% of the women met Polish calcium intake recommendations. During adulthood, dairy product consumption or dietary calcium intake did not differ significantly between women with low BMD (below −1 SD) and women with regular BMD (≥−1 SD) (47.4 vs. 44.3 servings/week and 459 vs. 510 mg/day, respectively, p > 0.05). The odds ratios adjusted for age, menstruation and BMI in women with upper BMD tercile in comparison to the reference group (bottom tercile) was 2.73 (95% CI: 1.14, 6.55; p < 0.05) for the daily consumption of dairy products during the pre-school period and 2.40 (95% CI: 1.01, 5.70; p < 0.05) for the daily consumption of dairy products during the school period. Two clusters of women were established. In the S1 cluster, low BMD (below −1 SD) was associated with older age (≥50 years), lack of menstrual cycle. In the S2 cluster, regular BMD (≥−1 SD) was related to younger aged women (<50 years), presence of menstrual cycle, consumption of higher level of dairy products (≥28 servings/week) during adulthood and daily intake of dairy products during childhood and adolescence. The results indicate that good bone health to the large extent depended upon the combined impact of dietary factors and some non-modifiable risk factors of osteoporosis such as age and the presence of menstruation. Consumption of dairy products in childhood and adolescence may improve bone mineral density and reduce the risk of osteoporosis in adult women. PMID:23863825

Maternal consumption of dairy products, calcium, and vitamin D during pregnancy and infantile allergic disorders.

PubMed

Miyake, Yoshihiro; Tanaka, Keiko; Okubo, Hitomi; Sasaki, Satoshi; Arakawa, Masashi

2014-07-01

Epidemiologic evidence of the association between maternal intake of dairy foods, calcium, and vitamin D during pregnancy and childhood allergic disorders is inconclusive. To examine the association between maternal intake of dairy foods, calcium, and vitamin D during pregnancy and childhood allergic disorders in Japanese children aged 23 to 29 months. Study participants were 1,354 mother-child pairs. Maternal intake during pregnancy was assessed with a validated diet history questionnaire administered between April 2007 and March 2008. Wheeze and eczema, defined according to criteria of the International Study of Asthma and Allergies in Childhood, and physician-diagnosed asthma and atopic eczema were assessed via a questionnaire completed by mothers. Higher maternal intake of total dairy products during pregnancy was significantly associated with a reduced risk of infantile eczema (adjusted odds ratio [OR] between extreme quartiles, 0.64; 95% confidence interval [CI], 0.42-0.98). Higher maternal intake of cheese during pregnancy was significantly related to a reduced risk of physician-diagnosed infantile asthma (adjusted OR between extreme quartiles, 0.44; 95% CI, 0.18-0.97). Maternal intake levels of yogurt and calcium during pregnancy were significantly inversely associated with physician-diagnosed infantile atopic eczema (adjusted ORs between extreme quartiles, 0.49 and 0.34; 95% CI, 0.20-1.16 and 0.12-0.84; P for trend = .01 and .03, respectively). Maternal intake of vitamin D during pregnancy was significantly positively associated with infantile eczema (adjusted OR between extreme quartiles, 1.63; 95% CI, 1.07-2.51). Higher maternal intake of total dairy products, cheese, yogurt, and calcium during pregnancy may reduce the risk of infantile eczema, physician-diagnosed asthma, physician-diagnosed atopic eczema, and physician-diagnosed atopic eczema, respectively. Higher maternal intake of vitamin D during pregnancy may increase the risk of infantile eczema. Copyright © 2014 American College of Allergy, Asthma & Immunology. Published by Elsevier Inc. All rights reserved.

Interference of the complex between NCS-1 and Ric8a with phenothiazines regulates synaptic function and is an approach for fragile X syndrome.

PubMed

Mansilla, Alicia; Chaves-Sanjuan, Antonio; Campillo, Nuria E; Semelidou, Ourania; Martínez-González, Loreto; Infantes, Lourdes; González-Rubio, Juana María; Gil, Carmen; Conde, Santiago; Skoulakis, Efthimios M C; Ferrús, Alberto; Martínez, Ana; Sánchez-Barrena, María José

2017-02-07

The protein complex formed by the Ca 2+ sensor neuronal calcium sensor 1 (NCS-1) and the guanine exchange factor protein Ric8a coregulates synapse number and probability of neurotransmitter release, emerging as a potential therapeutic target for diseases affecting synapses, such as fragile X syndrome (FXS), the most common heritable autism disorder. Using crystallographic data and the virtual screening of a chemical library, we identified a set of heterocyclic small molecules as potential inhibitors of the NCS-1/Ric8a interaction. The aminophenothiazine FD44 interferes with NCS-1/Ric8a binding, and it restores normal synapse number and associative learning in a Drosophila FXS model. The synaptic effects elicited by FD44 feeding are consistent with the genetic manipulation of NCS-1. The crystal structure of NCS-1 bound to FD44 and the structure-function studies performed with structurally close analogs explain the FD44 specificity and the mechanism of inhibition, in which the small molecule stabilizes a mobile C-terminal helix inside a hydrophobic crevice of NCS-1 to impede Ric8a interaction. Our study shows the drugability of the NCS-1/Ric8a interface and uncovers a suitable region in NCS-1 for development of additional drugs of potential use on FXS and related synaptic disorders.

Biotransformation of L-tyrosine to Dopamine by a Calcium Alginate Immobilized Mutant Strain of Aspergillus oryzae.

PubMed

Ali, Sikander; Nawaz, Wajeeha

2016-08-01

The present research work is concerned with the biotransformation of L-tyrosine to dopamine (DA) by calcium alginate entrapped conidiospores of a mutant strain of Aspergillus oryzae. Different strains of A. oryzae were isolated from soil. Out of 13 isolated strains, isolate-2 (I-2) was found to be a better DA producer. The wild-type I-2 was chemically improved by treating it with different concentrations of ethyl methyl sulfonate (EMS). Among seven mutant variants, EMS-6 exhibiting maximal DA activity of 43 μg/ml was selected. The strain was further exposed with L-cysteine HCl to make it resistant against diversion and environmental stress. The conidiospores of selected mutant variant A. oryzae EMS-6 strain were entrapped in calcium alginate beads. Different parameters for immobilization were investigated. The activity was further improved from 44 to 62 μg/ml under optimized conditions (1.5 % sodium alginate, 2 ml inoculum, and 2 mm bead size). The best resistant mutant variable exhibited over threefold increase in DA activity (62 μg/ml) than did wild-type I-2 (21 μg/ml) in the reaction mixture. From the results presented in the study, it was observed that high titers of DA activity in vitro could effectively be achieved by the EMS-induced mutagenesis of filamentous fungus culture used.

Homologous human milk supplement for very low birth weight preterm infant feeding

PubMed Central

Grance, Thayana Regina de Souza; Serafin, Paula de Oliveira; Thomaz, Débora Marchetti Chaves; Palhares, Durval Batista

2015-01-01

OBJECTIVE: To develop a homologous human milk supplement for very low-birth weight infant feeding, using an original and simplified methodology, to know the nutritional composition of human milk fortified with this supplement and to evaluate its suitability for feeding these infants. METHODS: For the production and analysis of human milk with the homologous additive, 25 human milk samples of 45mL underwent a lactose removal process, lyophilization and then were diluted in 50mL of human milk. Measurements of lactose, proteins, lipids, energy, sodium, potassium, calcium, phosphorus and osmolality were performed. RESULTS: The composition of the supplemented milk was: lactose 9.22±1.00g/dL; proteins 2.20±0.36g/dL; lipids 2.91±0.57g/dL; calories 71.93±8.69kcal/dL; osmolality 389.6±32.4mOsmol/kgH2O; sodium 2.04±0.45mEq/dL; potassium 1.42±0.15mEq/dL; calcium 43.44±2.98mg/dL; and phosphorus 23.69±1.24mg/dL. CONCLUSIONS: According to the nutritional contents analyzed, except for calcium and phosphorus, human milk with the proposed supplement can meet the nutritional needs of the very low-birth weight preterm infant. PMID:25662564

Plasma chemistry reference values in ostriches.

PubMed

Verstappen, F A L M; Lumeij, J T; Bronneberg, R G G

2002-01-01

Reference values for 18 plasma chemical variables in blue neck ostriches (Struthio camelus australis, n = 60, age 24-36 mo) were established for use in veterinary clinical practice using nonparametric statistics. The following values were established for the percentiles P2.5 and P97.5: sodium 147-157 mmol/L, calcium 2.4-4.8 mmol/L, inorganic phosphate 1.3-2.3 mmol/L, chloride 94-105 mmol/L, glucose 10.3-13.7 mmol/L, urea 0.5-0.8 mmol/L, uric acid 351-649 mumol/L, bile acids 8-33 mumol/L, total protein 39-56 g/L, albumin-globulin ratio 0.45-0.59, osmolality 304-330 mOsm/kg, alkaline phosphate 69-217 IU/L, aspartate aminotransferase 243-418 IU/L, gamma-glutamyltransferase 0-1 IU/L, creatine kinase 1648-4894 IU/L, glutamate dehydrogenase 8-17 IU/L, and lactate dehydrogenase 860-2236 IU/L. The plasma calcium concentration was significantly (P < 0.001; r = 0.74) related to the total protein concentration and an adjustment-formula for calcium was derived: adjusted Ca (mmol/L) = Ca (mmol/L)--0.09 TP (g/L) + 4.4. The influence of blood sample treatment on the plasma potassium concentration as seen in other avian species was demonstrated in a separate experiment, emphasizing the need to separate plasma and cells immediately after collection in avian blood samples.

Cardiovascular diseases and hard drinking waters: implications from a systematic review with meta-analysis of case-control studies.

PubMed

Gianfredi, Vincenza; Bragazzi, Nicola Luigi; Nucci, Daniele; Villarini, Milena; Moretti, Massimo

2017-02-01

This systematic review with meta-analysis, performed according to the Preferred Reporting Items for Systematic Reviews and Meta-analysis (PRISMA) guidelines, aims at evaluating the potential correlation between magnesium and calcium concentration in drinking waters and the risk of cardiovascular diseases (CVD), which impose a considerable burden in high-income countries. Included studies were of the case-control studies type. From an initial list of 643 potentially eligible articles, seven studies were finally retained in the quantitative analysis. Since each one of them assessed different ion concentrations, subjects exposed to the highest concentration versus those exposed to the lowest concentration were compared. By including an overall figure of 44,000 subjects, the result suggests a protective effect of the ions on CVD prevention, with an effect-size (ES) of 0.82 (95% confidence interval CI = [0.70-0.95], p-value = 0.008) for calcium, and ES = 0.75 (95% CI = [0.66-0.86], p-value = 0.000) for magnesium. Hard water consumption seems to be protective against CVD. However, the high heterogeneity (I 2 = 75.24, p-value = 0.001 for calcium; I 2 = 72.96, p-value = 0.0024 for magnesium) and the existence of publication bias limits the robustness and generalizability of these findings. Further high-quality studies are needed to reproduce and confirm these results.

Neuroendocrine control of water content and calcium concentration in the crab Ocypode macrocera (H. Milne-Edwards 1852) (Brachyura, Ocypodae).

PubMed

Bhat, Bilal Ahmad; Elanchezhiyan, C; Ravichandran, S; Allayie, Sartaj Ahmad; Hemalatha, S; Manoharan, V; Rather, Shabir Ahmad; Bhat, Mohmad Ishaq

2012-03-15

The present study is focused to see the effect of crustacean neuroendocrine organs on the water and calcium metabolism which is very much important for the osmoregulatory functions. Since the experiments were carried out to investigate the control of water contents and calcium concentration in the crab, Ocypode macrocera. The animals were collected from the shore of the Bay of the Bengal near Annan Koil one among the biggest landing centers of south east coast of Tamil Nadu, India. The data revealed that water content in the hepatopancreas and thoracic muscle of the control crab were 70.16 and 79.86%, respectively, whereas in the experimental ones, the values were 80.32 and 87.44% after eyestalk removal and 54.52 and 66.98% after eyestalk extract injection. Calcium concentration in both the hepatopancreas and thoracic muscle of the control crab were 2.16 and 2.14 mg g(-1), respectively, whereas in the experimental animals the values were 2.76 and 3.52 mg g(-1) in the eyestalkless crabs and 1.52 and 1.57 mg g(-1) after eyestalk extract injection, respectively. Hence it was observed the % of water content is more in eyestalk less crabs as compared to that of control and injected. The roles of neurosecretory secretions, which control these parameters, were discussed. The ability for Ocypode macrocera to adapt rapidly and maintain homeostasis in a wide range of abnormality supports the fact that Ocypode macrocera are a suitable species for land-based aquaculture in ponds as well as critical condition where rapid fluctuation in salinity can occur.

Vitamin K2 regression aortic calcification induced by warfarin via Gas6/Axl survival pathway in rats.

PubMed

Jiang, Xiaoyu; Tao, Huiren; Qiu, Cuiting; Ma, Xiaolei; Li, Shan; Guo, Xian; Lv, Anlin; Li, Huan

2016-09-05

The aim of this study was to investigate the effect of vitamin K2 on aortic calcification induced by warfarin via Gas6/Axl survival pathway in rats. A calcification model was established by administering 3mg/g warfarin to rats. Rats were divided into 9 groups: control group (0W, 4W, 6W and 12W groups), 4W calcification group, 6W calcification group, 12W calcification group, 6W calcification+6W normal group and 6W calcification+6W vitamin K2 group. Alizarin red S staining measured aortic calcium depositions; alkaline phosphatase activity in serum was measured by a kit; apoptosis was evaluated by TUNEL assay; protein expression levels of Gas6, Axl, phosphorylated Akt (p-Akt), and Bcl-2 were determined by western blotting. The calcium content, calcium depositions, ALP activity and apoptosis were significantly higher in the calcification groups than control group. Gas6, Axl, p-Akt and Bcl-2 expression was lower in the calcification group than control group. 100μg/g vitamin K2 treatment decreased calcium depositions, ALP activity and apoptosis significantly, but increased Gas6, Axl, p-Akt and Bcl-2 expression. 100μg/g vitamin K2 reversed 44% calcification. Pearson correlation analysis showed a positive correlation between formation calcification and apoptosis (R(2)=0.8853, P<0.0001). In conclusion, we established a warfarin-induced calcification model and showed vitamin K2 can inhibit warfarin-induced aortic calcification and apoptosis. The regression of aortic calcification by vitamin K2 involved the Gas6/Axl axis. This data may provide a theoretical basis for future clinical treatments for aortic calcification. Copyright © 2016 Elsevier B.V. All rights reserved.

[Changes of control of disorders of calcium and phosphorus metabolism in Lithuanian hemodialysis centers 1996-2003].

PubMed

Ziginskiene, Edita; Kuzminskis, Vytautas; Bumblyte, Inga Arūne; Kardauskaite, Zydrūne; Uogintaite, Jurgita

2005-01-01

The aim of the study was to evaluate the changes of the rate of disorders of calcium and phosphorus metabolism and their control in patients on hemodialysis (HD) in Lithuania in 1996-2003. Every December during this period we visited all HD centers of Lithuania and collected data on calcium-phosphorus metabolism in HD patients. 51.8% of HD patients in 1999 and 44.6% in 2003 had hyperphosphatemia (>1.8 mmol/l) (p<0.05). The mean phosphate concentration was 1.82+/-0.56 mmol/l in 2003 (p<0.05, comparing with 1.95+/-0.72 mmol/l in 1999 and 1.9+/-0.72 mmol/l in 2001). 7.1% of HD patients had hypocalcemia in 2003 and 7.8% hypercalcemia. Serum parathyroid hormone level was investigated only in 27.3% of HD patients in 1999 and 84.8% in 2003 (p<0.05). Use of alfacalcidol significantly decreased from 77.5% in 1998 to 29.4% in 2003, when the evaluation of serum parathyroid hormone increased (r=-0.911, p=0.03). Serum parathyroid hormone level was not analyzed for 59.8% of patients who used alfacalcidol and 59.4% of them had hyperphosphatemia in 1999 (6.3% and 32.9% in 2003, respectively; p<0.05). 10.7% of these patients had hypercalcemia in 2003. In summary, the correction of disorders of calcium and phosphorus metabolism in HD patients was insufficient but ameliorative. Monitoring of serum parathyroid hormone increased significantly during 1997-2003. The percentage of the precarious use of alfacalcidol decreased significantly when the evaluation of serum parathyroid hormone level became regular.

Incidence and characteristics of kidney stones in patients with horseshoe kidney: A systematic review and meta-analysis

PubMed Central

Pawar, Aditya S.; Thongprayoon, Charat; Cheungpasitporn, Wisit; Sakhuja, Ankit; Mao, Michael A.; Erickson, Stephen B.

2018-01-01

Introduction: The horseshoe kidney (HSK) is the most common type of renal fusion anomaly. The incidence and characteristics of kidney stones in patients with HSK are not well studied. The aim of this meta-analysis was to evaluate the incidence and types of kidney stones in patients with HSK. Methods: A systematic literature search was performed using MEDLINE, EMBASE, and Cochrane Database of Systematic Reviews from the databases' inception through November 2016. Studies assessing the incidence and types of kidney stones in patients with HSK were included. We applied a random-effects model to estimate the incidence of kidney stones. The study protocol was registered with PROSPERO (International Prospective Register of Systematic Reviews; no. CRD42016052037). Results: A total of 14 observational studies with 943 patients (522 adults and 421 pediatric) with HSK were enrolled. The estimated pooled incidence of kidney stones was 36% (95% confidence interval [CI], 15%–59%) in adults with the HSK. Kidney stones were less common in pediatric patients with HSK with an estimated pooled incidence of 3% (95% CI, 2%–5%). The mean age of adult stone formers with HSK was 44.9 ± 6.2 years, and 75% were males. Within reported studies, 89.2% of kidney stones were calcium-based stones (64.2% calcium oxalate [CaOx], 18.8% calcium phosphate [CaP], and 6.2% mixed CaOx/CaP), followed by struvite stones (4.2%), uric acid stones (3.8%), and others (2.8%). Conclusions: Kidney stones are very common in adult patients with HSK with an estimated incidence of 36%. Calcium-based stones are the most prevalent kidney stones in adults with HSKs. These findings may impact the prevention and clinical management of kidney stones in patients with HSK. PMID:29416282

Modifiable Risk Factors for Increased Arterial Stiffness in Outpatient Nephrology

PubMed Central

Elewa, Usama; Fernandez-Fernandez, Beatriz; Alegre, Raquel; Sanchez-Niño, Maria D.; Mahillo-Fernández, Ignacio; Perez-Gomez, Maria Vanessa; El-Fishawy, Hussein; Belal, Dawlat; Ortiz, Alberto

2015-01-01

Arterial stiffness, as measured by pulse wave velocity (PWV), is an independent predictor of cardiovascular events and mortality. Arterial stiffness increases with age. However, modifiable risk factors such as smoking, BP and salt intake also impact on PWV. The finding of modifiable risk factors may lead to the identification of treatable factors, and, thus, is of interest to practicing nephrologist. We have now studied the prevalence and correlates of arterial stiffness, assessed by PWV, in 191 patients from nephrology outpatient clinics in order to identify modifiable risk factors for arterial stiffness that may in the future guide therapeutic decision-making. PWV was above normal levels for age in 85/191 (44.5%) patients. Multivariate analysis showed that advanced age, systolic BP, diabetes mellitus, serum uric acid and calcium polystyrene sulfonate therapy or calcium-containing medication were independent predictors of PWV. A new parameter, Delta above upper limit of normal PWV (Delta PWV) was defined to decrease the weight of age on PWV values. Delta PWV was calculated as (measured PWV) - (upper limit of the age-adjusted PWV values for the general population). Mean±SD Delta PWV was 0.76±1.60 m/sec. In multivariate analysis, systolic blood pressure, active smoking and calcium polystyrene sulfonate therapy remained independent predictors of higher delta PWV, while age, urinary potassium and beta blocker therapy were independent predictors of lower delta PWV. In conclusion, arterial stiffness was frequent in nephrology outpatients. Systolic blood pressure, smoking, serum uric acid, calcium-containing medications, potassium metabolism and non-use of beta blockers are modifiable factors associated with increased arterial stiffness in Nephrology outpatients. PMID:25880081

Calcium Isotopic Systematics of Peridotite Xenoliths from eastern North China Craton: Implications for Melt-rock Interaction

NASA Astrophysics Data System (ADS)

Zhang, Z.; Zhao, X.; Huang, S.; Xiao, Y.; Li, X.

2017-12-01

In order to better constrain and understand the Ca isotopic variations in the mantle, we report high-precision Ca isotopic data of orthopyroxene (Opx) and clinopyroxene (Cpx) for a set of peridotitic xenoliths from ChangLe, eastern North China craton (NCC). These xenoliths range from lherzolites, Cpx-rich lherzolites to wehrlites, and are variably metasomatised. Lherzolites (Fo≈91) are fertile in mineral composition, and have spoon-shaped to slightly LREE-enriched rare earth element (REE) patterns. They may represent fragments of newly accreted lithospheric mantle that makes up parts of the Late Mesozoic-Cenozoic lithosphere beneath the eastern NCC. Cpx-rich lherzolites and wehrlites formed by reaction of refractory residual peridotites with evolved, Fe-rich silicate melts at high melt/rock ratios, as evidenced by partial to complete replacement of Opx with Cpx, relatively lower Fo contents of Ol (<88) than that from the lherzolites and convex-upward trace element patterns. Our results show that there are large δ44/40Ca variations (1‰) in these peridotitic xenoliths. Lherzolites have δ44/40Ca similar to typical upper mantle value(1.05 ± 0.04). Specifically, lherzolites orthopyroxenes have δ44/40Ca ranging from 1.04 to 1.79, and lherzolites clinopyroxenes have δ44/40Ca from 0.80 to 1.04. In contrast, δ44/40Ca in Cpx-rich lherzolites and wehrlites tend to have lower values reltaive to those of lherzolites. Their clinopyroxenes have δ44/40Ca ranging from 0.42 to 0.92, and their orthopyroxenes have δ44/40Ca ranging from 0.80 to 1.04. Collectively, we identify a positive correlation between clinopyroxene δ44/40Ca and Mg#. Model calculations show that kinetic isotopic fractionation caused by diffusion, probably during mantle melt-rock interaction, is responsible for the positive correlation between clinopyroxene δ44/40Ca and Mg# in these NCC peridotites. Our study shows that melt-rock interaction plays an important role in producing Ca isotopic heterogeneity of the subcontinental mantle.

Daily intake of vitamin D- or calcium-vitamin D-fortified Persian yogurt drink (doogh) attenuates diabetes-induced oxidative stress: evidence for antioxidative properties of vitamin D.

PubMed

Nikooyeh, B; Neyestani, T R; Tayebinejad, N; Alavi-Majd, H; Shariatzadeh, N; Kalayi, A; Zahedirad, M; Heravifard, S; Salekzamani, S

2014-04-01

Both poor vitamin D status and oxidative stress (OS) have been independently associated with late diabetic complications, including cardiovascular disease (CVD). The present study aimed to examine the effect of daily intake of vitamin D alone or in combination with calcium as a fortified Persian yogurt drink (doogh) on OS over 12 weeks. Ninety patients with type 2 diabetes aged 30-50 years from both sexes were randomly allocated to one of the three groups to receive two 250-mL bottles of doogh a day, which was either plain (PD; containing 150 mg per 250 mL of calcium and no detectable vitamin D), vitamin D-fortified (DD; containing 150 mg of calcium + 500 IU vitamin D per 250 mL) or calcium-vitamin D-fortified (CDD; 250 mg od calcium + 500 IU vitamin D per 250 mL). Although mean (SD) serum concentrations of protein carbonyl significantly decreased in both DD and CDD groups [-2.07 (4.39) nm, P = 0.015 and -4.4 (7.64) nm, P = 0.003, respectively], the change in PD group was not significant [-0.54 (6.96) nm, P = 0.674]. A similar pattern was observed for cardiac myeloperoxidase [PD: -19.4 (75.9) μg L(-1) , P = 0.173; DD: -21.8 (54.2) μg L(-1) , P = 0.035, CDD: -48.5 (76.9) μg L(-1) , P = 0.002]. Superoxide dismutase increased significantly only in DD and CDD [56.9 (74.0) U L(-1) , P < 0.001 and 51.6 (119.9) U L(-1) , P = 0.025, respectively]. Changes of serum advanced glycation end-products showed a significant between-group difference among PD, DD and CDD [239.4 (388.4) U L(-1) , -58.1 (147.6) U L(-1) and -143.7 (475.9) U L(-1)  × 10(3) , respectively, P = 0.003], which remained significant after controlling for changes of fasting serum glucose (P = 0.013) and glycated haemoglobin (P = 0.015). The findings of the present study demonstrated an OS attenuating effect of vitamin D. However, extra calcium did not convey additional benefit. © 2013 The British Dietetic Association Ltd.

Mechanochemical Synthesis of Hydroxyapatite and Its Modifications: Composition, Structure, and Properties

NASA Astrophysics Data System (ADS)

Chaikina, M. V.; Bulina, N. V.; Ishchenko, A. V.; Prosanov, I. Yu.

2014-02-01

The mechanochemical method is used to synthesize samples of hydroxyapatite (HA) with substitution of the phosphate ion by silicate and zirconate ions, and substitution of calcium ions by copper ions. In the process of mechanochemical synthesis, carbonate ions and water molecules are incorporated into the structure of HA due to interaction of components of the reaction mixture with air. Intrusion of carbonate into the structure of HA is a competing process with modification of apatite by silicate and zirconate anions; therefore, the composition of the product during synthesis differs from the prescribed one. After annealing of the samples, the composition of the anion-modified HA can be described by the formula Са10(РО4)6- х (АО4) х (ОН)2- х , where (АО4)4- is the modifying anion. Substitution of calcium by copper ions localized at the Са1 position has been detected. Silver ions are not incorporated into the structure of HA, but are distributed in the apatite matrix in the form of nanocrystals of metallic silver.

Ciprofloxacin HCl-loaded calcium carbonate nanoparticles: preparation, solid state characterization, and evaluation of antimicrobial effect against Staphylococcus aureus.

PubMed

Maleki Dizaj, Solmaz; Lotfipour, Farzaneh; Barzegar-Jalali, Mohammad; Zarrintan, Mohammad-Hossein; Adibkia, Khosro

2017-05-01

Ciprofloxacin HCl-loaded calcium carbonate (CaCO 3 ) nanoparticles were prepared via a w/o microemulsion method and characterized by dynamic light scattering, scanning electron microscopy, X-ray powder diffraction (XRPD) analysis, differential scanning calorimetry (DSC), and Fourier transform infrared spectroscopy (FTIR). The in vitro drug release profiles as well as antimicrobial effect against Staphylococcus aureus (S. aureus) were also evaluated. The antibacterial effect was studied using serial dilution technique to determine the minimum inhibitory concentration (MIC) of the nanoparticles and was confirmed by streak cultures. The mean particle size, drug loading and entrapment efficiency were calculated to be 116.09 nm, 20.49% and 44.05%, respectively. PXRD and FTIR studies confirmed that both vaterite and calcite polymorphs of CaCO 3 were formed during the preparation process. In vitro release profiles of the nanoparticles showed slow release pattern for 12 h. The drug-loaded nanoparticles showed similar MICs against S. aureus compared to untreated drug. However, a preserved antimicrobial effect was observed for drug-loaded nanoparticles compared to untreated drug after 2 days of incubation.

Precision Isotope Shift Measurements in Calcium Ions Using Quantum Logic Detection Schemes.

PubMed

Gebert, Florian; Wan, Yong; Wolf, Fabian; Angstmann, Christopher N; Berengut, Julian C; Schmidt, Piet O

2015-07-31

We demonstrate an efficient high-precision optical spectroscopy technique for single trapped ions with nonclosed transitions. In a double-shelving technique, the absorption of a single photon is first amplified to several phonons of a normal motional mode shared with a cotrapped cooling ion of a different species, before being further amplified to thousands of fluorescence photons emitted by the cooling ion using the standard electron shelving technique. We employ this extension of the photon recoil spectroscopy technique to perform the first high precision absolute frequency measurement of the 2D(3/2)→2P(1/2) transition in calcium, resulting in a transition frequency of f=346 000 234 867(96)  kHz. Furthermore, we determine the isotope shift of this transition and the 2S(1/2)→2P(1/2) transition for 42Ca+, 44Ca+, and 48Ca+ ions relative to 40Ca+ with an accuracy below 100 kHz. Improved field and mass shift constants of these transitions as well as changes in mean square nuclear charge radii are extracted from this high resolution data.

Inhibition of myosin light-chain phosphorylation inverts the birefringence response of porcine airway smooth muscle

PubMed Central

Smolensky, Alexander V; Gilbert, Susan H; Harger-Allen, Margaret; Ford, Lincoln E

2007-01-01

Muscle birefringence, caused mainly by parallel thick filaments, increases in smooth muscle during stimulation, signalling thick filament formation upon activation. The reverse occurs in skeletal muscle, where a decrease in birefringence has been correlated with crossbridge movement away from the thick filaments. When force generation by trachealis muscle was inhibited with wortmannin, which inhibits myosin light-chain phosphorylation and thick-filament formation, but not the calcium increase caused by stimulation, the birefringence response inverted, suggesting crossbridge movement similar to that of skeletal muscle. Resistance to quick stretches was much greater in stimulated muscle than in unstimulated muscle before wortmannin treatment and no different in stimulated and unstimulated muscle after force inhibition by wortmannin. Before wortmannin treatment, stimulation reduced thick-filament cross-sectional areas in electron micrographs by 44%. After force inhibition by wortmannin, filament areas were not significantly different in stimulated and unstimulated muscle and not significantly different from those of relaxed muscle without wortmannin treatment. These results suggest that myofibrillar-space calcium causes crossbridges to move away from the thick filaments without firmly attaching to thin filaments. PMID:17095560

Modulation by clamping: Kv4 and KChIP interactions.

PubMed

Wang, Kewei

2008-10-01

The rapidly inactivating (A-type) potassium channels regulate membrane excitability that defines the fundamental mechanism of neuronal functions such as pain signaling. Cytosolic Kv channel-interacting proteins KChIPs that belong to neuronal calcium sensor (NCS) family of calcium binding EF-hand proteins co-assemble with Kv4 (Shal) alpha subunits to form a native complex that encodes major components of neuronal somatodendritic A-type K+ current, I(SA), in neurons and transient outward current, I(TO), in cardiac myocytes. The specific binding of auxiliary KChIPs to the Kv4 N-terminus results in modulation of gating properties, surface expression and subunit assembly of Kv4 channels. Here, I attempt to emphasize the interaction between KChIPs and Kv4 based on recent progress made in understanding the structure complex in which a single KChIP1 molecule laterally clamps two neighboring Kv4.3 N-termini in a 4:4 manner. Greater insights into molecular mechanism between KChIPs and Kv4 interaction may provide therapeutic potentials of designing compounds aimed at disrupting the protein-protein interaction for treatment of membrane excitability-related disorders.

Ent-7α-acetoxytrachyloban-18-oic acid and ent-7α-hydroxytrachyloban-18-oic acid from Xylopia langsdorfiana A. St-Hil. & Tul. modulate K(+) and Ca(2+) channels to reduce cytosolic calcium concentration on guinea pig ileum.

PubMed

Santos, Rosimeire F; Martins, Italo R R; Travassos, Rafael A; Tavares, Josean F; Silva, Marcelo S; Paredes-Gamero, Edgar J; Ferreira, Alice T; Nouailhetas, Viviane L A; Aboulafia, Jeannine; Rigoni, Vera L S; da Silva, Bagnólia A

2012-03-05

In this study we investigated the mechanism underlying the spasmolytic action of ent-7α-acetoxytrachyloban-18-oic acid (trachylobane-360) and ent-7α-hydroxytrachyloban-18-oic acid (trachylobane-318), diterpenes obtained from Xylopia langsdorfiana, on guinea pig ileum. Both compounds inhibited histamine-induced cumulative contractions (slope=3.5±0.9 and 4.4±0.7) that suggests a noncompetitive antagonism to histaminergic receptors. CaCl(2)-induced contractions were nonparallelly and concentration-dependently reduced by both diterpenes, indicating blockade of calcium influx through voltage-dependent calcium channels (Ca(v)). The Ca(v) participation was confirmed since both trachylobanes equipotently relaxed ileum pre-contracted with S-(-)-Bay K8644 (EC(50)=3.5±0.7×10-(5) and 1.1±0.2×10-(5)M) and KCl (EC(50)=5.5±0.3×10-(5) and 1.4±0.2×10-(5)M). K(+) channels participation was confirmed since diterpene-induced relaxation curves were significantly shifted to right in the presence of 5mM tetraethylammonium (TEA(+)) (EC(50)=0.5±0.04×10-(4) and 2.0±0.5×10-(5)M). ATP-sensitive K(+) channel (K(ATP)), voltage activated K(+) channels (K(V)), small conductance calcium-activated K(+) channels (SK(Ca)) or big conductance calcium-activated K(+) channels (BK(Ca)) did not seem to participate of trachylobane-360 spasmolytic action. However trachylobane-318 modulated positively K(ATP), K(V) and SK(Ca) (EC(50)=1.1±0.3×10-(5), 0.7±0.2×10-(5) and 0.7±0.2×10-(5)M), but not BK(Ca). A fluorescence analysis technique confirmed the decrease of cytosolic calcium concentration ([Ca(2+)](c)) induced by both trachylobanes in ileal myocytes. In conclusion, trachylobane-360 and trachylobane-318 induced spasmolytic activity by K(+) channel positive modulation and Ca(2+) channel blockade, which results in [Ca(2+)](c) reduction at cellular level leading to smooth muscle relaxation. Copyright © 2011. Published by Elsevier B.V.

Calcium isotope signature: new proxy for net change in bone volume for chronic kidney disease and diabetic rats.

PubMed

Tanaka, Yu-Ki; Yajima, Nobuyuki; Higuchi, Yusuke; Yamato, Hideyuki; Hirata, Takafumi

2017-12-01

Herein, we measure the Ca isotope ratios ( 44 Ca/ 42 Ca and 43 Ca/ 42 Ca) in serum and bone samples collected from rats with chronic kidney disease (CKD) or diabetes mellitus (DM). For the serum samples, the isotope ratios are lower for the CKD (δ 44 Ca/ 42 Ca serum = 0.16 ± 0.11‰; 2SD, n = 6) and the DM (δ 44 Ca/ 42 Ca serum = -0.11 ± 0.25‰; 2SD, n = 7) rats than that for the control rats (δ 44 Ca/ 42 Ca serum = 0.25 ± 0.04‰; 2SD, n = 7). Bone samples from two distinct positions of 20 rats in total, namely, the center and proximal parts of the tibial diaphysis, are subject to Ca isotope analysis. The resulting δ 44 Ca/ 42 Ca values for the bone of the proximal part are about 0.3‰ lower than that for the serum samples from the same rats. The larger isotope fractionations between the serum and bone are consistent with previously reported data for vertebrate animals (e.g., Skulan and DePaolo, 1999), which suggests the preferential incorporation of lighter Ca isotopes through bone formation. For the bones from the control and CKD rats, there were no differences in the δ 44 Ca/ 42 Ca values between the positions of the bone. In contrast, the δ 44 Ca/ 42 Ca values of the bone for the DM rats were different between the positions of the bone. Due to the lower bone turnover rate for the DM rats, the δ 44 Ca/ 42 Ca for the middle of the diaphysis can reflect the Ca isotopes in the bone formed prior to the progression of DM states. Thus, the resulting δ 44 Ca/ 42 Ca values show a clear correlation with bone mineral density (BMD). This can be due to the release of isotopically lighter Ca from the bone to the serum. In the present study, our data demonstrate that the δ 44 Ca/ 42 Ca value for serum can be used as a new biomarker for evaluating changes in bone turnover rate, followed by changes in bone volume.

Static Magnetic Field Exposure Reproduces Cellular Effects of the Parkinson's Disease Drug Candidate ZM241385

PubMed Central

Wang, Zhiyun; Che, Pao-Lin; Du, Jian; Ha, Barbara; Yarema, Kevin J.

2010-01-01

Background This study was inspired by coalescing evidence that magnetic therapy may be a viable treatment option for certain diseases. This premise is based on the ability of moderate strength fields (i.e., 0.1 to 1 Tesla) to alter the biophysical properties of lipid bilayers and in turn modulate cellular signaling pathways. In particular, previous results from our laboratory (Wang et al., BMC Genomics, 10, 356 (2009)) established that moderate strength static magnetic field (SMF) exposure altered cellular endpoints associated with neuronal function and differentiation. Building on this background, the current paper investigated SMF by focusing on the adenosine A2A receptor (A2AR) in the PC12 rat adrenal pheochromocytoma cell line that displays metabolic features of Parkinson's disease (PD). Methodology and Principal Findings SMF reproduced several responses elicited by ZM241385, a selective A2AR antagonist, in PC12 cells including altered calcium flux, increased ATP levels, reduced cAMP levels, reduced nitric oxide production, reduced p44/42 MAPK phosphorylation, inhibited proliferation, and reduced iron uptake. SMF also counteracted several PD-relevant endpoints exacerbated by A2AR agonist CGS21680 in a manner similar to ZM241385; these include reduction of increased expression of A2AR, reversal of altered calcium efflux, dampening of increased adenosine production, reduction of enhanced proliferation and associated p44/42 MAPK phosphorylation, and inhibition of neurite outgrowth. Conclusions and Significance When measured against multiple endpoints, SMF elicited qualitatively similar responses as ZM241385, a PD drug candidate. Provided that the in vitro results presented in this paper apply in vivo, SMF holds promise as an intriguing non-invasive approach to treat PD and potentially other neurological disorders. PMID:21079735

Structural basis for the metal-selective activation of the manganese transport regulator of Bacillus subtilis.

PubMed

Kliegman, Joseph I; Griner, Sarah L; Helmann, John D; Brennan, Richard G; Glasfeld, Arthur

2006-03-21

The manganese transport regulator (MntR) of Bacillus subtilis is activated by Mn(2+) to repress transcription of genes encoding transporters involved in the uptake of manganese. MntR is also strongly activated by cadmium, both in vivo and in vitro, but it is poorly activated by other metal cations, including calcium and zinc. The previously published MntR.Mn(2+) structure revealed a binuclear complex of manganese ions with a metal-metal separation of 3.3 A (herein designated the AB conformer). Analysis of four additional crystal forms of MntR.Mn(2+) reveals that the AB conformer is only observed in monoclinic crystals at 100 K, suggesting that this conformation may be stabilized by crystal packing forces. In contrast, monoclinic crystals analyzed at room temperature (at either pH 6.5 or pH 8.5), and a second hexagonal crystal form (analyzed at 100 K), all reveal the shift of one manganese ion by 2.5 A, thereby leading to a newly identified conformation (the AC conformer) with an internuclear distance of 4.4 A. Significantly, the cadmium and calcium complexes of MntR also contain binuclear complexes with a 4.4 A internuclear separation. In contrast, the zinc complex of MntR contains only one metal ion per subunit, in the A site. Isothermal titration calorimetry confirms the stoichiometry of Mn(2+), Cd(2+), and Zn(2+) binding to MntR. We propose that the specificity of MntR activation is tied to productive binding of metal ions at two sites; the A site appears to act as a selectivity filter, determining whether the B or C site will be occupied and thereby fully activate MntR.

Effects of RAAS Blockers on Atrial Fibrillation Prophylaxis: An Updated Systematic Review and Meta-Analysis of Randomized Controlled Trials.

PubMed

Chaugai, Sandip; Meng, Wen Yeng; Ali Sepehry, Amir

2016-07-01

Impact of atrial fibrillation on clinical outcomes is well recognized, and application of renin-angiotensin-aldosterone system (RAAS) blockers for the prevention of atrial fibrillation (AF) is a theoretically appealing concept. However, clinical trials have yielded inconsistent results. A pooled study of 26 randomized controlled trials (RCTs) assessing the efficacy of RAAS blockers on AF prophylaxis was performed. A total of 28 reports from 26 randomized controlled trials enrolled 165 387 patients, with an overall 24% reduction in the incidence of AF (odds ratio [OR]: 0.76, 95% confidence interval [CI]: 0.68-0.85], P = .000). Forty-nine percent reduction in the incidence of AF (OR: 0.51, 95% CI: 0.30-0.85, P = .010) in systolic heart failure was observed, whereas no significant effect was observed in patients with diastolic heart failure, postmyocardial infarction, and high cardiovascular disease risk. There was a 19% (OR: 0.81, 95% CI: 0.67-1.00, P = .037) reduction in new-onset and 54% (OR: 0.46, 95% CI: 0.33-0.62, P = .000) reduction in recurrent AF in hypertensive patients with 39% (OR: 0.61, 95% CI: 0.44-0.84, P = .003) risk reduction against calcium blockers and 41% (OR: 0.59, 95% CI: 0.44-0.80, P = .001) risk reduction against β blockers. Angiotensin-receptor blocker appeared marginally superior to angiotensin-converting enzyme inhibitor in primary and secondary prevention. This study suggests that RAAS blockade effectively suppresses AF in systolic heart failure, and hypertensives derive greater benefit against new-onset and recurrent AF compared to β blockers, calcium channel blockers, and diuretics. © The Author(s) 2016.

Understanding the Calcium Isotope and Trace Metal Composition of Elasmobranch Teeth: Implications for Recreating the δ44/40Ca of Seawater

NASA Astrophysics Data System (ADS)

Akhtar, A.; Higgins, J. A.

2017-12-01

Non-traditional stable isotopes in marine fossils have the potential to act as archives of paleo-seawater chemistry, biological evolution, and ancient ecosystems. In particular, bioapatite in elasmobranch enamel has been shown to be a robust proxy for environmental, geochemical and ecological reconstructions through Earth history due to its temporal range (from Devonian to present day) and resistance to diagenetic alteration. Moreover, frequent replacement rates of teeth in individuals, and high species level diversity and global distribution ensure a sample suite that encompasses a wide range of geographies and ecosystems. Here we present δ44/40Ca, δ87/86Sr and trace element (e.g. Sr/Ca, Mg/Ca) data from a suite of 300 teeth spanning the Cretaceous to present day and representing primary, secondary and tertiary piscivores. Modern teeth analyzed as part of this study have an average δ44/40Ca value of -2.07±0.48‰ (2s, n = 80) and Sr/Ca ratio of 2.30±0.24 mmol/mol (2s, n = 40), both offset from present day seawater (0 permil and 8.6 mmol/mol, respectively) due to a combination of inorganic (e.g. mineral precipitation) and biological (e.g. ionic regulation) effects. The total range in δ44/40Ca values in modern teeth is 1.19‰, the same order as that expected for variations in the δ44/40Ca value of ancient seawater. Using results from synthetic apatite synthesis experiments, mathematical modeling, and measurements of shark soft-tissue (e.g. blood and flesh), we explore sources of Ca isotope variability in shark teeth and evaluate their potential as archives of ancient seawater chemistry.

Estimation of bone mineral content using gamma camera: A real possibility

DOE Office of Scientific and Technical Information (OSTI.GOV)

Levy, L.M.; Hoory, S.; Bandyopadhyay, D.

1985-05-01

Osteopenia and Osteoporosis are the diseases related to loss of bone minerals. At present, dual photon absorptiometry using a dedicated specially built scanner along with a very high source of Gd-153 is being used as a diagnostic tool for the early detection of bone loss. The present study was undertaken to explore the possibility that gamma cameras which are widely available in all Nuclear Medicine departments could be used successfully to evaluate bone mineral content. A Siemens LFOV gamma camera equipped with a converging collimator was used for this purpose. A fixed source (100 mCi) of Gd-153 was placed atmore » the focal point of the collimator. A series of calcium chloride solutions of varying concentrations in plastic vials were placed near the center of the collimator and imaged both in air and water. Both 44 Kev and 100 Kev images were digitized in 128 x 128 matrices and processed in a CD and A Delta system attached to a VAX 11-750 computer. Uniformity corrections for each field of view were applied and the attenuation coefficients of calcium chloride for both peaks of Gd-153 were evaluated. In addition, due to the high count rate, corrections for the dead time losses were also found to be essential. An excellent concordance between the estimated Calcium contents and that actually present were obtained by this technic. In conclusion, use of gamma camera for the routine evaluation of Osteoporosis appears to be highly promising and worth pursuing.« less

Basolateral K+ channel involvement in forskolin-activated chloride secretion in human colon

PubMed Central

McNamara, Brian; Winter, Desmond C; Cuffe, John E; O'Sullivan, Gerald C; Harvey, Brian J

1999-01-01

In this study we investigated the role of basolateral potassium transport in maintaining cAMP-activated chloride secretion in human colonic epithelium. Ion transport was quantified in isolated human colonic epithelium using the short-circuit current technique. Basolateral potassium transport was studied using nystatin permeabilization. Intracellular calcium measurements were obtained from isolated human colonic crypts using fura-2 spectrofluorescence imaging. In intact isolated colonic strips, forskolin and prostaglandin E2 (PGE2) activated an inward transmembrane current (ISC) consistent with anion secretion (for forskolin ΔISC = 63.8 ± 6.2 μA cm−2, n = 6; for PGE2 ΔISC = 34.3 ± 5.2 μA cm−2, n = 6). This current was inhibited in chloride-free Krebs solution or by inhibiting basolateral chloride uptake with bumetanide and 4,4′-diisothiocyanatostilbene-2,2′-disulfonic acid (DIDS). The forskolin- and PGE2-induced chloride secretion was inhibited by basolateral exposure to barium (5 mM), tetrapentylammonium (10 μM) and tetraethylammonium (10 mM). The transepithelial current produced under an apical to serosal K+ gradient in nystatin-perforated colon is generated at the basolateral membrane by K+ transport. Forskolin failed to activate this current under conditions of high or low calcium and failed to increase the levels of intracellular calcium in isolated crypts In conclusion, we propose that potassium recycling through basolateral K+ channels is essential for cAMP-activated chloride secretion. PMID:10432355

Relation of aortic valve calcium to chronic kidney disease (from the Chronic Renal Insufficiency Cohort Study).

PubMed

Guerraty, Marie A; Chai, Boyang; Hsu, Jesse Y; Ojo, Akinlolu O; Gao, Yanlin; Yang, Wei; Keane, Martin G; Budoff, Matthew J; Mohler, Emile R

2015-05-01

Although subjects with chronic kidney disease (CKD) are at markedly increased risk for cardiovascular mortality, the relation between CKD and aortic valve calcification has not been fully elucidated. Also, few data are available on the relation of aortic valve calcification and earlier stages of CKD. We sought to assess the relation of aortic valve calcium (AVC) with estimated glomerular filtration rate (eGFR), traditional and novel cardiovascular risk factors, and markers of bone metabolism in the Chronic Renal Insufficiency Cohort (CRIC) Study. All patients who underwent aortic valve scanning in the CRIC study were included. The relation between AVC and eGFR, traditional and novel cardiovascular risk factors, and markers of calcium metabolism were analyzed using both unadjusted and adjusted regression models. A total of 1,964 CRIC participants underwent computed tomography for AVC quantification. Decreased renal function was independently associated with increased levels of AVC (eGFR 47.11, 44.17, and 39 ml/min/1.73 m2, respectively, p<0.001). This association persisted after adjusting for traditional, but not novel, AVC risk factors. Adjusted regression models identified several traditional and novel risk factors for AVC in patients with CKD. There was a difference in AVC risk factors between black and nonblack patients. In conclusion, our study shows that eGFR is associated in a dose-dependent manner with AVC in patients with CKD, and this association is independent of traditional cardiovascular risk factors. Copyright © 2015 Elsevier Inc. All rights reserved.

Effects of hyperthermia on enzymes and electrolytes in blood and cerebrospinal fluid in dogs

NASA Astrophysics Data System (ADS)

Deswal, K.; Chohan, I. S.

1981-09-01

The effects of exposure to various degrees of heat stress on serum glutamate—oxaloacetate transaminase (SGOT), serum glutamate-pyruvate transaminase (SGPT), alkaline phosphatase (ALK-P-ase), calcium and chlorides have been studied on 75 dogs. Rectal temperature (Tre) was recorded before and after exposure to heat stress. These dogs were divided into 5 groups, according to the Tre level attained after exposure to heat stress. Rectal temperature was raised from normal to 39.45±0.47‡C in the first group, to 40.93±0.17‡C in the second group, to 41.87±0.22‡C in the third group, to 42.90 ± 0.21‡C in the fourth group and to 43.93±0.19‡C in the fifth group. The concentration of enzymes SGOT, SGPT and ALK-P-ase in blood and cerebrospinal fluid (CSF) increased significantly with hyperthermia. Calcium and chlorides concentrations in blood and in CSF tended to increase in hyperthermia. The integrity of the blood brain barrier for these enzymes and calcium is maintained under mild hyperthermia but it breaks down partially under influence of more severe hyperthermia. Core temperature above 41‡C results in damage to tissues and consequential rise of plasma enzymes. This degree of hyperthermia also seems to mark the beginning of injury to blood brain barrier. Critical core temperature tolerated by 50% of animals was 44‡C.

High-precision measurement of variations in calcium isotope ratios in urine by multiple collector inductively coupled plasma mass spectrometry

USGS Publications Warehouse

Morgan, J.L.L.; Gordon, G.W.; Arrua, R.C.; Skulan, J.L.; Anbar, A.D.; Bullen, T.D.

2011-01-01

We describe a new chemical separation method to isolate Ca from other matrix elements in biological samples, developed with the long-term goal of making high-precision measurement of natural stable Ca isotope variations a clinically applicable tool to assess bone mineral balance. A new two-column procedure utilizing HBr achieves the purity required to accurately and precisely measure two Ca isotope ratios (44Ca/42Ca and 44Ca/43Ca) on a Neptune multiple collector inductively coupled plasma mass spectrometer (MC-ICPMS) in urine. Purification requirements for Sr, Ti, and K (Ca/Sr > 10000; Ca/Ti > 10000000; and Ca/K > 10) were determined by addition of these elements to Ca standards of known isotopic composition. Accuracy was determined by (1) comparing Ca isotope results for samples and standards to published data obtained using thermal ionization mass spectrometry (TIMS), (2) adding a Ca standard of known isotopic composition to a urine sample purified of Ca, and (3) analyzing mixtures of urine samples and standards in varying proportions. The accuracy and precision of δ44/42Ca measurements of purified samples containing 25 μg of Ca can be determined with typical errors less than ±0.2‰ (2σ).

Calcium Isotopic Composition of Bulk Silicate Earth

NASA Astrophysics Data System (ADS)

Kang, J.; Ionov, D. A.; Liu, F.; Zhang, C.; Zhang, Z.; Huang, F.

2016-12-01

Ca isotopes are used to study the accretion history of the Earth and terrestrial planets, but, Ca isotopic composition of the Bulk Silicate Earth (BSE) remains poorly constrained [1]. To better understand the Ca isotopic composition of BSE, we analyzed 22 well studied peridotite xenoliths from Tariat (Mongolia), Vitim (southern Siberia) and Udachnaya (Siberian Craton). These samples include both fertile and highly depleted garnet and spinel peridotites that show no or only minor post-melting metasomatism or alteration. Ca isotope measurements were done on a Triton-TIMS using double spike method at the Guangzhou Institute of Geochemistry, CAS. The data are reported as δ44/40Ca (relative to NIST SRM 915a). Results for geostandards are consistent with those from other laboratories. 2 standard deviations of SRM 915a analyses are 0.13‰ (n=48). δ44/40Ca of both and fertile and refractory peridotites range from 0.79 to 1.07‰ producing an average of 0.93±0.12‰ (2SD). This value defines the Ca isotopic composition of the BSE, which is consistent with the average δ44/40Ca of oceanic basalts ( 0.90‰)[2,3]. [1] Huang et al (2010) EPSL 292; [2] Valdes et al (2014) EPSL 394; [3]DePaolo (2004) RMG 55.

Calcium and phosphorus regulatory hormones and risk of incident symptomatic kidney stones.

PubMed

Taylor, Eric N; Hoofnagle, Andrew N; Curhan, Gary C

2015-04-07

Calcium and phosphorus regulatory hormones may contribute to the pathogenesis of calcium nephrolithiasis. However, there has been no prospective study to date of plasma hormone levels and risk of kidney stones. This study aimed to examine independent associations between plasma levels of 1,25-dihydroxyvitamin D (1,25[OH]2D), 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, fibroblast growth factor 23 (FGF23), parathyroid hormone, calcium, phosphate, and creatinine and the subsequent risk of incident kidney stones. This study was a prospective, nested case-control study of men in the Health Professionals Follow-Up Study who were free of diagnosed nephrolithiasis at blood draw. During 12 years of follow-up, 356 men developed an incident symptomatic kidney stone. Using risk set sampling, controls were selected in a 2:1 ratio (n=712 controls) and matched for age, race, and year, month, and time of day of blood collection. Baseline plasma levels of 25-hydroxyvitamin D, 24,25-dihydroxyvitamin D, parathyroid hormone, calcium, phosphate, and creatinine were similar in cases and controls. Mean 1,25(OH)2D and median FGF23 levels were higher in cases than controls but differences were small and statistically nonsignificant (45.7 versus 44.2 pg/ml, P=0.07 for 1,25[OH]2D; 47.6 versus 45.1 pg/ml, P=0.08 for FGF23). However, after adjusting for body mass index, diet, plasma factors, and other covariates, the odds ratios of incident symptomatic kidney stones in the highest compared with lowest quartiles were 1.73 (95% confidence interval, 1.11 to 2.71; P for trend 0.01) for 1,25(OH)2D and 1.45 (95% confidence interval, 0.96 to 2.19; P for trend 0.03) for FGF23. There were no significant associations between other plasma factors and kidney stone risk. Higher plasma 1,25(OH)2D, even in ranges considered normal, is independently associated with higher risk of symptomatic kidney stones. Although of borderline statistical significance, these findings also suggest that higher FGF23 may be associated with risk. Copyright © 2015 by the American Society of Nephrology.

Concordance of Results from Randomized and Observational Analyses within the Same Study: A Re-Analysis of the Women's Health Initiative Limited-Access Dataset.

PubMed

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

2015-01-01

Observational studies (OS) and randomized controlled trials (RCTs) often report discordant results. In the Women's Health Initiative Calcium and Vitamin D (WHI CaD) RCT, women were randomly assigned to CaD or placebo, but were permitted to use personal calcium and vitamin D supplements, creating a unique opportunity to compare results from randomized and observational analyses within the same study. WHI CaD was a 7-year RCT of 1g calcium/400IU vitamin D daily in 36,282 post-menopausal women. We assessed the effects of CaD on cardiovascular events, death, cancer and fracture in a randomized design- comparing CaD with placebo in 43% of women not using personal calcium or vitamin D supplements- and in a observational design- comparing women in the placebo group (44%) using personal calcium and vitamin D supplements with non-users. Incidence was assessed using Cox proportional hazards models, and results from the two study designs deemed concordant if the absolute difference in hazard ratios was ≤0.15. We also compared results from WHI CaD to those from the WHI Observational Study(WHI OS), which used similar methodology for analyses and recruited from the same population. In WHI CaD, for myocardial infarction and stroke, results of unadjusted and 6/8 covariate-controlled observational analyses (age-adjusted, multivariate-adjusted, propensity-adjusted, propensity-matched) were not concordant with the randomized design results. For death, hip and total fracture, colorectal and total cancer, unadjusted and covariate-controlled observational results were concordant with randomized results. For breast cancer, unadjusted and age-adjusted observational results were concordant with randomized results, but only 1/3 other covariate-controlled observational results were concordant with randomized results. Multivariate-adjusted results from WHI OS were concordant with randomized WHI CaD results for only 4/8 endpoints. Results of randomized analyses in WHI CaD were concordant with observational analyses for 5/8 endpoints in WHI CaD and 4/8 endpoints in WHI OS.

Concordance of Results from Randomized and Observational Analyses within the Same Study: A Re-Analysis of the Women’s Health Initiative Limited-Access Dataset

PubMed Central

Bolland, Mark J.; Grey, Andrew; Gamble, Greg D.; Reid, Ian R.

2015-01-01

Background Observational studies (OS) and randomized controlled trials (RCTs) often report discordant results. In the Women’s Health Initiative Calcium and Vitamin D (WHI CaD) RCT, women were randomly assigned to CaD or placebo, but were permitted to use personal calcium and vitamin D supplements, creating a unique opportunity to compare results from randomized and observational analyses within the same study. Methods WHI CaD was a 7-year RCT of 1g calcium/400IU vitamin D daily in 36,282 post-menopausal women. We assessed the effects of CaD on cardiovascular events, death, cancer and fracture in a randomized design- comparing CaD with placebo in 43% of women not using personal calcium or vitamin D supplements- and in a observational design- comparing women in the placebo group (44%) using personal calcium and vitamin D supplements with non-users. Incidence was assessed using Cox proportional hazards models, and results from the two study designs deemed concordant if the absolute difference in hazard ratios was ≤0.15. We also compared results from WHI CaD to those from the WHI Observational Study(WHI OS), which used similar methodology for analyses and recruited from the same population. Results In WHI CaD, for myocardial infarction and stroke, results of unadjusted and 6/8 covariate-controlled observational analyses (age-adjusted, multivariate-adjusted, propensity-adjusted, propensity-matched) were not concordant with the randomized design results. For death, hip and total fracture, colorectal and total cancer, unadjusted and covariate-controlled observational results were concordant with randomized results. For breast cancer, unadjusted and age-adjusted observational results were concordant with randomized results, but only 1/3 other covariate-controlled observational results were concordant with randomized results. Multivariate-adjusted results from WHI OS were concordant with randomized WHI CaD results for only 4/8 endpoints. Conclusions Results of randomized analyses in WHI CaD were concordant with observational analyses for 5/8 endpoints in WHI CaD and 4/8 endpoints in WHI OS. PMID:26440516

Medical management to prevent recurrent nephrolithiasis in adults: a systematic review for an American College of Physicians Clinical Guideline.

PubMed

Fink, Howard A; Wilt, Timothy J; Eidman, Keith E; Garimella, Pranav S; MacDonald, Roderick; Rutks, Indulis R; Brasure, Michelle; Kane, Robert L; Ouellette, Jeannine; Monga, Manoj

2013-04-02

Optimum management to prevent recurrent kidney stones is uncertain. To evaluate the benefits and harms of interventions to prevent recurrent kidney stones. MEDLINE, Cochrane, and other databases through September 2012 and reference lists of systematic reviews and randomized, controlled trials (RCTs). 28 English-language RCTs that studied treatments to prevent recurrent kidney stones and reported stone outcomes. One reviewer extracted data, a second checked accuracy, and 2 independently rated quality and graded strength of evidence. In patients with 1 past calcium stone, low-strength evidence showed that increased fluid intake halved recurrent composite stone risk compared with no treatment (relative risk [RR], 0.45 [95% CI, 0.24 to 0.84]). Low-strength evidence showed that reducing soft-drink consumption decreased recurrent symptomatic stone risk (RR, 0.83 [CI, 0.71 to 0.98]). In patients with multiple past calcium stones, most of whom were receiving increased fluid intake, moderate-strength evidence showed that thiazides (RR, 0.52 [CI, 0.39 to 0.69]), citrates (RR, 0.25 [CI, 0.14 to 0.44]), and allopurinol (RR, 0.59 [CI, 0.42 to 0.84]) each further reduced composite stone recurrence risk compared with placebo or control, although the benefit from allopurinol seemed limited to patients with baseline hyperuricemia or hyperuricosuria. Other baseline biochemistry measures did not allow prediction of treatment efficacy. Low-strength evidence showed that neither citrate nor allopurinol combined with thiazide was superior to thiazide alone. There were few withdrawals among patients with increased fluid intake, many among those with other dietary interventions and more among those who received thiazide and citrate than among control patients. Reporting of adverse events was poor. Most trial participants had idiopathic calcium stones. Nearly all studies reported a composite (including asymptomatic) stone recurrence outcome. In patients with 1 past calcium stone, increased fluid intake reduced recurrence risk. In patients with multiple past calcium stones, addition of thiazide, citrate, or allopurinol further reduced risk. Agency for Healthcare Research and Quality.

Effect of additives on mineral trioxide aggregate setting reaction product formation.

PubMed

Zapf, Angela M; Chedella, Sharath C V; Berzins, David W

2015-01-01

Mineral trioxide aggregate (MTA) sets via hydration of calcium silicates to yield calcium silicate hydrates and calcium hydroxide (Ca[OH]2). However, a drawback of MTA is its long setting time. Therefore, many additives have been suggested to reduce the setting time. The effect those additives have on setting reaction product formation has been ignored. The objective was to examine the effect additives have on MTA's setting time and setting reaction using differential scanning calorimetry (DSC). MTA powder was prepared with distilled water (control), phosphate buffered saline, 5% calcium chloride (CaCl2), 3% sodium hypochlorite (NaOCl), or lidocaine in a 3:1 mixture and placed in crucibles for DSC evaluation. The setting exothermic reactions were evaluated at 37°C for 8 hours to determine the setting time. Separate samples were stored and evaluated using dynamic DSC scans (37°C→640°C at10°C/min) at 1 day, 1 week, 1 month, and 3 months (n = 9/group/time). Dynamic DSC quantifies the reaction product formed from the amount of heat required to decompose it. Thermographic peaks were integrated to determine enthalpy, which was analyzed with analysis of variance/Tukey test (α = 0.05). Isothermal DSC identified 2 main exothermal peaks occurring at 44 ± 12 and 343 ± 57 minutes for the control. Only the CaCl2 additive was an accelerant, which was observed by a greater exothermic peak at 101 ± 11 minutes, indicating a decreased setting time. The dynamic DSC scans produced an endothermic peak around 450°C-550°C attributed to Ca(OH)2 decomposition. The use of a few additives (NaOCl and lidocaine) resulted in significantly less Ca(OH)2 product formation. DSC was used to discriminate calcium hydroxide formation in MTA mixed with various additives and showed NaOCl and lidocaine are detrimental to MTA reaction product formation, whereas CaCl2 accelerated the reaction. Copyright © 2015 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Calcium Isotopic Compositions of Normal Mid-Ocean Ridge Basalts From the Southern Juan de Fuca Ridge

NASA Astrophysics Data System (ADS)

Zhu, Hongli; Liu, Fang; Li, Xin; Wang, Guiqin; Zhang, Zhaofeng; Sun, Weidong

2018-02-01

Mantle peridotites show that Ca is isotopically heterogeneous in Earth's mantle, but the mechanism for such heterogeneity remains obscure. To investigate the effect of partial melting on Ca isotopic fractionation and the mechanism for Ca isotopic heterogeneity in the mantle, we report high-precision Ca isotopic compositions of the normal Mid-Ocean Ridge Basalts (N-MORB) from the southern Juan de Fuca Ridge. δ44/40Ca of these N-MORB samples display a small variation ranging from 0.75 ± 0.05 to 0.86 ± 0.03‰ (relative to NIST SRM 915a, a standard reference material produced by the National Institute of Standards and Technology), which are slightly lower than the estimated Upper Mantle value of 1.05 ± 0.04‰ and the Bulk Silicate Earth (BSE) value of 0.94 ± 0.05‰. This phenomenon cannot be explained by fractional crystallization, because olivine and orthopyroxene fractional crystallization has limited influence on δ44/40Ca of N-MORB due to their low CaO contents, while plagioclase fractional crystallization cannot lead to light Ca isotopic compositions of the residue magma. Instead, the lower δ44/40Ca of N-MORB samples compared to their mantle source is most likely caused by partial melting. The offset in δ44/40Ca between N-MORB and BSE indicates that at least 0.1-0.2‰ fractionation would occur during partial melting and light Ca isotopes are preferred to be enriched in magma melt, which is in accordance with the fact that δ44/40Ca of melt-depleted peridotites are higher than fertile peridotites in literature. Therefore, partial melting is an important process that can decrease δ44/40Ca in basalts and induce Ca isotopic heterogeneity in Earth's mantle.

Cisplatin and Oxaliplatin Toxicity: Importance of Cochlear Kinetics as a Determinant for Ototoxicity

PubMed Central

Wallin, Inger; Eriksson, Sofi; Hernlund, Emma; Jerremalm, Elin; Berndtsson, Maria; Eksborg, Staffan; Arnér, Elias S. J.; Shoshan, Maria; Ehrsson, Hans; Laurell, Göran

2009-01-01

Background Cisplatin is a cornerstone anticancer drug with pronounced ototoxicity, whereas oxaliplatin, a platinum derivative with a different clinical profile, is rarely ototoxic. This difference has not been explained. Methods In HCT116 cells, cisplatin (20 μM)-induced apoptosis was reduced by a calcium chelator from 9.9-fold induction (95% confidence interval [CI] = 8.1- to 11.7-fold), to 3.1-fold induction (95% CI = 2.0- to 4.2-fold) and by superoxide scavenging from 9.3-fold (95% CI = 8.8- to 9.8-fold), to 5.1-fold (95% CI = 4.4- to 5.8-fold). A guinea pig model (n = 23) was used to examine pharmacokinetics. Drug concentrations were determined by liquid chromatography with post-column derivatization. The total platinum concentration in cochlear tissue was determined by inductively coupled plasma mass spectrometry. Drug pharmacokinetics was assessed by determining the area under the concentration–time curve (AUC). Statistical tests were two-sided. Results In HCT116 cells, cisplatin (20 μM)-induced apoptosis was reduced by a calcium chelator from 9.9-fold induction (95% confidence interval [CI] = 8.1- to 11.7-fold to 3.1-fold induction) (95% CI = 2.0- to 4.2-fold) and by superoxide scavenging (from 9.3-fold, 95% CI = 8.8- to 9.8-fold, to 5.1-fold, 95% CI = 4.4- to 5.8-fold). Oxaliplatin (20 μM)-induced apoptosis was unaffected by calcium chelation (from 7.1- to 6.2-fold induction) and by superoxide scavenging (from 5.9- to 5.6-fold induction). In guinea pig cochlea, total platinum concentration (0.12 vs 0.63 μg/kg, respectively, P = .008) and perilymphatic drug concentrations (238 vs 515 μM × minute, respectively, P < .001) were lower after intravenous oxaliplatin treatment (16.6 mg/kg) than after equimolar cisplatin treatment (12.5 mg/kg). However, after a non-ototoxic cisplatin dose (5 mg/kg) or the same oxaliplatin dose (16.6 mg/kg), the AUC for perilymphatic concentrations was similar, indicating that the two drugs have different cochlear pharmacokinetics. Conclusion Cisplatin- but not oxaliplatin-induced apoptosis involved superoxide-related pathways. Lower cochlear uptake of oxaliplatin than cisplatin appears to be a major explanation for its lower ototoxicity. PMID:19116379

Role of diuretics, β blockers, and statins in increasing the risk of diabetes in patients with impaired glucose tolerance: reanalysis of data from the NAVIGATOR study.

PubMed

Shen, Lan; Shah, Bimal R; Reyes, Eric M; Thomas, Laine; Wojdyla, Daniel; Diem, Peter; Leiter, Lawrence A; Charbonnel, Bernard; Mareev, Viacheslav; Horton, Edward S; Haffner, Steven M; Soska, Vladimir; Holman, Rury; Bethel, M Angelyn; Schaper, Frank; Sun, Jie-Lena; McMurray, John J V; Califf, Robert M; Krum, Henry

2013-12-09

To examine the degree to which use of β blockers, statins, and diuretics in patients with impaired glucose tolerance and other cardiovascular risk factors is associated with new onset diabetes. Reanalysis of data from the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial. NAVIGATOR trial. Patients who at baseline (enrolment) were treatment naïve to β blockers (n=5640), diuretics (n=6346), statins (n=6146), and calcium channel blockers (n=6294). Use of calcium channel blocker was used as a metabolically neutral control. Development of new onset diabetes diagnosed by standard plasma glucose level in all participants and confirmed with glucose tolerance testing within 12 weeks after the increased glucose value was recorded. The relation between each treatment and new onset diabetes was evaluated using marginal structural models for causal inference, to account for time dependent confounding in treatment assignment. During the median five years of follow-up, β blockers were started in 915 (16.2%) patients, diuretics in 1316 (20.7%), statins in 1353 (22.0%), and calcium channel blockers in 1171 (18.6%). After adjusting for baseline characteristics and time varying confounders, diuretics and statins were both associated with an increased risk of new onset diabetes (hazard ratio 1.23, 95% confidence interval 1.06 to 1.44, and 1.32, 1.14 to 1.48, respectively), whereas β blockers and calcium channel blockers were not associated with new onset diabetes (1.10, 0.92 to 1.31, and 0.95, 0.79 to 1.13, respectively). Among people with impaired glucose tolerance and other cardiovascular risk factors and with serial glucose measurements, diuretics and statins were associated with an increased risk of new onset diabetes, whereas the effect of β blockers was non-significant. ClinicalTrials.gov NCT00097786.

Changing composition of renal calculi in patients with musculoskeletal anomalies.

PubMed

Gnessin, Ehud; Mandeville, Jessica A; Handa, Shelly E; Lingeman, James E

2011-09-01

Calculi from patients with musculoskeletal (MS) anomalies who are largely immobile and prone to urinary infections have been traditionally composed primarily of struvite and carbonate apatite. Because of substantial improvements in the care of these patients in recent decades, stone etiology may have shifted from infectious to metabolic. We assessed the composition of renal calculi and metabolic characteristics in a contemporary cohort of patients with MS anomalies who underwent percutaneous nephrolithotomy (PCNL). Retrospective analysis of patients who underwent PCNL between April 1999 and June 2009 and had follow-up 24-hour urine studies was performed. Patients with MS anomalies included spinal cord injury, myelomeningocele, muscular dystrophy, multiple sclerosis, cerebral palsy, or other clinical syndromes causing kyphoscoliosis and contractures. Our cohort included 33 patients with MS anomalies and 334 consecutive patients as a control group who underwent PCNL and had metabolic workup. Stones were infectious in etiology in 18.4% and 6.2% in MS and control groups, respectively. Thus, most patients harbored stones of metabolic origin. Metabolic stones in the MS group were composed of 52.7% hydroxyapatite, 10.5% calcium oxalate, 7.9% brushite, 2.6% uric acid, 0% cystine, and 7.9% other. Metabolic stones in the control group were 50.5% calcium oxalate, 16.4% hydroxyapatite, 11.5% brushite, 10.8% uric acid, 4.3% cystine, and 0.3% other. Mean 24-hour urine values for patients with metabolic stones in MS/control groups were volume 2.18/1.87 L/d, pH 6.78/6.05, calcium to creatinine ratio 220/151 mg/g, and oxalate 44.8/39.5 mg/d. Although patients with MS anomalies are traditionally thought to harbor infection-related calculi, most will be found to have calculi of metabolic etiology. The incidence of calcium phosphate stones is high in this group of patients, perhaps reflecting their high urinary pH.

Deterioration of the mechanical properties of calcium phosphate cements with Poly (γ-glutamic acid) and its strontium salt after in vitro degradation.

PubMed

Liang, Ting; Gao, Chun-Xia; Yang, Lei; Saijilafu; Yang, Hui-Lin; Luo, Zong-Ping

2017-11-01

The mechanical reliability of calcium phosphate cements has restricted their clinical application in load-bearing locations. Although their mechanical strength can be improved using a variety of strategies, their fatigue properties are still unclear, especially after degradation. The evolutions of uniaxial compressive properties and the fatigue behavior of calcium phosphate cements incorporating poly (γ-glutamic acid) and its strontium salt after different in vitro degradation times were investigated in the present study. Compressive strength decreased from the 61.2±5.4MPa of the original specimen, to 51.1±4.4, 42.2±3.8, 36.8±2.4 and 28.9±3.2MPa following degradation for one, two, three and four weeks, respectively. Fatigue life under same loading condition also decreased with increasing degradation time. The original specimens remained intact for one million cycles (run-out) under a maximum stress of 30MPa. After degradation for one to four weeks, the specimens were able to withstand maximum stress of 20, 15, 10 and 10MPa, respectively until run-out. Defect volume fraction within the specimens increased from 0.19±0.021% of the original specimen to 0.60±0.19%, 1.09±0.04%, 2.68±0.64% and 7.18±0.34% at degradation time of one, two, three and four weeks, respectively. Therefore, we can infer that the primary cause of the deterioration of the mechanical properties was an increasing in micro defects induced by degradation, which promoted crack initiation and propagation, accelerating the final mechanical failure of the bone cement. This study provided the data required for enhancing the mechanical reliability of the calcium phosphate cements after different degradation times, which will be significant for the modification of load-bearing biodegradable bone cements to match clinical application. Copyright © 2017 Elsevier Ltd. All rights reserved.

Role of diuretics, β blockers, and statins in increasing the risk of diabetes in patients with impaired glucose tolerance: reanalysis of data from the NAVIGATOR study

PubMed Central

Shen, Lan; Shah, Bimal R; Reyes, Eric M; Thomas, Laine; Wojdyla, Daniel; Diem, Peter; Leiter, Lawrence A; Charbonnel, Bernard; Mareev, Viacheslav; Horton, Edward S; Haffner, Steven M; Soska, Vladimir; Holman, Rury; Bethel, M Angelyn; Schaper, Frank; Sun, Jie-Lena; McMurray, John JV; Califf, Robert M

2013-01-01

Objective To examine the degree to which use of β blockers, statins, and diuretics in patients with impaired glucose tolerance and other cardiovascular risk factors is associated with new onset diabetes. Design Reanalysis of data from the Nateglinide and Valsartan in Impaired Glucose Tolerance Outcomes Research (NAVIGATOR) trial. Setting NAVIGATOR trial. Participants Patients who at baseline (enrolment) were treatment naïve to β blockers (n=5640), diuretics (n=6346), statins (n=6146), and calcium channel blockers (n=6294). Use of calcium channel blocker was used as a metabolically neutral control. Main outcome measures Development of new onset diabetes diagnosed by standard plasma glucose level in all participants and confirmed with glucose tolerance testing within 12 weeks after the increased glucose value was recorded. The relation between each treatment and new onset diabetes was evaluated using marginal structural models for causal inference, to account for time dependent confounding in treatment assignment. Results During the median five years of follow-up, β blockers were started in 915 (16.2%) patients, diuretics in 1316 (20.7%), statins in 1353 (22.0%), and calcium channel blockers in 1171 (18.6%). After adjusting for baseline characteristics and time varying confounders, diuretics and statins were both associated with an increased risk of new onset diabetes (hazard ratio 1.23, 95% confidence interval 1.06 to 1.44, and 1.32, 1.14 to 1.48, respectively), whereas β blockers and calcium channel blockers were not associated with new onset diabetes (1.10, 0.92 to 1.31, and 0.95, 0.79 to 1.13, respectively). Conclusions Among people with impaired glucose tolerance and other cardiovascular risk factors and with serial glucose measurements, diuretics and statins were associated with an increased risk of new onset diabetes, whereas the effect of β blockers was non-significant. Trial registration ClinicalTrials.gov NCT00097786. PMID:24322398

[Scientific evidence about the role of yogurt and other fermented milks in the healthy diet for the Spanish population].

PubMed

Moreno Aznar, Luis A; Cervera Ral, Pilar; Ortega Anta, Rosa M; Díaz Martín, Juan José; Baladia, Eduard; Basulto, Julio; Bel Serrat, Silvia; Iglesia Altaba, Iris; López-Sobaler, Ana M; Manera, María; Rodríguez Rodríguez, Elena; Santaliestra Pasías, Alba M; Babio, Nancy; Salas-Salvadó, Jordi

2013-11-01

Milk products contain proteins of high biologic value and digestibility; they also contain fat, carbohydrates, vitamins and minerals, specially calcium and phosphorus. Diversification of milk products consumption allows a high consumptiom of the above mentioned products, optimizing nutrient intake. In Spain, food consumption of milk products lower than the recommended amounts was observed in 20 to 40 % of the children and 30 to 45 % of the adults. Milk products represent 44 to 70 % of calcium intake in the Spanish population. Milk products consumption is positively associated with a high bone mineral density. More than 35 % of children and adults in Spain had calcium intakes below the national recommendations. Yogur contains less lactose than regular milk and fermenting milk bacteries express functioning lactase. Yogur intake is recommended to improve lactose digestion in individuals having lactose maldigestion. It seems reasonable to recommend yogur to improve calcium absorption, at least in post-menopausal women, and also for decreasing incidence and duration of infectious gastrointestinal disorders in children. Fermented milk products consumption, before, during and after medical eradication of Helicobacter Pylori, increases 5 to 10 % the effect of the specific drug therapy. Its consumption before, during and after antibiotic treatment, could also reduce the risk of diarrhea associated with the use of the above mentioned drugs. The Spanish Federation of Nutrition, Feeding and Dietetic Societies (FESNAD) recommend the following consumption of milk and milk products: Adults, 2-3 portions/day; school-age children, 2-3 portions/day; adolescents, 3-4 portions/day; pregnant and lactating women and during menopause, 3-4 portions/day; elderly, 2-4 portions/day. Considering yogur and fermented milk consumption show some advantages when compared with other milk products, we can recommend yogur within a daily and varied consumption of milk products. Copyright AULA MEDICA EDICIONES 2013. Published by AULA MEDICA. All rights reserved.

Calcium isotope systematics at hydrothermal conditions: Mid-ocean ridge vent fluids and experiments in the CaSO4-NaCl-H2O system

NASA Astrophysics Data System (ADS)

Scheuermann, Peter P.; Syverson, Drew D.; Higgins, John A.; Pester, Nicholas J.; Seyfried, William E.

2018-04-01

Two sets of hydrothermal experiments were performed to explore Ca isotope fractionation and exchange rates at hydrothermal conditions (410-450 °C, 31.0-50.0 MPa). The first set of experiments determined the magnitude of vapor-liquid Ca isotope fractionation and anhydrite solubility in the CaSO4-NaCl-H2O system. The data indicate no statistical difference between the Ca isotopic composition of coexisting vapor and liquid. The second set of experiments utilized an anomalous 43Ca spike to determine the rate of Ca exchange between fluid and anhydrite as a function of total dissolved Ca concentration. Results show that the rate of exchange increases with dissolved Ca concentrations (12-23 mM/kg), but no change in exchange rate is observed when the Ca concentration increases from 23 to 44 mM/kg Ca. 74-142 days are required to achieve 90% anhydrite-fluid Ca isotope exchange at the conditions investigated, while only several hours are necessary for vapor-liquid isotopic equilibrium. The lack of vapor-liquid Ca isotope fractionation in our experiments is consistent with δ44Ca of mid-ocean ridge hydrothermal vent fluids that remain constant, regardless of chlorinity. Moreover, the narrow range of end member fluid δ44Ca, -0.98 to -1.13‰ (SW), is largely indistinguishable from MORB δ44Ca, suggesting that neither phase separation nor fluid-rock interactions at depth significantly fractionate Ca isotopes in modern high-temperature mid-ocean ridge hydrothermal systems.

Origins of mass-dependent and mass-independent Ca isotope variations in meteoritic components and meteorites

NASA Astrophysics Data System (ADS)

Bermingham, K. R.; Gussone, N.; Mezger, K.; Krause, J.

2018-04-01

The Ca isotope composition of meteorites and their components may vary due to mass-dependent and/or -independent isotope effects. In order to evaluate the origin of these effects, five amoeboid olivine aggregates (AOAs), three calcium aluminum inclusions (CAIs), five chondrules (C), a dark inclusion from Allende (CV3), two dark fragments from North West Africa 753 (NWA 753; R3.9), and a whole rock sample of Orgueil (CI1) were analyzed. This is the first coupled mass-dependent and -independent Ca isotope dataset to include AOAs, a dark inclusion, and dark fragments. Where sample masses permit, Ca isotope data are reported with corresponding petrographic analyses and rare earth element (REE) relative abundance patterns. The CAIs and AOAs are enriched in light Ca isotopes (δ44/40Ca -5.32 to +0.72, where δ44/40Ca is reported relative to SRM 915a). Samples CAI 5 and AOA 1 have anomalous Group II REE patterns. These REE and δ44/40Ca data suggest that the CAI 5 and AOA 1 compositions were set via kinetic isotope fractionation during condensation and evaporation. The remaining samples show mass-dependent Ca isotope variations which cluster between δ44/40Ca +0.53 and +1.59, some of which are coupled with unfractionated REE abundance patterns. These meteoritic components likely formed through the coaccretion of the evaporative residue and condensate following Group II CAI formation or their chemical and isotopic signatures were decoupled (e.g., via nebular or parent-body alteration). The whole rock sample of Orgueil has a δ44/40Ca +0.67 ± 0.18 which is in agreement with most published data. Parent-body alteration, terrestrial alteration, and variable sampling of Ca-rich meteoritic components can have an effect on δ44/40Ca compositions in whole rock meteorites. Samples AOA 1, CAI 5, C 2, and C 4 display mass-independent 48/44Ca anomalies (ε48/44Ca +6 to +12) which are resolved from the standard composition. Other samples measured for these effects (AOA 5, CAI 1, CAI 2, C 3, D 1, D 2, D 3) possess the same 48/44Ca isotope composition as the standard within analytical uncertainty. These data indicate a heterogeneous distribution of 48Ca in the early solar nebula during formation of CAIs, AOAs, and chondrules. In a ε48/44Ca vs. δ44/40Ca plot, no strong correlation is evident which suggests that the thermal processing event which caused a heterogeneous distribution of ε48/44Ca in the solar nebula is unlikely to be directly related to the thermal processing event that caused coupled REE and Ca mass-dependent isotopic fractionation in meteoritic components.

Hyaluronan and calcium carbonate hybrid nanoparticles for colorectal cancer chemotherapy

NASA Astrophysics Data System (ADS)

Bai, Jinghui; Xu, Jian; Zhao, Jian; Zhang, Rui

2017-09-01

A hybrid drug delivery system (DDS) composed of hyaluronan and calcium carbonate (CC) was developed. By taking advantage of the tumor-targeting ability of hyaluronan and the drug-loading property of CC, the well-formed hyaluronan-CC nanoparticles were able to serve as a DDS targeting colorectal cancer with a decent drug loading content, which is beneficial in the chemotherapy of colorectal cancer. In this study, hyaluronan-CC nanoparticles smaller than 100 nm were successfully developed to load the wide-range anti-cancer drug adriamycin (Adr) to construct hyaluronan-CC/Adr nanoparticles. On the other hand, we also found that hyaluronan-CC/Adr nanoparticles can possibly increase the uptake ratio of Adr into HT29 colorectal cancer cells when compared with hyaluronan-free nanoparticles (CC/Adr) via the CD44 receptor-mediated endocytosis via competitive uptake and in vivo imaging assays. Note that both in vitro (CCK-8 assay on HT29 cells) and in vivo (anti-cancer assay on HT-29 tumor-bearing nude mice model) experiments revealed that hyaluronan-CC/Adr nanoparticles exhibited stronger anti-cancer activity than free Adr or CC/Adr nanoparticles with minimized toxic side effects and preferable cancer-suppression potential.

Water permeability, hybrid layer long-term integrity and reaction mechanism of a two-step adhesive system.

PubMed

Grégoire, Geneviève; Dabsie, Firas; Delannée, Mathieu; Akon, Bernadette; Sharrock, Patrick

2010-07-01

Our aim was to investigate the reaction mechanism of formation of the hybrid layer by a HEMA-containing self-etch adhesive and to study fluid filtration, contact angle and interfacial ultrastructure by SEM following a 1 year ageing period. Acidic behaviour and chemical interactions between Silorane System Adhesive and dentine were studied by potentiometric titrations, atomic absorption spectroscopy and infrared spectroscopy. The hydrophilicity of the adhesive was evaluated using the sessile drop method and dentine permeability by hydraulic conductance. The morphological study of the dentine/adhesive system interface was conducted using SEM. The Silorane System Adhesive behaved as a multi-acid with several different pK(a) values. When the adhesive was in contact with dentine, the acid was progressively consumed and calcium ions were released. The acrylate substituted phosphonate bound strongly to apatite crystals. The polyacrylic acid copolymer reacted with calcium ions and formed an interpenetrating polymer network (IPN). Water contact angle measurements showed rapid spreading on primer (angles reached 15 degrees at 30s) and larger contact angles when the Silorane bonding layer was added (from over 60 degrees to 44 degrees ). A thick, homogeneous hybrid layer was observed both initially and after 1 year of ageing, with a corresponding hydraulic conductance of -48.50% initially and -52.07% at 12 months. The Silorane System Adhesive is capable of both dissolving calcium ions and binding to apatite surfaces. The results showed the hydrophilicity of the adhesive, which formed an IPN-like hybrid layer that conserved adequate impermeability over a 1-year period. Copyright 2010 Elsevier Ltd. All rights reserved.

Prevalence of severe subclinical coronary artery disease on cardiac CT and MRI in patients with extra-cardiac arterial disease.

PubMed

den Dekker, M A M; van den Dungen, J J A M; Tielliu, I F J; Tio, R A; Jaspers, M M J J R; Oudkerk, M; Vliegenthart, R

2013-12-01

Patients with extra-cardiac arterial disease (ECAD) are at high risk of coronary artery disease (CAD). Prevalence of silent, significant CAD in patients with stenotic or aneurysmal ECAD was examined. Early detection and treatment may reduce CAD mortality in this high-risk group. ECAD patients without cardiac complaints underwent computed tomography (CT) for calcium scoring, coronary CT angiography (cCTA) if calcium score was 1,000 or under, and adenosine perfusion magnetic resonance imaging (APMR) if there was no left main stenosis. Significant CAD was defined as calcium score over 1,000, cCTA-detected coronary stenosis of at least 50% lumen diameter, and/or APMR-detected inducible myocardial ischemia. In cases of left main stenosis (or equivalent) or myocardial ischemia, patients were referred to a cardiologist. The prevalence of significant CAD was 56.8% (95% CI 47.5 to 66.0). One-hundred and eleven patients were included. Eighty-four patients (76%) had stenotic ECAD, and 27 (24%) had aneurysmal disease. In patients with stenotic ECAD, significant coronary stenosis was present in 32 (38%) and inducible ischemia in eight (12%). Corresponding results in aneurysmal ECAD were eight (30%) and two (11%), respectively (p for difference >.05). Sixteen (19%) patients with stenotic and six (22%) with aneurysmal ECAD were referred to a cardiologist, with subsequent cardiac intervention in seven (44%) and three (50%), respectively (both p >.05). Patients with stenotic or aneurysmal ECAD have a high prevalence of silent, significant CAD. Copyright © 2013 European Society for Vascular Surgery. Published by Elsevier Ltd. All rights reserved.

In vitro fertilization of in vitro-matured equine oocytes: effect of maturation medium, duration of maturation, and sperm calcium ionophore treatment, and comparison with rates of fertilization in vivo after oviductal transfer.

PubMed

Hinrichs, K; Love, C C; Brinsko, S P; Choi, Y H; Varner, D D

2002-07-01

Three experiments were conducted to evaluate the effect of oocyte and sperm treatments on rates of in vitro fertilization (IVF) in the horse and to determine the capacity of in vitro-matured horse oocytes to be fertilized in vivo. There was no effect of duration of oocyte maturation (24 vs. 42 h) or calcium ionophore concentration during sperm capacitation (3 microM vs. 7.14 microM) on in vitro fertilization rates. Oocytes matured in 100% follicular fluid had significantly higher fertilization (13% to 24%) than did oocytes matured in maturation medium or in 20% follicular fluid (0% to 12%; P < 0.05). There was no significant difference in fertilization rate among 3 sperm treatments utilizing 7.14 microM calcium ionophore (12% to 21%). Of in vitro-matured oocytes recovered 40-44 h after transfer to the oviducts of inseminated mares, 77% showed normal fertilization (2 pronuclei to normal cleavage). Cleavage to 2 or more cells was seen in 22% of oocytes matured in follicular fluid and 63% of oocytes matured in maturation medium; this difference was significant (P < 0.05). We conclude that in vitro-matured horse oocytes are capable of being fertilized at high rates in the appropriate environment and that in vitro maturation of oocytes in follicular fluid increases fertilization rate in vitro but reduces embryo development after fertilization in vivo. Further work is needed to determine the optimum environment for sperm capacitation and IVF in the horse.

Reduced polyspermic fertilization of porcine oocytes utilizing elevated bicarbonate and reduced calcium concentrations in a single-medium system.

PubMed

Herrick, J R; Conover-Sparman, M L; Krisher, R L

2003-01-01

The development of efficient systems for in vitro production of porcine embryos has been hampered by a high incidence of polyspermic fertilization. A recently developed single-medium system for porcine in vitro maturation (IVM), IVF and in vitro embryo culture (IVC) (Purdue Porcine Medium; PPM) was modified with elevated bicarbonate (44 mM) and reduced calcium concentrations (1.7 mM) for IVF (PPMfert.2). Oocyte penetration was evaluated after maturation in PPMmat (0.5 mg mL(-1) hyaluronan, 0.6 mM cysteine, 10 ng mL(-1) epidermal growth factor (EGF), 0.1 U mL(-1) porcine LH and FSH, and 1 x Minimal Essential Medium (MEM) vitamins) and fertilization (5 h with 5 x 10(5) sperm mL(-1)) in either PPMfert.2 or mTBM (20 mM Tris, 0.0 mM bicarbonate, 7.5 mM calcium). Embryonic development (cleavage and blastocyst stages) was assessed after culture in PPM1 and PPM2. Although penetration was lower in PPMfert.2 (69.9%) compared with mTBM (83.9%), 48.8% of penetrated oocytes were fertilized normally in PPMfert.2 compared with only 27.8% normal fertilization in mTBM. More oocytes cleaved in PPMfert.2 (77.9% v. 53.7%), but development to the blastocyst stage was not different between treatments (14.1% v. 14.3%). Further work is needed to improve embryonic development, but reduced polyspermic penetration is an important step in the optimization of the PPM system for in vitro porcine embryo production.

Chromospherically Active Stars in the RAdial Velocity Experiment (RAVE) Survey. I. The Catalog

NASA Astrophysics Data System (ADS)

Žerjal, M.; Zwitter, T.; Matijevič, G.; Strassmeier, K. G.; Bienaymé, O.; Bland-Hawthorn, J.; Boeche, C.; Freeman, K. C.; Grebel, E. K.; Kordopatis, G.; Munari, U.; Navarro, J. F.; Parker, Q. A.; Reid, W.; Seabroke, G.; Siviero, A.; Steinmetz, M.; Wyse, R. F. G.

2013-10-01

RAVE, the unbiased magnitude limited survey of southern sky stars, contained 456,676 medium-resolution spectra at the time of our analysis. Spectra cover the Ca II infrared triplet (IRT) range, which is a known indicator of chromospheric activity. Our previous work classified all spectra using locally linear embedding. It identified 53,347 cases with a suggested emission component in calcium lines. Here, we use a spectral subtraction technique to measure the properties of this emission. Synthetic templates are replaced by the observed spectra of non-active stars to bypass the difficult computations of non-local thermal equilibrium profiles of the line cores and stellar parameter dependence. We derive both the equivalent width of the excess emission for each calcium line on a 5 Å wide interval and their sum EWIRT for ~44,000 candidate active dwarf stars with signal-to-noise ratio >20, with no cuts on the basis of the source of their emission flux. From these, ~14,000 show a detectable chromospheric flux with at least a 2σ confidence level. Our set of active stars vastly enlarges previously known samples. Atmospheric parameters and, in some cases, radial velocities of active stars derived from automatic pipelines suffer from systematic shifts due to their shallower calcium lines. We re-estimate the effective temperature, metallicity, and radial velocities for candidate active stars. The overall distribution of activity levels shows a bimodal shape, with the first peak coinciding with non-active stars and the second with the pre-main-sequence cases. The catalog will be made publicly available with the next RAVE public data releases.

Quantitative assessment of citric acid in lemon juice, lime juice, and commercially-available fruit juice products.

PubMed

Penniston, Kristina L; Nakada, Stephen Y; Holmes, Ross P; Assimos, Dean G

2008-03-01

Knowledge of the citric acid content of beverages may be useful in nutrition therapy for calcium urolithiasis, especially among patients with hypocitraturia. Citrate is a naturally-occurring inhibitor of urinary crystallization; achieving therapeutic urinary citrate concentration is one clinical target in the medical management of calcium urolithiasis. When provided as fluids, beverages containing citric acid add to the total volume of urine, reducing its saturation of calcium and other crystals, and may enhance urinary citrate excretion. Information on the citric acid content of fruit juices and commercially-available formulations is not widely known. We evaluated the citric acid concentration of various fruit juices. The citric acid content of 21 commercially-available juices and juice concentrates and the juice of three types of fruits was analyzed using ion chromatography. Lemon juice and lime juice are rich sources of citric acid, containing 1.44 and 1.38 g/oz, respectively. Lemon and lime juice concentrates contain 1.10 and 1.06 g/oz, respectively. The citric acid content of commercially available lemonade and other juice products varies widely, ranging from 0.03 to 0.22 g/oz. Lemon and lime juice, both from the fresh fruit and from juice concentrates, provide more citric acid per liter than ready-to-consume grapefruit juice, ready-to-consume orange juice, and orange juice squeezed from the fruit. Ready-to-consume lemonade formulations and those requiring mixing with water contain < or =6 times the citric acid, on an ounce-for-ounce basis, of lemon and lime juice.

Relation of Aortic Valve Calcium to Chronic Kidney Disease (from the Chronic Renal Insufficiency Cohort [CRIC] Study)

PubMed Central

Guerraty, Marie A.; Chai, Boyang; Hsu, Jesse Yenchih; Ojo, Akinlolu O.; Gao, Yanlin; Yang, Wei; Keane, Martin G.; Budoff, Matthew J.; Mohler, Emile R.

2015-01-01

Although subjects with chronic kidney disease (CKD) are at markedly increased risk for cardiovascular mortality, the relationship between CKD and aortic valve calcification has not been fully elucidated. Also, few data are available on the relationship of aortic valve calcification and earlier stages of CKD. We sought to assess the relationship of aortic valve calcium (AVC) with estimated glomerular filtration rate (eGFR), traditional and novel cardiovascular risk factors, and markers of bone metabolism in the Chronic Renal Insufficiency Cohort (CRIC) Study. All patients who underwent aortic valve scanning in the CRIC study were included. The relationship between AVC and eGFR, traditional and novel cardiovascular risk factors, and markers of calcium metabolism were analyzed using both unadjusted and adjusted regression models. A total of 1964 CRIC participants underwent computed tomography for AVC quantification. Decreased renal function was independently associated with increased levels of AVC (eGFR 47.11 ml/min/1.73m2, 44.17 ml/min/1.73m2, and 39 ml/min/1.73m2, respectively, p< 0.001). This association persisted after adjusting for traditional, but not novel, AVC risk factors. Adjusted regression models identified several traditional and novel risk factors for AVC in patients with CKD. There was a difference in AVC risk factors between black and non-black patients. In conclusion, our study shows that eGFR is associated in a dose-dependent manner with AVC in patients with CKD, and this association is independent of traditional cardiovascular risk factors. PMID:25791240

Effect of high dietary sodium on bone turnover markers and urinary calcium excretion in Korean postmenopausal women with low bone mass.

PubMed

Park, S M; Joung, J Y; Cho, Y Y; Sohn, S Y; Hur, K Y; Kim, J H; Kim, S W; Chung, J H; Lee, M K; Min, Y-K

2015-03-01

High salt intake is a well-recognized risk factor of osteoporosis for its modulating effect on calcium metabolism. To understand the effect of dietary sodium on bone turnover, we evaluated the association between urinary sodium excretion and bone turnover markers in Korean postmenopausal women with low bone mass. A retrospective review of medical records at a single institution identified 537 postmenopausal women who were first diagnosed with osteopenia or osteoporosis between 2008 and 2013. Subjects were stratified by low (<2 g/day, n=77), moderate (2-4.4 g/day, n=354) and high (⩾4.4 g/day, n=106) sodium excretion. A 24-h urine was collected to estimate sodium, calcium and creatinine. Bone turnover markers and calciotropic hormones were measured in serum. Bone mineral density (BMD) was assessed using dual-energy X-ray absorptiometry. Sodium intake was positively associated with urinary sodium excretion (P=0.006, r=0.29). Bone turnover markers were significantly higher in the moderate-to-high urinary sodium excretion group (⩾2 g/day) than in the low urinary sodium excretion group (<2 g/day); CTX-I (C-telopeptides of type I collagen) was 21.3% higher (P=0.001) and osteocalcin (OC) was 15.7% higher (P=0.004). Calciotropic hormones and BMD were not significantly different across the sodium excretion groups. High urinary sodium excretion (⩾2 g/day) increased bone turnover markers in Korean postmenopausal women, suggesting that excessive sodium intake might accelerate bone turnover.

Effects of Ocean Acidification on Juvenile Red King Crab (Paralithodes camtschaticus) and Tanner Crab (Chionoecetes bairdi) Growth, Condition, Calcification, and Survival

PubMed Central

Long, William Christopher; Swiney, Katherine M.; Harris, Caitlin; Page, Heather N.; Foy, Robert J.

2013-01-01

Ocean acidification, a decrease in the pH in marine waters associated with rising atmospheric CO2 levels, is a serious threat to marine ecosystems. In this paper, we determine the effects of long-term exposure to near-future levels of ocean acidification on the growth, condition, calcification, and survival of juvenile red king crabs, Paralithodes camtschaticus, and Tanner crabs, Chionoecetes bairdi. Juveniles were reared in individual containers for nearly 200 days in flowing control (pH 8.0), pH 7.8, and pH 7.5 seawater at ambient temperatures (range 4.4–11.9 °C). In both species, survival decreased with pH, with 100% mortality of red king crabs occurring after 95 days in pH 7.5 water. Though the morphology of neither species was affected by acidification, both species grew slower in acidified water. At the end of the experiment, calcium concentration was measured in each crab and the dry mass and condition index of each crab were determined. Ocean acidification did not affect the calcium content of red king crab but did decrease the condition index, while it had the opposite effect on Tanner crabs, decreasing calcium content but leaving the condition index unchanged. This suggests that red king crab may be able to maintain calcification rates, but at a high energetic cost. The decrease in survival and growth of each species is likely to have a serious negative effect on their populations in the absence of evolutionary adaptation or acclimatization over the coming decades. PMID:23593357

THE FIRST DISTANCE CONSTRAINT ON THE RENEGADE HIGH-VELOCITY CLOUD COMPLEX WD

DOE Office of Scientific and Technical Information (OSTI.GOV)

Peek, J. E. G.; Roman-Duval, Julia; Tumlinson, Jason

2016-09-10

We present medium-resolution, near-ultraviolet Very Large Telescope/FLAMES observations of the star USNO-A0600-15865535. We adapt a standard method of stellar typing to our measurement of the shape of the Balmer ϵ absorption line to demonstrate that USNO-A0600-15865535 is a blue horizontal branch star, residing in the lower stellar halo at a distance of 4.4 kpc from the Sun. We measure the H and K lines of singly ionized calcium and find two isolated velocity components, one originating in the disk, and one associated with the high-velocity cloud complex WD. This detection demonstrated that complex WD is closer than ∼4.4 kpc andmore » is the first distance constraint on the +100 km s{sup −1} Galactic complex of clouds. We find that complex WD is not in corotation with the Galactic disk, which has been assumed for decades. We examine a number of scenarios and find that the most likely scenario is that complex WD was ejected from the solar neighborhood and is only a few kiloparsecs from the Sun.« less

Calcium Isotope (δ44/40Ca) Composition of Morozovella Velascoensis During the Paleocene Eocene Thermal Maximum Ocean Acidification Event

NASA Astrophysics Data System (ADS)

Kitch, G. D.; Jacobson, A. D.; Hurtgen, M.; Sageman, B. B.; Harper, D. T.; Zachos, J. C.

2017-12-01

Ocean acidification (OA) events are transient disruptions to the carbonate chemistry of seawater that involve decreases in pH, [CO32-] and carbonate mineral saturation states (Ω). Numerical modeling studies predict that the Ca isotope (δ44/40Ca) composition of primary marine carbonate should be sensitive to OA1, and recent evidence from the rock record may support this hypothesis2. Boron isotope (δ11B) data for the planktonic foraminifera Morozovella velascoensis indicate that the Paleocene-Eocene Thermal Maximum (PETM; 55 Mya) was an interval of pronounced OA3, although the Ca isotope composition of the bulk carbonate record appears to show post-burial diagenetic effects4. To further evaluate the Ca isotope proxy, we used a high-precision (2σSD=±0.04‰), double-spike (43Ca-42Ca) TIMS method5 to measure δ44/40Ca values of well-preserved M. velascoensis tests spanning the PETM. M. velascoensis tests (250-355 µm) were picked from samples recovered during ODP Leg 198, Site 1209 on Shatsky Rise in the equatorial Pacific. Five M. velascoensis tests were combined per sample, dissolved, spiked, and analyzed using a Triton TIMS. Repeat dissolutions of ten samples gave δ44/40Ca values within ±0.04‰ of the original measurements. Method and procedural blanks were negligible. δ44/40Ca values are elevated, even before the negative carbon isotope excursion (CIE) that marks the PETM. When δ11/10B values decrease during the CIE, δ44/40Ca values remain elevated, but then decrease by 0.10‰ as δ11B values return to pre-CIE levels. The apparent inverse correlation between δ44/40Ca and δ11B values suggests that Ca isotope fractionation by M. velascoensis was sensitive to OA. A decrease in pH indicated by lower δ11B values is consistent with higher δ44/40Ca values (decreased fractionation) due to elevated [Ca2+]/[CO32-] ratios and reduced W. The Ca isotope composition of pristine foraminiferal calcite may have potential for reconstructing [CO32-]. The current, preliminary dataset may indicate changes in [CO32-] prior to the CIE. 1Nielsen et al., 2012. 2Du Vivier et al., 2015. 3Penman et al., 2014. 4Griffith et al., 2015. 5Lehn et al., 2013.

Optimization and application of ICPMS with dynamic reaction cell for precise determination of 44Ca/40Ca isotope ratios.

PubMed

Boulyga, Sergei F; Klötzli, Urs; Stingeder, Gerhard; Prohaska, Thomas

2007-10-15

An inductively coupled plasma mass spectrometer with dynamic reaction cell (ICP-DRC-MS) was optimized for determining (44)Ca/(40)Ca isotope ratios in aqueous solutions with respect to (i) repeatability, (ii) robustness, and (iii) stability. Ammonia as reaction gas allowed both the removal of (40)Ar+ interference on (40)Ca+ and collisional damping of ion density fluctuations of an ion beam extracted from an ICP. The effect of laboratory conditions as well as ICP-DRC-MS parameters such a nebulizer gas flow rate, rf power, lens potential, dwell time, or DRC parameters on precision and mass bias was studied. Precision (calculated using the "unbiased" or "n - 1" method) of a single isotope ratio measurement of a 60 ng g(-1) calcium solution (analysis time of 6 min) is routinely achievable in the range of 0.03-0.05%, which corresponded to the standard error of the mean value (n = 6) of 0.012-0.020%. These experimentally observed RSDs were close to theoretical precision values given by counting statistics. Accuracy of measured isotope ratios was assessed by comparative measurements of the same samples by ICP-DRC-MS and thermal ionization mass spectrometry (TIMS) by using isotope dilution with a (43)Ca-(48)Ca double spike. The analysis time in both cases was 1 h per analysis (10 blocks, each 6 min). The delta(44)Ca values measured by TIMS and ICP-DRC-MS with double-spike calibration in two samples (Ca ICP standard solution and digested NIST 1486 bone meal) coincided within the obtained precision. Although the applied isotope dilution with (43)Ca-(48)Ca double-spike compensates for time-dependent deviations of mass bias and allows achieving accurate results, this approach makes it necessary to measure an additional isotope pair, reducing the overall analysis time per isotope or increasing the total analysis time. Further development of external calibration by using a bracketing method would allow a wider use of ICP-DRC-MS for routine calcium isotopic measurements, but it still requires particular software or hardware improvements aimed at reliable control of environmental effects, which might influence signal stability in ICP-DRC-MS and serve as potential uncertainty sources in isotope ratio measurements.

Status of the TRIGA-LASER experiment

NASA Astrophysics Data System (ADS)

Gorges, C.; Kaufmann, S.; Geppert, Ch.; Krämer, J.; Sánchez, R.; Nörtershäuser, W.

2017-11-01

We report on the newly developed control system called TRITON and the new data acquisition called TILDA as well as on improved isotope shift measurements of the isotopes 40,42,44,48Ca in the 4 s 2S1/2 → 4 p 2P3/2 (D2) transition at the TRIGA-LASER experiment in Mainz using collinear laser spectroscopy. Well known isotope shift measurements in the 4 s 2S1/2 → 4 p 2P1/2 (D1) transition act as calibration points to reduce the uncertainties in the D2-line to provide reference values for the determination of nuclear charge radii and quadrupole moments of neutron rich calcium isotopes at COLLAPS.

Raman-Spektren der Hexathiohypodiphosphate des NH4, Mg, Ca, Sr und Ba

NASA Astrophysics Data System (ADS)

Pätzmann, Ulrich; Brockner, Wolfgang

1987-06-01

The title compounds have been prepared and their Raman spectra recorded. The observed frequencies of (NH4)4P2S6 and Mg2P2S6 are assigned on the basis of P2S64- units with D3d symmetry. The Raman spectra of the Calcium, Strontium and Barium compounds indicate symmetry splitting, therefore the P2S64- frequencies are assigned with C2h symmetry. This assignment is supported by the correlation D3d → C2h. It is concluded that Sr2P2S6 and Ba2P2S6 crystallize in the monoclinic modification II.

Add-On Antihypertensive Medications to Angiotensin-Aldosterone System Blockers in Diabetes: A Comparative Effectiveness Study.

PubMed

Schroeder, Emily B; Chonchol, Michel; Shetterly, Susan M; Powers, J David; Adams, John L; Schmittdiel, Julie A; Nichols, Gregory A; O'Connor, Patrick J; Steiner, John F

2018-05-07

In individuals with diabetes, the comparative effectiveness of add-on antihypertensive medications added to an angiotensin-converting enzyme inhibitor or angiotensin II receptor blocker on the risk of significant kidney events is unknown. We used an observational, multicenter cohort of 21,897 individuals with diabetes to compare individuals who added β -blockers, dihydropyridine calcium channel blockers, loop diuretics, or thiazide diuretics to angiotensin-converting enzyme inhibitors or angiotensin II receptor blockers. We examined the hazard of significant kidney events, cardiovascular events, and death using Cox proportional hazard models with propensity score weighting. The composite significant kidney event end point was defined as the first occurrence of a ≥30% decline in eGFR to an eGFR<60 ml/min per 1.73 m 2 , initiation of dialysis, or kidney transplant. The composite cardiovascular event end point was defined as the first occurrence of hospitalization for acute myocardial infarction, acute coronary syndrome, stroke, or congestive heart failure; coronary artery bypass grafting; or percutaneous coronary intervention, and it was only examined in those free of cardiovascular disease at baseline. Over a maximum of 5 years, there were 4707 significant kidney events, 1498 deaths, and 818 cardiovascular events. Compared with thiazide diuretics, hazard ratios for significant kidney events for β -blockers, calcium channel blockers, and loop diuretics were 0.81 (95% confidence interval, 0.74 to 0.89), 0.67 (95% confidence interval, 0.58 to 0.78), and 1.19 (95% confidence interval, 1.00 to 1.41), respectively. Compared with thiazide diuretics, hazard ratios of mortality for β -blockers, calcium channel blockers, and loop diuretics were 1.19 (95% confidence interval, 0.97 to 1.44), 0.73 (95% confidence interval, 0.52 to 1.03), and 1.67 (95% confidence interval, 1.31 to 2.13), respectively. Compared with thiazide diuretics, hazard ratios of cardiovascular events for β -blockers, calcium channel blockers, and loop diuretics compared with thiazide diuretics were 1.65 (95% confidence interval, 1.39 to 1.96), 1.05 (95% confidence interval, 0.80 to 1.39), and 1.55 (95% confidence interval, 1.05 to 2.27), respectively. Compared with thiazide diuretics, calcium channel blockers were associated with a lower risk of significant kidney events and a similar risk of cardiovascular events. Copyright © 2018 by the American Society of Nephrology.

Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide.

PubMed

Sazwi, Nordin Nur; Nalina, Thurairajah; Abdul Rahim, Zubaidah Haji

2013-12-11

Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined. Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay. Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective activity (r = 0.682). The betel quid has higher TPC, and antioxidant and cytoprotective activities than betel quid with calcium hydroxide. The quinic acid in betel quid may play an important role in the oral health protection.

Astronaut Bones: Stable Calcium Isotopes in Urine as a Biomarker of Bone Mineral Balance

NASA Astrophysics Data System (ADS)

Skulan, J.; Gordon, G. W.; Romaniello, S. J.; Anbar, A. D.; Smith, S. M.; Zwart, S.

2016-12-01

Bone loss is a common health concern, in conditions ranging from osteoporosis to cancer. Bone loss due to unloading is also an important health issue for astronauts. We demonstrate stable calcium isotopes, a tool developed in geochemistry, are capable of detecting real-time quantitative changes in net bone mineral balance (BMB) using serum and urine [1]. We validated this technique by comparing with DEXA and biomarker data in subjects during bed rest, a ground-based analog of space flight effects [2-4]. We now apply this tool to assess changes in astronauts' BMB before, during and after 4-6 month space missions. There is stable isotope fractionation asymmetry between bone formation and resorption. During bone formation there is a mass-dependent preference for "lighter" calcium isotopes to be removed from serum and incorporated into bone mineral. During bone resorption, there is no measurable isotopic discrimination between serum and bone. Hence, when bone formation rates exceed that of resorption, serum and urine become isotopically "heavy" due to the sequestration of "light" calcium in bone. Conversely, when bone resorption exceeds bone formation, serum and urine become isotopically "light" due to the release of the sequestered light calcium from bone. We measured Ca isotopes in urine of thirty International Space Station astronauts. Average Ca isotope values in astronauts' urine shift isotopically lighter during microgravity, consistent with negative net BMB. Within a month of return to Earth, astronauts returned to within error of their δ44Ca value prior to departure. Urine samples from astronauts testing bone loss countermeasures showed bisphosphonates provide a viable pharmacological countermeasure. Some, but not all, individuals appear able to resist bone loss through diet and intensive resistive exercise alone. This is a promising new technique for monitoring BMB in astronauts, and hopefully someday on the way to/from Mars, this also has important clinical applications for human health and terrestrial medicine [5]. REFERENCES [1] Morgan, J.L. et al (2011) Anal Chem 83, 6956-6962. [2] Skulan, J.L. et al. (2007) Clin Chem 53, 1155-1158. [3] Morgan, J.L. et al (2012) PNAS 109, 9989-9994. [4] Channon, M.B. et al (2015) Bone 77, 69-74. [5] Gordon, G.W. et al (2014) Leukemia 28, 2112-2115.

Bone mineralization is elevated and less heterogeneous in adults with type 2 diabetes and osteoarthritis compared to controls with osteoarthritis alone

PubMed Central

Pritchard, J.M.; Papaioannou, A.; Tomowich, C.; Giangregorio, L.M.; Atkinson, S.A.; Beattie, K.A.; Adachi, J.D.; DeBeer, J.; Winemaker, M.; Avram, V.; Schwarcz, H.P.

2016-01-01

Purpose The purpose of this study was to determine whether trabecular bone mineralization differed in adults with type 2 diabetes compared to adults without type 2 diabetes. Methods Proximal femur specimens were obtained following a total hip replacement procedure from men and women ≥65 years of age with and without type 2 diabetes. A scanning electron microscope was used for quantitative backscattered electron imaging (qBEI) analysis of trabecular bone samples from the femoral neck. Gray scale images (pixel size=5.6 μm2) were uploaded to ImageJ software and gray level (GL) values were converted to calcium concentrations (weight [wt] % calcium [Ca]) using data obtained with energy dispersive X-ray spectrometry. The following bone mineralization density distribution (BMDD) outcomes were collected: the weighted mean bone calcium concentration (CaMEAN), the most frequently occurring bone calcium concentration (CaPEAK) and mineralization heterogeneity (CaWIDTH). Differences between groups were assessed using the Student’s t-test for normally distributed data and Mann–Whitney U-test for non-normally distributed data. An alpha value of <0.05 was considered significant. Results Thirty-five Caucasian participants were recruited (mean [standard deviation, SD] age, 75.5 [6.5] years): 14 adults with type 2 diabetes (years since type 2 diabetes diagnosis, 13.5 [7.4] years) and 21 adults without type 2 diabetes. In the adults with type 2 diabetes, bone CaMEAN was 4.9% greater (20.36 [0.98] wt.% Ca versus 19.40 [1.07] wt.% Ca, p=0.015) and CaWIDTH was 9.4% lower (median [interquartile range] 3.55 [2.99–4.12] wt.% Ca versus 3.95 [0.71] wt.% Ca, p<0.001) compared to controls. There was no between-group difference in CaPEAK (21.12 [0.97] wt.% Ca for type 2 diabetes versus 20.44 [1.30] wt.% Ca for controls, p=0.121). Conclusion The combination of elevated mean calcium concentration in bone and lower mineralization heterogeneity in adults with type 2 diabetes may have deleterious effects on the biomechanical properties of bone. These microscopic alterations in bone mineralization, which may be mediated by suppressed bone remodeling, further elucidate higher fracture risk in adults with type 2 diabetes. PMID:23356988

Prophylactic intravenous calcium therapy for exchange blood transfusion in the newborn.

PubMed

Ogunlesi, Tinuade A; Lesi, Foluso Ea; Oduwole, Olabisi

2017-10-12

Exchange blood transfusion (EBT) is a form of whole blood transfusion in which the total blood volume is replaced within a few hours. In perinatal and neonatal medicine, EBT is most often used in the management of severe anaemia or severe hyperbilirubinaemia in the first week of life. Hypocalcaemia, one of the common morbidities associated with EBT, is thought to arise from the chelating effects of the citrate commonly used as an anticoagulant in the donor's blood. This disorder manifests with muscular and nervous irritability and cardiac arrhythmias. To determine whether the use of prophylactic calcium reduces the risk of hypocalcaemia-related morbidities and death among newborn infants receiving EBT. We used the standard search strategy of the Cochrane Neonatal Review group to search the Cochrane Central Register of Controlled Trials (CENTRAL 2016, Issue 5), MEDLINE via PubMed (1966 to 29 June 2016), Embase (1980 to 29 June 2016), and CINAHL (1982 to 29 June 2016). We also searched clinical trials databases, conference proceedings, and the reference lists of retrieved articles for randomised controlled trials and quasi-randomised trials. All randomised and quasi-randomised trials of prophylactic intravenous calcium in EBT for newborns. Two review authors independently assessed and extracted data on methods, participants, interventions, and outcomes (mean total and ionised serum calcium before and after EBT and the presence of adverse events such as hypoglycaemia, apnoea, cardiac arrest, and death immediately after EBT). We reported results as means difference (MD) with 95% confidence intervals (CI) for continuous outcomes and risk ratio (RR) and risk differences (RD) and 95% CIs for dichotomous outcomes. We assessed quality using the Cochrane 'Risk of bias' assessment tool and the GRADE system. We found only one quasi-randomised trial with 30 participants that met our inclusion criteria. In the small trial, total and ionised serum calcium levels were measured immediately before and immediately after EBT. All the participants were included in the final analysis and all the important outcomes were reported. Primary outcomesThere was one death in each group (RR 1.00, 95% CI 0.07 to 14.55; RD 0.00, 95% CI -0.18 to 0.18; participants = 30; studies = 1). The study did not report the presence of cardiac arrhythmias within one week of EBT and the number of infants with serum calcium levels (total less than 8 mg/dL (2 mmol/L) or ionised less than 4.4 mg/dL (1.1 mmol/L)).Pair-wise comparison of EBT with intravenous 10% calcium gluconate versus EBT without intravenous calcium (change from baseline) showed mean total serum calcium was raised in the intervention group compared to the control group (MD -0.46, 95% CI -0.81 to -0.11; participants = 30; studies = 1). Very low-quality evidence also indicated an increase in the levels of mean ionised serum calcium in the intervention group compared to the control group (MD -0.22, 95% CI -0.33 to -0.11; participants = 30; studies = 1). Secondary outcomesAdverse reactions to intravenous calcium therapy included cardiac arrest in one neonate in the intervention arm (RR 3.00, 95% CI 0.13 to 68.26; RD 0.07, 95% CI -0.10 to 0.23; participants = 30; studies = 1). There was apnoea and hypoglycaemia (RR 1.00, 95% CI 0.07 to 14.55; RD 0.00, 95% CI -0.18 to 0.18; participants = 30; studies = 1) in the two neonates who died. Data were not available for other major secondary outcomes such as the number of infants with reduced serum magnesium, reduced parathormone, increased calcitonin, presence of seizures, carpopedal spasm, jitteriness and prolonged QTc interval on electrocardiography within one week of EBT. Very low-quality data from one quasi-randomised controlled trial suggested that the mean serum total and ionised calcium increased in the study group but decreased in the control group immediately after EBT. However, the mean values of total and ionised calcium in both arms of studies remained within international reference ranges. Unfortunately, data were not available to assess the trend of total and ionised serum calcium to the end of the first week after EBT. Therefore, due to the very low quality of evidence available, it is difficult to support or reject the continual use of prophylactic intravenous calcium in newborn infants receiving EBT. Researchers are encouraged to conduct more robustly designed trials with larger numbers of participants, and particularly, addressing the pattern of differences based on gestational age of participants, type of anticoagulant used, and the volume of blood used.

Filling the gap in Ca input-output budgets in base-poor forest ecosystems: The contribution of non-crystalline phases evidenced by stable isotopic dilution

NASA Astrophysics Data System (ADS)

van der Heijden, Gregory; Legout, Arnaud; Mareschal, Louis; Ranger, Jacques; Dambrine, Etienne

2017-07-01

In terrestrial ecosystems, plant-available pools of magnesium and calcium are assumed to be stored in the soil as exchangeable cations adsorbed on the surface of mineral and/or organic particles. The pools of exchangeable magnesium and calcium are measured by ion-exchange soil extractions. These pools are sustained in the long term by the weathering of primary minerals in the soil and atmospheric inputs. This conceptual model is the base of input-output budgets from which soil acidification and the sustainability of soil chemical fertility is inferred. However, this model has been questioned by data from long-term forest ecosystem monitoring sites, particularly for calcium. Quantifying the contribution of atmospheric inputs, ion exchange and weathering of both primary, secondary and non-crystalline phases to tree nutrition in the short term is challenging. In this study, we developed and applied a novel isotopic dilution technique using the stable isotopes of magnesium and calcium to study the contribution of the different soil phases to soil solution chemistry in a very acidic soil. The labile pools of Mg and Ca in the soil (pools in equilibrium with the soil solution) were isotopically labeled by spraying a solution enriched in 26Mg and 44Ca on the soil. Labeled soil columns were then percolated with a dilute acid solution during a 3-month period and the isotopic dilution of the tracers was monitored in the leaching solution, in the exchangeable (2 sequential 1 mol L-1 ammonium acetate extractions) and non-crystalline (2 sequential soil digestions: oxalic acid followed by nitric acid) phases. Significant amounts of Mg and Ca isotope tracer were recovered in the non-crystalline soil phases. These phases represented from 5% to 25% and from 24% to 50%, respectively, of the Mg and Ca labile pools during the experiment. Our results show that non-crystalline phases act as both a source and a sink of calcium and magnesium in the soil, and contribute directly to soil solution chemistry on very short-term time scales. These phases are very abundant in acid soils and, in the present study, represent a substantial calcium pool (equivalent in size to the Ca exchangeable pool). The gradual isotopic dilution of Mg and Ca isotope ratios in the leaching solution during the experiment evidenced an input flux of Mg and Ca originating from a pool other than the labile pool. While the Mg input flux originated primarily from the weathering of primary minerals and secondarily from the non-crystalline phases, the Ca input flux originated primarily from the non-crystalline phases. Our results also show that the net calcium release flux from these phases may represent a significant source of calcium in forest ecosystems and actively contribute to compensating the depletion of Ca exchangeable pools in the soil. Non-crystalline phases therefore should be taken into account when computing input-output nutrient budgets and soil acid neutralizing capacity.

Validity of ambient levels of fine particles as surrogate for personal exposure to outdoor air pollution--results of the European EXPOLIS-EAS Study (Swiss Center Basel).

PubMed

Oglesby, L; Künzli, N; Röösli, M; Braun-Fahrländer, C; Mathys, P; Stern, W; Jantunen, M; Kousa, A

2000-07-01

To evaluate the validity of fixed-site fine particle levels as exposure surrogates in air pollution epidemiology, we considered four indicator groups: (1) PM2.5 total mass concentrations, (2) sulfur and potassium for regional air pollution, (3) lead and bromine for traffic-related particles, and (4) calcium for crustal particles. Using data from the European EXPOLIS (Air Pollution Exposure Distribution within Adult Urban Populations in Europe) study, we assessed the associations between 48-hr personal exposures and home outdoor levels of the indicators. Furthermore, within-city variability of fine particle levels was evaluated. Personal exposures to PM2.5 mass were not correlated to corresponding home outdoor levels (n = 44, rSpearman (Sp) = 0.07). In the group reporting neither relevant indoor sources nor relevant activities, personal exposures and home outdoor levels of sulfur were highly correlated (n = 40, rSp = 0.85). In contrast, the associations were weaker for traffic (Pb: n = 44, rSp = 0.53; Br: n = 44, rSp = 0.21) and crustal (Ca: n = 44, rSp = 0.12) indicators. This contrast is consistent with spatially homogeneous regional pollution and higher spatial variability of traffic and crustal indicators observed in Basel, Switzerland. We conclude that for regional air pollution, fixed-site fine particle levels are valid exposure surrogates. For source-specific exposures, however, fixed-site data are probably not the optimal measure. Still, in air pollution epidemiology, ambient PM2.5 levels may be more appropriate exposure estimates than total personal PM2.5 exposure, since the latter reflects a mixture of indoor and outdoor sources.

Validity of Ambient Levels of Fine Particles as Surrogate for Personal Exposure to Outdoor Air Pollution-Results of the European EXPOLIS-EAS Study (Swiss Center Basel).

PubMed

Oglesby, Lucy; Künzli, Nino; Röösli, Martin; Braun-Fahrländer, Charlotte; Mathys, Patrick; Stern, Willem; Jantunen, Matti; Kousa, Anu

2000-07-01

To evaluate the validity of fixed-site fine particle levels as exposure surrogates in air pollution epidemiology, we considered four indicator groups: (1) PM 25 total mass concentrations, (2) sulfur and potassium for regional air pollution, (3) lead and bromine for traffic-related particles, and (4) calcium for crustal particles. Using data from the European EXPOLIS (Air Pollution Exposure Distribution within Adult Urban Populations in Europe) study, we assessed the associations between 48-hr personal exposures and home outdoor levels of the indicators. Furthermore, within-city variability of fine particle levels was evaluated. Personal exposures to PM 2.5 mass were not correlated to corresponding home outdoor levels (n = 44, r S (S) =r o v ' Spearman (Sp) 0.07). In the group reporting neither relevant indoor sources nor relevant activities, personal exposures and home outdoor levels of sulfur were highly correlated (n = 40, r Sp = 0.85). In contrast, the associations were weaker for traffic (Pb: n = 44, r Sp = 0.53; Br: n = 44, r Sp = 0.21) and crustal (Ca: n = 44, r Sp = 0.12) indicators. This contrast is consistent with spatially homogeneous regional pollution and higher spatial variability of traffic and crustal indicators observed in Basel, Switzerland. We conclude that for regional air pollution, fixed-site fine particle levels are valid exposure surrogates. For source-specific exposures, however, fixed-site data are probably not the optimal measure. Still, in air pollution epidemiology, ambient PM 2.5 levels may be more appropriate exposure estimates than total personal PM 2.5 exposure, since the latter reflects a mixture of indoor and outdoor sources.

Effect of Silver Nitrate and Sodium Fluoride with Tri-Calcium Phosphate on Streptococcus mutans and Demineralised Dentine.

PubMed

Yu, Ollie Yiru; Zhao, Irene Shuping; Mei, May Lei; Lo, Edward Chin-Man; Chu, Chun-Hung

2018-04-25

This study investigated the effect of 25% silver nitrate (AgNO₃) and 5% sodium fluoride (NaF) varnish with functionalized tri-calcium phosphate (fTCP) on a Streptococcus mutans ( S. mutans ) biofilm and dentine caries lesion. Demineralised dentine specimens were treated with 25% AgNO₃ and 5% NaF + fTCP (Group 1), 25% AgNO₃ and 5% NaF (Group 2), 25% AgNO₃ (Group 3), or water (Group 4). The specimens were subjected to a S. mutans biofilm challenge after treatment. The biofilm was then studied via scanning electron microscopy (SEM), confocal laser scanning microscopy (CLSM), and colony forming units (CFU). The specimens were assessed by micro-computed tomography, X-ray diffraction (XRD), and Fourier transform infrared spectroscopy (FTIR). SEM and CLSM revealed less biofilm in Groups 1 to 3. The log 10 CFU of Groups 1 to 4 were 4.5 ± 0.7, 4.4 ± 0.9, 4.4 ± 0.9, and 6.7 ± 1.0, respectively (Groups 1, 2, 3 < 4, p < 0.001). The lesion depths of Groups 1 to 4 were 212.6 ± 20.1 µm, 280.8 ± 51.6 µm, 402.5 ± 61.7 µm, and 497.4 ± 67.2 µm, respectively (Groups 1 < 2 < 3 < 4, p < 0.001). XRD demonstrated silver chloride formation in Groups 1, 2, and 3. FTIR found the amide I: HPO₄ 2− values of the four groups were 0.22 ± 0.05, 0.25 ± 0.05, 0.41 ± 0.12, and 0.64 ± 0.14, respectively (Groups 1, 2 < 3 < 4; p < 0.001). In conclusion, this study revealed that AgNO₃ and NaF + fTCP reduced the damage of dentine caries by cariogenic biofilm.

[Assessment of energy and macronutrients supply in daily food rations of people exposed to hand transmitted vibrations].

PubMed

Zabłocka-Słowińska, Katarzyna; Limburska, Joanna; Prescha, Anna; Pieczyńska, Joanna; Tomczyk, Jarosław; Grajeta, Halina

2011-01-01

Occupational exposure of workers to mechanical hand transmitted vibrations may result in the development of nonspecific lesions. Balanced diet is one of factors that protect human organism against abnormalities resulting from occupational exposure. The aim of this study was to assess the supply of energy and macronutrients in daily food rations (DFR) of people exposed to hand transmitted vibration. Eighty workers, including 37 men (mean age 44.6 years) and 43 women (mean age 44 years) exposed to hand transmitted vibrations were recruited in this study. Of those, 72 people worked in crystal glassworks as glass cutters, 5 people were physiotherapists and 3 were woodcutters. For all workers, there was measured exposure to hand transmitted vibration. Nutritional status was assessed using 24-hour dietary recall; the procedure was repeated 3 times. The results of the nutritional assessment were compared with recommended daily allowances (RDA) for energy, protein, minerals and vitamins, total carbohydrates, total fat, saturated fatty acids (SFA), monounsaturated fatty acids (MUFA), polyunsaturated fatty acids (PUFA), cholesterol and dietary fibre. The average intake of energy in daily food rations of the women was too low while men received the appropriate amount of energy. Average protein intake by men and women was higher than the relevant RDA. The average amount of carbohydrates received by the surveyed women and men were too low, just as the consumption of PUFA, dietary fibre, potassium and calcium. We also found an excessive, average supply of total fat, MUFA, SFA, cholesterol and most of the vitamins with the DFR of the women and men. The nutrition in the group of workers exposed to hand transmitted vibration was found to be imbalanced due to excessive intakes of total fat, saturated fatty acids and cholesterol combined with insufficient consumption of carbohydrates, dietary fibres, potassium and calcium. The co-occurrence of vibration and imbalanced diet may increase the susceptibility of the subjects to cardiovascular and bone diseases.

Systematic review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia.

PubMed

Edafe, O; Antakia, R; Laskar, N; Uttley, L; Balasubramanian, S P

2014-03-01

Hypocalcaemia is common after thyroidectomy. Accurate prediction and appropriate management may help reduce morbidity and hospital stay. The aim of this study was to perform a systematic literature review and meta-analysis of predictors of post-thyroidectomy hypocalcaemia. A systematic search of PubMed, EMBASE and the Cochrane Library databases was undertaken, and the quality of manuscripts assessed using a modified Newcastle-Ottawa Scale. Some 115 observational studies were included. The median (i.q.r.) incidence of transient and permanent hypocalcaemia was 27 (19-38) and 1 (0-3) per cent respectively. Independent predictors of transient hypocalcaemia included levels of preoperative calcium, perioperative parathyroid hormone (PTH), preoperative 25-hydroxyvitamin D and postoperative magnesium. Clinical predictors included surgery for recurrent goitre and reoperation for bleeding. A calcium level lower than 1·88 mmol/l at 24 h after surgery, identification of fewer than two parathyroid glands (PTGs) at surgery, reoperation for bleeding, Graves' disease and heavier thyroid specimens were identified as independent predictors of permanent hypocalcaemia in multivariable analysis. Factors associated with transient hypocalcaemia in meta-analyses were inadvertent PTG excision (odds ratio (OR) 1·90, 95 per cent confidence interval 1·31 to 2·74), PTG autotransplantation (OR 2·03, 1·44 to 2·86), Graves' disease (OR 1·75, 1·34 to 2·28) and female sex (OR 2·28, 1·53 to 3·40). Perioperative PTH, preoperative vitamin D and postoperative changes in calcium are biochemical predictors of post-thyroidectomy hypocalcaemia. Clinical predictors include female sex, Graves' disease, need for parathyroid autotransplantation and inadvertent excision of PTGs. © 2014 BJS Society Ltd. Published by John Wiley & Sons Ltd.

Senna leaf extracts induced Ca(+2) homeostasis in a zoonotic tapeworm Hymenolepis diminuta.

PubMed

Roy, Saptarshi; Kundu, Suman; Lyndem, Larisha M

2016-10-01

Context Plants and plant products have been used in traditional medicine as anthelmintic agents in human and veterinary medicine. Three species of Senna plant, S. alata (L), S. alexandrina (M) and S. occidentalis (L.) Link (Fabaceae) have been shown to have a vermicidal/vermifugal effect on a zoonotic tapeworm Hymenolepis diminuta (Rudolphi) (Cyclophyllidean). Objective The present study validates the mode of action of these Senna plants on the parasite. The alcoholic leaf extract was determined to obtain information on the intracellular free calcium concentration level. Materials and methods Hymenolepis diminuta was maintained in Sprague-Dawley rat model for 2 months. Live parasites collected from infected rat intestine were exposed to 40 mg/mL concentration of each plant extracts prepared in phosphate buffer saline at 37 °C, till parasite gets paralyzed. The rate of efflux of calcium from the parasite tissue to the medium and the level of intracellular Ca(2+ )concentration were determined by an atomic absorption spectroscopy. Results This study revealed that exposure of the worms to the plant extract leads to disruption in intracellular calcium homeostasis. A significant increase (44.6% and 25%) of efflux in Ca(2+ )from the tissue to the incubated medium was observed. Senna alata showed high rate of efflux (5.32 mg/g) followed by S. alexandria and S. occidentalis (both 4.6 mg/g) compared with control (3.68 mg/g). Discussion and conclusion These results suggest that leaf extracts caused membrane permeability to Ca(2+ )after vacuolization of the tegument under stress and the extracts may contain compound that can be used as a chemotherapeutic agent.

Studies on physico-chemical and cooking characteristics of rice bean varieties grown in NE region of India.

PubMed

Bepary, Rejaul Hoque; Wadikar, D D; Neog, Seuji Borah; Patki, P E

2017-03-01

Rice bean ( Vigna umbellata ) is grown in South and Southeast Asia, and the bean has gained importance due to its nutritional strength in terms of dietary fiber, quality protein and minerals. In current study, the nutritional and functional components, cooking and thermo-gravimetric properties of eleven rice bean varieties from NE India were investigated. Results revealed that the major nutrients among the varieties ranged as follows: 54.21-60.49% carbohydrates, 15.64-21.60% protein, 1.22-2.3% fat, 5.53-6.56% crude fibre, 3.34-3.8% ash; while the functional, anti-nutritional factors and mineral were present as 1189.32-1645.8 mg gallic acid equivalent (GAE)/100 g polyphenols, 205.38-432.14 mg/100 g phytic acid, 23.14-34.12 mg/100 g oxalate, 690.7-1589.5 mg/100 g saponins, 49.90-158.17 μg/100 g hydrocyanide, 111.51-168 calcium, 5.50-10.44 zinc, 3.72-8.37 iron. Principal component analysis revealed that varieties with higher calcium, iron and ash content had lower cooking time, swelling ratio, and cooked grain hardness. It is also revealed that varieties with higher weight loss at sixth stage in thermogravimetric graph had lower carbohydrate and higher protein content. Nagadal variety had higher fat, potassium, magnesium, calcium, sodium, iron, copper and chromium content and better cooking quality as compared to the other varieties. The study revealed that Nagadal variety was superior to other varieties with respect to mineral content, cooking and thermal properties and hence have better potential in the development of value added products.

Magnesium and calcium sulfate stabilities and the water budget of Mars

USGS Publications Warehouse

Chou, I.-Ming; Seal, R.R.

2007-01-01

Magnesium sulfate probably plays a dominant role in the water cycle of Mars away from the polar ice caps through hydration and dehydration reactions. This prominence is due to its abundance, its occurrence in numerous hydration states, and its ability to hydrate and dehydrate rapidly. New experimental studies on the metastable reaction between hexahydrite (MgSO4??6H2O) and starkeyite (MgSO4-4H2O) as a function of temperature and relative humidity, supplemented by recent investigations of the stable reaction between epsomite (MgSO4??7H2O) and hexahydrite and by phase equilibrium calculations, suggest that the most important magnesium sulfate phases involved in the Martian water cycle are MgSO4??11 H2O, epsomite, starkeyite, and possibly kieserite (MgSO4??H2O). Hexahydrite is not predicted to be stable on the surface of Mars. During diurnal variations in temperature and relative humidity, 1 kg of MgSO4 can release or remove from the atmosphere 1.5 kg of H2O by cycling between kieserite and MgSO4??11 H2O. Despite subequal abundances of calcium sulfate, calcium sulfates are not likely to be important in the water cycle of the planet because of sluggish rates of hydration and dehydration and a more limited range of H2O concentrations per kilogram of CaSO4 (0.00 to 0.26 kg kg-1). Modern or recent erosion on Mars attributed to liquid water may be due to the dehydration Of MgSO4??11 H2O because of the inferred abundance and likelihood of occurrence of this phase and its limited stability relative to known variations in temperature and relative humidity.

Serum magnesium, phosphorus, and calcium levels and subclinical calcific aortic valve disease: A population-based study.

PubMed

Hisamatsu, Takashi; Miura, Katsuyuki; Fujiyoshi, Akira; Kadota, Aya; Miyagawa, Naoko; Satoh, Atsushi; Zaid, Maryam; Yamamoto, Takashi; Horie, Minoru; Ueshima, Hirotsugu

2018-06-01

Calcific aortic valve disease (CAVD) is the most common valve disease. Although micronutrients are known to contribute to cardiovascular disease, the relationship with CAVD remains poorly evaluated. We examined the association of serum levels of magnesium, phosphorus, and calcium with prevalence, incidence, and progression of aortic valve calcification (AVC). We conducted a prospective study in a population-based sample of Japanese men aged 40-79 years without known cardiovascular disease and chronic kidney disease at baseline, and quantified AVC from serial computed tomographic images with the Agatston method. Of 938 participants at baseline (mean age, 63.7 ± 9.9 years), AVC prevalence was observed in 173 (18.4%). Of 596 participants without baseline AVC at follow-up (median duration, 5.1 years), AVC incidence was observed in 138 (23.2%). After adjustment for demographics, behaviors and cardiovascular risk factors, relative risks (95% confidence intervals) in the highest versus lowest categories of serum magnesium, phosphorus, and calcium were 0.62 (0.44-0.86), 1.45 (1.02-2.04), and 1.43 (0.95-2.15), respectively, for AVC prevalence and 0.62 (0.42-0.92), 1.93 (1.28-2.91), and 1.09 (0.77-1.55), respectively, for AVC incidence. Their linear trends of serum magnesium and phosphorus were also all statistically significant. Of 131 participants with baseline AVC, there was no association of any serum micronutrients with AVC progression. Serum magnesium was inversely associated, while serum phosphorus was positively associated with AVC prevalence and incidence, suggesting that these serum micronutrients may be potential candidates for risk prediction or prevention of CAVD, and warranting further studies. Copyright © 2018 Elsevier B.V. All rights reserved.

Effects of draught load exercise and training on calcium homeostasis in horses.

PubMed

Vervuert, I; Coenen, M; Zamhöfer, J

2005-01-01

This study was conducted to investigate the effects of draught load exercise on calcium (Ca) homeostasis in young horses. Five 2-year-old untrained Standardbred horses were studied in a 4-month training programme. All exercise workouts were performed on a treadmill at a 6% incline and with a constant draught load of 40 kg (0.44 kN). The training programme started with a standardized exercise test (SET 1; six incremental steps of 5 min duration each, first step 1.38 m/s, stepwise increase by 0.56 m/s). A training programme was then initiated which consisted of low-speed exercise sessions (LSE; constant velocity at 1.67 m/s for 60 min, 48 training sessions in total). After the 16th and 48th LSE sessions, SETs (SET 2: middle of training period, SET 3: finishing training period) were performed again under the identical test protocol of SET 1. Blood samples for blood lactate, plasma total Ca, blood ionized calcium (Ca(2+)), blood pH, plasma inorganic phosphorus (P(i)) and plasma intact parathyroid hormone (PTH) were collected before, during and after SETs, and before and after the first, 16th, 32nd and 48th LSE sessions. During SETs there was a decrease in ionized Ca(2+) and a rise in lactate, P(i) and intact PTH. The LSEs resulted in an increase in pH and P(i), whereas lactate, ionized Ca(2+), total Ca and intact PTH were not affected. No changes in Ca metabolism were detected in the course of training. Results of this study suggest that the type of exercise influences Ca homeostasis and intact PTH response, but that these effects are not influenced in the course of the training period.

Magnesium stable isotope ecology using mammal tooth enamel

NASA Astrophysics Data System (ADS)

Martin, Jeremy E.; Vance, Derek; Balter, Vincent

2015-01-01

Geochemical inferences on ancient diet using bone and enamel apatite rely mainly on carbon isotope ratios (δ13C) and to a lesser extent on strontium/calcium (Sr/Ca) and barium/calcium (Ba/Ca) elemental ratios. Recent developments in nontraditional stable isotopes provide an unprecedented opportunity to use additional paleodietary proxies to disentangle complex diets such as omnivory. Of particular relevance for paleodietary reconstruction are metals present in large quantity in bone and enamel apatite, providing that biologically mediated fractionation processes are constrained. Calcium isotope ratios (δ44Ca) meet these criteria but exhibit complex ecological patterning. Stable magnesium isotope ratios (δ26Mg) also meet these criteria but a comprehensive understanding of its variability awaits new isotopic data. Here, 11 extant mammal species of known ecology from a single locality in equatorial Africa were sampled for tooth enamel and, together with vegetation and feces, analyzed for δ26Mg, δ13C, Sr/Ca, and Ba/Ca ratios. The results demonstrate that δ26Mg incorporated in tooth enamel becomes heavier from strict herbivores to omnivores/faunivores. Using data from experimentally raised sheep, we suggest that this 26Mg enrichment up the trophic chain is due to a 26Mg enrichment in muscle relative to bone. Notably, it is possible to distinguish omnivores from herbivores, using δ26Mg coupled to Ba/Ca ratios. The potential effects of metabolic and dietary changes on the enamel δ26Mg composition remain to be explored but, in the future, multiproxy approaches would permit a substantial refinement of dietary behaviors or enable accurate trophic reconstruction despite specimen-limited sampling, as is often the case for fossil assemblages.

Multi-omics Analysis of Serum Samples Demonstrates Reprogramming of Organ Functions Via Systemic Calcium Mobilization and Platelet Activation in Metastatic Melanoma*

PubMed Central

Muqaku, Besnik; Eisinger, Martin; Meier, Samuel M.; Tahir, Ammar; Pukrop, Tobias; Haferkamp, Sebastian; Slany, Astrid; Reichle, Albrecht

2017-01-01

Pathophysiologies of cancer-associated syndromes such as cachexia are poorly understood and no routine biomarkers have been established, yet. Using shotgun proteomics, known marker molecules including PMEL, CRP, SAA, and CSPG4 were found deregulated in patients with metastatic melanoma. Targeted analysis of 58 selected proteins with multiple reaction monitoring was applied for independent data verification. In three patients, two of which suffered from cachexia, a tissue damage signature was determined, consisting of nine proteins, PLTP, CD14, TIMP1, S10A8, S10A9, GP1BA, PTPRJ, CD44, and C4A, as well as increased levels of glycine and asparagine, and decreased levels of polyunsaturated phosphatidylcholine concentrations, as determined by targeted metabolomics. Remarkably, these molecules are known to be involved in key processes of cancer cachexia. Based on these results, we propose a model how metastatic melanoma may lead to reprogramming of organ functions via formation of platelet activating factors from long-chain polyunsaturated phosphatidylcholines under oxidative conditions and via systemic induction of intracellular calcium mobilization. Calcium mobilization in platelets was demonstrated to alter levels of several of these marker molecules. Additionally, platelets from melanoma patients proved to be in a rather exhausted state, and platelet-derived eicosanoids implicated in tumor growth were found massively increased in blood from three melanoma patients. Platelets were thus identified as important source of serum protein and lipid alterations in late stage melanoma patients. As a result, the proposed model describes the crosstalk between lipolysis of fat tissue and muscle wasting mediated by oxidative stress, resulting in the metabolic deregulations characteristic for cachexia. PMID:27879288

Meningitic Escherichia coli K1 penetration and neutrophil transmigration across the blood-brain barrier are modulated by alpha7 nicotinic receptor.

PubMed

Chi, Feng; Wang, Lin; Zheng, Xueye; Wu, Chun-Hua; Jong, Ambrose; Sheard, Michael A; Shi, Wei; Huang, Sheng-He

2011-01-01

Alpha7 nicotinic acetylcholine receptor (nAChR), an essential regulator of inflammation, is abundantly expressed in hippocampal neurons, which are vulnerable to bacterial meningitis. However, it is unknown whether α7 nAChR contributes to the regulation of these events. In this report, an aggravating role of α7 nAChR in host defense against meningitic E. coli infection was demonstrated by using α7-deficient (α7(-/-)) mouse brain microvascular endothelial cells (BMEC) and animal model systems. As shown in our in vitro and in vivo studies, E. coli K1 invasion and polymorphonuclear neutrophil (PMN) transmigration across the blood-brain barrier (BBB) were significantly reduced in α7(-/-) BMEC and α7(-/-) mice. Stimulation by nicotine was abolished in the α7(-/-) cells and animals. The same blocking effect was achieved by methyllycaconitine (α7 antagonist). The tight junction molecules occludin and ZO-1 were significantly reduced in the brain cortex of wildtype mice infected with E. coli and treated with nicotine, compared to α7(-/-) cells and animals. Decreased neuronal injury in the hippocampal dentate gyrus was observed in α7(-/-) mice with meningitis. Proinflammatory cytokines (IL-1β, IL-6, TNFα, MCP-1, MIP-1alpha, and RANTES) and adhesion molecules (CD44 and ICAM-1) were significantly reduced in the cerebrospinal fluids of the α7(-/-) mice with E. coli meningitis. Furthermore, α7 nAChR is the major calcium channel for nicotine- and E. coli K1-increased intracellular calcium concentrations of mouse BMEC. Taken together, our data suggest that α7 nAChR plays a detrimental role in the host defense against meningitic infection by modulation of pathogen invasion, PMN recruitment, calcium signaling and neuronal inflammation.

Meningitic Escherichia coli K1 Penetration and Neutrophil Transmigration Across the Blood–Brain Barrier are Modulated by Alpha7 Nicotinic Receptor

PubMed Central

Zheng, Xueye; Wu, Chun-Hua; Jong, Ambrose; Sheard, Michael A.; Shi, Wei; Huang, Sheng-He

2011-01-01

Alpha7 nicotinic acetylcholine receptor (nAChR), an essential regulator of inflammation, is abundantly expressed in hippocampal neurons, which are vulnerable to bacterial meningitis. However, it is unknown whether α7 nAChR contributes to the regulation of these events. In this report, an aggravating role of α7 nAChR in host defense against meningitic E. coli infection was demonstrated by using α7-deficient (α7-/-) mouse brain microvascular endothelial cells (BMEC) and animal model systems. As shown in our in vitro and in vivo studies, E. coli K1 invasion and polymorphonuclear neutrophil (PMN) transmigration across the blood-brain barrier (BBB) were significantly reduced in α7-/- BMEC and α7-/- mice. Stimulation by nicotine was abolished in the α7-/- cells and animals. The same blocking effect was achieved by methyllycaconitine (α7 antagonist). The tight junction molecules occludin and ZO-1 were significantly reduced in the brain cortex of wildtype mice infected with E. coli and treated with nicotine, compared to α7-/- cells and animals. Decreased neuronal injury in the hippocampal dentate gyrus was observed in α7-/- mice with meningitis. Proinflammatory cytokines (IL-1β, IL-6, TNFα, MCP-1, MIP-1alpha, and RANTES) and adhesion molecules (CD44 and ICAM-1) were significantly reduced in the cerebrospinal fluids of the α7-/- mice with E. coli meningitis. Furthermore, α7 nAChR is the major calcium channel for nicotine- and E. coli K1-increased intracellular calcium concentrations of mouse BMEC. Taken together, our data suggest that α7 nAChR plays a detrimental role in the host defense against meningitic infection by modulation of pathogen invasion, PMN recruitment, calcium signaling and neuronal inflammation. PMID:21966399

A role for exosomes in the constitutive and stimulus-induced ectodomain cleavage of L1 and CD44.

PubMed

Stoeck, Alexander; Keller, Sascha; Riedle, Svenja; Sanderson, Michael P; Runz, Steffen; Le Naour, Francois; Gutwein, Paul; Ludwig, Andreas; Rubinstein, Eric; Altevogt, Peter

2006-02-01

Ectodomain shedding is a proteolytic mechanism by which transmembrane molecules are converted into a soluble form. Cleavage is mediated by metalloproteases and proceeds in a constitutive or inducible fashion. Although believed to be a cell-surface event, there is increasing evidence that cleavage can take place in intracellular compartments. However, it is unknown how cleaved soluble molecules get access to the extracellular space. By analysing L1 (CD171) and CD44 in ovarian carcinoma cells, we show in the present paper that the cleavage induced by ionomycin, APMA (4-aminophenylmercuric acetate) or MCD (methyl-beta-cyclodextrin) is initiated in an endosomal compartment that is subsequently released in the form of exosomes. Calcium influx augmented the release of exosomes containing functionally active forms of ADAM10 (a disintegrin and metalloprotease 10) and ADAM17 [TACE (tumour necrosis factor a-converting enzyme)] as well as CD44 and L1 cytoplasmic cleavage fragments. Cleavage could also proceed in released exosomes, but only depletion of ADAM10 by small interfering RNA blocked cleavage under constitutive and induced conditions. In contrast, cleavage of L1 in response to PMA occurred at the cell surface and was mediated by ADAM17. We conclude that different ADAMs are involved in distinct cellular compartments and that ADAM10 is responsible for shedding in vesicles. Our findings open up the possibility that exosomes serve as a platform for ectodomain shedding and as a vehicle for the cellular export of soluble molecules.

Marine Carbonate Component in the Mantle Beneath the Southeastern Tibetan Plateau: Evidence From Magnesium and Calcium Isotopes

NASA Astrophysics Data System (ADS)

Liu, Fang; Li, Xin; Wang, Guiqin; Liu, Yufei; Zhu, Hongli; Kang, Jinting; Huang, Fang; Sun, Weidong; Xia, Xiaoping; Zhang, Zhaofeng

2017-12-01

Tracing and identifying recycled carbonates is a key issue to reconstruct the deep carbon cycle. To better understand carbonate subduction and recycling beneath the southeastern Tibetan Plateau, high-K cal-alkaline volcanic rocks including trachy-basalts and trachy-andesites from Tengchong were studied using Mg and Ca isotopes. The low δ26Mg (-0.31 ± 0.03‰ to -0.38 ± 0.03‰) and δ44/40Ca (0.67 ± 0.07‰ to 0.80 ± 0.04‰) values of these volcanic rocks compared to those of the mantle (-0.25 ± 0.07‰ and 0.94 ± 0.05‰, respectively) indicate the incorporation of isotopically light materials into the mantle source, which may be carbonate-bearing sediments with low δ26Mg and δ44/40Ca values. In addition, no correlations of δ26Mg and δ44/40Ca with either SiO2 contents or trace element abundance ratios (e.g., Sm/Yb and Ba/Y) were observed, suggesting that limited Mg and Ca isotopic fractionation occurred during cal-alkaline magmatic differentiation. A binary mixing model using Mg-Ca isotopes shows that 5-8% carbonates dominated primarily by dolostone were recycled back into the mantle. Since Tengchong volcanism is still active and probably related to ongoing plate tectonic movement, we propose that the recycled carbonates are derived from oceanic crust related to the ongoing subduction of the Indian plate.

Influence of Si substitution on the reactivity of α-tricalcium phosphate.

PubMed

Motisuke, Mariana; Mestres, Gemma; Renó, Caroline O; Carrodeguas, Raúl G; Zavaglia, Cecília A C; Ginebra, Maria-Pau

2017-06-01

Silicon substituted calcium phosphates have been widely studied over the last ten years due to their enhanced osteogenic properties. Notwithstanding, the role of silicon on α-TCP reactivity is not clear yet. Therefore, the aim of this work was to evaluate the reactivity and the properties of Si-α-TCP in comparison to α-TCP. Precursor powders have similar properties regarding purity, particle size distribution and specific surface area, which allowed a better comparison of the Si effects on their reactivity and cements properties. Both Si-α-TCP and α-TCP hydrolyzed to a calcium-deficient hydroxyapatite when mixed with water but their conversion rates were different. Si-α-TCP exhibited a slower setting rate than α-TCP, i.e. k SSA for Si-TCP (0.021g·m -2 ·h -1 ) was almost four times lower than for α-TCP (0.072g·m -2 ·h -1 ). On the other hand, the compressive strength of the CPC resulting from fully reacted Si-α-TCP was significantly higher (12.80±0.38MPa) than that of α-TCP (11.44±0.54MPa), due to the smaller size of the entangled precipitated apatite crystals. Copyright © 2017. Published by Elsevier B.V.

Nutritional status of four species of giant land snails in Nigeria

PubMed Central

Fagbuaro, O.; Oso, J.A.; Edward, J.B.; Ogunleye, R.F.

2006-01-01

Four species of African giant land snails (Archachatina marginata (ovum) Pfeiffer, Archachatina marginata (saturalis) Philippi, Achatina achatina and Limicolaria spp.) were assessed for their proximate and mineral compositions aimed at establishing their nutritive values on wet weight basis. Analysis of muscle revealed that composition of crude protein varied from 18.66%±0.57% in Limicolaria spp. and 20.56%±0.05% in Archachatina marginata (ovum) Pfeiffer; moisture content was 76.56%±0.04% in Archachatina marginata (ovum) Pfeiffer and 78.68%±0.68% in Limicolaria spp. and ash was 1.34%±0.02% in Achatina achatina and 1.44%±0.01% in Archachatina marginata (ovum) Pfeiffer. These values were statistically different from each other (P<0.05). Carbohydrate and fat content were generally low. Crude fibre was not detected in any of the species. The concentrations of zinc, iron, manganese, magnesium, calcium, phosphorus, sulphur, potassium and sodium in the flesh of the snails were determined. Values of iron, magnesium, calcium, phosphorus, potassium and sodium were consistently high while cobalt, copper and lead were not detected. Snails complement the required trace and minor elements needed for proper growth and development in human being, so it is recommended for regular consumption. PMID:16909467

Climate variability during the deglaciation and Holocene in a high-altitude alpine lake deduced from the sedimentary record from Laguna Seca, Sierra Nevada, southern Iberian Peninsula

NASA Astrophysics Data System (ADS)

Camuera, Jon; Jiménez-Moreno, Gonzalo; José Ramos-Román, María; García-Alix, Antonio; Jiménez-Espejo, Francisco; Anderson, R. Scott

2017-04-01

High-resolution X-ray fluorescence (XRF), magnetic susceptibility (MS), color and lithological analyses have been carried out on a 3.6 m-long sediment core from Laguna Seca, a high-elevation dry lake from Sierra Nevada mountain range, southern Spain. This is the longest sedimentary record retrieved from an alpine lake in southern Iberian Peninsula. Besides, alpine lakes are very sensitive environments to climate changes and previous studies showed that Laguna Seca could provide an excellent record to identify millennial-scale climate variations during deglaciation and the whole Holocene. XRF analyses, in particular high calcium and low K/Ca ratios, show aridity phases, very well represented during Last Glacial Maximum (LGM) and the Younger Dryas (YD). Arid events are also shown at ca. 8.1 ka BP, ca. 4.4 ka BP and the latest Holocene. On the other hand, negative values in calcium and positive values in K/Ca appear in the Bølling-Allerød (BA) and during the early Holocene until ca. 6 ka BP, indicating more humidity and higher run-off. A progressive aridification trend is also observed in the Holocene, changing from more humid conditions during the early Holocene to more aridity during the late Holocene.

Artificial Niches for Stromal Stem Cells as a Potential Instrument for the Design of the Surface of Biomimetic Osteogenic Materials

NASA Astrophysics Data System (ADS)

Khlusov, I. A.; Khlusova, M. Yu.; Pichugin, V. F.; Sharkeev, Yu. P.; Legostaeva, E. V.

2014-02-01

A relationship between the topography of rough calcium phosphate surfaces having osteogenic niche-reliefs and the electrostatic potential of these surfaces as a possible instrument to control stromal stem cells has been investigated. The in vitro culture of human lung prenatal stromal cells on nanostructured/ultrafine-grained VT1.0 titanium alloy plates with bilateral rough calcium phosphate (CaP) microarc coating was used. It was established that the amplitude of the electret CaP surface potential linearly increased with increasing area of valleys (sockets), and the negative charge is formed on the socket surface. The area of alkaline phosphatase staining (the marker of osteoblast maturation and differentiation) of adherent CD34- CD44+ cells increases linearly with increasing area of artificial microterritory (socket) of the CaP surface occupied with each cell. The negative electret potential in valleys (sockets) of microarc CaP coatings can be the physical mechanism mediating the influence of the surface topography on osteogenic maturation and differentiation of cells in vitro. This mechanism can be called "niche-potential" and can be used as an instrument for biomimetic modification of smooth CaP surfaces to strengthen their integration with the bone tissue.

Degradable biocomposite of nano calcium-deficient hydroxyapatite-multi(amino acid) copolymer

PubMed Central

Li, Hong; Gong, Min; Yang, Aiping; Ma, Jian; Li, Xiangde; Yan, Yonggang

2012-01-01

Background and methods A nano calcium-deficient hydroxyapatite (n-CDHA)-multi(amino acid) copolymer (MAC) composite bone substitute biomaterial was prepared using an in situ polymerization method. The composition, structure, and compressive strength of the composite was characterized, and the in vitro degradability in phosphate-buffered solution and preliminary cell responses to the composite were investigated. Results The composite comprised n-CDHA and an amide linkage copolymer. The compressive strength of the composite was in the range of 88–129 MPa, varying with the amount of n-CDHA in the MAC (ranging from 10 wt% to 50 wt%). Weight loss from the composite increased (from 32.2 wt% to 44.3 wt%) with increasing n-CDHA content (from 10 wt% to 40 wt%) in the MAC after the composite was soaked in phosphate-buffered solution for 12 weeks. The pH of the soaking medium varied from 6.9 to 7.5. MG-63 cells with an osteogenic phenotype were well adhered and spread on the composite surface. Viability and differentiation increased with time, indicating that the composite had no negative effects on MG-63 cells. Conclusion The n-CDHA-MAC composite had good cytocompatibility and has potential to be used as a bone substitute. PMID:22457591

Calcium Isotope Fractionation during Carbonate Weathering in the Northern Guangdong, South China

NASA Astrophysics Data System (ADS)

Liu, F.; Mao, G.; Wei, G.; Zhang, Z.

2017-12-01

CO2 is consumed during the weathering of carbonates, whereas carbonates are precipitated rapidly in the oceans, which are pivotal to modulate atmospheric CO2, oceanic pH and climate. Calcium carbonate in limestone is one of the largest reservoirs of carbon at the Earth's surface, so calcium is an important element that links the lithosphere, hydrosphere, biosphere, and the atmosphere. Compared with silicate rocks, carbonate rocks have more rapid rates of physical and chemical erosions, so the carbonate weathering will respond more quickly to the climatic changes. In the southeast of China, enormous of carbonate rocks are widely distributed. Due to the influence of the subtropical monsoon climate, the rocks experienced strong chemical weathering and pedogenic process, resulting in red weathering crust of carbonate rocks. This type of weathering crust is geochemistry-sensitive and ecology-vulnerable, which can provide important insights into the recycle of supergene geochemistry in the karst areas. In this study, we report calcium isotopic compositions of saprolites from a weathering profile developed on argillaceous carbonate rocks in northern Guangdong, South China. The acid-leachable fraction, which was extracted by 1N hydrochloride acid, showed limited variation of δ44/40Ca(NIST 915a) spanning from 0.55 ± 0.06‰ (2SD) to 0.72 ± 0.05‰ (2SD) despite CaO content ranging from 0.01 wt.% to 45.7 wt.%, implying that Ca isotope didn't fractionate much which may due to the congruent dissolution of limestone minerals. In contrast, radiogenic 87Sr/86Sr ratios of the whole rocks changed with depth from 0.710086 ± 6 (2SE) at the base rock to 0.722164± 8 (2SE) at the top-soil, which are possibly attributed to the mixing effect between carbonate and silicate fractions. Sr is an analogue for Ca due to its similar ionic size and charge; however, these two systems can differ in certain respects. The coupled study of Ca and Sr will be helpful to verify sources of Ca and the global Ca and C cycles.

Ryanodine receptors regulate arterial diameter and wall [Ca2+] in cerebral arteries of rat via Ca2+-dependent K+ channels

PubMed Central

Knot, Harm J; Standen, Nicholas B; Nelson, Mark T

1998-01-01

The effects of inhibitors of ryanodine-sensitive calcium release (RyR) channels in the sarcoplasmic reticulum (SR) and Ca2+-dependent potassium (KCa) channels on the membrane potential, intracellular [Ca2+], and diameters of small pressurized (60 mmHg) cerebral arteries (100–200 μm) were studied using digital fluorescence video imaging of arterial diameter and wall [Ca2+], combined with microelectrode measurements of arterial membrane potential. Ryanodine (10 μm), an inhibitor of RyR channels, depolarized by 9 mV, increased intracellular [Ca2+] by 46 nm and constricted pressurized (to 60 mmHg) arteries with myogenic tone by 44 μm (∼22 %). Iberiotoxin (100 nm), a blocker of KCa channels, under the same conditions, depolarized the arteries by 10 mV, increased arterial wall calcium by 51 nm, and constricted by 37 μm (∼19 %). The effects of ryanodine and iberiotoxin were not additive and were blocked by inhibitors of voltage-dependent Ca2+ channels. Caffeine (10 mm), an activator of RyR channels, transiently increased arterial wall [Ca2+] by 136 ± 9 nm in control arteries and by 158 ± 12 nm in the presence of iberiotoxin. Caffeine was relatively ineffective in the presence of ryanodine, increasing [calcium] by 18 ± 5 nm. In the presence of blockers of voltage-dependent Ca2+ channels (nimodipine, diltiazem), ryanodine and inhibitors of the SR calcium ATPase (thapsigargin, cyclopiazonic acid) were without effect on arterial wall [Ca2+] and diameter. These results suggest that local Ca2+ release originating from RyR channels (Ca2+ sparks) in the SR of arterial smooth muscle regulates myogenic tone in cerebral arteries solely through activation of KCa channels, which regulate membrane potential through tonic hyperpolarization, thus limiting Ca2+ entry through L-type voltage-dependent Ca2+ channels. KCa channels therefore act as a negative feedback control element regulating arterial diameter through a reduction in global intracellular free [Ca2+]. PMID:9490841

Effects of Recombinant Human Lactoferrin on Osteoblast Growth and Bone Status in Piglets.

PubMed

Li, Qiuling; Zhao, Jie; Hu, Wenping; Wang, Jianwu; Yu, Tian; Dai, Yunping; Li, Ning

2018-04-03

Lactoferrin (LF), an ~80 kDa iron-binding glycoprotein, modulates many biological effects, including antimicrobial and immunomodulatory activities. Recently, it was shown that LF also regulates bone cell activity, suggesting its therapeutic effect on postmenopausal bone loss. However, a minimal amount is known regarding the effects of recombinant human LF (rhLF) supplementation on bone status in young healthy infants. We found osteoblast cell differentiation was significantly promoted in vitro. Furthermore, treatment of human osteoblast cells with rhLF rapidly induced phosphorylation of p44/p42 mitogen-activated protein kinase (p44/p42 MAPK, ERK1/2). In order to investigate the effects of rhLF on bone status in vivo, we used a piglet model, which is a useful model for human infants. Piglets were supplemented with rhLF milk for 30 days. Bone formation markers, Serum calcium concentration, bone mineral density (BMD), bone mineral content (BMC), tibia bone strength, and the overall metabolite profile analysis showed that rhLF was advantageous to the bone growth in piglets. These findings suggest that rhLF supplementation benefits neonate bone health by modulating bone formation.

Dual pH/redox responsive and CD44 receptor targeting hybrid nano-chrysalis based on new oligosaccharides of hyaluronan conjugates.

PubMed

Chen, Daquan; Dong, Xue; Qi, Mengjiao; Song, Xiaoyan; Sun, Jingfang

2017-02-10

A smart hybrid microenvironment-mediated dual pH/redox-responsive polymeric nanoparticles combined with inorganic calcium phosphate (CaP) was fabricated, which we term as armored nano-chrysalis inspired by butterfly pupa. The nano-chrysalis has an inner core composed of specially designed oligosaccharides of hyaluronan (oHA) targeting CD44 receptor. The inner core has two functions, i.e., the dual pH/redox responsive polymeric conjugate and the fluorescent curcumin-prodrug function. The prepared nano-chrysalis possessed a smaller size (102.5±4.6nm) than the unarmored nano-chrysalis (122.5±6.6nm). Interestingly, while the nano-chrysalis were stable under pH 7.4, when incubated under the tumor acidic conditions (pH 6.5) the outer CaP armor would dissolve in a pH-dependent, sustained manner. Moreover, nano-chrysalis was demonstrated to present the most effective antitumor efficacy than other formulations. This study provides a promising smart nano-carrier platform to enhance the stability, decrease the side effects, and improve the therapeutic efficacy of anticancer drugs. Copyright © 2016 Elsevier Ltd. All rights reserved.

Synthesis and Evaluation of Orexin-1 Receptor Antagonists with Improved Solubility and CNS Permeability.

PubMed

Perrey, David A; Decker, Ann M; Zhang, Yanan

2018-03-21

Orexins are hypothalamic neuropeptides playing important roles in many functions including the motivation of addictive behaviors. Blockade of the orexin-1 receptor has been suggested as a potential strategy for the treatment of drug addiction. We have previously reported OX 1 receptor antagonists based on the tetrahydroisoquinoline scaffold with excellent OX 1 potency and selectivity; however, these compounds had high lipophilicity (clogP > 5) and low to moderate solubility. In an effort to improve their properties, we have designed and synthesized a series of analogues where the 7-position substituents known to favor OX 1 potency and selectivity were retained, and groups of different nature were introduced at the 1-position where substitution was generally tolerated as demonstrated in previous studies. Compound 44 with lower lipophilicity (clogP = 3.07) displayed excellent OX 1 potency ( K e = 5.7 nM) and selectivity (>1,760-fold over OX 2 ) in calcium mobilization assays. In preliminary ADME studies, 44 showed excellent kinetic solubility (>200 μM), good CNS permeability ( P app = 14.7 × 10 -6 cm/sec in MDCK assay), and low drug efflux (efflux ratio = 3.3).

Soil Fertility and Radicular System Depth of Sand Coastal Plain Forest

NASA Astrophysics Data System (ADS)

Casagrande, José Carlos; Akemi Sato, Claudia; Reis-Duarte, Rose Mary; Soares, Marcio Roberto; Sérgio Galvão Bueno, Mário

2010-05-01

The sand coastal plain vegetation (Restinga Forest) is a type of ecosystem associated with the Atlantic Forest constituted of mosaics, which occur in areas of great ecological diversity. This vegetation is currently assigned as edaphic communities. In this study we present data on soil fertility in different vegetation physiognomies to discuss on abiotic factors related to Restinga Forest stability and recovery potential. This work was carried out in several points of Restinga Forest in the litoral coast of the state of São Paulo, namely: State Park of the Serra do Mar, Picinguaba, in the city of Ubatuba (23°20' e 23°22' S / 44°48' e 44°52' W); State Park of Anchieta Island, in the city of Ubatuba (45°02' e 45°05' W / 23°31' e 23° 45' S); Restinga Forest in the residential joint ownership Riviera of São Lourenço, in the city of Bertioga (46°08' W e 23°51' S); Ecological Station Juréia-Itatins, Ecological Station of Chauas , in the city of Iguape (24°45' S e 47°33' W) and State Park of Cardoso Island, Pereirinha Restinga Forest, in the city of Cananéia (25°03'05" e 25°18'18" S / 47°53'48" e 48° 05'42" W), Brazil. Sampling was carried out as follows in every area above mentioned. One sample was made of 15 subsamples of each area collected in each depth (one in 0 - 5, 5 - 10, 10 - 15, 15 - 20, and another in 0 - 20, 20 - 40, 40 and 60 cm). Soil characteristics analyzed were pH, P, Na, K, Ca, Mg, S, H + Al, Al, B, Cu, Fe, Mn, Zn contents and base saturation, cation exchange capacity and aluminum saturation. All areas investigated showed very low contents of phosphorous, calcium and magnesium. The base saturation, less than 10, was low due to low amounts of Na, K, Ca and Mg, indicating low nutritional reserve into the soil. The nutritional reserve is present primarily in a depth of 15 cm, although mainly in the vegetable biomass. The level of calcium and magnesium were mainly low in the subsurface soil layer, associate with high concentration of aluminum, representing important limiting factor to the root system development in depth (≤ 15 cm). The aluminum saturation values to Restinga Forest reach 80% in depth and calcium varying from 1 to 2 mmolc dm-3. On this view, important questions on Restinga Forest development appears, mainly about species tolerance to aluminum in the soil and about the possibility of initial vegetative improvement as a function of soil fertility increasing, specially because low calcium and high Al decrease the root system development. Comparing the aluminum levels in the root and leaves to Psidium cattleyanum Sabine and Gomidesia Fenzliana O. Berg, the values were very superior in the leaves, indicating that aluminum is not maintained in the root system, being translocated to leaves.

NF546 [4,4'-(carbonylbis(imino-3,1-phenylene-carbonylimino-3,1-(4-methyl-phenylene)-carbonylimino))-bis(1,3-xylene-alpha,alpha'-diphosphonic acid) tetrasodium salt] is a non-nucleotide P2Y11 agonist and stimulates release of interleukin-8 from human monocyte-derived dendritic cells.

PubMed

Meis, Sabine; Hamacher, Alexandra; Hongwiset, Darunee; Marzian, Claudia; Wiese, Michael; Eckstein, Niels; Royer, Hans-Dieter; Communi, Didier; Boeynaems, Jean-Marie; Hausmann, Ralf; Schmalzing, Günther; Kassack, Matthias U

2010-01-01

The G protein-coupled P2Y(11) receptor is involved in immune system modulation. In-depth physiological evaluation is hampered, however, by a lack of selective and potent ligands. By screening a library of sulfonic and phosphonic acid derivatives at P2Y(11) receptors recombinantly expressed in human 1321N1 astrocytoma cells (calcium and cAMP assays), the selective non-nucleotide P2Y(11) agonist NF546 [4,4'-(carbonylbis(imino-3,1-phenylene-carbonylimino-3,1-(4-methyl-phenylene)carbonylimino))-bis(1,3-xylene-alpha,alpha'-diphosphonic acid) tetrasodium salt] was identified. NF546 had a pEC(50) of 6.27 and is relatively selective for P2Y(11) over P2Y(1), P2Y(2), P2Y(4), P2Y(6), P2Y(12), P2X(1), P2X(2), and P2X(2)-X(3). Adenosine-5'-O-(3-thio)triphosphate (ATPgammaS), a nonhydrolyzable analog of the physiological P2Y(11) agonist ATP, and NF546 use a common binding site as suggested by molecular modeling studies and their competitive behavior toward the nanomolar potency antagonist NF340 [4,4'-(carbonylbis(imino-3,1-(4-methyl-phenylene)carbonylimino))bis(naphthalene-2,6-disulfonic acid) tetrasodium salt] in Schild analysis. The pA(2) of NF340 was 8.02 against ATPgammaS and 8.04 against NF546 (calcium assays). NF546 was further tested for P2Y(11)-mediated effects in monocyte-derived dendritic cells. Similarly to ATPgammaS, NF546 led to thrombospondin-1 secretion and inhibition of lipopolysaccharide-stimulated interleukin-12 release, whereas NF340 inhibited these effects. Further, for the first time, it was shown that ATPgammaS or NF546 stimulation promotes interleukin 8 (IL-8) release from dendritic cells, which could be inhibited by NF340. In conclusion, we have described the first selective, non-nucleotide agonist NF546 for P2Y(11) receptors in both recombinant and physiological expression systems and could show a P2Y(11)-stimulated IL-8 release, further supporting the immunomodulatory role of P2Y(11) receptors.

Antioxidant and cytoprotective activities of Piper betle, Areca catechu, Uncaria gambir and betel quid with and without calcium hydroxide

PubMed Central

2013-01-01

Background Betel quid chewing is a popular habit in Southeast Asia. It is believed that chewing betel quid could reduce stress, strengthen teeth and maintain oral hygiene. The aim of this study was to investigate the antioxidant and cytoprotective activities of each of the ingredients of betel quid and compared with betel quid itself (with and without calcium hydroxide). The correlation of their cytoprotective and antioxidant activities with phenolic content was also determined. Methods Five samples (betel leaf, areca nut, gambir, betel quid and betel quid containing calcium hydroxide) were extracted in deionized distilled water for 12 hours at 37°C. Antioxidant activities were evaluated for radical scavenging activity using DPPH assay, ferric reducing activity using FRAP assay and lipid peroxidation inhibition activity using FTC assay. Total phenolic content (TPC) was determined using Folin-Ciocalteu procedure. Phenolic composition was analyzed using LC-MS/MS. Cytoprotective activity towards human gingival fibroblast cells was examined using MTT assay. Results Among the ingredients of betel quid, gambir demonstrated the highest antioxidant (DPPH - IC50 = 6.4 ± 0.8 μg/mL, FRAP - 5717.8 ± 537.6 μmol Fe(II)/mg), total phenolic content (TPC - 1142.5 ± 106.8 μg TAE/mg) and cytoprotective (100.1 ± 4.6%) activities. Betel quid when compared with betel quid containing calcium hydroxide has higher antioxidant (DPPH - IC50 =59.4 ± 4.4 μg/mL, FRAP - 1022.2 ± 235.7 μmol Fe(II)/mg), total phenolic content (TPC - 140.0 ± 22.3 μg TAE/mg), and cytoprotective (113.5 ± 15.9%) activities. However, all of the five samples showed good lipid peroxidation inhibition compared to vitamin E. LC-MS/MS analysis revealed the presence of quinic acid as the major compound of gambir and betel quid. A positive correlation was observed between TPC and radical scavenging (r = 0.972), reducing power (r = 0.981) and cytoprotective activity (r = 0.682). Conclusions The betel quid has higher TPC, and antioxidant and cytoprotective activities than betel quid with calcium hydroxide. The quinic acid in betel quid may play an important role in the oral health protection. PMID:24330738

21 CFR 181.29 - Stabilizers.

Code of Federal Regulations, 2012 CFR

2012-04-01

... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate. Calcium ricinoleate. Calcium stearate. Disodium hydrogen phosphate. Magnesium glycerophosphate. Magnesium...

21 CFR 181.29 - Stabilizers.

Code of Federal Regulations, 2010 CFR

2010-04-01

... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate. Calcium ricinoleate. Calcium stearate. Disodium hydrogen phosphate. Magnesium glycerophosphate. Magnesium...

21 CFR 181.29 - Stabilizers.

Code of Federal Regulations, 2011 CFR

2011-04-01

... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate. Calcium ricinoleate. Calcium stearate. Disodium hydrogen phosphate. Magnesium glycerophosphate. Magnesium...

21 CFR 181.29 - Stabilizers.

Code of Federal Regulations, 2013 CFR

2013-04-01

... glycerophosphate. Calcium phosphate. Calcium hydrogen phosphate. Calcium oleate. Calcium acetate. Calcium carbonate. Calcium ricinoleate. Calcium stearate. Disodium hydrogen phosphate. Magnesium glycerophosphate. Magnesium...

Mineralogy, early marine diagenesis, and the chemistry of shallow-water carbonate sediments

NASA Astrophysics Data System (ADS)

Higgins, J. A.; Blättler, C. L.; Lundstrom, E. A.; Santiago-Ramos, D. P.; Akhtar, A. A.; Crüger Ahm, A.-S.; Bialik, O.; Holmden, C.; Bradbury, H.; Murray, S. T.; Swart, P. K.

2018-01-01

Shallow-water carbonate sediments constitute the bulk of sedimentary carbonates in the geologic record and are widely used archives of Earth's chemical and climatic history. One of the main limitations in interpreting the geochemistry of ancient carbonate sediments is the potential for post-depositional diagenetic alteration. In this study, we use paired measurements of calcium (44Ca/40Ca or δ44Ca) and magnesium (26Mg/24Mg or δ26Mg) isotope ratios in sedimentary carbonates and associated pore-fluids as a tool to understand the mineralogical and diagenetic history of Neogene shallow-water carbonate sediments from the Bahamas and southwest Australia. We find that the Ca and Mg isotopic composition of bulk carbonate sediments at these sites exhibits systematic stratigraphic variability that is related to both mineralogy and early marine diagenesis. The observed variability in bulk sediment Ca isotopes is best explained by changes in the extent and style of early marine diagenesis from one where the composition of the diagenetic carbonate mineral is determined by the chemistry of the fluid (fluid-buffered) to one where the composition of the diagenetic carbonate mineral is determined by the chemistry of the precursor sediment (sediment-buffered). Our results indicate that this process, together with variations in carbonate mineralogy (aragonite, calcite, and dolomite), plays a fundamental and underappreciated role in determining the regional and global stratigraphic expressions of geochemical tracers (δ13C, δ18O, major, minor, and trace elements) in shallow-water carbonate sediments in the geologic record. Our results also provide evidence that a large shallow-water carbonate sink that is enriched in 44Ca can explain the mismatch between the δ44/40Ca value of rivers and deep-sea carbonate sediments and call into question the hypothesis that the δ44/40Ca value of seawater depends on the mineralogy of primary carbonate precipitations (e.g. 'aragonite seas' and 'calcite seas'). Finally, our results for sedimentary dolomites suggest that paired measurements of Ca and Mg isotopes may provide a unique geochemical fingerprint of mass transfer during dolomitization to better understand the paleo-environmental information preserved in these enigmatic but widespread carbonate minerals.

Paclitaxel Induces Apoptosis in Breast Cancer Cells through Different Calcium—Regulating Mechanisms Depending on External Calcium Conditions

PubMed Central

Pan, Zhi; Avila, Andrew; Gollahon, Lauren

2014-01-01

Previously, we reported that endoplasmic reticulum calcium stores were a direct target for paclitaxel initiation of apoptosis. Furthermore, the actions of paclitaxel attenuated Bcl-2 resistance to apoptosis through endoplasmic reticulum-mediated calcium release. To better understand the calcium-regulated mechanisms of paclitaxel-induced apoptosis in breast cancer cells, we investigated the role of extracellular calcium, specifically; whether influx of extracellular calcium contributed to and/or was necessary for paclitaxel-induced apoptosis. Our results demonstrated that paclitaxel induced extracellular calcium influx. This mobilization of extracellular calcium contributed to subsequent cytosolic calcium elevation differently, depending on dosage. Under normal extracellular calcium conditions, high dose paclitaxel induced apoptosis-promoting calcium influx, which did not occur in calcium-free conditions. In the absence of extracellular calcium an “Enhanced Calcium Efflux” mechanism in which high dose paclitaxel stimulated calcium efflux immediately, leading to dramatic cytosolic calcium decrease, was observed. In the absence of extracellular calcium, high dose paclitaxel’s stimulatory effects on capacitative calcium entry and apoptosis could not be completely restored. Thus, normal extracellular calcium concentrations are critical for high dose paclitaxel-induced apoptosis. In contrast, low dose paclitaxel mirrored controls, indicating that it occurs independent of extracellular calcium. Thus, extracellular calcium conditions only affect efficacy of high dose paclitaxel-induced apoptosis. PMID:24549172

Carboxymethyl Hyaluronan-Stabilized Nanoparticles for Anticancer Drug Delivery.

PubMed

Woodman, Jessica L; Suh, Min Sung; Zhang, Jianxing; Kondaveeti, Yuvabharath; Burgess, Diane J; White, Bruce A; Prestwich, Glenn D; Kuhn, Liisa T

2015-01-01

Carboxymethyl hyaluronic acid (CMHA) is a semisynthetic derivative of HA that is recognized by HA binding proteins but contains an additional carboxylic acid on some of the 6-hydroxyl groups of the N-acetyl glucosamine sugar units. These studies tested the ability of CMHA to stabilize the formation of calcium phosphate nanoparticles and evaluated their potential to target therapy resistant, CD44(+)/CD24(-/low) human breast cancer cells (BT-474EMT). CMHA stabilized particles (nCaP(CMHA)) were loaded with the chemotherapy drug cis-diamminedichloroplatinum(II) (CDDP) to form nCaP(CMHA)CDDP. nCaP(CMHA)CDDP was determined to be poorly crystalline hydroxyapatite, 200 nm in diameter with a -43 mV zeta potential. nCaP(CMHA)CDDP exhibited a two-day burst release of CDDP that tapered resulting in 86% release by 7 days. Surface plasmon resonance showed that nCaP(CMHA)CDDP binds to CD44, but less effectively than CMHA or hyaluronan. nCaP(CMHA-AF488) was taken up by CD44(+)/CD24(-) BT-474EMT breast cancer cells within 18 hours. nCaP(CMHA)CDDP was as cytotoxic as free CDDP against the BT-474EMT cells. Subcutaneous BT-474EMT tumors were more reproducibly inhibited by a near tumor dose of 2.8 mg/kg CDDP than a 7 mg/kg dose nCaP(CMHA)CDDP. This was likely due to a lack of distribution of nCaP(CMHA)CDDP throughout the dense tumor tissue that limited drug diffusion.

Calcium and Oxygen Isotopic Composition of Calcium Carbonates

NASA Astrophysics Data System (ADS)

Niedermayr, Andrea; Eisenhauer, Anton; Böhm, Florian; Kisakürek, Basak; Balzer, Isabelle; Immenhauser, Adrian; Jürgen Köhler, Stephan; Dietzel, Martin

2016-04-01

Different isotopic systems are influenced in multiple ways corresponding to the crystal structure, dehydration, deprotonation, adsorption, desorption, isotope exchange and diffusion processes. In this study we investigated the structural and kinetic effects on fractionation of stable Ca- and O-isotopes during CaCO3 precipitation. Calcite, aragonite and vaterite were precipitated using the CO2 diffusion technique[1]at a constant pH of 8.3, but various temperatures (6, 10, 25 and 40° C) and precipitation rates R (101.5 to 105 μmol h-1 m-2). The calcium isotopic fractionation between solution and vaterite is lower (Δ44/40Ca= -0.10 to -0.55 ‰) compared to calcite (-0.69 to -2.04 ‰) and aragonite (-0.91 to -1.55 ‰). In contrast the fractionation of oxygen isotopes is highest for vaterite (32.1 ‰), followed by aragonite (29.2 ‰) and calcite (27.6 ‰) at 25° C and equilibrium. The enrichment of 18O vs. 16O in all polymorphs decreases with increasing precipitation rate by around -0.7 ‰ per log(R). The calcium isotopic fractionation between calcite/ vaterite and aqueous Ca2+ increases with increasing precipitation rate by ˜0.45 ‰ per log(R) and ˜0.1 ‰ per log(R) at 25° C and 40° C, respectively. In contrast the fractionation of Ca-isotopes between aragonite and aqueous Ca2+ decreases with increasing precipitation rates. The large enrichment of 18O vs. 16O isotopes in carbonates is related to the strong bond of oxygen to the small and highly charged C4+-ion. In contrast equilibrium isotopic fractionation between solution and calcite or vaterite is nearly zero as the Ca-O bond length is similar for calcite, vaterite and the hydrated Ca. Aragonite incorporates preferentially the lighter 40Ca isotope as it has very large Ca-O bonds in comparison to the hydrated Ca. At the crystal surface the lighter 40Ca isotopes are preferentially incorporated as dehydration and diffusion of lighter isotopes are faster. Consequently, the surface becomes enriched in 40Ca. On the other hand, 40Ca may desorb more easily, especially if the bond strength is lower as in the case of aragonite. For kinetic oxygen isotopic fractionation, the faster deprotonation of HC16O3- and the faster incorporation of C16O32- at the surfaces causes a smaller enrichment of 18O in all three polymorphs, which will be preserved at higher precipitation rates. In consequence to the different behavior of calcium and oxygen isotopes, they can be useful for multiproxy applications. Thereby calcium isotopes can be used to identify kinetic effects, especially if both aragonite and calcite, can be analyzed in one sample. Oxygen isotopes are more strongly related to temperature. [1]A. Niedermayr, S.J. Köhler and M. Dietzel (2013), Chemical Geology, 340, 105-120.

Effect of different mixing methods on the bacterial microleakage of calcium-enriched mixture cement.

PubMed

Shahi, Shahriar; Jeddi Khajeh, Soniya; Rahimi, Saeed; Yavari, Hamid R; Jafari, Farnaz; Samiei, Mohammad; Ghasemi, Negin; Milani, Amin S

2016-10-01

Calcium-enriched mixture (CEM) cement is used in the field of endodontics. It is similar to mineral trioxide aggregate in its main ingredients. The present study investigated the effect of different mixing methods on the bacterial microleakage of CEM cement. A total of 55 human single-rooted human permanent teeth were decoronated so that 14-mm-long samples were obtained and obturated with AH26 sealer and gutta-percha using lateral condensation technique. Three millimeters of the root end were cut off and randomly divided into 3 groups of 15 each (3 mixing methods of amalgamator, ultrasonic and conventional) and 2 negative and positive control groups (each containing 5 samples). BHI (brain-heart infusion agar) suspension containing Enterococcus faecalis was used for bacterial leakage assessment. Statistical analysis was carried out using descriptive statistics, Kaplan-Meier survival analysis with censored data and log rank test. Statistical significance was set at P<0.05. The survival means for conventional, amalgamator and ultrasonic methods were 62.13±12.44, 68.87±12.79 and 77.53±12.52 days, respectively. The log rank test showed no significant differences between the groups. Based on the results of the present study it can be concluded that different mixing methods had no significant effect on the bacterial microleakage of CEM cement.

Distinct action of aranidipine and its active metabolite on renal arterioles, with special reference to renal protection.

PubMed

Nakamura, A; Hayashi, K; Fujiwara, K; Ozawa, Y; Honda, M; Saruta, T

2000-06-01

Aranidipine, a newly developed calcium antagonist, possesses unique pharmacologic characteristics in that its metabolite (M-1) still has antihypertensive action. We examined the effects of both agents on renal microcirculation using the isolated perfused hydronephrotic rat kidney. During norepinephrine-induced constriction, the addition of aranidipine dilated both afferent and efferent arterioles in a dose-dependent manner; at 10(-6) M, 83 +/- 6% and 90 +/- 6% reversal, respectively. In contrast, its active metabolite exerted dilator action predominantly on the afferent arteriole (79 +/- 4% vs. 44 +/- 17% at 10(-6) M for afferent and efferent arterioles, respectively). We further examined the long-term (8 weeks) effect of these agents on the development of renal injury in salt-loaded subtotally nephrectomized spontaneously hypertensive rats. Both aranidipine and M-1 reduced blood pressure by a similar magnitude. The decreases in proteinuria were observed in the aranidipine-treated group at weeks 6, 8, and 10, whereas in the M-1 group, significant reduction was attained only at week 6. Histopathologic examination revealed that both treatments improved glomerular and arteriolar sclerosis. Glomerular sclerosis, however, was less pronounced in the aranidipine-treated group than in the M-1 group. In conclusion, aranidipine has dilator action on both arterioles, whereas M-1 caused predominant dilation of afferent arterioles. Such metabolic changes may constitute a determinant of efferent arteriolar action of the calcium antagonist.

Characterization of nanoscopic calcium fluoride films

NASA Astrophysics Data System (ADS)

Rehmer, A.; Kemnitz, E.

2016-09-01

Nano metal fluorides are appropriate materials for different applications e.g. heterogeneous catalysis, ceramic materials for laser applications and antireflective layers on glass, respectively. An easy way to synthesize such nano metal fluorides is the fluorolytic sol-gel synthesis which was developed some few years ago for HS-AlF3 [1] and MgF2.[2] CaF2 exhibits similar optical properties as MgF2, and thus, is a promising candidate for antireflective (AR) coatings. That means, CaF2 exhibits a lower refractive index (n500 = 1.44) as compared to common soda lime glass (n500 = 1.53). Hence, we present an easy synthesis approach toward nanoscaled CaF2 sols to fabricate finally AR-CaF2 films by dip coating. Irrespective of the choice of the calcium precursor, the CaF2 films are porous in comparison to thin dense CaF2 films which are generated by physical vapor deposition. The characterization of CaF2 films was performed by different analytical methods like HR-SEM, XPS, EDX, EP (ellipsometric porosimetry), DLS (dynamic light scattering) and CA (contact angle measurement). Beside the good optical and mechanical properties, we have investigated the surface properties of CaF2 films on glass and silicon wafer e.g. surface morphology with elemental composition, open porosity, zeta potentials at the surfaces as well as the free energy of interaction between water and the CaF2 film.

Determining appropriate nutritional interventions for South African children living in informal urban settlements.

PubMed

Coutsoudis, A; Jinabhai, C C; Coovadia, H M; Mametja, L D

1994-09-01

Rapid urbanisation in South Africa has led to the creation of informal shack settlements where the health status of children is in jeopardy; it needs to be monitored so that appropriate intervention strategies can be formulated. Accordingly, the nutritional status of 190 children (3-6 years of age) living in Besters, a typical urban shack settlement north of Durban, was assessed anthropometrically. In addition the following biochemical values were determined: vitamins A and E, calcium, magnesium, phosphorus, albumin, haemoglobin, serum iron and ferritin and percentage of transferrin saturation. Malnutrition was evident in 13% of the children who were underweight (below the National Center for Health Statistics (NCHS) third weight-for-age percentile) and 27% who were stunted (below the NCHS third height-for-age percentile). Concentrations of albumin, calcium, magnesium, phosphorus and vitamin E were close to normal, with no more than 10% of the sample having values outside the normal range. However, 44% of the children had low serum retinol levels (< 20 micrograms/dl) and 21% of the children had anaemia (haemoglobin < 11 micrograms/dl). Significant positive correlations were found between serum retinol and all biochemical indicators of iron status except serum ferritin. This study highlights the fact that nutrient deficiencies are interrelated, particularly protein energy malnutrition and poor vitamin A and iron status. A broad multifaceted comprehensive health intervention programme is therefore required.

Treatment of hyperinsulinemic hypoglycemia because of diffuse nesidioblastosis with nifedipine after surgical therapies in a newborn.

PubMed

Koklu, Esad; Ozkan, Keramettin Uğur; Sayar, Hamide; Koklu, Selmin; Keskin, Mehmet

2013-01-01

Recent studies have demonstrated a role for calcium channel blocking agents in the treatment of persistent hyperinsulinemic hypoglycemia of newborns. We report a newborn infant with persistent hyperinsulinemic hypoglycemia whom we successfully treated with oral nifedipine alone after surgical therapies. A 4-day-old male infant was referred with intractable hypoglycemia and seziures. Normoglycaemia could be maintained only by the intravenous infusion of glucose at a rate of 20 mg/kg per minute. Persistent hyperinsulinemic hypoglycemia of newborn was diagnosed from an inappropriately raised plasma insulin concentration (44 mU/L) at the time of hypoglycemia. Medical treatments led to only a mild reduction in the intravenous glucose requirement; an 85-90% pancreatectomy was performed and histological "diffuse nesidioblastosis" was confirmed. However, despite all the medical treatments after the first pancreatectomy, the hyperinsulinemic hypoglycemia persisted and a second 95% pancreatectomy was performed. After the second pancreatectomy, persistent hyperinsulinemic hypoglycemia was treated with somatostatin and diazoxide, but led to no reduction in the intravenous glucose requirement. We report the case of an infant who had persistent hypoglycemia after two subtotal pancreatic resections but subsequently became normoglycemic on treatment with nifedipine (2 mg/kg per day). The patient was discharged home on oral nifedipine. Calcium channel blocking agents cuold be used with efficacy and safety in recurrent persistent hyperinsulinemic hypoglycemia.

Zinc-Containing Restorations Create Amorphous Biogenic Apatite at the Carious Dentin Interface: A X-Ray Diffraction (XRD) Crystal Lattice Analysis.

PubMed

Toledano, Manuel; Aguilera, Fátima S; López-López, Modesto T; Osorio, Estrella; Toledano-Osorio, Manuel; Osorio, Raquel

2016-10-01

The aim of this research was to assess the ability of amalgam restorations to induce amorphous mineral precipitation at the caries-affected dentin substrate. Sound and caries-affected dentin surfaces were subjected to both Zn-free and Zn-containing dental amalgam restorations. Specimens were submitted to thermocycling (100,000 cycles/5°C-55°C, 3 months). Dentin surfaces were studied by atomic force microscopy (nanoroughness), X-ray diffraction, field emission scanning electron microscopy, and energy-dispersive analysis, for physical and morphological surface characterization. Zn-containing amalgam placement reduced crystallinity, crystallite size, and grain size of calcium phosphate crystallites at the dentin surface. Both microstrain and nanoroughness were augmented in caries-affected dentin restored with Zn-containing amalgams. Caries-affected dentin showed the shortest mineral crystallites (11.04 nm), when Zn-containing amalgams were used for restorations, probably leading to a decrease of mechanical properties which might favor crack propagation and deformation. Sound dentin restored with Zn-free amalgams exhibited a substantial increase in length of grain particles (12.44 nm) embedded into dentin crystallites. Zn-containing amalgam placement creates dentin mineralization and the resultant mineral was amorphous in nature. Amorphous calcium phosphate provides a local ion-rich environment, which is considered favorable for in situ generation of prenucleation clusters, promotong further dentin remineralization.

Dietary supplementation of grape seed and skin flour mitigates brain oxidative damage induced by a high-fat diet in rat: Gender dependency.

PubMed

Charradi, Kamel; Mahmoudi, Mohamed; Bedhiafi, Takwa; Kadri, Safwen; Elkahoui, Salem; Limam, Ferid; Aouani, Ezzedine

2017-03-01

It is unknown whether gender has an impact on brain injury in obesity, and, if so, whether treatment with grape seed and skin flour could exert a protective effect. Both male and female rats were fed a standard diet (SD) or a high fat diet (HFD) during eight weeks and treated with high dosage grape seed and skin flour (GSSF). Fat-induced oxidative stress was evaluated into the brain with a special emphasis on transition metals determination. HFD induced male-cholesterol overload (+78.12%) and an oxidative stress status characterized by increased lipoperoxidation (+68.97%), carbonylation (+40.28%), decreased antioxidant enzyme activities as glutathione peroxidase (-61.07%) and manganese-superoxide dismutase (-35.47%) but not catalase. Additionally HFD depleted the brain from manganese (-71.31%) and dropped glutamine synthetase activity (-36.16%), without affecting copper nor iron nor their associated enzymes. HFD also altered intracellular mediators as superoxide anion (+36.12%), calcium (+44.41%) and also calpain (+76.54%) a calcium dependent protease. Importantly all these alterations were detected exclusively in male brain and were efficiently corrected upon GSSF treatment. In conclusion, GSSF has the potential to alleviate the deleterious lipotoxic effect of HFD treatment that occurred in male brain and perhaps in post-menauposal female brain. Copyright © 2017 Elsevier Masson SAS. All rights reserved.

Long-timescale molecular dynamics simulations elucidate the dynamics and kinetics of exposure of the hydrophobic patch in troponin C.

PubMed

Lindert, Steffen; Kekenes-Huskey, Peter M; McCammon, J Andrew

2012-10-17

Troponin (Tn) is an important regulatory protein in the thin-filament complex of cardiomyocytes. Calcium binding to the troponin C (TnC) subunit causes a change in its dynamics that leads to the transient opening of a hydrophobic patch on TnC's surface, to which a helix of another subunit, troponin I (TnI), binds. This process initiates contraction, making it an important target for studies investigating the detailed molecular processes that underlie contraction. Here we use microsecond-timescale Anton molecular dynamics simulations to investigate the dynamics and kinetics of the opening transition of the TnC hydrophobic patch. Free-energy differences for opening are calculated for wild-type Ca(2+)-bound TnC (∼8 kcal/mol), V44Q Ca(2+)-bound TnC (3.2 kcal/mol), E40A Ca(2+)-bound TnC (∼12 kcal/mol), and wild-type apo TnC (∼20 kcal/mol). These results suggest that the mutations have a profound impact on the frequency with which the hydrophobic patch presents to TnI. In addition, these simulations corroborate that cardiac wild-type TnC does not open on timescales relevant to contraction without calcium being bound. Copyright © 2012 Biophysical Society. Published by Elsevier Inc. All rights reserved.

Load dependence of left ventricular contraction and relaxation. Effects of caffeine.

PubMed

Leite-Moreira, A F; Correia-Pinto, J; Gillebert, T C

1999-08-01

Load dependence of left ventricular (LV) contraction and relaxation was investigated at baseline and after alteration of intracellular calcium handling by caffeine. Afterload was increased by aortic clamp occlusions (n = 281) in anesthetized open-chest dogs (n = 7). Control and first heartbeat after the intervention were considered for analysis. Caffeine (50 mg/kg, iv) had no inotropic effect. The systolic LV pressure (LVP), developed in response to aortic occlusion, decreased as ejection proceeded and this pressure generating capacity was not affected by caffeine. Late-systolic aortic occlusions induced premature onset and accelerated rate of initial LVP fall at baseline and similarly after caffeine. Graded diastolic aortic occlusions induced systolic LVP elevations of various magnitudes. Smaller LVP elevations prolonged ejection and accelerated LVP fall, while larger elevations had opposite effects. The transition from acceleration to deceleration was observed at 83.1 +/- 1.1% of peak isovolumetric LVP at baseline and at lower loads, at 77.6 +/- 1.2%, after caffeine (p < 0.01). Isovolumetric heartbeats prolonged the time constant tau by 238 +/- 70% at baseline and only by 155 +/- 44% after caffeine (p < 0.01). The relaxation-systolic pressure relation, which describes afterload dependence of relaxation, was also modified by caffeine. Caffeine affected LV relaxation without altering contractility. As a consequence contraction-relaxation coupling was modified by caffeine. These results might help to understand load dependence of relaxation in conditions where intracellular calcium handling is altered.

An Independent Constraint on Marine Sulfate Levels at the Ediacaran-Cambrian Transition

NASA Astrophysics Data System (ADS)

Blättler, C. L.; Bergmann, K.; Higgins, J. A.

2016-12-01

Sediments from the Ediacaran-Cambrian transition in Oman record major excursions in the isotopic systems of carbon (δ13C) and sulfur (δ34S). The significance of these geochemical signals has been the subject of much debate, focusing on their association with biotic innovations and extinctions, oxygenation of the atmosphere and oceans, and changes in seawater chemistry. The concentration of marine sulfate during this time interval remains particularly uncertain, despite being a critical variable for several hypotheses related to these excursions. We present an independent constraint on relative sulfate concentrations based on calcium-isotope data from the Ara Group evaporites (547-540 Ma) of the South Oman Salt Basin. Anhydrite samples from five boreholes span the A1 through A5 carbonate-evaporite sequences, lying on both sides of the Precambrian-Cambrian boundary. The approach developed by Blättler and Higgins (2014) is used to quantify the degree of isotopic distillation of calcium by sulfate mineral precipitation. The absence of significant distillation (expressed by δ44/40Ca variability in the anhydrite) suggests that Ca/SO4 ratios in the latest Ediacaran and earliest Cambrian were greater than during the Neogene or Permian. These results, together with previously published analyses of halite fluid inclusions and models of sulfur cycling, give a clearer estimate of how marine sulfate levels may have evolved during this dynamic period in Earth history.

Evaluation of Antimicrobial Activities of Sequential Spray Applications of Decontamination Treatments on Chicken Carcasses

PubMed Central

Benli, Hakan; Sanchez-Plata, Marcos X.; Ilhak, Osman Irfan; Núñez De González, Maryuri T.; Keeton, Jimmy T.

2015-01-01

The objective of this study was to evaluate the effects of sequential applications of ɛ-polylysine (EPL) or lauramide arginine ethyl ester (LAE) sprays followed by an acidic calcium sulfate (ACS) spray on inoculated chicken carcasses to reduce Salmonella (Salmonella enterica serovars including Salmonella typhimurium and Salmonella enteritidis) contamination during 6 days of storage (4.4°C). Secondly, reductions of the resident microflora were studied on uninoculated chicken carcasses following the sequential application of the treatments, chilling and 10 days of storage at 4.4°C. The treatment of Salmonella inoculated carcasses with 300 mg/L EPL followed by 30% ACS (EPL300-ACS30) sprays reduced Salmonella counts initially by 1.5 log cfu/mL and then by 1.2 log cfu/mL (p<0.05) following 6 days of storage at 4.4°C. Likewise, 200 mg/L LAE followed by 30% ACS (LAE200-ACS30) treatment reduced initial Salmonella counts on poultry carcasses by 1.8, 1.4 and 1.8 log cfu/mL (p<0.05), respectively, after 0, 3, and 6 days storage. Immediately after the treatments, EPL300-ACS30 and LAE200-ACS30 both reduced Escherichia coli counts significantly by 2.6 and 2.9 log cfu/mL, respectively. EPL300-ACS30 and LAE200-ASC30 were effective in lowering psychrotroph counts by 1 log cfu/mL on day 10 when compared to the control and distilled water treatments. This study demonstrated that EPL300-ACS30 and LAE200-ACS30 were effective in reducing Salmonella on inoculated chicken carcasses both after treatment and during the storage at 4.4°C for up to 6 days. In addition, reductions in psychrotroph counts indicated that these treatments might have the potential to increase the shelf-life of poultry carcasses. PMID:25656180

Oral calcium carbonate affects calcium but not phosphorus balance in stage 3–4 chronic kidney disease

PubMed Central

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

2014-01-01

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

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

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate, calcium chloride double salt... 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...

Consumption of fortified infant foods reduces dietary diversity but has a positive effect on subsequent growth in infants from Sumedang district, Indonesia

PubMed Central

Mallard, Simonette R.; Haszard, Jillian J.; Purnamasari, Dwi Monik; Nurulazmi, Ikrimah; Herliani, Pratami D.; Nugraha, Gaga I.; Gibson, Rosalind S.; Houghton, Lisa

2017-01-01

Stunting and underweight among under-five children in Indonesia are common, raising public health concerns. Whether inappropriate complementary feeding (CF) practices compromise optimal growth during late infancy in Indonesia is uncertain. Therefore we characterized and evaluated CF practices in Indonesian infants and investigated their relationship with subsequent growth. We enrolled breastfed infants at 6 months of age (n = 230); and followed them at 9 (n = 202) and 12 months of age (n = 190). We collected socio-demographic and anthropometric data and two-day in-home weighed food records. Relations between WHO CF indicators, sentinel foods, and energy and micronutrient intakes at 9 months and growth at 12 months were explored using multiple linear regression. Stunting and underweight increased from 15.8% and 4.4% at 6 months to 22.6% and 10.5% at 12 months, respectively. Median intakes of calcium, iron, zinc, and riboflavin were below WHO recommendations. Infants consuming fortified infant foods (FIFs) at 9 months had diets with a lower dietary diversity (DD) score (2.3 vs.3.0), energy density, median energy (250 vs. 310 kcal/d) and protein (6.5 vs. 9.1 g/d) intake than non-consumers (p<0.01), despite higher intakes of calcium, iron, and vitamins A and C (p<0.001). Positive relations existed for 9-month consumption of iron-rich/iron fortified infant foods with length-for-age Z-score (LAZ) at 12 months (β = 0.22; 95% CI: 0.01, 0.44; P = 0.04), and for fortified infant foods alone with both LAZ (β = 0.29; 95% CI: 0.09, 0.48; P = 0.04) and weight-for-age Z-score (β = 0.14; 95% CI: 0.02, 0.26; P = 0.02) at 12 months. The positive association of FIFs with subsequent growth may be attributed to their content of both powdered cow’s milk and multi-micronutrient fortificants. Nonetheless, mothers should not be encouraged to over-rely on FIFs as they reduce DD. PMID:28426828

Vitamin D, parathyroid hormone, and acroosteolysis in systemic sclerosis.

PubMed

Braun-Moscovici, Yolanda; Furst, Daniel E; Markovits, Doron; Rozin, Alexander; Clements, Philip J; Nahir, Abraham Menahem; Balbir-Gurman, Alexandra

2008-11-01

.Sclerodactyly with acroosteolysis (AO) and calcinosis are prominent features of systemic sclerosis (SSc), but the pathogenesis of these findings is poorly understood. Vitamin D and parathyroid hormone (PTH) have a crucial role in bone metabolism and resorption and may affect AO and calcinosis. We assessed vitamin D and PTH in patients with SSc. Medical records of 134 consecutive patients with SSc (American College of Rheumatology criteria) followed at the rheumatology department during the years 2003-2006 were reviewed for clinical assessment, laboratory evaluation [including 25(OH) vitamin D, calcium, phosphorus, alkaline phosphatase, PTH, creatinine, and albumin]; imaging data confirming AO and/or calcinosis. Patients followed routinely at least once a year were included (81 patients). Of these, 60 patients' medical records were found to have complete, relevant clinical, laboratory, and radiographic imaging. Thirteen patients had diffuse disease and 47 limited disease - 51 women and 9 men, 44 Jews and 16 Arabs; mean age 55 +/- 14 years; disease duration 8 +/- 6 years. AO with or without calcinosis was observed in 42 patients (70%). Vitamin D deficiency was found in 46% of patients (16 out of 44 Jewish patients, 10 out of 16 Arab patients). PTH was elevated in 21.7% of patients. Significant correlations were observed between acroosteolysis and PTH (p = 0.015), calcinosis (p = 0.009), and disease duration (p = 0.008), and between PTH and vitamin D levels (p = 0.01). All patients had normal serum concentrations of calcium, phosphorus, magnesium, and albumin, and liver and kidney functions. In this group of Mediterranean patients with SSc, the incidence of vitamin D deficiency and secondary hyperparathyroidism was surprisingly high. This finding correlated with the occurrence of AO and calcinosis. Low levels of vitamin D may reflect silent malabsorption and might be a risk factor for secondary hyperparathyroidism and bone resorption. Traditional dress habits and low exposure to sun may contribute to vitamin D deficiency in an Arab population but do not explain all the findings. The pathogenesis of these findings needs to be corroborated in other SSc populations.

Nutritional intake of elite football referees.

PubMed

Teixeira, Vitor Hugo; Gonçalves, Liliana; Meneses, Tiago; Moreira, Pedro

2014-01-01

There is a paucity of dietary data in football referees. In this study, 23 elite main and assistant referees (34.4 ± 5.6 years) completed a 7-day dietary record during the competitive season. No nutritional intake differences were observed between main and assistant referees. Referees' mean daily energy intake (DEI) was 2819 ± 279 kcal. The intake of proteins (1.7 ± 0.2 g · kg(-1)), carbohydrates (4.1 ± 0.8 g · kg(-1)) and fats (1.4 ± 0.2 g · kg(-1)) represented, respectively, 18.4 ± 1.5%, 44.4 ± 4.4% and 34.6 ± 4.1% of the DEI. Carbohydrate intakes before, during and after exercise were 66 ± 42, 7 ± 15 and 120 ± 62 g. Daily carbohydrate, fibre, polyunsaturated fat and water intakes were below recommendations, while fat, saturated fat, cholesterol and sodium intakes were above recommended values. The prevalence of inadequate intake was high for vitamin E (96%), folate (74%), vitamin A (61%), vitamin C (39%), magnesium (26%) and calcium (22%). Carbohydrate intake before, during and after exercise were far from achieving the minimum recommended values. Most referees demonstrated a negligent behaviour of hydration during exercise. Referees would benefit from dietary education in order to optimise performance and health.

Expression and agonist responsiveness of CXCR3 variants in human T lymphocytes.

PubMed

Korniejewska, Anna; McKnight, Andrew J; Johnson, Zoë; Watson, Malcolm L; Ward, Stephen G

2011-04-01

The chemokine receptor CXCR3 and its ligands CXCL9, CXCL10 and CXCL11 are involved in variety of inflammatory disorders including multiple sclerosis, rheumatoid arthritis, psoriasis and sarcoidosis. Two alternatively spliced variants of the human CXCR3-A receptor have been described, termed CXCR3-B and CXCR3-alt. Human CXCR3-B binds CXCL9, CXCL10, CXCL11 as well as an additional ligand CXCL4. In contrast, CXCR3-alt only binds CXCL11. We report that CXCL4 induces intracellular calcium mobilization as well as Akt and p44/p42 extracellular signal-regulated kinase phosphorylation, in activated human T lymphocytes. These responses have similar concentration dependence and time-courses to those induced by established CXCR3 agonists. Moreover, phosphorylation of Akt and p44/p42 is inhibited by pertussis toxin, suggesting coupling to Gα(i) protein. Surprisingly, and in contrast with the other CXCR3 agonists, stimulation of T lymphocytes with CXCL4 failed to elicit migratory responses and did not lead to loss of surface CXCR3 expression. Taken together, our findings show that, although CXCL4 is coupled to downstream biochemical machinery, its role in T cells is probably distinct from that of CXCR3-A agonists. © 2011 The Authors. Immunology © 2011 Blackwell Publishing Ltd.

Expression and agonist responsiveness of CXCR3 variants in human T lymphocytes

PubMed Central

Korniejewska, Anna; McKnight, Andrew J; Johnson, Zoë; Watson, Malcolm L; Ward, Stephen G

2011-01-01

The chemokine receptor CXCR3 and its ligands CXCL9, CXCL10 and CXCL11 are involved in variety of inflammatory disorders including multiple sclerosis, rheumatoid arthritis, psoriasis and sarcoidosis. Two alternatively spliced variants of the human CXCR3-A receptor have been described, termed CXCR3-B and CXCR3-alt. Human CXCR3-B binds CXCL9, CXCL10, CXCL11 as well as an additional ligand CXCL4. In contrast, CXCR3-alt only binds CXCL11. We report that CXCL4 induces intracellular calcium mobilization as well as Akt and p44/p42 extracellular signal-regulated kinase phosphorylation, in activated human T lymphocytes. These responses have similar concentration dependence and time–courses to those induced by established CXCR3 agonists. Moreover, phosphorylation of Akt and p44/p42 is inhibited by pertussis toxin, suggesting coupling to Gαi protein. Surprisingly, and in contrast with the other CXCR3 agonists, stimulation of T lymphocytes with CXCL4 failed to elicit migratory responses and did not lead to loss of surface CXCR3 expression. Taken together, our findings show that, although CXCL4 is coupled to downstream biochemical machinery, its role in T cells is probably distinct from that of CXCR3-A agonists. PMID:21255008

Interactions between the Tetrasodium Salts of EDTA and 1-Hydroxyethane 1,1-Diphosphonic Acid with Sodium Hypochlorite Irrigants.

PubMed

Biel, Philippe; Mohn, Dirk; Attin, Thomas; Zehnder, Matthias

2017-04-01

A clinically useful all-in-one endodontic irrigant with combined proteolytic and decalcifying properties is still elusive. In this study, the chemical effects of dissolving the tetrasodium salts of 1-hydroxyethane 1,1-diphosphonic acid (Na 4 HEDP) or Na 4 EDTA directly in sodium hypochlorite (NaOCl) irrigants in polypropylene syringes were assessed during the course of 1 hour. The solubility of the salts in water was determined. Their compatibility with 1% and 5% NaOCl was measured by iodometric titration and in a calcium complexation experiment by using a Ca 2+ -selective electrode. The salts dissolved within 1 minute. The dissolution maximum of Na 4 HEDP in water (wt/total wt) was 44.6% ± 1.6%. The corresponding dissolution maximum of Na 4 EDTA was 38.2% ± 0.8%. Na 4 HEDP at 18% in 5% NaOCl caused a mere loss of 16% of the initially available chlorine during 1 hour. In contrast, a corresponding mixture between NaOCl and the Na 4 EDTA salt caused 95% reduction in available chlorine after 1 minute. Mixtures of 3% Na 4 EDTA with 1% NaOCl were more stable, but only for 30 minutes. Na 4 HEDP lost 24% of its calcium complexation capacity after 60 minutes. The corresponding loss for Na 4 EDTA was 34%. The compatibility and solubility of particulate Na 4 HEDP with/in NaOCl solutions are such that these components can be mixed and used for up to 1 hour. In contrast, short-term compatibility of the Na 4 EDTA salt with NaOCl solutions was considerably lower, decreasing at higher concentrations of either compound. Especially for Na 4 HEDP but also for Na 4 EDTA, the NaOCl had little effect on calcium complexation. Copyright © 2017 American Association of Endodontists. Published by Elsevier Inc. All rights reserved.

Calcifying tendinitis of the shoulder: midterm results after arthroscopic treatment.

PubMed

Balke, Maurice; Bielefeld, Rebecca; Schmidt, Carolin; Dedy, Nicolas; Liem, Dennis

2012-03-01

Calcifying tendinitis is a common and painful disorder of the shoulder characterized by the presence of calcific deposits in the tendons of the rotator cuff. When nonoperative treatment over a prolonged period of time fails, surgical treatment should be considered. Midterm success rates are inconsistent, and the role of subacromial decompression is still unclear. Our hypotheses were that the rate of supraspinatus tears after arthroscopic treatment of calcifying tendinitis is comparable with that in the contralateral uninvolved shoulder and that subacromial decompression does not have beneficial effects compared with calcium removal alone. Case series; Level of evidence, 4. In 70 shoulders of 62 patients with a mean age of 54 years, arthroscopic removal of calcium deposits of the supraspinatus tendon was performed. In 44 shoulders, additional subacromial decompression was performed. After a mean follow-up of 6 years (range, 2-13 years), patients were clinically investigated, and function was statistically evaluated using Constant and American Shoulder and Elbow Surgeons (ASES) scores. Affected and contralateral shoulders were examined by ultrasound in 48 shoulders, and rotator cuff tears were documented. The mean Constant scores of the operated shoulders were significantly lower than those of the healthy shoulders (P < .001). The ASES scores significantly (P < .001) increased after surgery but were still lower than the ASES scores of the healthy shoulders (P < .001). Concerning the additional subacromial decompression, there were no significant differences in the overall ASES and Constant scores; the subitem "pain" was significantly better in the subacromial decompression group (P = .048). Ultrasound examination at last follow-up (48 shoulders) showed a partial supraspinatus tendon tear in 11 operated and 3 contralateral shoulders. Although the good clinical results after arthroscopic treatment of calcifying tendinitis of the shoulder persist midterm, the affected shoulders present significantly lower clinical scores than healthy shoulders. The rate of partial supraspinatus tendon tears seems to be higher after calcium removal. Additional subacromial decompression seems to reduce postoperative pain.

Effects of heat shock on neuroblastoma (N1E 115) cell proliferation and differentiation.

PubMed

Stoklosinski, A; Kruse, H; Richter-Landsberg, C; Rensing, L

1992-05-01

Heat shock (44 degrees C) applied for only 15 min induced the development of neurites in neuroblastoma cells 3-6 days later. During the first day after heat shock a transient increase in the rate of cytokinesis together with a synchronizing effect was observed, which led to waves of cytokinesis 14.5 h apart. Individual cell cycles were determined and showed a lengthening in the minimal cell cycle duration and a decrease in the cell cycle variance after shock. Two to 3 days after heat shock the proliferation rate decreased and then recovered. During the 6 days after heat shock, total protein synthesis was lower compared to the untreated cultures. The synthesis of heat shock proteins (100, 90, 84, 70, 68 kDa and some of lower MW) reached a maximum 6 h after heat shock. Parallel changes in the phosphorylation state of proteins were observed in an in vitro assay. Four proteins (100, 89, 67, and 15 kDa) increased and two proteins (97, 73 kDa) decreased their phosphorylation state significantly. Six days after heat shock two proteins (89, 55 kDa) increased their phosphorylation state; the 55-kDa phosphoprotein was identified as tubulin. The effect of heat shock on the intracellular calcium level was determined by measuring Fura 2 fluorescence. Six hours after shock, the Ca2+ level increased to a maximum (about three times the control value) and then dropped during the following days below the control values. We conclude from these results that a decrease in the calcium level may be causally involved in the differentiation process. The calcium effect is probably mediated by changes in the activity of different kinases. This assumption is compatible with the results of experiments with cyclic nucleotides when 10(-5) M cAMP and cGMP were added to in vitro assays of protein phosphorylation. They had different stimulating effects in heat-shocked, differentiating, and growing (control) cells.

The safety and effectiveness profile of eldecalcitol in a prospective, post-marketing observational study in Japanese patients with osteoporosis: interim report.

PubMed

Saito, Hitoshi; Kakihata, Hiroyuki; Nishida, Yosuke; Yatomi, Sawako; Nihojima, Shigeru; Kobayashi, Yumiko; Tabata, Hidehiro; Nomura, Makoto

2017-07-01

This large-scale post-marketing surveillance study was conducted to assess the safety and effectiveness of eldecalcitol treatment in patients with osteoporosis in a Japanese clinical setting. A total of 3567 patients with osteoporosis were enrolled and received eldecalcitol 0.75 μg/day for 12 months. For this interim report, 3285 patients were eligible for analysis. Mean age was 74.9 ± 8.7 years; 86.8 % (2854/3285) were women. There were 142 reported adverse drug reactions (ADRs) in 129 patients (3.92 % of the total 3285 patients): the most common were hypercalcemia and increased blood calcium (0.88 %), renal impairment (0.27 %), abdominal discomfort (0.24 %), constipation (0.24 %), and pruritus (0.24 %). The incidence of ADRs was 5.10 % in men and 3.74 % in women. Although 10 serious ADRs were reported in 9 patients (0.27 %), no clinically significant safety issues were identified. Incidence of hypercalcemia or increased blood calcium was 8.47 % in patients with renal impairment and only 0.74 % in patients without renal impairment. At last observation, the incidence of new vertebral and nonvertebral fractures was 2.44 % and 1.70 %, respectively. There was a significant increase in bone mineral density at the lumbar spine and distal radius. The bone turnover markers BAP, serum NTX, urinary NTX, and TRACP-5b were suppressed by eldecalcitol treatment in both sexes. In conclusion, consistent with the findings of the phase III pivotal clinical trial, eldecalcitol was shown to have a favorable safety profile and effectiveness in Japanese patients with osteoporosis. However, periodic measurements of serum calcium were required to prevent occurrence of hypercalcemia during eldecalcitol treatment, especially in patients with renal impairment.

Food habits related to osteoporosis in women in iran.

PubMed

Rafraf, Maryam; Bazyun, Behnaz

2011-01-01

Osteoporosis is an important public health problem. The aim of this study was to investigate food habits and some factors related to osteoporosis in women in Iran. This cross-sectional study was conducted on 399 childbearing age women who were attending health centers and 200 healthcare providers in 2007. Food habits and dietary calcium intake was evaluated by food frequency questionnaire and 24-hour recall method. Weight and height of subjects were also measured. Independent t-test, Mann-withney U test, Pearson, Spearman and Partial correlation coefficient tests were used for analyzing of data. Two groups of women had calcium intake deficiency. Daily frequency of milk, cheese, fruit and coffee consumptions in healthcare providers (0.82±0.82, 0.94±0.49, 2.01±1.28 and 0.84±2.05, P<0.02)  were significantly higher than those of women attending health centers(0.58±0.72, 0.84±0.32, 1.50±0.99 and 0.48±1.25).  Mean frequency use of dark vegetables, cola and pickles were significantly (P<0.004) higher in women who attending health centers (0.67±0.50, 1.55±2.36 and 1.92±2.03) than those of the other group (0.50±0.44, 1.09±2.65 and 1.49±1.72). In women who were attending health centers, negative and posi-tive significant relationship was found between daily calcium intake with age (P<0.04) and educational level (P<0.001). No significant relationship was found between body mass index with studied variables. Women of health care providers had healthier food habits compared to women who attending health centers. Educational programs are suggested to improve food habits among women to prevent osteoporosis in later life.

Intakes of Vitamins and Minerals in Relation to Urinary Incontinence, Voiding, and Storage Symptoms in Women: A Cross-Sectional Analysis from the Boston Area Community Health Survey

PubMed Central

Maserejian, Nancy N.; Giovannucci, Edward L.; McVary, Kevin T.; McKinlay, John B.

2011-01-01

Background Whether lower urinary tract symptoms (LUTS), including voiding, storage, and urinary incontinence, are affected by dietary micronutrients is uncertain. Objective To test the hypothesis that carotenoid, vitamin C, zinc, and calcium intakes are associated with LUTS and urinary incontinence in women. Design, setting, and participants During an observational, cross-sectional, population-based epidemiologic study of 2060 women (30–79 yr of age) in the Boston Area Community Health (BACH) survey (2002–2005), data were collected by validated food frequency questionnaire and in-person interviews and analyzed using multivariate regression. Measurements LUTS, storage, and voiding symptoms were assessed using the American Urological Association Symptom Index (AUASI) and a validated severity index for urinary incontinence. Results and limitations Women who consumed high-dose vitamin C from diet and supplements were more likely to report storage symptoms, especially combined frequency and urgency (>500 vs <50 mg/d; odds ratio [OR]: 3.42; 95% confidence interval [CI], 1.44–8.12). However, greater consumption of dietary vitamin C or β-cryptoxanthin was inversely associated with voiding symptoms (ptrend < 0.01). Both dietary and supplemental calcium were positively associated with storage symptoms (eg, supplement >1000 mg/d vs none; OR: 2.04; 95% CI, 1.35–3.09; ptrend = 0.0002). No consistent associations were observed for β-carotene, lycopene, or other carotenoids, although smokers using β-carotene supplements were more likely to report storage problems. Whether the observed associations represent direct causes of diet on LUTS is uncertain. Conclusions High-dose intakes of vitamin C and calcium were positively associated with urinary storage or incontinence, whereas vitamin C and β-cryptoxanthin from foods and beverages were inversely associated with voiding symptoms. Results indicate that micronutrient intakes may contribute to LUTS in dose-dependent and symptom-specific ways. Further study is needed to confirm these findings and their relevance to clinical treatment decisions. PMID:21444148

Bone Parameters and Risk of Hip and Femur Fractures in Patients on Hemodialysis

PubMed Central

Hazzan, Azzour D.; Jhaveri, Kenar D.; Ma, Lin; Lacson, Eduardo

2016-01-01

Background and objectives Patients on hemodialysis have a high rate of hip fractures. In this study, we performed a contemporary analysis of mineral and bone parameters and their relationship to hip and femur fracture risk. Design, setting, participants, & measurements Patients on hemodialysis treated between 2000 and 2013 in Fresenius Medical Care North America facilities were included. Predictors were on the basis of data as of December 31 of each baseline year and time-averaged values of selected laboratory parameters and medication doses throughout the year. Four period cohorts were constructed from baseline years: 2000, 2003, 2006, and 2009. Follow-up for each cohort was ≤3 years. Results The incidence of hip and femur fractures remained generally unchanged (P=0.40), except among patients who were white and >65 years of age, in whom the rate decreased significantly over the 14-year period (P<0.01). Results from combined multivariable models indicated that the lowest quartiles of time–averaged intact parathyroid hormone were independently associated with higher hip fracture risk (intact parathyroid hormone =181–272 pg/ml: hazard ratio, 1.20; 95% confidence interval [95% CI], 1.03 to 1.41 and intact parathyroid hormone <181 pg/ml: hazard ratio, 1.20; 95% CI, 1.01 to 1.44; referent third quartile, 273 to <433 pg/ml). The lowest quartile of time–averaged serum calcium was also associated with higher risk (calcium <8.7 mg/dl; hazard ratio, 1.17; 95% CI, 1.00 to 1.37) compared with the referent third quartile of 9.1 to <9.5 mg/dl. Conclusions We found an association between lower levels of intact parathyroid hormone and serum calcium and greater risk for hip and femur fractures among patients on hemodialysis. These findings support additional research toward elucidating long-term safety of treatment approaches for hyperparathyroidism in patients with ESRD. PMID:27026521

Evaluation of dietary intake of vitamins and minerals in 13-15-years-old boys from a sport school in Warsaw.

PubMed

Szczepańska, Beata; Malczewska-Lenczowska, Jadwiga; Wajszczyk, Bożena

2016-01-01

Insufficient intake of vitamins and minerals, in teenagers engaged in physical activity increases the risk of health disorders. The aim of this study was to evaluate selected vitamins and minerals intake in 13-15-year-old boys from sport school. The study of dietary intake was conducted among 44 boys from the School of Sport Championship (SSC). Nutritional data was collected using 24-hour recall for 3 days of week. Daily intake of minerals: sodium, potassium, calcium, phosphorus, magnesium, iron, zinc, copper, iodine and vitamins: A, E, D, B1, B2, B6, B12, C, folate and niacin was estimated. The probability of insufficient intake of nutrients in relation to the standard levels: Estimated Average Requirement (EAR) or Adequate Intake (AI) as well as excessive intake of them in relation to the Tolerable Upper Intake Level (UL) were assessed. The highest percentage of insufficient intake concerned vitamin D (100%), potassium (69%), folate (53%), and calcium (50%), slightly lower of magnesium (27%), vitamins C (24%) and E (15%). The risk of inadequate intake of other minerals: sodium, copper, iron, zinc, phosphorus, iodine and vitamins: B6, B1, B2, A, B12, niacin, was relatively lower and amounted from 0.3% to 5.4%. The disturbingly high probability of exceeding the UL for sodium (99.5%) was observed. A significant disproportion between the mean intake and the percentage of inadequate diets indicates a large diversity in the intake of vitamins and minerals in the group of studied boys, what was the reason of unbalanced diet. The insufficient intake concerns especially vitamin D, potassium, folate, calcium and a lesser extent magnesium, vitamins C and E. Sodium intake was disturbingly high. In order to avoid nutritional mistakes in the future education on the rational nutrition among students, their parents, and teachers is necessary.

Coupled nitrogen and calcium cycles in forests of the Oregon Coast Range

USGS Publications Warehouse

Perakis, S.S.; Maguire, D.A.; Bullen, T.D.; Cromack, K.; Waring, R.H.; Boyle, J.R.

2006-01-01

Nitrogen (N) is a critical limiting nutrient that regulates plant productivity and the cycling of other essential elements in forests. We measured foliar and soil nutrients in 22 young Douglas-fir stands in the Oregon Coast Range to examine patterns of nutrient availability across a gradient of N-poor to N-rich soils. N in surface mineral soil ranged from 0.15 to 1.05% N, and was positively related to a doubling of foliar N across sites. Foliar N in half of the sites exceeded 1.4% N, which is considered above the threshold of N-limitation in coastal Oregon Douglas-fir. Available nitrate increased five-fold across this gradient, whereas exchangeable magnesium (Mg) and calcium (Ca) in soils declined, suggesting that nitrate leaching influences base cation availability more than soil parent material across our sites. Natural abundance strontium isotopes (87Sr/86Sr) of a single site indicated that 97% of available base cations can originate from atmospheric inputs of marine aerosols, with negligible contributions from weathering. Low annual inputs of Ca relative to Douglas-fir growth requirements may explain why foliar Ca concentrations are highly sensitive to variations in soil Ca across our sites. Natural abundance calcium isotopes (??44Ca) in exchangeable and acid leachable pools of surface soil measured at a single site showed 1 per mil depletion relative to deep soil, suggesting strong Ca recycling to meet tree demands. Overall, the biogeochemical response of these Douglas-fir forests to gradients in soil N is similar to changes associated with chronic N deposition in more polluted temperate regions, and raises the possibility that Ca may be deficient on excessively N-rich sites. We conclude that wide gradients in soil N can drive non-linear changes in base-cation biogeochemistry, particularly as forests cross a threshold from N-limitation to N-saturation. The most acute changes may occur in forests where base cations are derived principally from atmospheric inputs. ?? 2006 Springer Science+Business Media, Inc.

Alkaline-earth metal carboxylates characterized by 43Ca and 87Sr solid-state NMR: impact of metal-amine bonding.

PubMed

Burgess, Kevin M N; Xu, Yang; Leclerc, Matthew C; Bryce, David L

2014-01-06

A series of calcium and strontium complexes featuring aryl carboxylate ligands has been prepared and characterized by alkaline-earth ((43)Ca and (87)Sr) solid-state NMR experiments in a magnetic field of 21.1 T. In the 11 compounds studied as part of this work, a range of coordination motifs are observed including nitrogen atom binding to Ca(2+) and Sr(2+), a binding mode which has not been investigated previously by (43)Ca or (87)Sr solid-state NMR. (43)Ca isotopic enrichment has enabled the full characterization of the (43)Ca electric field gradient (EFG) and chemical shift tensors of the two calcium sites in calcium p-aminosalicylate (Ca(pams)), where both NMR interactions are affected by the presence of a nitrogen atom in the first coordination sphere of one of the metal sites. The (43)Ca isotropic chemical shift is sensitive to the Ca-N distance as exemplified by the NMR parameters of a second form of Ca(pams) and density functional theory (DFT) calculations. Studies of the strontium analogue, Sr(pams), confirm a similar sensitivity of the (87)Sr EFG tensor to the presence or absence of nitrogen in the first coordination sphere. To our knowledge, this is the first systematic (87)Sr NMR study of strontium complexes featuring organic ligands. The |CQ((87)Sr)| values are found to be sensitive to the coordination number about Sr(2+). In general, this work has also established a larger data set of reliable experimental |CQ((43)Ca)| values which correlate well with those obtained using gauge-including projector-augmented-wave (GIPAW) DFT calculations. It is found that the use of a recently recommended quadrupole moment for (43)Ca, -44.4 mbarn, improves the agreement with experimental values. This contribution lays the groundwork for the interpretation of (43)Ca and (87)Sr NMR spectra of more challenging systems, particularly where nitrogen-alkaline earth metal bonding is occurring.

Biofilm-induced calcium carbonate precipitation: application in the subsurface

NASA Astrophysics Data System (ADS)

Phillips, A. J.; Eldring, J.; Lauchnor, E.; Hiebert, R.; Gerlach, R.; Mitchell, A. C.; Esposito, R.; Cunningham, A. B.; Spangler, L.

2012-12-01

We have investigated mitigation strategies for sealing high permeability regions, like fractures, in the subsurface. This technology has the potential to, for example, improve the long-term security of geologically-stored carbon dioxide (CO2) by sealing fractures in cap rocks or to mitigate leakage pathways to prevent contamination of overlying aquifers from hydraulic fracturing fluids. Sealing technologies using low-viscosity fluids are advantageous since they potentially reduce the necessary injection pressures and increase the radius of influence around injection wells. In this technology, aqueous solutions and suspensions are used to promote microbially-induced mineral precipitation which can be applied in subsurface environments. To this end, a strategy was developed to twice seal a hydraulically fractured, 74 cm (2.4') diameter Boyles Sandstone core, collected in North-Central Alabama, with biofilm-induced calcium carbonate (CaCO3) precipitates under ambient pressures. Sporosarcina pasteurii biofilms were established and calcium and urea containing reagents were injected to promote saturation conditions favorable for CaCO3 precipitation followed by growth reagents to resuscitate the biofilm's ureolytic activity. Then, in order to evaluate this process at relevant deep subsurface pressures, a novel high pressure test vessel was developed to house the 74 cm diameter core under pressures as high as 96 bar (1,400 psi). After determining that no impact to the fracture permeability occurred due to increasing overburden pressure, the fractured core was sealed under subsurface relevant pressures relating to 457 meters (1,500 feet) below ground surface (44 bar (650 psi) overburden pressure). After fracture sealing under both ambient and subsurface relevant pressure conditions, the sandstone core withstood three times higher well bore pressure than during the initial fracturing event, which occurred prior to biofilm-induced CaCO3 mineralization. These studies suggest biofilm-induced CaCO3 precipitation technologies may potentially seal and strengthen high permeability regions or fractures (either natural or induced) in the subsurface. Novel high pressure test vessel to investigate biogeochemical processes under relevant subsurface scales and pressures.

The efficacy of using exogenous enzymes cocktail on production, egg quality, egg nutrients and blood metabolites of laying hens fed distiller's dried grains with solubles.

PubMed

Abd El-Hack, M E; Chaudhry, M T; Mahrose, K M; Noreldin, A; Emam, M; Alagawany, M

2018-04-01

An experiment was performed using 120 Hisex Brown laying hens for evaluating the effects of different inclusion levels of corn distiller's dried grains with solubles (DDGS) as a replacement of soybean meal (SBM) with or without enzyme cocktail on performance, egg quality, egg nutrients and blood metabolites in laying hens through 22-42 weeks of age. A 4 × 2 factorial design experiment was performed including four substitution levels of DDGS (0, 250, 500 and 750 g/kg respectively) and two enzyme cocktail levels (0 and 250 mg/kg diet). The used enzyme in this study "Gallazyme" composed of xylanase, Trichoderma longibrachiatum (600 units/g), protease, Bacillus subtilis (8,000 units/g) and amylase and Bacillus amyloliquofaciens (800 units/g). The control diet showed the best feed efficiency followed by the intermediate levels of DDGS. The lowest value of feed efficiency was found in the group fed the highest level of DDGS. Enzyme addition improved feed efficiency and decreased laying rate. Increasing DDGS levels was associated with albumin and shell thickness increases. Dietary DDGS depressed all egg components except the organic matter which maximised in enzyme-treated groups. Increasing DDGS level was accompanied by increase in yolk cholesterol and total lipids. No significant impacts were detected with enzymes supplementation on yolk lipids profile. Excepting serum calcium and phosphorous, all serum constituents increased with increasing level of DDGS. Using enzyme markedly depressed serum ammonia by 15.02% and increased calcium by 6.44% compared with enzyme-free diets. Interaction between DDGS and enzyme was significant on most of studied parameters. It could be concluded that using enzyme cocktail in DDGS-based diets may improve feed efficiency and egg quality, in addition to lowering blood ammonia and increasing blood calcium. It is recommended to substitute SBM by DDGS up to 500 g/kg diet. © 2017 Blackwell Verlag GmbH.

Calcium phosphate coupled Newcastle disease vaccine elicits humoral and cell mediated immune responses in chickens.

PubMed

Koppad, Sanganagouda; Raj, G Dhinakar; Gopinath, V P; Kirubaharan, J John; Thangavelu, A; Thiagarajan, V

2011-12-01

Calcium phosphate (CaP) particles were coupled with inactivated Newcastle disease virus (NDV) vaccine. The surface morphology of CaP particles coupled to NDV was found to be spherical, smooth and with a tendency to agglomerate. The mean (± SE) size of CaP particles was found 557.44 ± 18.62 nm. The mean percent encapsulation efficiency of CaP particles coupled to NDV assessed based on total protein content and haemagglutination (HA) activity in eluate was found to be 10.72 ± 0.89 and 12.50 ± 2.09, respectively. The humoral and cell mediated immune responses induced by CaP coupled NDV vaccine were assessed in comparison to a commercial live vaccine (RDV 'F'). CaP coupled NDV vaccine elicited prolonged haemagglutination inhibition (HI) and enzyme linked immunosorbent assay (ELISA) titres in the serum even at fourth and fifth week post-vaccination (PV), unlike RDV 'F' inoculated chickens whose titres declined to insignificant levels by this time. CaP coupled NDV vaccine could stimulate HI antibodies in tracheal washings and tears from second and first week PV, respectively. IgA ELISA antibodies were also seen in tracheal washings of these birds from third week PV and in tears from second week PV. CaP coupled NDV vaccine elicited cell mediated immune responses (CMI) from two to four weeks PV. The stimulation indices obtained after stimulation with specific antigen was not significantly different between CaP coupled antigen and live NDV virus except on first week PV. However, CaP coupled antigen did not cause suppression of lympo proliferation as indicated by statistically similar responses to mitogen, concanavalin A between the two groups. Overall, CaP coupled NDV vaccine elicited stronger and prolonged immune responses in comparison to the commercial live vaccine. No increase in the serum calcium and phosphorous levels were seen in CaP coupled NDV vaccine inoculated chickens. Copyright © 2010 Elsevier Ltd. All rights reserved.

Beneficial effects of calcitriol on hypertension, glucose intolerance, impairment of endothelium-dependent vascular relaxation, and visceral adiposity in fructose-fed hypertensive rats.

PubMed

Chou, Chu-Lin; Pang, Cheng-Yoong; Lee, Tony J F; Fang, Te-Chao

2015-01-01

Besides regulating calcium homeostasis, the effects of vitamin D on vascular tone and metabolic disturbances remain scarce in the literature despite an increase intake with high-fructose corn syrup worldwide. We investigated the effects of calcitriol, an active form of vitamin D, on vascular relaxation, glucose tolerance, and visceral fat pads in fructose-fed rats. Male Wistar-Kyoto rats were divided into 4 groups (n = 6 per group). Group Con: standard chow diet for 8 weeks; Group Fru: high-fructose diet (60% fructose) for 8 weeks; Group Fru-HVD: high-fructose diet as Group Fru, high-dose calcitriol treatment (20 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding; and Group Fru-LVD: high-fructose diet as Group Fru, low-dose calcitriol treatment (10 ng / 100 g body weight per day) 4 weeks after the beginning of fructose feeding. Systolic blood pressure was measured twice a week by the tail-cuff method. Blood was examined for serum ionized calcium, phosphate, creatinine, glucose, triglycerides, and total cholesterol. Intra-peritoneal glucose intolerance test, aortic vascular reactivity, the weight of visceral fat pads, adipose size, and adipose angiotensin II levels were analyzed at the end of the study. The results showed that the fructose-fed rats significantly developed hypertension, impaired glucose tolerance, heavier weight and larger adipose size of visceral fat pads, and raised adipose angiotensin II expressions compared with the control rats. High- and low-dose calcitriol reduced modestly systolic blood pressure, increased endothelium-dependent aortic relaxation, ameliorated glucose intolerance, reduced the weight and adipose size of visceral fat pads, and lowered adipose angiotensin II expressions in the fructose-fed rats. However, high-dose calcitriol treatment mildly increased serum ionized calcium levels (1.44 ± 0.05 mmol/L). These results suggest a protective role of calcitriol treatment on endothelial function, glucose tolerance, and visceral adiposity in fructose-fed rats.

Impact of Calcium Intake and Intestinal Calcium Absorption on Kidney Stones in Older Women: The Study of Osteoporotic Fractures (SOF)

PubMed Central

Sorensen, Mathew D.; Eisner, Brian H.; Stone, Katie L.; Kahn, Arnold J.; Lui, Li-Yung; Sadetsky, Natalia; Stoller, Marshall L.

2013-01-01

Purpose Intestinal calcium absorption is thought to play a critical role in nephrolithiasis; however, no study has directly assessed this association. The purpose of this study was to explore the relationship between intestinal fractional calcium absorption, calcium intake, and nephrolithiasis. Materials and Methods The Study of Osteoporotic Fractures is a prospective cohort of 9704 post-menopausal women recruited from population-based listings in 1986 and followed for more than 20 years. Secondary analyses were performed of 7982 women who reported their history of nephrolithiasis, of which 5452 (68%) underwent oral radioactive calcium assay (45Ca). The impact of dietary and supplemental calcium on intestinal fractional calcium absorption was evaluated and factors independently associated with nephrolithiasis were determined. Results Fractional calcium absorption decreased with increased calcium intake, with no difference between dietary and supplemental calcium. Fractional calcium absorption was higher in women with a nephrolithiasis history among all calcium intake groups. Increased dietary calcium intake reduced the likelihood of nephrolithiasis by 45–54% (p=0.03). Women with a history of nephrolithiasis were less likely to supplement calcium (p<0.001). In adjusted analyses, women who supplemented calcium were 21–38% less likely to have a nephrolithiasis history (p=0.007) and there was a 24% increased risk of kidney stones for each 10% increase in fractional calcium absorption (p=0.008). Conclusions Fractional calcium absorption is higher in women with a history of nephrolithiasis. Higher intestinal fractional calcium absorption is associated with a greater risk of historic nephrolithiasis. Dietary and supplemental calcium decrease fractional calcium absorption and may protect against nephrolithiasis. PMID:22341269

Impact of calcium intake and intestinal calcium absorption on kidney stones in older women: the study of osteoporotic fractures.

PubMed

Sorensen, Mathew D; Eisner, Brian H; Stone, Katie L; Kahn, Arnold J; Lui, Li-Yung; Sadetsky, Natalia; Stoller, Marshall L

2012-04-01

Intestinal calcium absorption is thought to have a critical role in nephrolithiasis. However, to our knowledge no study has directly assessed this association. Therefore, we explored the relationship among intestinal fractional calcium absorption, calcium intake and nephrolithiasis. The Study of Osteoporotic Fractures is a prospective cohort of 9,704 postmenopausal women recruited from population based listings in 1986 and followed for more than 20 years. Secondary analyses were performed of 7,982 women who reported their history of nephrolithiasis, of which 5,452 (68%) underwent an oral radioactive calcium assay (45Ca). The impact of dietary and supplemental calcium on intestinal fractional calcium absorption was evaluated, and factors independently associated with nephrolithiasis were determined. Fractional calcium absorption decreased with increased calcium intake, with no difference between dietary and supplemental calcium. Fractional calcium absorption was higher in women with a nephrolithiasis history among all calcium intake groups. Increased dietary calcium intake reduced the likelihood of nephrolithiasis by 45% to 54% (p=0.03). Women with a history of nephrolithiasis were less likely to supplement calcium (p<0.001). In adjusted analyses women who supplemented calcium were 21% to 38% less likely to have a nephrolithiasis history (p=0.007) and there was a 24% increased risk of kidney stones for each 10% increase in fractional calcium absorption (p=0.008). Fractional calcium absorption is higher in women with a history of nephrolithiasis. Higher intestinal fractional calcium absorption is associated with a greater risk of historical nephrolithiasis. Dietary and supplemental calcium decrease fractional calcium absorption, and may protect against nephrolithiasis. Copyright © 2012 American Urological Association Education and Research, Inc. Published by Elsevier Inc. All rights reserved.

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

PubMed

Graveland, J; Berends, A E

1997-01-01

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.

Calcium metabolism in health and disease.

PubMed

Peacock, Munro

2010-01-01

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

[The fasting calcium/creatinine ratio in patients with calcium stones and the relation with hypercalciuria and phosphocalcium metabolism].

PubMed

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

2016-04-01

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/ creatinine<0.11); Group 2: 77 patients (calcium/ creatinine>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.

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.

PubMed

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

2017-11-08

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.

Calcium isotopic fractionation in mantle peridotites by melting and metasomatism and Ca isotope composition of the Bulk Silicate Earth

NASA Astrophysics Data System (ADS)

Kang, Jin-Ting; Ionov, Dmitri A.; Liu, Fang; Zhang, Chen-Lei; Golovin, Alexander V.; Qin, Li-Ping; Zhang, Zhao-Feng; Huang, Fang

2017-09-01

To better constrain the Ca isotopic composition of the Bulk Silicate Earth (BSE) and explore the Ca isotope fractionation in the mantle, we determined the Ca isotopic composition of 28 peridotite xenoliths from Mongolia, southern Siberia and the Siberian craton. The samples are divided in three chemical groups: (1) fertile, unmetasomatized lherzolites (3.7-4.7 wt.% Al2O3); (2) moderately melt-depleted peridotites (1.3-3.0 wt.% Al2O3) with no or very limited metasomatism (LREE-depleted cpx); (3) strongly metasomatized peridotites (LREE-enriched cpx and bulk rock) further divided in subgroups 3a (harzburgites, 0.1-1.0% Al2O3) and 3b (fertile lherzolites, 3.9-4.3% Al2O3). In Group 1, δ44/40Ca of fertile spinel and garnet peridotites, which experienced little or no melting and metasomatism, show a limited variation from 0.90 to 0.99‰ (relative to SRM 915a) and an average of 0.94 ± 0.05‰ (2SD, n = 14), which defines the Ca isotopic composition of the BSE. In Group 2, the δ44/40Ca is the highest for three rocks with the lowest Al2O3, i.e. the greatest melt extraction degrees (average 1.06 ± 0.04 ‰, i.e. ∼0.1‰ heavier than the BSE estimate). Simple modeling of modal melting shows that partial melting of the BSE with 103 ln ⁡αperidotite-melt ranging from 0.10 to 0.25 can explain the Group 2 data. By contrast, δ44/40Ca in eight out of nine metasomatized Group 3 peridotites are lower than the BSE estimate. The Group 3a harzburgites show the greatest δ44/40Ca variation range (0.25-0.96‰), with δ44/40Ca positively correlated with CaO and negatively correlated with Ce/Eu. Chemical evidence suggests that the residual, melt-depleted, low-Ca protoliths of the Group 3a harzburgites were metasomatized, likely by carbonate-rich melts/fluids. We argue that such fluids may have low (≤0.25‰) δ44/40Ca either because they contain recycled crustal components or because Ca isotopes, similar to trace elements and their ratios, may be fractionated by kinetic and/or chromatographic effects of melt percolation in the mantle. The δ44/40Ca in Group 3b lherzolites (0.83-0.89‰) are lower than in the BSE as well, but the effects of metasomatism on δ44/40Ca are smaller, possibly because of the high Ca contents in their protoliths and/or smaller δ44/40Ca differences between the protoliths and metasomatic agents. The BSE estimates based on fertile peridotites in this study fall in the δ44/40Ca ranges for oceanic and continental basalts, various meteorites (achondrites; carbonaceous, ordinary and enstatite chondrites), Mars, and the Moon. These results provide benchmarks for the application of Ca isotopes to planet formation, mantle evolution, and crustal recycling.

Mineral deposition in bacteria-filled and bacteria-free calcium bodies in the crustacean Hyloniscus riparius (Isopoda: Oniscidea).

PubMed

Vittori, Miloš; Rozman, Alenka; Grdadolnik, Jože; Novak, Urban; Štrus, Jasna

2013-01-01

Crustacean calcium bodies are epithelial sacs which contain a mineralized matrix. The objectives of this study were to describe the microscopic anatomy of calcium bodies in the terrestrial isopod Hyloniscus riparius and to establish whether they undergo molt-related structural changes. We performed 3D reconstruction of the calcium bodies from paraffin sections and analyzed their structure with light and electron microscopy. In addition, we analyzed the chemical composition of their mineralized matrices with micro-Raman spectroscopy. Two pairs of these organs are present in H. riparius. One pair is filled with bacteria while the other pair is not. In non-molting animals, the bacteria-filled calcium bodies contain apatite crystals and the bacteria-free calcium bodies enclose CaCO3-containing concretions with little organic matrix. During preparation for molt, an additional matrix layer is deposited in both pairs of calcium bodies. In the bacteria-filled calcium bodies it contains a mixture of calcium carbonate and calcium phosphate, whereas only calcium carbonate is present in bacteria-free calcium bodies. After ecdysis, all mineral components in bacteria-free calcium bodies and the additional matrix layer in bacteria-filled calcium bodies are completely resorbed. During calcium resorption, the apical surface of the calcium body epithelium is deeply folded and electron dense granules are present in spaces between epithelial cells. Our results indicate that the presence of bacteria might be linked to calcium phosphate mineralization. Calcium bodies likely provide a source of calcium and potentially phosphate for the mineralization of the new cuticle after molt. Unlike other terrestrial isopods, H. riparius does not form sternal CaCO3 deposits and the bacteria-free calcium bodies might functionally replace them in this species.

Ryanodine receptor gating controls generation of diastolic calcium waves in cardiac myocytes

PubMed Central

Petrovič, Pavol; Valent, Ivan; Cocherová, Elena; Pavelková, Jana

2015-01-01

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

Mineral Deposition in Bacteria-Filled and Bacteria-Free Calcium Bodies in the Crustacean Hyloniscus riparius (Isopoda: Oniscidea)

PubMed Central

Vittori, Miloš; Rozman, Alenka; Grdadolnik, Jože; Novak, Urban; Štrus, Jasna

2013-01-01

Crustacean calcium bodies are epithelial sacs which contain a mineralized matrix. The objectives of this study were to describe the microscopic anatomy of calcium bodies in the terrestrial isopod Hyloniscus riparius and to establish whether they undergo molt-related structural changes. We performed 3D reconstruction of the calcium bodies from paraffin sections and analyzed their structure with light and electron microscopy. In addition, we analyzed the chemical composition of their mineralized matrices with micro-Raman spectroscopy. Two pairs of these organs are present in H. riparius. One pair is filled with bacteria while the other pair is not. In non-molting animals, the bacteria-filled calcium bodies contain apatite crystals and the bacteria-free calcium bodies enclose CaCO3-containing concretions with little organic matrix. During preparation for molt, an additional matrix layer is deposited in both pairs of calcium bodies. In the bacteria-filled calcium bodies it contains a mixture of calcium carbonate and calcium phosphate, whereas only calcium carbonate is present in bacteria-free calcium bodies. After ecdysis, all mineral components in bacteria-free calcium bodies and the additional matrix layer in bacteria-filled calcium bodies are completely resorbed. During calcium resorption, the apical surface of the calcium body epithelium is deeply folded and electron dense granules are present in spaces between epithelial cells. Our results indicate that the presence of bacteria might be linked to calcium phosphate mineralization. Calcium bodies likely provide a source of calcium and potentially phosphate for the mineralization of the new cuticle after molt. Unlike other terrestrial isopods, H. riparius does not form sternal CaCO3 deposits and the bacteria-free calcium bodies might functionally replace them in this species. PMID:23554963

Mammary-Specific Ablation of the Calcium-Sensing Receptor During Lactation Alters Maternal Calcium Metabolism, Milk Calcium Transport, and Neonatal Calcium Accrual

PubMed Central

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

2013-01-01

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

Fast Kinetics of Calcium Signaling and Sensor Design

PubMed Central

Tang, Shen; Reddish, Florence; Zhuo, You; Yang, Jenny J.

2015-01-01

Fast calcium signaling is regulated by numerous calcium channels exhibiting high spatiotemporal profiles which are currently measured by fluorescent calcium sensors. There is still a strong need to improve the kinetics of genetically encoded calcium indicators (sensors) to capture calcium dynamics in the millisecond time frame. In this review, we summarize several major fast calcium signaling pathways and discuss the recent developments and application of genetically encoded calcium indicators to detect these pathways. A new class of genetically encoded calcium indicators designed with site-directed mutagenesis on the surface of beta-barrel fluorescent proteins to form a pentagonal bipyramidal-like calcium binding domain dramatically accelerates calcium binding kinetics. Furthermore, novel genetically encoded calcium indicators with significantly increased fluorescent lifetime change are advantageous in deep-field imaging with high light-scattering and notable morphology change. PMID:26151819

Oral calcium carbonate affects calcium but not phosphorus balance in stage 3-4 chronic kidney disease.

PubMed

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

2013-05-01

Patients with chronic kidney disease (CKD) are given calcium carbonate to bind dietary phosphorus, reduce phosphorus retention, and prevent negative calcium balance; however, data are limited on calcium and phosphorus balance during CKD to support this. Here, we studied eight patients with stage 3 or 4 CKD (mean estimated glomerular filtration rate 36 ml/min) who received a controlled diet with or without a calcium carbonate supplement (1500 mg/day calcium) during two 3-week balance periods in a randomized placebo-controlled cross-over design. All feces and urine were collected during weeks 2 and 3 of each balance period and fasting blood, and urine was collected at baseline and at the end of each week. Calcium kinetics were determined using oral and intravenous (45)calcium. Patients were found to be in neutral calcium and phosphorus balance while on the placebo. Calcium carbonate supplementation 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 soft-tissue deposition. Fasting blood and urine biochemistries of calcium and phosphate homeostasis were unaffected by calcium carbonate. Thus, the positive calcium balance produced by calcium carbonate treatment within 3 weeks cautions against its use as a phosphate binder in patients with stage 3 or 4 CKD, if these findings can be extrapolated to long-term therapy.

The contribution of diet and genotype to iron status in women: a classical twin study.

PubMed

Fairweather-Tait, Susan J; Guile, Geoffrey R; Valdes, Ana M; Wawer, Anna A; Hurst, Rachel; Skinner, Jane; Macgregor, Alexander J

2013-01-01

This is the first published report examining the combined effect of diet and genotype on body iron content using a classical twin study design. The aim of this study was to determine the relative contribution of genetic and environmental factors in determining iron status. The population was comprised of 200 BMI- and age-matched pairs of MZ and DZ healthy twins, characterised for habitual diet and 15 iron-related candidate genetic markers. Variance components analysis demonstrated that the heritability of serum ferritin (SF) and soluble transferrin receptor was 44% and 54% respectively. Measured single nucleotide polymorphisms explained 5% and selected dietary factors 6% of the variance in iron status; there was a negative association between calcium intake and body iron (p = 0.02) and SF (p = 0.04).

Cadmium contamination in cereal-based diets and diet ingredients

DOE Office of Scientific and Technical Information (OSTI.GOV)

Siitonen, P.H.; Thompson, H.C. Jr.

1990-11-01

Cereal-based diet and/or diet ingredient cadmium levels were determined by graphite furnace AAS. Cadmium contamination was 88.3 and 447 ppb in two cereal-based diets, 44.6 and 48.9 ppb in two purified diets, and ranged from less than 1.1 to 22,900 ppb in the ingredients of one cereal-based diet. The major source of cadmium contamination was attributed to the calcium supplement used for diet formulation. Comparative analyses of two purified diet samples and one cereal-based diet by the National Institute of Standards and Technology (NIST, formerly the National Bureau of Standards) and the National Center for Toxicological Research (NCTR) gave virtuallymore » identical results for Cd. A comparative study of Cd levels determined by flame and furnace AAS was also made by the NCTR and the NIST.« less

Global Distribution of Mercury's Neutrals from MESSENGER Measurements Combined with a Tomographic Method

NASA Technical Reports Server (NTRS)

Sarantos, Menelaos; McClintock, Bill; Vervack, Ron, Jr.; Killen, Rosemary; Merkel, Aimee; Slavin, James; Solomon, Sean C.

2011-01-01

The MErcury Surface, Space ENvironment, GEochemistry, and Ranging (MESSENGER) spacecraft entered orbit about Mercury on March 18, 2011. Since then, the Ultraviolet and Visible Spectrometer (UVVS) onboard this spacecraft has been observing Mercury's collisionless exosphere. We present measurements by MESSENGER UVVS of the sodium, calcium, and magnesium distributions that were obtained during multiple passes through the tail over a period of one month. Global maps of the exosphere were constructed daily from such measurements using a recently developed tomographic technique. During this period, Mercury moved towards the Sun from being about 0.44 astronomical units (AU) to approximately 0.32 AU from the Sun. Hence, our reconstructions provide information about the three-dimensional structure of the exosphere, the source processes for these species, and their dependence with orbital distance during the entire in-leg of Mercury's orbit.

Determination of cytoplasmic calcium concentration in Dryopteris spores: a developmentally non-disruptive technique for loading of the calcium indicator fura-2

NASA Technical Reports Server (NTRS)

Scheuerlein, R.; Schmidt, K.; Poenie, M.; Roux, S. J.

1991-01-01

Germination of Dryopteris spores is mediated by the physiologically active, far-red-absorbing form of phytochrome, Pfr, and external Ca2+ is necessary for the transduction of the light signal. Because knowledge about the cytoplasmic calcium ion concentration, [Ca2+]i, is of great importance for understanding the role of calcium during signal transduction, this value was measured using fura-2 in fern spores undergoing the normal developmental progression into germination. Fura-2 was loaded into the spores by electroporation, which does not disrupt the normal process of germination. The intensity of the fluorescence emission of the loaded fura-2 was analysed by a microspectrophotometric assay of single spores, and successful loading could be obtained by the application of ten electrical pulses (field strength 7.5 kV cm-1, half-life (time constant) 230 microseconds). Fura-2 was alternately excited by light of wavelengths 355 and 385 nm through an inverted fluorescence microscope, and the emitted fura-2 fluorescence was collected by a silicon-intensified video camera. The cytoplasmic calcium ion concentration was calculated from the ratio of the camera output obtained for both wavelengths and displayed by a pseudo-color technique. Spores responded to changes of the extracellular Ca2+ concentration, and this observation is considered as evidence that fura-2 is loaded into the cytoplasm. The substitution of a low external [Ca2+] (1 mM ethyleneglycol-bis(2-aminoethylether)-N,N,N',N'-tetraacetic acid (EGTA)) by 1 mM CaCl2 caused a fast increase of [Ca2+]i from approx. 50 nM to above 500 nM. In contrast, the subsequent substitution of CaCl2 by EGTA decreased [Ca2+]i again below 100 nM within 0.5 h. Furthermore, the application of ionomycin could initiate a change in [Ca2+]i according to the Ca2+ gradient established between the extracellular medium and cytoplasm. In spores sown on a Ca(2+) -free medium, [Ca2+]i, analysed in a buffer containing EGTA, was found to be around 50 nM during the first days of cultivation, independent of the irradiation protocol. However, if spores were grown in darkness on a Ca(2+) -containing medium and analysed in EGTA, [Ca2+]i was significantly higher (> or = 500 nM). In red-light-irradiated spores, [Ca2+]i was found to decrease with increasing time after irradiation, and was determined to be less than 100 nM when analysis was done 44 h after germination was initiated by the light treatment.

Genetically Encoded Calcium Indicators For Studying Long-Term Calcium Dynamics During Apoptosis

PubMed Central

Garcia, M. Iveth; Chen, Jessica J.; Boehning, Darren

2017-01-01

Intracellular calcium release is essential for regulating almost all cellular functions. Specific spatio-temporal patterns of cytosolic calcium elevations are critical determinants of cell fate in response to pro-apoptotic cellular stressors. As the apoptotic program can take hours or days, measurement of long-term calcium dynamics are essential for understanding the mechanistic role of calcium in apoptotic cell death. Due to the technical limitations of using calcium-sensitive dyes to measure cytosolic calcium little is known about long-term calcium dynamics in living cells after treatment with apoptosis-inducing drugs. Genetically encoded calcium indicators could potentially overcome some of the limitations of calcium-sensitive dyes. Here, we compared the performance of the genetically encoded calcium indicators GCaMP6s and GCaMP6f with the ratiometric dye Fura-2. GCaMP6s performed as well or better than Fura-2 in detecting agonist-induced calcium transients. We then examined the utility of GCaMP6s for continuously measuring apoptotic calcium release over the course of ten hours after treatment with staurosporine. We found that GCaMP6s was suitable for measuring apoptotic calcium release over long time courses and revealed significant heterogeneity in calcium release dynamics in individual cells challenged with staurosporine. Our results suggest GCaMP6s is an excellent indicator for monitoring long-term changes cytosolic calcium during apoptosis. PMID:28073595

Reduction of calcium flux from the extracellular region and endoplasmic reticulum by amorphous nano-silica particles owing to carboxy group addition on their surface.

PubMed

Onodera, Akira; Yayama, Katsutoshi; Morosawa, Hideto; Ishii, Yukina; Tsutsumi, Yasuo; Kawai, Yuichi

2017-03-01

Several studies have reported that amorphous nano-silica particles (nano-SPs) modulate calcium flux, although the mechanism remains incompletely understood. We thus analyzed the relationship between calcium flux and particle surface properties and determined the calcium flux route. Treatment of Balb/c 3T3 fibroblasts with nano-SPs with a diameter of 70 nm (nSP70) increased cytosolic calcium concentration, but that with SPs with a diameter of 300 or 1000 nm did not. Surface modification of nSP70 with a carboxy group also did not modulate calcium flux. Pretreatment with a general calcium entry blocker almost completely suppressed calcium flux by nSP70. Preconditioning by emptying the endoplasmic reticulum (ER) calcium stores slightly suppressed calcium flux by nSP70. These results indicate that nSP70 mainly modulates calcium flux across plasma membrane calcium channels, with subsequent activation of the ER calcium pump, and that the potential of calcium flux by nano-SPs is determined by the particle surface charge.

Calcium-regulated in vivo protein phosphorylation in Zea mays L. root tips

NASA Technical Reports Server (NTRS)

Raghothama, K. G.; Reddy, A. S.; Friedmann, M.; Poovaiah, B. W.

1987-01-01

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.

Diagnosis and assessment of skeletal related disease using calcium 41

DOEpatents

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

2012-05-15

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.

Diagnosis and assessment of skeletal related disease using calcium 41

DOEpatents

Hillegonds, Darren J.; Vogel, John S.; Fitzgerald, Robert L.; Deftos, Leonard J.; Herold, David; Burton, Douglas W.

2013-03-05

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.

Bioaccessibility of four calcium sources in different whey-based dairy matrices assessed by in vitro digestion.

PubMed

Lorieau, Lucie; Le Roux, Linda; Gaucheron, Frédéric; Ligneul, Amandine; Hazart, Etienne; Dupont, Didier; Floury, Juliane

2018-04-15

Numerous calcium sources are available to enrich food, but their behavior during digestion is still unknown. This study focused on the influence of the gastro-intestinal pH, the food structure and the calcium source on the bioaccessibility of the nutrient. Four calcium sources were studied: calcium carbonate, calcium citrate malate, calcium phosphate and calcium bisglycinate. These were added to dairy matrices, containing cream and whey proteins, of different forms (liquid or gel). The kinetics of solubility and ionic calcium concentration during in vitro digestion were studied, as function of gastro-intestinal pH. All calcium sources were almost fully soluble in the gastric compartment, and then became insoluble in the intestinal phase. The level of calcium insolubilisation in the intestinal phase was not significantly influenced by the matrix structure (liquid or gel), but was more dependent on the calcium source, this effect leading to different final calcium bioaccessibility from 36% to 20%. Copyright © 2017 Elsevier Ltd. All rights reserved.

The effect of habitat geology on calcium intake and calcium status of wild rodents.

PubMed

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

1991-12-01

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.

Calcium signaling in taste cells: regulation required.

PubMed

Medler, Kathryn F

2010-11-01

Peripheral taste receptor cells depend on distinct calcium signals to generate appropriate cellular responses that relay taste information to the central nervous system. Some taste cells have conventional chemical synapses and rely on calcium influx through voltage-gated calcium channels. Other taste cells lack these synapses and depend on calcium release from stores to formulate an output signal through a hemichannel. Despite the importance of calcium signaling in taste cells, little is known about how these signals are regulated. This review summarizes recent studies that have identified 2 calcium clearance mechanisms expressed in taste cells, including mitochondrial calcium uptake and sodium/calcium exchangers (NCXs). These studies identified a unique constitutive calcium influx that contributes to maintaining appropriate calcium homeostasis in taste cells and the role of the mitochondria and exchangers in this process. The additional role of NCXs in the regulation of evoked calcium responses is also discussed. Clearly, calcium signaling is a dynamic process in taste cells and appears to be more complex than has previously been appreciated.

Vitamin D Supplementation in Submariners

DTIC Science & Technology

2008-12-02

prevalence of over 10% in men.71 Most stones are composed of calcium oxalate or calcium phosphate.72 It is the composition of these stones that...urine that combine with calcium to form calcium oxalate stones.77 One of the major factors that reduce hyperoxaluria is calcium in the diet. The... calcium in the intestinal lumen forms insoluble calcium salts with the oxalates and is not absorbed. A diet low in calcium will allow more oxalates to be

Magnesium supplementation through seaweed calcium extract rather than synthetic magnesium oxide improves femur bone mineral density and strength in ovariectomized rats.

PubMed

Bae, Yun Jung; Bu, So Young; Kim, Jae Young; Yeon, Jee-Young; Sohn, Eun-Wha; Jang, Ki-Hyo; Lee, Jae-Cheol; Kim, Mi-Hyun

2011-12-01

Commercially available seaweed calcium extract can supply high amounts of calcium as well as significant amounts of magnesium and other microminerals. The purpose of this study was to investigate the degree to which the high levels of magnesium in seaweed calcium extract affects the calcium balance and the bone status in ovariectomized rats in comparison to rats supplemented with calcium carbonate and magnesium oxide. A total of 40 Sprague-Dawley female rats (7 weeks) were divided into four groups and bred for 12 weeks: sham-operated group (Sham), ovariectomized group (OVX), ovariectomized with inorganic calcium and magnesium supplementation group (OVX-Mg), and ovariectomized with seaweed calcium and magnesium supplementation group (OVX-SCa). All experimental diets contained 0.5% calcium. The magnesium content in the experimental diet was 0.05% of the diet in the Sham and OVX groups and 0.1% of the diet in the OVX-Mg and OVX-SCa groups. In the calcium balance study, the OVX-Mg and OVX-SCa groups were not significantly different in calcium absorption compared to the OVX group. However, the femoral bone mineral density and strength of the OVX-SCa group were higher than those of the OVX-Mg and OVX groups. Seaweed calcium with magnesium supplementation or magnesium supplementation alone did not affect the serum ALP and CTx levels in ovariectomized rats. In summary, consumption of seaweed calcium extract or inorganic calcium carbonate with magnesium oxide demonstrated the same degree of intestinal calcium absorption, but only the consumption of seaweed calcium extract resulted in increased femoral bone mineral density and strength in ovariectomized rats. Our results suggest that seaweed calcium extract is an effective calcium and magnesium source for improving bone health compared to synthetic calcium and magnesium supplementation.

The effect of variable calcium and very low calcium diets on human calcium metabolism. Ph.D. Thesis. Final Report

NASA Technical Reports Server (NTRS)

Chu, J.

1971-01-01

The effects of a very low calcium diet, with variable high and low protein intake, on the dynamics of calcium metabolism and the mechanism of calciuretics, are examined. The experiment, using male subjects, was designed to study the role of intestinal calcium absorption on urinary calcium excretion, and the rate of production of endogeneously secreted calcium in the gastrointestinal tract. The study showed an average of 70% fractional absorption rate during very low calcium intake, and that a decrease in renal tubular reabsorption of calcium is responsible for calciuretic effects of high protein intake. The study also indicates that there is a tendency to develop osteoporosis after long periods of low calcium intake, especially with a concurrent high protein intake.

Is ionized calcium a reliable predictor of hypocalcemia after total thyroidectomy? A before and after study

PubMed Central

TARTAGLIA, F.; GIULIANI, A.; SGUEGLIA, M.; PATRIZI, G.; DI ROCCO, G.; BLASI, S.; RUSSO, G.; TORTORELLI, G.; GIANNOTTI, D.; REDLER, A.

2014-01-01

Summary Wanting to find a way of identifying patients suitable for early discharge after thyroidectomy, we set out to establish whether ionized calcium concentration is a better predictor of post-surgical hypocalcemia than total serum calcium. Data were analyzed to establish whether serum ionized calcium concentrations are correlated with total serum calcium levels and symptomatic hypocalcemia after thyroidectomy. Sixty-two patients undergoing total thyroidectomy at the Department of Surgical Sciences of the “Sapienza” University of Rome, Italy, in 2010. Ionized calcium was measured before (day 0) and after surgery (days 1, 2 and 60) in all the patients. These measurements were compared with preoperative (day 0) and postoperative total serum calcium levels (days 1, 2 and 60). The preoperative ionized calcium levels differed from the ionized calcium levels recorded on days 1 and 2; this pattern was not observed for the total calcium concentrations. Conversely, total calcium on days I and II correlated significantly with the various ionized calcium measurements. The presence of parathyroid glands in the surgical specimen did not seem to affect suitability for discharge. The statistical analysis showed that ionized calcium measurements are more reliable than total calcium measurements in the immediate and long-term follow-up of total thyroidectomy patients. Applying a 95% confidence interval we established reference values for both total serum calcium and ionized calcium, below which all patients develop postoperative symptomatic hypocalcemia. In conclusion, measurement of ionized calcium, as opposed to total calcium, should be strongly recommended in the immediate and long-term follow-up of total thyroidectomy patients. PMID:24690338

Consequences of calcium decline on the embryogenesis and life history of Daphnia magna.

PubMed

Giardini, Jamie-Lee; Yan, Norman D; Heyland, Andreas

2015-07-01

Ambient calcium is declining in thousands of soft-water lake habitats in temperate regions as a consequence of unsustainable forestry practices, decreased atmospheric calcium deposition and acidic deposition. As their exoskeleton is heavily reinforced with calcium, freshwater crustaceans have a high specific calcium requirement relative to other aquatic organisms. Daphnia, in particular, is an ideal crustacean for investigating the consequences of calcium decline because it is an abundant and important member of freshwater zooplankton communities. Although it has been established that adult and juvenile Daphnia have different tolerances to low ambient calcium as a result of their different life stage-specific calcium requirements, the consequences of declining calcium on embryonic development have never been investigated. Here, we describe the distribution of calcium in embryonic stages of D. magna and introduce a novel and easy to use staging scheme. We tested whether calcium can be traced from mothers to their offspring. Finally, we assessed the fitness consequences of maternal provisioning in limiting calcium environments. We found that while embryos require calcium for their development and moulting, they do not equilibrate with environmental calcium levels. Instead, we were able to trace calcium from mothers to their offspring. Furthermore, our data strongly suggest that females are faced with an allocation trade-off between providing calcium to their offspring and using it for growth and moulting. Together, these data provide novel insights into the consequences of calcium decline for freshwater zooplankton. © 2015. Published by The Company of Biologists Ltd.

Genetically encoded calcium indicators for studying long-term calcium dynamics during apoptosis.

PubMed

Garcia, M Iveth; Chen, Jessica J; Boehning, Darren

2017-01-01

Intracellular calcium release is essential for regulating almost all cellular functions. Specific spatio-temporal patterns of cytosolic calcium elevations are critical determinants of cell fate in response to pro-apoptotic cellular stressors. As the apoptotic program can take hours or days, measurement of long-term calcium dynamics are essential for understanding the mechanistic role of calcium in apoptotic cell death. Due to the technical limitations of using calcium-sensitive dyes to measure cytosolic calcium little is known about long-term calcium dynamics in living cells after treatment with apoptosis-inducing drugs. Genetically encoded calcium indicators could potentially overcome some of the limitations of calcium-sensitive dyes. Here, we compared the performance of the genetically encoded calcium indicators GCaMP6s and GCaMP6f with the ratiometric dye Fura-2. GCaMP6s performed as well or better than Fura-2 in detecting agonist-induced calcium transients. We then examined the utility of GCaMP6s for continuously measuring apoptotic calcium release over the course of ten hours after treatment with staurosporine. We found that GCaMP6s was suitable for measuring apoptotic calcium release over long time courses and revealed significant heterogeneity in calcium release dynamics in individual cells challenged with staurosporine. Our results suggest GCaMP6s is an excellent indicator for monitoring long-term changes cytosolic calcium during apoptosis. Copyright © 2017 Elsevier Ltd. All rights reserved.

Calcium Balance in Chronic Kidney Disease.

PubMed

Hill Gallant, Kathleen M; Spiegel, David M

2017-06-01

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.

Short-term treatment with transdermal nicotine affects the function of canine saphenous veins.

PubMed

Clouse, W D; Rud, K S; Hurt, R D; Miller, V M

2000-01-01

Experiments were designed to determine the effects of nicotine treatment on the functions of saphenous veins used for coronary artery bypass grafts in dogs. Dogs received either no treatment or transdermal nicotine for 5 weeks at doses of 11 mg, 22 mg or 44 mg/day. Saphenous veins were removed and suspended for the measurement of isometric force in organ chambers. Endothelium was removed mechanically from some rings. N(G)-mono-methyl-L-arginine (L-NMMA; 10(-4) M) was used to inhibit the production of nitric oxide. Contractions to alpha2-adrenergic stimulation were decreased in veins from dogs treated with a 22-mg/day dose of transdermal nicotine. In addition, endothelium-dependent relaxations to adenosine-diphosphate (10(-8)-10(-4) M) and the calcium ionophore A23,187 (10(-8)-10(-6) M) were decreased in veins from dogs with a 22-mg/day dose and increased in veins from dogs treated with a 44-mg/day dose. These relaxations were inhibited by L-NMMA. Plasma concentrations of oxidized products of nitric oxide were decreased only in dogs treated with 22 mg/day of nicotine. The relaxation of rings without endothelium (direct response on the smooth muscle) to nitric oxide were not altered by nicotine treatment. These results suggest that the short-term treatment of dogs with intermediate (22 mg/day) but not low (11 mg/day) or high (44 mg/day) doses of transdermal nicotine decreases the endothelial function of veins used for coronary artery bypass grafts. Therefore, changes in plasma products of nitric oxide and endothelium-dependent relaxations mediated by nitric oxide are related to the dose of nicotine treatment.

Mineral materials as feasible amendments to stabilize heavy metals in polluted urban soils.

PubMed

Zhang, Mingkui; Pu, Jincheng

2011-01-01

Four minerals, agricultural limestone (AL), rock phosphate (RP), palygorskite (PG), and calcium magnesium phosphate (CMP), were evaluated by means of chemical fractions of heavy metals in soils and concentrations of heavy metals in leachates from columns to determine their ability to stabilize heavy metals in polluted urban soils. Two urban soils (calcareous soil and acidic soil) polluted with cadmium, copper, zinc and lead were selected and amended in the laboratory with the mineral materials) for 12 months. Results indicated that application of the mineral materials reduced exchangeable metals in the sequence of Pb, Cd > Cu > Zn. The reduction of exchangeable fraction of heavy metals in the soils amended with different mineral materials followed the sequence of CMP, PG > AL > RP. Reductions of heavy metals leached were based on comparison with cumulative totals of heavy metals eluted through 12 pore volumes from an untreated soil. The reductions of the metals eluted from the calcareous soil amended with the RP, AL, PG and CMP were 1.98%, 38.89%, 64.81% and 75.93% for Cd, 8.51%, 40.42%, 60.64% and 55.32% for Cu, 1.76%, 52.94%, 70.00% and 74.12% for Pb, and 28.42%, 52.74%, 64.38% and 49.66% for Zn. Those from the acidic soil amended with the CMP, PG, AL, and RP were 25.65%, 68.06%, 78.01% and 79.06% for Cd, 26.56%, 49.64%, 43.40% and 34.68% for Cu, 44.44%, 33.32%, 61.11% and 69.44% for Pb, and 18.46%, 43.77%, 41.98% and 40.68% for Zn. The CMP and PG treatments were superior to the AL and RP for stabilizing heavy metals in the polluted urban soils.

Multiparameter imaging of calcium and abscisic acid and high-resolution quantitative calcium measurements using R-GECO1-mTurquoise in Arabidopsis.

PubMed

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

2017-10-01

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.

A Closer look at calcium absorption and the benefits and risks of dietary versus supplemental calcium.

PubMed

Booth, Anna; Camacho, Pauline

2013-11-01

To perform a thorough search of the literature on calcium research and specifically address the topic of calcium absorption. PubMed and Ovid were the main engines used for primary literature searches; textbooks, review articles, and book chapters are examples of the other sources used for supplemental information. Regarding calcium absorption, it seems apparent that the absorption efficiency of all calcium salts, regardless of solubility, is fairly equivalent and not significantly less than the absorption efficiency of dietary calcium. However, dietary calcium has been shown to have greater impact in bone building than supplemental calcium. This is likely due to improved absorption with meals and the tendency of people to intake smaller amounts more frequently, which is more ideal for the body's method of absorption. In addition, the cardiovascular risks of excessive calcium intake appear to be more closely related to calcium supplements than dietary calcium; this relationship continues to be controversial in the literature. We conclude that further studies are needed for direct comparison of supplemental and dietary calcium to fully establish if one is superior to the other with regard to improving bone density. We also propose further studies on the cardiovascular risk of long-term increased calcium intake and on physician estimates of patients' daily calcium intake to better pinpoint those patients who require calcium supplementation.

Calcium sources for milk production in Holstein cows via changes in dry matter intake, mineral utilization, and mineral source buffering potential.

PubMed

Wohlt, J E; Ritter, D E; Evans, J L

1986-11-01

Three supplemental sources of inorganic calcium (calcite flour, aragonite, albacar), each differing in particle size and rate of reactivity, provided .6 or .9% calcium in corn silage:grain (1:1 dry matter) diets of high producing dairy cows. All cows were fed calcite flour at .6% calcium during the first 4 wk of lactation. On d 29 of lactation 5 cows were assigned to each of the six diets. Peak milk yield paralleled dry matter intake and was higher when calcite flour and aragonite provided .9% calcium, intermediate when all sources provided .6% calcium, and lower when albacar provided .9% calcium. However, adaptations to calcium source and to particle sizes of a calcium source (.35 to 1190 mu) were made within 40 d by lactating Holsteins. Starch increased and pH decreased in feces of cows fed albacar. Increasing calcium in the diet provided more buffering capacity in the gastrointestinal tract. True absorption of calcium did not differ from linearity due to source when fecal calcium was regressed on ingested calcium but did vary as a function of diet percentage. Thus, calcium retention was increased when cows were fed .9 vs. .6% calcium. These data suggest that a slow reacting (coarser) inorganic calcium source should be fed at a higher amount to optimize feed intake and milk production.

The salutary effect of dietary calcium on bone mass in a rat model of simulated weightlessness

NASA Technical Reports Server (NTRS)

Bikle, D. D.; Globus, R.; Halloran, B. P.; Morey-Holton, E.

1985-01-01

Whether supplementation of dietary calcium reduces the differences in bone mass of unweighed limbs and normally weighted limbs, and whether parathyroid hormone (PTH) and 1,25-dihydroxyvitamin D (1,25(OH)2D) respond differently to dietary calcium in unweighted animals in comparison with pair-fed controls was studied. The hind limbs of rats were unweighted by a tail suspension method and diets containing 0.1% to 2.4% calcium. After 2 weeks serum calcium, phosphorus, PTH and 1,25(OH)2D intestinal calcium transport were determined and bone mass, ash weight, and calcium in the tibia, L-1 vertebra, and humerus were measured. No significant differences in body weights were observed among the various groups. Suspended rats maintained constant levels of serum calcium and phosphate over the wide range of dietary calcium. Serum PTH and 1,25(OH)2D and intestinal calcium transport fell as dietary calcium was increased. Bone calcium in the tibia and vertebra from suspended rats remained less than that from pair-fed control. It is suggested that although no striking difference between suspended and control animals was observed in response to dieteary calcium, increasing dietary calcium may reduce the negative impact of unloading on the calcium content of the unweighted bones. The salutary effect of high dietary calcium appears to be due to inhibition of bone resorption rather than to stimulation of bone formation.

Calcium metabolism and cardiovascular function after spaceflight

NASA Technical Reports Server (NTRS)

Hatton, Daniel C.; Yue, Qi; Dierickx, Jacqueline; Roullet, Chantal; Otsuka, Keiichi; Watanabe, Mitsuaki; Coste, Sarah; Roullet, Jean Baptiste; Phanouvang, Thongchan; Orwoll, Eric;

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

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

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

Extracellular Calcium Has Multiple Targets to Control Cell Proliferation.

PubMed

Capiod, Thierry

2016-01-01

Calcium channels and the two G-protein coupled receptors sensing extracellular calcium, calcium-sensing receptor (CaSR) and GPRC6a, are the two main means by which extracellular calcium can signal to cells and regulate many cellular processes including cell proliferation, migration and invasion of tumoral cells. Many intracellular signaling pathways are sensitive to cytosolic calcium rises and conversely intracellular signaling pathways can modulate calcium channel expression and activity. Calcium channels are undoubtedly involved in the former while the CaSR and GPRC6a are most likely to interfere with the latter. As for neurotransmitters, calcium ions use plasma membrane channels and GPCR to trigger cytosolic free calcium concentration rises and intracellular signaling and regulatory pathways activation. Calcium sensing GPCR, CaSR and GPRC6a, allow a supplemental degree of control and as for metabotropic receptors, they not only modulate calcium channel expression but they may also control calcium-dependent K+ channels. The multiplicity of intracellular signaling pathways involved, their sensitivity to local and global intracellular calcium increase and to CaSR and GPRC6a stimulation, the presence of membrane signalplex, all this confers the cells the plasticity they need to convert the effects of extracellular calcium into complex physiological responses and therefore determine their fate.

Discrete-State Stochastic Models of Calcium-Regulated Calcium Influx and Subspace Dynamics Are Not Well-Approximated by ODEs That Neglect Concentration Fluctuations

PubMed Central

Weinberg, Seth H.; Smith, Gregory D.

2012-01-01

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

Calcium regulation in crustaceans during the molt cycle: a review and update.

PubMed

Ahearn, Gregory A; Mandal, Prabir K; Mandal, Anita

2004-02-01

Epithelial cells of the gut, gills, antennal glands and integument regulate calcium concentrations in crustaceans during the molt cycle. A cellular calcium transport model has been proposed suggesting the presence of calcium pumps, cation antiporters and calcium channels in transporting epithelial membranes that regulate the movements of this cation across the cell layer. Basolateral calcium transport during postmolt appears mainly regulated by the low affinity NCX antiporter, while calcium regulating 'housekeeping' activities of these cells in intermolt are controlled by the high affinity calcium ATPase (PMCA). A model is proposed for the involvement of the epithelial ER in the massive transepithelial calcium fluxes that occur during premolt and postmolt. This model involves the endoplasmic reticulum SERCA and RyR proteins and proposed cytoplasmic unstirred layers adjacent to apical and basolateral plasma membranes where calcium activities may largely exceed those in the bulk cytoplasmic phase. A result of the proposed transepithelial calcium transport model is that large quantities of calcium can be moved through these cells by these processes without affecting the low, and carefully controlled, bulk cytoplasmic calcium activities.

PRESENILIN-NULL CELLS HAVE ALTERED TWO-PORE CALCIUM CHANNEL EXPRESSION AND LYSOSOMAL CALCIUM; IMPLICATIONS FOR LYSOSOMAL FUNCTION

PubMed Central

Kayala, Kara M Neely; Dickinson, George D; Minassian, Anet; Walls, Ken C; Green, Kim N; LaFerla, Frank M

2012-01-01

Presenilins are necessary for calcium homeostasis and also for efficient proteolysis through the autophagy/lysosome system. Presenilin regulates both endoplasmic reticulum calcium stores and autophagic proteolysis in a γ-secretase independent fashion. The endo-lysosome system can also act as a calcium store, with calcium efflux channels being recently identified as two-pore channels 1 and 2. Here we investigated lysosomal calcium content and the channels that mediate calcium release from these acidic stores in presenilin knockout cells. We report that presenilin loss leads to a lower total lysosomal calcium store despite the buildup of lysosomes found in these cells. Additionally, we find alterations in two-pore calcium channel protein expression, with loss of presenilin preventing the formation of a high molecular weight species of TPC1 and TPC2. Finally, we find that treatments that disturb lysosomal calcium release lead to a reduction in autophagy function yet lysosomal inhibitors do not alter two-pore calcium channel expression. These data indicate that alterations in lysosomal calcium in the absence of presenilins might be leading to disruptions in autophagy. PMID:23103503

Dietary calcium requirements do not differ between Mexican-American boys and girls.

PubMed

Palacios, Cristina; Martin, Berdine R; McCabe, George P; McCabe, Linda; Peacock, Munro; Weaver, Connie M

2014-08-01

Mexican Americans are an understudied ethnic group for determinants of bone health, although the risk of age-related osteoporosis is high in this rapidly growing sector of the U.S. population. Thus, the objective of the present study was to establish the dietary calcium requirements for bone health in Mexican-American adolescents by measuring calcium retention calculated from balance in response to a range of dietary calcium intakes and to determine predictors of skeletal calcium retention. Adolescents aged 12-15 y were studied twice on paired calcium intakes ranging from 600 to 2300 mg/d using randomized-order, crossover 3-wk balance studies. Skeletal calcium retention was calculated as dietary calcium intake minus calcium excreted in feces and urine over the last 2 wk of balance. A linear model was developed to explain the variation in calcium retention. Boys (n = 20) were taller and had higher lean mass, usual dietary calcium intake, bone mineral content, and serum alkaline phosphatase compared with girls, whereas girls (n = 20) had higher Tanner scores and greater fat mass. Calcium retention increased with calcium intake (P < 0.0001) and did not differ by sex (P = 0.66). In boys and girls considered together, calcium intake explained 33% of the variation in calcium retention. Serum alkaline phosphatase explained an additional 11% of the variation in calcium retention. Other variables measured, including the urine N-telopeptide of type I collagen/creatinine ratio, Tanner score, serum parathyroid hormone and 25-hydroxyvitamin D, weight, height, and body mass index, did not contribute to the variance in calcium retention. In adolescence, calcium retention in both Mexican-American boys and girls was higher than determined previously in adolescent nonHispanic white girls. This trial was registered at clinicaltrials.gov as NCT01277185. © 2014 American Society for Nutrition.

Prolonged exposure to 1,25(OH)2D3 and high ionized calcium induces FGF-23 production in intestinal epithelium-like Caco-2 monolayer: A local negative feedback for preventing excessive calcium transport.

PubMed

Rodrat, Mayuree; Wongdee, Kannikar; Panupinthu, Nattapon; Thongbunchoo, Jirawan; Teerapornpuntakit, Jarinthorn; Krishnamra, Nateetip; Charoenphandhu, Narattaphol

2018-02-15

Overdose of oral calcium supplement and excessive intestinal calcium absorption can contribute pathophysiological conditions, e.g., nephrolithiasis, vascular calcification, dementia, and cardiovascular accident. Since our previous investigation has indicated that fibroblast growth factor (FGF)-23 could abolish the 1,25-dihydroxyvitamin D 3 [1,25(OH) 2 D 3 ]-enhanced calcium absorption, we further hypothesized that FGF-23 produced locally in the enterocytes might be part of a local negative feedback loop to regulate calcium absorption. Herein, 1,25(OH) 2 D 3 was found to enhance the transcellular calcium transport across the epithelium-like Caco-2 monolayer, and this stimulatory effect was diminished by preceding prolonged exposure to high-dose 1,25(OH) 2 D 3 or high concentration of apical ionized calcium. Pretreatment with a neutralizing antibody for FGF-23 prevented this negative feedback regulation of calcium hyperabsorption induced by 1,25(OH) 2 D 3 . FGF-23 exposure completely abolished the 1,25(OH) 2 D 3 -enhanced calcium transport. Western blot analysis revealed that FGF-23 expression was upregulated in a dose-dependent manner by 1,25(OH) 2 D 3 or apical calcium exposure. Finally, calcium-sensing receptor (CaSR) inhibitors were found to prevent the apical calcium-induced suppression of calcium transport. In conclusion, prolonged exposure to high apical calcium and calcium hyperabsorption were sensed by CaSR, which, in turn, increased FGF-23 expression to suppress calcium transport. This local negative feedback loop can help prevent unnecessary calcium uptake and its detrimental consequences. Copyright © 2018 Elsevier Inc. All rights reserved.

The Association Between Calcium, Magnesium, and Ratio of Calcium/Magnesium in Seminal Plasma and Sperm Quality.

PubMed

Liang, Hong; Miao, Maohua; Chen, Jianping; Chen, Kanglian; Wu, Bin; Dai, Qi; Wang, Jian; Sun, Fei; Shi, Huijuan; Yuan, Wei

2016-11-01

The study aimed to examine the relationships between calcium, magnesium, and calcium/magnesium ratio in semen plasma and sperm quality. It was a cross-sectional study based on a program aiming at promoting the reproductive health in less-developed areas. A total of 515 men aged between 18 and 55 years provided semen specimens at family planning clinics in Sandu County, Guizhou Province, China. Total calcium and magnesium concentrations in semen plasma were measured with flame atomic absorption spectrometry. Sperm quality, including sperm motility and concentration, was evaluated by using a computer-assisted sperm analysis method. The medians of seminal plasma calcium, magnesium, and zinc concentrations were 9.61, 4.41, and 2.23 mmol/l, respectively. Calcium concentration and calcium/magnesium ratio were negatively associated with sperm concentrations (β = -0.47, P = 0.0123 for calcium; β = -0.25, P = 0.0393 for calcium/magnesium ratio) after adjusting for zinc and other covariates. In stratified analyses, the association between calcium and sperm concentrations only persisted among subjects with a calcium/magnesium ratio of ≤2.5 (β = -0.71, P = 0.0268). In the same stratum, magnesium was associated with increased sperm concentration (β = 0.73, P = 0.0386). Among subjects with a calcium/magnesium ratio of >2.5, neither calcium nor magnesium was associated with sperm concentration. In conclusion, total calcium and magnesium concentrations were associated with sperm concentration among subjects with a lower calcium/magnesium ratio. The calcium and magnesium ratio had a modifying effect on the associations of calcium and magnesium with sperm concentration.

Analysis of Spontaneous and Nerve-Evoked Calcium Transients in Intact Extraocular Muscles in Vitro

PubMed Central

Feng, Cheng-Yuan; Hennig, Grant W.; Corrigan, Robert D.; Smith, Terence K.; von Bartheld, Christopher S.

2012-01-01

Extraocular muscles (EOMs) have unique calcium handling properties, yet little is known about the dynamics of calcium events underlying ultrafast and tonic contractions in myofibers of intact EOMs. Superior oblique EOMs of juvenile chickens were dissected with their nerve attached, maintained in oxygenated Krebs buffer, and loaded with fluo-4. Spontaneous and nerve stimulation-evoked calcium transients were recorded and, following calcium imaging, some EOMs were double-labeled with rhodamine-conjugated alpha-bungarotoxin (rhBTX) to identify EOM myofiber types. EOMs showed two main types of spontaneous calcium transients, one slow type (calcium waves with 1/2max duration of 2–12 s, velocity of 25–50 μm/s) and two fast “flash-like” types (Type 1, 30–90 ms; Type 2, 90–150 ms 1/2max duration). Single pulse nerve stimulation evoked fast calcium transients identical to the fast (Type 1) calcium transients. Calcium waves were accompanied by a local myofiber contraction that followed the calcium transient wavefront. The magnitude of calcium-wave induced myofiber contraction far exceeded those of movement induced by nerve stimulation and associated fast calcium transients. Tetrodotoxin eliminated nerve-evoked transients, but not spontaneous transients. Alpha-bungarotoxin eliminated both spontaneous and nerve-evoked fast calcium transients, but not calcium waves, and caffeine increased wave activity. Calcium waves were observed in myofibers lacking spontaneous or evoked fast transients, suggestive of multiply-innervated myofibers, and this was confirmed by double-labeling with rhBTX. We propose that the abundant spontaneous calcium transients and calcium waves with localized contractions that do not depend on innervation may contribute to intrinsic generation of tonic functions of EOMs. PMID:22579493

Calcium movements and the cellular basis of gravitropism

NASA Astrophysics Data System (ADS)

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.

Effect of Potassium Citrate on Calcium Phosphate Stones in a Model of Hypercalciuria

PubMed Central

Asplin, John R.; Frick, Kevin K.; Granja, Ignacio; Culbertson, Christopher D.; Ng, Adeline; Grynpas, Marc D.; Bushinsky, David A.

2015-01-01

Potassium citrate is prescribed to decrease stone recurrence in patients with calcium nephrolithiasis. Citrate binds intestinal and urine calcium and increases urine pH. Citrate, metabolized to bicarbonate, should decrease calcium excretion by reducing bone resorption and increasing renal calcium reabsorption. However, citrate binding to intestinal calcium may increase absorption and renal excretion of both phosphate and oxalate. Thus, the effect of potassium citrate on urine calcium oxalate and calcium phosphate supersaturation and stone formation is complex and difficult to predict. To study the effects of potassium citrate on urine supersaturation and stone formation, we utilized 95th-generation inbred genetic hypercalciuric stone-forming rats. Rats were fed a fixed amount of a normal calcium (1.2%) diet supplemented with potassium citrate or potassium chloride (each 4 mmol/d) for 18 weeks. Urine was collected at 6, 12, and 18 weeks. At 18 weeks, stone formation was visualized by radiography. Urine citrate, phosphate, oxalate, and pH levels were higher and urine calcium level was lower in rats fed potassium citrate. Furthermore, calcium oxalate and calcium phosphate supersaturation were higher with potassium citrate; however, uric acid supersaturation was lower. Both groups had similar numbers of exclusively calcium phosphate stones. Thus, potassium citrate effectively raises urine citrate levels and lowers urine calcium levels; however, the increases in urine pH, oxalate, and phosphate levels lead to increased calcium oxalate and calcium phosphate supersaturation. Potassium citrate induces complex changes in urine chemistries and resultant supersaturation, which may not be beneficial in preventing calcium phosphate stone formation. PMID:25855777

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

Code of Federal Regulations, 2010 CFR

2010-04-01

... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO 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...

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

Code of Federal Regulations, 2012 CFR

2012-04-01

... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO 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...

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

Code of Federal Regulations, 2013 CFR

2013-04-01

... SERVICES (CONTINUED) FOOD FOR HUMAN CONSUMPTION (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO 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...

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

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

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

Calcium-deficiency assessment and biomarker identification by an integrated urinary metabonomics analysis

PubMed Central

2013-01-01

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 correlation, r = 0.53, P = 0.0001) and citrate (Pearson correlation, r = -0.43, P = 0.001), were further confirmed in 70 women. Conclusions To our knowledge, this is the first report of reliable biomarkers of calcium deficiency, which were identified using an integrated strategy. The identified biomarkers give new insights into the pathophysiological changes and molecular mechanisms of calcium deficiency. The correlations between calcium intake and two of the biomarkers provide a rationale or potential for further assessment and elucidation of the metabolic responses of calcium deficiency in humans. PMID:23537001

Roles of calcium and pH in activation of eggs of the medaka fish, Oryzias latipes

PubMed Central

1983-01-01

Unfertilized eggs of the medaka fish (Oryzias latipes) were injected with pH-buffered calcium buffers. Medaka egg activation is accompanied by a transient increase in cytoplasmic free calcium (Gilkey, J. C., L. F. Jaffe, E. B. Ridgway, and G. T. Reynolds, 1978, J. Cell Biol., 76:448-466). The calcium buffer injections demonstrated that (a) the threshold free calcium required to elicit the calcium transient and activate the egg is between 1.7 and 5.1 microM at pH 7.0, well below the 30 microM reached during the transient, and (b) buffers which hold free calcium below threshold prevent activation of the buffered region in subsequently fertilized eggs. Therefore an increase in free calcium is necessary and sufficient to elicit the calcium transient, and the calcium transient is necessary to activate the egg. Further, these results are additional proof that the calcium transient is initiated and propagated through the cytoplasm by a mechanism of calcium- stimulated calcium release. Finally, a normal calcium transient must propagate through the entire cytoplasm to ensure normal development. Unfertilized eggs were injected with pH buffers to produce short-term, localized changes in cytoplasmic pH. The eggs were then fertilized at various times after injection. In other experiments, unfertilized and fertilized eggs were exposed to media containing either NH4Cl or CO2 to produce longer term, global changes in cytoplasmic pH. These treatments neither activated the eggs nor interfered with the normal development of fertilized eggs, suggesting that even if a natural change in cytoplasmic pH is induced by activation, it has no role in medaka egg development. The injected pH buffers altered the rate of propagation of the calcium transient through the cytoplasm, suggesting that the threshold free calcium required to trigger calcium-stimulated calcium release might be pH dependent. The results of injection of pH-buffered calcium buffers support this conjecture: for a tenfold increase in hydrogen ion concentration, free calcium must also be raised tenfold to elicit the calcium transient. PMID:6411737

Evaluation of calcium ion, hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments: An in vitro study

PubMed Central

Fulzele, Punit; Baliga, Sudhindra; Thosar, Nilima; Pradhan, Debaprya

2011-01-01

Aims: Evaluation of calcium ion and hydroxyl ion release and pH levels in various calcium hydroxide based intracanal medicaments. Objective: The purpose of this study was to evaluate calcium and hydroxyl ion release and pH levels of calcium hydroxide based products, namely, RC Cal, Metapex, calcium hydroxide with distilled water, along with the new gutta-percha points with calcium hydroxide. Materials and Methods: The materials were inserted in polyethylene tubes and immersed in deionized water. The pH variation, Ca++ and OH- release were monitored periodically for 1 week. Statistical Analysis Used: Statistical analysis was carried out using one-way analysis of variance and Tukey's post hoc tests with PASW Statistics version 18 software to compare the statistical difference. Results: After 1 week, calcium hydroxide with distilled water and RC Cal raised the pH to 12.7 and 11.8, respectively, while a small change was observed for Metapex, calcium hydroxide gutta-percha points. The calcium released after 1 week was 15.36 mg/dL from RC Cal, followed by 13.04, 1.296, 3.064 mg/dL from calcium hydroxide with sterile water, Metapex and calcium hydroxide gutta-percha points, respectively. Conclusions: Calcium hydroxide with sterile water and RC Cal pastes liberate significantly more calcium and hydroxyl ions and raise the pH higher than Metapex and calcium hydroxidegutta-percha points. PMID:22346155

Significance of Ca-soap formation for calcium absorption in the rat.

PubMed Central

Gacs, G; Barltrop, D

1977-01-01

The significance of calcium soap formation in the inhibition of calcium absorption has been studied in rats. 47Ca labelled soaps of fatty acids were introduced into the duodenum and the absorption of calcium measured after four hours in a whole body counter. The absorption of calcium was inversely correlated with the chain length of the fatty acid varying from 1% for Ca-stearate to 60% for Ca-hexanoate. Increasing the degree of unsaturation of the fatty acid was accompanied by increased calcium absorption. The availability of calcium for absorption from the soaps was correlated with their solubility in 1% aqueous Na-tauroglycocholate. The percentages of calcium as soap in the small intestine and the faeces after intragastric administration of calcium and fats were similar, which suggests that the faecal content of calcium soaps is an index of intestinal soap formation. Soap formation was negligible when CaCl2 was given with tristearate, triolaeate, or tridecanoate and no depression of calcium absorption was observed. Calcium absorption was markedly impaired by the addition of phosphates at a Ca/P ratio of 1:1 irrespective of the presence of neutral fats. Stearic acid resulted in significant soap formation and reduced calcium absorption. The degree of Ca-soap formation and the inhibition of calcium absorption were well correlated. The results suggest that, although calcium soap formation may markedly depress calcium absorption in the rat, no significant soap formation takes place when fats are given in the form of triglycerides. PMID:838405

Calcium homeostasis in intraerythrocytic malaria parasites.

PubMed

Garcia, C R; Dluzewski, A R; Catalani, L H; Burting, R; Hoyland, J; Mason, W T

1996-12-01

The fluorescent indicator, fura-2, AM, was used to measure free calcium concentrations in the intraerythrocytic malaria parasites of Plasmodium chabaudi and Plasmodium falciparum. In both species the free cytosolic calcium concentration was maintained at low levels (between 40 and 100 nM throughout the maturation process. Digital image analysis of the indicator fluorescence was performed on parasites and evaluated with the aid of a calibration of the calcium response, based on permeabilized parasites, exposed to calcium buffers. This again revealed that free calcium concentrations in the intact parasite are maintained at a predetermined level, regardless of the free calcium in the surrounding milieu. Both species of parasites are thus capable of regulating their internal free calcium levels with high precision, presumably by means of calcium pump ATPases. A small but significant elevation of the cytosolic free calcium concentration by the tumor promoter, thapsigargin, may be taken to reflect the presence of calcium stores in the endoplasmic reticulum in P. falciparum.

Calcium ionization balance and argon/calcium abundance in solar flares

NASA Astrophysics Data System (ADS)

Antonucci, E.; Marocchi, D.; Gabriel, A. H.; Doschek, G. A.

1987-12-01

An earlier analysis of solar flare calcium spectra from XRP and P78-1 aimed at measuring the calcium ionization balance resulted in an ambiguity due to a line blend between the calcium q line and an Ar XVII line. In the present work the calcium line 'r' is included in the analysis in order to resolve this problem. It is shown that the correct calcium ionization balance is that indicated in the earlier paper as corresponding to an argon/calcium abundance ratio of 0.2. The argon/calcium abundance ratio in the group of solar flares studied is shown to be 0.2 + or - 0.2. It is further argued that while the abundance of heavy elements may be enhanced in energetic flare events, this enhancement is less for argon than for calcium, leading to an argon/calcium ratio smaller than that present in the quiet sun.

21 CFR 184.1212 - Calcium pantothenate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Calcium pantothenate. 184.1212 Section 184.1212... Listing of Specific Substances Affirmed as GRAS § 184.1212 Calcium pantothenate. (a) Calcium pantothenate... and the DL-racemic mixture of calcium pantothenate are used in food. Commercial calcium pantothenate...

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

Code of Federal Regulations, 2014 CFR

2014-04-01

... SERVICES (CONTINUED) FOOD ADDITIVES PERMITTED FOR DIRECT ADDITION TO 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 be safely used in foods for special...

Absorption of Levothyroxine When Coadministered with Various Calcium Formulations

PubMed Central

Zamfirescu, Isabelle

2011-01-01

Background Calcium carbonate is a commonly used dietary supplement and has been shown to interfere with levothyroxine absorption. However, calcium citrate, which is also used for supplementation purposes, has not been studied previously and calcium acetate, which is used to treat hyperphosphatemia in renal failure, has been reported to show little or no interference with levothyroxine absorption in a retrospective pharmacoepidemiologic study. We aimed to compare the effect of these three calcium formulations on levothyroxine absorption. Materials and Methods The study was conducted in eight healthy, euthyroid adults. We performed single-dose pharmacokinetic studies in which we measured levothyroxine absorption when given alone or when coadministered with calcium carbonate, calcium citrate, or calcium acetate in doses containing 500 mg elemental calcium. Serum thyroxine was measured at intervals over a 6-hour period after ingestion of the study drugs. Results Coadministration of each of the three calcium preparations significantly reduced levothyroxine absorption by about 20%–25% compared with levothyroxine given alone. Conclusions Contrary to a prior report, our data suggest that calcium acetate interferes with levothyroxine absorption in a manner similar to that seen with calcium carbonate and calcium citrate. Although the effect of calcium is modest compared with some other medications previously studied, hypothyroid patients should be cautioned to take their levothyroxine well-separated from all of these calcium formulations. PMID:21595516

Use of Genetically-encoded Calcium Indicators for Live Cell Calcium Imaging and Localization in Virus-infected Cells

PubMed Central

Perry, Jacob L.; Ramachandran, Nina K.; Utama, Budi; Hyser, Joseph M.

2015-01-01

Calcium signaling is a ubiquitous and versatile process involved in nearly every cellular process, and exploitation of host calcium signals is a common strategy used by viruses to facilitate replication and cause disease. Small molecule fluorescent calcium dyes have been used by many to examine changes in host cell calcium signaling and calcium channel activation during virus infections, but disadvantages of these dyes, including poor loading and poor long-term retention, complicate analysis of calcium imaging in virus-infected cells due to changes in cell physiology and membrane integrity. The recent expansion of genetically-encoded calcium indicators (GECIs), including blue and red-shifted color variants and variants with calcium affinities appropriate for calcium storage organelles like the endoplasmic reticulum (ER), make the use of GECIs an attractive alternative for calcium imaging in the context of virus infections. Here we describe the development and testing of cell lines stably expressing both green cytoplasmic (GCaMP5G and GCaMP6s) and red ER-targeted (RCEPIAer) GECIs. Using three viruses (rotavirus, poliovirus and respiratory syncytial virus) previously shown to disrupt host calcium homeostasis, we show the GECI cell lines can be used to detect simultaneous cytoplasmic and ER calcium signals. Further, we demonstrate the GECI expression has sufficient stability to enable long-term confocal imaging of both cytoplasmic and ER calcium during the course of virus infections. PMID:26344758

Increased calcium absorption from synthetic stable amorphous calcium carbonate: Double-blind randomized crossover clinical trial in post-menopausal women

USDA-ARS?s Scientific Manuscript database

Calcium supplementation is a widely recognized strategy for achieving adequate calcium intake. We designed this blinded, randomized, crossover interventional trial to compare the bioavailability of a new stable synthetic amorphous calcium carbonate (ACC) with that of crystalline calcium carbonate (C...

The Role of Calcium in Prevention and Treatment of Osteoporosis.

ERIC Educational Resources Information Center

Heaney, Robert P.

1987-01-01

Osteoporosis results from several factors. Calcium deficiency is only one, and high calcium intake will prevent only those cases in which calcium is the limiting factor. Calcium cannot reverse, but only arrest, bone loss. A high calcium intake for every member of the population is advocated. (Author/MT)

Calcium kinetics during bed rest with artificial gravity and exercise countermeasures

USDA-ARS?s Scientific Manuscript database

We assessed the potential for countermeasures to lessen the loss of bone calcium during bed rest. Subjects ingested less calcium during bed rest, and with artificial gravity, they also absorbed less calcium. With exercise, they excreted less calcium. To retain bone during bed rest, calcium intake ne...

Masters or slaves? Vesicle release machinery and the regulation of presynaptic calcium channels.

PubMed

Jarvis, Scott E; Zamponi, Gerald W

2005-05-01

Calcium entry through presynaptic voltage-gated calcium channels is essential for neurotransmitter release. The two major types of presynaptic calcium channels contain a synaptic protein interaction site that physically interacts with synaptic vesicle release proteins. This is thought to tighten the coupling between the sources of calcium entry and the neurotransmitter release machinery. Conversely, the binding of synaptic proteins to presynaptic calcium channels regulates calcium channel activity. Hence, presynaptic calcium channels act not only as the masters of the synaptic release process, but also as key targets for feedback inhibition.

The calcium-sensing receptor regulates mammary gland parathyroid hormone–related protein production and calcium transport

PubMed Central

VanHouten, Joshua; Dann, Pamela; McGeoch, Grace; Brown, Edward M.; Krapcho, Karen; Neville, Margaret; Wysolmerski, John J.

2004-01-01

The transfer of calcium from mother to milk during lactation is poorly understood. In this report, we demonstrate that parathyroid hormone–related protein (PTHrP) production and calcium transport in mammary epithelial cells are regulated by extracellular calcium acting through the calcium-sensing receptor (CaR). The CaR becomes expressed on mammary epithelial cells at the transition from pregnancy to lactation. Increasing concentrations of calcium, neomycin, and a calcimimetic compound suppress PTHrP secretion by mammary epithelial cells in vitro, whereas in vivo, systemic hypocalcemia increases PTHrP production, an effect that can be prevented by treatment with a calcimimetic. Hypocalcemia also reduces overall milk production and calcium content, while increasing milk osmolality and protein concentrations. The changes in milk calcium content, milk osmolality, and milk protein concentration were mitigated by calcimimetic infusions. Finally, in a three-dimensional culture system that recapitulates the lactating alveolus, activation of the basolateral CaR increases transcellular calcium transport independent of its effect on PTHrP. We conclude that the lactating mammary gland can sense calcium and adjusts its secretion of calcium, PTHrP, and perhaps water in response to changes in extracellular calcium concentration. We believe this defines a homeostatic system that helps to match milk production to the availability of calcium. PMID:14966569

Effects of Eggshell Calcium Supplementation on Bone Mass in Postmenopausal Vietnamese Women.

PubMed

Sakai, Seigo; Hien, Vu Thi Thu; Tuyen, Le Danh; Duc, Ha Anh; Masuda, Yasunobu; Yamamoto, Shigeru

2017-01-01

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 (p<0.05) and was significantly higher than that of the placebo and calcium carbonate groups at 12 mo (p<0.05). The SOS of the calcium carbonate group tended to be higher than that of the placebo group but without a significant difference (p>0.05). In conclusion, eggshell calcium was more effective in increasing bone mass than calcium carbonate in postmenopausal Vietnamese women.

Calcium deprivation increases the palatability of calcium solutions in rats.

PubMed

McCaughey, Stuart A; Forestell, Catherine A; Tordoff, Michael G

2005-02-15

Calcium-deprived rats have elevated intakes of CaCl2, other calcium salts, and some non-calcium compounds. We used taste reactivity to examine the effects of calcium deprivation on the palatability of CaCl2 and other solutions. Nine male Sprague-Dawley rats were calcium-deprived by maintenance on a low-calcium diet, and eight replete rats were used as controls. All rats were videotaped during intraoral infusion of the following solutions: 30 and 300 mM CaCl2, 30 mM calcium lactate, 100 and 600 mM NaCl, 30 mM MgCl2, 1 mM quinine.HCl, 2.5 mM sodium saccharin, and deionized water. We counted individual orofacial and somatic movements elicited by the infusions and used them to calculate total ingestive and aversive scores. Relative to controls, calcium-deprived rats gave a significantly larger number of tongue protrusions and had higher total ingestive scores for CaCl2, calcium lactate, NaCl, and MgCl2. Our results suggest that CaCl2, calcium lactate, NaCl, and MgCl2 taste more palatable to rats when they are calcium-deprived than replete, and this may be responsible for the increased intake of these solutions following calcium deprivation.

Vitamin D Status and Calcium Metabolism in Adolescent Black and White Girls on a Range of Controlled Calcium Intakes

PubMed Central

Weaver, Connie M.; McCabe, Linda D.; McCabe, George P.; Braun, Michelle; Martin, Berdine R.; DiMeglio, Linda A.; Peacock, Munro

2008-01-01

Background: There are limited data in adolescents on racial differences in relationships between dietary calcium intake, absorption, and retention and serum levels of calcium-regulating hormones. Objectives: The aim of this study was to investigate these relationships cross-sectionally in American White and Black adolescent girls. Methods: Calcium balance studies were conducted in 105 girls, aged 11–15 yr, on daily calcium intakes ranging from 760–2195 mg for 3-wk controlled feeding periods; 158 observations from 52 Black and 53 White girls were analyzed. Results: Black girls had lower serum 25-hydroxyvitamin D [25(OH)D], higher serum 1,25-dihydroxyvitamin D, and higher calcium absorption and retention than White girls. Calcium intake and race, but not serum 25(OH)D, predicted net calcium absorption and retention with Black girls absorbing calcium more efficiently at low calcium intakes than White girls. The relationship between serum 25(OH)D and serum PTH was negative only in White girls. Calcium intake, race, and postmenarcheal age explained 21% of the variation in calcium retention, and serum 25(OH)D did not contribute further to the variance. Conclusions: These results suggest that serum 25(OH)D does not contribute to the racial differences in calcium absorption and retention during puberty. PMID:18682505

[Effects of fertilizing regime and planting age on soil calcium decline in Luochuan apple orchards].

PubMed

Li, Peng; Li, Chun Yue; Wang, Yi Quan; Jiao, Cai Qiang

2017-05-18

This study was conducted to assess the effects of fertilizing regime and orchard planting age on soil calcium contents and stocks in the apple orchards on the Loess Plateau. The apple orchards in Luochuan County, one of the best regions for apple plantation in the world, were selec-ted in this study. The contents of calcium carbonate,water-soluble calcium and exchangeable cal-cium at 0-100 cm soil layer under different fertilizing regimes and various planting ages were mea-sured, their stocks were calculated and their variation features were analyzed. The results showed that soil in the apple orchards in the study region was characterized by the decline in calcium contents. The decline was more serious in apple orchards with long-term application of chemical fertili-zer than in those with combined application of chemical fertilizer and farmyard manure. The average contents of calcium carbonate, water-soluble calcium and exchangeable calcium at 0-100 cm soil layer in apple orchards with long-term application of chemical fertilizer decreased by 38.8%, 25.4% and 5.6% respectively than those in the apple orchards with long-term application of both chemical fertilizer and farmyard manure. The stocks of calcium carbonate, water-soluble calcium and exchangeable calcium decreased by 36.4%, 26.0% and 4.3%, respectively. The decline of soil cal-cium was aggravated with the increase of orchard planting age. The contents of calcium carbonate, water-soluble calcium and exchangeable calcium at 0-100 cm soil layer in orchards of more than 25 years of planting age decreased by 48.8%, 69.4% and 39.5% respectively, compared with orchards of less than 10 years of planting age, and the stocks decreased by 40.8%, 64.1% and 33.0%, respectively. These results indicated that either long-term application of chemical fertilizer or long-term plantation of apple trees obviously depleted soil calcium carbonate, water-soluble calcium and exchangeable calcium. Therefore, it was recommended that application of chemical fertilizer and farmyard manure should be combined to mitigate soil calcium decline, and calcium management should be strengthened in apple orchards of more than 25 years of planting age. The fertilizing regime was a driving factor of soil calcium decline which had a significant temporal (orchard planting age) and spatial (soil depth) effect.

Dietary calcium deficiency in laying ducks impairs eggshell quality by suppressing shell biomineralization.

PubMed

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

2015-10-01

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 (P<0.05) during the depletion period, accompanied by reduced tibia quality. The mRNA expression of both secreted phosphoprotein 1 (SPP1) and carbonic anhydrase 2 (CA2) in the uterus was decreased after feeding calcium-deficient diets (1.8% or 0.38% calcium). mRNA transcripts of calbindin 1 (CALB1), an important protein responsible for calcium transport, and the matrix protein genes ovocalyxin-32 (OCX-32) and ovocleidin-116 (OC-116) were reduced in ducks fed 0.38% calcium but not 1.8% calcium. Plasma estradiol concentration was decreased by both of the calcium-deficient diets (P<0.05). The impaired shell quality and suppressed functional proteins involved in shell formation could be reversed by repletion of dietary calcium. The results of the present study suggest that dietary calcium deficiency negatively affects eggshell quality and microarchitecture, probably by suppressing shell biomineralization. © 2015. Published by The Company of Biologists Ltd.

Calcium bioavailability and kinetics of calcium ascorbate and calcium acetate in rats.

PubMed

Cai, Jianwei; Zhang, Qinmin; Wastney, Meryl E; Weaver, Connie M

2004-01-01

The objective was to investigate the bioavailability and mechanism of calcium absorption of calcium ascorbate (ASC) and calcium acetate (AC). A series of studies was performed in adult Sprague-Dawley male rats. In the first study, each group of rats (n = 10/group) was assigned to one of the five test meals labeled with (45)Ca: (i) 25 mg calcium as heated ASC or (ii) unheated ASC, (iii) 25 mg calcium as unheated AC, (iv) 3.6 mg Ca as unheated ASC, or (v) unheated AC. Femur uptake indicated better calcium bioavailability from ASC than AC at both calcium loads. A 5-min heat treatment partly reduced bioavailability of ASC. Kinetic studies were performed to further investigate the mechanism of superior calcium bioavailability from ASC. Two groups of rats (n = 10/group) received oral doses of 25 mg Ca as ASC or AC. Each dose contained 20 micro Ci (45)Ca. Two additional groups of rats (n = 10/group) received an intravenous injection (iv) of 10 micro Ci (45)Ca after receiving an unlabeled oral dose of 25 mg calcium as ASC or AC. Sequential blood samples were collected over 48 hrs. Urine and fecal samples were collected every 12 hrs for 48 hrs and were analyzed for total calcium and (45)Ca content. Total calcium and (45)Ca from serum, urine, and feces were fitted by a compartment kinetics model with saturable and nonsaturable absorption pathways by WinSAAM (Windows-based Simulation Analysis and Modeling). The difference in calcium bioavailability between the two salts was due to differences in saturable rather than passive intestinal absorption and not to endogenous secretion or calcium deposition rate. The higher bioavailability of calcium ascorbate was due to a longer transit time in the small intestine compared with ASC.

Calcium Intake in Elderly Australian Women Is Inadequate

PubMed Central

Meng, Xingqiong; Kerr, Deborah A.; Zhu, Kun; Devine, Amanda; Solah, Vicky; Binns, Colin W.; Prince, Richard L.

2010-01-01

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. PMID:22254072

Effects of nicergoline on calcium and magnesium deposition in the central nervous system tissues of rats maintained on low-calcium diets.

PubMed

Yasui, M; Kihira, T; Tsujimoto, M; Ota, K

1992-11-01

Reduction of calcium intake leads to the mobilization of calcium and magnesium from the bone pool and to calcium deposition in the soft tissues, especially in the central nervous system (CNS). The effects of 10 alpha-methoxy-1,6-dimethylergoline-8 beta-methanol 5-bromonicotinate (nicergoline), an ameliorator of cerebral circulation and metabolism, on the deposition of calcium and magnesium in the CNS, heart, liver, kidney, muscle, abdominal aorta and bones were studied in rats maintained on standard and low-calcium diets. Rats were fed the following diets for 90 days: standard calcium (12.5 g/kg); standard calcium with 60 mg/kg nicergoline; low-calcium (30 mg/kg); and low-calcium with 60 mg/kg nicergoline. The presence of nicergoline did not affect blood chemistry but magnesium concentrations in the liver were significantly (P < 0.05) higher in rats fed standard diet with nicergoline. Magnesium concentrations in the occipital cortex, pons, cerebellum, liver, kidney, muscle and femur of nicergoline-treated rats fed low-calcium diet were significantly (P < 0.01-0.05) higher compared with those in the corresponding controls, whereas the calcium concentrations in the femur of nicergoline-treated rats fed both standard and low-calcium diets were significantly (P < 0.05) higher than those in the corresponding controls. In general, nicergoline tended to preserve the calcium content in the bone of rats fed a standard diet. Nicergoline may be implicated in calcium metabolism in rats fed low-calcium diets and may activate cerebral metabolism through the maintenance of magnesium concentrations in the CNS and soft tissues.

TMEM203 Is a Novel Regulator of Intracellular Calcium Homeostasis and Is Required for Spermatogenesis

PubMed Central

Shambharkar, Prashant B.; Bittinger, Mark; Latario, Brian; Xiong, ZhaoHui; Bandyopadhyay, Somnath; Davis, Vanessa; Lin, Victor; Yang, Yi; Valdez, Reginald; Labow, Mark A.

2015-01-01

Intracellular calcium signaling is critical for initiating and sustaining diverse cellular functions including transcription, synaptic signaling, muscle contraction, apoptosis and fertilization. Trans-membrane 203 (TMEM203) was identified here in cDNA overexpression screens for proteins capable of modulating intracellular calcium levels using activation of a calcium/calcineurin regulated transcription factor as an indicator. Overexpression of TMEM203 resulted in a reduction of Endoplasmic Reticulum (ER) calcium stores and elevation in basal cytoplasmic calcium levels. TMEM203 protein was localized to the ER and found associated with a number of ER proteins which regulate ER calcium entry and efflux. Mouse Embryonic Fibroblasts (MEFs) derived from Tmem203 deficient mice had reduced ER calcium stores and altered calcium homeostasis. Tmem203 deficient mice were viable though male knockout mice were infertile and exhibited a severe block in spermiogenesis and spermiation. Expression profiling studies showed significant alternations in expression of calcium channels and pumps in testes and concurrently Tmem203 deficient spermatocytes demonstrated significantly altered calcium handling. Thus Tmem203 is an evolutionarily conserved regulator of cellular calcium homeostasis, is required for spermatogenesis and provides a causal link between intracellular calcium regulation and spermiogenesis. PMID:25996873

Analytical solution of reaction-diffusion equations for calcium wave propagation in a starburst amacrine cell.

PubMed

Poznanski, R R

2010-09-01

A reaction-diffusion model is presented to encapsulate calcium-induced calcium release (CICR) as a potential mechanism for somatofugal bias of dendritic calcium movement in starburst amacrine cells. Calcium dynamics involves a simple calcium extrusion (pump) and a buffering mechanism of calcium binding proteins homogeneously distributed over the plasma membrane of the endoplasmic reticulum within starburst amacrine cells. The system of reaction-diffusion equations in the excess buffer (or low calcium concentration) approximation are reformulated as a nonlinear Volterra integral equation which is solved analytically via a regular perturbation series expansion in response to calcium feedback from a continuously and uniformly distributed calcium sources. Calculation of luminal calcium diffusion in the absence of buffering enables a wave to travel at distances of 120 μm from the soma to distal tips of a starburst amacrine cell dendrite in 100 msec, yet in the presence of discretely distributed calcium-binding proteins it is unknown whether the propagating calcium wave-front in the somatofugal direction is further impeded by endogenous buffers. If so, this would indicate CICR to be an unlikely mechanism of retinal direction selectivity in starburst amacrine cells.

Weight loss, ion release and initial mechanical properties of a binary calcium phosphate glass fibre/PCL composite.

PubMed

Ahmed, I; Parsons, A J; Palmer, G; Knowles, J C; Walker, G S; Rudd, C D

2008-09-01

Composites comprising a biodegradable polymeric matrix and a bioactive filler show considerable promise in the field of regenerative medicine, and could potentially serve as degradable bone fracture fixation devices, depending on the properties obtained. Therefore, glass fibres from a binary calcium phosphate (50P(2)O(5)+50CaO) glass were used to reinforce polycaprolactone, at two different volume fractions (V(f)). As-drawn, non-treated and heat-treated fibres were assessed. Weight loss, ion release and the initial mechanical properties of the fibres and composites produced have been investigated. Single fibre tensile testing revealed a fibre strength of 474MPa and a tensile modulus of 44GPa. Weibull analysis suggested a scale value of 524. The composites yielded flexural strength and modulus of up to 30MPa and 2.5GPa, respectively. These values are comparable with human trabecular bone. An 8% mass loss was seen for the lower V(f) composite, whereas for the two higher V(f) composites an approximate 20% mass loss was observed over the course of the 5week study. A plateau in the degradation profile at 350h indicated that fibre dissolution was complete at this interval. This assertion was further supported via ion release studies. The leaching of fibres from the composite created a porous structure, including continuous channels within the polymer matrix. This offers further scope for tailoring scaffold development, as cells from the surrounding tissue may be induced to migrate into the resulting porous matrix.

Inositol phosphates influence the membrane bound Ca/sup 2 +//Mg/sup 2 +/ stimulated ATPase from human erythrocyte membranes

DOE Office of Scientific and Technical Information (OSTI.GOV)

Kester, M.; Ekholm, J.; Kumar, R.

1986-03-01

The modulation by exogenous inositol phosphates of the membrane Ca/sup 2 +//Mg/sup 2 +/ ATPase from saponin/EGTA lysed human erythrocytes was determined in a buffer (pH 7.6) containing histidine, 80 mM, MgCl/sub 2/, 3.3 mM, NaCl, 74 mM, KCl, 30 mM, Na/sub 2/ATP, 2.3 mM, ouabain, 0.83 mM, with variable amounts of CaCl/sub 2/ and EGTA. The ATPase assay was linear with time at 44/sup 0/C. The inositol phosphates were commercially obtained and were also prepared from /sup 32/P labeled rabbit platelet inositol phospholipids. Inositol triphosphate (IP/sub 3/) elevated the Ca/sup 2 +//Mg/sup 2 +/ ATPase activity over basal levelsmore » in a dose, time, and calcium dependent manner and were increased up to 85% of control values. Activities for the Na/sup +//K/sup +/-ATPase and a Mg/sup 2 +/ ATPase were not effected by IP/sub 3/. Ca/sup 2 +//Mg/sup 2 +/APTase activity with IP/sub 2/ or IP/sub 3/ could be synergistically elevated with calmodulin addition. The activation of the ATPase with IP/sub 3/ was calcium dependent in a range from .001 to .02 mM. The apparent Km and Vmax values were determined for IP/sub 3/ stimulated Ca/sup 2 +//Mg/sup 2 +/ ATPase.« less

Cardiovascular risk factors among patients with chronic kidney disease attending a tertiary hospital in Uganda.

PubMed

Babua, Christopher; Kalyesubula, Robert; Okello, Emmy; Kakande, Barbara; Sebatta, Elias; Mungoma, Michael; Mondo, Charles Kiiza

2015-01-01

Chronic kidney disease (CKD) is a risk factor for the development of cardiovascular disease, which is the primary cause of morbidity and mortality in patients with CKD. Local data about cardiovascular risk factors among CKD patients is generally scanty. To determine the prevalence of the common cardiovascular risk factors among patients with CKD attending the nephrology out-patient clinic in Mulago national referral hospital in Uganda. This was a cross-sectional study in which 217 patients with a mean age of 43 years were recruited over a period of nine months. Data on demographic characteristics, risk factors for cardiovascular disease, complete blood count, renal function tests/electrolytes, and lipid profiles were collected using a standardised questionnaire. One hundred and eleven (51.2%) of the participants were male. Hypertension was reported in 90% of participants while cigarette smoking was present in 11.5%. Twenty-two participants (10.2%) were obese and 16.1% were diabetic. A total of 71.9% had a haemoglobin concentration < 11 g/dl, with the prevalence of anaemia increasing with advancing renal failure (p < 0.001); 44.7% were hypocalcaemic and 39.2% had hyperphosphataemia. The prevalence of abnormal calcium and phosphate levels was found to increase with declining renal function (p = 0.004 for calcium and p < 0.001 for phosphate). This study demonstrated that both traditional and non-traditional cardiovascular risk factors occurred frequently in patients with CKD attending the nephrology out-patient clinic at Mulago Hospital.

Development and optimization of a self-microemulsifying drug delivery system for atorvastatin calcium by using D-optimal mixture design.

PubMed

Yeom, Dong Woo; Song, Ye Seul; Kim, Sung Rae; Lee, Sang Gon; Kang, Min Hyung; Lee, Sangkil; Choi, Young Wook

2015-01-01

In this study, we developed and optimized a self-microemulsifying drug delivery system (SMEDDS) formulation for improving the dissolution and oral absorption of atorvastatin calcium (ATV), a poorly water-soluble drug. Solubility and emulsification tests were performed to select a suitable combination of oil, surfactant, and cosurfactant. A D-optimal mixture design was used to optimize the concentration of components used in the SMEDDS formulation for achieving excellent physicochemical characteristics, such as small droplet size and high dissolution. The optimized ATV-loaded SMEDDS formulation containing 7.16% Capmul MCM (oil), 48.25% Tween 20 (surfactant), and 44.59% Tetraglycol (cosurfactant) significantly enhanced the dissolution rate of ATV in different types of medium, including simulated intestinal fluid, simulated gastric fluid, and distilled water, compared with ATV suspension. Good agreement was observed between predicted and experimental values for mean droplet size and percentage of the drug released in 15 minutes. Further, pharmacokinetic studies in rats showed that the optimized SMEDDS formulation considerably enhanced the oral absorption of ATV, with 3.4-fold and 4.3-fold increases in the area under the concentration-time curve and time taken to reach peak plasma concentration, respectively, when compared with the ATV suspension. Thus, we successfully developed an optimized ATV-loaded SMEDDS formulation by using the D-optimal mixture design, that could potentially be used for improving the oral absorption of poorly water-soluble drugs.

Development and optimization of a self-microemulsifying drug delivery system for ator vastatin calcium by using d-optimal mixture design

PubMed Central

Yeom, Dong Woo; Song, Ye Seul; Kim, Sung Rae; Lee, Sang Gon; Kang, Min Hyung; Lee, Sangkil; Choi, Young Wook

2015-01-01

In this study, we developed and optimized a self-microemulsifying drug delivery system (SMEDDS) formulation for improving the dissolution and oral absorption of atorvastatin calcium (ATV), a poorly water-soluble drug. Solubility and emulsification tests were performed to select a suitable combination of oil, surfactant, and cosurfactant. A d-optimal mixture design was used to optimize the concentration of components used in the SMEDDS formulation for achieving excellent physicochemical characteristics, such as small droplet size and high dissolution. The optimized ATV-loaded SMEDDS formulation containing 7.16% Capmul MCM (oil), 48.25% Tween 20 (surfactant), and 44.59% Tetraglycol (cosurfactant) significantly enhanced the dissolution rate of ATV in different types of medium, including simulated intestinal fluid, simulated gastric fluid, and distilled water, compared with ATV suspension. Good agreement was observed between predicted and experimental values for mean droplet size and percentage of the drug released in 15 minutes. Further, pharmacokinetic studies in rats showed that the optimized SMEDDS formulation considerably enhanced the oral absorption of ATV, with 3.4-fold and 4.3-fold increases in the area under the concentration-time curve and time taken to reach peak plasma concentration, respectively, when compared with the ATV suspension. Thus, we successfully developed an optimized ATV-loaded SMEDDS formulation by using the d-optimal mixture design, that could potentially be used for improving the oral absorption of poorly water-soluble drugs. PMID:26089663

Calcium intake in the United States from dietary and supplemental sources across adult age groups: new estimates from the National Health and Nutrition Examination Survey 2003-2006.

PubMed

Mangano, Kelsey M; Walsh, Stephen J; Insogna, Karl L; Kenny, Anne M; Kerstetter, Jane E

2011-05-01

Adequate lifelong calcium intake is essential in optimizing bone health. Recent National Health and Nutrition Examination Survey data were used to quantify variation in calcium intake across adult age groups and to relate age-associated changes in calcium intake with energy intake. Additional goals were to assess differences in dietary calcium intake between supplemental calcium users and nonusers and to evaluate associations between age and calcium density in the diet. This cross-sectional analysis determined calcium and energy intake for National Health and Nutrition Examination Survey respondents during 2003-2006. Diet was assessed with 24-hour recall and supplement use via questionnaire. Trends in median intakes for dietary calcium, total calcium, and energy across age categories were assessed using survey analysis methods. Nutrient density was represented using calcium to energy intake ratios. The analyses included data from 9,475 adults. When compared to the 19- to 30-year age group, median dietary calcium intake was lower in the ≥81-year age group by 23% in men (P<0.001) and by 14% in women (P=0.003). These reductions coincided with 35% and 28% decreases, respectively, in median energy intake (P<0.001 for each sex). In contrast, the frequency of calcium supplement use increased (P<0.001) with age in both men and women. Yet, among female supplement users, the decline in median dietary calcium intake was greater than in nonusers (P=0.02). Calcium density in the diet significantly increased relative to age in men and women (P<0.001 for each sex); however, dietary and total calcium to energy ratios were insufficient to meet target ratios inferred by adequate intake standards after age 50 years. Although supplemental calcium use and calcium density were highest in older age groups, they were not sufficient in meeting recommended levels. New approaches to increasing the frequency and level of calcium supplement use to enhance calcium density in diets may be necessary to reduce osteoporosis risk among older Americans. Copyright © 2011 American Dietetic Association. Published by Elsevier Inc. All rights reserved.

A possible molecular mechanism of the action of digitalis: ouabain action on calcium binding to sites associated with a purified sodium-potassium-activated adenosine triphosphatase from kidney.

PubMed

Gervais, A; Lane, L K; Anner, B M; Lindenmayer, G E; Schwartz, A

1977-01-01

Calcium binding at 0 degrees C to a purified sheep kidney Na+,K+-ATPase was described by linear Scatchard plots. Binding at saturating free calcium was 65-80 nmol/mg of protein, or 30-40 mol of calcium/mol of enzyme. Aqueous emulsions of lipids extracted from Na+,K+-ATPase yielded dissociation constants and maximum calcium-binding values that were similar to those for native Na+,K+-ATPase. Phospholipase A treatment markedly reduced calcium binding. Pretreatment of native Na+,K+-ATPase with ouabain increased the dissociation constant for calcium binding from 131 +/- 7 to 192 +/- 7 muM without altering maximum calcium binding. Ouabain pretreatment did not affect calcium binding to extracted phospholipids, ouabain-insensitive ATPases, or heat denatured Na+,K+-ATPase, Na+ and K+ (5-20 mM) increased the dissociation constants for calcium, which suggests competition between the monovalent cations and calcium for the binding sites. At higher concentrations of monovalent cations, ouabain increased the apparent affinity of binding sites for calcium. Extrapolation to physiological cation concentrations revealed that the ouabain-induced increase in apparent affinity for calcium may be as much as 2- to 3-fold. These results suggest: (1) calcium binds to phospholipids associated with Na+,K+-ATPase; (2) ouabain interaction with Na+,K+-ATPase induces a perturbation that is transmitted to adjacent phospholipids, altering their affinity for calcium; and (3) at physiological concentrations of Na+ or K+, or both, ouabain interaction with Na+,K+-ATPase may lead to an increased pool of membrane-bound calcium.

Comparison of the Absorption of Calcium Carbonate and Calcium Citrate after Roux-en-Y Gastric Bypass

PubMed Central

Tondapu, P.; Provost, D.; Adams-Huet, B.; Sims, T.; Chang, C.; Sakhaee, K.

2015-01-01

Introduction Roux-en-Y gastric bypass (RYGB) restricts food intake. Consequently, patients consume less calcium. In addition, food no longer passes through the duodenum, the main site of calcium absorption. Therefore, calcium absorption is significantly impaired. The goal of this study is to compare two common calcium supplements in gastric bypass patients. Method Nineteen patients were enrolled in a randomized, double-blinded, crossover study comparing the absorption of calcium from calcium carbonate and calcium citrate salts. Serum and urine calcium levels were assessed for peak values (Cmax) and cumulative calcium increment (area under the curve [AUC]). Serum PTH was assessed for minimum values (PTHmin) and cumulative PTH decrement (AUC). Statistical analysis was performed using a repeated analysis of variance model. Results Eighteen subjects completed the study. Calcium citrate resulted in a significantly higher serum Cmax (9.4+0.4 mg/dl vs. 9.2+0.3 mg/dl, p=0.02) and serum AUC (55+2 mg/dl vs. 54+2 mg/dl, p=0.02). Calcium citrate resulted in a significantly lower PTHmin (24+11 pg/ml vs. 30+13 pg/ml, p=0.01) and a higher AUC (−32+51 pg/ml vs. −3+56 pg/ml, p=0.04). There was a non-significant trend for higher urinary AUC in the calcium citrate group (76.13+36.39 mg/6 h vs. 66.04+40.82, p=0.17). Conclusion Calcium citrate has superior bioavailability than calcium carbonate in RYGB patients. PMID:19437082

Calcium absorption is not increased by caseinophosphopeptides.

PubMed

Teucher, Birgit; Majsak-Newman, Gosia; Dainty, Jack R; McDonagh, David; FitzGerald, Richard J; Fairweather-Tait, Susan J

2006-07-01

One of the suggested health benefits of caseinophosphopeptides (CPPs) is their ability to enhance calcium absorption. This possibility is based on the assumption that they resist proteolysis in the upper gastrointestinal tract and maintain calcium in a soluble form at alkaline pH in the distal ileum. The effects of CPP-enriched preparations (containing candidate functional food ingredients) on calcium absorption from a calcium lactate drink were tested. A randomized crossover trial was undertaken in 15 adults in whom we measured the absorption of calcium from a calcium lactate drink (drink A: 400 mg Ca as lactate) and 2 preparations enriched with forms of CPP (1.7 g each; drinks B and C). Both drinks B and C contained 400 mg Ca as calcium lactate plus approximately 100 mg CPP-derived calcium). Each volunteer received the 3 drinks in random order. Absorption was measured by the dual-label calcium stable-isotope technique. The quantity of calcium absorbed was significantly lower from drink A (103 mg) than from drink B (117 mg; P = 0.012) or drink C (121 mg; P = 0.002), which indicated a positive effect of the CPPs. However, because the CPP preparations contributed additional calcium besides that found in the calcium lactate (drink A), fractional absorption of calcium from drink B (23%) was slightly but significantly (P = 0.015) lower than that from drink A (26%). The differences in calcium absorption are unlikely to have any biological significance. CPPs are unsuitable as candidate ingredients for functional foods that are designed to deliver improved calcium nutrition.

Calcium alloy as active material in secondary electrochemical cell

DOEpatents

Roche, Michael F.; Preto, Sandra K.; Martin, Allan E.

1976-01-01

Calcium alloys such as calcium-aluminum and calcium-silicon, are employed as active material within a rechargeable negative electrode of an electrochemical cell. Such cells can use a molten salt electrolyte including calcium ions and a positive electrode having sulfur, sulfides, or oxides as active material. The calcium alloy is selected to prevent formation of molten calcium alloys resulting from reaction with the selected molten electrolytic salt at the cell operating temperatures.

Ca and Mg isotope constraints on the origin of Earth's deepest δ13 C excursion

NASA Astrophysics Data System (ADS)

Husson, Jon M.; Higgins, John A.; Maloof, Adam C.; Schoene, Blair

2015-07-01

Understanding the extreme carbon isotope excursions found in carbonate rocks of the Ediacaran Period (635-541 Ma), where δ13 C of marine carbonates (δ13 Ccarb) reach their minimum (- 12 ‰) for Earth history, is one of the most vexing problems in Precambrian geology. Known colloquially as the 'Shuram' excursion, the event has been interpreted by many as a product of a profoundly different Ediacaran carbon cycle. More recently, diagenetic processes have been invoked, with the very negative δ13 C values of Ediacaran carbonates explained via meteoric alteration, late-stage burial diagenesis or growth of authigenic carbonates in the sediment column, thus challenging models which rely upon a dramatically changing redox state of the Ediacaran oceans. Here we present 257 δ 44 / 40 Ca and 131 δ26 Mg measurements, along with [Mg], [Mn] and [Sr] data, from carbonates of the Ediacaran-aged Wonoka Formation (Fm.) of South Australia to bring new isotope systems to bear on understanding the 'Shuram' excursion. Data from four measured sections spanning the basin reveal stratigraphically coherent trends, with variability of ∼1.5‰ in δ26 Mg and ∼1.2‰ in δ 44 / 40 Ca. This Ca isotope variability dwarfs the 0.2-0.3 ‰ change seen coeval with the Permian-Triassic mass extinction, the largest recorded in the rock record, and is on par with putative changes in the δ 44 / 40 Ca value of seawater seen over the Phanerozoic Eon. Changes in both isotopic systems are too large to explain with changes in the isotopic composition of Ca and Mg in global seawater given modern budgets and residence times, and thus must be products of alternative processes. Relationships between δ 44 / 40 Ca and [Sr] and δ26 Mg and [Mg] are consistent with mineralogical control (e.g., aragonite vs. calcite, limestone vs. dolostone) on calcium and magnesium isotope variability. The most pristine samples in the Wonoka dataset, preserving Sr concentrations (in the 1000s of ppm range) and δ 44 / 40 Ca values inherited from an originally aragonitic polymorph, have δ13 Ccarb of - 8 ‰ to - 7 ‰ , thereby providing strong geochemical evidence that extremely negative δ13 Ccarb values are primary products of the Ediacaran surface environment.

21 CFR 184.1187 - Calcium alginate.

Code of Federal Regulations, 2014 CFR

2014-04-01

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

21 CFR 184.1191 - Calcium carbonate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium carbonate. 184.1191 Section 184.1191 Food... GRAS § 184.1191 Calcium carbonate. (a) Calcium carbonate (CaCO3, CAS Reg. No. 471-34-1) is prepared by... of calcium carbonate from calcium hydroxide in the “Carbonation process”; or (3) By precipitation of...

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

PubMed

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

2017-12-15

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.

The Hepatitis B Virus X Protein Elevates Cytosolic Calcium Signals by Modulating Mitochondrial Calcium Uptake

PubMed Central

Yang, Bei

2012-01-01

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

Reversible loss of gravitropic sensitivity in maize roots after tip application of calcium chelators

NASA Technical Reports Server (NTRS)

Lee, J. S.; Mulkey, T. J.; Evans, M. L.

1983-01-01

The application of calcium chelating agents (EDTA or EGTA) to the tips of maize roots caused a loss of gravitropic sensitivity. When the chelator was replaced with calcium chloride, gravitropic sensitivity was restored. Asymmetric application of calcium chloride near the tip of a vertical root caused curvature toward the calcium source. When the calcium was applied to the upper surface of the tip of a root oriented horizontally, the root curved upward even though control roots exhibited strong downward curvature. Application of calcium chloride to the tips of decapped roots, which are known to be gravitropically insensitive, did not restore gravitropic sensitivity. However, asymmetric application of calcium chloride near the tips of decapped roots caused curvature toward the calcium source. Calcium may play a key role in linking gravity detection to gravitropic curvature in roots.

Two-pore channels: Regulation by NAADP and customized roles in triggering calcium signals

PubMed Central

Patel, Sandip; Marchant, Jonathan; Brailoiu, Eugen

2010-01-01

NAADP is a potent regulator of cytosolic calcium levels. Much evidence suggests that NAADP activates a novel channel located on an acidic (lysosomal-like) calcium store, the mobilisation of which results in further calcium release from the endoplasmic reticulum. Here, we discuss the recent identification of a family of poorly characterized ion channels (the two-pore channels) as endo-lysosomal NAADP receptors. The generation of calcium signals by these channels is likened to those evoked by depolarisation during excitation-contraction coupling in muscle. We discuss the idea that two pore-channels can mediate a trigger release of calcium which is then amplified by calcium-induced calcium release from the endoplasmic reticulum. This is similar to the activation of voltage-sensitive calcium channels and subsequent mobilisation of sarcoplasmic reticulum calcium stores in cardiac tissue. We suggest that two-pore channels may physically interact with ryanodine receptors to account for more direct release of calcium from the endoplasmic reticulum in analogy with the conformational coupling of voltage-sensitive calcium channels and ryanodine receptors in skeletal muscle. Interaction of two-pore channels with other calcium release channels likely occurs between stores “trans-chatter” and possibly within the same store “cis-chatter”. We also speculate that trafficking of two-pore channels through the endolysosomal system facilitates interactions with calcium entry channels. Strategic placing of two-pore channels thus provides a versatile means of generating spatiotemporally complex cellular calcium signals. PMID:20621760

Barriers to supplemental calcium use among women in suburban family practice: a report from the Cleveland Clinic Ambulatory Research Network (CleAR-eN).

PubMed

Tyler, Carl V; Werner, James J; Panaite, Vanessa; Snyder, Sandra M; Ford, Donald B; Conway, Jessica L; Young, Christopher W; Powell, Brenda L; Smolak, Michael J; Zyzanski, Stephen J

2008-01-01

The majority of adult women in the United States fail to meet daily calcium intake recommendations. This study was undertaken to (1) identify predictors of calcium supplement use versus non-use, (2) understand barriers to calcium supplementation, and (3) determine the potential impact of physician recommendation on calcium supplement use. Surveys were self-administered by 185 women, ages 20 to 64, presenting consecutively for care at 6 suburban community-based family medicine practices within the Cleveland Clinic Ambulatory Research Network (CleAR-eN). We compared demographic characteristics, health beliefs, and health behaviors of those women who reported never using calcium supplements with those who presently took calcium supplements. Women who never took calcium were also queried about reasons for non-use and whether physician recommendation would influence their adoption of calcium supplementation. Multivitamin use, self-perceived risk of osteoporosis, and age were independent predictors of calcium supplement use. Leading barriers for never-users were lack of knowledge about the need/importance of increasing calcium intake, lack of motivation to start supplements, and the belief that their dietary calcium intake alone was sufficient. Ninety-six percent of never-users reported that they would consider taking a calcium supplement if recommended by their physician. Many patient-identified barriers to calcium supplementation seem amenable to focused and brief office-based interventions that could increase the number of women meeting calcium intake guidelines.

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

PubMed

Yu, Ji-Kuen; Pan, Huichin; Huang, Shing-Moo; Huang, Nan-Lan; Yao, Chung-Chin; Hsiao, Kuang-Ming; Wu, Chew-Wun

2013-01-01

Our aim was to investigate the calcium content of different gallstone compositions and the pathogenic mechanisms of calcium carbonate gallstones. Between August 2001 and July 2007, gallstones from 481 patients, including 68 calcium carbonate gallstones, were analyzed for total calcium content. Gallbladder bile samples from 33 cases and six controls were analyzed for pH, carbonate anion level, free-ionized calcium concentration and saturation index for calcium carbonate. Total calcium content averaged 75.6 %, 11.8 %, and 4.2 % for calcium carbonate, calcium bilirubinate and cholesterol gallstones. In 29.4 % of patients, chronic and/or intermittent cystic duct obstructions were caused by polypoid lesions in the neck region and 70.6 % were caused by stones. A total of 82 % of patients had chronic low-grade inflammation of the gallbladder wall and 18.0 % had acute inflammatory exacerbations. In the bile, we found the mean pH, mean carbonate anion, free-ionized calcium concentrations, and mean saturation index for calcium carbonate to be elevated in comparison to controls. 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_CaCO(3) from 1 to 22.4. Thus, in an alkaline milieu with pH 7.8, calcium carbonate begins to aggregate and precipitate. Copyright © 2012. Published by Elsevier B.V.

[The dynamics of calcium distribution in stigma and style of lettuce (Lactuca sativa L.) before and after pollination].

PubMed

Qiu, Yi Lan; Liu, Ru Shi; Xie, Chao Tian; Yang, Yan Hong; Gu, Li; Tian, Hui Qiao

2005-08-01

Potassium antimonite was used to deposit calcium in the stigma and style of lettuce (Lactuca sativa L.) before and after pollination. The stigma of lettuce is two splits. Abundant calcium granules are displayed in the wall of papillae on the receptive surface of stigma before and after pollination, which may facilitate pollen germination. However, a few calcium granules in the wall of epidermis cell on no-receptive surface. Calcium distribution in style presents a gradient in transmitting tissue and parenchyma cells from the top to the base of the style before pollination. After pollination, calcium in transmitting tissue distinctly increased and its gradient distribution became more evident. Pollen tubes grow in the intercellular gaps of transmitting tissue. When pollen tubes grew into transmitting tissue, calcium granules in parenchyma around transmitting tissue decreased, suggesting a calcium movement was controlled by pollen tubes. The calcium gradient distribution also appeared in the trachea of vascular bundle of style. In general, calcium in style displays a feature of time-special distribution: transmitting tissue doesn't need much more calcium that is only stored in the parenchyma before pollination. However, calcium in parenchyma cells may be transported to transmitting tissue and make the latter contain more calcium to form an evident calcium gradient and meet the requirement of pollen tubes directionally growing after pollination. This is the second sample of calcium gradient existing in style, which was found by using potassium antimonite method.

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

NASA Technical Reports Server (NTRS)

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

1995-01-01

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

Biotic Nitrogen Enrichment Regulates Calcium Sources to Forests

NASA Astrophysics Data System (ADS)

Pett-Ridge, J. C.; Perakis, S. S.; Hynicka, J. D.

2015-12-01

Calcium is an essential nutrient in forest ecosystems that is susceptible to leaching loss and depletion. Calcium depletion can affect plant and animal productivity, soil acid buffering capacity, and fluxes of carbon and water. Excess nitrogen supply and associated soil acidification are often implicated in short-term calcium loss from soils, but the long-term role of nitrogen enrichment on calcium sources and resupply is unknown. Here we use strontium isotopes (87Sr/86Sr) as a proxy for calcium to investigate how soil nitrogen enrichment from biological nitrogen fixation interacts with bedrock calcium to regulate both short-term available supplies and the long-term sources of calcium in montane conifer forests. Our study examines 22 sites in western Oregon, spanning a 20-fold range of bedrock calcium on sedimentary and basaltic lithologies. In contrast to previous studies emphasizing abiotic control of weathering as a determinant of long-term ecosystem calcium dynamics and sources (via bedrock fertility, climate, or topographic/tectonic controls) we find instead that that biotic nitrogen enrichment of soil can strongly regulate calcium sources and supplies in forest ecosystems. For forests on calcium-rich basaltic bedrock, increasing nitrogen enrichment causes calcium sources to shift from rock-weathering to atmospheric dominance, with minimal influence from other major soil forming factors, despite regionally high rates of tectonic uplift and erosion that can rejuvenate weathering supply of soil minerals. For forests on calcium-poor sedimentary bedrock, we find that atmospheric inputs dominate regardless of degree of nitrogen enrichment. Short-term measures of soil and ecosystem calcium fertility are decoupled from calcium source sustainability, with fundamental implications for understanding nitrogen impacts, both in natural ecosystems and in the context of global change. Our finding that long-term nitrogen enrichment increases forest reliance on atmospheric calcium helps explain reports of greater ecological calcium limitation in an increasingly nitrogen-rich world.

Evidence for a Regulatory Role of Calcium in Gravitropism

NASA Technical Reports Server (NTRS)

Roux, S. J.

1983-01-01

Experiments conducted to determine the cellular basis of gravitropism, the phenomenon of calcium migration following gravitropic stimulation, and the preferential accumulation of calcium in cells are described. Results of autoradiographic studies of cross sections of oat, and the pryoantimony precipitation of calcium in situ are discussed. It was found that the movement of calcium during gravimetric stimulation is a redistribution of calcium from the vacuolar regions into the cells walls. This movement requires precipitation of a calcium ATPase. The control of calcium ATPase by calmodulin and whether chlorpromazine is binding to calmodulin in plants are considered.

Dietary Calcium Intake, Serum Calcium Level, and their Association with Preeclampsia in Rural North India

PubMed Central

Gupta, Anant; Kant, Shashi; Pandav, Chandrakant S.; Gupta, Sanjeev K.; Rai, Sanjay K.; Misra, Puneet

2016-01-01

Background: Preeclampsia in pregnancy has been shown to be associated with low serum calcium level. Though the evidence is abundant, it is equivocal. Objectives: The study aimed to estimate the dietary calcium intake and serum calcium status among pregnant women, and to document the association of the dietary calcium intake and serum calcium status with incidence of preeclampsia in the 3rd trimester of pregnancy. Materials and Methods: A community-based cross-sectional study was conducted in the Health and Demographic Surveillance System (HDSS) site, Ballabgarh, Haryana, India. All pregnant women between 28 weeks and 36 weeks of gestation were interviewed. A semi-structured interview schedule and a 24-h dietary recall questionnaire were administered to assess the dietary calcium intake. AutoAnalyser (Biolis 24i) was used for measuring serum calcium. Results: We enrolled 217 pregnant women. The mean [standard deviation (SD)] dietary calcium intake was 858 (377) mg/day. The mean (SD) serum calcium level was 9.6 mg/dL (0.56). Incidence of preeclampsia was 13.4%. Preeclampsia was not associated with hypocalcemia [odds ratio (OR) = 1.2 95% confidence interval (CI); 0.27-3.98]. Conclusion: The majority of pregnant women had inadequate dietary calcium intake. The prevalence of hypocalcemia was low. Low serum calcium level was not associated with preeclampsia. Calcium supplementation may not reduce preeclampsia in this population. PMID:27385877

Teaching Calcium-Induced Calcium Release in Cardiomyocytes Using a Classic Paper by Fabiato

ERIC Educational Resources Information Center

Liang, Willmann

2008-01-01

This teaching paper utilizes the materials presented by Dr. Fabiato in his review article entitled "Calcium-induced release of calcium from the cardiac sarcoplasmic reticulum." In the review, supporting evidence of calcium-induced calcium release (CICR) is presented. Data concerning potential objections to the CICR theory are discussed as well. In…

Factors to consider in the selection of a calcium supplement.

PubMed Central

Shangraw, R F

1989-01-01

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 supplements should be taken with meals to ensure solubility. Calcium carbonate, and particularly tribasic calcium phosphate tablets, are not recommended for patients with achlorhydria. Calcium tablets, like almost all drugs, should be taken with 8 ounces of water or other liquid. PMID:2517700

Dependency of Calcium Alternans on Ryanodine Receptor Refractoriness

PubMed Central

Alvarez-Lacalle, Enric; Cantalapiedra, Inma R.; Peñaranda, Angelina; Cinca, Juan; Hove-Madsen, Leif; Echebarria, Blas

2013-01-01

Background Rapid pacing rates induce alternations in the cytosolic calcium concentration caused by fluctuations in calcium released from the sarcoplasmic reticulum (SR). However, the relationship between calcium alternans and refractoriness of the SR calcium release channel (RyR2) remains elusive. Methodology/Principal Findings To investigate how ryanodine receptor (RyR2) refractoriness modulates calcium handling on a beat-to-beat basis using a numerical rabbit cardiomyocyte model. We used a mathematical rabbit cardiomyocyte model to study the beat-to-beat calcium response as a function of RyR2 activation and inactivation. Bi-dimensional maps were constructed depicting the beat-to-beat response. When alternans was observed, a novel numerical clamping protocol was used to determine whether alternans was caused by oscillations in SR calcium loading or by RyR2 refractoriness. Using this protocol, we identified regions of RyR2 gating parameters where SR calcium loading or RyR2 refractoriness underlie the induction of calcium alternans, and we found that at the onset of alternans both mechanisms contribute. At low inactivation rates of the RyR2, calcium alternans was caused by alternation in SR calcium loading, while at low activation rates it was caused by alternation in the level of available RyR2s. Conclusions/Significance We have mapped cardiomyocyte beat-to-beat responses as a function of RyR2 activation and inactivation, identifying domains where SR calcium load or RyR2 refractoriness underlie the induction of calcium alternans. A corollary of this work is that RyR2 refractoriness due to slow recovery from inactivation can be the cause of calcium alternans even when alternation in SR calcium load is present. PMID:23390511

Serum calcium and incident diabetes: an observational study and meta-analysis.

PubMed

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

2016-05-01

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.

A comparative study of calcium absorption following a single serving administration of calcium carbonate powder versus calcium citrate tablets in healthy premenopausal women

PubMed Central

Wang, Haiyuan; Bua, Peter; Capodice, Jillian

2014-01-01

Background Calcium is an essential mineral often taken as a daily, long-term nutritional supplement. Data suggests that once-daily dosing is important with regard to long-term compliance of both drugs and nutritional supplements. Objective This study was undertaken to compare the bioavailability of a single serving of two calcium supplements in healthy, premenopausal women. Design A two-period, crossover bioavailability study of a single serving of calcium citrate tablets (two tablets=500 mg calcium) versus a single serving of calcium carbonate powder (one packet of powder=1,000 mg calcium) was performed in healthy women aged between 25 and 45. All subjects were on a calcium-restricted diet 7 days prior to testing and fasted for 12 h before being evaluated at 0, 1, 2, and 4 h after oral administration of the test agents. Blood measurements for total and ionized calcium and parathyroid hormone were performed and adverse events were monitored. Results Twenty-three women were evaluable with a mean age of 33.2±8.71. Results showed that administration of a single serving of a calcium carbonate powder resulted in greater absorption in total and ionized calcium versus a single serving of calcium citrate tablets at 4 h (4.25±0.21 vs. 4.16±0.16, p=0.001). There were minimal side effects and no reported serious adverse events. Conclusions This study shows that a single serving of a calcium carbonate powder is more bioavailable than a single serving of calcium citrate tablets. This may be beneficial for long-term compliance. PMID:24772062

Fast calcium transients translate the distribution and conduction of neural activity in different regions of a single sensory neuron.

PubMed

Purali, Nuhan

2017-09-01

In the present study, cytosolic calcium concentration changes were recorded in response to various forms of excitations, using the fluorescent calcium indicator dye OG-BAPTA1 together with the current or voltage clamp methods in stretch receptor neurons of crayfish. A single action potential evoked a rise in the resting calcium level in the axon and axonal hillock, whereas an impulse train or a large saturating current injection would be required to evoke an equivalent response in the dendrite region. Under voltage clamp conditions, amplitude differences between axon and dendrite responses vanished completely. The fast activation time and the modulation of the response by extracellular calcium concentration changes indicated that the evoked calcium transients might be mediated by calcium entry into the cytosol through a voltage-gated calcium channel. The decay of the responses was slow and sensitive to extracellular sodium and calcium concentrations as well as exposure to 1-10 mM NiCl 2 and 10-500 µM lanthanum. Thus, a sodium calcium exchanger and a calcium ATPase might be responsible for calcium extrusion from the cytosol. Present results indicate that the calcium indicator OG-BAPTA1 might be an efficient but indirect way of monitoring regional membrane potential differences in a single neuron.

The effects of excess calcium on the handling and mechanical properties of hydrothermal derived calcium phosphate bone cement

NASA Astrophysics Data System (ADS)

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

2018-01-01

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.

Antenatal calcium intake in Malaysia.

PubMed

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

2014-04-01

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.

Calcium Bioavailability from Mineral Waters with Different Mineralization in Comparison to Milk and a Supplement.

PubMed

Greupner, Theresa; Schneider, Inga; Hahn, Andreas

2017-07-01

The aim of the present study was to compare the bioavailability of calcium from 3 mineral waters with different concentrations of minerals with that of milk and a calcium supplement. A single-center, randomized controlled trial with a crossover design with 21 healthy men and women was conducted at the Institute of Food Science and Human Nutrition, Leibniz University Hannover. The participants consumed the 5 test products providing 300 mg of calcium each on 5 examination days with 1-week wash-out phases in between. Primary outcome variables were the area under the curve of serum calcium levels for 10-hour (AUC 0-10h ) and 24-hour urinary calcium excretion. In all groups, no significant differences in the AUC 0-10h of serum calcium levels as well as in the 24-hour urinary calcium excretion were observed. Likewise, mean changes in serum phosphate and urinary phosphate, as well as serum parathormone, showed no differences between the groups. Given an equivalent bioavailability of calcium in all test products, neither a high concentration of SO 4 2- or of HCO 3 influenced the bioavailability of calcium. Accordingly, the use of mineral water with high concentrations of calcium constitutes a calorie-free calcium source that can improve calcium supply.

40 CFR 415.50 - Applicability; description of the calcium oxide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... 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. ...

40 CFR 415.50 - Applicability; description of the calcium oxide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... 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. ...

40 CFR 415.50 - Applicability; description of the calcium oxide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... 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. ...

40 CFR 415.50 - Applicability; description of the calcium oxide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... 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. ...

40 CFR 415.50 - Applicability; description of the calcium oxide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... 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. ...

Protection of Dentate Hilar Cells from Prolonged Stimulation by Intracellular Calcium Chelation

NASA Astrophysics Data System (ADS)

Scharfman, Helen E.; Schwartzkroin, Philip A.

1989-10-01

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.

Lack of voltage-dependent calcium channel opening during the calcium influx induced by progesterone in human sperm. Effect of calcium channel deactivation and inactivation.

PubMed

Guzmán-Grenfell, Alberto Martín; González-Martínez, Marco T

2004-01-01

Progesterone induces calcium influx and acrosomal exocytosis in human sperm. Pharmacologic evidence suggests that voltage-dependent calcium channels (VDCCs) are involved. In this study, membrane potential (Vm) and intracellular calcium concentration ([Ca(2+)](i)) were monitored simultaneously to assess the effect of VDCC gating on the calcium influx triggered by progesterone. Holding the Vm to values that maintained VDCCs in a deactivated (-71 mV) closed state inhibited the calcium influx induced by progesterone by approximately 40%. At this Vm, the acrosomal reaction induced by progesterone, but not by A23187, was inhibited. However, when the Vm was held at -15 mV (which maintains VDCCs in an inactivated closed state), the progesterone-induced calcium influx was stimulated. Furthermore, the progesterone and voltage-dependent calcium influxes were additive. These findings indicate that progesterone does not produce VDCC gating in human sperm.

[Calcium and magnesium concentrations in "Healthy" and lithiasic human kidney (author's transl)].

PubMed

Terhorst, B; Stoeppler, M

1976-07-01

Calcium and magnesium levels in the cortex, medulla, and papilla of human kidney from 32 so-called healthy patients and from eleven patients with calcium-oxalate lithiasis were determined by atom-absorption spectralphotometry. A positive calcium gradient with the highest calcium concentration in the papilla was found in all kidneys. Compared to the control group, that calcium concentration in the lithiasic kidneys was reduced by 50% in the papilla, but in the cortex and medulla, the levels were the same. A relative depletion of calcium in the papilla in hypercalciuria goes against the theory that the papilla is the main center of development of calcium-containing stones. The magnesium concentration was practically the same in cortex, medulla, and papilla, and no significant difference was found between lithiasic and healthy kidneys. These findings underline the central role of calcium in the genesis of calcium-containing stones.

Separation of hemicellulose-derived saccharides from wood hydrolysate by lime and ion exchange resin.

PubMed

Wang, Xiaojun; Zhuang, Jingshun; Fu, Yingjuan; Tian, Guoyu; Wang, Zhaojiang; Qin, Menghua

2016-04-01

A combined process of lime treatment and mixed bed ion exchange was proposed to separate hemicellulose-derived saccharides (HDS) from prehydrolysis liquor (PHL) of lignocellulose as value added products. The optimization of lime treatment achieved up to 44.2% removal of non-saccharide organic compounds (NSOC), mainly colloidal substances, with negligible HDS degradation at 0.5% lime level and subsequent neutralization by phosphoric acid. The residual NSOC and calcium ions in lime-treated PHL were eliminated by mixed bed ion exchange. The breakthrough curves of HDS and NSOC showed selective retention toward NSOC, leading to 75% HDS recovery with 95% purity at 17 bed volumes of exchange capacity. In addition, macroporous resin showed higher exchange capacity than gel resin as indicated by the triple processing volume. The remarkable selectivity of the combined process suggested the feasibility for HDS separation from PHL. Copyright © 2016 Elsevier Ltd. All rights reserved.

Chemical composition and antibacterial activity of Opuntia ficus-indica f. inermis (cactus pear) flowers.

PubMed

Ennouri, Monia; Ammar, Imene; Khemakhem, Bassem; Attia, Hamadi

2014-08-01

Opuntia ficus-indica f. inermis (cactus pear) flowers have wide application in folk medicine. However, there are few reports focusing on their biological activity and were no reports on their chemical composition. The nutrient composition and hexane extracts of Opuntia flowers at 4 flowering stages and their antibacterial and antifungal activities were investigated. The chemical composition showed considerable amounts of fiber, protein, and minerals. Potassium (K) was the predominant mineral followed by calcium (Ca), magnesium (Mg), sodium (Na), iron (Fe), and zinc (Zn). The main compounds in the various hexane extracts were 9.12-octadecadienoic acid (29-44%) and hexadecanoic acid (8.6-32%). The antibacterial activity tests showed that O. inermis hexane extracts have high effectiveness against Escherichia coli and Staphylococcus aureus, making this botanical source a potential contender as a food preservative or food control additive.

An in vitro study on the effect of TiF(4) treatment against erosion by hydrochloric acid on pellicle-covered enamel.

PubMed

Hove, L H; Young, A; Tveit, A B

2007-01-01

The aim of this in vitro study was to examine the effect of fluoride treatment on pellicle-covered enamel exposed to an acidic challenge simulating gastric reflux. Sixteen bovine and 16 human teeth were sectioned into four pieces, divided into four groups: (1) control, (2) 2-hour pellicle, (3) TiF(4), and (4) 2-hour pellicle + TiF(4), and subsequently subjected to 3 ml 0.01 M HCl stepwise for 4 + 4 + 4 min. The acid was analysed for calcium by atomic absorption spectroscopy. TiF(4) reduced Ca release from enamel by 76, 57 and 56% following the 4 + 4 + 4-min acid exposures, respectively, in bovine and 44, 54 and 54% in human enamel. These results suggest that treatment of enamel with a TiF(4) solution, with or without pellicle removal, may provide protection for the enamel against acid attack.

[Inclusion of proteins into polyelectrolyte microcapsules by coprecipitation and adsorption].

PubMed

Kochetkova, O Iu; Kazakova, L I; Moshkov, D A; Vinokurov, M G; Shabarchina, L I

2013-01-01

In present study microcapsules composed of synthetic (PSS and PAA) and biodegradable (DS and PAr) polyelectrolytes on calcium carbonate microparticles were obtained. The ultrastructural organization of biodegradable microcapsules was studied using transmission electron microscopy. The envelope of such capsules consisting of six polyelectrolyte layers is already well-formed, having the average thickness of 44 ± 3.0 nm, and their internal polyelectrolyte matrix is sparser compared to the synthetic microcapsules. Spectroscopy was employed to evaluate the efficiency of incorporation of FITC-labeled BSA into synthetic microcapsules by adsorption, depending on the number of polyelectrolyte layers. It was shown that the maximal amount of protein incorporated into the capsules with 6 or 7 polyelectrolyte layers (4 and 2 pg/capsule, correspondingly). As a result we conclude that, in comparison with co-precipitation, the use of adsorption allows to completely avoid the loss of protein upon encapsulation.

Aluminium Involvement in Neurotoxicity

PubMed Central

Fulgenzi, Alessandro; Vietti, Daniele; Ferrero, Maria Elena

2014-01-01

The aetiology of neurodegenerative diseases (ND) seems to involve susceptibility genes and environmental factors. Toxic metals are considered major environmental pollutants. Following our study of a case of multiple sclerosis (MS) improvement due to removal of aluminium (Al) and other toxic metals, we have examined the possible relationship between Al intoxication and ND. We used the slow intravenous treatment with the chelating agent EDTA (calcium disodium ethylene diamine tetraacetic acid) (chelation test) to remove Al and detected it in the urine collected from the patients for 12 hours. Patients affected by MS represented 85.6% of total ND. Al was present in 44.8% of cases comprehensive of ND and healthy patients. Al levels were significantly higher in ND patients than in healthy subjects. We here show that treatment of patients affected by Al burden with ten EDTA chelation therapies (EDTA intravenous administration once a week) was able to significantly reduce Al intoxication. PMID:25243176

Preparation of C.I. Pigment 52:1 anion-pillared layered double hydroxide and the thermo- and photostability of the resulting intercalated material

NASA Astrophysics Data System (ADS)

Guo, Shengchang; Evans, David G.; Li, Dianqing

2006-05-01

Intercalation of 2-naphthalenecarboxylic acid, 4-((4-chloro-5-methyl-2-sulfophenyl) azo)-3-hydroxy-, calcium salt (1:1) (C.I. Pigment Red 52:1, also known as New Rubine S6B) into a layered double hydroxide (LDHs) host was carried out using MgAl NO3 LDHs as a precursor in an effort to improve the thermal and photo stability of the pigment. After intercalation, the powder X-ray diffraction (XRD) pattern shows that the basal spacing of the LDHs increased from 0.86 to 1.92 nm. Infrared spectra and TG DTA curves demonstrate that there are supramolecular host guest interactions. It was found that the intercalated material is more stable than the pristine pigment at high temperatures. The pigment anion-pillared LDHs also exhibit much higher photostablity to UV-light than the pristine pigment.

A proteomics study of hyperhomocysteinemia injury of the hippocampal neurons using iTRAQ.

PubMed

Fang, Min; Wang, Jing; Yan, Han; Zhao, Yan-Xin; Liu, Xue-Yuan

2014-11-01

High levels of homocysteine, caused by abnormal methionine metabolism, can induce degeneration of mouse hippocampal neurons. iTRAQ™ technology has been widely used in the field of proteomics research and through employing this technology, the present study identified that hyperhomocysteinemia induced the downregulation of 52 proteins and upregulation of 44 proteins in the mouse hippocampus. Through gene ontology and pathway analysis, the upregulation of components of the cytoskeleton, actin, regulators of focal adhesion, calcium signaling pathways, tight junctions, ErbB and gonadotrophin‑releasing hormone signaling, leukocyte, transendothelial migration, propanoate and pyruvate metabolism, valine, leucine and isoleucine biosynthesis, synthesis and degradation of ketone bodies and benzoate degradation via CoA ligation pathway, was identified. It was additionally verified that tau protein was highly expressed in the hyperhomocysteinemic neurons. Further analysis revealed that tau network proteins played functional roles in homocysteine‑induced neuronal damage.

Calcium bodies of Titanethes albus (Crustacea: Isopoda): molt-related structural dynamics and calcified matrix-associated bacteria.

PubMed

Vittori, Miloš; Kostanjšek, Rok; Znidaršič, Nada; Zagar, Kristina; Ceh, Miran; Strus, Jasna

2012-10-01

Crustaceans form a variety of calcium deposits in which they store calcium necessary for the mineralization of their exoskeletons. Calcium bodies, organs containing large amounts of calcium, have been reported in some terrestrial isopod crustaceans, but have not yet been extensively studied. We analyzed the architecture of these organs during the molt cycle in the isopod Titanethes albus. Two pairs of calcium bodies are positioned ventrolaterally in posterior pereonites of T. albus. Individual organs are epithelial sacs that contain material arranged in concentric layers delimited by thin laminae. As demonstrated by electron microscopy and fluorescence in situ hybridization, abundant bacteria are present within the calcium bodies. Regardless of the molt cycle stage, crystalline concretions are present in the central areas of the calcium bodies. Energy dispersive X-ray spectrometry of the concretions demonstrated that they are composed predominantly of calcium and phosphorus and selected area electron diffraction indicated the presence of hydroxyapatite. In molting animals, a glassy layer of mineralized matrix is formed between the envelope and the outermost lamina of the calcium body. This layer consists of an amorphous calcium mineral which contains less phosphorus than the central concretions and is resorbed after molt. Since changes in the mineralized matrix are synchronized with the molt cycle, the calcium bodies likely function as a storage compartment that complements sternal deposits as a source of calcium for the mineralization of the exoskeleton. Bacteria associated with the mineralized matrix of calcium bodies are evidently involved in calcium dynamics. Copyright © 2012 Elsevier Inc. All rights reserved.

Exopolysaccharides regulate calcium flow in cariogenic biofilms

PubMed Central

Varenganayil, Muth M.; Decho, Alan W.

2017-01-01

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

Nitroaryl-1,4-dihydropyridines as antioxidants against rat liver microsomes oxidation induced by iron/ascorbate, nitrofurantoin and naphthalene.

PubMed

Letelier, María Eugenia; Entrala, Paz; López-Alarcón, Camilo; González-Lira, Víctor; Molina-Berríos, Alfredo; Cortés-Troncoso, Juan; Jara-Sandoval, José; Santander, Paola; Núñez-Vergara, Luis

2007-12-01

1,4-Dihydropyridines (DHPs) used in the treatment of cardiovascular diseases, are calcium channel antagonists and also antioxidant agents. These drugs are metabolized through cytochrome P(450) oxidative system, majority localized in the hepatic endoplasmic reticulum. Several lipophilic drugs generate oxidative stress to be metabolized by this cellular system. Thus, DHP antioxidant properties may prevent the oxidative stress associated with hepatic biotransformation of drugs. In this work, we tested the antioxidant capacity of several synthetic nitro-phenyl-DHPs. These compounds (I-IV) inhibited the microsomal lipid peroxidation, UDPGT oxidative activation and microsomal thiols oxidation; all phenomena induced by Fe(3+)/ascorbate, a generator system of oxygen free radicals. As the same manner, these compounds inhibited the oxygen consumption induced by Cu(2+)/ascorbate in the absence of microsomes. Furthermore, compound III (2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridin-3,5-ethyl-dicarboxylate) and compound V (N-ethyl-2,6-dimethyl-4-(4-nitrophenyl)-1,4-dihydropyridin-3,5-methyl-dicarboxylate) inhibited the microsomal lipid peroxidation induced by Nitrofurantoin and naphthalene in the presence of NADPH. Oxidative stress induced on endoplasmic reticulum may alter the biotransformation of drugs, so, modifying their plasmatic concentrations and therapeutic effects. When drugs which are activated by biotransformation are administered together with antioxidant drugs, such as DHPs, oxidative stress induced in situ may be prevented.

Unenhanced CT findings can predict the development of urinary calculi in stone-free patients.

PubMed

Ciudin, Alexandru; Luque Galvez, Maria Pilar; Salvador Izquierdo, Rafael; Franco de Castro, Agustin; Garcia-Cruz, Eduardo; Alcover García, Juan; Alvarez-Vijande García, Jose Ricardo; Nicolau, Carlos; Alcaraz Asensio, Antonio

2012-09-01

To determine if calcium deposits in the papillae can be identified by unenhanced computed tomography (uCT) even before renal stones develop. A retrospective review of 413 patients with calculi identified 31 patients (stone-forming group) with a history of urinary tract calculi with a calculus demonstrated by uCT and a stone-free uCT before calculi had developed. The control group (n = 31) was composed of live kidney donors with no history of calculi and a stone-free uCT. CT attenuation was measured in all CTs using two regions of interest of 0.05 cm(2) and 0.1 cm(2) over the tip and the neighbouring area of the papillae. Student's and Wilcoxon t-tests were used for comparing results in the two groups. The attenuation of the tip of the papilla was higher in the stone-forming group when compared to the controls after (45.2 HU versus 32.1 HU, P = 0.001) and even before frank calculi had developed (44.2 HU versus 32.1 HU, P = 0.003). There was no significant difference in papillary attenuation in the stone group before and after calculi had developed (45.2 HU versus 44.2 HU, P = 0.82). Stone-forming patients exhibit higher papillary density even before calculi develop. This could define a population at risk of developing calculi.

40 CFR 415.30 - Applicability; description of the calcium carbide production subcategory.

Code of Federal Regulations, 2010 CFR

2010-07-01

... calcium carbide production subcategory. 415.30 Section 415.30 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.30 Applicability; description of the calcium... the production of calcium carbide in uncovered furnaces. ...

40 CFR 415.30 - Applicability; description of the calcium carbide production subcategory.

Code of Federal Regulations, 2011 CFR

2011-07-01

... calcium carbide production subcategory. 415.30 Section 415.30 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.30 Applicability; description of the calcium... the production of calcium carbide in uncovered furnaces. ...

40 CFR 415.30 - Applicability; description of the calcium carbide production subcategory.

Code of Federal Regulations, 2012 CFR

2012-07-01

... calcium carbide production subcategory. 415.30 Section 415.30 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.30 Applicability; description of the calcium... the production of calcium carbide in uncovered furnaces. ...

40 CFR 415.30 - Applicability; description of the calcium carbide production subcategory.

Code of Federal Regulations, 2014 CFR

2014-07-01

... calcium carbide production subcategory. 415.30 Section 415.30 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.30 Applicability; description of the calcium... the production of calcium carbide in uncovered furnaces. ...

40 CFR 415.30 - Applicability; description of the calcium carbide production subcategory.

Code of Federal Regulations, 2013 CFR

2013-07-01

... calcium carbide production subcategory. 415.30 Section 415.30 Protection of Environment ENVIRONMENTAL... SOURCE CATEGORY Calcium Carbide Production Subcategory § 415.30 Applicability; description of the calcium... the production of calcium carbide in uncovered furnaces. ...

Multitrophic effects of calcium availability on invasive alien plants, birds, and bird prey items

Treesearch

Vince D' Amico; Greg Shriver; Jake Bowman; Meg Ballard; Whitney Wiest; Liz Tymkiw; Melissa Miller

2011-01-01

Acid rain alters forest soil calcium concentrations in two ways: (1) hydrogen ions displace exchangeable calcium adsorbed to soil surfaces, and (2) aluminum is released to soil water by acid rain and displaces adsorbed calcium. This increases the absorption of aluminum by plant roots, and decreases the absorption of calcium, causing calcium to be more readily leached...

Study on the Equilibrium Between Liquid Iron and Calcium Vapor

NASA Astrophysics Data System (ADS)

Berg, Martin; Lee, Jaewoo; Sichen, Du

2017-06-01

The solubility of calcium in liquid iron at 1823 K and 1873 K (1550 °C and 1600 °C) as a function of calcium potential was studied experimentally. The measurements were performed using a closed molybdenum holder in which liquid calcium and liquid iron were held at different temperatures. The results indicate a linear relationship between the activity of calcium, relative to pure liquid calcium, and the mole fraction of dissolved calcium in liquid iron, with a negligible temperature dependency in the ranges studied. The activity coefficient of calcium in liquid iron at infinite dilution, γ_{Ca(l0°, was calculated as 1551.

Effect of limestone reactivity and percent on production by dairy cows in early lactation.

PubMed

Nocek, J E; Braund, D G; English, J E

1983-12-01

Seventy-two Holstein cows (16 first lactation) were assigned to four treatments: A) normal-grind limestone (800 to 1000 mu) added to provide .77% calcium (total ration dry basis); B) fine-grind limestone (less than 150 mu) at .77% calcium; C) normal-grind at 1.15% calcium; and D) fine-grind limestone at 1.15% calcium. Cows fed diets containing .77% calcium had higher percent milk fat and fat yield than those fed 1.15% calcium diets, and cows fed fine-grind limestone had greater percent fat and fat yield than those fed normal-grind limestone. Four percent fat-corrected milk was higher for cows fed .77% calcium diets. Trends were similar for heifers in first lactation. Dry matter intake was higher for cows fed .77% calcium diets, and nutrient efficiency for milk synthesis favored cows fed fine-grind 1.15% calcium. Fecal pH was higher during wk 4 on treatment for cows fed high calcium diets; however, 8 wk were not different. Fecal starch and calcium and phosphorus in plasma were not different between treatments: however, heifers fed fine-grind 1.15% calcium showed a decrease of fecal starch with time.

Regulation of calcium signals in the nucleus by a nucleoplasmic reticulum

PubMed Central

Echevarría, Wihelma; Leite, M. Fatima; Guerra, Mateus T.; Zipfel, Warren R.; Nathanson, Michael H.

2013-01-01

Calcium is a second messenger in virtually all cells and tissues1. Calcium signals in the nucleus have effects on gene transcription and cell growth that are distinct from those of cytosolic calcium signals; however, it is unknown how nuclear calcium signals are regulated. Here we identify a reticular network of nuclear calcium stores that is continuous with the endoplasmic reticulum and the nuclear envelope. This network expresses inositol 1,4,5-trisphosphate (InsP3) receptors, and the nuclear component of InsP3-mediated calcium signals begins in its locality. Stimulation of these receptors with a little InsP3 results in small calcium signals that are initiated in this region of the nucleus. Localized release of calcium in the nucleus causes nuclear protein kinase C (PKC) to translocate to the region of the nuclear envelope, whereas release of calcium in the cytosol induces translocation of cytosolic PKC to the plasma membrane. Our findings show that the nucleus contains a nucleoplasmic reticulum with the capacity to regulate calcium signals in localized subnuclear regions. The presence of such machinery provides a potential mechanism by which calcium can simultaneously regulate many independent processes in the nucleus. PMID:12717445

Idiopathic hypercalciuria and formation of calcium renal stones

PubMed Central

Coe, Fredric L.; Worcester, Elaine M.; Evan, Andrew P.

2018-01-01

The most common presentation of nephrolithiasis is idiopathic calcium stones in patients without systemic disease. Most stones are primarily composed of calcium oxalate and form on a base of interstitial apatite deposits, known as Randall’s plaque. By contrast some stones are composed largely of calcium phosphate, as either hydroxyapatite or brushite (calcium monohydrogen phosphate), and are usually accompanied by deposits of calcium phosphate in the Bellini ducts. These deposits result in local tissue damage and might serve as a site of mineral overgrowth. Stone formation is driven by supersaturation of urine with calcium oxalate and brushite. The level of supersaturation is related to fluid intake as well as to the levels of urinary citrate and calcium. Risk of stone formation is increased when urine citrate excretion is <400 mg per day, and treatment with potassium citrate has been used to prevent stones. Urine calcium levels >200 mg per day also increase stone risk and often result in negative calcium balance. Reduced renal calcium reabsorption has a role in idiopathic hypercalciuria. Low sodium diets and thiazide-type diuretics lower urine calcium levels and potentially reduce the risk of stone recurrence and bone diseas PMID:27452364

The Yin and Yang of Calcium Effects on Synaptic Vesicle Endocytosis

PubMed Central

Wu, Xin-Sheng

2014-01-01

A large number of studies suggest that calcium triggers and accelerates vesicle endocytosis at many synapses and non-neuronal secretory cells. However, many studies show that prolonging the duration of the stimulation train, which induces more calcium influx, slows down endocytosis; and several studies suggest that instead of triggering endocytosis, calcium actually inhibits endocytosis. Here we addressed this apparent conflict at a large nerve terminal, the calyx of Held in rat brainstem, in which recent studies suggest that transient calcium increase up to tens of micromolar concentration at the micro/nano domain triggers endocytosis. By dialyzing 0–1 μm calcium into the calyx via a whole-cell pipette, we found that slow endocytosis was inhibited by calcium dialysis in a concentration-dependent manner. Thus, prolonged, small, and global calcium increase inhibits endocytosis, whereas transient and large calcium increase at the micro/nano domain triggers endocytosis and facilitates endocytosis. This yin and yang effect of calcium may reconcile apparent conflicts regarding whether calcium accelerates or inhibits endocytosis. Whether endocytosis is fast or slow depends on the net outcome between the yin and yang effect of calcium. PMID:24523554

Activity-dependent ATP-waves in the mouse neocortex are independent from astrocytic calcium waves.

PubMed

Haas, Brigitte; Schipke, Carola G; Peters, Oliver; Söhl, Goran; Willecke, Klaus; Kettenmann, Helmut

2006-02-01

In the corpus callosum, astrocytic calcium waves propagate via a mechanism involving ATP-release but not gap junctional coupling. In the present study, we report for the neocortex that calcium wave propagation depends on functional astrocytic gap junctions but is still accompanied by ATP-release. In acute slices obtained from the neocortex of mice deficient for astrocytic expression of connexin43, the calcium wave did not propagate. In contrast, in the corpus callosum and hippocampus of these mice, the wave propagated as in control animals. In addition to calcium wave propagation in astrocytes, ATP-release was recorded as a calcium signal from 'sniffer cells', a cell line expressing high-affinity purinergic receptors placed on the surface of the slice. The astrocyte calcium wave in the neocortex was accompanied by calcium signals in the 'sniffer cell' population. In the connexin43-deficient mice we recorded calcium signals from sniffer cells also in the absence of an astrocytic calcium wave. Our findings indicate that astrocytes propagate calcium signals by two separate mechanisms depending on the brain region and that ATP release can propagate within the neocortex independent from calcium waves.

Parallel temperature dependence of contracture-associated enzyme release due to anoxia, 2,4-dinitrophenol (DNP), or caffeine and the calcium paradox.

PubMed Central

Ganote, C. E.; Sims, M. A.

1984-01-01

Hypothermia during calcium-free perfusion of hearts protects them from injury caused by subsequent calcium repletion at 37 C (calcium paradox). Injury to calcium-free hearts is also associated with contracture caused by anoxia, 2,4-dinitrophenol (DNP), or caffeine. This study was done for the purpose of determining whether hypothermia during calcium-free perfusions protects hearts from contracture-associated injury. Langendorff-perfused rat hearts were studied in four experimental groups: I) Anoxia: Thirty minutes of anoxic perfusion at 37 C was followed by thirty minutes of anoxic calcium-free perfusion at 37-18 C. II) Calcium paradox: Five minutes of calcium-free perfusion at 37-18 C was followed by calcium repletion at 37 C. III, IVa) Caffeine or DNP: Five minutes of calcium-free perfusion at 37-18 C was followed by addition of 10 mM caffeine or 1 mM DNP in calcium-free medium at 37 C or, IVb) 1 mM DNP in calcium-free medium at 22 C. Injury was assessed by measurement of serial releases of creatine kinase (CK) in effluents and by cellular morphology. The results show that progressive hypothermia to 22 C during calcium-free perfusion periods produced a progressive reduction of CK release and morphologic evidence of injury due to anoxia, caffeine, or DNP, which closely paralleled protection of hearts from the calcium paradox. Protection from injury in all experimental groups was associated with preservation of sarcolemmal membrane integrity and prevention of cell separations at intercalated disk junctions. It is proposed that weakening of intercalated disks occurs during calcium-free perfusions and may be a cause of mechanical fragility of the sarcolemma. Hypothermia may protect hearts from contracture-associated injury by preserving the integrity of intercalated disk junctions during periods of extracellular calcium depletion. Images Figure 4 Figure 5 Figure 6 Figure 7 Figure 8 Figure 9 Figure 10 Figure 11 PMID:6742111

Ionic calcium determination in skim milk with molecular probes and front-face fluorescence spectroscopy: simple linear regression.

PubMed

Gangidi, R R; Metzger, L E

2006-11-01

The purpose of this study was to determine if the ionic calcium content of skim milk could be determined using molecular probes and front-face fluorescence spectroscopy. Current methods for determining ionic calcium are not sensitive, overestimate ionic calcium, or require complex procedures. Molecular probes designed specifically for measuring ionic calcium could potentially be used to determine the ionic calcium content of skim milk. The goal of the current study was to develop foundation methods for future studies to determine ionic calcium directly in skim milk and other dairy products with molecular probes and fluorescence spectroscopy. In this study, the effect of pH on calcium-sensitive fluorescent probe (Rhod-5N and Fluo-5N) performance using various concentrations of skim milk was determined. The pH of diluted skim milk (1.9 to 8.9% skim milk), was adjusted to either 6.2 or 7.0, after which the samples were analyzed with fluorescent probes (1 microM) and front-face fluorescence spectroscopy. The ionic calcium content of each sample was also determined using a calcium ion-selective electrode. The results demonstrated that the ionic calcium content of each sample was highly correlated (R2 > 0.989) with the fluorescence intensities of the probe-calcium adduct using simple linear regression. Higher than suggested ionic calcium contents of 1,207 and 1,973 microM were determined with the probes (Fluo-5N and Rhod-5N) in diluted skim milk with pH 7.0 and 6.2, respectively. The fluorescence intensity of the probe-calcium adduct decreased with a decrease in pH for the same ionic calcium concentration. This study demonstrates that Fluo-5N and Rhod-5N can be used to determine the ionic-calcium content of diluted milk with front-face fluorescence spectroscopy. Furthermore, these probes may also have the potential to determine the ionic calcium content of undiluted skim milk.

Altered sarco(endo)plasmic reticulum calcium adenosine triphosphatase 2a content: Targets for heart failure therapy.

PubMed

Liu, Gang; Li, Si Qi; Hu, Ping Ping; Tong, Xiao Yong

2018-05-01

Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is responsible for transporting cytosolic calcium into the sarcoplasmic reticulum and endoplasmic reticulum to maintain calcium homeostasis. Sarco(endo)plasmic reticulum calcium adenosine triphosphatase is the dominant isoform expressed in cardiac tissue, which is regulated by endogenous protein inhibitors, post-translational modifications, hormones as well as microRNAs. Dysfunction of sarco(endo)plasmic reticulum calcium adenosine triphosphatase is associated with heart failure, which makes sarco(endo)plasmic reticulum calcium adenosine triphosphatase a promising target for heart failure therapy. This review summarizes current approaches to ameliorate sarco(endo)plasmic reticulum calcium adenosine triphosphatase function and focuses on phospholamban, an endogenous inhibitor of sarco(endo)plasmic reticulum calcium adenosine triphosphatase, pharmacological tools and gene therapies.

Characterization of sea cucumber (stichopus japonicus) ovum hydrolysates: calcium chelation, solubility and absorption into intestinal epithelial cells.

PubMed

Sun, Na; Cui, Pengbo; Lin, Songyi; Yu, Cuiping; Tang, Yue; Wei, Ye; Xiong, Youling; Wu, Haitao

2017-10-01

Sea cucumber (Stichopus japonicus) ovum hydrolysates (SCOHs) chelated with calcium were produced to investigate the characteristics of calcium binding and solubility, as well as to study any effects on calcium absorption by human intestinal epithelial cells. The results of the present study show that the calcium-binding capacity of SCOHs depended greatly on the type of proteases. The maximum level of Ca binding (0.38 mmol L -1 ) occurred when trypsin was used, with a peptide yield of 85.7%. Investigation of the possible chelating modes between SCOHs and calcium ions indicated that calcium ions bound to SCOHs primarily via interactions with carboxyl oxygen and amino nitrogen atoms of Glu and Asp and also that the phosphoserine residues might be also responsible for SCOH-calcium chelation. Moreover, SCOH-calcium complexes maintained the solubility of calcium under simulated gastrointestinal digestion, regardless of the presence of dietary components such as oxalate. Furthermore, SCOH-Ca led to higher peak intracellular [Ca 2+ ] i in both Caco-2 cells (338.3 nmol L -1 versus 269.6 nmol L -1 ) and HT-29 cells (373.9 nmol L -1 versus 271.7 nmol L -1 ) than casein phosphopeptide-Ca. Carboxyl oxygen and amino nitrogen atoms in the SCOHs could bind calcium ions, forming SCOH-calcium complexes. These complexes improved calcium solubility under simulated gastrointestinal digestion and also promoted calcium absorption in Caco-2 and HT-29 cells. © 2017 Society of Chemical Industry. © 2017 Society of Chemical Industry.

Studying dyadic structure-function relationships: a review of current modeling approaches and new insights into Ca2+ (mis)handling.

PubMed

Maleckar, Mary M; Edwards, Andrew G; Louch, William E; Lines, Glenn T

2017-01-01

Excitation-contraction coupling in cardiac myocytes requires calcium influx through L-type calcium channels in the sarcolemma, which gates calcium release through sarcoplasmic reticulum ryanodine receptors in a process known as calcium-induced calcium release, producing a myoplasmic calcium transient and enabling cardiomyocyte contraction. The spatio-temporal dynamics of calcium release, buffering, and reuptake into the sarcoplasmic reticulum play a central role in excitation-contraction coupling in both normal and diseased cardiac myocytes. However, further quantitative understanding of these cells' calcium machinery and the study of mechanisms that underlie both normal cardiac function and calcium-dependent etiologies in heart disease requires accurate knowledge of cardiac ultrastructure, protein distribution and subcellular function. As current imaging techniques are limited in spatial resolution, limiting insight into changes in calcium handling, computational models of excitation-contraction coupling have been increasingly employed to probe these structure-function relationships. This review will focus on the development of structural models of cardiac calcium dynamics at the subcellular level, orienting the reader broadly towards the development of models of subcellular calcium handling in cardiomyocytes. Specific focus will be given to progress in recent years in terms of multi-scale modeling employing resolved spatial models of subcellular calcium machinery. A review of the state-of-the-art will be followed by a review of emergent insights into calcium-dependent etiologies in heart disease and, finally, we will offer a perspective on future directions for related computational modeling and simulation efforts.

Effects of soaking and acidification on physicochemical properties of calcium-fortified rice.

PubMed

Sirisoontaralak, Porntip; Limboon, Pailin; Jatuwong, Sujitra; Chavanalikit, Arusa

2016-06-01

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.

Isolation and identification of calcium-chelating peptides from Pacific cod skin gelatin and their binding properties with calcium.

PubMed

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

2017-12-13

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.

Voltage-gated calcium flux mediates Escherichia coli mechanosensation.

PubMed

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

2017-08-29

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.

Voltage-gated calcium flux mediates Escherichia coli mechanosensation

PubMed Central

Weekley, R. Andrew; Dodd, Benjamin J. T.

2017-01-01

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. PMID:28808010

Aluminum hydroxide, calcium carbonate and calcium acetate in chronic intermittent hemodialysis patients.

PubMed

Janssen, M J; van der Kuy, A; ter Wee, P M; van Boven, W P

1996-02-01

Prevention of secondary hyperparathyroidism in uremia necessitates correction of hyperphosphatemia and hypocalcemia. In order to avoid aluminum toxicity, calcium containing phosphate binders are used increasingly, instead of aluminium hydroxide. Recent studies have shown that calcium acetate has many characteristics of an ideal phosphate binder. It is, for instance, a more readily soluble salt compared with calcium carbonate. This advantage might, however, disappear if calcium carbonate is taken on an empty stomach, a few minutes before meals. We examined the efficacy of three different phosphate binding agents in a randomized prospective study of 53 patients on regular hemodialysis. Bicarbonate dialyses were performed with a dialysate calcium concentration of 1.75 mmol/l. After a three-week wash-out period, patients received either aluminum hydroxide (control group), calcium acetate, or calcium carbonate as their phosphate binder. Patients were instructed to take the calcium salts a few minutes before meals on an empty stomach, and aluminum hydroxide during meals. Serum calcium, phosphate, intact parathormone, and alkaline phosphatase levels were determined every month. Patient compliance was estimated every month by asking the patients which phosphate binder and what daily dose they had used. Aluminum hydroxide tended to be the most effective phosphate binder. The mean +/- SEM required daily dose of calcium acetate at 12 months was 5.04 +/- 0.60 g, corresponding to 10.1 +/- 1.20 tablets of 500 mg. Co-medication with aluminum hydroxide, however, was needed (1.29 +/- 0.54 g per day, corresponding to 2.6 +/- 1.08 tablets of 500 mg). The required daily calcium carbonate dose appeared to be 2.71 +/- 0.48 g, corresponding to 5.4 +/- 0.95 capsules of 500 mg, with an adjuvant daily aluminum hydroxide dose of 0.69 +/- 0.27 g, corresponding to 1.4 +/- 0.55 tablets of 500 mg (p = 0.0055). Thus, the mean daily doses of elemental calcium were comparable between the calcium acetate and calcium carbonate-treated patients (1.28 +/- 0.15 g versus 1.09 +/- 0.19 g; n.s.). The incidence of hypercalcemic episodes (albumin-corrected serum calcium levels above 2.80 mmol/l) in the calcium acetate-treated group was 18% versus 31% in the calcium carbonate-treated group (p < 0.005). None of the aluminum hydroxide-treated patients experienced hypercalcemic episodes. Mean serum concentrations of alkaline phosphatase, intact parathormone, and aluminum did not differ between the groups. In chronic intermittent hemodialysis patients, per gram administered elemental calcium phosphate binding with either calcium acetate or calcium carbonate is equivalent, provided that calcium carbonate is taken on an empty stomach a few minutes before meals. The number of capsules calcium carbonate, but also the total amount in grams, necessary to keep serum phosphate and intact parathormone levels into an acceptable range then is significantly less. This might improve patient compliance.

Ultracytochemical visualization of calcium distribution in heart cells and erythrocytes of zebrafish Danio rerio.

PubMed

Niksirat, Hamid; Steinbach, Christoph

2018-05-24

Detection of patterns of subcellular calcium distribution in the cardiovascular system can contribute to understanding its role in cardiac and blood function. The present study localized calcium in heart atrium, ventricle, and bulbus arteriosus as well as in erythrocytes of zebrafish Danio rerio using an oxalate-pyroantimonate technique combined with transmission electron microscopy. Intracellular calcium stores were detected in caveolae, mitochondria, and the nuclei of several zebrafish cardiac cell types. Melanin pigmentation containing calcium stores was detected in the pericardial cavity. Melanin might be an extracellular source of calcium for heart beating and/or a lubricant to prevent friction during beating process. Calcium deposits were also detected in the plasma membrane, cytoplasm and nucleus of erythrocytes as well as in blood plasma. Possible exchange of calcium between erythrocytes and blood plasma was observed. Interactions of such calcium stores and possible contribution of extracellular calcium stores such as melanin pigmentation to supply calcium for vital functions of heart cells should be addressed in future studies. Copyright © 2018 Elsevier Ltd. All rights reserved.

Calcium Signaling in Taste Cells

PubMed Central

Medler, Kathryn F.

2014-01-01

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

21 CFR 184.1195 - Calcium citrate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Calcium citrate. 184.1195 Section 184.1195 Food... 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 calcium hydroxide or...

Calcium fertilization increases the concentration of calcium in sapwood and calcium oxalate in foliage of red spruce

Treesearch

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

2009-01-01

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...

Live Imaging of Calcium Dynamics during Axon Degeneration Reveals Two Functionally Distinct Phases of Calcium Influx

PubMed Central

Yamagishi, Yuya; Tessier-Lavigne, Marc

2015-01-01

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 pharmacological treatments in both zebrafish and cultured mouse sensory neurons revealed that axonal calcium influx late in the degeneration process regulates axon fragmentation. These findings suggest that temporal considerations will be crucial for developing treatments for diseases associated with axon degeneration. PMID:26558774

The probability of quantal secretion near a single calcium channel of an active zone.

PubMed Central

Bennett, M R; Farnell, L; Gibson, W G

2000-01-01

A Monte Carlo analysis has been made of calcium dynamics and quantal secretion at microdomains in which the calcium reaches very high concentrations over distances of <50 nm from a channel and for which calcium dynamics are dominated by diffusion. The kinetics of calcium ions in microdomains due to either the spontaneous or evoked opening of a calcium channel, both of which are stochastic events, are described in the presence of endogenous fixed and mobile buffers. Fluctuations in the number of calcium ions within 50 nm of a channel are considerable, with the standard deviation about half the mean. Within 10 nm of a channel these numbers of ions can give rise to calcium concentrations of the order of 100 microM. The temporal changes in free calcium and calcium bound to different affinity indicators in the volume of an entire varicosity or bouton following the opening of a single channel are also determined. A Monte Carlo analysis is also presented of how the dynamics of calcium ions at active zones, after the arrival of an action potential and the stochastic opening of a calcium channel, determine the probability of exocytosis from docked vesicles near the channel. The synaptic vesicles in active zones are found docked in a complex with their calcium-sensor associated proteins and a voltage-sensitive calcium channel, forming a secretory unit. The probability of quantal secretion from an isolated secretory unit has been determined for different distances of an open calcium channel from the calcium sensor within an individual unit: a threefold decrease in the probability of secretion of a quantum occurs with a doubling of the distance from 25 to 50 nm. The Monte Carlo analysis also shows that the probability of secretion of a quantum is most sensitive to the size of the single-channel current compared with its sensitivity to either the binding rates of the sites on the calcium-sensor protein or to the number of these sites that must bind a calcium ion to trigger exocytosis of a vesicle. PMID:10777721

Radiological study of the effect of low calcium diet on the mineral metabolism of bone tissue. With reference to mineralization in callus (in Japanese)

DOE Office of Scientific and Technical Information (OSTI.GOV)

Nakamura, K.

1972-01-01

Deficiency of available food material due either to poor diet or to malabsorption may adversely affect the skeleton. To study the affection, DDN mice were fed low calcium diet to induce low calcium state corresponding to malabsorption of calcium from the intestine. The femur was fractured manually. Then, calcium deposition in the callus was observed by microradiography and tracer technics with /sup 47/Ca. Increase of the body weight in mice fed low calcium diet was much slower than in the control. The affection of the low calcium diet on bone tissue appeared as a decrease of precipitation of calcium salt.more » This tendency was also observed in callus, Tracer study with /sup 47/Ca was performed in mice fed the low calcium diet for 24 days. Incorporation activity of calcium was generally high in each organ except the kidney. Callus in the site of the fracture in mice fed a low calcium diet was formed to the same degree as the control, although the amount of precipitated calcium in it was significantly poorer. In summary, insufficient mineralization in relation to osteogenesis occurred when the supply of the requisite electrolytes was insufficient or inappropriate. On the other hand, the uptake rate of calcinm in the callus was elevated even in the calcium deficient state. (auth)« less

Depletion of intracellular calcium stores facilitates the influx of extracellular calcium in platelet derived growth factor stimulated A172 glioblastoma cells.

PubMed

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

1996-05-01

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.

Molten salt applications in materials processing

NASA Astrophysics Data System (ADS)

Mishra, Brajendra; Olson, David L.

2005-02-01

The science of molten salt electrochemistry for electrowinning of reactive metals, such as calcium, and its in situ application in pyro-reduction has been described. Calcium electrowinning has been performed in a 5 10 wt% calcium oxide calcium chloride molten salt by the electrolytic dissociation of calcium oxide. This electrolysis requires the use of a porous ceramic sheath around the anode to keep the cathodically deposited calcium and the anodic gases separate. Stainless steel cathode and graphite anode have been used in the temperature range of 850 950 °C. This salt mixture is produced as a result of the direct oxide reduction (DOR) of reactive metal oxides by calcium in a calcium chloride bath. The primary purpose of this process is to recover the expensive calcium reductant and to recycle calcium chloride. Experimental data have been included to justify the suitability as well as limitations of the electrowinning process. Transport of oxygen ions through the sheath is found to be the rate controlling step. Under the constraints of the reactor design, a calcium recovery rate of approx. 150 g/h was achieved. Feasibility of a process to produce metals by pyrometallurgical reduction, using the calcium reductant produced electrolytically within the same reactor, has been shown in a hybrid process. Several processes are currently under investigation to use this electrowon calcium for in situ reduction of metal oxides.

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

PubMed Central

Sharma, Divya; Jamra, Gautam; Singh, Uma M.; Sood, Salej; Kumar, Anil

2017-01-01

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 (Ca2+) 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 (Ca2+) accumulation in its grains and could pave way for development of nutraceuticals or designer crops. PMID:28144246

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.

PubMed

Sharma, Divya; Jamra, Gautam; Singh, Uma M; Sood, Salej; Kumar, Anil

2016-01-01

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.

21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 3 2010-04-01 2009-04-01 true Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 3 2011-04-01 2011-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 3 2014-04-01 2014-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... (CONTINUED) SUBSTANCES GENERALLY RECOGNIZED AS SAFE Anticaking Agents § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate...

21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 3 2013-04-01 2013-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 182.2729 - Sodium calcium aluminosilicate, hydrated.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 3 2012-04-01 2012-04-01 false Sodium calcium aluminosilicate, hydrated. 182.2729... § 182.2729 Sodium calcium aluminosilicate, hydrated. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

Space Flight Calcium: Implications for Astronaut Health, Spacecraft Operations, and Earth

PubMed Central

Smith, Scott M.; McCoy, Torin; Gazda, Daniel; Morgan, Jennifer L. L.; Heer, Martina; Zwart, Sara R.

2012-01-01

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. PMID:23250146

Circadian oscillations of cytosolic and chloroplastic free calcium in plants

NASA Technical Reports Server (NTRS)

Johnson, C. H.; Knight, M. R.; Kondo, T.; Masson, P.; Sedbrook, J.; Haley, A.; Trewavas, A.

1995-01-01

Tobacco and Arabidopsis plants, expressing a transgene for the calcium-sensitive luminescent protein apoaequorin, revealed circadian oscillations in free cytosolic calcium that can be phase-shifted by light-dark signals. When apoaequorin was targeted to the chloroplast, circadian chloroplast calcium rhythms were likewise observed after transfer of the seedlings to constant darkness. Circadian oscillations in free calcium concentrations can be expected to control many calcium-dependent enzymes and processes accounting for circadian outputs. Regulation of calcium flux is therefore fundamental to the organization of circadian systems.

Space flight calcium: implications for astronaut health, spacecraft operations, and Earth.

PubMed

Smith, Scott M; McCoy, Torin; Gazda, Daniel; Morgan, Jennifer L L; Heer, Martina; Zwart, Sara R

2012-12-18

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.

Acoustic and Hydrodynamic Cavitations for Nano CaCO3 Synthesis

NASA Astrophysics Data System (ADS)

Sonawane, Shirish H.; Kulkarni, Ravindra D.

Calcium carbonate is a common inorganic compound known as limestone. Calcium carbonate has many applications in industries such as medicine, agriculture, paint plastic and surface coatings etc. The vast majority of calcium carbonate used in industry is extracted by mining process. Pure calcium carbonate (e.g. for food or pharmaceutical use), is synthesized by passing carbon dioxide into a solution of calcium hydroxide slurry. In this process calcium carbonate precipitates out, and this grade of product is referred to as precipitate calcium carbonate (abbreviated as PCC).

Egg Shell and Oyster Shell Powder as Alternatives for Synthetic Phosphate: Effects on the Quality of Cooked Ground Pork Products

PubMed Central

2017-01-01

This study aimed to determine the optimal ratio of natural calcium powders (oyster shell and egg shell calcium) as synthetic phosphate replacers in pork products. Ground pork samples were subjected to six treatments, as follows: control (−) (no phosphate added), control (+) (0.3% phosphate blend added), treatment 1 (0.5% oyster shell calcium powder added), treatment 2 (0.3% oyster shell calcium powder and 0.2% egg shell calcium powder added), treatment 3 (0.2% oyster shell calcium powder and 0.3% egg shell calcium powder added), and treatment 4 (0.5% egg shell calcium powder added). The addition of natural calcium powders resulted in an increase in the pH values of meat products, regardless of whether they were used individually or mixed. The highest cooking loss was observed (p<0.05) in the negative control samples, whereas the cooking loss in samples with natural calcium powder added was similar (p>0.05) to that in the positive control samples. CIE L* values decreased as the amount of added egg shell calcium powder increased. CIE a* values were higher (p<0.05) in samples containing natural calcium powder (treatments 1, 2, 3, and 4) than in the positive control. The combination of oyster shell calcium powder and egg shell powder (treatment 2 or 3) was effective for the improvement of textural properties of the pork products. The findings show that the combined use of 0.2% oyster shell calcium and 0.3% egg shell calcium should enable the replacement of synthetic phosphate in the production of cooked pork products with desirable qualities. PMID:28943770

Trends in calcium supplementation, National Health and Nutrition Examination Survey (NHANES) 1999-2014.

PubMed

Rooney, Mary R; Michos, Erin D; Hootman, Katie C; Harnack, Lisa; Lutsey, Pamela L

2018-06-01

Long-term outcomes of supplemental calcium are inadequately understood. Recent research suggests that calcium from supplements may not be entirely free from unintended health consequences. Consequently, it is important to understand patterns and trends in use of calcium supplements. To report trends in supplemental calcium intake between 1999 and 2014, using NHANES data, overall and stratified by sex, race/ethnicity and age. A total of 42,038 adult NHANES participants were included in this analysis. For each survey period, we calculated the prevalence of calcium supplement use exceeding the Estimated Average Requirement (EAR) and Tolerable Upper Intake Levels (UL), and mean daily supplemental calcium dose among calcium-containing supplement users. Sample weights were applied. Linear regression was used to examine trends. Overall, the prevalence of calcium supplement use at a dose ≥EAR increased between 1999 and 2000 and 2013-2014, from 2.5% (95% CI: 1.9-3.3%) to 4.6% (3.8-5.5%). Use ≥EAR peaked in 2003-2004 at 6.7% (5.3-8.5%) (p-quadratic trend<0.001). Mean supplemental calcium intake peaked in 2007-2008, thereafter decreasing (p-quadratic trend<0.001). The overall prevalence of intake ≥UL from supplemental calcium in 2013-2014 was 0.4% (0.2-0.8%). Use of supplemental calcium ≥UL peaked during 2007-2008 at 1.2% (0.7-2.0%). In all time periods, supplemental calcium intake tended to be greater among women, non-Hispanic whites and adults >60years. We described the prevalence of U.S. adults consuming supplemental calcium ≥UL and ≥ EAR. While few were consuming supplemental calcium ≥UL, consumption ≥EAR was not uncommon, especially among women, non-Hispanic whites and older adults. Copyright © 2018 Elsevier Inc. All rights reserved.

Calcium signaling properties of a thyrotroph cell line, mouse TαT1 cells.

PubMed

Tomić, Melanija; Bargi-Souza, Paula; Leiva-Salcedo, Elias; Nunes, Maria Tereza; Stojilkovic, Stanko S

2015-12-01

TαT1 cells are mouse thyrotroph cell line frequently used for studies on thyroid-stimulating hormone beta subunit gene expression and other cellular functions. Here we have characterized calcium-signaling pathways in TαT1 cells, an issue not previously addressed in these cells and incompletely described in native thyrotrophs. TαT1 cells are excitable and fire action potentials spontaneously and in response to application of thyrotropin-releasing hormone (TRH), the native hypothalamic agonist for thyrotrophs. Spontaneous electrical activity is coupled to small amplitude fluctuations in intracellular calcium, whereas TRH stimulates both calcium mobilization from intracellular pools and calcium influx. Non-receptor-mediated depletion of intracellular pool also leads to a prominent facilitation of calcium influx. Both receptor and non-receptor stimulated calcium influx is substantially attenuated but not completely abolished by inhibition of voltage-gated calcium channels, suggesting that depletion of intracellular calcium pool in these cells provides a signal for both voltage-independent and -dependent calcium influx, the latter by facilitating the pacemaking activity. These cells also express purinergic P2Y1 receptors and their activation by extracellular ATP mimics TRH action on calcium mobilization and influx. The thyroid hormone triiodothyronine prolongs duration of TRH-induced calcium spikes during 30-min exposure. These data indicate that TαT1 cells are capable of responding to natively feed-forward TRH signaling and intrapituitary ATP signaling with acute calcium mobilization and sustained calcium influx. Amplification of TRH-induced calcium signaling by triiodothyronine further suggests the existence of a pathway for positive feedback effects of thyroid hormones probably in a non-genomic manner. Published by Elsevier Ltd.

Protein kinases as mediators of fluid shear stress stimulated signal transduction in endothelial cells: a hypothesis for calcium-dependent and calcium-independent events activated by flow.

PubMed

Berk, B C; Corson, M A; Peterson, T E; Tseng, H

1995-12-01

Fluid shear stress regulates endothelial cell function, but the signal transduction mechanisms involved in mechanotransduction remain unclear. Recent findings demonstrate that several intracellular kinases are activated by mechanical forces. In particular, members of the mitogen-activated protein (MAP) kinase family are stimulated by hyperosmolarity, stretch, and stress such as heat shock. We propose a model for mechanotransduction in endothelial cells involving calcium-dependent and calcium-independent protein kinase pathways. The calcium-dependent pathway involves activation of phospholipase C, hydrolysis of phosphatidylinositol 4,5-bisphosphate (PIP2), increases in intracellular calcium and stimulation of kinases such as calcium-calmodulin and C kinases (PKC). The calcium-independent pathway involves activation of a small GTP-binding protein and stimulation of calcium-independent PKC and MAP kinases. The calcium-dependent pathway mediates the rapid, transient response to fluid shear stress including activation of nitric oxide synthase (NOS) and ion transport. In contrast, the calcium-independent pathway mediates a slower response including the sustained activation of NOS and changes in cell morphology and gene expression. We propose that focal adhesion complexes link the calcium-dependent and calcium-independent pathways by regulating activity of phosphatidylinositol 4-phosphate (PIP) 5-kinase (which regulates PIP2 levels) and p125 focal adhesion kinase (FAK, which phosphorylates paxillin and interacts with cytoskeletal proteins). This model predicts that dynamic interactions between integrin molecules present in focal adhesion complexes and membrane events involved in mechanotransduction will be integrated by calcium-dependent and calcium-independent kinases to generate intracellular signals involved in the endothelial cell response to flow.

Intestinal absorption and renal reabsorption of calcium throughout postnatal development

PubMed Central

Beggs, Megan R

2017-01-01

Calcium is vital for many physiological functions including bone mineralization. Postnatal deposition of calcium into bone is greatest in infancy and continues through childhood and adolescence until peek mineral density is reached in early adulthood. Thereafter, bone mineral density remains static until it eventually declines in later life. A positive calcium balance, i.e. more calcium absorbed than excreted, is crucial to bone deposition during growth and thus to peek bone mineral density. Dietary calcium is absorbed from the intestine into the blood. It is then filtered by the renal glomerulus and either reabsorbed by the tubule or excreted in the urine. Calcium can be (re)absorbed across intestinal and renal epithelia via both transcellular and paracellular pathways. Current evidence suggests that significant intestinal and renal calcium transport changes occur throughout development. However, the molecular details of these alterations are incompletely delineated. Here we first briefly review the current model of calcium transport in the intestine and renal tubule in the adult. Then, we describe what is known with regard to calcium handling through postnatal development, and how alterations may aid in mediating a positive calcium balance. The role of transcellular and paracellular calcium transport pathways and the contribution of specific intestinal and tubular segments vary with age. However, the current literature highlights knowledge gaps in how specifically intestinal and renal calcium (re)absorption occurs early in postnatal development. Future research should clarify the specific changes in calcium transport throughout early postnatal development including mediators of these alterations enabling appropriate bone mineralization. Impact statement This mini review outlines the current state of knowledge pertaining to the molecules and mechanisms maintaining a positive calcium balance throughout postnatal development. This process is essential to achieving optimal bone mineral density in early adulthood, thereby lowering the lifetime risk of osteoporosis. PMID:28346014

Egg Shell and Oyster Shell Powder as Alternatives for Synthetic Phosphate: Effects on the Quality of Cooked Ground Pork Products.

PubMed

Cho, Min Guk; Bae, Su Min; Jeong, Jong Youn

2017-01-01

This study aimed to determine the optimal ratio of natural calcium powders (oyster shell and egg shell calcium) as synthetic phosphate replacers in pork products. Ground pork samples were subjected to six treatments, as follows: control (-) (no phosphate added), control (+) (0.3% phosphate blend added), treatment 1 (0.5% oyster shell calcium powder added), treatment 2 (0.3% oyster shell calcium powder and 0.2% egg shell calcium powder added), treatment 3 (0.2% oyster shell calcium powder and 0.3% egg shell calcium powder added), and treatment 4 (0.5% egg shell calcium powder added). The addition of natural calcium powders resulted in an increase in the pH values of meat products, regardless of whether they were used individually or mixed. The highest cooking loss was observed ( p <0.05) in the negative control samples, whereas the cooking loss in samples with natural calcium powder added was similar ( p >0.05) to that in the positive control samples. CIE L* values decreased as the amount of added egg shell calcium powder increased. CIE a* values were higher ( p <0.05) in samples containing natural calcium powder (treatments 1, 2, 3, and 4) than in the positive control. The combination of oyster shell calcium powder and egg shell powder (treatment 2 or 3) was effective for the improvement of textural properties of the pork products. The findings show that the combined use of 0.2% oyster shell calcium and 0.3% egg shell calcium should enable the replacement of synthetic phosphate in the production of cooked pork products with desirable qualities.

The Function of the Mitochondrial Calcium Uniporter in Neurodegenerative Disorders

PubMed Central

Liao, Yajin; Dong, Yuan; Cheng, Jinbo

2017-01-01

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. PMID:28208618

Surface area dependence of calcium isotopic reequilibration in carbonates: Implications for isotopic signatures in the weathering zone

NASA Astrophysics Data System (ADS)

Fernandez, N. M.; Druhan, J. L.; Potrel, A.; Jacobson, A. D.

2016-12-01

The concept of dynamic equilibrium carries the implicit assumption of continued isotopic exchange between a mineral and the surrounding fluid. While this effect has received much attention in the marine paleoproxy literature, it has been relatively overlooked in application to the terrestrial environment. In weathering systems, a potential consequence is that rapid reequilibration may alter or erase isotopic signatures generated during secondary mineral formation. The extent and timescale over which isotopic signatures are reset in these hydrologic systems is unknown. Using reactive transport modeling, we show isotopic reequilibration under conditions reflecting terrestrial hydrologic settings to be significant and dependent on the reactive surface area of the solid. In particular, we suggest that the non-traditional stable isotopes commonly used in application to carbonates (e.g., Ca, Mg, Sr) are sensitive to these effects due to their rapid reaction rates. We aim to characterize the dependence of Ca isotopic reequilibration on surface area during calcite precipitation via batch experiments conducted at ambient temperature over 48-hour time periods. Calcite precipitation was performed in a closed batch reactor utilizing a controlled free-drift method. The batch reactors contained mixed supersaturated solutions of CaCl2 and NaHCO3 at an initial pH of 8.54. Precipitation was initiated by seed inoculation of calcite crystals with two distinct, pre-constrained surface areas. All experiments achieved the same final state of chemical equilibrium, but as expected, the fastest approach to equilibrium occurred for experiments employing calcite seeds with the highest surface area. This implies that differences in equilibrated Ca isotope ratios (δ44/40Ca) should reflect differences in surface area. This prediction is upheld by models of the experiments, indicating a measureable difference in δ44Ca during calcite precipitation where the higher surface area corresponds to lower δ44Ca values and a faster approach to isotopic equilibrium. The dependence of δ44Ca resetting on calcite surface areas has broad ramifications for tracing carbonate weathering in the Critical Zone.

Calcium Isotope Analysis with "Peak Cut" Method on Column Chemistry

NASA Astrophysics Data System (ADS)

Zhu, H.; Zhang, Z.; Liu, F.; Li, X.

2017-12-01

To eliminate isobaric interferences from elemental and molecular isobars (e.g., 40K+, 48Ti+, 88Sr2+, 24Mg16O+, 27Al16O+) on Ca isotopes during mass determination, samples should be purified through ion-exchange column chemistry before analysis. However, large Ca isotopic fractionation has been observed during column chemistry (Russell and Papanastassiou, 1978; Zhu et al., 2016). Therefore, full recovery during column chemistry is greatly needed, otherwise uncertainties would be caused by poor recovery (Zhu et al., 2016). Generally, matrix effects could be enhanced by full recovery, as other elements might overlap with Ca cut during column chemistry. Matrix effects and full recovery are difficult to balance and both need to be considered for high-precision analysis of stable Ca isotopes. Here, we investigate the influence of poor recovery on δ44/40Ca using TIMS with the double spike technique. The δ44/40Ca values of IAPSO seawater, ML3B-G and BHVO-2 in different Ca subcats (e.g., 0-20, 20-40, 40-60, 60-80, 80-100%) with 20% Ca recovery on column chemistry display limited variation after correction by the 42Ca-43Ca double spike technique with the exponential law. Notably, δ44/40Ca of each Ca subcut is quite consistent with δ44/40Ca of Ca cut with full recovery within error. Our results indicate that the 42Ca-43Ca double spike technique can simultaneously correct both of the Ca isotopic fractionation that occurred during column chemistry and thermal ionization mass spectrometry (TIMS) determination properly, because both of the isotopic fractionation occurred during analysis follow the exponential law well. Therefore, we propose the "peak cut" method on Ca column chemistry for samples with complex matrix effects. Briefly, for samples with low Ca contents, we can add the double spike before column chemistry, and only collect the middle of the Ca eluate and abandon the both sides of Ca eluate that might overlap with other elements (e.g., K, Sr). This method would eliminate matrix effects and improve efficiency for the column chemistry.

21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

Code of Federal Regulations, 2010 CFR

2010-04-01

... 21 Food and Drugs 6 2010-04-01 2010-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

Code of Federal Regulations, 2011 CFR

2011-04-01

... 21 Food and Drugs 6 2011-04-01 2011-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

Code of Federal Regulations, 2012 CFR

2012-04-01

... 21 Food and Drugs 6 2012-04-01 2012-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

Code of Federal Regulations, 2014 CFR

2014-04-01

... 21 Food and Drugs 6 2014-04-01 2014-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

21 CFR 582.2729 - Hydrated sodium calcium aluminosilicate.

Code of Federal Regulations, 2013 CFR

2013-04-01

... 21 Food and Drugs 6 2013-04-01 2013-04-01 false Hydrated sodium calcium aluminosilicate. 582.2729... Agents § 582.2729 Hydrated sodium calcium aluminosilicate. (a) Product. Hydrated sodium calcium aluminosilicate (sodium calcium silicoaluminate). (b) Tolerance. This substance is generally recognized as safe...

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

PubMed

Madani, Babak; Mirshekari, Amin; Yahia, Elhadi

2016-07-01

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.

A Double-Blind Randomized Placebo Controlled Trial of Magnesium Oxide for Alleviation of Chronic Low Back Pain

DTIC Science & Technology

1999-01-01

minireview of the interactions between calcium channel blockers and analgesics. In a metaanalysis of several studies, they concluded that calcium ...Philadelphia: W. B. Saunders Company. Miranda, H., & Paeile, C. (1990). Interactions between analgesics and calcium channel blockers. General... calcium access into the cell and the actions of calcium inside the cell. The influx of calcium inside the depolarized presynaptic cell allows for

Direct Inhibitory Effect of Hypercalcemia on Renal Actions of Parathyroid Hormone

PubMed Central

Beck, Nama; Singh, Harbans; Reed, Sarah W.; Davis, Bernard B.

1974-01-01

The effects of calcium on the renal actions of parathyroid hormone (PTH) were studied in vivo and in vitro. In parathyroidectomized rats, variable levels of blood calcium concentration were induced by intravenous infusion of calcium. The renal responses to the injected PTH, i.e. phosphate and cyclic AMP excretion, were compared in these animals. After PTH injection, the increases of both phosphate and cyclic AMP excretion were less in the calcium-infused animals than in the control group without calcium infusion. There was an inverse correlation between the renal responses to PTH and plasma calcium concentration of 4.2-13.5 mg/100 ml. But calcium had no effect on phosphate excretion induced by infusion of dibutyryl cyclic AMP. In the in vitro experiments, the increase of cyclic AMP concentration in response to PTH was less in renal cortical slices taken from the calcium-infused animals than in ones from the control group without calcium infusion. Calcium also inhibited the activation of renal cortical adenylate cyclase in response to PTH, but calcium had no effect on phosphodiesterase. The data indicate that calcium directly inhibits renal actions of PTH both in vivo and in vitro. Such inhibitory mechanism is probably at or before the step of PTH-dependent cyclic AMP generation in the kidney. PMID:4359938

Selective dopamine receptor 4 activation mediates the hippocampal neuronal calcium response via IP3 and ryanodine receptors.

PubMed

Wang, Ya-Li; Wang, Jian-Gang; Guo, Fang-Li; Gao, Xia-Huan; Zhao, Dan-Dan; Zhang, Lin; Wang, Jian-Zhi; Lu, Cheng-Biao

2017-09-01

Intracellular calcium is a key factor in most cellular processes, including cell growth, differentiation, proliferation and neurotransmitter release. Dopamine (DA) mediates synaptic transmission by regulating the intracellular calcium content. It is not clear, however, which specific subunit of the DA receptor contributes to DA modulation of intracellular calcium content changes. Through the traditional technique of Fura-2 calcium imaging, this study demonstrated that the DA can induce transient calcium in cultured hippocampal neurons and that this response can be mimicked by a selective dopamine receptor 4 (DR4) agonist PD168077 (PD). PD-induced calcium transience can be blocked by a calcium chelator, such as BAPTA-AM, or by pre-treatment of neurons with thapsigargin, a IP 3 receptor antagonist, or a micromolar concentration of ryanodine, a ryanodine receptor (RyR) antagonist. However PD-induced calcium transience cannot be blocked by pre-treatment of neurons with a free-calcium medium or a cocktail of NMDA receptor, L-type calcium channel and alpha7 nicotinic acetylcholine receptor blockers. These results indicate that the calcium response induced by DR4 activation is mainly through activation of IP 3 receptor in internal stores, which is likely to contribute to the DA modulation of synaptic transmission and cognitive function. Copyright © 2017. Published by Elsevier B.V.