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1

Ascorbic acid prevents ?-amyloid-induced intracellular calcium increase and cell death in PC12 cells  

Microsoft Academic Search

Characteristics of Alzheimer's disease include loss of brain neurons associated with the deposit of beta-amyloid protein (A?) which is thought to be toxic to neurons possibly via induction of intracellular calcium and generation of free radicals. On this basis, we have determined the effect of ascorbic acid on the cell death and calcium increase induced by A? in PC12 cells.

Sasidhar Yallampalli; Maria-Adelaide Micci; Giulio Taglialatela

1998-01-01

2

Klotho Prevents Renal Calcium Loss  

PubMed Central

Disturbed calcium (Ca2+) homeostasis, which is implicit to the aging phenotype of klotho-deficient mice, has been attributed to altered vitamin D metabolism, but alternative possibilities exist. We hypothesized that failed tubular Ca2+ absorption is primary, which causes increased urinary Ca2+ excretion, leading to elevated 1,25-dihydroxyvitamin D3 [1,25(OH)2D3] and its sequelae. Here, we assessed intestinal Ca2+ absorption, bone densitometry, renal Ca2+ excretion, and renal morphology via energy-dispersive x-ray microanalysis in wild-type and klotho?/? mice. We observed elevated serum Ca2+ and fractional excretion of Ca2+ (FECa) in klotho?/? mice. Klotho?/? mice also showed intestinal Ca2+ hyperabsorption, osteopenia, and renal precipitation of calcium-phosphate. Duodenal mRNA levels of transient receptor potential vanilloid 6 (TRPV6) and calbindin-D9K increased. In the kidney, klotho?/? mice exhibited increased expression of TRPV5 and decreased expression of the sodium/calcium exchanger (NCX1) and calbindin-D28K, implying a failure to absorb Ca2+ through the distal convoluted tubule/connecting tubule (DCT/CNT) via TRPV5. Gene and protein expression of the vitamin D receptor (VDR), 25-hydroxyvitamin D-1-?-hydroxylase (1?OHase), and calbindin-D9K excluded renal vitamin D resistance. By modulating the diet, we showed that the renal Ca2+ wasting was not secondary to hypercalcemia and/or hypervitaminosis D. In summary, these findings illustrate a primary defect in tubular Ca2+ handling that contributes to the precipitation of calcium-phosphate in DCT/CNT. This highlights the importance of klotho to the prevention of renal Ca2+ loss, secondary hypervitaminosis D, osteopenia, and nephrocalcinosis.

Alexander, R. Todd; Woudenberg-Vrenken, Titia E.; Buurman, Jan; Dijkman, Henry; van der Eerden, Bram C. J.; van Leeuwen, Johannes P.T.M.; Bindels, Rene J.

2009-01-01

3

Association between inhibition of arachidonic acid release and prevention of calcium loading during ATP depletion in cultured rat cardiac myocytes  

SciTech Connect

The development of irreversible myocardial ischemic injury is associated with progressive degradation of membrane phospholipids, accumulation of arachidonate and other free fatty acids, and electrolyte derangements, including calcium accumulation. To study the relationship between arachidonate release and calcium loading during adenosine triphosphate (ATP) depletion in cardiac myocytes, the effects of two purported phospholipase inhibitors, mepacrine and U26,384, were evaluated. Cultured neonatal rat ventricular myocytes were pretreated for 90 minutes with 5 to 10 microM U26,384 (a steroidal diamine) or 10 to 50 microM mepacrine (an alkyl acridine) and then treated for 3 hours with 30 microM of the metabolic inhibitor, iodoacetic acid (IAA), with or without an additional dose of drug. IAA treatment resulted in a marked reduction in ATP level and a several-fold increase in free fatty acid radioactivity released from myocytes prelabeled with tritiated arachidonic acid (3H-AA). U26,384 produced substantial inhibition of the increased 3H-AA release, and was effective when given as a single pretreatment dose before IAA exposure or as continuous treatment before and during IAA exposure (for example, with 5 microM U26,384, the percentage of 3H-AA release versus IAA alone was 8% +/- 2% (SEM) (N = 15) for pretreatment only and 13% +/- 4% (N = 10) for continuous treatment). Mepacrine also resulted in significant reduction in 3H-AA release, but was more effective when given as continuous treatment (for example, with 50 microM mepacrine, the percentage of 3H-AA release versus IAA alone was 43% +/- 9% (N = 6) for pretreatment only and 22% +/- 7% (N = 9) for continuous treatment). More detailed analysis showed that U26,384 and mepacrine blocked the IAA-induced redistribution of 3H-AA into free fatty acids from other lipid species.

Jones, R.L.; Miller, J.C.; Hagler, H.K.; Chien, K.R.; Willerson, J.T.; Buja, L.M. (Univ. of Texas, Dallas (USA))

1989-09-01

4

The Effects of Diet Calcium, Protein and Acidity on Calcium Retention in the Rat, Particularly as Related to the Inner and Outer Surfaces of Tubular Bone: A Possible Model for the Treatment or Prevention of Osteoporosis.  

National Technical Information Service (NTIS)

The effects of graded levels of diet calcium, protein and acidity on radiographic and gravimetric measurements, and on mineral composition of femurs were studied in Long Evans, young and old, female rats. With increased diet calcium, femur potassium perce...

J. E. Milligan

1979-01-01

5

Vinylphosphonic acid-modified calcium aluminate and calcium silicate cements  

Microsoft Academic Search

Cementitious materials in terms of calcium phosphate cements (CPC) were prepared through the acid-base reaction between vinylphosphonic acid (VPA) and calcium aluminate cement (CAC) reactants or calcium silicate cement (CSC) reactants at 25 °C. Using CAC, two factors were responsible for the development of strength in the cements: one is the formation of an amorphous calcium-complexed vinylphosphonate (CCVP) salt phase

T. Sugama; R. N. Mora

1996-01-01

6

Vitamin D and Calcium Supplementation to Prevent Fractures  

MedlinePLUS

... 1 Understanding Task Force Recommendations Vitamin D and Calcium Supplementation to Prevent Fractures The U.S. Preventive Services ... are vitamin D and calcium? Vitamin D and calcium are important nutrients that work together to keep ...

7

Abscisic acid triggers whole-plant and fruit-specific mechanisms to increase fruit calcium uptake and prevent blossom end rot development in tomato fruit.  

PubMed

Calcium (Ca) uptake into fruit and leaves is dependent on xylemic water movement, and hence presumably driven by transpiration and growth. High leaf transpiration is thought to restrict Ca movement to low-transpiring tomato fruit, which may increase fruit susceptibility to the Ca-deficiency disorder, blossom end rot (BER). The objective of this study was to analyse the effect of reduced leaf transpiration in abscisic acid (ABA)-treated plants on fruit and leaf Ca uptake and BER development. Tomato cultivars Ace 55 (Vf) and AB2 were grown in a greenhouse environment under Ca-deficit conditions and plants were treated weekly after pollination with water (control) or 500 mg l(-1) ABA. BER incidence was completely prevented in the ABA-treated plants and reached values of 30-45% in the water-treated controls. ABA-treated plants had higher stem water potential, lower leaf stomatal conductance, and lower whole-plant water loss than water-treated plants. ABA treatment increased total tissue and apoplastic water-soluble Ca concentrations in the fruit, and decreased Ca concentrations in leaves. In ABA-treated plants, fruit had a higher number of Safranin-O-stained xylem vessels at early stages of growth and development. ABA treatment reduced the phloem/xylem ratio of fruit sap uptake. The results indicate that ABA prevents BER development by increasing fruit Ca uptake, possibly by a combination of whole-plant and fruit-specific mechanisms. PMID:21282326

de Freitas, Sergio Tonetto; Shackel, Kenneth A; Mitcham, Elizabeth J

2011-01-31

8

Calcium and Cancer Prevention: Strengths and Limits of the Evidence  

Cancer.gov

A fact sheet that summarizes the results of studies on calcium and cancer prevention. It includes information about dietary recommendations for calcium, and the amount of calcium in foods and supplements.

9

The Role of Calcium in Prevention and Treatment of Osteoporosis.  

ERIC Educational Resources Information Center

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)

Heaney, Robert P.

1987-01-01

10

The Role of Calcium in Prevention and Treatment of Osteoporosis.  

ERIC Educational Resources Information Center

|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)|

Heaney, Robert P.

1987-01-01

11

Calcium apatite prepared from calcium hydroxide and orthophosphoric acid  

Microsoft Academic Search

Calcium hydroxyapatite has been prepared due to a direct precipitation reaction between 0.3m orthophosphoric acid solution and 0.1 mol calcium hydroxide dispersed in 200 ml water. The effect of the addition rate of the acid solution, reaction temperature and mixing molar Ca\\/P ratio is examined on the thermal stability and stoichiometry of the precipitates. Optimum conditions for HAp suitable for

A. Osaka; Y. Miura; K. Takeuchi; M. Asada; K. Takahashi

1991-01-01

12

Calcium, carbonic anhydrase and gastric acid secretion.  

PubMed

Previous data concerning the action of calcium (Ca) on gastric acid secretion (GAS) indicated that calcium ions increase GAS elicited by gastrin released through a vagal mechanism, and also by a direct effect on parietal cells. Our research showed that the stimulating effect of calcium on gastric acid secretion can be antagonized by verapamil administration, which reduces gastric acid secretion . In the present study we followed the effect induced by administration of calcium and Ca-chelating agents (disodium EDTA) on gastric acid secretion and on carbonic anhydrase (CA) activity. We selected two groups of healthy volunteers: Group I (n=21) received a single i.v. dose of CaCl2 (15 mg/kg b.w.), whereas Group II (n=22) received a single i.v. dose of disodium EDTA (5 mg/kg b.w.). We determined blood calcium before and after treatment, gastric acid secretion at 2 hours. erythrocyte CA II activity, and CA IV activity in membrane parietal cells, which were isolated from gastric mucosa obtained by endoscopic biopsy. Assessment of carbonic anhydrase activity was achieved by the stopped-flow method. In Group I calcium administration increased blood calcium, HCl output, CA II and CA IV activity as compared to initial values. In Group II, disodium EDTA reduced blood calcium, HCl output, CA II and CA IV activity as compared to initial values. The results demonstrated that increased blood calcium and GAS values after calcium administration correlated with the increase of erythrocyte CA II and parietal cell CA IV activity, while disodium EDTA induced a reversed process. Our results also show that cytosolic CA II and membrane CA IV values are sensitive to calcium changes and they directly depend on these levels. Our data suggest that intra- and extracellular pH changes induced by carbonic anhydrase might account for the modulation of the physiological and pathological secretory processes in the organism. PMID:11551141

Puscas, I; Coltau, M; Baican, M; Domuta, G; Hecht, A

2001-01-01

13

Calcium aluminosilicate glass corrosion by phosphoric acid  

Microsoft Academic Search

The corrosion rates of a series of calcium aluminosilicate and sodium calcium aluminosilicate glasses were determined in three phosphoric acids at several temperatures. The effect of temperature on corrosion rate was determined for one glass in 30 wt % HâPOâ; an activation energy was determined as well. The glasses are virtually insoluble at silica concentrations of >55 wt % SiOâ

N. C. Thakore; T. J. Rockett

1980-01-01

14

Use of High Calcium Infant Formula to Prevent Plumbism.  

National Technical Information Service (NTIS)

This study explored an alternative form of primary prevention of lead poisoning in children using the nutritional supplement calcium glycerophosphate added to infant formula to reduce lead absorption from the gastrointestinal tract. Subjects were children...

J. D. Sargent

1992-01-01

15

Vitamin D and Calcium Supplementation to Prevent Fractures in Adults: U.S. Preventive Services Task Force ...  

MedlinePLUS

Vitamin D and Calcium Supplementation to Prevent Fractures in Adults: U.S. Preventive Services Task Force Recommendation Statement The full report is titled “Vitamin D and Calcium Supplementation to Prevent Fractures in ...

16

Calcium and acid rebound: a reappraisal.  

PubMed

We review acid rebound, the seemingly paradoxical increase in acid secretion resulting from administration of an antacid. Primarily a laboratory observation, the demonstration of the phenomenon was a major contributing factor to the swift, and possibly unjustified, fall from grace of calcium carbonate in the therapy of peptic ulcer disease despite years of apparently successful use. Calcium, as carbonate or other salts, causes an increase in gastric acid secretion owing, at least in part, to direct ionic stimulation. Another possible mode of action involves antral alkalinization with subsequent gastrin release. Other antacids, notably magnesium hydroxide and aluminum hydroxide, may therefore also cause rebound, but the data in this area are less convincing. Despite the demonstration that acid rebound occurs, no one has thoroughly investigated its clinical import. What limited data actually exist suggest no obvious clinically significant deleterious effect from use of calcium carbonate in peptic ulcer. Because of calcium carbonate's excellent acid-neutralizing capacity, its venerable past record in treating ulcer disease, and recent observations that low-dose antacids heal peptic ulcers, it is appropriate to reevaluate acid rebound, to focus on its clinical significance, if any. PMID:1500660

Hade, J E; Spiro, H M

1992-07-01

17

Acid coal pile drainage prevention  

Microsoft Academic Search

The purpose of the present study was to evaluate different compounds or mixtures to prevent acid coal pile drainage. Acid coal pile drainage refers to the low pH drainage from the water leached through the high sulfur coal piles. Purdue University owns and operates a co-generating power plant that produces steam and electricity from the combustion of coal, gas, and

Sandra L Mansilla-Soto

1999-01-01

18

Calcium-based Lewis acid catalysts.  

PubMed

Recently, Lewis acidic calcium salts bearing weakly coordinating anions such as Ca(NTf?)?, Ca(OTf)?, CaF? and Ca[OCH(CF?)?]? have been discovered as catalysts for the transformation of alcohols, olefins and carbonyl compounds. High stability towards air and moisture, selectivity and high reactivity under mild reaction conditions render these catalysts a sustainable and mild alternative to transition metals, rare-earth metals or strong Brønsted acids. PMID:23712417

Begouin, Jeanne-Marie; Niggemann, Meike

2013-05-24

19

Calcium aluminosilicate glass corrosion by phosphoric acid  

SciTech Connect

The corrosion rates of a series of calcium aluminosilicate and sodium calcium aluminosilicate glasses were determined in three phosphoric acids at several temperatures. The effect of temperature on corrosion rate was determined for one glass in 30 wt % H/sub 3/PO/sub 4/; an activation energy was determined as well. The glasses are virtually insoluble at silica concentrations of >55 wt % SiO/sub 2/ and show extreme solubility at silica concentrations <50 wt %. At the trsnsition composition, a silica-gel layer is formed on the surface.

Thakore, N.C.; Rockett, T.J.

1980-11-01

20

Germination of Bacterial Endospores with Calcium and Dipicolinic Acid  

Microsoft Academic Search

Aerobic and anaerobic bacterial endospores can be germinated if calcium chloride and dipicolinic acid are added to well-washed suspensions. Maximum germination is obtained when the calcium and acid are present in a molar ratio of one or more. This suggests that the 1:1 chelate of calcium and dipicolinic acid is the agent that induces germination.

Hans Riemann; Z. John Ordal

1961-01-01

21

Gastric acid, calcium absorption, and their impact on bone health.  

PubMed

Calcium balance is essential for a multitude of physiological processes, ranging from cell signaling to maintenance of bone health. Adequate intestinal absorption of calcium is a major factor for maintaining systemic calcium homeostasis. Recent observations indicate that a reduction of gastric acidity may impair effective calcium uptake through the intestine. This article reviews the physiology of gastric acid secretion, intestinal calcium absorption, and their respective neuroendocrine regulation and explores the physiological basis of a potential link between these individual systems. PMID:23303909

Kopic, Sascha; Geibel, John P

2013-01-01

22

The Role of Fluoride and Casein Phosphopeptide\\/Amorphous Calcium Phosphate in the Prevention of Erosive\\/Abrasive Wear in an in vitro Model Using Hydrochloric Acid  

Microsoft Academic Search

Objective: To investigate the effect of various fluoride compounds and casein phosphopeptide\\/amorphous calcium phosphate (CPP-ACP) on the reduction of erosive\\/abrasive tooth wear. Methods: Forty enamel samples were prepared from bovine lower incisors, stratified and allocated to 4 groups (1–4). Samples in group 1 remained untreated and served as negative controls. The test samples were treated for 2 min\\/day as follows:

F. J. Wegehaupt; T. Attin

2010-01-01

23

A laboratory study on pteroyl- l-glutamic acid as a scale prevention inhibitor of calcium carbonate in aqueous solution of synthetic produced water  

Microsoft Academic Search

Oil well scale inhibition with green scale inhibitor is a relatively unexplored area. A huge amount of produced water containing various types and amount of residual scale and corrosion inhibitors is discharged into the environment everyday, which has brought focus of environment regulatory bodies and encourages operators to look for greener chemicals. Pteroyl-l-glutamic acid (PGLU) is a type of water

T. Kumar; S. Vishwanatham; S. S. Kundu

2010-01-01

24

Effects of dietary calcium and phosphate on the intestinal interactions between calcium, phosphate, fatty acids, and bile acids.  

PubMed Central

Luminal free fatty acids and bile acids may damage the colonic epithelium and stimulate proliferation, which may increase the risk of colon cancer. It has been suggested that only soluble calcium ions (Ca2+) precipitate fatty acids and bile acids, thus reducing their lytic activity. Consequently, precipitation of luminal Ca2+ by dietary phosphate should inhibit these effects. To evaluate the proposed antagonistic effects of dietary calcium and phosphate, we studied the intestinal interactions between calcium, phosphate, fatty acids, and bile acids in rats fed purified diets that differed only in the concentrations of calcium and phosphate. Increased dietary calcium drastically decreased the solubility of fatty acids in the ileum, colon, and faeces, as well as the solubility of bile acids in the colon and faeces. Although dietary calcium strongly increased the total faecal fatty acid concentration and hardly affected the total faecal bile acid concentration, the fatty acid and bile acid concentrations in faecal water were drastically decreased by dietary calcium. Consequently, the lytic activity of faecal water was decreased. Dietary phosphate did not interfere with these intestinal effects of calcium. These results indicate that dietary phosphate does not inhibit the protective effects of dietary calcium on luminal solubility and the lytic activity of fatty and bile acids.

Govers, M J; Van der Meet, R

1993-01-01

25

Genetic Ablation of Calcium-independent Phospholipase A2? Prevents Obesity and Insulin Resistance during High Fat Feeding by Mitochondrial Uncoupling and Increased Adipocyte Fatty Acid Oxidation*  

PubMed Central

Phospholipases are critical enzyme mediators participating in many aspects of cellular function through modulating the generation of lipid 2nd messengers, membrane physical properties, and cellular bioenergetics. Here, we demonstrate that mice null for calcium-independent phospholipase A2? (iPLA2??/?) are completely resistant to high fat diet-induced weight gain, adipocyte hypertrophy, hyperinsulinemia, and insulin resistance, which occur in iPLA2?+/+ mice after high fat feeding. Notably, iPLA2??/? mice were lean, demonstrated abdominal lipodystrophy, and remained insulin-sensitive despite having a marked impairment in glucose-stimulated insulin secretion after high fat feeding. Respirometry of adipocyte explants from iPLA2??/? mice identified increased rates of oxidation of multiple different substrates in comparison with adipocyte explants from wild-type littermates. Shotgun lipidomics of adipose tissue from wild-type mice demonstrated the anticipated 2-fold increase in triglyceride content after high fat feeding. In sharp contrast, the adipocyte triglyceride content was identical in iPLA2??/? mice fed either a standard diet or a high fat diet. Respirometry of skeletal muscle mitochondria from iPLA2??/? mice demonstrated marked decreases in state 3 respiration using multiple substrates whose metabolism was uncoupled from ATP production. Shotgun lipidomics of skeletal muscle revealed a decreased content of cardiolipin with an altered molecular species composition thereby identifying the mechanism underlying mitochondrial uncoupling in the iPLA2??/? mouse. Collectively, these results identify iPLA2? as an obligatory upstream enzyme that is necessary for efficient electron transport chain coupling and energy production through its participation in the alterations of cellular bioenergetics that promote the development of the metabolic syndrome.

Mancuso, David J.; Sims, Harold F.; Yang, Kui; Kiebish, Michael A.; Su, Xiong; Jenkins, Christopher M.; Guan, Shaoping; Moon, Sung Ho; Pietka, Terri; Nassir, Fatiha; Schappe, Timothy; Moore, Kristin; Han, Xianlin; Abumrad, Nada A.; Gross, Richard W.

2010-01-01

26

Calcium stimulation of gastrin and gastric acid secretion: effect of small doses of calcium carbonate.  

PubMed Central

Oral calcium carbonate (0-5 g, pH 9-4) increased serum gastrin and gastric acid output with slight but insignificant change in serum calcium. A similar rise in serum calcium during an intravenous infusion of calcium gluconate failed to increase serum gastrin and gastric acid output. Both intragastric calcium actions were abolished by acidification of the calcium carbonate solution (pH 1-0). The increase in serum gastrin and gastric acid output after intragastric calcium carbonate was not affected, however, by a simultaneous intraduodenal acid load. Equivalent neutralising doses of magnesium hydroxide (pH 9-4) did not increase serum gastrin and gastric acid output above basal levels, whereas antral acidification with 20 ml 0-1 N HCl resulted in a slight decrease in serum gastrin. Intraduodenal calcium carbonate (pH 3-0) also increased serum gastrin and gastric acid output, whereas an equivalent volume of intraduodenal saline (pH 3-0) had no effect. These findings indicate that calcium increases serum gastrin by local stimulation of antral and duodenal mucosa. They also suggest that the action of calcium on gastric secretion is partly mediated by gastrin.

Behar, J; Hitchings, M; Smyth, R D

1977-01-01

27

Plasma phospholipid arachidonic acid content and calcium metabolism in idiopathic calcium nephrolithiasis  

Microsoft Academic Search

Plasma phospholipid arachidonic acid content and calcium metabolism in idiopathic calcium nephrolithiasis.BackgroundReports of an increase in plasma and erythrocyte phospholipid arachidonic acid content and in urinary prostaglandin E2 (PGE2) excretion in patients with idiopathic calcium nephrolithiasis suggested their crucial role in the pathogenesis of hypercalciuria, a well-known risk factor for lithogenesis.MethodsTo confirm this hypothesis, 15 healthy subjects and 20 nephrolithiasis

Bruno Baggio; Alessandro Budakovic; Maria Angela Nassuato; Giuseppe Vezzoli; Enzo Manzato; Giovanni Luisetto; Martina Zaninotto

2000-01-01

28

Interaction of Citric or Hydrochloric Acid with Calcium Fluorapatite: Precipitation of Calcium Fluoride  

Microsoft Academic Search

The interaction of citric acid (H3Ci) with calcium fluorapatite(Ca10 F2(PO4)6) was explored for two reasons: (i) to determine the role of the acid in the dissolution process and hence in the mechanism of tooth fluoridation and (ii) to determine whether there is any formation of calcium citrate. It was found that the concentration of calcium or fluoride ions is not

Dwarika Nath Misra

1999-01-01

29

Is docosahexaenoic acid more effective than eicosapentaenoic acid for increasing calcium bioavailability?  

PubMed

Experimental animal and human studies have indicated that long chain polyunsaturated fatty acids (LCPUFA) may enhance calcium absorption, reduce urinary calcium excretion, and increase bone calcium content. In the present study, the effect of LCPUFA, as provided in evening primrose oil, fish and tuna oils, on calcium bioavailability was investigated. Growing male rats were fed a semi-synthetic diet for 6 weeks, after which calcium absorption, bone mineral density (ex vivo), bone calcium content, and bone biomechanics were measured. Calcium absorption, ex vivo bone mineral density, and bone calcium content were significantly higher in the animals fed tuna oil compared with those of a control group fed corn oil. Significant correlations were found between the docosahexaenoic acid (DHA) (22:6n-3) content of the red cell membranes and bone density and bone calcium content. DHA increased accretion of calcium in bone significantly more so than eicosapentaenoic acid (EPA) (20:5n-3). PMID:16154334

Kruger, Marlena C; Schollum, Linda M

2005-11-01

30

Oxalic acid decreases calcium absorption in rats  

SciTech Connect

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

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

1987-11-01

31

Effects of calcium fertilization and acid mist on calcium concentration ...  

Treesearch

... which appears to be a major factor in the decline of montane populations of the ... Other studies have shown increases in calcium (Ca) concentration in canopy ... play a role in the development of cold tolerance or in stress response to cold.

32

Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using chitosan and citric acid  

Microsoft Academic Search

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan solution as the liquid phase and tetra\\u000a calcium phosphate (TTCP), dicalcium phosphate anhydrous (DCPA) and calcium sulfate hemihydrate (CSH) powders as the solid\\u000a phase was prepared. Four groups containing different percentages (0–30%) of calcium sulfate hemihydrate (CSH, CaSO4 · 0.5H2O) were investigated. Initial setting times for IBS with CSH

Ho-Yeon Song; A. H. M. Esfakur Rahman; Byong-Taek Lee

2009-01-01

33

Calcification Prevention Tablets.  

National Technical Information Service (NTIS)

Citric acid tablets, which slowly release citric acid when flushed with water, are under development by the Navy for calcification prevention. The citric acid dissolves calcium carbonate deposits and chelates the calcium. For use in urinals, a dispenser i...

G. A. Lindsay M. A. Hasting M. A. Gustavson

1991-01-01

34

Thermochemical characteristics of reactions of calcium with perchloric acid  

NASA Astrophysics Data System (ADS)

The enthalpy of reaction of metallic calcium with perchloric acid was measured for the first time in a sealed swinging calorimeter equipped with an isothermal shell. Standard enthalpies of formation of calcium ion in an infinitely diluted aqueous solution (-542.8 ± 1.0 kJ/mol) and calcium chloride in crystal state (-794.9 ± 1.0 kJ/mol) were calculated according to the results obtained with the use of published data.

Monaenkova, A. S.; Tiflova, L. A.

2012-05-01

35

Preventing ?-Cell Loss and Diabetes With Calcium Channel Blockers  

PubMed Central

Although loss of functional ?-cell mass is a hallmark of diabetes, no treatment approaches that halt this process are currently available. We recently identified thioredoxin-interacting protein (TXNIP) as an attractive target in this regard. Glucose and diabetes upregulate ?-cell TXNIP expression, and TXNIP overexpression induces ?-cell apoptosis. In contrast, genetic ablation of TXNIP promotes endogenous ?-cell survival and prevents streptozotocin (STZ)- and obesity-induced diabetes. Finding an oral medication that could inhibit ?-cell TXNIP expression would therefore represent a major breakthrough. We were surprised to discover that calcium channel blockers inhibited TXNIP expression in INS-1 cells and human islets and that orally administered verapamil reduced TXNIP expression and ?-cell apoptosis, enhanced endogenous insulin levels, and rescued mice from STZ-induced diabetes. Verapamil also promoted ?-cell survival and improved glucose homeostasis and insulin sensitivity in BTBR ob/ob mice. Our data further suggest that this verapamil-mediated TXNIP repression is conferred by reduction of intracellular calcium, inhibition of calcineurin signaling, and nuclear exclusion and decreased binding of carbohydrate response element–binding protein to the E-box repeat in the TXNIP promoter. Thus, for the first time, we have identified an oral medication that can inhibit proapoptotic ?-cell TXNIP expression, enhance ?-cell survival and function, and prevent and even improve overt diabetes.

Xu, Guanlan; Chen, Junqin; Jing, Gu; Shalev, Anath

2012-01-01

36

Evidence that increased calcium intake does not prevent early postmenopausal bone loss  

Microsoft Academic Search

Calcium's ability to prevent bone loss in early postmenopausal women is controversial. We used data on 394 women from the placebo group of the Early Postmenopausal Interventional Cohort study, a clinical trial of alendronate, to investigate the relation of calcium intake to bone loss. Calcium intake was recorded, and bone mineral density (BMD) (in the lumbar spine, total body, forearm,

David J. Hosking; Philip D. Ross; Desmond E. Thompson; Richard D. Wasnich; Michael McClung; Nina H. Bjarnason; Pernille Ravn; Giovanni Cizza; Marianne Daley; A. John Yates

1998-01-01

37

[Randomized trials in the prevention of recurrent calcium oxalate stones].  

PubMed

Kidney stone, with or without lumbar pain, is a major health care problem because of its prevalence and cost for both the patient and the society. Although, surgical procedures are well known, medical treatment and recurrences prophylaxis are uncodified. Fifteen stone recurrence prevention studies have been reviewed, evaluating dietary intake and drugs. The most important factor is a daily diuresis of at least 2 liters. Calcium intake shouldn't be restricted, whereas oxalate, sodium, and protein intakes have to be limited. Hyper and normocalciuretic kidney stone formers improve their outcome with thiazide or indapamide treatment. Hyperuricosuria justifies allopurinol. Potassium citrate (without sodium) may decrease recurrence risk, even in patients without hypocitraturia. PMID:14584297

Presne, C; Monge, M; Bataille, P; el Esper, N; Choukroun, G; Fournier, A

2003-01-01

38

Meta-analysis of the effect of the acid-ash hypothesis of osteoporosis on calcium balance.  

PubMed

The acid-ash hypothesis posits that protein and grain foods, with a low potassium intake, produce a diet acid load, net acid excretion (NAE), increased urine calcium, and release of calcium from the skeleton, leading to osteoporosis. The objectives of this meta-analysis were to assess the effect of changes in NAE, by manipulation of healthy adult subjects' acid-base intakes, on urine calcium, calcium balance, and a marker of bone metabolism, N-telopeptides. This meta-analysis was limited to studies that used superior methodological quality for the study of calcium metabolism. We systematically searched the literature and included studies if subjects were randomized to the interventions and followed the recommendations of the Institute of Medicine's Panel on Calcium and Related Nutrients for calcium studies. Five of 16 studies met the inclusion criteria. The studies altered the amount and/or type of protein. Despite a significant linear relationship between an increase in NAE and urinary calcium (p < 0.0001), there was no relationship between a change of NAE and a change of calcium balance (p = 0.38; power = 94%). There was no relationship between a change of NAE and a change in the marker of bone metabolism, N-telopeptides (p = 0.95). In conclusion, this meta-analysis does not support the concept that the calciuria associated with higher NAE reflects a net loss of whole body calcium. There is no evidence from superior quality balance studies that increasing the diet acid load promotes skeletal bone mineral loss or osteoporosis. Changes of urine calcium do not accurately represent calcium balance. Promotion of the "alkaline diet" to prevent calcium loss is not justified. PMID:19419322

Fenton, Tanis R; Lyon, Andrew W; Eliasziw, Michael; Tough, Suzanne C; Hanley, David A

2009-11-01

39

Ascorbic acid, calcium, phosphorus and magnesium intake variations: effects on calcium, phosphorus and magnesium utilization by human adults  

SciTech Connect

The objective of the study was to determine the effects of feeding two levels of ascorbic acid, calcium, phosphorus, magnesium and ascorbic acid on the apparent utilization of calcium, phosphorus and magnesium by healthy, human adult subjects. During 4 randomly-arranged experimental periods of 7 days each, a laboratory-controlled diet alone or with supplements of ascorbic acid, dicalcium phosphate or magnesium oxide was fed to the 18 subjects. Results indicated that ascorbic acid supplementation tended to reduce urinary phosphorus loss and to slightly increase fecal phosphorus loss so that overall phosphorus balances became more positive. Conversely, under these conditions, urinary calcium losses were little affected but fecal calcium losses were increased resulting in an overall decrease in calcium balance with ascorbic acid supplementation. Ascorbic acid supplementation resulted in decreased urine and fecal losses of magnesium and more positive magnesium balances. Magnesium supplementation resulted in more positive calcium and phosphorus balances as did calcium phosphate supplementation on magnesium balance.

Kies, C.; Brennan, M.A.; Parks, S.K.; Stauffer, D.J.; Wang, H.Y.; Young, S.F.; Fox, H.M.

1986-03-01

40

Prenatal calcium supplementation and postpartum depression: an ancillary study to a randomized trial of calcium for prevention of preeclampsia  

Microsoft Academic Search

Summary  \\u000a Nulliparous women, between 11 and 21 weeks gestation, were randomized to receive either placebo or 2,000 mg elemental calcium\\u000a per day as subjects in the NIH-sponsored Calcium for Preeclampsia Prevention (CPEP) trial. Six weeks following delivery, a\\u000a demographic and medical history questionnaire, and the Edinburgh Postnatal Depression Scale (EPDS), was mailed to subjects\\u000a in two CPEP sites, Portland, OR

J. Harrison-Hohner; S. Coste; V. Dorato; L. B. Curet; D. McCarron; D. Hatton

2001-01-01

41

Partial depletion of sarcoplasmic reticulum calcium does not prevent calcium sparks in rat ventricular myocytes.  

PubMed Central

1. The exact nature of calcium sparks in the heart remains highly controversial. We sought to determine whether calcium sparks arise from a single or multiple calcium release channels/ ryanodine receptors in the sarcoplasmic reticulum (SR). If their genesis involves a calcium-coupled recruitment of multiple channels, calcium sparks might be abolished by a modest depletion of SR calcium (because of the decrease in unitary calcium flux and hence a decrease in the gain of local calcium-induced calcium release). If, on the other extreme, calcium sparks are produced despite severe SR depletion, the single-channel origin will be preferred. 2. Spontaneous calcium sparks were studied in rat ventricular myocytes using confocal microscopy and the fluorescent calcium probe fluo-3. A computer algorithm was developed to count and measure objectively calcium sparks in linescan images. 3. Thapsigargin (25-150 nM) depleted caffeine-releasable SR calcium by up to 64%, in a dose- and time-dependent manner, without altering the resting cytosolic calcium level. During SR depletion, calcium sparks were robustly observed, albeit at reduced frequency (> or = 30% of control) and amplitude (> or = 60% of control). 4. Due to the reduced detectability of small sparks against noise background, the observed data would overestimate reduction in spark frequency but underestimate amplitude reduction. After correction for this detection bias, we found that the spark frequency was independent of SR load, whereas the amplitude was proportional to load. 5. We conclude that, although spark amplitude depends on SR filling status, the frequency of spark generation is independent of SR calcium load, and therefore independent of the local calcium release rate. This implies that sparks are single-channel events, or collective events that are well above threshold for local regeneration. Additionally, our results suggest that intraluminal SR calcium, at normal or low loads, does not play a major role in the regulation of on-gating of the ryanodine receptor. Images Figure 1

Song, L S; Stern, M D; Lakatta, E G; Cheng, H

1997-01-01

42

Polyunsaturated Fatty Acids Modulate Sodium and Calcium Currents in CA1 Neurons  

Microsoft Academic Search

Recent evidence indicates that long-chain polyunsaturated fatty acids (PUFAs) can prevent cardiac arrhythmias by a reduction of cardiomyocyte excitability. This was shown to be due to a modulation of the voltage-dependent inactivation of both sodium (INa) and calcium (ICa) currents. To establish whether PUFAs also regulate neuronal excitability, the effects of PUFAs on INa and ICa were assessed in CA1

M. Vreugdenhil; C. Bruehl; R. A. Voskuyl; J. X. Kang; A. Leaf; W. J. Wadman

1996-01-01

43

Comparative Effects of Boric Acid and Calcium Fructoborate on Breast Cancer Cells  

Microsoft Academic Search

Recent studies suggested that boron has a chemo-preventive role in prostate cancer. In the present report, we investigated\\u000a the effects of calcium fructoborate (CF) and boric acid (BA) on activation of the apoptotic pathway in MDA-MB-231 human breast\\u000a cancer cells. Exposure to BA and CF inhibited the proliferation of breast cancer cells in a dose-dependent manner. Treatment\\u000a with CF but

R. Scorei; Raluca Ciubar; Cristina M. Ciofrangeanu; Valentina Mitran; Anisoara Cimpean; Dana Iordachescu

2008-01-01

44

Comparative absorption of calcium sources and calcium citrate malate for the prevention of osteoporosis.  

PubMed

Anthropologically speaking, humans were high consumers of calcium until the onset of the Agricultural Age, 10,000 years ago. Current calcium intake is one-quarter to one-third that of our evolutionary diet and, if we are genetically identical to the Late Paleolithic Homo sapiens, we may be consuming a calcium-deficient diet our bodies cannot adjust to by physiologic mechanisms. Meta-analyses of calcium and bone mass studies demonstrate supplementation of 500 to 1500 mg calcium daily improves bone mass in adolescents, young adults, older men, and postmenopausal women. Calcium citrate malate has high bioavailability and thus has been the subject of calcium studies in these populations. Positive effects have been seen in prepubertal girls, adolescents, and postmenopausal women. The addition of trace minerals and vitamin D in separate trials has improved the effect of calcium citrate malate on bone density and shown a reduction of fracture risk. PMID:10231607

Patrick, L

1999-04-01

45

Comparative Absorption of Calcium Sources and Calcium Citrate Malate for the Prevention of Osteoporosis  

Microsoft Academic Search

Anthropologically speaking, humans were high consumers of calcium until the onset of the Agricultural Age, 10,000 years ago. Current calcium intake is one-quarter to one-third that of our evolutionary diet and, if we are genetically identical to the Late Paleolithic Homo sapiens, we may be consuming a calcium-deficient diet our bodies cannot adjust to by physiologic mechanisms. Meta-analyses of calcium

Lyn Patrick

1999-01-01

46

Gastrin Releases a Blood Calcium-Lowering Peptide from the Acid-Producing Part of the Rat Stomach  

Microsoft Academic Search

Gastrin-17 induces hypocalcemia in the rat without stimulating calcitonin release. The gastrin-induced hypocalcemia persisted after thyroparathyroidectomy or parathyroidectomy. In contrast, gastrectomy or extirpation of the acid-producing part of the stomach prevented the hypocalcemic effect, suggesting the involvement of the proximal stomach in the gastrin-evoked lowering of blood calcium. The drop in blood calcium upon injection of gastrin-17 did not reflect

Per Persson; Rolf Hakanson; Jan Axelson; Frank Sundler

1989-01-01

47

21 CFR 872.3490 - Carboxymethylcellulose sodium and/or polyvinylmethylether maleic acid calcium-sodium double salt...  

Code of Federal Regulations, 2013 CFR

...and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive...and/or polyvinylmethylether maleic acid calcium-sodium double salt denture adhesive...and/or polyvinylmethylether maleic acid calcium-sodium double salt denture...

2013-04-01

48

Acidic calcium stores open for business: expanding the potential for intracellular Ca2+ signaling  

PubMed Central

Changes in cytosolic calcium concentration are crucial for a variety of cellular processes in all cells. It has long been appreciated that calcium is stored and released from intracellular calcium stores such as the endoplasmic reticulum. However, emerging evidence indicates that calcium is also dynamically regulated by a seemingly disparate collection of acidic organelles. Here, we review the defining features of these acidic calcium stores and highlight recent progress in understanding the mechanisms of uptake and release of calcium from these stores. We also examine the nature of calcium buffering within the stores and summarize the physiological and patho-physiological significance of these ubiquitous organelles in calcium signaling.

Patel, Sandip; Docampo, Roberto

2010-01-01

49

EFFECT ON GROWTH AND CALCIUM ASSIMILATION OF CITRIC ACID â€\\  

Microsoft Academic Search

In an earlier paper (Lanford, '39), experiments were re ported in which the addition of a moderate amount of orange juice to a wheat-and-milk diet caused the assimilation by rats of a larger proportion of the calcium in the food mixture. The present series was planned to test whether the mixture of citric acid and citrates in the orange juice

CAROLINE SHERMAN LANFORU

50

Lifelong calcium intake and prevention of bone fragility in the aged  

Microsoft Academic Search

Summary  Primary prevention of osteoporosis involves achieving the full genetic potential for bone mass. Secondary prevention is concerned\\u000a with protecting what bone mass a woman may have at her current age. Calcium plays an important role in both. Calcium requirement\\u000a varies with stage of growth, with physiological drains (e.g., pregnancy and lactation), and with factors that influence absorption\\u000a and excretory loss

Robert P. Heaney

1991-01-01

51

Phytic acid plus calcium, but not phytic acid alone, decreases fluoride bioavailability in the rat  

Microsoft Academic Search

Results of in vitro studies have suggested that fluoride becomes insoluble when some soy-based infant formulas are diluted with fluoridated water because of the presence of phytate, added calcium or a combination of these factors. The present study was designed to test this hypothesis in vivo. Male albino rats were fed a purified diet containing phytic acid, calcium and fluoride

Cerklewski

1991-01-01

52

40 CFR 721.10382 - Diphosphoric acid, calcium salt (1:1).  

Code of Federal Regulations, 2013 CFR

...2013-07-01 false Diphosphoric acid, calcium salt (1:1). 721.10382 Section... § 721.10382 Diphosphoric acid, calcium salt (1:1). (a) Chemical substance...substance identified as diphosphoric acid, calcium salt (1:1) (PMN...

2013-07-01

53

Sanitary dips with calcium propionate, calcium chloride, or a calcium amino acid chelate maintain quality and shelf stability of fresh-cut honeydew chunks  

Microsoft Academic Search

Freshly cut honeydew chunks were dipped for 30 s in a solution containing 1.9 mM hypochlorous acid (ClO) without or with a 40 mM concentration of calcium (Ca) propionate, Ca amino acid chelate formulation (Ca chelate), calcium chloride (CaCl2), or not treated. Respiration and ethylene production rates, firmness, translucency, microbiological and sensory characteristics, surface color, volatile abundance, and tissue calcium

Robert A. Saftner; Jinhe Bai; Judith A. Abbott; Yuen S. Lee

2003-01-01

54

Abscisic acid controls calcium-dependent egress and development in Toxoplasma gondii.  

PubMed

Calcium controls a number of critical events, including motility, secretion, cell invasion and egress by apicomplexan parasites. Compared to animal and plant cells, the molecular mechanisms that govern calcium signalling in parasites are poorly understood. Here we show that the production of the phytohormone abscisic acid (ABA) controls calcium signalling within the apicomplexan parasite Toxoplasma gondii, an opportunistic human pathogen. In plants, ABA controls a number of important events, including environmental stress responses, embryo development and seed dormancy. ABA induces production of the second-messenger cyclic ADP ribose (cADPR), which controls release of intracellular calcium stores in plants. cADPR also controls intracellular calcium release in the protozoan parasite T. gondii; however, previous studies have not revealed the molecular basis of this pathway. We found that addition of exogenous ABA induced formation of cADPR in T. gondii, stimulated calcium-dependent protein secretion, and induced parasite egress from the infected host cell in a density-dependent manner. Production of endogenous ABA within the parasite was confirmed by purification (using high-performance liquid chromatography) and analysis (by gas chromatography-mass spectrometry). Selective disruption of ABA synthesis by the inhibitor fluridone delayed egress and induced development of the slow-growing, dormant cyst stage of the parasite. Thus, ABA-mediated calcium signalling controls the decision between lytic and chronic stage growth, a developmental switch that is central in pathogenesis and transmission. The pathway for ABA production was probably acquired with an algal endosymbiont that was retained as a non-photosynthetic plastid known as the apicoplast. The plant-like nature of this pathway may be exploited therapeutically, as shown by the ability of a specific inhibitor of ABA synthesis to prevent toxoplasmosis in the mouse model. PMID:18185591

Nagamune, Kisaburo; Hicks, Leslie M; Fux, Blima; Brossier, Fabien; Chini, Eduardo N; Sibley, L David

2008-01-10

55

Detection of bound phenolic acids: prevention by ascorbic acid and ethylenediaminetetraacetic acid of degradation of phenolic acids during alkaline hydrolysis  

Microsoft Academic Search

The experimental conditions commonly used to detect bound phenolic acids by alkaline hydrolysis result in loss of several phenolic acids, particularly dihydroxy-derivatives (caffeic acid, dihydrocaffeic acid, homogentisic acid). In this study we show that the addition of ascorbic acid, a strong antioxidant, and ethylenediaminetetraacetic acid, a metal chelator, totally prevent the loss of phenolic acids during alkaline hydrolysis. In these

M Nardini; E Cirillo; F Natella; D Mencarelli; A Comisso; C Scaccini

2002-01-01

56

Supplemental calcium for the prevention of hip fracture: Potential health-economic benefits  

Microsoft Academic Search

We assessed the cost-effectiveness of daily calcium supplementation for the prevention of primary osteoporotic hip fractures. The assessment was based on our meta-analysis of the published relative-risk estimates from 3 double-masked, placebo-controlled, clinical trials and our analysis of raw data from the National Health and Nutrition Examination Survey 1988–1994 on the daily intake of calcium supplements by adults in the

Adrianne Bendich; Shelah Leader; Pradip Muhuri

1999-01-01

57

Prevention of calcium sulfate formation in seawater desalination by ion exchange  

Microsoft Academic Search

In mechanical vapor compression (MVC) desalination, high operating temperatures (>120°C) allow for high heat transfer coefficients and reduced compressor size, both of which lower total capital costs. To prevent formation of calcium sulfate scale on high-temperature desalination heat exchangers, the inverse solubility of calcium sulfate requires high sulfate removal. To selectively remove sulfate from seawater, a weak-base anion-exchange resin (Relite

Li Zhu; Cesar B. Granda; Mark T. Holtzapple

2011-01-01

58

Maleic acid based scale inhibitors for calcium sulfate scale inhibition in high temperature application  

Microsoft Academic Search

In anhydrite rich reservoir rock, calcium sulfate is one of the dominant scale components which unlike carbonate scale are not easily removable by acid or dissolver treatment. To inhibit calcium sulfate scale formation in high temperature producing brine water systems, maleic acid–acrylic acid and maleic acid–acrylamide copolymers of appropriate molecular weight were synthesized and characterized and inhibition efficiency of the

B. Senthilmurugan; B. Ghosh; S. S. Kundu; M. Haroun; B. Kameshwari

2010-01-01

59

Partial prevention of calcium paradox in isolated perfused rat hearts by diltiazem.  

PubMed

It is well known that excessive calcium entry into the myocardial cells may contribute considerably to damage of the heart caused by postischemic reperfusion. The effect of increased calcium entry on hemodynamics, energy metabolism and histochemically estimated enzyme activities in isolated, perfused (Langendorff) rat heart preparation was investigated using calcium paradox (CaPX) as a model. After a 15 min period of stabilized perfusion of the heart, CaPX was induced at 37 degrees C by 2.5 min lasting calcium depletion (calcium-free perfusion) and subsequent calcium repletion (10 min). Changes induced by CaPX concerned loss of electrical and mechanical activities of the heart, significant decreases in coronary flow and ATP, ADP and the total content of adenine nucleotides in tissue as well as considerable depression in ATPases, SDH, beta-HBDH, LDH and glycogen phosphorylase activities in the myocardium. Diltiazem in concentration of 4.0 mumol.l-1 applied prior to calcium depletion and during calcium repletion prevented partially the deterioration of cardiac function by improving contractility and electrical activity of the heart as well as the coronary flow. The effect of diltiazem in concentration of 0.4 mumol.l-1 was less expressed. After both concentrations of diltiazem used, a better preserved ultrastructure, higher activities of the enzymes investigated, significantly higher ATP and total adenine nucleotide levels were seen in the myocardium as compared to the untreated controls. PMID:2525034

Ziegelhöffer, A; Ravingerová, T; Tribulová, N; Slezák, J; Okolicány, J; Trégerová, V; Krause, E G; Bartel, S

1989-01-01

60

Prevention of nutritional rickets in Nigerian children with dietary calcium supplementation.  

PubMed

Nutritional rickets in Nigerian children usually results from dietary calcium insufficiency. Typical dietary calcium intakes in African children are about 200mg daily (approximately 20-28% of US RDAs for age). We sought to determine if rickets could be prevented with supplemental calcium or with an indigenous food rich in calcium. We enrolled Nigerian children aged 12 to 18months from three urban communities. Two communities were assigned calcium, either as calcium carbonate (400mg) or ground fish (529±109mg) daily, while children in all three communities received vitamin A (2500IU) daily as placebo. Serum markers of mineral homeostasis and forearm bone density (pDEXA) were measured and radiographs were obtained at enrollment and after 18months of supplementation. The overall prevalence of radiographic rickets at baseline was 1.2% and of vitamin D deficiency [serum 25(OH)D<12ng/ml] 5.4%. Of 647 children enrolled, 390 completed the 18-month follow-up. Rickets developed in 1, 1, and 2 children assigned to the calcium tablet, ground fish, and control groups, respectively (approximate incidence 6.4/1000 children/year between 1 and 3years of age). Children who developed rickets in the calcium-supplemented groups had less than 50% adherence. Compared with the group that received no calcium supplementation, the groups that received calcium had a greater increase in areal bone density of the distal and proximal 1/3 radius and ulna over time (P<0.04). We conclude that calcium supplementation increased areal bone density at the radius and ulna, but a larger sample size would be required to determine its effect on the incidence of rickets. PMID:22373953

Thacher, Tom D; Fischer, Philip R; Isichei, Christian O; Zoakah, Ayuba I; Pettifor, John M

2012-02-22

61

Calcium ion binding to a soil fulvic acid using a donnan potential model  

USGS Publications Warehouse

Calcium ion binding to a soil fulvic acid (Armadale Bh Horizon) was evaluated over a range of calcium ion concentrations, from pH 3.8 to 7.3, using potentiometric titrations and calcium ion electrode measurements. Fulvic acid concentration was constant (100 milligrams per liter) and calcium ion concentration varied up to 8 X 10-4 moles per liter. Experiments discussed here included: (1) titrations of fulvic acid-calcium ion containing solutions with sodium hydroxide; and (2) titrations of fully neutralized fulvic acid with calcium chloride solutions. Apparent binding constants (expressed as the logarithm of the value, log ??app) vary with solution pH, calcium ion concentration, degree of acid dissociation, and ionic strength (from log ??app = 2.5 to 3.9) and are similar to those reported by others. Fulvic acid charge, and the associated Donnan Potential, influences calcium ion-fulvic acid ion pair formation. A Donnan Potential corrrection term allowed calculation of intrinsic calcium ion-fulvic acid binding constants. Intrinsic binding constants vary from 1.2 to 2.5 (the average value is about log??= 1.6) and are similar to, but somewhat higher than, stability constants for calcium ion-carboxylic acid monodentate complexes. ?? by Oldenbourg Wissenschaftsverlag, Mu??nchen.

Marinsky, J. A.; Mathuthu, A.; Ephraim, J. H.; Reddy, M. M.

1999-01-01

62

Soil-calcium depletion linked to acid rain and forest growth in the eastern United States  

USGS Publications Warehouse

Since the discovery of acid rain in the 1970's, scientists have been concerned that deposition of acids could cause depletion of calcium in forest soils. Research in the 1980's showed that the amount of calcium in forest soils is controlled by several factors that are difficult to measure. Further research in the 1990's, including several studies by the U.S. Geological Survey, has shown that (1) calcium in forest soils has decreased at locations in the northeastern and southeastern U.S., and (2) acid rain and forest growth (uptake of calcium from the soil by roots) are both factors contributing to calcium depletion.

Lawrence, Gregory B.; Huntington, T. G.

1999-01-01

63

Fabrication of calcium phosphate–calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid  

Microsoft Academic Search

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose\\u000a (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate\\u000a (CSD, CaSO4·2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid\\u000a phase

Van Viet Thai; Byong-Taek Lee

2010-01-01

64

Calcium  

MedlinePLUS

... Office of Dietary Supplements Dietary Supplement Fact Sheet: Calcium QuickFacts Datos en español Health Professional Other Resources Create PDF What is calcium and what does it do? Calcium is a ...

65

Direct Identification of the Calcium-Binding Amino Acid, gamma -carboxyglutamate, in Mineralized Tissue  

Microsoft Academic Search

A direct approach has been developed for quantitative identification of the calcium-binding amino acid, gamma -carboxyglutamate, in proteins. This should be advantageous for the study of numerous systems where specific roles for the binding of calcium or other divalent cations are suspected. Investigation of mineralized tissue, where calcium-binding proteins are implicated in the mineralization process, revealed that gamma -carboxyglutamate was

Peter V. Hauschka; Jane B. Lian; Paul M. Gallop

1975-01-01

66

Gibberellic Acid and Abscisic Acid Coordinately Regulate Cytoplasmic Calcium and Secretory Activity in Barley Aleurone Protoplasts  

Microsoft Academic Search

The effects of gibberellic acid (GA_3) and abscisic acid (ABA) on the temporal and spatial dynamics of cytosolic calcium concentration ([Ca2+]_i) in aleurone protoplasts of barley (Hordeum vulgare L. cv. Himalaya) were measured by using fluorescence ratio analysis and confocal microscopy. After 4-6 h of treatment, GA_3 induced a sustained increase in [Ca2+]_i from 50 to 150 nM in aleurone

Simon Gilroy; Russell L. Jones

1992-01-01

67

The impact of osteoporosis prevention programs on calcium intake: a systematic review.  

PubMed

Little is known about the dimensions of osteoporosis prevention programs essential to changing health behaviors. The purpose of this review was to determine the impact of select characteristics of structured osteoporosis prevention programs on calcium intake in women. This systematic review included 12 experimental and quasi-experimental studies conducted internationally with adult women participants. Studies were more likely to demonstrate differences when they were conducted outside the U.W.; participants had lower baseline calcium intake; and interventions were multi-dimensional and included factual information, skill training, and social contact delivered dynamically over time. The results document extensive variability across participants, programs, and measures. There is a need to document the source (total and sub-total) of calcium intake, to provide the necessary data to calculate effect sizes to enable comparison across studies, and to identify those moderating factors (such as menopausal status) that affect the ability to determine differences between sub-groups. Results indicate health behavior change is more likely to occur when patient-centered interventions designed to increase knowledge and health beliefs, skills and abilities, and social facilitation are delivered over time. There is an urgent need for the development and testing of new health behavior change theories, prevention programs, and delivery media to support and complement health care providers in the prevention and management of this common, debilitating condition. PMID:23314270

Ryan, P; Schlidt, A; Ryan, C

2013-01-12

68

High-Melting Lubricants Based on Complex Calcium Soaps of Commercial Synthetic Fatty Acids.  

National Technical Information Service (NTIS)

Synthetic fatty acids can be used in the production of high-quality complex calcium lubricants which can be used in a wide range of temperatures. The best calcium lubricants are obtained when using the wide heat-treated and distilled fraction of acids C10...

M. B. Nakonechnaya N. S. Goshko V. V. Sinitsyn Y. L. Ishchuk

1969-01-01

69

Arachidonic Acid and Prostaglandins Enhance Potassium-Stimulated Calcium InFlux into Rat Brain Synaptosomes.  

National Technical Information Service (NTIS)

Exogenous administration of arachidonic acid, prostaglandins PGF2 alpha, PGD2 and PGE2 increased potassium-stimulated uptake of calcium in rat brain synaptosomes from the brain of the rat, but had no effect on the basal uptake of calcium. Arachidonic acid...

S. B. Kandasamy W. A. Hunt

1990-01-01

70

Calcium  

MedlinePLUS

... strong bones and teeth. Why Do I Need Calcium? Bones grow rapidly during adolescence, and teens need ... and canned salmon with bones. Back Continue Working Calcium Into Your Diet Looking for ways to up ...

71

Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid  

PubMed Central

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4·2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37°C.

Thai, Van Viet

2010-01-01

72

Coprecipitation of radium with calcium and strontium from acid solutions using crown ether and tungstosilicic acid  

Microsoft Academic Search

The coprecipitation of radium with strontium or calcium, 18C6 and tungstosilicic acid was studied. It was determined that radium is coprecipitated with Ca and Sr and mixed compounds are fomed. It was also find the yield of Ra depends on the ratio of stability constants of metals present in a solution with 18C6. The stability constant of Ra with 18C6

P. Rajec; V. Mikulaj; P. Husar?ik; V. Švec

1997-01-01

73

Dietitians’ Educational Levels and Beliefs Related to Intentions to Recommend Calcium and Vitamin D Supplements for Osteoporosis Prevention and Treatment  

Microsoft Academic Search

The objective of this research was to examine whether registered dietitians’ educational levels or beliefs concerning calcium and vitamin D supplementation are related to their intended behavior in recommending calcium and\\/or vitamin D supplements to patients for osteoporosis prevention and treatment. A mail questionnaire was used to survey the participants. Three hundred twenty registered dietitians were randomly selected from the

R. A. Folk; E. Parham; S. M. Miller; L. Robinson

1999-01-01

74

Hippuric acid as a modifier of calcium oxalate crystallisation.  

PubMed

Hippuric acid (HA) originating from the conjugation of benzoic acid with glycine is a physiological component of human urine. Findings suggest that HA inhibits calcium oxalate (CaOx) growth and considerably enhances the CaOx solubility in artificial urine. Thus, it is assumed that HA is a major modifier of CaOx formation. However, only a slight CaOx growth inhibition of 1-8% was also reported. These values were also derived from artificial urine. The key mechanism, which led HA to be of interest in urolithiasis research is the fact that in presence of Ca2+ ions HA can form a hippurate complex. By forming such a complex, Ca2+ concentration in urine decreases, and as a consequence, CaOx formation is inhibited. This study was performed in order to clarify the role of HA in native and artificial urine. Biochemical analyses to calculate the relative CaOx supersaturations and crystallisation experiments using an in-line laser probe were examined. BONN Risk Indices indicating the risk of CaOx crystallisation were calculated from the results of the crystallisation experiments. The results obtained from artificial as well as from native urines showed that HA has no significant effects on CaOx formation. We suggest that HA plays only a minor role as a crystallisation modifier in human urine. PMID:11350018

Laube, N; Jansen, B; Schneider, A; Steffes, H J; Hesse, A

2001-03-01

75

Omega3 Fatty Acids for Cardiovascular Disease Prevention  

Microsoft Academic Search

Opinion statement  Major dietary sources of omega-3 fatty acids are fish containing eicosapentaenoic acid (EPA) and docosahexaenoic acid (DHA),\\u000a as well as nuts, seeds, and vegetable oils containing ?-linolenic acid (ALA). Omega-3 fatty acids, especially those derived\\u000a from marine sources, may be a useful tool for the primary and secondary prevention of cardiovascular disease. Omega-3s exert\\u000a their cardioprotective effects through multiple

Andrew Paul DeFilippis; Michael J. Blaha; Terry A. Jacobson

2010-01-01

76

In vitro analysis of binding capacities of calcium to phytic acid in different food samples  

Microsoft Academic Search

The present work was performed to study the role which plays phytic acid in calcium binding, and to determine the calcium binding capacities in different foods, using in vitro extractions. Different food samples (soybeans, oats, chickpea, rice flour, and corn semolina) were extracted for 4 h at 37 °C using artificial simulated gastrointestinal juice (pepsin) at pH=2. The total calcium and phytic

Ferial Dendougui; Georg Schwedt

2004-01-01

77

The role of calcium in the prevention of cardiovascular disease-a review of observational studies and randomized clinical trials.  

PubMed

Calcium is a mineral that is important for bone health and has also been suggested to play a role in the prevention of cardiovascular disease (CVD). Lately, the potential effects of both inadequate and excessive calcium intake have received growing attention. In this review, we summarize the evidence from experimental, epidemiologic, and clinical studies investigating the role of calcium intake, either from the diet or from supplements, as well as blood concentrations, in relation to the risk of CVD in adults. In vitro and in vivo laboratory studies suggest that calcium may be involved in CVD development through multiple pathways, including blood cholesterol, insulin secretion and sensitivity, vasodilation, inflammatory profile, thrombosis, obesity, and vascular calcification. Several prospective epidemiologic studies have examined how dietary or supplemental calcium intake is associated with CVD incidence or mortality in middle-aged and older adults, and the results are inconsistent. Prospective studies investigating blood concentrations of calcium have also reported mixed results. However, changes in blood calcium concentrations may reflect a disturbed calcium phosphate balance, which is associated with increased risk of CVD. To date there is no randomized clinical trial that has been designed specifically to test the effect of calcium supplementation on the risk of CVD as the primary end point. Existing trials have performed secondary analyses, and most of them have been conducted among postmenopausal women. These trials suggest that calcium supplementation has no effect on CVD development; however, they do not allow a definitive conclusion to be drawn. The average daily intake of calcium is low in many populations; however, the evidence for a potential role of dietary or supplemental calcium in the prevention of CVD remains insufficient and inconclusive. Only large-scale randomized trials designed to investigate the effects of calcium supplementation on CVD events as the primary end point, as well as short-term trials investigating the effect on coronary biomarkers, can provide a definitive answer. PMID:24022513

Rautiainen, Susanne; Wang, Lu; Manson, Joann E; Sesso, Howard D

2013-11-01

78

Reduced Urinary Calcium on a Vegetarian Diet May Reflect Reduced Calcium Absorption With Phytic Acid, Not Calcium Conservation With Less Meat Protein  

Microsoft Academic Search

LEARNING OUTCOME: To consider phytic acid, not just meat protein, as a dietary variable that influences urinary calcium excretion in vegetarians.Dietary protein, especially meat protein, is frequently cited as a risk factor for osteoporosis. Although protein from purified sources is calciuretic, protein from meat is not (Spencer, et al., Am J Clin Nutr 31: 2167, 1978; Hunt, et al., Am

J. R. Hunt

1997-01-01

79

Calcium channel blocker prevents stress-induced activation of renin and aldosterone in conscious pig  

SciTech Connect

A considerable amount of data suggest the involvement of calcium-mediated processes in the activation of the renin-angiotensin-aldosterone (RAA) cascade. To investigate the effect of calcium-channel inhibition on the RAA system, the authors studied 21 conscious pigs. Blood renin and aldosterone levels increased by subjecting animals to 24 hours of immobilization stress. Renin and aldosterone levels were repeatedly measured by radioimmunoassay in blood samples taken periodically over 24 hours from a chronically implanted arterial cannula. Pretreatment of the animals (N = 11) with nisoldipine, 2 {times} 20 mg p.o. daily for 2 days before and on the day of immobilization, transiently attenuated the stress-induced increase of plasma renin activity and completely prevented the rise of aldosterone, as compared to nontreated controls (N = 10). The finding that nisoldipine suppresses RAA activation induced by a nonpharmacologic stimulus in the conscious intact animal may have clinical implications.

Ceremuzynski, L.K.; Klos, J.; Barcikowski, B.; Herbaczynska-Cedro, K. (Department of Cardiology, Postgraduate Medical School, Warsaw (Poland))

1991-06-01

80

A new CO 2 disposal process via artificial weathering of calcium silicate accelerated by acetic acid  

Microsoft Academic Search

A new disposal process for anthropogenic CO2 via an artificially accelerated weathering reaction is proposed to counteract global warming. The process is essentially composed of the following two steps:(1)CaSiO3+2CH3COOH?Ca2++2CH3COO?+H2O+SiO2(2)Ca2++2CH3COO?+CO2+H2O?CaCO3?+2CH3COOHStep (1) is the extraction of calcium ions by acetic acid from calcium silicate, for example, wollastonite rocks. Step (2) is the deposition of calcium carbonate from the solution of calcium ions

M. Kakizawa; A. Yamasaki; Y. Yanagisawa

2001-01-01

81

Complex forming properties of natural organic acids. Pt. 2. Complexes with iron and calcium.  

National Technical Information Service (NTIS)

An ultrafiltration technique combined with ion-selective-electrode and atomic absorption methods have been employed to obtain information on the complex forming properties of fulvic acid with iron and calcium. A model for interpreting complexation of meta...

J. H. Ephraim A. S. Mathuthu J. A. Marinsky

1990-01-01

82

Polycarboxylic acids containing acetal functions: calcium sequestering compounds based on oxidized carbohydrates  

Microsoft Academic Search

A number of polycarboxylic acids containing acetal functions have been prepared by a two-step oxidation of carbohydrates.\\u000a Their calcium sequestering behavior is compared with that of a series of model polycarboxylic acids. It is found that calcium\\u000a sequestration by oxidized carbohydrates is less than that by corresponding ether polycarboxylates, since (a) acetal oxygens\\u000a have a lower coordinating power than ether

M. S. Nieuwenhuizen; A. P. G. Kieboom; H. van Bekkum

1983-01-01

83

Impaired lipid metabolism in calcium oxalate stone forming rats and DL ? - lipoic acid supplementation  

Microsoft Academic Search

Oxalate, the major renal stone forming constituent, from dietary sources like - spinach, rhubarb, strawberries, tea etc., has been reported to induce lipid peroxidation and alter the lipid profiles. Physiological availability or biosynthesis of DL ?-lipoic acid, a shadow nutrient, from arachidonic acid is diminished when health is impaired. DL ?-lipoic acid has been reported to counteract calcium oxalate crsytallisation

R. Sumathi; S. Jayanthi; P. Varalakshmi

1995-01-01

84

Role of calcium and vitamin D in the prevention and the treatment of postmenopausal osteoporosis: An overview  

Microsoft Academic Search

Summary When discussing the use of calcium and vitamin D in the prevention and the treatment of osteoporosis one can make a distinction between the use as dietary supplementation to correct or prevent deficiencies, and the pharmacologic use of higher doses, whether or not in association with other drugs. However, in practical terms it is not always possible to clearly

J. M. Kaufman

1995-01-01

85

Effect of Fatty Acids or Calcium Soaps on Rumen and Total Nutrient Digestibility of Dairy Rations1  

Microsoft Academic Search

Two trials ascertained whether feeding fatty acids as preformed calcium soaps would permit normal digestibility of fiber without reducing availabilities of fatty acids or energy. Six diets contained no added fat (control) or the equivalent of 4.5% added fatty acids as tallow or soy fatty acids, tallow or soy calcium soaps, or tallow combined with the nonnutritive carrier verxite. Six

T. C. Jenkins; D. L. Palmquist

1984-01-01

86

Prevention of volatile fatty acids production and limitation of odours from winery wastewaters by denitrification.  

PubMed

The effect of the addition of nitrate to winery wastewaters to control the formation of VFA in order to prevent odours during storage and treatment was studied in batch bioreactors at different NO(3)/chemical oxygen demand (COD) ratios and at full scale in natural evaporation ponds (2 x 7000 m(2)) by measuring olfactory intensity. In the absence of nitrate, butyric acid (2304 mgL(-1)), acetic acid (1633 mgL(-1)), propionic acid (1558 mgL(-1)), caproic acid (499 mgL(-1)) and valeric acid (298 mgL(-1)) were produced from reconstituted winery wastewater. For a ratio of NO(3)/COD=0.4 gg(-1), caproic and valeric acids were not formed. The production of butyric and propionic acids was reduced by 93.3% and 72.5%, respectively, at a ratio of NO(3)/COD=0.8, and by 97.4% and 100% at a ratio of NO(3)/COD=1.2 gg(-1). Nitrate delayed and decreased butyric acid formation in relation to the oxidoreduction potential. Studies in ponds showed that the addition of concentrated calcium nitrate (NITCAL) to winery wastewaters (3526 m(3)) in a ratio of NO(3)/COD=0.8 inhibited VFA production, with COD elimination (94%) and total nitrate degradation, and no final nitrite accumulation. On the contrary, in ponds not treated with nitrate, malodorous VFA (from propionic to heptanoïc acids) represented up to 60% of the COD. Olfactory intensity measurements in relation to the butanol scale of VFA solutions and the ponds revealed the pervasive role of VFA in the odour of the untreated pond as well as the clear decrease in the intensity and not unpleasant odour of the winery wastewater pond enriched in nitrates. The results obtained at full scale underscored the feasibility and safety of the calcium nitrate treatment as opposed to concentrated nitric acid. PMID:17467770

Bories, André; Guillot, Jean-Michel; Sire, Yannick; Couderc, Marie; Lemaire, Sophie-Andréa; Kreim, Virginie; Roux, Jean-Claude

2007-04-30

87

The dihydropyridine calcium channel blocker benidipine prevents lysophosphatidylcholine-induced endothelial dysfunction in rat aorta  

PubMed Central

Background Lysophosphatidylcholine (LPC), an atherogenic component of oxidized low-density lipoprotein, has been shown to induce the attenuation of endothelium-dependent vascular relaxation. Although benidipine, a dihydropyridine-calcium channel blocker, is known to have endothelial protective effects, the effects of benidipine on LPC-induced endothelial dysfunction remain unknown. We examined the effects of benidipine on the impairment of endothelium-dependent relaxation induced by LPC. Methods Benidipine was administered orally to rats and aortas were then isolated. Aortic rings were treated with LPC and endothelial functions were then evaluated. Additionally, the effects of benidipine on intracellular calcium concentration ([Ca2+]i) and membrane fluidity altered by LPC in primary cultured rat aortic endothelial cells were examined. [Ca2+]i was measured using the fluorescent calcium indicator fura-2. Membrane fluidity was monitored by measuring fluorescence recovery after photobleaching. Results Treatment with LPC impaired endothelial function. Benidipine prevents the impairment of relaxation induced by LPC. Acetylcholine elicited an increase in [Ca2+]i in fura-2 loaded endothelial cells. The increase in [Ca2+]i was suppressed after exposure to LPC. Plasma membrane fluidity increased following incubation with LPC. Benidipine inhibited the LPC-induced increase in membrane fluidity and impairment of increase in [Ca2+]i. Conclusion These results suggest that benidipine inhibited LPC-induced endothelial dysfunction by maintaining increase in [Ca2+]i. Benidipine possesses membrane stabilization properties in LPC-treated endothelial cells. It is speculated that the preservation of membrane fluidity by benidipine may play a role in the retainment of calcium mobilization. The present findings may provide new insights into the endothelial protective effects of benidipine.

Takayama, Makoto; Yao, Kozo; Wada, Michihito

2009-01-01

88

Effects of calcium channel blockers on gastric emptying and acid secretion of the rat in vivo.  

PubMed Central

Experiments were designed to evaluate the effects of three calcium channel blockers (verapamil, diltiazem and cinnarizine) on gastric emptying and secretion in the rat. Pretreatment with the calcium blockers delayed gastric emptying of phenol red in a dose-dependent manner. Verapamil was the most effective of the agents tested. Verapamil and diltiazem inhibited gastric acid secretion in the pylorus-ligated rat without affecting pepsin output. Cinnarizine was ineffective in this model. When the perfused lumen of the anaesthetized rat was used, verapamil was found to inhibit responses to carbachol or histamine more than those to pentagastrin. Further, we found a greater sensitivity to verapamil for basal compared with vagal-stimulated (2-deoxy-D-glucose) acid secretion. Neither diltiazem nor cinnarizine modified gastric acid secretion in this experimental model. These findings are discussed in relation to the role of extracellular calcium in gastric motility and secretion, and the existence of a regional and functional selectivity for calcium blockers is proposed.

Brage, R.; Cortijo, J.; Esplugues, J.; Esplugues, J. V.; Marti-Bonmati, E.; Rodriguez, C.

1986-01-01

89

Urinary calcium and uric acid excretion in children with vesicoureteral reflux.  

PubMed

Urolithiasis is relatively common in children, and identifiable predisposing factors for stone formation, including metabolic and structural derangements, can be established in most cases. Vesicoureteral reflux (VUR) is a common cause of kidney stone formation. The pathophysiological mechanism of urolithiasis in reflux is related to urinary tract infection and urinary stasis, both of which promote urinary crystal formation, but metabolic causes, such as crystallurias (mostly hypercalciuria), may also be involved in this process. However, few studies on urinary calcium and uric acid excretion in children with VUR have been conducted. We have studied the frequency of hypercalciuria and hyperuricosuria in children with VUR and compared the results with those from a control group. The VUR group comprised 108 children with VUR (19 boys, 89 girls; age range 3 months to 12 years), and the control group comprised 110 healthy children without any history of reflux or urinary tract infection (30 boys, 80 girls; age range 2 months to 12 years). Fasting urine was analyzed for the calcium/creatinine (Ca/Cr) and uric acid/creatinine (UA/Cr) ratios. Hypercalciuria was more frequently diagnosed in the VUR patients than in the control group (21.3 vs. 3.6%; P?=?0.0001). Significant differences between the two groups were also found for the mean Ca/Cr and UA/Cr ratios (P?=?0.0001 and P?=?0.0001, respectively). No differences were found in the urinary Ca/Cr or UA/Cr ratios related to VUR grading or unilateral/bilateral VUR in the patient group, with the exception of those for hypercalciuria and mild VUR (P?=?0.03). The association of urinary stones and microlithiasis in the VUR group was 29.6%. Our results demonstrate that the frequency of hypercalciuria and hyperuricosuria was higher in pediatric patients with VUR than in healthy children. Knowing this relationship, preventive and therapeutic interventions for stone formation in VUR could be greatly expanded. PMID:21814729

Madani, Abbas; Kermani, Nooshin; Ataei, Neamatollah; Esfahani, Seyed Taher; Hajizadeh, Niloufar; Khazaeipour, Zahra; Rafiei, Sima

2011-08-04

90

Prevention of acid drainage from coal refuse  

Microsoft Academic Search

It has been demonstrated by the US Bureau of Mines, academia, and others that the abundance of acid drainage that flows from pyritic coal refuse, pyrite-bearing coal, and pyritic overburden is associated with the surface activity of this pyritic material and an iron-oxidizing bacterium, Thiobacillus ferrooxidans. More recently, it has been demonstrated that certain chemical compounds can affect this surface

Stancel

1982-01-01

91

Oleanolic acid induces relaxation and calcium-independent release of endothelium-derived nitric oxide  

PubMed Central

Background and purpose: The present study investigated the mechanisms by which oleanolic acid, a component of olive oil, increases release of nitric oxide (NO). Experimental approach: Measurements of isometric tension, NO concentration, or endothelial cell calcium were made in rat isolated mesenteric arteries. Immunoblotting for endothelial NOS (eNOS) and Akt kinase were performed in primary cultures of human umbilical vein endothelial cells (HUVECs). Key results: Oleanolic acid (3–30??M) evoked endothelium-dependent relaxations in noradrenaline-contracted rat superior and small mesenteric arteries. In rat superior mesenteric arteries, oleanolic acid induced simultaneous increases in NO concentration and relaxation, and these responses were inhibited by an inhibitor of NOS, asymmetric dimethyl-L-arginine (300??M) and by the NO scavenger, oxyhaemoglobin (10??M). Oleanolic acid-evoked NO increases were not reduced in Ca2+-free solution and in the presence of an inhibitor of endoplasmic reticulum calcium-ATPase, thapsigargin (1??M). Oleanolic acid evoked relaxation without changes in endothelial cell calcium, but decreased smooth muscle calcium in arterial segments. Oleanolic acid failed to increase calcium in HUVECs, but increased time-dependently phosphorylation of Akt kinase at Serine473 (Akt-Ser473) and eNOS at Serine1177 (eNOS-Ser1177), which was attenuated by inhibitors of phosphoinositide-3-kinase. Conclusions and implications: This study provides direct evidence that a component of olive oil, oleanolic acid, activated endothelium-dependent release of NO and decreased smooth muscle cell calcium followed by relaxation. The oleanolic acid-evoked endothelium-derived NO release was independent of endothelial cell calcium and involved phosphoinositide-3-kinase-dependent phosphorylation of Akt-Ser473 followed by phosphorylation of eNOS-Ser1177.

Rodriguez-Rodriguez, R; Stankevicius, E; Herrera, M D; ?stergaard, L; Andersen, M R; Ruiz-Gutierrez, V; Simonsen, U

2008-01-01

92

A Randomized Trial of Low-Animal-Protein or High-Fiber Diets for Secondary Prevention of Calcium Nephrolithiasis  

Microsoft Academic Search

Background: The purpose of this trial was to evaluate the efficacy of a low-animal-protein diet (LAPD) or a high-fiber diet (HFD) for the prevention of calcium nephrolithiasis recurrence. Methods: We conducted a 4-year randomized trial comparing the effect of 2 diets in 175 idiopathic calcium stone formers. Fifty-five were assigned to a LAPD (<13% of total energy derived from protein),

Bertrand Dussol; Cecilia Iovanna; Michel Rotily; Sophie Morange; Françoise Leonetti; Patricia Dupuy; Alain Vazi; Adriana Saveanu; Anderson Loundou; Yvon Berland

2008-01-01

93

Inhibition of calcium influx and calcium current by gamma-aminobutyric acid in single synaptic terminals.  

PubMed Central

Inhibition of Ca influx and Ca current by gamma-aminobutyric acid (GABA) was studied in single synaptic terminals of isolated retinal bipolar neurons. Measurements of intracellular Ca concentration [( Ca]i) using the fluorescent Ca indicator fura-2 showed that GABA potently inhibited Ca influx into the terminal elicited by high extracellular K concentration ([K]o). This inhibition was attributed to GABA type A (GABAA) receptor-activated chloride ion conductance that prevented bipolar neurons from depolarizing sufficiently to activate the Ca current, even in response to increased [K]o. Patch-clamp recordings of the Ca current revealed a second effect of GABA: GTP-dependent inhibition of the Ca current. This inhibition was not mediated by GABAA receptors, but baclofen, which binds to the GABA type B (GABAB) receptor and is known to inhibit the Ca current in other systems, was not able to mimic the action of GABA. This suggests the involvement of a different type of GABAB-like receptor in the inhibition of Ca current by GABA. GABA did not cause an overall suppression of the Ca current; rather, the voltage-dependence of Ca-channel activation was shifted to more depolarized potentials. Thus, maximal inhibition of the Ca current by GABA occurred in the physiological range of potential. Images

Heidelberger, R; Matthews, G

1991-01-01

94

Calcium- and hydroxyapatite-binding properties of glucuronic acid-rich and iduronic acid-rich glycosaminoglycans and proteoglycans.  

PubMed

This study describes the interaction of a small chondroitin sulphate proteoglycan and the glycosaminoglycans chondroitin 4-sulphate, dermatan sulphate and heparan sulphate with hydroxyapatite. All macromolecules possessed a high affinity, with the iduronic acid-rich dermatan sulphate and heparan sulphate displaying higher adsorption maxima than the glucuronic acid-rich chondroitin 4-sulphate. At similar concentrations, dermatan sulphate produced a 30% inhibition of hydroxyapatite-induced crystal growth, whilst chondroitin 4-sulphate yielded 50% inhibition. Estimation of the calcium binding capacity of these glycosaminoglycans using equilibrium dialysis indicated that chondroitin 4-sulphate bound five times more calcium than dermatan sulphate at a calcium concentration similar to that of serum. The data indicate a possible important role for chondroitin 4-sulphate in dentinogenesis where it is the dominant glycosaminoglycan, since it could act as a capture point for calcium ions during mineralisation, with the leucine-rich domain of its parent proteoglycan acting as anchor points to type I collagen. PMID:9541236

Embery, G; Rees, S; Hall, R; Rose, K; Waddington, R; Shellis, P

1998-01-01

95

Fluorescence Measurement of Changes in Intracellular Calcium Induced by Excitatory Amino Acids in Cultured Cortical Astrocytes  

Microsoft Academic Search

Population response of (Ca*+), in cultured cortical astrocytes to excitatory amino acids was measured at room tempera- ture using the calcium-sensitive dye fura-2. Quisqualic acid (QA), glutamate (Glu), and kainic acid (KA) caused a peak increase in (Caz+), in the order QA > Glu > KA. No response to N-methyl-o-aspartic acid (NMDA) was observed whether or not Mg2+ was present

A. M. Jensen; S. Y. Chiul

1990-01-01

96

Fabrication of calcium phosphate-calcium sulfate injectable bone substitute using hydroxy-propyl-methyl-cellulose and citric acid.  

PubMed

In this study, an injectable bone substitute (IBS) consisting of citric acid, chitosan, and hydroxyl propyl methyl cellulose (HPMC) as the liquid phase and tetra calcium phosphate (TTCP), dicalcium phosphate dihydrate (DCPD) and calcium sulfate dehydrate (CSD, CaSO4 x 2H2O) powders as the solid phase, were fabricated. Two groups were classified based on the percent of citric acid in the liquid phase (20, 40 wt%). In each groups, the HPMC percentage was 0, 2, and 4 wt%. An increase in compressive strength due to changes in morphology was confirmed by scanning electron microscopy images. A good conversion rate of HAp at 20% citric acid was observed in the XRD profiles. In addition, HPMC was not obviously affected by apatite formation. However, both HPMC and citric acid increased the compressive strength of IBS. The maximum compressive strength for IBS was with 40% citric acid and 4% HPMC after 14 days of incubation in 100% humidity at 37 degrees C. PMID:20333539

Thai, Van Viet; Lee, Byong-Taek

2010-03-24

97

Effects of Calcium on the Erosive Potential of Acidic Candies in Saliva  

Microsoft Academic Search

Theoretical calculations have shown that acidic candies may be potentially erosive upon consumption. However, little is known about the protective effect of adding calcium to potentially erosive candies and about the protective effects of saliva that cannot be fully accounted for by theoretical calculations. Therefore, the aims of this study were to (1) determine the erosive potential of acidic candies

T. Jensdottir; B. Nauntofte; C. Buchwald; A. Bardow

2007-01-01

98

Location and nature of calcium-binding sites in salivary acidic proline-rich phosphoproteins  

SciTech Connect

The location of the calcium-binding sites in the human acidic proline-rich proteins, salivary proteins A and C, was determined by equilibrium dialysis of the tryptic peptides with buffers containing /sup 45/Ca. All the calcium-binding sites are located in the NH/sub 2/-terminal tryptic peptide (TX peptide). The nature of the calcium binding sites in the TX peptide and native salivary proteins A and C, as well as dephosphorylated proteins was compared. Two types of sites can be distinguished in peptide TX. Type I sites have an apparent dissociation constant (K) of 38 ..mu..M and are responsible for the binding of 2.6 mol of Ca/mol of peptide. The corresponding figures for Type II sites are 780 ..mu..M and 5.3 mol of Ca/mol of peptide. In the native proteins, the amount of calcium bound at the type II sites decreases to 3.9 mol of Ca/mol of proteins A and C and K increases to 1100 ..mu..M. The amount of calcium bound at type I sites decreases to 1.5 mol/mol of protein A and 0.6 mol/mol of protein C, but there is no change in K. Dephosphorylation affects the calcium binding at both types of sites. The experiments indicate that the COOH-terminal parts of the native proteins affect the number and the nature of the protein calcium-binding sites. Proton and phosphorous NMR data demonstrate that ..beta..-COOH in aspartic acid, as well as phosphoserine, are part of the calcium-binding sites. The difference in calcium binding to salivary proteins A and C may be due at least partially to differences in the environment of one or more aspartic acids.

Bennick, A. (Univ. of Toronto, Ontario); McLaughlin, A.C.; Grey, A.A.; Madapallimattam, G.

1981-05-25

99

Amino acid residues outside of the pore region contribute to N-type calcium channel permeation.  

PubMed

It is widely believed that the selectivity of voltage-dependent calcium channels is mainly controlled by amino acid residues contained within four p-loop motifs forming the pore of the channel. An examination of the amino acid sequences of high voltage-activated calcium channels reveals that their domain III S5-H5 regions contain a highly conserved motif with homology to known EF hand calcium binding proteins, hinting that this region may contribute to channel permeation. To test this hypothesis, we used site-directed mutagenesis to replace three conserved negatively charged residues in the N-type calcium channel alpha1B subunit (Glu-1321, Asp-1323, and Glu-1332) with positively charged amino acids (lysine and arginine) and studied their effect on ion selectivity using whole cell and single channel patch clamp recordings. Whereas the wild type channels conducted barium much more effectively than calcium, the mutant displayed nearly equal permeabilities for these two ions. Individual replacement of residue 1332 or a double substitution of residues 1321 and 1323 with lysine and arginine, respectively, were equally effective. Disruption of the putative EF hand motif through replacement of the central glycine residue (1326) with proline resulted in a similar effect, indicating that the responses observed with the triple mutant were not due to changes in the net charge of the channel. Overall, our data indicate that residues outside of the narrow region of the pore have the propensity to contribute to calcium channel permeation. They also raise the possibility that interactions of calcium ions with a putative calcium binding domain at the extracellular side of the channel may underlie the differential permeabilities of the channel for barium and calcium ions. PMID:11120735

Feng, Z P; Hamid, J; Doering, C; Jarvis, S E; Bosey, G M; Bourinet, E; Snutch, T P; Zamponi, G W

2000-12-18

100

[Chemical structure of dicarboxylic acids and their capacity inhibiting of calcium oxalate crystal growth].  

PubMed

The effect of dicarboxylic acids with a three C-C bonds distance on the crystallization of calcium oxalate (CaOxa) was investigated in silica gel system by means of X-ray diffraction (XRD), Fourier transform infrared (FTIR) spectroscopy, and scanning electron microscopy (SEM). These acids include succinic acid, maleic acid, fumaric acid, malic acid, L-aspartic acid and tartaric acid. All the dicarboxylic acids can inhibit the aggregation of calcium oxalate monohydrate (COM) and induce the formation of calcium oxalate dehydrate (COD). But their ability to inhibit the growth and aggregation of COM, to diminish the specific surface area of COM and to induce COD formation were strengthened as the number of the substituted hydroxyl or amino group increased. The molecular mechanisms were discussed in terms of chemical structures of dicarboxylic acids. Only the dicarboxylic acids with a HOOC-CH(R)-CH2-COOH (R=OH or NH2) group were found to have the best inhibitory effect on the CaOxa urinary stones. The results could provide some clue to looking for new drugs for urinary stones in clinic. PMID:18306777

Deng, Sui-ping; Hu, Peng; Ouyang, Jian-ming

2007-10-01

101

ROLE OF INTRACELLULAR CALCIUM AND PHOSPHOLIPASE A2 IN ARACHIDONIC ACID-INDUCED TOXICITY IN LIVER CELLS OVEREXPRESSING CYP2E1*  

PubMed Central

Liver cells (HepG2 and primary hepatocytes) overexpressing CYP2E1 and exposed to arachidonic acid (AA) were previously shown to lose viability together with enhanced lipid peroxidation. These events were blocked in cells pre-incubated with antioxidants (? -tocopherol, glutathione ethyl ester), or in HepG2 cells not expressing CYP2E1. The goal of the current study was to evaluate the role of calcium and calcium-activated hydrolases in these CYP2E1-AA interactions. CYP2E1-expressing HepG2 cells treated with AA showed an early increase in cytosolic calcium and partial depletion of ionomycin-sensitive calcium stores. These changes in calcium were blocked by ? -tocopherol. AA activated phospholipase A2 (PLA2) in CYP2E1-expressing liver cells, and this was inhibited by PLA2 inhibitors or ? -tocopherol. PLA2 inhibitors prevented the cell death caused by AA, without affecting CYP2E1 activity or lipid peroxidation. AA toxicity and PLA2 activation were inhibited in calcium-depleted cells, but not by removal of extracellular calcium alone. Removal of extracellular calcium inhibited the early increase in cytosolic calcium caused by AA. CYP2E1 overexpressing HepG2 cells exposed to AA showed a decrease in mitochondrial membrane potential, which was prevented by the PLA2 inhibitors. These results suggest that AA-induced toxicity to CYPE1-expressing cells: (i) is associated with release of Ca2+ from intracellular stores that depends mainly on oxidative membrane damage; (ii) is associated with activation of PLA2 that depends on intracellular calcium and lipid peroxidation; iii) does not depend on increased influx of extracellular calcium, and iv) depends on the effect of converging events (lipid peroxidation, intracellular calcium, activation of PLA2) on mitochondria to induce bioenergetic failure and necrosis. These interactions may play a role in alcohol liver toxicity, which requires polyunsaturated fatty acids, and involves induction of CYP2E1.

Caro, Andres A.; Cederbaum, Arthur I.

2007-01-01

102

Role of boric acid in synthesis and tailoring the properties of calcium aluminate phosphor  

Microsoft Academic Search

In the present work related to the development of high-luminous blue-emitting calcium aluminate phosphor, the active role of boric acid (H3BO3) as a chemical additive is identified. The appropriate usage of H3BO3 in defining the crystal structure, morphology and momentous variation in luminescent properties of calcium aluminate long persisting (LP) phosphor is systematically studied and presented. The results attribute two

D. Haranath; Pooja Sharma; Harish Chander; Anwar Ali; Nitesh Bhalla; S. K. Halder

2007-01-01

103

Effect of Protein and Amino Acid Levels on Bone Formation in Diets Varying in Calcium Content  

Microsoft Academic Search

The effect of different dietary levels of amino acids, calcium and phosphorus as influenced by phytase supplementation was evaluated in broiler chickens. The experimental design consisted of a 3 x 4 x 2 factorial arrangement with three levels of digestible lysine (1.10, 1.30 and 1.50%), four levels of calcium (0.50, 0.70, 0.90 and 1.1%) and diets containing 0.35% AP with

S. Cerrate; F. Perazzo; A. Abdel-Maks; F. Yan

2009-01-01

104

Templating route for mesostructured calcium phosphates with carboxylic acid- and amine-type surfactants.  

PubMed

Mesostructured calcium phosphates constructed by ionic frameworks were synthesized using carboxylic acid- and amine-type surfactants in mixed solvent systems of ethanol and water. A lamellar mesostructured calcium phosphate was prepared using palmitic acid as an anionic surfactant, as in the case using n-alkylamines. A wormhole-like mesostructured calcium phosphate can be obtained using dicarboxyl N-lauroyl- l-glutamic acid, whose headgroup is larger than that of palmitic acid. Similar mesostructured product was obtained using 4-dodecyldiethylenetriamine with a large headgroup containing two primary amine groups. Interactions of carboxyl and primary amino groups in the surfactant molecules with inorganic species are quite important for the formation of mesostructured calcium phosphates. The Ca/P molar ratio of mesostructured calcium phosphates was strongly affected by the molecular structure of surfactants containing carboxyl and primary amino groups. Ca-rich materials can be obtained using carboxylic acid-type surfactants (Ca/P approximately 1.7) rather than amine-type surfactants (Ca/P approximately 1.0). PMID:18947246

Ikawa, Nobuaki; Hori, Hideki; Kimura, Tatsuo; Oumi, Yasunori; Sano, Tsuneji

2008-10-24

105

Amino acid transport into cultured tobacco cells. II. Effect of calcium  

SciTech Connect

The effects of calcium ions on lysine transport into cultured Wisconsin-38 tobacco cells were examined. In the presence of calcium, lysine was transported at a relatively low rate for 30 to 40 minutes followed by a period of increasing rates and subsequent stabilization at a higher rate after 2 to 3 hours. In the absence of calcium, transport was uniformly low. Time-dependent stimulation of lysine transport rate was observed after the cells had been preincubated in calcium-containing media. Similar treatments also resulted in the stimulated uptake of a variety of other amino acids, organic compounds, and sulfate. The stimulation of lysine uptake was apparently not due to nutrient starvation. Lysine transport was not stimulated in a time-dependent fashion by K/sup +/, La/sup 3 +/, Mg/sup 2 +/, or Mn/sup 2 +/. Cells with stimulated transport rates continued to exhibit high rates when washed with calcium-containing media followed by transport in calcium-containing media. All other cation wash treatments were inhibitory, although magnesium treatments resulted in partial preservation of stimulated transport rates. Cycloheximide inhibited the calcium/time-dependent stimulation of lysine transport and caused the stimulated rate to decay. The initial experimental treatments or the culture conditions may represent some form of shock that alters the membrane transport mechanism, thus reducing transport. The observed calcium/time-dependent stimulation may require protein synthesis and represents damage repair.

Harrington, H.M.; Berry, S.L.; Henke, R.R.

1981-02-01

106

Oleanolic acid prevents glucocorticoid-induced hypertension in rats.  

PubMed

The present study was designed to evaluate the antihypertensive activity of oleanolic acid isolated from Viscum articulatum, Burm. (Loranthaceae) in glucocorticoid (dexamethasone)-induced hypertension in rats and to propose a probable mechanism of action for this effect. Male Wistar rats (300-350?g) received dexamethasone (20??g/kg/day?s.c.) or saline (vehicle) for 10?days. In a prevention study, the rats received oleanolic acid (60?mg/kg i.p.) for 5?days, followed by dexamethasone or saline for 10?days. During this period the systolic blood pressure and body weight were evaluated on alternate days. At the end of the experiment, the weight of the thymus gland, plasma nitrate/nitrite (nitric oxide metabolites) concentration and cardiac lipid peroxidation value were determined. Oleanolic acid (60?mg/kg i.p.) significantly prevented a rise in the systolic blood pressure and cardiac lipid peroxidation level after administration of dexamethasone (p?prevented significantly in the group treated with oleanolic acid (p?acid (60?mg/kg i.p.) prevents dexamethasone-induced hypertension in rats, which may be attributed to its antioxidant and nitric oxide releasing action. PMID:21953707

Bachhav, Sagar S; Patil, Savita D; Bhutada, Mukesh S; Surana, Sanjay J

2011-02-24

107

Prevention of occupational allergy caused by exposure to acid anhydrides.  

PubMed

This paper focuses on the prevention of IgE-mediated symptoms of the eyes and airways caused by exposure to acid anhydrides in the workplace. Acid anhydrides are widely used in the production of alkyd resins and as curing agents for epoxy resins. Heavy exposure to acid anhydrides causes severe irritation. However, reports of direct irritation of mucous membranes or skin are rare in recent years, since a package of multiple engineering controls has been introduced to reduce exposure. On the other hand, acid anhydrides are well-known industrial inhalant sensitizers and can cause occupational allergy even at very low exposure intensities. Therefore, safe use in industry demands both control of the level of exposure causing allergic diseases in the workshop and programmes for prevention of occupational allergy. PMID:10441899

Yokota, K; Takeshita, T; Morimoto, K

1999-07-01

108

Preoperative infusion of amino acids prevents postoperative hypothermia  

Microsoft Academic Search

Intraoperative infusion of amino acids has been found to stimulate energy expenditure and thereby prevent anaesthesia-induced hypothermia. Rectal temperature and respiratory gas exchange were measured in 24 female patients before and after isoflurane anaesthesia. Sixteen patients had an amino acid mixture of 240 kJ h 1 , infused over 1-2 h before anaesthesia and eight control patients received saline. We

E. SELLDÉN; R. BRÄNSTRÖM; T. BRUNDIN

109

Loading of amphipathic weak acids into liposomes in response to transmembrane calcium acetate gradients  

Microsoft Academic Search

We describe a novel procedure to load amphipathic weak acid molecules into preformed liposomes. Differences in calcium acetate concentrations across the liposomal membrane induce an increase of the internal pH. This pH imbalance serves as an efficient driving force to load and accumulate weak acids (5(6)-carboxyfluorescein and nalidixic acid) inside the lipid vesicles. The mechanism of loading and the relevance

Stéphane Clerc; Yechezkel Barenholz

1995-01-01

110

Mechanism of cytoplasmic calcium changes in platelets in contact with polystyrene and poly(acrylamide-co-methacrylic acid) surfaces  

Microsoft Academic Search

Changes in cytoplasmic free calcium levels ([Ca]i) in platelets in contact with polystyrene (PSt) and poly(acrylamide-co-methacrylic acid) (PAAmMAc) particles were evaluated and results were compared with those from two representative biological calcium agonists; thrombin and calcium ionophore A23187. PSt particles stimulated a steep increase in cytoplasmic calcium levels in platelets as much as thrombin and A23187. Serratia protease-treated platelets showed

Nobuhiko Yui; Ken Suzuki; Teruo Okano; Yasuhisa Sakurai; Chikako Ishikawa; Keiji Fujimoto; Haruma Kawaguchi

1993-01-01

111

A Quantitative Study of Calcium Binding by Isolated Streptococcal Cell Walls and Lipoteichoic Acid: Comparison with Whole Cells  

Microsoft Academic Search

Calcium-binding by surface components of oral bacteria may have important effects on remineralization\\/demineralization phenomena and plaque cohesion. Additionally, some species export large quantities of lipoteichoic acid, possibly as a protective measure. Measurement of calcium-binding can facilitate prediction of how this will effectively buffer plaque fluid calcium concentration and affect these processes. Using equilibrium dialysis, we measured calcium-binding capacities and affinities

R. K. Rose; S. D. Hogg; R. P. Shellis

1994-01-01

112

Effects of calcium soaps of long-chain fatty acids on feedlot performance, carcass characteristics and ruminal metabolism of steers.  

PubMed

Two trials were conducted to determine the effects of calcium soaps of long-chain fatty acids (calcium soap) on feedlot performance, diet digestibility, carcass characteristics and ruminal metabolism of steers fed diets (85% concentrate:15% corn silage) containing 0, 2, 4 or 6% calcium soap. In Trial 1, increasing calcium soap decreased (P less than .05) DM, CP and gross energy intake but increased total fatty acid intake. Feed to gain ratio tended to improve with increased calcium soap; gross energy conversion was not affected (P greater than .05) by diet. Average daily gain and hot carcass weight decreased (P less than .05) with addition of calcium soap; other carcass characteristics were not affected (P greater than .05). Apparent digestibilities of DM, N, energy and ash were not affected (P greater than .05) by calcium soap. Neutral detergent fiber digestibility increased linearly (P less than .08) with increasing calcium soap, whereas digestibility of total fatty acids was affected quadratically (P less than .05); fatty acid digestibility was similar among 0, 2 and 4% calcium soap diets but decreased for the 6% calcium soap diet. In Trial 2, increased calcium soap did not affect (P greater than .05) ruminal VFA concentrations, pH or in sacco NDF disappearance of orchardgrass following 12, 24 and 48 h of incubation. Calcium soap increased (P less than .07) ruminal concentrations of calcium soap fatty acids at 1, 2, 4 and 8 h postfeeding. Calcium soap did not improve performance of feedlot cattle fed high-concentrate diets. Further, calcium soap did not affect ruminal fermentation and did not dissociate significantly even when ruminal pH was below 6 for extended periods of time. PMID:2401671

Ngidi, M E; Loerch, S C; Fluharty, F L; Palmquist, D L

1990-08-01

113

The Role of Polycarboxylic Acids in Calcium Phosphate Mineralization  

Microsoft Academic Search

The role of two polyelectrolytes, poly-L-glutamate and poly-L-aspartate, in the growth of calcium phosphate crystal phases, has been investigated at constant supersaturation. Both molecules are strong inhibitors of HAP growth when present in the solution phase but also act as hydroxyapatite and (octacalcium phosphate)-like crystal nucleators when adsorbed on germanium surfaces. The structure of the polymers in solution is presented

Achilles Tsortos; George H. Nancollas

2002-01-01

114

Calcium, vitamin D, dairy products, and risk of colorectal cancer in the Cancer Prevention Study II Nutrition Cohort (United States)  

Microsoft Academic Search

Objective: Calcium, vitamin D, and dairy product intake may reduce the risk of colorectal cancer. We therefore examined the association between these factors and risk of colorectal cancer in a large prospective cohort of United States men and women. Methods: Participants in the Cancer Prevention Study II Nutrition Cohort completed a detailed questionnaire on diet, medical history, and lifestyle in

Marjorie L. McCullough; Andrea S. Robertson; Carmen Rodriguez; Eric J. Jacobs; Ann Chao; Carolyn Jonas; Eugenia E. Calle; Walter C. Willett; Michael J. Thun

2003-01-01

115

The calcium sensing receptor modulates fluid reabsorption and acid secretion in the proximal tubule.  

PubMed

The proximal tubule uses a complex process of apical acid secretion and basolateral bicarbonate absorption to regulate both luminal acidification and fluid absorption. One of the primary regulators of apical acid secretion is the luminal sodium-hydrogen exchanger expressed along the apical membrane of the proximal tubule. Similarly, the calcium-sensing receptor (CaSR) is also located along the luminal membrane of the proximal tubule. Here we investigated the role of CaSR in proton secretion and fluid reabsorption in proximal tubules by modulating luminal calcium concentration, using both in vivo micropuncture in rats and in vitro perfused mouse proximal tubules. Using CaSR knockout mice and a calcimimetic agent, we found that increased proton secretion and fluid reabsorption were CaSR dependent. Activating CaSR by either raising the luminal calcium ion concentration or by the calcimimetic caused a concomitant increase in sodium-dependent proton extrusion and fluid reabsorption, whereas in proximal tubules isolated from CaSR knockout mice varying calcium ion concentration had no effect. Application of a calcimimetic in lower concentrations of calcium ion stimulated these processes in vitro and in vivo. Thus, in both rats and mice, increased luminal calcium concentration leads to enhanced fluid reabsorption in the proximal tubule, a process related to activation of CaSR. PMID:23615500

Capasso, Giovambattista; Geibel, Peter J; Damiano, Sara; Jaeger, Philippe; Richards, William G; Geibel, John P

2013-04-24

116

Modulation of Dihydropyridine-Sensitive Calcium Channels in Heart Cells by Fish Oil Fatty Acids  

Microsoft Academic Search

The highly unsaturated n - 3 fatty acids from fish oils, eicosapentaenoic acid [EPA; C20:5 (n - 3)] and docosahexaenoic acid [DHA; C22:6 (n - 3)], prevent the toxicity of high concentrations of the cardiac glycoside ouabain to isolated neonatal rat cardiac myocytes. Arachidonic acid [C20:4 (n - 6)] lacks such protective action. The protective effect of the n -

Haifa Hallaq; Thomas W. Smith; Alexander Leaf

1992-01-01

117

Effects of Intrathecally Administered Aminoglycoside Antibiotics, Calcium-Channel Blockers, Nickel and Calcium on Acetic Acid-Induced Writhing Test in Mice  

Microsoft Academic Search

1.Antinociceptive effects of intrathecally administered aminoglycoside antibiotics, calcium-channel blockers, nickel and calcium ions on the acetic acid–induced writhing test in mice were examined.2.Neomycin (0.5–20.0 ?g\\/mouse) gentamicin (5–40 ?g\\/mouse), nicardipine, diltiazem and verapamil (0.5–80.0 ?g\\/mouse) and calcium ions (0.02–1.0 ?mol\\/mouse) exerted a dose-dependent antinociceptive activity on the acetic acid–induced writhing test. Nickel ions ( 2.5, 5.0 and 10.0 ?mol\\/mouse) were found

Ahmet Do?rul; Özgür Ye?ilyurt

1998-01-01

118

Are the anti-arrhythmic effects of omega-3 fatty acids due to modulation of myocardial calcium handling?  

PubMed Central

Both animal and clinical studies have demonstrated that omega-3 fatty acids have anti-arrhythmic properties. It has been suggested that these anti-arrhythmic effects are due to modulation of the activity of various myocardial calcium handling proteins such as ryanodine receptor (RyR), L-type calcium current and sodium/calcium exchanger. In this article, we review all the data available on the effects of omega-3 fatty acids on ventricular myocardial calcium handling. In addition we highlight some unanswered questions and discuss possible therapeutic benefits of omega-3 fatty acids.

Sankaranarayanan, Rajiv; Venetucci, Luigi

2012-01-01

119

Study of the chemical mechanisms of the reaction of neutralization of calcium hydroxide by phosphoric acid  

NASA Astrophysics Data System (ADS)

Calcium phosphates reported in this study, are prepared following an acido-basic reaction between phosphoric acid and calcium hydroxide. These phosphates are the brushite, tricalcium phosphate, hydroxyapatite and oxygenated apatite. The follow-up of the reaction by infra-red spectroscopy of absorption showed that the alkaline pH of calcium hydroxide solution, favours the formation of carbonated apatite, at the start of the reaction. Following the addition of phosphoric acid, the pH becomes increasingly favourable to the formation of the desired phase. The insertion of molecular oxygen in the apatitic tunnel is carried out by the use of hydrogen peroxide. The molecular oxygen rate in the apatite is then determined by volumetric analysis.

Elgadi, M.; Mejdoubi, E.; Elansari, L. L.; Essaddek, A.; Abouricha, S.; Lamhamdi, A.

2005-03-01

120

Effects of Calcium Deficiency on Potato Sets in Acid Soils  

Microsoft Academic Search

DURING the War, when many poor upland areas and commons in Britain were ploughed up for crop production, potatoes were commonly planted as a first crop in view of their tolerance to acid soil conditions. Many failures, however, were experienced where the soils were very strongly acid, with pH values of the order of 4.0, and it was shown that

T. Wallace; E. J. Hewitt

1948-01-01

121

Excitatory amino acids and neurodegeneration: a hypothetical role of calcium precipitation  

Microsoft Academic Search

Activation of excitatory amino acid (EAA) receptors can induce neurodegeneration by two major mechanisms of excitotoxicity, one related to the influx of Na+, Cl? and water, and the other to the increase in intracellular calcium concentration ([Ca2+]i). Thus, acute microinjection of EAAs in several areas of the central nervous system (CNS) has been used to produce neurodegenerative models. We studied

M. J Rodr??guez; F Bernal; N Andrés; Y Malpesa; N Mahy

2000-01-01

122

Procedure for the study of acidic calcium phosphate precursor phases in enamel mineral formation  

Microsoft Academic Search

Summary Considerable evidence suggests that an acidic calcium phosphate, such as octacalcium phosphate (OCP) or brushite, is involved as a precursor in enamel and other hard tissue formation. Additionally, there is in vitro evidence suggesting that fluoride accelerates and magnesium inhibits the hydrolysis of OCP to hydroxyapatite (OHAp). As the amount of OCP or brushite in enamel cannot be measured

C. Siew; S. E. Gruninger; L. C. Chow; W. E. Brown

1992-01-01

123

IMPLICATIONS OF THE CALCIUM-ALUMINUM EXCHANGE SYSTEM FOR THE EFFECT OF ACID PRECIPITATION ON SOILS  

EPA Science Inventory

Calcium-aluminum exchange isotherms were generated for three common ion exchange equilibrium equations, and their implications relative to the probable effects of acid rainfall are examined. The equations examined were those of Gaines and Thomas (1953), Vanselow (1932), and Gapon...

124

Activation of the calcium sensing receptor stimulates gastrin and gastric acid secretion in healthy participants  

Microsoft Academic Search

Summary  In 17 adults on a fixed metabolic diet, an 11-day course of cinacalcet increased serum gastrin and basal gastric acid output,\\u000a but not maximal gastric acid output, compared with a placebo. These findings indicate that the calcium sensor receptor plays\\u000a a role in the regulation of gastric acid.\\u000a \\u000a \\u000a \\u000a Introduction  Gastric acid secretion is a complex process regulated by neuronal and hormonal

L. Ceglia; S. S. Harris; H. M. Rasmussen; B. Dawson-Hughes

2009-01-01

125

Synthesis of calcium carbonate polymorphs in the presence of polyacrylic acid  

Microsoft Academic Search

Calcium carbonate precipitates are prepared from a solution of CaCl2 and K2CO3 in the presence of polyacrilic acid. The effect of polyacrilic acid incorporation in the [25–80°C] temperature range on crystal morphologies and CaCO3 precipitated polymorph concentrations are investigated using scanning electron microscopy and X-ray diffraction quantitative microstructural and phase analysis. Large changes in morphology and phase proportions are observed

S. Ouhenia; D. Chateigner; M. A. Belkhir; E. Guilmeau; C. Krauss

2008-01-01

126

Regulation of the arachidonic acid-stimulated respiratory burst in neutrophils by intracellular and extracellular calcium  

Microsoft Academic Search

The respiratory burst is an important physiological function of the neutrophils in killing the bacteria invading in human\\u000a body. We used chemiluminescence method to measure the exogenous arachidonic acid-stimulated respiratory burst, and measured\\u000a the cytosolic free calcium concentration in neutrophils by the fluorescence method. It was found that, on one hand, the arachidonic\\u000a acid-stimulated respiratory burst was enhanced by elevating

Shaokun Chuai; Tianhui Hu; Jiang Liu; Xun Shen

2001-01-01

127

Bioactivity in silica/poly(?-glutamic acid) sol-gel hybrids through calcium chelation.  

PubMed

Bioactive glasses and inorganic/organic hybrids have great potential as biomedical implant materials. Sol-gel hybrids with interpenetrating networks of silica and biodegradable polymers can combine the bioactive properties of a glass with the toughness of a polymer. However, traditional calcium sources such as calcium nitrate and calcium chloride are unsuitable for hybrids. In this study calcium was incorporated by chelation to the polymer component. The calcium salt form of poly(?-glutamic acid) (?CaPGA) was synthesized for use as both a calcium source and as the biodegradable toughening component of the hybrids. Hybrids of 40wt.% ?CaPGA were successfully formed and had fine scale integration of Ca and Si ions, according to secondary ion mass spectrometry imaging, indicating a homogeneous distribution of organic and inorganic components. (29)Si magic angle spinning nuclear magnetic resonance data demonstrated that the network connectivity was unaltered with changing polymer molecular weight, as there was no perturbation to the overall Si speciation and silica network formation. Upon immersion in simulated body fluid a hydroxycarbonate apatite surface layer formed on the hybrids within 1week. The polymer molecular weight (Mw 30-120kDa) affected the mechanical properties of the resulting hybrids, but all hybrids had large strains to failure, >26%, and compressive strengths, in excess of 300MPa. The large strain to failure values showed that ?CaPGA hybrids exhibited non-brittle behaviour whilst also incorporating calcium. Thus calcium incorporation by chelation to the polymer component is justified as a novel approach in hybrids for biomedical materials. PMID:23632373

Valliant, Esther M; Romer, Frederik; Wang, Daming; McPhail, David S; Smith, Mark E; Hanna, John V; Jones, Julian R

2013-04-28

128

Yeast adaptation to weak acids prevents futile energy expenditure.  

PubMed

Weak organic acids (WOAs) are widely used preservatives to prevent fungal spoilage of foods and beverages. Exposure of baker's yeast Saccharomyces cerevisiae to WOA leads to cellular acidification and anion accumulation. Pre-adaptation of cultures reduced the rate of acidification caused by weak acid exposure, most likely as a result of changes in plasma membrane or cell wall composition. In order to adapt to sublethal concentrations of the acids and grow, yeast cells activate ATP consuming membrane transporters to remove protons and anions. We explored to what extent ATP depletion contributes to growth inhibition in sorbic or acetic acid treated cells. Therefore, we analyzed the effect of the reduction of proton and anion pumping activity on intracellular pH (pHi), growth, and energy status upon exposure to the hydrophilic acetic acid (HA) and the lipophilic sorbic acid (HS). ATP concentrations were dependent on the severity of the stress. Unexpectedly, we observed a stronger reduction of ATP with growth reducing than with growth inhibitory concentrations of both acids. We deduce that the not the ATP reduction caused by proton pumping, but rather the cost of sorbate anion pumping contributes to growth inhibition. A reduction of proton pumping activity may reduce ATP consumption, but the resulting decrease of pHi affects growth more. ATP utilization was differentially regulated during moderate and severe stress conditions. We propose that the energy depletion alone is not the cause of growth inhibition during HA or HS stress. Rather, the cells appear to reduce ATP consumption in high stress conditions, likely to prevent futile cycling and maintain energy reserves for growth resumption in more favorable conditions. The mechanism for such decision making remains to be established. PMID:23781215

Ullah, Azmat; Chandrasekaran, Gayathri; Brul, Stanley; Smits, Gertien J

2013-06-11

129

Habit modification of calcium carbonate in the presence of malic acid  

NASA Astrophysics Data System (ADS)

The ability of malic acid to control calcium carbonate morphology has been investigated by aging calcium chloride solution in the presence of urea in a 90 °C bath. Malic acid favors the formation of calcite. A transition from single block to aggregate with special morphology occurs upon increasing malic acid concentration. The morphological development of CaCO3 crystal obviously depends on the starting pH. CaCO3 crystal grows from spindle seed to dumbbell in the pH regime from 7 to 11; while it evolves from spindle seed, through peanut, to sphere at pH=11.5. Both dumbbell and sphere consist of rods that are elongated along c-axis and capped with three smooth, well-defined rhombic {1 0 4} faces. A tentative growth mechanism is proposed based on the fractal model suggested by R. Kniep and S. Busch [Angew. Chem. Int. Ed. Engl. 35 (1996) 2624].

Mao, Zhaofeng; Huang, Jianhua

2007-02-01

130

Ascorbic acid in idiopathic recurrent calcium urolithiasis in humans – does it have an abettor role in oxalate, and calcium oxalate crystallization?  

Microsoft Academic Search

The role of ascorbic acid (ASC) in the pathophysiology of renal calcium stones is not clear. We evaluated ASC in blood and\\u000a urine of fasting male patients with idiopathic calcium urolithiasis (ICU) and healthy volunteers. Using smaller subgroups,\\u000a we also evaluated their response to exogenous ASC [either intravenous or oral ASC (5?mg\\/kg bodyweight)] administered together\\u000a with an oxalate-free test meal.

P. O. Schwille; A. Schmiedl; U. Herrmann; M. Manoharan; J. Fan; V. Sharma; D. Gottlieb

2000-01-01

131

Characterization of modified calcium-silicate cements exposed to acidic environment  

SciTech Connect

Portland cement which is used as a binder in concrete in the construction industry has been developed into a biomaterial. It is marketed as mineral trioxide aggregate and is used in dentistry. This material has been reported to be very biocompatible and thus its use has diversified. The extended use of this material has led to developments of newer versions with improved physical properties. The aim of this study was to evaluate the effect of acidic environments found in the oral cavity on fast setting calcium silicate cements with improved physical properties using a combination of techniques. Two fast setting calcium silicate cements (CSA and CFA) and two cement composites (CSAG and CFAG) were assessed by subjecting the materials to lactic acid/sodium lactate buffer gel for a period of 28 days. At weekly intervals the materials were viewed under the tandem scanning confocal microscope (TSM), and scanning electron microscope (SEM). The two prototype cements exhibited changes in their internal chemistry with no changes in surface characteristics. Since the changes observed were mostly sub-surface evaluation of surface characteristics of cement may not be sufficient in the determination of chemical changes occurring. - Research Highlights: {yields} An acidic environment affects modified fast setting calcium silicate-based cements. {yields} No surface changes are observed in acidic environment. {yields} An acidic environment causes sub-surface changes in the material chemistry which are only visible in fractured specimens. {yields} A combination of techniques is necessary in order to evaluate the chemical changes occurring.

Camilleri, Josette, E-mail: josette.camilleri@um.edu.mt

2011-01-15

132

Effects of acid deposition on calcium nutrition and health of Southern Appalachian spruce fir forests  

SciTech Connect

The role of acid deposition in the health of spruce fir forests in the Southern Appalachian Mountains has been investigated by a wide variety of experimental approaches during the past 10 years. These studies have proceeded from initial dendroecological documentation of altered growth patterns of mature trees to increasingly more focused ecophysiological research on the causes and characteristics of changes in system function associated with increased acidic deposition. Field studies across gradients in deposition and soil chemistry have been located on four mountains spanning 85 km of latitude within the Southern Appalachians. The conclusion that calcium nutrition is an important component regulating health of red spruce in the Southern Appalachians and that acid deposition significantly reduces calcium availability in several ways has emerged as a consistent result from multiple lines or research. These have included analysis of trends in wood chemistry, soil solution chemistry, foliar nutrition, gas exchange physiology, root histochemistry, and controlled laboratory and field studies in which acid deposition and/or calcium nutrition has been manipulated and growth and nutritional status of saplings or mature red spruce trees measured. This earlier research has led us to investigate the broader implications and consequences of calcium deficiency for changing resistance of spruce-fir forests to natural stresses. Current research is exploring possible relationships between altered calcium nutrition and shifts in response of Fraser fir to insect attack by the balsam wooly adelgid. In addition, changes in wood ultrastructural properties in relation to altered wood chemistry is being examined to evaluate its possible role in canopy deterioration, under wind and ice stresses typical of high elevation forests.

McLaughlin, S.B.; Wullschleger, S. [Oak Ridge National Lab., TN (United States); Stone, A. [Univ. of Tennessee, Knoxville, TN (United States); Wimmer, R. [Austrian Agricultural Univ., Vienna (Austria); Joslin, J.D.

1995-02-01

133

Surface modification of calcium hydroxyapatite by grafting of etidronic acid  

NASA Astrophysics Data System (ADS)

Our studies of apatite-etidronic acid hybrid compounds highlight the influence of apatitic surface in grafting process.We showed that the apatitic surface possesses two different functional groups CaOH and POH acting as the active sites.Synthesizing CaHAp-(ETD) composites offers a relevant tool as possible application as biomaterials to repair bone tissues.

Othmani, Masseoud; Aissa, Abdallah; Bac, Christophe Goze; Rachdi, Férid; Debbabi, Mongi

2013-06-01

134

Steel corrosion protection by means of alkyd paints pigmented with calcium acid phosphate  

SciTech Connect

The use of classic anticorrosive pigments is becoming more and more restricted by increasing environmental concerns; they are gradually being replaced by zinc phosphate and related compounds. Other anticorrosive pigments such as surface-exchanged silicas were also proposed. The object of this research is to study the anticorrosive properties of calcium acid phosphate as an inhibitive pigment, introducing a careful selection of complementary pigments in order to achieve an efficient anticorrosive protection. Several alkyd paints were prepared and evaluated through accelerated and electrochemical tests. The nature of the passive film formed was also studied. Paint containing zinc oxide and calcium carbonate (50/50) as complementary pigments showed the best performance in the salt spray test. Zinc oxide and calcium carbonate decreased film permeability and improved steel passivation. The passive film was composed of ferric oxyhydroxide, the pores of which became plugged by ferric phosphate.

Amo, B. del; Romagnoli, R.; Vetere, V.F. [CIC-CONICET, La Plata (Argentina)

1999-06-01

135

Filler modification for papermaking with starch/oleic acid complexes with the aid of calcium ions.  

PubMed

To mitigate the negative effect of filler addition on paper strength and improve filler retention, filler modification with hydrogen bonding polymers (e.g., starch) or their composites is an interesting research topic. Differing from previous reports, the concept related to the deposition of starch/oleic acid complexes on precipitated calcium carbonate (PCC) with the aid of calcium ions was demonstrated. The introduction of calcium ions resulted in effective starch deposition. As a result of filler modification, filler retention and the tensile strength of the filled paper were simultaneously improved essentially due to the aggregation of PCC particles in filler modification process as well as improved filler bondability. The concept demonstrated in this brief study may provide an alternative approach to filler bondability enhancement for improved papermaking performances. PMID:23987430

Huang, Xiujie; Shen, Jing; Qian, Xueren

2013-07-12

136

Nimodipine, a dihydropyridine-type calcium channel blocker, prevents alcoholic hepatitis caused by chronic intragastric ethanol exposure in the rat  

Microsoft Academic Search

It has been shown recently that inactivation of Kupffer cells prevents free radical formation and early alcohol-induced liver injury, and that hypoxia subsequent to a hypermetabolic state caused by activated Kupffer cells is likely involved in the mechanism. Calcium is essential for the activation of Kupffer cells, which contain L-type voltage-dependent Ca2+ channels. Therefore, the purpose of this study was

Y Iimuro; K Ikejima; ML Rose; BU Bradford; RG Thurman

1996-01-01

137

Cytoplasmic calcium level and membrane fluidity of platelets contacting poly(acrylamide-co-methacrylic acid) particles with different surface properties  

Microsoft Academic Search

Changes in cytoplasmic free calcium levels and membrane fluidity of platelets in contact with poly(acrylamide-co-methacrylic acid) (PAAmMAc) particles were examined to analyze the mechanistic aspect of regulating platelet function. Our previous studies demonstrated interesting features of PAAmMAc particles during interaction with platelets: (1) PAAmMAc particles induce no calcium increase but enhance membrane fluidity of platelets; (2) thrombin induces no calcium

Nobuhiko Yui; Ken Suzuki; Teruo Okano; Yasuhisa Sakurai; Mitsuru Nakano; Chikako Ishikawa; Keiji Fujimoto; Haruma Kawaguchi

1996-01-01

138

Calcium Antagonists Inhibit Sustained Gibberellic Acid-Induced Growth of Avena (Oat) Stem Segments.  

PubMed Central

The elongation response of Avena sativa (oat) stem segments to gibberellic acid (GA3) is of large magnitude, with high hormonal sensitivity and specificity, but without cell division activity. This system is therefore an excellent model for mechanistic studies on higher plant cell elongation and the action of gibberellin. At millimolar concentrations, the calcium antagonists verapamil, D-600, nicardipine, diltiazem, bepridil, 8-(N,N,-diethylamino)-octyl-3,4,5-trimethoxybenzoate HCl, and lanthanum substantially inhibited the growth of GA3-treated segments but had no effect on the elongation of nonhormone-treated segments. Although verapamil reduced the maximum growth rate and caused premature cessation of growth, even preincubation of the segments with the drug prior to treatment with GA3 failed to inhibit the earliest measured stimulation of growth by the hormone. Inhibition by verapamil was not reversed by increased concentrations of GA3 or calcium. Neither the calcium ionophore A23187 nor agonist BAY K 8644 had any effect on growth. Light microscopic examination of epidermal peels from antagonist-treated internodal tissue revealed no obvious differences from the control except that the cells were not as elongated. Although these results may support a role for calcium ion movement in maintaining the GA3-induced growth of Avena stem segments, they do not support the involvement of calcium ion movement in the hormone-mediated initiation of growth.

Montague, M. J.

1993-01-01

139

Effect of calcium nitrite-based corrosion inhibitor in preventing corrosion of embedded steel in concrete  

Microsoft Academic Search

Due to the corrosion inhibition effect and compatibility with concrete properties, calcium nitrite solution has been widely used, in North America and Asia,. However, investigation has often been restricted to tests using a macrocell corrosion monitoring or measuring corrosion rate in an aqueous condition. This study concerns the assessment of the inhibition effect of calcium nitrite-based corrosion inhibitor using a

K. Y. Ann; H. S. Jung; H. S. Kim; S. S. Kim; H. Y. Moon

2006-01-01

140

Arachidonic and eicosapentaenoic acid metabolism in bovine neutrophils and platelets: effect of calcium ionophore  

SciTech Connect

Substitution of dietary fatty acids has potential for altering the inflammatory response. The purpose of the present study was to define the metabolites of arachidonic acid (AA) and eicosapentaenoic acid (EPA) secreted by bovine peripheral blood neutrophils and platelets. High performance liquid chromatography was used to characterize cyclooxygenase and lipoxygenase metabolites secreted in response to the calcium ionophore A23187. Cells were prelabelled with /sup 3/H-AA or /sup 3/H-EPA prior to challenge with the calcium ionophore. Bovine neutrophils secreted leukotriene B4 (LTB4) and 5-hydroxyeicosatetraenoic acid (5-HETE) as the major metabolites of AA, as well as the corresponding leukotriene B5 (LTB5) and 5-hydroxyeicosapentaenoic acid (5-HEPE) metabolites of EPA. Peptidoleukotrienes derived from /sup 3/H-AA or /sup 3/H-EPA were not detected under these conditions. The major tritiated metabolites secreted from bovine platelets were: thromboxane A2, measured as the stable metabolite thromboxane B2 (TXB2); hydroxyheptadecatrienoic acid (HHT) and 12-HETE derived from /sup 3/H-AA; and the omega-3 analogs TXB3 and 12-HEPE, derived from /sup 3/H-EPA. Preferred substrate specificities existed amongst the AA- and EPA-derived metabolites for the intermediary enzymes involved in the arachidonic acid cascade. These findings support the hypothesis that substitution of membrane-bound AA by EPA has potential for modulation of the host inflammatory response following cellular phospholipid mobilization.

Taylor, S.M.; Laegreid, W.W.; Heidel, J.R.; Straub, K.M.; Liggitt, H.D.; Silflow, R.M.; Breeze, R.G.; Leid, R.W.

1987-09-01

141

Carbonate-containing apatite (CAP) synthesis under moderate conditions starting from calcium carbonate and orthophosphoric acid.  

PubMed

The synthesis of carbonate-containing apatite (CAP) from calcium carbonate and orthophosphoric acid under moderate conditions was investigated. In all cases, complete precipitation of orthophosphate species was observed. The reaction temperature influenced strongly the decomposition of calcium carbonate and therefore the composition of formed products. The reaction temperature of 80 °C was found to be effective for the complete decomposition of calcium carbonate particles after 48 h of reaction. Infra-red spectroscopy (IR), nuclear magnetic resonance (NMR), thermogravimetry/mass spectroscopy (TG-MS) coupling, and X-ray diffraction (XRD) characterizations allowed the identification of the composition of formed products. By increasing the reaction temperature from 20 °C to 80 °C, the content of A-type CAP increased and that of B-type CAP decreased, according to the favorable effect of temperature on the formation of A-type CAP. The total amount of carbonate content incorporated in CAP's structure, which was determined by TG-MS analysis, increased with the reaction temperature and reached up to 4.1% at 80 °C. At this temperature, the solid product was mainly composed of apatitic components and showed the typical flat-needle-like structure of CAP particles obtained in hydrothermal conditions. These results show an interesting one-step synthesis of CAP from calcium carbonate and orthophosphoric acid as low cost but high purity starting materials. PMID:23623121

Pham Minh, Doan; Tran, Ngoc Dung; Nzihou, Ange; Sharrock, Patrick

2013-03-23

142

Resting intracellular calcium concentration, depolarizing Gamma-Aminobutyric Acid and possible role of local estradiol synthesis in the developing male and female hippocampus  

Microsoft Academic Search

The maturation of the hippocampus is impacted by a multitude of factors, including the regulation of intracellular calcium levels. Depolarizing actions of Gamma-Aminobutyric Acid (GABA) can profoundly alter intracellular calcium in immature hippocampal neurons via influx through voltage-gated calcium channels. We here report fundamental sex differences in properties of depolarizing GABA responses and in resting intracellular calcium in neonatal cultured

J. L. Nuñez; M. M. McCarthy

2009-01-01

143

Azelnidipine prevents cardiac dysfunction in streptozotocin-diabetic rats by reducing intracellular calcium accumulation, oxidative stress and apoptosis  

PubMed Central

Background Numerous evidences suggest that diabetic heart is characterized by compromised ventricular contraction and prolonged relaxation attributable to multiple causative factors including calcium accumulation, oxidative stress and apoptosis. Therapeutic interventions to prevent calcium accumulation and oxidative stress could be therefore helpful in improving the cardiac function under diabetic condition. Methods This study was designed to examine the effect of long-acting calcium channel blocker (CCB), Azelnidipine (AZL) on contractile dysfunction, intracellular calcium (Ca2+) cycling proteins, stress-activated signaling molecules and apoptosis on cardiomyocytes in diabetes. Adult male Wistar rats were made diabetic by a single intraperitoneal (IP) injection of streptozotocin (STZ). Contractile functions were traced from live diabetic rats to isolated individual cardiomyocytes including peak shortening (PS), time-to-PS (TPS), time-to-relengthening (TR90), maximal velocity of shortening/relengthening (± dL/dt) and intracellular Ca2+ fluorescence. Results Diabetic heart showed significantly depressed PS, ± dL/dt, prolonged TPS, TR90 and intracellular Ca2+ clearing and showed an elevated resting intracellular Ca2+. AZL itself exhibited little effect on myocyte mechanics but it significantly alleviated STZ-induced myocyte contractile dysfunction. Diabetes increased the levels of superoxide, enhanced expression of the cardiac damage markers like troponin I, p67phox NADPH oxidase subunit, restored the levels of the mitochondrial superoxide dismutase (Mn-SOD), calcium regulatory proteins RyR2 and SERCA2a, and suppressed the levels of the anti-apoptotic Bcl-2 protein. All of these STZ-induced alterations were reconciled by AZL treatment. Conclusion Collectively, the data suggest beneficial effect of AZL in diabetic cardiomyopathy via altering intracellular Ca2+ handling proteins and preventing apoptosis by its antioxidant property.

2011-01-01

144

Flavonoids derived from herbal Epimedium Brevicornum Maxim prevent OVX-induced osteoporosis in rats independent of its enhancement in intestinal calcium absorption  

Microsoft Academic Search

AimFactorial design was used to test our hypothesis whether a group of flavonoids (FE) derived from herbal Epimedium Brevicornum Maxim exerted its preventive effects on estrogen-deficiency-induced osteoporosis mainly through an enhancement in intestinal calcium absorption.

G. Zhang; L. Qin; W. Y. Hung; Y. Y. Shi; P. C. Leung; H. Y. Yeung; K. S. Leung

2006-01-01

145

Recrystallization of calcium sulfate in phosphoric acid solutions; batchwise operation  

NASA Astrophysics Data System (ADS)

id="ab1">A model is presented for the solvent mediated batchwise recrystallization of hemihydrate into dehydrate. The model takes into account the rates of dissolution of hemihydrate and of growth of gypsum. These rates result from the driving forces (under- and supersaturation) that are influenced by temperature and acid concentrations, and from the rate constants, which are mainly affected by impurities. Secondary nucleation can be neglected with respect to the observed recrystallization rates. The presented model can also be applied more generally.

Witkamp, G. J.; Seckler, M. M.; Bruinsma, O. S. L.; van Rosmalen, G. M.

1990-01-01

146

[Calcium antagonists: current and future applications based on new evidence. The mechanisms on lowering serum uric acid level by calcium channel blockers].  

PubMed

In hypertensive subjects, their serum uric acid levels tend to be higher because of decreasing urinary secretion or overproduction of uric acid. Among calcium channel blockers (CCBs) , long acting nifedipine and cilnidipine reveal serum uric acid lowering action. They decrease the production of uric acid precursor in skeletal muscles under anaerobic condition induced by hypertension or insulin resistance. Hyperuricemia is considered to be a risk factor of not only gout but also renal and cardiovascular diseases, thus, it is important to use CCBs without adverse effect on uric acid metabolisms. PMID:20048433

Mizuta, Einosuke; Hamada, Toshihiro; Igawa, Osamu; Shigemasa, Chiaki; Hisatome, Ichiro

2010-01-01

147

Effects of calcium soaps of fatty acids on postpartum reproductive function in beef  

Microsoft Academic Search

ABSTRACT Twelve multiparous Simmental cows (584 kg) were used to determine the influence of calcium soaps of fatty acids (CSFA) incorporated in a range supplement on postpartum reproductive characteristics. Cows were assigned randomly,to receive a control [C; containin grain sorghum,(GS) and soybean meal (SBM)] or CSFA-based (containing were individually , fed CSFA although plasma triglyceride concentrations were similar between treatments.

R. B. Hightshoe; R. C. Cochran; L. R. Corah; G. H. Kiracofe; D. L. Harmon; R. C. Perry

148

Recovery of americium from nitric acid solutions containing calcium by different co-precipitation methods  

Microsoft Academic Search

Recovery of americium from nitric acid solutions was studied by co-precipitation as hydroxide with various ions like calcium, ferric, nickel using sodium hydroxide and ammonium hydroxide. Studies were also carried out to recover americium using lanthanum fluoride and bismuth phosphate co-precipitation. All the methods are able to co-precipitate Am quantitatively. However, co-precipitation of Am with optimum concentration iron using ammonia

M. M. Charyulu; K. Venugopal Chetty; D. G. Phal; Veena Sagar; Sagar D. M. Sagar; S. M. Pawar; R. Swarup; V. V. Ramakrishna; V. Venugopal

2002-01-01

149

Effects of alginic acid from marine algae on calcium carbonate electrodeposited coating  

Microsoft Academic Search

The effect of alginic acid, extracted from the Lessonia trabeculata calcareous marine algae, was studied in the electrocrystallization of calcium carbonate (CaCO3) on indium tin oxide (ITO) transparent electrodes. Scanning electron microscopy, X-ray diffraction-collected data and microscopic observations show that the presence of Mg2+ at the electrolyte induces the magnesium calcite and aragonite phase formation along with the changes in

Jorge Pavez; Juan F. Silva; Francisco Melo

2005-01-01

150

Morphological modifications of electrodeposited calcium phosphate coatings under amino acids effect  

NASA Astrophysics Data System (ADS)

Calcium phosphate coatings are synthesized on titanium alloy (Ti6Al4V) substrates by pulsed electrodeposition. This work aims to observe the morphological modifications of the coating when an amino acid is added to the electrolytic solution used in the process. The effects of two amino acids (glutamic acid and aspartic acid) are studied at a low and a high concentration. The coating morphology is observed at a nanometer scale by field emission gun-scanning electron microscopy (FEG-SEM). The structural characterization of the coating is performed by Fourier transformed infrared spectroscopy (FT-IR), Raman spectroscopy and X-ray diffraction (XRD). Moreover, corrosion measurements of the prosthetic surfaces are carried out by potentiodynamic polarization experiments in a physiological solution named Dulbecco's modified eagle medium (DMEM). The results show that the addition of an amino acid to the electrolytic solution leads to the decrease of the size of the crystallites which compose the prosthetic calcium phosphate coating that becomes denser and less porous than the coatings obtained without amino acid. Consequently, the corrosion behavior of the prosthetic material immersed in DMEM is improved.

Drevet, R.; Lemelle, A.; Untereiner, V.; Manfait, M.; Sockalingum, G. D.; Benhayoune, H.

2013-03-01

151

Folic acid and primary prevention of birth defects.  

PubMed

Birth defects (BDs) are an important public health problem, due to their overall incidence, occurring in 2-3% of live births in European Union. Neural tube defects (NTDs) are among major NTDs, due to their severity and relatively high incidence; in the meanwhile NTDs are also the most effectively preventable BDs to date. In particular, an adequate folic acid (FA) intake reduces both the occurrence and the recurrence of NTDs; FA is the synthetic form of folates, naturally occurring vitamins in a number of foods, especially vegetables. The daily intake of 0.4 mg of FA should be recommended to all women of childbearing age who plan to become pregnant. The Italian Network for Primary Prevention of BDs through FA Promotion has achieved a significant improvement in FA awareness and use in the periconceptional period. Nevertheless, primary prevention of BDs needs to make further progress; the Italian National Centre for Rare Diseases participates in european sureveillance of congenital anomalies (EUROCAT) Joint Action as coordinator of activities on the effectiveness of BDs prevention. Mandatory food fortification with FA has not been introduced in any European country. The health benefits of FA in reducing the risk of NTDs are undisputed; however mechanistic and animal studies suggest a relationship between high FA intakes and increased cancer promotion, while human studies are still inconsistent and inconclusive. A Working Group organized by the European Food Safety Authority pointed out significant uncertainties about fortification safety and the need for more studies; currently, FA intake from fortified foods and supplements should not exceed 1 mg/day in adults. In conclusion, based on up-to-date scientific evidence, the Italian Network strategy pivots on periconceptional supplementation integrated with promotion of healthy eating habits, support to health education, enhancing the role of women in managing life choices about their health and pregnancy and increasing the scientific knowledge about BDs primary prevention. PMID:21915935

Taruscio, Domenica; Carbone, Pietro; Granata, Orietta; Baldi, Francesca; Mantovani, Alberto

152

The activity of ferulic and gallic acids in biofilm prevention and control of pathogenic bacteria  

Microsoft Academic Search

The activity of two phenolic acids, gallic acid (GA) and ferulic acid (FA) at 1000 ?g ml, was evaluated on the prevention and control of biofilms formed by Escherichia coli, Pseudomonas aeruginosa, Staphylococcus aureus and Listeria monocytogenes. In addition, the effect of the two phenolic acids was tested on planktonic cell susceptibility, bacterial motility and adhesion. Biofilm prevention and control

Anabela Borges; Maria J. Saavedra; Manuel Simões

2012-01-01

153

Fabrication and characterization of poly(lactic-co-glycolic acid) microsphere/amorphous calcium phosphate scaffolds.  

PubMed

Although hydroxyapatite (HAP) and ?-tricalcium phosphate have been used extensively as osteoconductive minerals in biomaterial scaffolds for bone regeneration, they lack the capacity to stimulate osteoblastic differentiation of progenitor cells. In contrast, amorphous calcium phosphates (ACPs), which convert to HAP under aqueous conditions, have the potential to facilitate osteoblastic differentiation through the transient local release of calcium and phosphate ions. Therefore, in this study ACPs were synthesized using zinc and zirconia divalent cations as stabilizers (denoted ZnACP and ZrACP, respectively) and compared to HAP. Analysis of ion release into serum-containing cell culture medium revealed transiently elevated levels of calcium and phosphorous, consistent with the enhanced solubility of ZrACP and ZnACP relative to HAP. In addition, X-ray diffraction analysis revealed partial conversion of ZrACP to HAP but no conversion of ZnACP after 96 h. Next, scaffolds were fabricated by sintering mixtures of 300-500 µm poly(D,L-lactic-co-glycolic acid) (PLGA) microspheres and 0.5 wt% calcium phosphate mineral (HAP, ZrACP or ZnACP) at 70 °C for 24 h. Scanning electron microscopy revealed a porous microsphere matrix with calcium phosphate particulates clinging to the microsphere surfaces both prior to and after 14 days in culture medium. Finally, the incorporation of calcium phosphate resulted in a lower compressive modulus in the range 127 to 74-89 MPa. Taken together, these results indicate that ZrACP, ZnACP and HAP minerals exhibit very different properties, and therefore may elicit different osteoblastic responses in vitro. PMID:21312335

Popp, Jenni R; Laflin, Kate E; Love, Brian J; Goldstein, Aaron S

2011-02-10

154

Synergism of ?-linolenic acid, conjugated linoleic acid and calcium in decreasing adipocyte and increasing osteoblast cell growth.  

PubMed

Whole fat milk and dairy products (although providing more energy compared to low- or non-fat products), are good sources of ?-linolenic acid (ALA), conjugated linoleic acid (CLA) and calcium, which may be favorable in modulating bone and adipose tissue metabolism. We examined individual and/or synergistic effects of ALA, CLA and calcium (at levels similar to those in whole milk/dairy products) in regulating bone and adipose cell growth. ST2 stromal, MC3T3-L1 adipocyte-like and MC3T3-E1 osteoblast-like cells were treated with: (a) linoleic acid (LNA):ALA ratios = 1-5:1; (b) individual/combined 80-90 % c9, t11 (9,11) and 5-10 % t10, c12 (10,12) CLA isomers; (c) 0.5-3.0 mM calcium; (d) combinations of (a), (b), (c); and (e) control. Local mediators, including eicosanoids and growth factors, were measured. (a) The optimal effect was found at the 4:1 LNA:ALA ratio where insulin-like growth factor-1 (IGF-1) and IGF binding protein-3 (IGFBP-3) production was the lowest in MC3T3-L1 cells. (b) All CLA isomer blends decreased MC3T3-L1 and increased MC3T3-E1 cell differentiation. (c) 1.5-2.5 mM calcium increased ST2 and MC3T3-E1, and decreased MC3T3-L1 cell proliferation. (d) Combination of 4:1 LNA:ALA + 90:10 % CLA + 2.0 mM calcium lowered MC3T3-L1 and increased MC3T3-E1 cell differentiation. Overall, the optimal LNA:ALA ratio to enhance osteoblastogenesis and inhibit adipogenesis was 4:1. This effect was enhanced by 90:10 % CLA + 2.0 mM calcium, indicating possible synergism of these dietary factors in promoting osteoblast and inhibiting adipocyte differentiation in cell cultures. PMID:23757205

Kim, Youjin; Kelly, Owen J; Ilich, Jasminka Z

2013-06-12

155

Lipoic acid prevents steroid-induced osteonecrosis in rabbits.  

PubMed

The objective of this study was to investigate in vivo effects of lipoic acid (LA) in preventing steroid-induced osteonecrosis and the possible pathway in a rabbit model. Sixty rabbits were divided into 2 groups: rabbits were intraperitoneally injected with LA aqueous solution at 36 mg/kg of body weight per day for 4 weeks in Group A and rabbits were injected with physiologic saline (PS) as a control in Group B. At 2 weeks after starting treatment, they were intramuscularly injected once with 20 mg/kg of methylprednisolone acetate (MPSL). The femora were histopathologically examined for the presence of osteonecrosis. The plasma levels of total cholesterol (TC), low-density lipoprotein (LDL), high-density lipoprotein (HDL), glutathione (GSH), endothelin (ET) and malondialdehyde (MDA) were assayed at 2 weeks after the injection of MPSL. The incidence of osteonecrosis was significantly higher in Group B (73.1%) than in Group A (20.8%). The GSH level was higher in Group A than in Group B after the LA injection. The plasma MDA and ET levels were lower in Group A than in Group B at 2 weeks after the MPSL administration. Lipoic acid can prevent the development of steroid-induced osteonecrosis in rabbits. Inhibited oxidative stress and amendment of vascular endothelial dysfunction is a possible mechanism for this effect. PMID:21431293

Lu, Bang-Bao; Li, Kang-Hua

2011-03-23

156

Dietary intakes and urinary excretion of calcium and acids: a cross-sectional study of women in China?3  

Microsoft Academic Search

The relationship between dietary intakes and urinary calcium was examined in a cross-sectional survey of 764 middle-aged and elderly women with markedly different dietary patterns and lifestyles. Urinary calcium was correlated positively with urinary acids, including titratable acid (r = 0.46, P < 0.0001). ammonia (r = 0.42, P < 0.0001), and sulfate (r = 0.52, P < 0.000 1).

Ji-Fan Ha; Xi-He Zhao; Banoo Parpia

157

Crystallization of calcium sulfate dihydrate under simulated conditions of phosphoric acid production in the presence of aluminum and magnesium ions  

Microsoft Academic Search

The effect of Al3+ and Mg2+ ions, as additives, on the crystallization of gypsum was studied under simulated conditions of the phosphoric acid production. Calcium hydrogen phosphate and sulfuric acid were mixed with dilute phosphoric acid at 80°C, and the turbidity of the reaction mixture was measured at different time periods to calculate the induction time of gypsum crystals formation.

M. M. Rashad; M. H. H. Mahmoud; I. A. Ibrahim; E. A. Abdel-Aal

2004-01-01

158

Bypassing the Rumen in Dairy Ewes: The Reticular Groove Reflex vs. Calcium Soap of Olive Fatty Acids  

Microsoft Academic Search

A3 × 3 Latin Square experiment was designed to compare 2 ways of bypassing the effects of the rumen with olive oil fatty acids in 'Manchega' dairy ewes. Treatments were a control diet, CaOFA (control diet plus 45 g of olive fatty acids as calcium soap), and OO (control plus 45 g\\/d of olive fatty acids as olive oil emulsified

C. Dobarganes García; M. Pérez Hernández; G. Cantalapiedra; J. M. Salas; J. A. Merino

2005-01-01

159

[Calcium and Vitamin D in the treatment and prevention of osteoporosis: the actual dilemma].  

PubMed

Calcium lowers the fracture risk when given together with vitamin D. In many patients the Calcium intake is lower than the recommended amount, because the mean value reported in several studies corresponds just to the recommended intake, which means that half of the population is below. The American Institute of Medicine (IOM) recommends 1200 mg per day. But 1000 mg should be enough in the presence of vitamin D sufficieny, particularly because 800 mg are the lowest limit for avoiding bone loss. In general, higher doses are harmless. When the Calcium intake ca not be increased by nutrition, supplements are indicated. It is not proven that they increase the cardiovascular risk, which anyway was not reported in the combination with vitamin D, neither with nutritional Calcium. Therefore, Calcium hast to be prescribed in the treatment of osteoporosis, after meal. Vitamin D too is deficient in most of the patients with osteoporosis, especially in advanced age, and should be prescribed together with Calcium, because it hardly can be delivered by food. Although there is no toxicity up to 10'000 IU par day, the IOM proposes only 600 IU per day, and by that neglects the fact that this dose hardly leads to a blood level of 25-OH vitamin D which goes along with lower fracture risk, and wich leaves a large part of the patients vitamin D deficient, unfit for optimal reaction to treatment. Swiss, German and American specialists too recommend 800 - 2000 IU per day. PMID:22403108

Burckhardt, Peter

2012-03-01

160

Effects of a reduced calcium, phosphorus and protein intake and of benzoic acid on calcium and phosphorus metabolism of growing pigs  

Microsoft Academic Search

In order to minimise environmental pollution, many pig feeds contain low phosphorus and protein concentrations as well as benzoic acid (BA), an additive which reduces ammonia formation in the slurry. Since both a low P intake and metabolic acidosis compromise bone mineralisation, the effect of a diet with a low concentration of calcium (Ca), phosphorus (P) and crude protein (CP)

A. Gutzwiller; H. D. Hess; A. Adam; D. Guggisberg; A. Liesegang; P. Stoll

2011-01-01

161

On the coating of precipitated calcium carbonate with stearic acid in aqueous medium.  

PubMed

A series of experimental precipitated calcium carbonates (PCCs) coated with commercial stearic acid (stearin), with the coating amount of stearin added to the PCC particles ranging from 3 to 13.5 wt %, were prepared in aqueous medium and characterized by Fourier transform infrared spectroscopy (FTIR), thermogravimetric analysis (TGA), and differential scanning calorimetry (DSC). FTIR and TGA results indicated that only calcium stearate is present without any free stearic acid left on the surface of the produced PCCs. It was also found that the calcium stearate formed on the coated surface is partially chemisorbed and partially physisorbed. Interestingly, the surface coverage of the chemisorbed stearate, determined by the DSC technique in about 3.25 wt %, was much lower than the theoretical full monolayer coverage (4.17 wt %) for the same set of particles. This result was confirmed by determining the amount necessary to cover the filler with a full monolayer of surfactant by means of a dissolution method where the amount of dissolved surface agent, after the coating reaction, was measured by gas chromatography (GC). In other words, a complete chemisorbed monolayer on the surface cannot be reached, even in the presence of an amount of stearate ions far in excess compared to those required by the stoichiometry. This can be explained by considering that the coating in aqueous medium is quite different from solvent or dry coating, since the process is controlled by micelle adsorption, followed by the collapse of micelles into double or multiple layers during the drying stage. PMID:20334413

Shi, Xuetao; Rosa, Roberto; Lazzeri, Andrea

2010-06-01

162

Stabilization of amorphous calcium carbonate by phosphate rich organic matrix proteins and by single phosphoamino acids.  

PubMed

Stable amorphous calcium carbonate (ACC) is a unique material produced naturally exclusively as a biomineral. It was demonstrated that proteins extracted from biogenic stable ACC induce and stabilize synthetic ACC in vitro. Polyphosphate molecules were similarly shown to induce amorphous calcium carbonate formation in vitro. Accordingly, we tested the hypothesis that biogenic ACC induction and stabilization is mediated by the phosphorylated residues of phosphoproteins. We show that extracellular organic matrix extracted from gastroliths of the red claw crayfish Cherax quadricarinatus induce stable ACC formation in vitro. The proteinaceous fraction of this organic matrix is highly phosphorylated and is incorporated into the ACC mineral phase during precipitation. We have identified the major phosphoproteins of the organic matrix and showed that they have high calcium binding capacity. Based on the above, in vitro precipitation experiments with single phosphoamino acids were performed, indicating that phosphoserine or phosphothreonine alone can induce the formation of highly stable ACC. The results indicate that phosphoproteins may play a major role in the control of ACC formation and stabilization and that their phosphoamino acid moieties are key components in this process. PMID:20416381

Bentov, Shmuel; Weil, Simy; Glazer, Lilah; Sagi, Amir; Berman, Amir

2010-04-21

163

In-Situ Cold Temperature XRD of Calcium Phosphate Produced From Organic Phosphoric Acid  

NASA Astrophysics Data System (ADS)

In this study, we synthesized calcium phosphate from an organic phosphoric acid, diethylhexyl phosphoric acid (DEHPA) and calcium hydroxide solution. The reaction involves a sol-gel process with a whitish gel formed. In-situ XRD analysis was then performed on the sample from room temperature to -140° C. At room the XRD diffractogram shows the sample as an amorphous material and as the temperature was further lowered sharp peaks begins to form indicating that the material had becomes crystalline. The peaks were identified to be that calcium hydrogen phosphate (Ca(H2PO4)2) and this indicates that there is no hydroxyl group removal during the cooling process. The relative crystallinity values obtained for the different cooling temperatures show a slow exponential increase on the initial cooling of 0 to -100° C and at further cooling temperatures resulted fast and linear process. Also unlike the in-situ XRD analysis performs at high temperature no phase transformation occurred at this low temperature.

Yusoff, M. S. Meor; Paulus, Wilfred; Muslimin, Masliana

2010-01-01

164

Assessing soil calcium depletion following growth and harvesting of Sitka spruce plantation forestry in the acid sensitive Welsh uplands  

NASA Astrophysics Data System (ADS)

A simple mass balance has been used to estimate soil calcium depletion during the growth of a 50 year old Sitka spruce crop on acid, base-poor peaty podzol soils in upland Wales. Growth of the crop will deplete the soil calcium reserve by an amount (205 kg Ca ha-1) approximately equivalent to the exchangeable calcium pool to the bottom of the profile and equal to 14% of the total soil calcium reserve to the bottom of the B horizon. Despite these predictions, measurements of exchangeable calcium show no differences beneath mature forest and acid grassland, implying that i) weathering rates in forest soils are greater than long-term estimates and predictions by the PROFILE soil chemistry model ii) the trees can access other sources of calcium or iii) there are significant errors in the mass balance. Following stem-only harvesting, growth of a 50 year old second rotation crop will lead to further depletion of soil calcium, but this amount (79 kg Ca ha-1), is less than for a second rotation crop following whole-tree harvesting (197 kg Ca ha-1). After the first crop, stem-only harvesting would allow a further 18 rotations before depletion of the total calcium reserve to the bottom of the B horizon. Whole-tree harvesting would allow for seven rotations after the first crop. These calculations assume that all sources of calcium are equally available to the crop. This can only be resolved by dynamic modelling of the calcium cycle at the ecosystem scale based on appropriate field measurements. The potential for significant soil acidification is therefore greater following whole-tree harvesting and, in line with current recommendations (Nisbet et al., 1997), this technique should probably be avoided on acidic, nutrient-poor soils unless remedial measures are included to enhance the soil base cation status.

Reynolds, B.; Stevens, P. A.

165

Thrombosis Prevention by Acetylsalicylic Acid in Hyperlipemic Rats  

PubMed Central

In rats, administration of acetylsalicylic acid (ASA) by stomach tube two hours before blood removal, or addition of the drug to platelet-rich plasma in vitro, markedly inhibited platelet aggregation induced by thrombin, ADP and collagen. Addition of ASA in vitro to human platelet-rich plasma also inhibited platelet aggregation by thrombin, ADP and collagen. In hyperlipemic rats, ASA (100 to 200 mg./kg.), administered by stomach tube once or five times, markedly inhibited the production of thrombosis initiated by intravenous injection of S. typhosa endotoxin. In these experiments, thrombosis prevention by ASA was associated with both a decrease in platelet aggregation and an increase in the recalcification plasma clotting time.

Renaud, S.; Godu, J.

1970-01-01

166

Preparation of well-defined calcium cross-linked alginate films for the prevention of surgical adhesions.  

PubMed

Abdominal adhesions are one of the major problems associated with abdominal surgeries or abdominal trauma. There are many different therapeutic options to prevent these adhesions, for example, the application of barrier films made of biodegradable polymers like alginate. For many application relevant parameters (mechanical stability, elasticity, erosion, and mucoadhesivity of the films), the extent of cross-linking with divalent cations, such as calcium, is essential to obtain alginate films with clinically ideal properties. All these properties can eventually be strongly influenced by the composition of the films. For this reason, the manufacture of thin films (?20 µm) was improved to accurately control the calcium content and distribution as well as the time and process of cross-linking. The aim of this work was to find the best suited method to evenly distribute the calcium ions in the alginate films and to obtain films with controlled erosion times as well as sufficient flexibility and stability. Furthermore, the influence of plasticizers on the mechanical stability and elasticity was tested to find the amount and type of plasticizers that have to be added to produce the best suited films. PMID:23616398

Esser, Eva; Tessmar, Joerg K V

2013-04-24

167

Effects of alginic acid from marine algae on calcium carbonate electrodeposited coating  

NASA Astrophysics Data System (ADS)

The effect of alginic acid, extracted from the Lessonia trabeculata calcareous marine algae, was studied in the electrocrystallization of calcium carbonate (CaCO3) on indium tin oxide (ITO) transparent electrodes. Scanning electron microscopy, X-ray diffraction-collected data and microscopic observations show that the presence of Mg at the electrolyte induces the magnesium calcite and aragonite phase formation along with the changes in morphology and crystal orientation. Addition of alginic acid strongly inhibits the effect of Mg on the crystallization, receiving in favor of the nucleation and growth of calcite phase of CaCO3. These results suggest that the alginic acid acts as an organic template in the electrocrystallization of CaCO3, controlling the crystallographic orientation of crystal growth, and as a consequence, the crystal morphology.

Pavez, Jorge; Silva, Juan F.; Melo, Francisco

2005-09-01

168

Atherosclerosis and hypertension induction by lead and cadmium ions: an effect prevented by calcium ion  

SciTech Connect

In epidemiological studies, both positive and negative correlations have been found between cardiovascular disease and mortality and the presence of several inorganic ions in the drinking water. In an attempt to resolve this apparent disagreement, we exposed White Carneau pigeons to drinking water containing calcium (100 ppm), magnesium (30 ppm), lead (0.8 ppm), or cadmium (0.6 ppm) and used a 2/sup 4/-factorial design to measure the effects of these elements in atherosclerosis and hypertension. The results indicate that (i) lead and cadmium induced aortic atherosclerosis and hypertension, and (ii) calcium protects against the cardiovascular effects of cadmium. Furthermore, the effects were indications that magnesium antagonized the atherosclerotic protective effect of calcium. We suggest that, if these results with the pigeon can be applied to humans, the incidence of aortic atherosclerosis and hypertension should be significantly higher in areas where the drinking water contains magnesium, lead, and cadmium with a relatively low calcium concentration. Furthermore, if hard and soft water produce similar levels of lead and cadmium uptakes, the level of magnesium may be an additional factor in aortic atherosclerosis.

Revis, N.W. (Oak Ridge National Lab., TN); Zinsmeistery, A.R.; Bull, R.

1981-10-01

169

DELIQUESCENCE BEHAVIOR AND CHEMICAL STABILITY OF VITAMIN C FORMS (ASCORBIC ACID, SODIUM ASCORBATE, AND CALCIUM ASCORBATE) AND BLENDS  

Microsoft Academic Search

The stability and type of vitamin C added to foods is important for enhancing product quality, label claims, and shelf-life. To improve understanding of stability, the effects of deliquescence, storage RH, formulation, and addition of ascorbyl palmitate and dehydroascorbic acid on degradation of vitamin C at 25°C were studied. Individual vitamin C forms (ascorbic acid, sodium and calcium ascorbate) and

Ashley N. Hiatt; Mario G. Ferruzzi; Lynne S. Taylor; Lisa J. Mauer

2010-01-01

170

Deliquescence Behavior and Chemical Stability of Vitamin C Forms (Ascorbic Acid, Sodium Ascorbate, and Calcium Ascorbate) and Blends  

Microsoft Academic Search

The stability and type of vitamin C added to foods is important for enhancing product quality, label claims, and shelf-life. To improve understanding of stability, the effects of deliquescence, storage relative humidity (RH) formulation, and addition of ascorbyl palmitate and dehydroascorbic acid on degradation of vitamin C at 25°C were studied. Individual vitamin C forms (ascorbic acid, sodium, and calcium

Ashley N. Hiatt; Mario G. Ferruzzi; Lynne S. Taylor; Lisa J. Mauer

2011-01-01

171

Application of acidic calcium sulfate and e-polylysine to pre-rigor beef rounds for reduction of pathogens  

Technology Transfer Automated Retrieval System (TEKTRAN)

Foodborne illness continues to be a serious public health problem and is a major concern for the United States food industry. This study evaluated the effectiveness of warm solutions of acidic calcium sulfate (ACS), lactic acid (LA), episolon-polylysine (EPL), ACS plus EPL, and sterile distilled wa...

172

Effect of dietary supplementation with conjugated linoleic acid on markers of calcium and bone metabolism in healthy adult men  

Microsoft Academic Search

Introduction:Conjugated linoleic acid (CLA) has been shown to positively influence calcium and bone metabolism in experimental animals and cells in culture, but there are limited human data available.Objective:To investigate the effect of CLA supplementation on biomarkers of calcium and bone metabolism in healthy adult males.Design:The study consisted of a double-blind, placebo-controlled trial in which 60 healthy adult males (aged 39–64

L Doyle; C Jewell; A Mullen; A P Nugent; H M Roche; K D Cashman

2005-01-01

173

Isolation, Partial Amino Acid Sequence, and Immunohistochemical Localization of a Brain-Specific Calcium-Binding Protein  

Microsoft Academic Search

A calcium-binding protein (protein 10) having a molecular mass of 29 kDa and an isoelectric point of 5.3 was purified from guinea pig brain. The amino acid sequence of fragments from proteolytic digestion of protein 10 revealed an 86% sequence identity with a calcium-binding protein (calretinin) found in chicken retina. Polyclonal antibodies against protein 10 revealed a specific distribution of

Lois Winsky; Hiroyasu Nakata; Brian M. Martin; David M. Jacobowitz

1989-01-01

174

Identification of a specific one amino acid change in recombinant human transglutaminase 2 that regulates its activity and calcium sensitivity.  

PubMed

TG2 (transglutaminase 2) is a calcium-dependent protein cross-linking enzyme which is involved in a variety of cellular processes. The threshold level of calcium needed for endogenous and recombinant TG2 activity has been controversial, the former being more sensitive to calcium than the latter. In the present study we address this question by identifying a single amino acid change from conserved valine to glycine at position 224 in recombinant TG2 compared with the endogenous sequence present in the available genomic databases. Substituting a valine residue for Gly224 in the recombinant TG2 increased its calcium-binding affinity and transamidation activity 10-fold and isopeptidase activity severalfold, explaining the inactivity of widely used recombinant TG2 at physiological calcium concentrations. ITC (isothermal titration calorimetry) measurements showed 7-fold higher calcium-binding affinities for TG2 valine residues which could be activated inside cells. The two forms had comparable substrate- and GTP-binding affinities and also bound fibronectin similarly, but coeliac antibodies had a higher affinity for TG2 valine residues. Structural analysis indicated a higher stability for TG2 valine residues and a decrease in flexibility of the calcium-binding loop resulting in improved metal-binding affinity. The results of the present study suggest that Val224 increases TG2 activity by modulating its calcium-binding affinity enabling transamidation reactions inside cells. PMID:23941696

Kanchan, Kajal; Ergülen, Elvan; Király, Robert; Simon-Vecsei, Zsófia; Fuxreiter, Mónika; Fésüs, László

2013-11-01

175

Dietary magnesium, not calcium, prevents vascular calcification in a mouse model for pseudoxanthoma elasticum  

Microsoft Academic Search

Pseudoxanthoma elasticum (PXE) is a heritable disorder characterized by ectopic calcification of connective tissue in skin,\\u000a Bruch’s membrane of the eye, and walls of blood vessels. PXE is caused by mutations in the ABCC6 gene, but the exact etiology is still unknown. While observations on patients suggest that high calcium intake worsens the\\u000a clinical symptoms, the patient organization PXE International

Theo G. M. F. Gorgels; Jan H. Waarsing; Anneke de Wolf; Jacoline B. ten Brink; Willem J. P. Loves; Arthur A. B. Bergen

2010-01-01

176

High calcium intake does not prevent stress-salt hypertension in dogs  

Microsoft Academic Search

Avoidance conditioning sessions and isotonic saline (1.3 L\\/day) were administered to dogs for 12 days under conditions of\\u000a a low (0.1%) or high (1.5%) calcium diet. Twenty-four-hour mean arterial pressure increased comparably during the stress-salt\\u000a conditioning periods on both the low (systolic: +16 ± 5 mm Hg; diastolic: +6 ± 2 mm Hg) and high (systolic: +17 ± 4 mm

DAVID Eo ANDERSON; Pamela Murphy; William Kearns

1986-01-01

177

Calcium Phosphate Nanoparticles: Toxicology and Lymph Node Targeting for Cancer Metastasis Prevention  

Microsoft Academic Search

\\u000a Applications of nanoparticles in biology are rapidly developing areas in nanomedicine. In cancer therapy, nanoparticles are\\u000a being used for the detection, diagnosis, and imaging of tumors. Calcium phosphate has long been used as a bone substitute\\u000a biomaterial and is FDA approved. It is biocompatible, easy to synthesize and relatively cheap. Due to these favorable conditions,\\u000a it has been investigated for

Rajesh A. Pareta

178

Sigma-1 receptor activation prevents intracellular calcium dysregulation in cortical neurons during in vitro ischemia.  

PubMed

Sigma receptors are putative targets for neuroprotection following ischemia; however, little is known on their mechanism of action. One of the key components in the demise of neurons following ischemic injury is the disruption of intracellular calcium homeostasis. Fluorometric calcium imaging was used to examine the effects of sigma receptor activation on changes in intracellular calcium concentrations ([Ca(2+)](i)) evoked by in vitro ischemia in cultured cortical neurons from embryonic rats. The sigma receptor agonist, 1,3-di-o-tolyl-guanidine (DTG), was shown to depress [Ca(2+)](i) elevations observed in response to ischemia induced by sodium azide and glucose deprivation. Two sigma receptor antagonists, metaphit [1-(1-(3-isothiocyanatophenyl)-cyclohexyl)-piperidine] and BD-1047 (N-[2-3,4-dichlorophenyl)-ethyl]-N-methyl-2-(dimethylamino)ethylamine), were shown to blunt the ability of DTG to inhibit ischemia-evoked increases in [Ca(2+)](i), revealing that the effects are mediated by activation of sigma receptors and not via the actions of DTG on nonspecific targets such as N-methyl-d-aspartate receptors. DTG inhibition of ischemia-induced increases in [Ca(2+)](i) was mimicked by the sigma-1 receptor-selective agonists, carbetapentane, (+)-pentazocine and PRE-084 [2-(4-morpholinethyl) 1-phenylcyclohexanecarboxylate hydrochloride], but not by the sigma-2-selective agonist, ibogaine, showing that activation of sigma-1 receptors is responsible for the effects. In contrast, DTG, carbetapentane, and ibogaine blocked spontaneous, synchronous calcium transients observed in our preparation at concentrations consistent with sigma receptor-mediated effects, indicating that both sigma-1 and sigma-2 receptors regulate events that affect [Ca(2+)](i) in cortical neurons. Our studies show that activation of sigma receptors can ameliorate [Ca(2+)](i) dysregulation associated with ischemia in cortical neurons and, thus, identify one of the mechanisms by which these receptors may exert their neuroprotective properties. PMID:16988055

Katnik, Christopher; Guerrero, Waldo R; Pennypacker, Keith R; Herrera, Yelenis; Cuevas, Javier

2006-09-20

179

Formation of calcium carbonate films on chitosan substrates in the presence of polyacrylic acid  

SciTech Connect

In this investigation, chitosan membranes with different surface average degrees of deacetylation (DA) are prepared and then are employed as the support matrix to culture calcium carbonate (CaCO{sub 3}). In the presence of high concentration of polyacrylic acid (PAA), the CaCO{sub 3} films obtained on the surface of all chitosan films mainly consisted of vaterite, which suggests the presence of bulk PAA plays an overwhelming part in stabilizing the vaterite. As a comparison, the influences of active groups indicate that only in case of low concentration PAA the thin CaCO{sub 3} films grown on chitosan with 8% DA mainly consisted of vaterite owing to the strong nucleation ability of -NH{sub 2} group, whereas, for those grown on chitosan with 80% DA the CaCO{sub 3} films mainly consisted of aragonite. A more complex scenario revealed that in the case of intermediate concentration of PAA the formed polymorphs behave as mixtures of vaterite and aragonite. - Graphical abstract: Chitosan membranes with different degrees of deacetylation (DA) are employed as support to culture calcium carbonate (CaCO{sub 3}). In high concentration of polyacrylic acid (PAA), the CaCO{sub 3} films obtained consisted of vaterite. However, the CaCO{sub 3} film grown on chitosan with 8% DA mainly consisted of vaterite as opposed to aragonite for chitosan with 8% DA. The schematic presentation of the formation of calcium carbonate on chitosan films with different degrees of acetylation in the presence of PAA with low-, mid- and high concentrations.

He, Linghao; Xue, Rui [Zhengzhou University of Light Industry Henan Provincial Key Laboratory of Surface and Interface Science, Henan, Zhengzhou 450002 (China); Song, Rui, E-mail: rsong@gucas.ac.c [Zhengzhou University of Light Industry Henan Provincial Key Laboratory of Surface and Interface Science, Henan, Zhengzhou 450002 (China); College of Chemistry and Chemical Engineering, Graduate University of Chinese Academy of Sciences, Beijing 100049 (China)

2009-05-15

180

Calcium and bone disease  

PubMed Central

Calcium transport and calcium signaling are of basic importance in bone cells. Bone is the major store of calcium and a key regulatory organ for calcium homeostasis. Bone, in major part, responds to calcium-dependent signals from the parathyroids and via vitamin D metabolites, although bone retains direct response to extracellular calcium if parathyroid regulation is lost. Improved understanding of calcium transporters and calcium-regulated cellular processes has resulted from analysis of genetic defects, including several defects with low or high bone mass. Osteoblasts deposit calcium by mechanisms including phosphate and calcium transport with alkalinization to absorb acid created by mineral deposition; cartilage calcium mineralization occurs by passive diffusion and phosphate production. Calcium mobilization by osteoclasts is mediated by acid secretion. Both bone forming and bone resorbing cells use calcium signals as regulators of differentiation and activity. This has been studied in more detail in osteoclasts, where both osteoclast differentiation and motility are regulated by calcium.

Blair, Harry C.; Robinson, Lisa J.; Huang, Christopher L.-H.; Sun, Li; Friedman, Peter A.; Schlesinger, Paul H.; Zaidi, Mone

2013-01-01

181

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

PubMed Central

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.

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

2013-01-01

182

Performance of calcium deficient hydroxyapatite-polyglycolic acid composites: an in vitro study.  

PubMed

The strategic incorporation of bioresorbable polymeric additives to calcium-deficient hydroxyapatite cement may provide short-term structural reinforcement and modify the modulus to closer match bone. The longer-term resorption properties may also be improved, creating pathways for bone in-growth. The aim of this study was to investigate the resorption process of a calcium phosphate cement system containing either in polyglycolic acid tri-methylene carbonate particles or polyglycolic acid fibres. This was achieved by in vitro aging in physiological conditions (phosphate buffered solution at 37 degrees C) over 12 weeks. The unreinforced CPC exhibited an increase in compressive strength at 12 weeks, however catastrophic failure was observed above a critical loading. The fracture behaviour of cement was improved by the incorporation of PGA fibres; the cement retained its cohesive structure after critical loading. Gravimetric analysis and scanning electron microscopy showed a large proportion of the fibres had resorbed after 12 weeks allowing for the increased cement porosity, which could facilitate cell infiltration and faster integration of natural bone. Incorporating the particulate additives in the cement did not provide any mechanism for mechanical property augmentation or did not demonstrate any appreciable level of resorption after 12 weeks. PMID:20204469

Dunne, Nicholas; Jack, Valerie; O'Hara, Rochelle; Farrar, David; Buchanan, Fraser

2010-03-05

183

Lipoic Acid Prevents the Changes of Intracellular Lipid Partitioning by Free Fatty Acid  

PubMed Central

Background/Aims It is suggested that the hepatic lipid composition is more important than lipid quantity in the pathogenesis of non-alcoholic steatohepatitis. We examined whether lipoic acid (LA) could alter intrahepatic lipid composition and free cholesterol distribution. Methods HepG2 cells were cultured with palmitic acid (PA) with and without LA. Apoptosis, changes of the mitochondrial structure, intracellular lipid partitioning, and reactive oxygen species (ROS) activity were measured. Results Free fatty acid (FA) increased apoptosis, and LA co-treatment prevented this lipotoxicity (apoptosis in controls vs PA vs PA+LA, 0.5% vs 19.5% vs 1.6%, p<0.05). LA also restored the intracellular mitochondrial DNA copy number (553±33.8 copies vs 291±14.55 copies vs 421±21.05 copies, p<0.05) and reversed the morphological changes induced by PA. In addition, ROS was increased in response to PA and was decreased in response to LA co-treatment (41,382 relative fluorescence unit [RFU] vs 43,646 RFU vs 41,935 RFU, p<0.05). LA co-treatment increased the monounsaturated and polyunsaturated FA concentrations and decreased the total saturated FA fraction. It also prevented the movement of intracellular free cholesterol from the cell membrane to the cytoplasm. Conclusions LA opposes free FA-generated lipotoxicity by altering the intracellular lipid composition and free cholesterol distribution.

Kim, Dong Chan; Jang, Eun Chul; Kim, Sang Heum; Kim, Eun Kyung; Lee, Sang Pyo; Lee, Kang Nyeong; Lee, Hang Lak; Lee, Oh Young; Yoon, Byung Chul; Choi, Ho Soon

2013-01-01

184

A new fluoride preparation for the prevention of postmenopausal osteoporosis: calcium monofluorophosphate.  

PubMed

Fifty-six postmenopausal women aged 52.4 +/- 6.7 years (SD) were treated for 12 months with L-glutamine calcium monofluorophosphate. Each patient received four tablets/day, providing a total dose of 20 mg of fluoride and 600 mg of elemental calcium. Bone mineral density was measured at baseline and after 6 and 12 months of treatment by dual photon absorptiometry of the distal forearm. At these times, serum levels of alkaline phosphatase and osteocalcin, and urinary concentrations of hydroxyproline and calcium, were also assayed. Results were compared with a control group of 50 untreated postmenopausal women with similar clinical characteristics. Forty-nine patients completed the study. Bone mineral density in the treated patients showed a significant increase after 6 months in comparison with both baseline (p < 0.01) and controls (p < 0.01). After 12 months no significant further increase in bone mineral density was detected. In the control group, a significant decrease of bone mineral density was observed at this time (p < 0.01). After 6 months, serum osteocalcin levels were significantly increased in the treated group (p < 0.01 vs. basal and controls). The other biochemical parameters did not show any significant variations. After 12 months, all the biochemical parameters evaluated, with the exception of serum alkaline phosphatase, were significantly different in comparison with the control group (p < 0.01). Osteocalcin levels also increased in comparison with the basal value (p < 0.01). Adverse effects were mild. However, seven patients stopped the treatment before the 6th month because of gastrointestinal complaints.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:8291458

Affinito, P; Di Carlo, C; Primizia, M; Petrillo, G; Napolitano, V; Tremolaterra, F; Nappi, C

1993-09-01

185

Evaluating the relationship of calcium and vitamin D in the prevention of stress fracture injuries in the young athlete: a review of the literature.  

PubMed

Calcium and vitamin D are recognized as 2 components of nutrition needed to achieve and maintain bone health. Calcium and vitamin D have been clearly shown to improve bone density and prevent fractures at all ages. However, the literature is conflicting as to the role of these nutrients in young athletes ages 18 to 35 years, both for bone development and for the prevention of bone overuse injuries. Differences in findings may relate to study design. Although retrospective and cross-sectional studies have had mixed results, the authors of prospective studies have consistently demonstrated a relationship of increased calcium intake with an improvement in bone density and a decrease in fracture risk. A randomized trial in female military recruits demonstrated that calcium/vitamin D supplementation reduced the incidence of stress fractures. A prospective study in young female runners demonstrated reduced incidence of stress fractures and increased bone mineral density with increased dietary calcium intake. Findings from both studies suggest female athletes and military recruits who consumed greater than 1500 mg of calcium daily exhibited the largest reduction in stress fracture injuries. To date, no prospective studies have been conducted in male athletes or in adolescent athletes. In most studies, males and nonwhite participants were poorly represented. Evidence regarding the relationship of vitamin D intake with the prevention of fractures in athletes is also limited. More prospective studies are needed to evaluate the role of calcium and vitamin D intake in prevention of stress fracture injuries in both male and female adolescent athletes, particularly those participating in sports with greater incidences of stress fracture injury. PMID:20970764

Tenforde, Adam S; Sayres, Lauren C; Sainani, Kristin L; Fredericson, Michael

2010-10-01

186

Assessment the levels of tartrate-resistant acid phosphatase (TRAP) on mice fed with eggshell calcium citrate malate.  

PubMed

Optimized conditions were obtained by one-factor-at-a-time test (OFAT) and ternary quadratic regression orthogonal composite design (TQROCD) respectively. By pulse electric fields (PEF) technology, the process of eggshell calcium citrate malate (ESCCM), eggshell calcium citrate (ESCC) and eggshells calcium malate (ESCM) were comprehensive compared. The levels of tartrate-resistant acid phosphatase (TRAP) and the bioavailability on mice fed with eggshell calcium citrate malate (ESCCM) treated by pulsed electric field (PEF) were evaluated. Results showed that the rates of calcium dissolution of the different acids studied can be arranged as ESCCM (7.90 mg/mL)>ESCC (7.12 mg/mL)>ESCM (7.08 mg/mL) from highest to lowest rate of dissolution. At the same dose 133.0 mg kg(-1) d(-1), the levels of TRAP in the ESCCM treatment groups were significantly lower than those in ESCM and ESCC (P<0.05). Bone calcium content in the mice fed with ESCCM was generally higher than fed with ESCM and ESCC. PMID:23603074

Yu, Yiding; Zhang, Mingdi; Lin, Songyi; Wang, Liyan; Liu, Jingbo; Jones, Gregory; Huang, Hsiang-Chi

2013-04-18

187

Mechanism of Diastolic Stiffening of the Failing Myocardium and Its Prevention by Angiotensin Receptor and Calcium Channel Blockers  

PubMed Central

Objective To investigate the mechanism responsible for the increased cardiac stiffness associated with hypertensive heart failure in Dahl salt-sensitive (DS) rats and the effects of treatment with the combination of a calcium channel blocker [azelnidipine (AZE)] and angiotensin II type 1 receptor blocker [olmesartan (OLM)]. Methods DS rats fed a high-salt diet from 7 weeks of age were treated (or not) from 12 to 19 weeks of age with the vasodilator hydralazine, OLM plus AZE, or the reduced nicotinamide adenine dinucleotide phosphate (NADPH) oxidase inhibitor apocynin. Rats fed a low-salt diet served as controls. Results Treatment with OLM plus AZE attenuated changes in the expression of collagen isoforms and a decrease in the ratio of elastin to collagen in the left ventricle and prevented the increase in myocardial stiffness and diastolic dysfunction in DS rats in a manner independent of the hypotensive effect of these drugs. Such treatment also inhibited the expression and activation of elastolytic proteases (including cathepsins S and K and metalloproteinases-2, -9, and -12), NADPH oxidase–dependent superoxide production, and inflammatory changes in the failing myocardium. All these effects were mimicked by treatment with apocynin. Conclusions The changes in collagen isoform expression and the decrease in the elastin to collagen ratio in the failing myocardium likely account for the increase in diastolic stiffness in this model of hypertensive heart failure. Administration of angiotensin receptor and calcium channel blockers prevented these changes in a manner independent of the hypotensive effect of these drugs by inhibiting the increase in elastolytic activity induced by activation of NADPH oxidase.

Cheng, Xian Wu; Okumura, Kenji; Kuzuya, Masafumi; Jin, Zhehu; Nagata, Kohzo; Obata, Koji; Inoue, Aiko; Hirashiki, Akihiro; Takeshita, Kyosuke; Unno, Kazumasa; Harada, Ken; Shi, Guo-Ping; Yokota, Mitsuhiro; Murohara, Toyoaki

2010-01-01

188

Calcium and humic acid affect seed germination, growth, and nutrient content of tomato (Lycopersicon esculentum L.) seedlings under saline soil conditions  

Microsoft Academic Search

The effects of calcium and humic acid on seed germination, growth and macro- and micro-nutrient contents of tomato (Lycopersicon esculentum L.) seedlings in saline soil conditions were evaluated. Different levels of humic acid (0, 500, 1000 and 2000 mg kg) and calcium (0, 100, 200 and 400 mg kg) were applied to growth media treated with 50 mg NaCl kg

Önder Türkmen; Atilla Dursun; Metin Turan; Çeknas Erdinç

2004-01-01

189

Dehydration of aliphatic alcohols on phosphoric acid catalyst with the addition of calcium phosphate  

SciTech Connect

The kinetic regularities of dehydration of sec- and tert-butyl alcohols on a catalyst consisting of a mixture of calcium phosphate and H/sub 3/PO/sub 4/, deposited on molten quartz were studied by pulsed gas chromatography. At an equal water vapor pressure in the system, the activity of a catalyst consisting of a pure H/sub 3/PO/sub 4/ is higher than that of a catalyst with the addition of a salt. The experimentally observed dehydration rate constants and those determined with the retention volumes taken into account were measured. Activation energies, rate constants, and the heat of dissolution of tert-butyl alcohol on calcium phosphate catalyst were determined in the range of 80-110/sup 0/C. The dehydration of sec-butyl alcohol was studied at 140/sup 0/C. It was found that in a liquid phase, the reaction rate constant is not very dependent on the salt/acid ratio.

Obraztsov, P.A.; Batalin, O.E.; Malinskii, V.S.; Shubenok, L.F.; Vinnik, M.I.

1986-12-01

190

Fabrication of novel calcium phosphate/poly(lactic acid) fiber composites.  

PubMed

Composites using high-modulus polylactic acid (PLA) fibers coated with calcium phosphate (CaP) were prepared using a cyclic precipitation technique. Scanning electron microscopy revealed that small nuclei of CaP formed after the first soaking cycle, while large quantities of CaP particles were observed after the sixth cycle. The amount of CaP deposited on the PLA yarn increased with deposition time in Ca(2+) and PO(4) (3-) solutions and number of cycles, and decreased with stirring rate during washing cycles. It was observed that around 35 wt % of CaP was deposited on the yarn surface after six cycles of cyclic-soaking. Based on the results, a heterogeneous nucleation and growth mechanism was proposed for the CaP deposition on the surface of hydrolyzed polyester. Composites comprising the coated fibers in a poly(caprolactone) matrix exhibited flexural moduli within the range of that of the cortical bone. PMID:17455279

Kothapalli, Chandrasekhar R; Shaw, Montgomery T; Olson, James R; Wei, Mei

2008-01-01

191

Grafting process of ethyltrimethoxysilane and polyphosphoric acid on calcium carbonate surface  

NASA Astrophysics Data System (ADS)

In order to facilitate its incorporation into a polymer matrix (mostly hydrophobic), calcium carbonate (CaCO3), which is strongly hydrophilic, has to be chemically treated to avoid the formation of aggregates and to improve the compatibility with the polymer. The objective of this study is to analyze, by using contact angle measurements and X-ray photoelectron spectroscopy (XPS), the CaCO3 surface after a chemical surface treatment with ethyltrimethoxysilane (ETMO) and polyphosphoric acid (PPA) in an organic solvent, in order to verify if these molecules are able to interact with the CaCO3 surface, and to propose some hypothesis about the surface grafting mechanism. After several solvent washings were performed to remove all species in excess, contact angle results have pointed out the presence of an organic layer after the chemical treatment of CaCO3 with ETMO and PPA. Based on XPS results, we propose a grafting mechanism of silane and phosphoric acid molecules. Ethyltrimethoxysilane induce an hydrolysis process of the CaCO3 surface which leads to a condensation phenomenon. This SiOH network is adsorbed through hydrogen interactions with some hydroxyl groups. In the case of phosphoric acid, the molecules are adsorbed on carbon atoms through POC bonds formation. This original grafting points out the major role of the solvent nature with CaCO3 surface reactivity.

Kiehl, J.; Ben-Azzouz, C.; Dentel, D.; Derivaz, M.; Bischoff, J. L.; Delaite, C.; Bistac, S.

2013-01-01

192

Effect of molecular weight and concentration of poly(acrylic acid) on the formation of a polymeric calcium phosphate cement  

Microsoft Academic Search

Previous investigations have noted that the tetracalcium phosphate (TTCP)\\/dicalcium phosphate anhydrous (DCPA) apatite forming calcium phosphate cement (CPC) possesses many favorable properties from a biomaterials standpoint. Despite these positive properties various shortcomings have limited clinical usage of these materials and fostered investigations into the effect of numerous additives. The present study concerns the effect of poly(acrylic acid) (PAA) addition and

A. O. Majekodunmi; S. Deb; J. W. Nicholson

2003-01-01

193

Method for removal of surface-active impurities and calcium from conjugated bile salt preparations: comparison with silicic acid chromatography  

Microsoft Academic Search

Some commercial preparations of common natural conjugated bile salts contain impurities (e.g., amines, lipids, and calcium) that are likely to affect their physico- chemical properties. A method was developed for purifying commercial preparations of sodium salts of glycine- and taur- ine-conjugated bile acids. The method consists of passage of a dilute aqueous solution of the sodium bile salt through three

J. Donald Ostrow; Pasupati Mukerjee; Huong-Thu Ton-Nu; Claudio D. Schteingart; Alan F. Hofmann; Carolina Ced; Aldo Roda

194

The effects of citric and acetic acids on the formation of calcium-deficient hydroxyapatite at 38 °C  

Microsoft Academic Search

This study is concerned with the formation of calcium-deficient hydroxyapatite at physiological temperature. Isothermal calorimetry, solution chemistry, scanning electron microscopy, BET surface area analyses and FTIR spectroscopy were used to characterize the kinetics of HAp formation and the microstructure of the HAp formed in varying concentrations of citric and acetic acids, and in deionized water. The kinetics of HAp formation

K. S. Tenhuisen; P. W. Brown

1994-01-01

195

Calcium and temperature effects on seedling exudation and root rot infection of common bean on an acid sandy soil  

Microsoft Academic Search

Soil born fungi such as Phytium ultimum, Fusarium ssp., and Rhizoctonia solani (Kühn) severely restrict stand establishment of common bean (Phaseolus vulgaris L.) on acid soils of the Tropics. Calcium application is known to alleviate fungal infection in many legumes but the causes are still unclear. To investigate environmental factors and physiological mechanisms involved, growth chamber experiments were conducted with

A. Buerkert; H. Marschner

1992-01-01

196

Are cyclopentadienylberyllium, magnesium and calcium hydrides carbon or metal acids in the gas phase?  

PubMed

The structure and bonding of cyclopentadienylberyllium (CpBeH), magnesium (CpMgH), and calcium (CpCaH) hydrides as well as those of their deprotonated species have been investigated by means of B3LYP/6-311+G(3df,2p)//B3LYP/6-311+G(d,p) and B3LYP/6-311+G(3df,2p)//QCISD/6-311+G(d,p) density functional theory (DFT) calculations. The three compounds exhibit C(5v) equilibrium conformations in their ground states. For CpBeH the agreement between the calculated geometry and that determined by MW spectroscopy is excellent. CpMgH and CpCaH can be viewed almost as the result of the interaction between a C?H?? anion and a XH(+) (X = Mg, Ca) cation. Conversely, for CpBeH the interaction between the C?H? and the BeH subunits is significantly covalent. These compounds exhibit a significant aromaticity, usually named three-dimension aromaticity, in contrast with the unsubstituted cyclopentadiene compound. The CpBeH derivative behaves as a C acid in the gas phase and is less acidic than cyclopentadiene. More importantly, CpMgH and CpCaH, in spite of the X(+?)H(-?) polarity exhibited by the X-H bond in the neutral systems, are predicted to be metal acids in the gas phase. Also surprisingly, both the Mg and the Ca derivatives are stronger acids than the Be analogue, and only slightly weaker acids than cyclopentadiene. This somewhat unexpected result is the consequence of two concomitant facts: the lower dissociation energy of the X-H (X = Mg, Ca) bonds with respect to the C-H bonds, and the significantly high electron affinity of the C?H?X* (X = Mg, Ca) radicals. PMID:20396823

Hurtado, Marcela; Lamsabhi, Al-Mokhtar; Mó, Otilia; Yáñez, Manuel; Guillemin, Jean-Claude

2010-05-21

197

Final Report On the Safety Assessment of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, and Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and Tea-Lactates, Methyl, Ethyl, Isopropyl, and Butyl Lactates, and Lauryl, Myristyl, and Cetyl Lactates  

Microsoft Academic Search

This report provides a review of the safety of Glycolic Acid, Ammonium, Calcium, Potassium, and Sodium Glycolates, Methyl, Ethyl, Propyl, and Butyl Glycolates, Lactic Acid, Ammonium, Calcium, Potassium, Sodium, and TEA-Lactates, and Lauryl, Myristyl, and Cetyl Lactates. These ingredients belong to a group known as alpha-hydroxy acids (AHAs). Products containing these ingredients may be for consumer use, salon use, or

F. A. Andersen

1998-01-01

198

Safety assessment of (-)-hydroxycitric acid and Super CitriMax, a novel calcium/potassium salt.  

PubMed

(-)-Hydroxycitric acid (HCA) is a principle constituent (10-30%) of the dried fruit rind of Garcinia cambogia, a plant native to Southeastern Asia. The dried rind has been used for centuries throughout Southeast Asia as a food preservative, flavoring agent and carminative. Extensive experimental studies show that HCA inhibits fat synthesis and reduces food intake. The objective of this review is to systematically review the available safety/toxicity literature on HCA to determine its safety in-use. The primary mechanism of action of HCA appears to be related to its ability to act as a competitive inhibitor of the enzyme ATP-citrate lyase, which catalyzes the conversion of citrate and coenzyme A to oxaloacetate and acetyl coenzyme A (acetyl-CoA), primary building blocks of fatty acid and cholesterol synthesis. Super CitriMax, a novel calcium/potassium-HCA extract (HCA-SX), is considerably more soluble and bioavailable than calcium-based HCA ingredients. Acute oral toxicity studies in animals demonstrate that CitriMax (50% HCA as calcium salt) has a low acute oral toxicity. In a subchronic study in rats, the gavage administration of HCA-SX at doses up to 2500 mg/kg/day for a period of 90 days caused a significant decrease in body weight and reduction in feed consumption without any adverse effects. The structure, mechanism of action, long history of use of HCA and other toxicity studies indicate that HCA-SX is unlikely to cause reproductive or developmental effects. HCA-SX was not mutagenic in the presence or absence of metabolic activation in Ames genotoxicity assays in strains TA98 and TA102. HCA-SX-induced increases in number of revertants in other strains (TA100 and TA1535 in the absence of metabolic activation and in strain TA1537 in the presence of metabolic activation) but these were not considered as biologically indicative of a mutagenic effect. In several, placebo-controlled, double-blind trials employing up to 2800 mg/day HCA, no treatment-related adverse effects were reported. There is sufficient qualitative and quantitative scientific evidence, including animal and human data suggesting that intake of HCA at levels up to 2800 mg/day is safe for human consumption. PMID:15234082

Soni, M G; Burdock, G A; Preuss, H G; Stohs, S J; Ohia, S E; Bagchi, D

2004-09-01

199

Acidic extracellular pH increases calcium influx-triggered phospholipase D activity along with acidic sphingomyelinase activation to induce matrix metalloproteinase-9 expression in mouse metastatic melanoma.  

PubMed

Acidic extracellular pH is a common feature of tumor tissues. We have reported that culturing cells at acidic pH (5.4-6.5) induced matrix metalloproteinase-9 expression through phospholipase D, extracellular signal regulated kinase 1/2 and p38 mitogen-activated protein kinases and nuclear factor-kappaB. Here, we show that acidic extracellular pH signaling involves both pathways of phospholipase D triggered by Ca2+ influx and acidic sphingomyelinase in mouse B16 melanoma cells. We found that BAPTA-AM [1,2-bis(2-aminophenoxy)-ethane-N,N,N',N'-tetraacetic acid tetrakis (acetoxymethyl) ester], a chelator of intracellular free calcium, and the voltage dependent Ca2+ channel blockers, mibefradil (for T-type) and nimodipine (for L-type), dose-dependently inhibited acidic extracellular pH-induced matrix metalloproteinase-9 expression. Intracellular free calcium concentration ([Ca2+]i) was transiently elevated by acidic extracellular pH, and this [Ca2+]i elevation was repressed by EGTA and the voltage dependent Ca2+ channel blockers but not by phospholipase C inhibitor, suggesting that acidic extracellular pH increased [Ca2+]i through voltage dependent Ca2+ channel. In contrast, SR33557, an L-type voltage dependent Ca2+ channel blocker and acidic sphingomyelinase inhibitor, attenuated matrix metalloproteinase-9 induction but did not affect calcium influx. We found that acidic sphingomyelinase activity was induced by acidic extracellular pH and that the specific acidic sphingomyelinase inhibitors (perhexiline and desipramine) and siRNA targeting aSMase/smpd1 could inhibit acidic extracellular pH-induced matrix metalloproteinase-9 expression. BAPTA-AM reduced acidic extracellular pH-induced phospholipase D but not acidic sphingomyelinase acitivity. The acidic sphingomyelinase inhibitors did not affect the phosphorylation of extracellular signal regulated kinase 1/2 and p38, but they suppressed nuclear factor-kappaB activity. These data suggest that the calcium influx-triggered phospholipase D and acidic sphingomyelinase pathways of acidic extracellular pH induced matrix metalloproteinase-9 expression, at least in part, through nuclear factor-kappaB activation. PMID:17540003

Kato, Yasumasa; Ozawa, Shigeyuki; Tsukuda, Mamoru; Kubota, Eiro; Miyazaki, Kaoru; St-Pierre, Yves; Hata, Ryu-Ichiro

2007-06-01

200

A zinc calcium phosphorous oxide ceramic and malic acid-Ca(OH)2-vitamin E composite for repairing bone defects  

Microsoft Academic Search

The objective of this investigation was to develop a resorbable zinc calcium phosphorous ceramic oxide (ZCAP) organic acid-vitamin E composite containing an antibiotic for orthopedic and\\/or dental application, including nearly all cases of trauma of hard tissues. A composite consisting of 3.0 g ZCAP, 1.2 g malic acid, 0.6 g Ca(OH)2 , 9.6 mg gentamicin sulfate and 20 pl of

Andrea Longo; Brian Mehling; Peter Barre; Dale Snead; Ann Taylor; Dave Reynolds; P. K. Bajpai

1995-01-01

201

Improving oxidation stability and mechanical properties of natural rubber vulcanizates filled with calcium carbonate modified by gallic acid  

Microsoft Academic Search

A novel technique to modify the surface of calcium carbonate (CaCO3) nanoparticles, used as an antioxidant and reinforcing filler, by gallic acid is disclosed. The new properties of the modified\\u000a CaCO3 could make it more useful and practical for the rubber industry. Thermal gravimetric (TGA), Fourier transform infrared spectroscopy,\\u000a and transmission electron microscopy analyses showed that the gallic acid was

Sirilux Poompradub; Thirapat Luthikaviboon; Srisuwan Linpoo; Rojrit Rojanathanes; Pattarapan Prasassarakich

2011-01-01

202

Effect of poly(aspartic acid) on calcium phosphate removal from stainless steel tubing under turbulent flow conditions  

NASA Astrophysics Data System (ADS)

Calcium phosphate deposition causes cleaning problems in a number of situations including water treatment, dairy processing, and dental applications. This problem is exacerbated by the limited choices of cleaning chemicals that meet environmental regulations. To promote the development of biodegradable, non-toxic alternatives, this research examines the removal of calcium phosphate deposits consisting of brushite (dicalcium phosphate dihydrate; DCPD) and a mixture of hydroxyapatite (HAP) and DCPD from stainless steel in the presence of poly(aspartic acid) and its sodium salt (PASP). The effects of solvent pH, PASP concentration, and flow rate on the calcium phosphate removal rates are measured from stainless steel tubing under turbulent flow conditions using a solid scintillation detection technique. A mechanistic evaluation of the cleaning data in the absence of PASP indicates that DCPD removal is dominated by shear while HAP/DCPD deposit removal is limited by a combination of mass transfer and interfacial processes. Although the removal mechanisms differ, the results conclusively show that PASP promotes calcium phosphate removal under conditions that favor calcium sequestration in both cases. An in-depth study of DCPD removal in the presence of PASP reveals that this additive is most effective under conditions where calcium sequestration and phosphate protonation occur simultaneously.

Littlejohn, Felicia

203

L-Amino acid sensing by the calcium-sensing receptor: a general mechanism for coupling protein and calcium metabolism?  

Microsoft Academic Search

Cellular sensing of L-amino acids is widespread and controls diverse cellular responses regulating, for example, rates of hormone secretion, amino acid uptake, protein synthesis and protein degradation (autophagy). However, the nature of the sensing mechanisms involved has been elusive. One important sensing mechanism is selective for branched chain amino acids, acts via mTOR (mammalian target of rapamycin) and regulates the

AD Conigrave; AH Franks; EM Brown; SJ Quinn

2002-01-01

204

Effect of Dose of Calcium Salts of Conjugated Linoleic Acid (CLA) on Percentage and Fatty Acid Content of Milk Fat in Midlactation Holstein Cows1  

Microsoft Academic Search

Increasing conjugated linoleic acid (CLA) content of milk fat from lactating dairy cattle has become a re- search interest due to the possible health benefits af- forded humans consuming CLA. Dietary supplementa- tion of CLA to lactating dairy cows is one potential method by which CLA content of milk and dairy prod- ucts may be enhanced. Feeding CLA in calcium

J. G. Giesy; M. A. McGuire; B. Shafii; T. W. Hanson

2002-01-01

205

Dissolution of steelmaking slags in acetic acid for precipitated calcium carbonate production  

Microsoft Academic Search

A promising option for long-term storage of CO2 is to fixate carbon dioxide as magnesium- and calcium carbonates. Slags from iron and steel works are potential raw materials for carbonation due to their high contents of calcium silicates. Precipitated calcium carbonate (PCC) is used as filler and coating materials in paper. If slag could be used instead of limestone for

Sebastian Teir; Sanni Eloneva; Carl-Johan Fogelholm; Ron Zevenhoven

2007-01-01

206

Prevention of aflatoxicosis by addition of hydrated sodium calcium aluminosilicate to the diets of growing barrows.  

PubMed

Hydrated sodium calcium aluminosilicate (HSCAS), an anticaking agent for mixed feed, was added to the diets of growing barrows and was evaluated for its potential to ameliorate the clinical signs of aflatoxicosis. The experimental design consisted of 6 treatments of 5 barrows each at concentrations of 0 g of HSCAS and 0 g of aflatoxin (AF)/kg of feed (control), 5 g of HSCAS/kg of feed (0.5%), 20 g of HSCAS/kg of feed (2.0%), 3 mg of AF/kg of feed, 5 g of HSCAS (0.5%) plus 3 mg of AF/kg of feed, or 20 g of HSCAS (2.0%) plus 3 mg of AF/kg of feed. Barrows were maintained in indoor concrete-floored pens, with feed and water available ad libitum for 28 days (from the age of 7 to 11 weeks). Barrows were observed twice daily and were weighed weekly, and blood samples were obtained weekly for hematologic and serum biochemical measurements. At the termination of the study, barrows were euthanatized and necropsied. Body weight gains were diminished significantly (P less than 0.05) by consumption of 3 mg of AF/kg of feed, whereas body weight gain in barrows consuming diets containing HSCAS or HSCAS plus AF did not differ from that in control barrows. Serum enzymatic activities of alkaline phosphatase and gamma-glutamyl transferase and prothrombin time were increased in barrows consuming 3 mg of AF/kg of feed, but not in those consuming HSCAS or HSCAS plus AF.(ABSTRACT TRUNCATED AT 250 WORDS) PMID:2562791

Harvey, R B; Kubena, L F; Phillips, T D; Huff, W E; Corrier, D E

1989-03-01

207

The L-type calcium channel inhibitor diltiazem prevents cardiomyopathy in a mouse model  

PubMed Central

Dominant mutations in sarcomere protein genes cause hypertrophic cardiomyopathy, an inherited human disorder with increased ventricular wall thickness, myocyte hypertrophy, and disarray. To understand the early consequences of mutant sarcomere proteins, we have studied mice (designated ?MHC403/+) bearing an Arg403Gln missense mutation in the ? cardiac myosin heavy chain. We demonstrate that Ca2+ is reduced in the sarcoplasmic reticulum of ?MHC403/+ mice, and levels of the sarcoplasmic reticulum Ca2+-binding protein calsequestrin are diminished in advance of changes in cardiac histology or morphology. Further evidence for dysregulation of sarcoplasmic reticulum Ca2+ in these animals is seen in their decreased expression of the ryanodine receptor Ca2+-release channel and its associated membrane proteins and in an increase in ryanodine receptor phosphorylation. Early administration of the L-type Ca2+ channel inhibitor diltiazem restores normal levels of these sarcoplasmic reticular proteins and prevents the development of pathology in ?MHC403/+ mice. We conclude that disruption of sarcoplasmic reticulum Ca2+ homeostasis is an important early event in the pathogenesis of this disorder and suggest that the use of Ca2+ channel blockers in advance of established clinical disease could prevent hypertrophic cardiomyopathy caused by sarcomere protein gene mutations.

Semsarian, Christopher; Ahmad, Imran; Giewat, Michael; Georgakopoulos, Dimitrios; Schmitt, Joachim P.; McConnell, Bradley K.; Reiken, Steven; Mende, Ulrike; Marks, Andrew R.; Kass, David A.; Seidman, Christine E.; Seidman, J.G.

2002-01-01

208

Hypercalcemia, metabolic alkalosis and renal failure secondary to calcium bicarbonate intake for osteoporosis prevention--'modern' milk alkali syndrome: a case report.  

PubMed

We report a case of a patient presenting with a triad of hypercalcemia, metabolic alkalosis and renal failure secondary to calcium bicarbonate intake for osteoporosis prevention. It is the classical presentation of the "modern" milk alkali syndrome that presents several characteristics distinguishing it from the "old" syndrome described secondary to peptic ulcer disease treatment. Milk alkali syndrome affects middle-aged female patients taking over-the-counter calcium carbonate. Clinically, these patients present in an acute hypercalcemia crisis, responding rapidly to hydration. The phosphorus level is normal to low. Bisphosphonate should be used cautiously due to the risk of symptomatic hypocalcemia. PMID:19918560

Waked, Alain; Geara, Abdallah; El-Imad, Badiaa

2009-08-06

209

The actual role of hyaluronic acid-based and calcium hydroxylapatite soft tissue fillers: a guide for a practicing dermatologist.  

PubMed

Soft tissue fillers (STFs) together with botulinum toxin have profoundly improved our possibilities to rejuvenate the face and other parts of human body. Among many types of STFs currently used for esthetic and medical indications in routine clinical practice dominate hyaluronic acid-based STFs and calcium hydroxylapatite. Collagen fillers (bovine, porcine and human) are gradually leaving the market replaced mostly by hyaluronic acid-based STFs. This review presents an overview of the physicochemical properties, mechanisms of action and techniques used for the correct placement of hyaluronic acid-based STFs and calcium hydroxylapatite and the most common esthetic indications for these fillers. Finally, we present the recent data on their efficacy and most common complications encountered. PMID:22648331

Pavlovi?, M; Adami?, M; Schuller Petrovi?, S

2012-06-01

210

Tetradecylthioacetic acid prevents high fat diet induced adiposity and insulin resistance  

Microsoft Academic Search

Tetradecylthioacetic acid (TTA) is a non- ? -oxi- dizable fatty acid analog, which potently regulates lipid ho- meostasis. Here we evaluate the ability of TTA to prevent diet-induced and genetically determined adiposity and insu- lin resistance. In Wistar rats fed a high fat diet, TTA admin- istration completely prevented diet-induced insulin resis- tance and adiposity. In genetically obese Zucker (fa\\/fa)

Lise Madsen; Michéle Guerre-Millo; Esben N. Flindt; Kjetil Berge; Karl Johan Tronstad; Elin Bergene; Elena Sebokova; Arild C. Rustan; Jørgen Jensen; Susanne Mandrup; Karsten Kristiansen; Iwar Klimes; Bart Staels; Rolf K. Berge

211

MINE WASTE TECHNOLOGY PROGRAM PREVENTION OF ACID MINE DRAINAGE GENERATION FROM OPEN-PIT HIGHWALLS  

EPA Science Inventory

This document summarizes the results of Mine Waste Technology Program Activity III, Project 26, Prevention of Acid Mine Drainage Generation from Open-Pit Highwalls. The intent of this project was to obtain performance data on the ability of four technologies to prevent the gener...

212

[Role of omega-3 fatty acids in cardiovascular disease prevention].  

PubMed

Fatty acids, in addition to its known energy value and its structural function, have other beneficial properties. In particular, the polyunsaturated fatty acids omega-3 acting on the cardiovascular apparatus through many channels exerting a protective effect against cardiovascular risk. The benefits associated with the reduction in cardiac mortality and sudden death particular, are related to the incorporation of EPA and DHA in phospholipid membrane of cardiomyocytes. An index is established that relates the percentage of EPA + DHA of total fatty acids in erythrocytes and risk of death from cardiovascular disease may layering in different degrees. Therefore, the primary source of fatty fish w-3 PUFA, behaves like a reference food in cardiosaludables diets. PMID:23808424

Piñeiro-Corrales, Guadalupe; Lago Rivero, N; Culebras-Fernández, Jesús M

213

Intravenous infusion of lipid for the prevention of essential fatty acid deficiency in premature infants13  

Microsoft Academic Search

This study was designed to determine the amount of linoleic acid required to prevent essential fatty acid deficiency in premature infants. This was achieved by infusing 1 g intravenous lipid . kg ' . d ' over 18-20 h beginning on day 2 and increasing by 0.5 g- kg' #{149}d' to a maximum of 3 g . kg ' .

Gary R Gutcher; Philip M Farrell

214

Cisternal irrigation therapy with urokinase and ascorbic acid for prevention of vasospasm after aneurysmal subarachnoid hemorrhage  

Microsoft Academic Search

BACKGROUNDCisternal irrigation therapy with urokinase and ascorbic acid was introduced to prevent symptomatic vasospasm after aneurysmal subarachnoid hemorrhage (SAH). To dissolve and wash out the subarachnoid clot, cisternal irrigation with urokinase is used. Ascorbic acid is added to degenerate oxy-hemoglobin, one of the strongest spasmogenic substances, into verdohemelike products, which are nonspasmogenic. The efficacy and safety of this therapy were

Namio Kodama; Tatsuya Sasaki; Masahisa Kawakami; Masahiro Sato; Jun Asari

2000-01-01

215

Calcium balance and acid-base status of women as affected by increased protein intake and by sodium bicarbonate ingestion13  

Microsoft Academic Search

Six women, aged 38 to 62 yr. participated in a 40-day metabolic study to investigate the effect of level of protein intake and of sodium bicarbonate ingestion on urinary calcium, net calcium balance, net renal acid excretion, and arterialized venous blood pH and bicarbonate ion concentration. The diet contained 44 g protein during the first 16 days and 102 g

Josephine Lutz

216

Chelation of Extracellular Calcium-Induced Cell Death was Prevented by Glycogen Synthase Kinase3 Inhibitors in PC12 Cells  

Microsoft Academic Search

Calcium ion is a secondary messenger that mediates a variety of physiological responses of neurons, including cell survival\\u000a responses. To determine the role of calcium in regulating neuronal survival and death, we examined whether chelation of extracellular\\u000a calcium with EGTA induces caspase-dependent apoptotic cell death and whether glycogen synthase kinase-3 is involved in EGTA-induced\\u000a cell death in PC12 cells. EGTA

Tsuneo Takadera; Megumi Ohtsuka; Haruka Aoki

2010-01-01

217

Natto mucilage containing poly-gamma-glutamic acid increases soluble calcium in the rat small intestine.  

PubMed

We prepared natto (fermented soybeans) mucilage containing poly-gamma-glutamic acid (gamma-PGA) from commercial natto. The effect of natto mucilage on calcium (Ca) solubility in vitro and in vivo was investigated. Ca solubility in vitro increased with an increase in the amount of natto mucilage, due to inhibition of the formation of an insoluble complex of Ca with phosphate by natto mucilage. Rats were fed with 5 g of soybean protein isolate, natto, mucilage-free natto, or natto mucilage diet for 1.5 h. Small intestinal contents were collected 2.5 h after ingestion. In the lower half of the small intestine, both the amount and the percentage of soluble Ca of intestinal contents were significantly higher (P < 0.001) in rats fed with natto mucilage diet than in those fed with the other diets. Natto mucilage also increased Ca solubility in vivo. These results suggested that gamma-PGA is responsible for the increasing effect of natto mucilage on Ca solubility. PMID:11330662

Tanimoto, H; Mori, M; Motoki, M; Torii, K; Kadowaki, M; Noguchi, T

2001-03-01

218

Omega-3 Fatty Acids Unlikely to Prevent Cancer  

Cancer.gov

An analysis of numerous, large population cohort studies did not detect evidence of a significant link between dietary intake of omega-3 fatty acids (found in fish) and the incidence of several major cancer types, according to a review study published in the January 25, 2006, issue of the Journal of the American Medical Association.

219

The effect of phosphoric acid concentration on the synthesis of nano-whiskers of calcium metaphosphate by chemical precipitation Method  

NASA Astrophysics Data System (ADS)

Calcium metaphosphate (CMP) nano-whiskers were produced by a chemical precipitation method. In order to produce nano-powders, CMP was prepared by the mixing of two precursors, calcium oxide (CaO) and phosphate acid (H3PO4). Sparingly soluble chemicals, the Ca/P ratio of the mixture was set to be 0.50 to produce stoichiometric CMP, were chemical agitated in phosphate acid solution. At least 3 hours of pre-hydrolysis of phosphorus precursor were required to obtain CMP phase. The CMP powders were dried in a drying oven at 60 °C for 7 days and then followed by a heat treatment at 390 °C for 8hours. The obtained powder was analyzed using XRD, XRF, FT-IR, SEM, TG-DTA, Zeta Potential Meter, Specific Surface Area, and Particle Size Analyzer. The results showed that obtained CMP nano-whiskers have a significantly powder characteristics.

Yao, Nengjian; Zhang, Yin; Kong, Deshuang; Zhu, Jianping; Tao, Yaqiu; Qiu, Tai

2011-10-01

220

Effect of calcium on the oxidation of linoleic acid by potato (Solanum tuberosum var. Desiree) tuber 5-lipoxygenase.  

PubMed

When the effect of calcium on the oxidation of linoleic acid by potato tuber 5-lipoxygenase (LOX) was investigated, it was seen to promote the enzyme's activity at pH values higher than the optimum pH of 6.3, resulting in an enzyme activation at alkaline pH. Kinetic analysis of calcium activation at different pH values revealed that the cation abolished the inhibition by high substrate concentration, which occurs in the absence of Ca(2+), thus leading to activation at high substrate concentration. Studies were conducted to investigate the influence of Ca(2+) on the physicochemical nature of the substrate and its effect on the LOX activity expression. It was concluded that the aggregation mode rather than the aggregation state of linoleic acid is responsible for potato 5-LOX changes. PMID:10691630

López-Nicolás, J M; Bru Martìnez, R; García-Carmona, F

2000-02-01

221

Thermotolerance and antioxidant systems in Agrostis stolonifera: involvement of salicylic acid, abscisic acid, calcium, hydrogen peroxide, and ethylene.  

PubMed

This study investigated whether pre-treating plants with specific putative signaling components and heat acclimation would induce tolerance of a cool-season grass, creeping bentgrass (Agrostis stolonifera var. palustris), to subsequent heat stress and whether thermotolerance induction of those pretreatments was associated with the regulation of antioxidant regenerating enzymes. The treatments included foliar application of salicylic acid (SA), abscisic acid (ABA), calcium chloride (CaCl2), hydrogen peroxide (H2O2), 1-aminocyclopropane-1-carboxylic acid (ACC, a precursor of ethylene prior to the exposure of plants to heat stress (35 degrees C) in a growth chamber. Physiological measurements including turf quality, leaf photosynthetic rate, and levels of oxidative damage demonstrated that all treatments increased heat tolerance. The better heat tolerance for pre-treated plants as compared to controls was related to the protection of oxidative damage under heat stress. APX activity increased over the first 2 days and 5 days of heating for ACC and CaCl2 respectively, but for only 12 h for H2O2. SA and ABA pre-treatments had no effects on APX activity earlier, but maintained APX activity at a significantly higher level than in controls after 24 h of heating. SA and ABA pre-treatments had no effects on POX activity. ACC treatment significantly increased POX activity. Pre-treatment with CaCl2, H2O2, and HA reduced POX activity, particularly during the later phase of heating. Plants treated with SA, CaCl2, H2O2 and HA had lower CAT activity than their control plants prior to heating and within 48 h of heat stress. ABA and ACC pre-treatments maintained higher CAT activity than the controls after 48 h of heating. ACC, CaCl2, or HA pre-treatments increased SOD activity only before 5 days of heat stress. SA and ABA pre-treatments had less effect on APX activity earlier under heat stress. These results suggest that specific groups of potential signaling molecules may induce tolerance of creeping bentgrass to heat stress by reducing oxidative damage. PMID:15128028

Larkindale, Jane; Huang, Bingru

2004-04-01

222

The renin-angiotensin system blockade does not prevent renal interstitial fibrosis induced by aristolochic acids  

Microsoft Academic Search

The renin-angiotensin system blockade does not prevent renal interstitial fibrosis induced by aristolochic acids.BackgroundExperimental aristolochic acid nephropathy (AAN), characterized by interstitial fibrosis, tubular atrophy, and chronic renal failure, was reported after 35-day injections of aristolochic acids (AA) to salt-depleted male Wistar rats. The link between renal fibrosis and the renin-angiotensin system (RAS) in this model remains unknown.MethodsWe investigated the impact

Frederic D. Debelle; Joelle L. Nortier; Cecile P. Husson; Eric G. De Prez; Anne R. Vienne; KATJA ROMBAUT; Isabelle J. Salmon; Monique M. Deschodt-Lanckman; JEAN-LOUIS VANHERWEGHEM

2004-01-01

223

Benidipine, a Long-Acting Calcium-Channel Blocker, Prevents the Progression to End-Stage Renal Failure in a Rat Mesangioproliferative Glomerulonephritis  

Microsoft Academic Search

Background: Although the renoprotective effect of calcium-channel blockers (CCBs) has been examined in several models of hypertensive nephropathy, it remains unclear. It also remains to be clarified whether CCBs prevent the progression to end-stage renal failure in chronic progressive glomerulonephritis (GN). A new rat model of progressive mesangioproliferative GN was used to study the effect of benidipine hydrochloride, a long-acting

Takamichi Nakamura; Jun-ei Obata; Makoto Onitsuka; Yuji Shimada; Yoji Yoshida; Hiroshi Kawachi; Fujio Shimizu

2000-01-01

224

Benidipine, a dihydropyridine–calcium channel blocker, prevents lysophosphatidylcholine-induced injury and reactive oxygen species production in human aortic endothelial cells  

Microsoft Academic Search

Lysophosphatidylcholine (lysoPC) is a component of oxidized low-density lipoproteins (oxLDLs), which play an important role in the pathogenesis of atherosclerosis. In this study, we examined whether benidipine hydrochloride (benidipine), a dihydropyridine–calcium channel blocker with antioxidant activity, prevents lysoPC (C 16:0)-induced injury of human aortic endothelial cells (HAEC). Treatment of HAECs with lysoPC changed cell morphology, decreased cell viability and induced

Masahiro Matsubara; Kazuhide Hasegawa

2005-01-01

225

Synergism of calcium-ethanehydroxybisphosphonate (CaEHBP) and FeC1 3: controlled release polymers for preventing calcification of bioprosthetic aortic wall  

Microsoft Academic Search

Controlled release delivery implants based on ethylene-vinyl acetate (EVA) copolymer were studied for prevention of calcification of aortic wall in an intracirculatory rat allograft model. The calcium salt of ethanehydroxybisphosphonate (CaEHBP) and ferric chloride (FeCl3) were used as anti-calcification drugs either in combination or separately in solvent-cast EVA films. These matrices were characterized in vitro for their drug release at

Narendra R. Vyavahare; Xuan Qu; Michael Lee; Priya Behari; Frederick J. Schoen; Robert J. Levy

1995-01-01

226

Effect of potential renal acid load of foods on urinary citrate excretion in calcium renal stone formers  

Microsoft Academic Search

The aim of this study was to investigate the influence of the potential renal acid load (PRAL) of the diet on the urinary\\u000a risk factors for renal stone formation. The present series comprises 187 consecutive renal calcium stone patients (114 males,\\u000a 73 females) who were studied in our stone clinic. Each patient was subjected to an investigation including a 24-h

Alberto Trinchieri; Renata Lizzano; Federica Marchesotti; Giampaolo Zanetti

2006-01-01

227

Preparation of poly( l-lactic acid)-polysiloxane-calcium carbonate hybrid membranes for guided bone regeneration  

Microsoft Academic Search

A novel poly(l-lactic acid) (PLLA)\\/calcium carbonates hybrid membrane containing polysiloxane was prepared using aminopropyltriethoxysilane (APTES) for biodegradable bone-guided regeneration. Carboxy groups in the PLLA made a chemical bond with amino groups in APTES, resulting in the formation of the hybrid membrane. The polysiloxane-hybridized PLLA was an amorphous phase. The membrane formed hydroxycarbonate apatite (HCA) on its surface after 3d of

Hirotaka Maeda; Toshihiro Kasuga; Larry L. Hench

2006-01-01

228

Changes of intracellular calcium, fatty acids and phospholipids during miltefosine-induced apoptosis monitored by fluorescence- and 13C NMR-spectroscopy.  

PubMed

The alkylphosphocholine Miltefosine (hexadecylphosphocholine, HePC) induces apoptosis in human epithelial KB cells, whereas no such effect can be observed in a resistant clone (KBres). Its mode of action is mediated via the cell membrane, whereas the mechanism is still widely unknown. The use of various spectroscopic methods (fluorescence spectroscopy with Fura-2/AM on viable cells, 13C NMR spectroscopy on lipid extracts) reveals osmotic and metabolic changes in HePC treated sensitive cells. Intracellular free Ca(2+)-concentration increased over 300% of control in apoptotic cells, whereas KBres cells showed only a minor increase and no morphological response typical for apoptosis. The Ca(2+)-influx was mediated via calcium channels in the cell membrane. The HePC-induced influx is prevented by Gd3+, which blocks those calcium channels. Cells, grown in Ca(2+)-free medium, showed no apoptotic behaviour after treatment with HePC. If apoptosis was induced, an increased fatty acid and subsequent phospholipid biosynthesis was observed. This effect seems to be a specific marker of apoptosis in KB cells. PMID:10628349

Henke, J; Engelmann, J; Kutscher, B; Nssner, G; Engel, J; Voegeli, R; Leibfritz, D

229

Inhibition of fatty acid synthase prevents preadipocyte differentiation  

Microsoft Academic Search

Inhibition of fatty acid synthase (FAS) reduces food intake in rodents. As adipose tissue expresses FAS, we sought to investigate the effect of reduced FAS activity on adipocyte differentiation. FAS activity was suppressed either pharmacologically or by siRNA during differentiation of 3T3-L1 cells. Cerulenin (10?M), triclosan (50?M), and C75 (50?M) reduced dramatically visible lipid droplet accumulation, while incorporation of [1-14C]acetate

Bernhard Schmid; Jörg F. Rippmann; Moh Tadayyon; Bradford S. Hamilton

2005-01-01

230

l-Amino acid-sensing by calcium-sensing receptors: A molecular link between protein and calcium metabolism  

Microsoft Academic Search

Dietary protein intake has a major, positive influence on bone health including improved bone mineral density and reductions in fracture-incidence, however, the molecular origins of these effects are unclear. Herein we consider how the release of amino acids from dietary protein appears to provide molecular signals in the gastrointestinal tract as well as the portal and systemic blood and demonstrate

Arthur D. Conigrave; Hiu-Chuen Lok; Hee-Chang Mun

2007-01-01

231

Dairy product, saturated fatty acid, and calcium intake and prostate cancer in a prospective cohort of Japanese men.  

PubMed

Many epidemiologic studies have reported a positive association between dairy products and prostate cancer. Calcium or saturated fatty acid in dairy products has been suspected as the causative agent. To investigate the association between dairy products, calcium, and saturated fatty acid and prostate cancer in Japan, where both the intake of these items and the incidence of prostate cancer are low, we conducted a population-based prospective study in 43,435 Japanese men ages 45 to 74 years. Participants responded to a validated questionnaire that included 138 food items. During 7.5 years of follow-up, 329 men were newly diagnosed with prostate cancer. Dairy products were associated with a dose-dependent increase in the risk of prostate cancer. The relative risks (95% confidence intervals) comparing the highest with the lowest quartiles of total dairy products, milk, and yogurt were 1.63 (1.14-2.32), 1.53 (1.07-2.19), and 1.52 (1.10-2.12), respectively. A statistically significant increase in risk was observed for both calcium and saturated fatty acid, but the associations for these were attenuated after controlling for potential confounding factors. Some specific saturated fatty acids increased the risk of prostate cancer in a dose-dependent manner. Relative risks (95% confidence intervals) on comparison of the highest with the lowest quartiles of myristic acid and palmitic acid were 1.62 (1.15-2.29) and 1.53 (1.07-2.20), respectively. In conclusion, our results suggest that the intake of dairy products may be associated with an increased risk of prostate cancer. PMID:18398033

Kurahashi, Norie; Inoue, Manami; Iwasaki, Motoki; Sasazuki, Shizuka; Tsugane, And Shoichiro

2008-04-01

232

Prevention of Bone Demineralization by Calcium Supplementation in Precocious Puberty during Gonadotropin-Releasing Hormone Agonist Treatment  

Microsoft Academic Search

We have previously demonstrated a negative impact on peak bone mass in girls with precocious puberty treated with GnRH agonist (GnRHa). Several studies have shown that a high calcium intake positively influences bone mass in prepubertal girls and leads to a higher peak bone mass. The aim of this study was to evaluate the effect of calcium supplementation in girls

FRANCO ANTONIAZZI; FRANCESCO BERTOLDO; SILVANA LAURIOLA; STEFANIA SIRPRESI; ELISABETTA GASPERI; GIORGIO ZAMBONI

233

Combined Therapeutic Potential of meso-2,3-Dimercaptosuccinic Acid and Calcium Disodium Edetate on the Mobilization and Distribution of Lead in Experimental Lead Intoxication in Rats  

Microsoft Academic Search

Combined Therapeutic Potential of meso-2,3-Dimercaptosuccinic Acid and Calcium Disodium Edetate on the Mobilization and Distribution of Lead in Experimental Lead Intoxication in Rats. Flora, S. J. S., Bhattacharya, R., and Vijayaraghavan, R. (1995). Fundam. Appl. Toxicol. 25, 233-240.Asymptomatic lead poisoning remains a serious public health problem in developed and developing countries. Chelation therapy particularly with calcium disodium ethelenediamine tetra-acetic acid

S. J. S. Flora; R. Bhattacharya; R. Vijayaraghavan

1995-01-01

234

Viability of Listeria monocytogenes on commercially-prepared hams surface treated with acidic calcium sulfate and lauric arginate and stored at 4 °C  

Microsoft Academic Search

We demonstrated the effectiveness of delivering an antimicrobial purge\\/fluid into shrink-wrap bags immediately prior to introducing the product and vacuum sealing, namely the “Sprayed Lethality In Container” (SLIC™) intervention delivery method. The pathogen was Listeria monocytogenes, the antimicrobials were acidic calcium sulfate (ACS; calcium sulfate plus lactic acid; 1:1 or 1:2 in dH2O) and lauric arginate (LAE; Ethyl-N-dodecanoyl-l-arginate hydrochloride; 5%

J. B. Luchansky; J. E. Call; B. Hristova; L. Rumery; L. Yoder; A. Oser

2005-01-01

235

Calcium aluminate cements in fly ash\\/calcium aluminate blend phosphate cement systems: Their role in inhibiting carbonation and acid corrosion at a low hydrothermal temperature of 90°C  

Microsoft Academic Search

Study was focused upon formulating sodium polyphosphate-modified fly ash\\/calcium aluminate blend (SFCB) geothermal well cements with advanced anti-carbonation and anti-acid corrosive properties. At a low hydrothermal temperature of 90°C, to improve these properties, we investigated the effectiveness of various calcium aluminate cement (CAC) reactants in minimizing the rate of carbonation and in abating the attack of H2SO4 (pH ~ 1.6).

T. Sugama; L. E. Brothers; L. Weber

2002-01-01

236

Meta-analysis of the quantity of calcium excretion associated with the net acid excretion of the modern diet under the acid-ash diet  

Microsoft Academic Search

Background:Theacid-ashdiethypothesisofosteoporosissuggests that acid from the modern diet causes a demineralization of the skeleton, and mobilized bone calcium is excreted. A systematic approachhasnotbeenusedtosummarizethefindingsofthenumer- ous studies about the hypothesis. Objectives: The purpose of this meta-analysis was to estimate the quantityofnetacidexcretionandcalciuriaassociatedwiththemod- erndiet,toassesstheassociationbetweenacidexcretionandcalcium excretion, and to assess the influence of urine preservatives on cal- cium measurement. Design: We systematically searched for trials of the

Tanis R Fenton; Michael Eliasziw; Andrew W Lyon; Suzanne C Tough; David A Hanley

237

Structural and thermotropic properties of calcium-dimyristoylphosphatidic acid complexes at acidic and neutral pH conditions.  

PubMed Central

Two kinds of calcium-dimyristoylphosphatidic acid (DMPA) complexes at acidic and neutral pH conditions were prepared in the following ways. The complex at pH 4 was obtained by adding Ca2+ to DMPA dispersion in pure water. On the other hand, the complex at pH 7.4 was obtained by adding Ca2+ to DMPA dispersion in the presence of NaOH. The stoichiometries of Ca2+ ion to DMPA molecule are 0.5-0.67 and approximately 1 for the complexes at pH 4 and 7.4, respectively. Static x-ray diffraction shows that the hydrocarbon chains of the Ca(2+)-DMPA complex at pH 4 at 20 degrees C are more tightly packed than those of the complex at pH 7.4 at 20 degrees C. Furthermore, the complex at pH 4 at 20 degrees C gives rise to several reflections that might be related to the ordered arrangement of the Ca2+ ions. These results indicate that the structure of the complex at pH 4 is crystalline-like. In the differential scanning calorimetry (DSC) thermogram, the complex at pH 7.4 undergoes no phase transition in a temperature range between 30 and 80 degrees C. On the other hand, in the DSC thermogram for the complex at pH 4, a peak appears at 65.8 degrees C in the first heating scan. In the successive second heating scan, a transition peak appears at 63.5 degrees C. In connection with the DSC results, the structural changes associated with these phase transitions were studied with temperature-scan x-ray diffraction. In the first heating scan, although a peak appears at 65.80C in the DSC thermogram, the hydrocarbon chain packing gradually converts from an orthorhombic lattice to a hexagonal lattice near 52 degree C, and successively the chain melting phase transition occurs near 670C. In the second heating scan, the hydrocarbon chains are packed in a hexagonal lattice over the whole temperature range and the chain melting phase transition occurs near 63.5 degree C. Therefore,the Ca2+-DMPA complex at pH 4 has a metastable state. The metastable state transforms to a stable state by maintaining the complex at pH 4 for about 90 h at 200C.

Takahashi, H.; Yasue, T.; Ohki, K.; Hatta, I.

1995-01-01

238

Fatty acid bile acid conjugates (FABACs)--New molecules for the prevention of cholesterol crystallisation in bile  

PubMed Central

BACKGROUND—Cholesterol gall stones are a frequent disease for which at present surgery is the usual therapy. Despite the importance of bile acids it has become evident that phospholipids are the main cholesterol solubilisers in bile. Even phospholipid components, such as fatty acids, have anticrystallising activity.?AIM—To synthesise fatty acid bile acid conjugates (FABACs) and study their effects on cholesterol crystallisation in bile in vitro and in vivo.?METHODS—FABACs were prepared by conjugation of cholic acid at position 3 with saturated fatty acids of variable chain length using an amide bond. Cholesterol crystallisation and its kinetics (crystal observation time, crystal mass) were studied in model bile, pooled enriched human bile, and fresh human bile using FABACs with saturated fatty acids of varying chain length (C-6 to C-22). Absorption of FABACs into blood and bile was tested in hamsters. Prevention of biliary cholesterol crystallisation in vivo was tested in hamsters and inbred mice.?RESULTS—FABACs strongly inhibited cholesterol crystallisation in model as well as native bile. The FABACs with longer acyl chains (C-16 to C-22) were more effective. At a concentration of 5 mM, FABACs almost completely inhibited cholesterol crystallisation in fresh human bile for 21 days. FABACs were absorbed and found in both portal and heart blood of hamsters. Levels in bile were 2-3 times higher than in blood, indicating active secretion. Appreciable levels were found in the systemic circulation 24-48 hours after a single administration. Ingested FABACs completely prevented the formation of cholesterol crystals in the gall bladders of hamsters and mice fed a lithogenic diet.?CONCLUSIONS—FABACs are potent inhibitors of cholesterol crystallisation in bile. They are absorbed and secreted into bile and prevent the earliest step of cholesterol gall stone formation in animals. These compounds may be of potential use in cholesterol gall stone disease in humans.???Keywords: gall stones; bile; phospholipids; cholesterol crystallisation; fatty acid bile acid conjugates

Gilat, T; Somjen, G; Mazur, Y; Leikin-Frenkel, A; Rosenberg, R; Halpern, Z; Konikoff, F.

2001-01-01

239

Zoledronic Acid for the Treatment and Prevention of Primary and Secondary Osteoporosis  

PubMed Central

There is increasing interest in therapies that can be administered less frequently and/or avoid gastrointestinal irritation. The efficacy of once-yearly zoledronic acid (5 mg) in the treatment and prevention of osteoporosis has been evaluated in different patient populations. In the 3-year HORIZON-Pivotal Fracture Trial in postmenopausal women with osteoporosis, zoledronic acid reduced the risk of vertebral and hip fracture by 70% and 41%, respectively, versus placebo. The efficacy of zoledronic acid in preventing subsequent fracture in patients with a hip fracture was evaluated in the HORIZON-Recurrent Fracture Trial. New vertebral and nonvertebral fractures were significantly reduced by treatment initiated within 90 days of incident hip fracture, without evidence of delayed fracture healing. Data from a 1-year study show that a single zoledronic acid 5-mg infusion is superior to oral risedronate 5 mg/day for treatment and prevention of glucocorticoid-induced osteoporosis. Increases in bone mineral density and decreases in bone turnover markers were significantly greater with zoledronic acid than with risedronate. Two different treatment regimens of zoledronic acid were found to be more effective than placebo for prevention of bone loss in postmenopausal women and reducing markers of bone turnover after 2 years. In conclusion, zoledronic acid 5 mg once-yearly infusion has demonstrated marked efficacy in the treatment and prevention of primary and secondary osteoporosis, with a combination of fracture risk reduction and prevention of bone loss at key sites. It is the only agent shown to reduce the incidence of fracture and mortality in patients with a previous low-trauma hip fracture.

Rizzoli, Rene

2010-01-01

240

Bypassing the rumen in dairy ewes: the reticular groove reflex vs. calcium soap of olive fatty acids.  

PubMed

A 3 x 3 Latin Square experiment was designed to compare 2 ways of bypassing the effects of the rumen with olive oil fatty acids in 'Manchega' dairy ewes. Treatments were a control diet, CaOFA (control diet plus 45 g of olive fatty acids as calcium soap), and OO (control plus 45 g/d of olive fatty acids as olive oil emulsified in skim milk) and bottle-fed to animals trained to maintain the reticular groove reflex). No differences were found in milk, protein, and lactose yields, but fat yield and milk fat content were greater in treatments with added fat (CaOFA and OO). Content of short- and medium-chain fatty acids in milk fat was greater for control treatment than for the other 2 groups, the yield of these fatty acids being similar for all 3 diets, except that of C12:0, which was greater for the control treatment. Content and yield of C18:0 and isomers of C18:1 others than oleic acid were greater in milk from the CaOFA diet than from the other 2 diets. Oleic acid content and yield were greater in milk after OO treatment (23.9% and 16.8 g/d, respectively), intermediate after CaOFA treatment (19.2% and 13.8 g/d, respectively), and lower after control diet (10.7% and 6.52 g/d, respectively). Linoleic acid yield and content were greater in ewes fed the OO diet than in those on the other 2 diets, both of which showed similar data. All these changes indicated that the "protected" olive fatty acids (as calcium soap) were severely affected by the rumen environment and that the use of the reticular groove reflex seems to be a more effective way of bypassing the rumen in adult lactating dairy ewes. PMID:15653540

García, C Dobarganes; Hernández, M Pérez; Cantalapiedra, G; Salas, J M; Merino, J A

2005-02-01

241

Coordination of biologically important alpha-amino acids to calcium(II) at high pH: insights from crystal structures of calcium alpha-aminocarboxylates.  

PubMed

A series of calcium alpha-aminocarboxylates was prepared by refluxing aqueous solutions/suspensions of calcium hydroxide and the respective alpha-amino acid. The colorless, crystalline hydrates Ca(gly)2.H2O (1), Ca(ala)2.3H2O (2), Ca(val)2.H2O (3), Ca(leu)2.3H2O (4), Ca(met)2.nH2O (5, n approximately 2), and Ca(pro)2.H2O (6) have been isolated in yields between 29 and 67% (gly- = glycinate, ala- = rac-alaninate, val- = rac-valinate, leu- = rac-leucinate, met- = rac-methioninate, pro- = rac-prolinate). The compounds 1-6 are readily soluble in water. The 0.10 M solutions have ca. pH 10-11 which is consistent with a noticeable degree of dissociation. The 13C NMR spectra of 1-6 in D2O were measured, and their comparison with those of the corresponding tetramethylammonium alpha-aminocarboxylates point to carboxylate coordination in solution, but no indication of nitrogen coordination was found. Infrared spectra of 1-6 gave similar results for the solid state. Complete single-crystal X-ray structure analyses of 1-4 and preliminary ones of 5 and 6, however, revealed that all aminocarboxylate ligands are N,O-chelating. Crystals of 2 consist of mononuclear complexes, while the other five compounds form three different types of one-dimensional coordination polymers. Structural diversity is also observed with the binding modes of the aminocarboxylate ligands and the calcium environment. Besides terminal aminocarboxylate coordination, there are three different types of aminocarboxylate bridges. The calcium ions are seven- or eight-coordinate in N2O5 and N2O6 coordination environments, respectively; one or three water molecules are part of the first ligand sphere of each metal ion. The crystal structures support conjectures about the existence of the yet undetected solution species [Cax(aa)2x(H2O)n] (aa- = alpha-aminocarboxylate). For example, x = 1 is realized in crystalline [Ca(ala)2(H2O)3] (2), and in 4 [Ca2(leu)4(H2O)4] complexes (x = 2) are linked to infinite chains by bridging aqua ligands. PMID:17257025

Fox, Stefan; Büsching, Insa; Barklage, Walter; Strasdeit, Henry

2007-02-01

242

Lipoic acid prevents development of the hyperdynamic circulation in anesthetized rats with biliary cirrhosis.  

PubMed

Chronic bile duct ligation is associated with the development of oxidant injury, biliary cirrhosis, portal hypertension, and a hyperdynamic circulation. We have previously demonstrated that the hyperdynamic circulation in the partial portal vein-ligated rat can be prevented by the administration of N-acetylcysteine. To extend these findings, we have examined the effect of lipoic acid, a thiol-containing antioxidant, on hemodynamics, oxidative stress, and nitric oxide (NO) production in bile duct-ligated (BDL) cirrhotic rats. Lipoic acid was given continuously in drinking water to normal and BDL rats; control rats received ordinary drinking water, and animals were studied at 24 days following surgery. Lipoic acid prevented the development of the hyperdynamic circulation (cardiac index [CI]: 15.7 +/- 2.0 vs. 29.5 +/- 2.1 mL x min-1 x 100 g-1; P <. 05) and significantly attenuated the rise in portal pressure (PP) (12.7 +/- 0.8 vs. 15.2 +/- 0.5 mm Hg; P <.05). Hepatic nitric oxide synthase (NOS) activity and plasma nitrite/nitrate concentration increased significantly following bile duct ligation, and both of these were prevented by lipoic acid. Lipoic acid had no effect on the biochemical or histological parameters of liver function in the cirrhotic group. We conclude that lipoic acid prevents the development of the hyperdynamic circulation in the rat model of biliary cirrhosis, and that this is associated with decreased synthesis of NO. PMID:10216116

Marley, R; Holt, S; Fernando, B; Harry, D; Anand, R; Goodier, D; Davies, S; Moore, K

1999-05-01

243

Bioefficacy of a novel calcium-potassium salt of (-)-hydroxycitric acid.  

PubMed

Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (-)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind of Garcinia cambogia, has been reported to promote body fat loss in humans without stimulating the central nervous system. The level of effectiveness of G. cambogia extract is typically attributed solely to HCA. However, other components by their presence or absence may significantly contribute to its therapeutic effectiveness. Typically, HCA used in dietary weight loss supplement is bound to calcium, which results in a poorly soluble (<50%) and less bioavailable form. Conversely, the structural characteristics of a novel Ca2+/K+ bound (-)-HCA salt (HCA-SX or Super CitriMax) make it completely water soluble as well as bioavailable. An efficacious dosage of HCA-SX (4500 mg/day t.i.d.) provides a good source of Ca2+ (495 mg, 49.5% of RDI) and K+ (720 mg, 15% of RDI). Ca2+ ions are involved in weight management by increasing lipid metabolism, enhancing thermogenesis, and increasing bone density. K+, on the other hand, increases energy, reduces hypertension, increases muscle strength and regulates arrhythmias. Both Ca and K act as buffers in pH homeostasis. HCA-SX has been shown to increase serotonin availability, reduce appetite, increase fat oxidation, improve blood lipid levels, reduce body weight, and modulate a number of obesity regulatory genes without affecting the mitochondrial and nuclear proteins required for normal biochemical and physiological functions. PMID:16055158

Downs, Bernard W; Bagchi, Manashi; Subbaraju, Gottumukkala V; Shara, Michael A; Preuss, Harry G; Bagchi, Debasis

2005-08-01

244

Efficacy of a novel calcium/potassium salt of (-)-hydroxycitric acid in weight control.  

PubMed

The weight-loss efficacy of a novel, water-soluble, calcium-potassium salt of (-)-hydroxycitric acid (HCA-SX) was re-examined in 90 obese subjects (BMI: 30-50.8 kg/m2). We combined data from two previously reported randomized, double-blind, placebo-controlled clinical studies in order to achieve a better statistical evaluation based on a larger population. This re-examination of data also allowed us to reflect more intensely on various aspects of weight loss studies. Subjects were randomly divided into three groups: group A received a daily dose of HCA-SX 4, 667 mg (providing 2,800 mg HCA per day); group B was given a daily dose of a combination of HCA-SX 4,667 mg, niacin-bound chromium (NBC) 4 mg (providing 400 microg elemental chromium), and Gymnema sylvestre extract (GSE) 400 mg (providing 100 mg gymnemic acid); and group C received a placebo in three equally divided doses 30-60 min before each meal. All subjects were provided a 2,000 kcal diet/day and participated in a supervised walking program for 30 min/day, 5 days/week. Eighty-two subjects completed the study. At the end of 8 weeks, in group A, both body weight and BMI decreased by 5.4%, low-density lipoprotein and triglycerides levels were reduced by 12.9% and 6.9%, respectively, while high-density lipoprotein levels increased by 8.9%, serum leptin levels decreased by 38%, serotonin levels increased by 44.5% and urinary excretion of fat metabolites increased by 32-109%. Group B demonstrated similar beneficial changes, but generally to a greater extent. No significant adverse effects were observed. The combined results confirm that HCA-SX and, to a greater degree, the combination of HCA-SX plus NBC and GSE reduce body weight and BMI, suppress appetite, improve blood lipid profiles, increase serum leptin and serotonin levels and increase fat oxidation more than placebo. We conclude that dosage levels, timing of administration, subject compliance and bioavailability of HCA-SX significantly affect results and that when taken as directed, HCA-SX is a highly effective adjunct to healthy weight control. PMID:16366421

Preuss, H G; Garis, R I; Bramble, J D; Bagchi, D; Bagchi, M; Rao, C V S; Satyanarayana, S

2005-01-01

245

Glycosaminoglycan stimulation of calcium release from mouse calvariae. Specificity for hyaluronic acid and dermatan sulfate  

Microsoft Academic Search

Summary  Heparin in combination with suboptimal concentrations of parathyroid hormone (PTH) has been shown to stimulate calcium release\\u000a from bone organ cultures. The mechanism of action of heparin, however, is not known. One possible mechanism relates to the\\u000a highly sulfated structure of heparin. We have compared heparin to other glycosaminoglycans to stimulate calcium release from\\u000a mouse calvarial organ cultures in the

David L. Cochran

1987-01-01

246

Oleic Acid Prevents Detrimental Effects of Saturated Fatty Acids on Bovine Oocyte  

Microsoft Academic Search

Mobilization of fatty acids from adipose tissue during\\u000ametabolic stress will increase the amount of free fatty acids in\\u000ablood and follicular fluid and, thus, may affect oocyte quality. In\\u000athis in vitro study, the three predominant fatty acids in follicular\\u000afluid (saturated palmitic and stearic acid and unsaturated oleic\\u000aacid) were presented to maturing oocytes to test whether fatty

H. Aardema; P. L. A. M. Vos; F. Lolicato; B. A. J. Roelen; H. M. Knijn; A. B. Vaandrager; J. B. Helms; B. M. Gadella

2011-01-01

247

Recovery of calcium carbonate from waste gypsum and utilization for remediation of acid mine drainage from coal mines.  

PubMed

The recovery of calcium carbonate from waste gypsum (a waste product of the reverse osmosis (RO) desalination process) was tested using sodium carbonate. Batch recovery of calcium carbonate from waste gypsum slurries by reacting with sodium carbonate under ambient conditions was used to assess the technical feasibility of CaCO(3) recovery and its use for pre-treatment of acid mine drainage (AMD) from coal mines. The effect of key process parameters, such as the slurry concentration (%) and the molar ratio of sodium carbonate to gypsum were considered. It was observed that batch waste gypsum conversion significantly increased with decrease in the slurry concentration or increase in the molar ratio of sodium carbonate to gypsum. The CaCO(3) recovered from the bench-scale batch reactor demonstrated effective neutralization ability during AMD pre-treatment compared with commercial laboratory grade CaCO(3). PMID:22828309

Mulopo, J; Radebe, V

2012-01-01

248

Gallic acid prevents lysosomal damage in isoproterenol induced cardiotoxicity in Wistar rats  

Microsoft Academic Search

This study was aimed to evaluate the preventive effect of gallic acid on lysosomal enzymes in isoproterenol treated myocardial infarcted rats. Male albino Wistar rats were pretreated with gallic acid (15 mg\\/kg) daily for a period of 10 days. After the treatment period, isoproterenol (100 mg\\/kg) was subcutaneously injected to rats twice at an interval of 24 h. The activity of creatine kinase-MB and

Ponnian Stanely Mainzen Prince; Hansi Priscilla; Periathambi Thangappan Devika

2009-01-01

249

Prevention of volatile fatty acids production and limitation of odours from winery wastewaters by denitrification  

Microsoft Academic Search

The effect of the addition of nitrate to winery wastewaters to control the formation of VFA in order to prevent odours during storage and treatment was studied in batch bioreactors at different NO3\\/chemical oxygen demand (COD) ratios and at full scale in natural evaporation ponds (2×7000m2) by measuring olfactory intensity. In the absence of nitrate, butyric acid (2304mgL?1), acetic acid

André Bories; Jean-Michel Guillot; Yannick Sire; Marie Couderc; Sophie-Andréa Lemaire; Virginie Kreim; Jean-Claude Roux

2007-01-01

250

Preventing neural tube defects: The importance of periconceptional folic acid supplements  

Microsoft Academic Search

Objective: To inform the obstetrician-gynecologist of recent scientific evidence regarding the use of supplemental folic acid for prevention of neural tube defects (NTDs).Data Sources: We selected English language articles via MEDLINE published from January 1990 through February 1997, using the search terms “folic acid” and “neural tube defect.” Additional sources were identified through cross-referencing and through searching selected journals published

GregoryJ Locksmith; Patrick Duff

1998-01-01

251

Effects of lactic acid and glycolic acid on human osteoblasts: a way to understand PLGA involvement in PLGA/calcium phosphate composite failure.  

PubMed

The use of degradable composite materials in orthopedics remains a field of intense research due to their ability to support new bone formation and degrade in a controlled manner, broadening their use for orthopedic applications. Poly (lactide-co-glycolide) acid (PLGA), a degradable biopolymer, is now a popular material for different orthopedic applications and is proposed for use in tissue engineering scaffolds either alone or combined with bioactive ceramics. Interference screws composed of calcium phosphates and PLGA are readily available in the market. However, some reports highlight problems of screw migration or aseptic cyst formation following screw degradation. In order to understand these phenomena and to help to improve implant formulation, we have evaluated the effects of PLGA degradation products: lactic acid and glycolic acid on human osteoblasts in vitro. Cell proliferation, differentiation, and matrix mineralization, important for bone healing were studied. It was found that the toxicity of polymer degradation products under buffering conditions was limited to high concentrations. However, non-toxic concentrations led to a decrease in cell proliferation, rapid cell differentiation, and mineralization failure. Calcium, whilst stimulating cell proliferation was not able to overcome the negative effects of high concentrations of lactic and glycolic acids on osteoblasts. These effects help to explain recently reported clinical failures of calcium phosphate/PLGA composites, but further in vitro analyses are needed to mimic the dynamic situation which occurs in the body by, for example, culture of osteoblasts with materials that have been pre-degraded to different extents and thus be able to relate these findings to the degradation studies that have been performed previously. PMID:22105618

Meyer, Florent; Wardale, John; Best, Serena; Cameron, Ruth; Rushton, Neil; Brooks, Roger

2011-11-21

252

The Ability of PAS, Acetylsalicylic Acid and Calcium Disodium EDTA to Protect Against the Toxic Effects of Manganese on Mitochondrial Respiration in Gill of Crassostrea virginica.  

PubMed

Manganese (Mn) is an essential metal that at excessive levels in brain causes Manganism, a condition similar to Parkinson's disease. Previously we showed that Mn had a neurotoxic effect on the dopaminergic, but not serotonergic, innervation of the lateral ciliated cells in the gill of the Eastern Oyster, Crassostrea virginica. While the mechanism of action of Mn toxicity is not completely understood, studies suggest that Mn toxicity may involve mitochondrial damage and resulting neural dysfunction in the brain's dopaminergic system. In this study we utilized micro-batch chambers and oxygen probes to measure oyster gill mitochondrial respiration in the presence of Mn and potential Mn blockers. The addition of Mn to respiring mitochondria caused a dose dependent decrease in mitochondrial O(2) consumption. Pretreating mitochondria with calcium disodium EDTA (caEDTA), p aminosalicylic acid (PAS) or acetylsalicylic acid (ASA) before Mn additions, provided full protection against the toxic effects of Mn. While mitochondrial pretreatment with any of the 3 drugs effectively blocked Mn toxicity, none of the drugs tested was able to reverse the decrease in mitochondrial O(2) consumption seen in Mn treated mitochondria. The study found that high levels of Mn had a toxic effect on gill mitochondrial O(2) consumption and that this effect could be blocked by the drugs caEDTA, PAS and ASA. C. virginica continues to be a good model with which to investigate the mechanism that underlies manganese neurotoxcity and in the pharmacological study of drugs to treat or prevent Manganism. PMID:21977482

Crawford, Sherine; Davis, Kiyya; Saddler, Claudette; Joseph, Jevaun; Catapane, Edward J; Carroll, Margaret A

2011-01-01

253

The Ability of PAS, Acetylsalicylic Acid and Calcium Disodium EDTA to Protect Against the Toxic Effects of Manganese on Mitochondrial Respiration in Gill of Crassostrea virginica  

PubMed Central

Manganese (Mn) is an essential metal that at excessive levels in brain causes Manganism, a condition similar to Parkinson's disease. Previously we showed that Mn had a neurotoxic effect on the dopaminergic, but not serotonergic, innervation of the lateral ciliated cells in the gill of the Eastern Oyster, Crassostrea virginica. While the mechanism of action of Mn toxicity is not completely understood, studies suggest that Mn toxicity may involve mitochondrial damage and resulting neural dysfunction in the brain’s dopaminergic system. In this study we utilized micro-batch chambers and oxygen probes to measure oyster gill mitochondrial respiration in the presence of Mn and potential Mn blockers. The addition of Mn to respiring mitochondria caused a dose dependent decrease in mitochondrial O2 consumption. Pretreating mitochondria with calcium disodium EDTA (caEDTA), p aminosalicylic acid (PAS) or acetylsalicylic acid (ASA) before Mn additions, provided full protection against the toxic effects of Mn. While mitochondrial pretreatment with any of the 3 drugs effectively blocked Mn toxicity, none of the drugs tested was able to reverse the decrease in mitochondrial O2 consumption seen in Mn treated mitochondria. The study found that high levels of Mn had a toxic effect on gill mitochondrial O2 consumption and that this effect could be blocked by the drugs caEDTA, PAS and ASA. C. virginica continues to be a good model with which to investigate the mechanism that underlies manganese neurotoxcity and in the pharmacological study of drugs to treat or prevent Manganism.

Crawford, Sherine; Davis, Kiyya; Saddler, Claudette; Joseph, Jevaun; Catapane, Edward J.; Carroll, Margaret A.

2011-01-01

254

SATURATED PICRIC ACID PREVENTS AUTOPHAGIA AND SELF-MUTILATION IN LABORATORY RATS  

Microsoft Academic Search

The dysesthesia and paresthesia that occurs in laboratory rats after spinal cord injury (SCI) results in autophagia. This self-destructive behavior interferes with functional assessments in designed studies and jeopardizes the health of the injured rat. In this study, we evaluated role of saturated picric acid in the prevention of autophagia and self-mutilation. All rats were anesthetized with an intraperitoneal injection

V. Rahimi-Movaghar; A. Yazdi; S. Saadat

255

Prevention of Tissue Injury and Postsurgical Adhesions by Precoating Tissues with Hyaluronic Acid Solutions  

Microsoft Academic Search

The effectiveness of inhibiting serosal tissue damage and preventing surgical adhesions by precoating tissues with dilute solutions of hyaluronic acid (HA) was evaluated in a rat cecal abrasion model. This study was performed at three independent laboratories using the same protocol. Three hundred and seventy-five adult rats were divided into five treatment groups (125 animals at each study site): 0.1%

James W. Burns; Kevin Skinner; Jude Colt; Aviva Sheidlin; Roderick Bronson; Yoseph Yaacobi; Eugene P. Goldberg

1995-01-01

256

Partitioning of polyunsaturated fatty acids, which prevent cardiac arrhythmias, into phospholipid cell membranes  

Microsoft Academic Search

It has been demonstrated in animal studies that polyunsaturated fatty acids (PUFA) prevent ischemia- induced malignant ventricular arrhythmias, a major cause of sudden cardiac death in humans. To learn how these PUFA, at low micromolar concentrations, exert their antiar- rhythmic activity, we studied their effects in vitro on the contractions of isolated cardiac myocytes and the conduc- tances of their

Eric M. Pound; Jing X. Kang; A. Leaf

257

Prevention and Termination of ?-Adrenergic Agonist-Induced Arrhythmias by Free Polyunsaturated Fatty Acids in Neonatal Rat Cardiac Myocytes  

Microsoft Academic Search

Polyunsaturated omega-3 fatty acids, which have been shown to prevent ischemia-induced ventricular fibrillation in prepared dogs, were tested in cultured neonatal rat cardiac myocytes for their ability to prevent the tachyarrhythmias induced by isoproterenol, a ?-adrenergic agonist. We found that polyunsaturated fatty acids (5-10 ?M), especially the fish oil omega-3 fatty acids, but not monouunsaturated and saturated fatty acids were

J. X. Kang; A. Leaf

1995-01-01

258

Impacts of calcium signal transduction on the fermentation production of antitumor ganoderic acids by medicinal mushroom Ganoderma lucidum.  

PubMed

Recently signal transduction engineering of secondary metabolism is receiving great interest as a powerful tool towards efficient production of valuable secondary metabolites. This work found that the calcineurin-signal transduction was significant to triterpene biosynthesis by higher fungus (mushroom). Addition of calcium ion (at 10mM) to static liquid cultures of Ganoderma lucidum, a famous traditional medicinal mushroom, was proved as a useful strategy to enhance the production of antitumor ganoderic acids (GAs), which resulted in 3.7-, 2.6-, 4.5-, 3.2- and 3.8-fold improvement of total GAs, individual GA-Mk, -T, -S, and -Me, respectively. Experiments using Ca2+ sensor inhibitors indicated the involvement of calcineurin signal in regulating GAs biosynthesis. Quantitative gene transcription analysis revealed that the expression levels of genes of GAs biosynthesis and Ca2+ sensor were up-regulated with calcium addition while down-regulated under the inhibitors addition, suggesting that higher GAs production may be resulted from higher expressions of those genes. Based on the results obtained, a possible model on the effect of external calcium ion on the GAs biosynthesis via calcineurin signal transduction pathway was proposed. PMID:22036615

Xu, Yi-Ning; Zhong, Jian-Jiang

2011-10-18

259

Prevention of recurrent nephrolithiasis.  

PubMed

The first episode of nephrolithiasis provides an opportunity to advise patients about measures for preventing future stones. Low fluid intake and excessive intake of protein, salt and oxalate are important modifiable risk factors for kidney stones. Calcium restriction is not useful and may potentiate osteoporosis. Diseases such as hyperparathyroidism, sarcoidosis and renal tubular acidosis should be considered in patients with nephrolithiasis. A 24-hour urine collection with measurement of the important analytes is usually reserved for use in patients with recurrent stone formation. In these patients, the major urinary risk factors include hypercalciuria, hyperoxaluria, hypocitraturia and hyperuricosuria. Effective preventive and treatment measures include thiazide therapy to lower the urinary calcium level, citrate supplementation to increase the urinary citrate level and, sometimes, allopurinol therapy to lower uric acid excretion. Uric acid stones are most often treated with citrate supplementation. Data now support the cost-effectiveness of evaluation and treatment of patients with recurrent stones. PMID:10593318

Goldfarb, D S; Coe, F L

1999-11-15

260

Effects of zoledronic acid and ibandronic acid on renal functions and calcium, phosphorus and alkaline phosphatase levels in breast cancer patients with bone metastases: a retrospective analysis  

PubMed Central

Aim of the study Bone is a common site of metastasis in patients with breast cancer. Skeletal complications associated with bone metastasis are commonly treated with bisphosphonates. However, there are a number of side-effects associated with these, such as renal failure, hypocalcemia and osteonecrosis of the jaw. We aimed to determine the effects of ibandronic and zoledronic acid on serum creatinine (SCr), calcium (Ca), phosphorus (P), alkaline phosphatase (ALP) and estimated glomerular filtration rates (eGFR). The objective was to determine the safety of these bisphosphonates, especially zoledronic acid. Material and methods Forty-one patients diagnosed with breast cancer (all with bone metastasis) were enrolled. We retrospectively evaluated bisphosphonate type, duration of treatment, infusion time and the parameters SCr, Ca, P, ALP and eGFR. Results Nineteen patients were included in the zoledronic acid group and 22 in the ibandronic acid group. Mean age in the ibandronic acid group was 53.27 ±11.01, and 53.26 ±9.98 in the zoledronic acid group. Median duration of administration in the ibandronic acid group was 11 (7-37) months, and 10 (7-57) months in the zoledronic acid group. SCr levels did not change significantly during the study period. Pre- and post-treatment Ca levels were also unchanged, but serum ALP levels in the ibandronic acid group and P levels in the zoledronic acid decreased after the final administration; eGFR was unchanged by the end of the study. Conclusions Zoledronic and ibandronic acid are safe modalities in the treatment of skeletal events in breast cancer patients with bone metastasis.

Yildiz, Bulent; Kavgaci, Halil; Ozdemir, Feyyaz; Aydin, Fazil

2012-01-01

261

Efficacy of homocysteine lowering therapy with folic acid in stroke prevention: a meta-analysis  

PubMed Central

Background and Purpose Although lower serum homocysteine concentration is associated with a reduced risk of stroke in epidemiologic studies, randomized controlled trials (RCTs) have yielded mixed findings regarding the effect of therapeutic homocysteine lowering on stroke prevention. We performed a meta-analysis of RCTs to assess the efficacy of folic acid supplementation in the prevention of stroke. Methods Salient trials were identified by formal literature search. Relative risk (RR) with 95% confidence interval (CI) was used as a measure of the association between folic acid supplementation and risk of stroke, pooling data across trials using a fixed-effects model. Results The search identified 13 RCTs of folic acid therapy to reduce homocysteine, enrolling 39,005 participants, in which stroke was reported as an outcome measure. Across all trials, folic acid supplementation was associated with a trend toward mild benefit that did not reach statistical significance in reducing the risk of stroke (RR 0.93, 95% CI 0.85-1.03; p=0.16). The RR for non-secondary prevention trials was 0.89 (95% CI 0.79-0.99; p=0.03). In stratified analyses, a greater beneficial effect was seen in the trials testing combination therapy of folic acid plus vitamins B6 and B12 (RR 0.83, 0.71-0.97; p=0.02) and in the trials which disproportionately enrolled male patients (men/women > 2, RR 0.84, 0.74-0.94; p=0.003). Conclusions Folic acid supplementation did not demonstrate a major effect in averting stroke. However, potential mild benefits in primary stroke prevention, especially when folate is combined with B vitamins and in male patients, merit further investigation.

Lee, Meng; Hong, Keun-Sik; Chang, Shen-Chih; Saver, Jeffrey L.

2010-01-01

262

Net energy for lactation of calcium salts of long-chain fatty acids for cows fed silage-based diets.  

PubMed

The NEL of calcium salts of long-chain fatty acids from palm oil was determined in mature Holstein cows. Twelve lactating (fed for ad libitum intake) and six nonlactating (restricted to near maintenance intake) Holstein cows were fed 0 or 2.95% fat supplement in diets formulated to contain 16 or 20% CP in a 2 x 2 factorial arrangement of treatments in a single reversal design within protein level. The fat supplement was substituted for ground corn and minerals. Two 6-d total collection balance trials were conducted during which cows were in open circuit respiration chambers. Intake of OM was lower for lactating cows fed the fat supplement (18.1 vs. 19.1 kg/d), but energy intake did not differ (93.2 Mcal/d). Total long-chain fatty acid intake was increased from 477 to 820 g/d with fat feeding. Apparent digestibility of long-chain fatty acids was increased 11.1 percentage units with increased dietary CP for lactating cows with no difference in fatty acid digestibility for the dry cows. Milk yield was higher (34.3 vs. 32.0 kg/d) with fat feeding, but milk energy yield did not differ (22.6 Mcal/d). The NEL of the fat supplement was estimated from the incremental differences in energy values within cows, assuming NEL of corn replaced by fat to be 1.96 Mcal/kg DM, and was determined to be 6.52 Mcal/kg DM (SE = 1.74). The efficiency of the use of metabolizable energy for lactation from dietary fat was 77.2%. The energy in calcium salts of long-chain fatty acids is utilized efficiently for lactation in mature cows. PMID:1655843

Andrew, S M; Tyrrell, H F; Reynolds, C K; Erdman, R A

1991-08-01

263

Effect of dietary calcium on the colonic luminal environment.  

PubMed Central

Dietary supplementation with calcium may prevent the development of colorectal cancer. This mechanism may be related to fatty acid and bile salt chelation in the small bowel forming non-toxic calcium-soap compounds. Calcium may also act locally or systemically on the colonic mucosa. Faecal concentrations of free fatty acids and free bile acids were measured in 17 Sprague-Dawley rats (weighing 472 (39 g)) whose daily calcium intake had been trebled by enriching the chow and adding calcium lactate (24 g/l) to the drinking water. Mean (SEM) faecal concentrations of free bile acids were 33% less than in 19 controls (1.23 (0.15) v 1.82 (0.20) mg/g; p less than 0.001), whereas free fatty acid concentrations were 117% higher (14.68 (3.59) v 6.76 (2.41) mg/g; p less than 0.02). The 'direct' effect of calcium was assessed by organ culture of rat colonic explants in three different concentrations of calcium. Crypt cell production rate (measured by a stathmokinetic technique), which was (mean (SEM)) 4.80 (0.23) cells/crypt/h in control medium (Ca2+ = 2.14 mmol/l), fell by 43% when calcium concentration was doubled (p less than 0.05) and by a further 43% when the concentration was trebled (p less than 0.02). Calcium binds free fatty acids but not free bile acids intraluminally. Calcium has a direct antitropic action on colonic crypts. Images Figure 1

Appleton, G V; Owen, R W; Wheeler, E E; Challacombe, D N; Williamson, R C

1991-01-01

264

Anomalous Phospholipid n-6 Polyunsaturated Faffy Acid Composition in Idiopathic Calcium Nephrolithiasi  

Microsoft Academic Search

Anomalies in the erythrocyte transport of anions and cations have been described in idiopathic calcium oxalate nephrolithiasis and seem to play a pathoge- netic role in this disease. In consideration of the hypothesis that the complex array of ion flux cell abnormalities is an epiphenomenon of an anomaly in the composition of cell membranes, this study investigated cell-membrane lipid composition.

Bruno Baggio; Giovanni Gambaro; Sabina Zambon; Francesco Marchini; Andrea Bassi; Luciana Bordin; Giulio Clan; Enzo Manzato

265

Water, sulfur dioxide and nitric acid adsorption on calcium carbonate: a transmission and ATR-FTIR study.  

PubMed

Calcium carbonate (CaCO3) is a reactive component of mineral dust aerosol as well as buildings, statues and monuments. In this study, attenuated total reflection (ATR) and transmission Fourier transform infrared spectroscopy (FTIR) have been used to study the uptake of water, sulfur dioxide and nitric acid on CaCO3 particles at 296 K. Under atmospheric conditions, CaCO3 particles are terminated by a Ca(OH)(CO3H) surface layer. In the presence of water vapor between 5 and 95% relative humidity (RH), water molecularly adsorbs on the Ca(OH)(CO3H) surface resulting in the formation of an adsorbed thin water film. The adsorbed water film assists in the enhanced uptake of sulfur dioxide and nitric acid on CaCO3 in several ways. Under dry conditions (near 0% RH), sulfur dioxide and nitric acid react with the Ca(OH)(CO3H) surface to form adsorbed carbonic acid (H2CO3) along with sulfite and nitrate, respectively. Adsorbed carbonic acid is stable on the surface under vacuum conditions. Once the surface saturates with a carbonic acid capping layer, there is no additional uptake of gas-phase sulfur dioxide and nitric acid. However, upon adsorption of water, carbonic acid dissociates to form gaseous carbon dioxide and there is further uptake of sulfur dioxide and nitric acid. In addition, adsorbed water increases the mobility of the ions at the surface and enhances uptake of SO2 and HNO3. In the presence of adsorbed water, CaSO3 forms islands of a crystalline hydrate whereas Ca(NO3)2 forms a deliquescent layer or micropuddles. Thus adsorbed water plays an important and multi-faceted role in the uptake of pollutant gases on CaCO3. PMID:19791344

Al-Hosney, H A; Grassian, V H

2005-03-21

266

[Comparative study of defibrotide and calcium heparin in the prevention of postoperative deep venous thrombosis. A randomized multicenter study].  

PubMed

The efficacy and tolerability of defibrotide (800 mg/i.v.) and calcium heparin (15,000 UI/s.c.) in the prophylaxis of post-surgical deep venous thrombosis (DVT) and pulmonary embolism (PE) were compared in a multicentre trial involving 60 Italian surgical institutions (general surgery, obstetrics and gynecology, urology). Total enrollment was 2,250 patients (defibrotide: 1.194; calcium heparin 1.056). According to the protocol, the clinical suspicion of DVT and/or PE led to in-depth diagnostic evaluations (DVT: Doppler ultrasound velocimetry; PE: chest X-rays; ECG, pulmonary scintigraphic scanning). The incidence of post-surgical DVT was similar in the two groups (defibrotide: 8 patients; calcium heparin: 10 patients). A trend towards a lower incidence of DVT in the defibrotide group no PE; calcium heparin: 4 cases (chi 2 = 4.530, p less than 0.05). The local and systemic tolerability of both treatment was excellent. This trial, carried out in routine surgical practice, establishes the profibrinolytic approach to DVT prophylaxis as a sound and effective alternative to the traditional interference with the coagulation cascade. PMID:3050616

Battistel, V; De Rosa, A

1988-09-01

267

Ursodeoxycholic Acid in the Prevention of Gallstone Formation after Bariatric Surgery: A Meta-analysis  

Microsoft Academic Search

Background  Rapid weight loss increases risk for gallstone formation. Prophylactic cholecystectomy is difficult. Several small trials\\u000a have shown that ursodeoxycholic acid (UDCA) may prevent gallstone formation after bariatric surgery. The aim of this study\\u000a is to assess the efficacy and safety of UDCA in the prevention of gallstone formation after bariatric surgery.\\u000a \\u000a \\u000a \\u000a Methods  Electronic databases, including the Cochrane Central Register of Controlled

Manley C. Uy; Marilyn C. Talingdan-Te; Wendell Z. Espinosa; Ma. Lourdes O. Daez; Janus P. Ong

2008-01-01

268

Calcium supplementation: cardiovascular risk?  

PubMed

Adequate dietary calcium intake and appropriate sunlight exposure ensuring adequate vitamin D availability are basic measures for the prevention of osteoporosis. Calcium and vitamin D supplementation increases bone density. Vitamin D plus calcium supplementation prevents hip fractures and other nonvertebral fractures in institutionalised persons 70 years of age or older. A meta-analysis of clinical trials showed an increase in myocardial infarction in patients taking calcium supplementation alone, with a relative risk of about 1.3. Epidemiological studies have not shown an increase in the cardiovascular risk. Conflicting results have also been reported in postmenopausal women taking both calcium and vitamin D. In an epidemiological study, hypercalcaemia was associated with increased mortality, particularly cardiovascular mortality. In practice, caution dictates that not all patients should routinely take calcium and vitamin D supplements. When calcium supplements are nonetheless used, the dose should be adjusted to dietary intake in order to avoid hypercalcaemia. PMID:23866352

2013-06-01

269

Hyaluronic acid stimulates the formation of calcium phosphate on CoCrMo alloy in simulated physiological solution.  

PubMed

The behaviour of CoCrMo alloy has been studied in two simulated physiological solutions-NaCl and Hanks' solutions-each containing the sodium salt of hyaluronic acid. Hyaluronic acid is a component of synovial joint fluid, so the behaviour of orthopaedic alloys in its presence needs to be assessed. Electrochemical methods, X-ray photoelectron spectroscopy and scanning electron microscopy have been used to analyse the composition, thickness and morphology of any layers formed on the alloy. The addition of hyaluronic acid shifts the corrosion potential and increases the value of polarization resistance. The presence of hyaluronic acid in simulated Hanks' physiological solution stimulates the formation of a calcium phosphate layer, opening up the possibility for tailoring the surface properties of CoCrMo alloy. The viability of human osteoblast-like was determined using the Alamar(®) Blue Assay, while the osteogenic activity was evaluated by alkaline phosphatase activity. The presence of hyaluronic acid affects the alkaline phosphatase activity. PMID:23250579

Milošev, Ingrid; Hmeljak, Julija; Cör, Andrej

2012-12-19

270

Folic acid supplementation prevents phenytoin-induced gingival overgrowth in children  

PubMed Central

Objective: Gingival overgrowth is an important adverse effect of phenytoin (PHT) therapy, occurring in about half of the patients. This study aimed to evaluate the effect of oral folic acid supplementation (0.5 mg/day) for the prevention of PHT-induced gingival overgrowth (PIGO) in children with epilepsy aged 6–15 years on PHT monotherapy for 6 months. Methods: This was a randomized, double-blind, placebo-controlled trial conducted at a tertiary level hospital from May 2008 to June 2009. Children aged 6–15 years started on PHT monotherapy within last 1 month were eligible for inclusion. Preexisting gingival overgrowth, use of other folic acid antagonists, and macrocytic anemia were exclusion criteria. Trial subjects were randomized to receive either folic acid or placebo. The primary outcome measure was incidence of any degree of gingival overgrowth after 6 months of PHT monotherapy. The trial was registered with clinicaltrials.gov (NCT00781196). Results: A total of 120 children were recruited, 62 and 58, respectively, in folic acid and placebo arms. The 2 arms were comparable at baseline. Twenty-one percent of patients in the folic acid arm developed PIGO, as compared with 88% receiving placebo (p < 0.001). Absolute risk reduction of PIGO by folic acid was 67% (95% confidence interval 54%–80%), and relative risk reduction was 0.76. Conclusions: Oral folic acid was found to decrease the incidence of PIGO in children on PHT monotherapy, in a statistically significant and clinically relevant manner. Classification of evidence: This study provides Class I evidence that folic acid supplementation, 0.5 mg/day, is associated with prevention of gingival overgrowth in children taking PHT monotherapy.

Arya, R.; Kabra, M.; Sahu, J.K.; Kalra, V.

2011-01-01

271

Dehydration of aliphatic alcohols on phosphoric acid catalyst with the addition of calcium phosphate  

Microsoft Academic Search

The kinetic regularities of dehydration of sec- and tert-butyl alcohols on a catalyst consisting of a mixture of calcium phosphate and HâPOâ, deposited on molten quartz were studied by pulsed gas chromatography. At an equal water vapor pressure in the system, the activity of a catalyst consisting of a pure HâPOâ is higher than that of a catalyst with the

P. A. Obraztsov; O. E. Batalin; V. S. Malinskii; L. F. Shubenok; M. I. Vinnik

1986-01-01

272

Influence of acid-base changes on the intracellular calcium concentration of neurons in primary culture  

Microsoft Academic Search

The influence of changes in intra- and extracellular pH (pHi and pHe, respectively) on the cytosolic, free calcium concentration ([Ca2+]i) of neocortical neurons was studied by microspectrofluorometric techniques and the fluorophore fura-2. When, at constant pHe, pHi was lowered with the NH4Cl prepulse technique, or by a transient increase in CO2 tension, [Ca2+]i invariably increased, the magnitude of the rise

Y. B. OuYang; P. Mellergård; T. Kristián; V. Kristiánova; B. K. Siesjö

1994-01-01

273

Calcium- and polyphosphate-containing acidic granules of sea urchin eggs are similar to acidocalcisomes, but are not the targets for NAADP  

PubMed Central

Acidocalcisomes are acidic calcium-storage compartments described from bacteria to humans and characterized by their high content in poly P (polyphosphate), a linear polymer of many tens to hundreds of Pi residues linked by high-energy phosphoanhydride bonds. In the present paper we report that millimolar levels of short-chain poly P (in terms of Pi residues) and inorganic PPi are present in sea urchin extracts as detected using 31P-NMR, enzymatic determinations and agarose gel electrophoresis. Poly P was localized to granules randomly distributed in the sea urchin eggs, as shown by labelling with the poly-P-binding domain of Escherichia coli exopolyphosphatase. These granules were enriched using iodixanol centrifugation and shown to be acidic and to contain poly P, as determined by Acridine Orange and DAPI (4?,6?-diamidino-2-phenylindole) staining respectively. These granules also contained large amounts of calcium, sodium, magnesium, potassium and zinc, as detected by X-ray microanalysis, and bafilomycin A1-sensitive ATPase, pyrophosphatase and exopolyphosphatase activities, as well as Ca2+/H+ and Na+/H+ exchange activities, being therefore similar to acidocalcisomes described in other organisms. Calcium release from these granules induced by nigericin was associated with poly P hydrolysis. Although NAADP (nicotinic acid–adenine dinucleotide phosphate) released calcium from the granule fraction, this activity was not significantly enriched as compared with the NAADP-stimulated calcium release from homogenates and was not accompanied by poly P hydrolysis. GPN (glycyl-L-phenylalanine-naphthylamide) released calcium when added to sea urchin homogenates, but was unable to release calcium from acidocalcisome-enriched fractions, suggesting that these acidic stores are not the targets for NAADP.

Ramos, Isabela B.; Miranda, Kildare; Pace, Douglas A.; Verbist, Katherine C.; Lin, Fu-Yang; Zhang, Yonghui; Oldfield, Eric; Machado, Ednildo A.; De Souza, Wanderley; Docampo, Roberto

2010-01-01

274

Calcium- and polyphosphate-containing acidic granules of sea urchin eggs are similar to acidocalcisomes, but are not the targets for NAADP.  

PubMed

Acidocalcisomes are acidic calcium-storage compartments described from bacteria to humans and characterized by their high content in poly P (polyphosphate), a linear polymer of many tens to hundreds of Pi residues linked by high-energy phosphoanhydride bonds. In the present paper we report that millimolar levels of short-chain poly P (in terms of Pi residues) and inorganic PPi are present in sea urchin extracts as detected using 31P-NMR, enzymatic determinations and agarose gel electrophoresis. Poly P was localized to granules randomly distributed in the sea urchin eggs, as shown by labelling with the poly-P-binding domain of Escherichia coli exopolyphosphatase. These granules were enriched using iodixanol centrifugation and shown to be acidic and to contain poly P, as determined by Acridine Orange and DAPI (4',6'-diamidino-2-phenylindole) staining respectively. These granules also contained large amounts of calcium, sodium, magnesium, potassium and zinc, as detected by X-ray microanalysis, and bafilomycin A1-sensitive ATPase, pyrophosphatase and exopolyphosphatase activities, as well as Ca2+/H+ and Na+/H+ exchange activities, being therefore similar to acidocalcisomes described in other organisms. Calcium release from these granules induced by nigericin was associated with poly P hydrolysis. Although NAADP (nicotinic acid-adenine dinucleotide phosphate) released calcium from the granule fraction, this activity was not significantly enriched as compared with the NAADP-stimulated calcium release from homogenates and was not accompanied by poly P hydrolysis. GPN (glycyl-L-phenylalanine-naphthylamide) released calcium when added to sea urchin homogenates, but was unable to release calcium from acidocalcisome-enriched fractions, suggesting that these acidic stores are not the targets for NAADP. PMID:20497125

Ramos, Isabela B; Miranda, Kildare; Pace, Douglas A; Verbist, Katherine C; Lin, Fu-Yang; Zhang, Yonghui; Oldfield, Eric; Machado, Ednildo A; De Souza, Wanderley; Docampo, Roberto

2010-08-01

275

Prevention of autoimmune diabetes by immunogene therapy using recombinant vaccinia virus expressing glutamic acid decarboxylase  

Microsoft Academic Search

Aims\\/hypotheses. Type I (insulin-dependent) diabetes mellitus results from T-cell-mediated autoimmune destruction of pancreatic beta cells. Among the beta-cell autoantigens that have been implicated in triggering of beta-cell-specific autoimmunity, glutamic acid decarboxylase (GAD) is a strong candidate in both humans and the NOD mouse. We aimed to determine whether treatment with a recombinant vaccinia virus expressing GAD (rVV-GAD65) could prevent the

H.-S. Jun; Y.-H. Chung; J. Han; A. Kim; S. Yoo; R. Sherwin; J.-W. Yoon

2002-01-01

276

Prevention of ischemia-induced cardiac Sudden death by n?3 polyunsaturated fatty acids in dogs  

Microsoft Academic Search

The objective of this study was to obtain functional information associated with the prevention by n?3 polyunsaturated fatty\\u000a acids (PUFA) of ischemia-induced fatal cardiac ventricular arrhythmias in the intact, conscious, exercising dog. Thirteen\\u000a dogs suceptible to ischemia-induced ventricular fibrillation were prepared surgically by ligation of their anterior descending\\u000a left coronary artery and placement of an inflatable cuff around their left

George E. Billman; Jing X. Kang; Alexander Leaf

1997-01-01

277

Complex Forming Properties of Natural Occurring Fulvic Acids. Part 1. Complexes with Cadmium, Copper and Calcium.  

National Technical Information Service (NTIS)

The experimental program developed in our earlier investigations of the protonation equilibria encountered with Armadale Horizons Bh and Suwannee River fulvic-acid has been employed in the present investigation of a Swedish fulvic acid source. Complicatio...

J. A. Marinsky A. Mathuthu M. Bicking J. Ephraim

1985-01-01

278

Role of Calcium Independent Phospholipase A 2 in Maintaining Mitochondrial Membrane Potential and Preventing Excessive Exocytosis in PC12 Cells  

Microsoft Academic Search

This study was carried out to elucidate the effects of calcium independent phospholipase A2 (iPLA2) on mitochondrial function and exocytosis in neuroendocrine cells. iPLA2 mRNA and protein were detected in cell lysates and mitochondria from PC12 cells. Treatment of cells with the iPLA2 inhibitor, bromoenol lactone (BEL), resulted in reduction in the mitochondrial membrane potential. Increase in membrane capacitance\\u000a and

May-Thu Ma; Jin-Fei Yeo; Akhlaq A. Farooqui; Wei-Yi Ong

2011-01-01

279

Biotransformation of dehydroabietic acid with resting cell suspensions and calcium alginate-immobilized cells of Mortierella isabellina.  

PubMed Central

Mortierella isabellina ATCC 38063 is a zygomycete capable of hydroxylating fish-toxic resin acids which occur in certain pulp mill effluents to nontoxic metabolites. Addition of dehydroabietic acid (1) (80 mg/liter) to a freshly inoculated culture of M. isabellina in dextrose-yeast extract broth resulted in precursor disappearance in 28 to 30 h. During growth phase, hydroxylation occurred at C-2, whereas hydroxylation at C-15 and C-16 commenced with onset of stationary phase. Alternatively, 1 added to stationary-phase culture (40 mg/liter) disappeared within 2 h and hydroxylation occurred concurrently at C-2, C-15, and C-16. Enzymatic activity of stationary-phase culture was totally cell associated and was present despite the absence of 1 during the preparatory growth phase. Resuspension of mature fungi as free mycelia or immobilized in calcium alginate beads did not diminish the effectiveness of the biotransformation, although two new metabolites, 15-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (5) and 16-hydroxy-8,9,11,12-tetradehydro-7,8-dihydroabietic acid (7) were formed. Immobilized mycelia retained hydroxylase activity for greater than 110 days whether or not they were challenged with fresh 1 on a regular basis. In this respect they are more long-lived than resuspended free mycelia are.

Kutney, J P; Choi, L S; Hewitt, G M; Salisbury, P J; Singh, M

1985-01-01

280

Influence of acid-base changes on the intracellular calcium concentration of neurons in primary culture.  

PubMed

The influence of changes in intra- and extracellular pH (pHi and pHe, respectively) on the cytosolic, free calcium concentration ([Ca2+]i) of neocortical neurons was studied by microspectrofluorometric techniques and the fluorophore fura-2. When, at constant pHe, pHi was lowered with the NH4Cl prepulse technique, or by a transient increase in CO2 tension, [Ca2+]i invariably increased, the magnitude of the rise being proportional to delta pHi. Since similar results were obtained in Ca(2+)-free solutions, the results suggest that the rise in [Ca2+]i was due to calcium release from intracellular stores. The initial alkaline transient during NH4Cl exposure was associated with a rise in [Ca2+]i. However, this rise seemed to reflect influx of Ca2+ from the external solution. Thus, in Ca(2+)-free solution NH4Cl exposure led to a decrease in [Ca2+]i. This result and others suggest that, at constant pHe, intracellular alkalosis reduces [Ca2+]i, probably by enhancing sequestration of calcium. When cells were exposed to a CO2 transient at reduced pHe, Ca2+ rose initially but then fell, often below basal values. Similar results were obtained when extracellular HCO3- concentration was reduced at constant CO2 tension. Unexpectedly, such results were obtained only in Ca(2+)-containing solutions. In Ca(2+)-free solutions, acidosis always raised [Ca2+]i. It is suggested that a lowering of pHe stimulates extrusion of Ca2+ by ATP-driven Ca2+/2H+ antiport. PMID:7843312

OuYang, Y B; Mellergård, P; Kristián, T; Kristiánova, V; Siesjö, B K

1994-01-01

281

[Alpha-tocopherol and alpha-lipoic acid. An antioxidant synergy with potential for preventive medicine].  

PubMed

Reactive oxygen species (ROS) have been involved in the induction and progression of damage of many human disorders, such as: heart infarction, cerebral ischemia, diabetic neuropathy, Alzheimer's disease, etc. In several studies, the synergism between alpha-lipoic acid and vitamin E has been described and potent antioxidant effects can be obtained when both antioxidants are simultaneously used. This review highlights recent findings showing that the combination of alpha-lipoic acid plus vitamin E effectively reduces oxidative damage in brain and cardiac ischemia as well as in other pathological events related to ROS increasing. These antioxidants are present in a broad variety of foods, are also available in several dietary supplements and their side effects are very rare. Therefore, alpha-lipoic acid and vitamin E may play an important role in clinical preventive medicine and human nutrition. PMID:18589588

González-Pérez, Oscar; Moy-López, Norma Angélica; Guzmán-Muñiz, Jorge

282

Folic acid for prevention of neural tube defects: pediatric anticipatory guidance.  

PubMed

The incidence of neural tube defects including myelomeningocele, which is one of the most common causes of infant and childhood disability, can be substantially reduced by folic acid supplementation to the diet of women before and during the early stages of pregnancy. All females of childbearing age should be taking folic acid supplements of 0.4 mg/day (400 micrograms/day) and consuming a diet rich in folate. Because many pregnancies are unplanned, supplementation should not await plans for pregnancy. Because pediatric nurse practitioners are in frequent contact with both adolescent patients and patients whose mothers are of childbearing age, and because pediatric nurse practitioners have an interest in preventing neural tube defects in future pediatric patients, they are in a good position to provide the necessary anticipatory guidance regarding the critical need for adequate folic acid intake by females of childbearing age. This article discusses and includes guidelines for providing this anticipatory guidance. PMID:9592437

Morrow, J D; Kelsey, K

283

The Marine Sponge-Derived Polyketide Endoperoxide Plakortide F Acid Mediates Its Antifungal Activity by Interfering with Calcium Homeostasis? §  

PubMed Central

Plakortide F acid (PFA), a marine-derived polyketide endoperoxide, exhibits strong inhibitory activity against the opportunistic fungal pathogens Candida albicans, Cryptococcus neoformans, and Aspergillus fumigatus. In the present study, transcriptional profiling coupled with mutant and biochemical analyses were conducted using the model organism Saccharomyces cerevisiae to investigate the mechanism of action of this compound. PFA elicited a transcriptome response indicative of a Ca2+ imbalance, affecting the expression of genes known to be responsive to altered cellular calcium levels. Several additional lines of evidence obtained supported a role for Ca2+ in PFA's activity. First, mutants lacking calcineurin and various Ca2+ transporters, including pumps (Pmr1 and Pmc1) and channels (Cch1 and Mid1), showed increased sensitivity to PFA. In addition, the calcineurin inhibitors FK506 and cyclosporine strongly enhanced PFA activity in wild-type cells. Furthermore, PFA activated the transcription of a lacZ reporter gene driven by the calcineurin-dependent response element. Finally, elemental analysis indicated a significant increase in intracellular calcium levels in PFA-treated cells. Collectively, our results demonstrate that PFA mediates its antifungal activity by perturbing Ca2+ homeostasis, thus representing a potentially novel mechanism distinct from that of currently used antifungal agents.

Xu, Tao; Feng, Qin; Jacob, Melissa R.; Avula, Bharathi; Mask, Melanie M.; Baerson, Scott R.; Tripathi, Siddharth K.; Mohammed, Rabab; Hamann, Mark T.; Khan, Ikhlas A.; Walker, Larry A.; Clark, Alice M.; Agarwal, Ameeta K.

2011-01-01

284

The use of folic acid for the prevention of birth defects in Puerto Rico  

PubMed Central

Introduction The occurrence of neural tube defects (NTD) has been shown to vary by race/ethnicity, with the highest rates among women of Hispanic ethnicity. Women of reproductive age are advised to use folic acid to prevent NTD and other birth defects. Since 1994, Puerto Rico has a campaign to promote the use of folic acid and since 1998 there is fortification of enriched grain products. After fortification, there has been a reduction in the incidence of NTD in the island. The objective of this study is to assess the use of folic acid by women of reproductive age in Puerto Rico and determine factors associated to its use. Methods A self-administered questionnaire was answered by 964 women around the island. Results Folic acid consumption was reported by 30% of the participants, 21% reported to consume it at least 4 times per week, and only 14% consumed it the day before the survey. Knowledge about the recommendation for women to consume folic acid was reported by 97% of the participants. The use of folic acid was lower among women of lower education and lower social class. Women with higher education were 8.3 times more likely to consume folic acid. Conclusion The folic acid campaign has improved women’s knowledge about the recommendation for folic acid supplementation. Nevertheless, its use is lower than desired to continue reducing the incidence of birth defects in Puerto Rico. Education and social class continue to represent barriers to eliminate the disparities in the pre-conception health of our population.

Garcia-Fragoso, Lourdes; Garcia-Garcia, Ines; Rivera, Cynthia E.

2009-01-01

285

Polished rice as natural sources of cancer-preventing geranylgeranoic acid  

PubMed Central

Geranylgeranoic acid, a 20-carbon polyprenoic acid (all-trans 3,7,11,15-tetramethyl-2,4,6,10,14-hexadecatetraenoic acid) and its derivatives were previously developed as synthetic “acyclic retinoids” for cancer chemoprevention. Recently, we demonstrated the natural occurrence of geranylgeranoic acid in various medicinal herbs (Shidoji and Ogawa, 2004). In this present study, we present several lines of evidence to demonstrate that geranylgeranyl diphosphate taken in foods could be metabolized to GGA through geranylgeraniol and geranylgeranyl aldehyde via the following steps: 1) The conversion from geranylgeranyl diphosphate to geranylgeraniol was demonstrated to occur by the action of bovine intestinal alkaline phosphatase, with a Km of 46.1 µM. 2) Geranylgeraniol oxidase-mediated conversion of geranylgeraniol to geranylgeranyl aldehyde was revealed in rat liver homogenates, which activity was mainly localized in the mitochondrial fraction. The mitochondrial enzyme showed a Km of 92.9 µM. 3) The conversion of geranylgeranyl aldehyde to geranylgeranoic acid by geranylgeranyl aldehyde dehydrogenase in rat liver homogenates was absolutely dependent on exogenously added NAD+ or NADP+. The Km of the mitochondrial geranylgeranyl aldehyde dehydrogenase was 27.5 µM for geranylgeranyl aldehyde. Taken together, our data suggest that cancer preventive geranylgeranoic acid could be a physiological metabolite from commonly consumed foods.

Muraguchi, Takashi; Okamoto, Kyoko; Mitake, Maiko; Ogawa, Hiroko; Shidoji, Yoshihiro

2011-01-01

286

Poly(acrylic acid) modified calcium phosphate cements: the effect of the composition of the cement powder and of the molecular weight and concentration of the polymeric acid.  

PubMed

Polymer modified calcium phosphate cements made with cement powders of varying tetracalcium phosphate [TTCP] content were prepared using two different molecular weight fractions of poly(acrylic acid) at four different concentrations. The ratio of the precursors (TTCP:DCPA) in the cement powder was found to influence the initial setting which decreased with increasing concentration of TTCP in the powder phase. It was also observed that cements derived from the higher molecular weight containing PAA yielded significantly (P < 0.05) shorter initial setting time (Ti) than cements containing the lower molecular weight, poly(acrylic acid) [GE7 PAA] The effect of the varying the TTCP content in the three different cement types PCPC-A, PCPC-B and PCPC-C showed that the trends of the compressive strength were specific to the concentration and molecular weight of the poly (acrylic acid). A 20% concentration of Glascol-E7 with a cement powder composed of an equimolar ratio of precursors (PCPC-B) resulted in optimal compressive strength within the range investigated. The TTCP content of the cement powder could also be varied to improve the diametral tensile strengths of the cements; the specific effects however, were again governed by both the concentration and molecular weight of the constituent poly (acrylic acid). The influence of TTCP on both the initial setting time and diametral tensile strength was related to the Ca (2+) ion concentration, which determined the rate and amount of cross-linking in the cement. PMID:17522964

Majekodunmi, A O; Deb, S

2007-05-24

287

Dietary protein and bone health: roles of amino acid-sensing receptors in the control of calcium metabolism and bone homeostasis.  

PubMed

In this article, we review the evidence that dietary protein has a positive influence on bone health, reduces hip fracture risk, and promotes postfracture recovery, and we consider the molecular, cellular, and endocrine bases of the interactions that link protein and calcium metabolism, including effects via IGF-1 and PTH. In addition, we consider the roles of amino acid-sensing mechanisms in coupling dietary protein intake to metabolic change as well as the central role of calcium-sensing receptors (CaRs) in the control of calcium metabolism. Finally, we consider how recently identified broad-spectrum amino acid-sensing receptors from class 3 of the G-protein coupled receptor superfamily including, remarkably, the CaR itself may contribute to the impact of dietary protein on bone. PMID:18466091

Conigrave, A D; Brown, E M; Rizzoli, R

2008-01-01

288

Aberrant Ca(2+) signalling through acidic calcium stores in pancreatic acinar cells.  

PubMed

Pancreatic acinar cells possess a very large Ca(2+) store in the endoplasmic reticulum, but also have extensive acidic Ca(2+) stores. Whereas the endoplasmic reticulum is principally located in the baso-lateral part of the cells, although with extensions into the granular area, the acidic stores are exclusively present in the apical part. The two types of stores can be differentiated pharmacologically because the endoplasmic reticulum accumulates Ca(2+) via SERCA pumps, whereas the acidic pools require functional vacuolar H(+) pumps in order to maintain a high intra-organellar Ca(2+) concentration. The human disease acute pancreatitis is initiated by trypsinogen activation in the apical pole and this is mostly due to either complications arising from gall bladder stones or excessive alcohol consumption. Attention has therefore been focussed on assessing the acute effects of bile acids as well as alcohol metabolites. The evidence accumulated so far indicates that bile acids and fatty acid ethyl esters - the non-oxidative products of alcohol and fatty acids - exert their pathological effects primarily by excessive Ca(2+) release from the acidic stores. This occurs by opening of the very same release channels that are also responsible for normal stimulus-secretion coupling, namely inositol trisphosphate and ryanodine receptors. The inositol trisphosphate receptors are of particular importance and the results of gene deletion experiments indicate that the fatty acid ethyl esters mainly utilize sub-types 2 and 3. PMID:21435718

Petersen, O H; Gerasimenko, O V; Tepikin, A V; Gerasimenko, J V

2011-03-23

289

Magnetic resonance spectroscopy studies on changes in cerebral calcium and zinc and the energy state caused by excitotoxic amino acids.  

PubMed

Under control conditions, superfused hippocampal slices exhibited a significantly higher phosphocreatine (PCr)/ATP ratio than cortical slices; the evidence suggests that this is due to lower concentrations of ATP, rather than higher concentrations of PCr. Glutamate caused relatively rapid decreases in PCr and ATP levels to approximately 45%, accompanied or immediately followed by an increased free intracellular calcium concentration ([Ca2+]i) and the release of Zn2+ in the cortex. In the hippocampus PCr and ATP decreased further to approximately 20% of control values, but the changes in [Ca2+]i and Zn2+ content were slower. This is in contrast to the effects of depolarisation, which produced the same rapid changes in the energy state and [Ca2+]i, with no detectable Zn2+, in both tissues. NMDA causes effects similar to those of glutamate in the cortex (decreases in the energy state, increased [Ca2+]i, and release of Zn2+). Pretreatment of the cortex for 1 h with the NMDA blocker MK-801 prevented all of the observed effects of NMDA. In contrast, pretreatment with MK-801 had no detectable effect on the increase in [Ca2+]i or the decreases in PCr and ATP caused by glutamate, although it prevented the release of zinc. The results are discussed in relation to the function of the NMDA subtype of glutamate receptor in excitotoxicity. PMID:10349857

Thatcher, N M; Prior, M J; Morris, P G; Bachelard, H S

1999-06-01

290

Prevention of cultured rat stellate cell transformation and endothelin-B receptor upregulation by retinoic acid.  

PubMed

1 Physiologically, perisinusoidal hepatic stellate cells (HSC) are quiescent and store retinoids. During liver injury and in cell culture, HSC transform into proliferating myofibroblast-like cells that express alpha-smooth muscle actin (alpha-sma) and produce excessive amounts of extracellular matrix. During transformation (also known as activation), HSC are depleted of the retinoid stores, and their expression of the endothelin-1 (ET-1) system is increased. ET-1 causes contraction of transformed HSC and is implicated in their proliferation and fibrogenic activity. In order to understand the association between retinoids, ET-1 and the activation of HSC, we investigated the effect of 13-cis-retinoic acid on the transformation of cultured HSC and the expression of ET-1 system. 2 HSC derived from normal rat liver were maintained for 10-12 days in a medium supplemented with 5% serum and containing 2.5 micro M retinoic acid without or with 50 nM ET-1 (ETA+ETB agonist) or sarafotoxin S6c (ETB agonist). In another set of experiments, cells treated for 10-12 days with vehicle (ethanol) or retinoic acid were challenged with ET-1 or sarafotoxin S6c, and various determinations were made at 24 h. 3 Retinoic acid inhibited transformation and proliferation of HSC as assessed by morphological characteristics, expression of alpha-sma, bromodeoxyuridine incorporation and cell count. Retinoic acid also prevented upregulation of ETB receptors without affecting ET-1 or ETA expression. Total protein synthesis ([(3)H]leucine incorporation), collagen alpha types I mRNA expression and collagen synthesis ([(3)H]proline incorporation) were lower in retinoic acid-treated cells. Although ET-1-treated cells were morphologically similar to the control cells, their expression of alpha-smooth muscle actin was significantly inhibited. The presence of retinoic acid in the medium during treatment with ET-1 caused further reduction in the expression of alpha-smooth muscle actin. ET-1 and sarafotoxin S6c stimulated total protein synthesis in vehicle- and retinoic acid-treated cells, but collagen synthesis only in the latter. 4 These results showing prevention of HSC activation and negative regulation of ETB receptor expression in them by retinoic acid may have important pathophysiologic implications. PMID:12813000

Chi, Xuedong; Anselmi, Kristin; Watkins, Simon; Gandhi, Chandrashekhar R

2003-06-01

291

Removal of Toxic Metals from Leachates from Hazardous Solid Wastes and Reduction of Toxicity to Microtox by the Use of Calcium Alginate Beads Containing Humic Acid  

Microsoft Academic Search

Improper disposal of hazardous wastes can lead to release of potentially harmful substances through leaching such as heavy metals, which ultimately contaminate soil, sediment surface water, and groundwater through runoff. To remove these toxic metals and avoid any adverse effect on the ecosystem, a novel approach involving calcium alginate (CA) beads containing humic acid (HA) was used. For this, 10%

Ashok K. Pandey; Shri Dhar Pandey; Virendra Misra

2002-01-01

292

Proof for a Nonproteinaceous Calcium-Selective Channel in Escherichia coli by Total Synthesis from (R)-3-hydroxybutanoic Acid and Inorganic Polyphosphate  

Microsoft Academic Search

Traditionally, the structure and properties of natural products have been determined by total synthesis and comparison with authentic samples. We have now applied this procedure to the first nonproteinaceous ion channel, isolated from bacterial plasma membranes, and consisting of a complex of poly(3-hydroxybutyrate) and calcium polyphosphate. To this end, we have now synthesized the 128-mer of hydroxybutanoic acid and prepared

Sudipto Das; Urs D. Lengweiler; Dieter Seebach; Rosetta N. Reusch

1997-01-01

293

Prevention by Means of Fluoride of Enamel Erosion as Caused by Soft Drinks and Orange Juice  

Microsoft Academic Search

Fluoride has been suggested to prevent erosion of the teeth, either after a topical treatment of the teeth or by addition of fluoride to the acidic drink. The main aim of the present study was to describe the dissolution of calcium fluoride in some soft drinks and orange juice and compare it with the amounts of calcium fluoride left on

M. J. Larsen

2001-01-01

294

Method of repressing the precipitation of calcium fluozirconate  

Microsoft Academic Search

Boric acid or a borate salt is added to aqueous solutions of fluoride ; containing radioactive wastes generated during the reprocessing of zirconium ; alloy nuclear fuels which are to be converted to solid form by calcining in a ; fluidized bed. The addition of calcium nitrate to the aqueous waste solutions to ; prevent fluoride volatility during calcination, causes

B. J. Newby; D. W. Rhodes

1973-01-01

295

Effect of Addition of Citric Acid and Casein Phosphopeptide-Amorphous Calcium Phosphate to a Sugar-Free Chewing Gum on Enamel Remineralization in situ  

Microsoft Academic Search

Casein phosphopeptide-amorphous calcium phosphate (CPP-ACP) has been shown to remineralize enamel subsurface lesions in situ. The aim of this study was to investigate the effects of CPP-ACP in a fruit-flavoured sugar-free chewing gum containing citric acid on enamel remineralization, and acid resistance of the remineralized enamel, using an in situ remineralization model. The study utilized a double-blind, randomized, crossover design

F. Cai; D. J. Manton; P. Shen; G. D. Walker; K. J. Cross; Y. Yuan; C. Reynolds; E. C. Reynolds

2007-01-01

296

Curcumin restores Nrf2 levels and prevents quinolinic acid-induced neurotoxicity.  

PubMed

Neurological diseases comprise a group of heterogeneous disorders characterized by progressive brain dysfunction and cell death. In the next years, these diseases are expected to constitute a world-wide health problem. Because excitotoxicity and oxidative stress are involved in neurodegenerative diseases, it becomes relevant to describe pharmacological therapies designed to activate endogenous cytoprotective systems. Activation of transcription factor Nrf2 stimulates cytoprotective vitagenes involved in antioxidant defense. In this work, we investigated the ability of the antioxidant curcumin to induce transcription factor Nrf2 in a neurodegenerative model induced by quinolinic acid in rats. Animals were administered with curcumin (400 mg/kg, p.o.) for 10 days, and then intrastriatally infused with quinolinic acid (240 nmol) on day 10 of treatment. Curcumin prevented rotation behavior (6 days post-lesion), striatal morphological alterations (7 days post-lesion) and neurodegeneration (1 and 3 days post-lesion) induced by quinolinic acid. Curcumin also reduced quinolinic acid-induced oxidative stress (measured as protein carbonyl content) at 6 h post-lesion. The protective effects of curcumin were associated to its ability to prevent the quinolinic acid-induced decrease of striatal intra-nuclear Nrf2 levels (30 and 120 min post-lesion), and total superoxide dismutase and glutathione peroxidase activities (1 day post-lesion). Therefore, results of this study support the concept that neuroprotection induced by curcumin is associated with its ability to activate the Nrf2 cytoprotective pathway and to increase the total superoxide dismutase and glutathione peroxidase activities. PMID:22704781

Carmona-Ramírez, Iván; Santamaría, Abel; Tobón-Velasco, Julio C; Orozco-Ibarra, Marisol; González-Herrera, Irma G; Pedraza-Chaverrí, José; Maldonado, Perla D

2012-06-15

297

Doubling the number of women consuming vitamin supplement pills containing folic acid: An urgently needed birth defect prevention complement to the folic acid fortification of cereal grains  

Microsoft Academic Search

The major known environmental causes of birth defects are ancient agents that have been in the environment for centuries but have been only recently discovered—rubella, alcohol, and folic acid deficiency. In the United States, we have made great progress in preventing congenital rubella syndrome. We also have a great opportunity to prevent spina bifida and anencephaly (SBA) by increasing the

Godfrey P Oakley

1997-01-01

298

Unsaturated fatty acids prevent activation of NLRP3 inflammasome in human monocytes/macrophages.  

PubMed

The NLRP3 inflammasome is involved in many obesity-associated diseases, such as type 2 diabetes, atherosclerosis, and gouty arthritis, through its ability to induce interleukin (IL)-1? release. The molecular link between obesity and inflammasome activation is still unclear, but free fatty acids have been proposed as one triggering event. Here we reported opposite effects of saturated fatty acids (SFAs) compared with unsaturated fatty acids (UFAs) on NLRP3 inflammasome in human monocytes/macrophages. Palmitate and stearate, both SFAs, triggered IL-1? secretion in a caspase-1/ASC/NLRP3-dependent pathway. Unlike SFAs, the UFAs oleate and linoleate did not lead to IL-1? secretion. In addition, they totally prevented the IL-1? release induced by SFAs and, with less efficiency, by a broad range of NLRP3 inducers, including nigericin, alum, and monosodium urate. UFAs did not affect the transcriptional effect of SFAs, suggesting a specific effect on the NLRP3 activation. These results provide a new anti-inflammatory mechanism of UFAs by preventing the activation of the NLRP3 inflammasome and, therefore, IL-1? processing. By this way, UFAs might play a protective role in NLRP3-associated diseases. PMID:24006511

L'homme, Laurent; Esser, Nathalie; Riva, Laura; Scheen, André; Paquot, Nicolas; Piette, Jacques; Legrand-Poels, Sylvie

2013-09-03

299

Ketogenic Essential Amino Acids Modulate Lipid Synthetic Pathways and Prevent Hepatic Steatosis in Mice  

PubMed Central

Background Although dietary ketogenic essential amino acid (KAA) content modifies accumulation of hepatic lipids, the molecular interactions between KAAs and lipid metabolism are yet to be fully elucidated. Methodology/Principal Findings We designed a diet with a high ratio (E/N) of essential amino acids (EAAs) to non-EAAs by partially replacing dietary protein with 5 major free KAAs (Leu, Ile, Val, Lys and Thr) without altering carbohydrate and fat content. This high-KAA diet was assessed for its preventive effects on diet-induced hepatic steatosis and whole-animal insulin resistance. C57B6 mice were fed with a high-fat diet, and hyperinsulinemic ob/ob mice were fed with a high-fat or high-sucrose diet. The high-KAA diet improved hepatic steatosis with decreased de novo lipogensis (DNL) fluxes as well as reduced expressions of lipogenic genes. In C57B6 mice, the high-KAA diet lowered postprandial insulin secretion and improved glucose tolerance, in association with restored expression of muscle insulin signaling proteins repressed by the high-fat diet. Lipotoxic metabolites and their synthetic fluxes were also evaluated with reference to insulin resistance. The high-KAA diet lowered muscle and liver ceramides, both by reducing dietary lipid incorporation into muscular ceramides and preventing incorporation of DNL-derived fatty acids into hepatic ceramides. Conclusion Our results indicate that dietary KAA intake improves hepatic steatosis and insulin resistance by modulating lipid synthetic pathways.

Kimura, Yoshiko; Aleman, Jose O.; Young, Jamey D.; Koyama, Naoto; Kelleher, Joanne K.; Takahashi, Michio; Stephanopoulos, Gregory

2010-01-01

300

Overexpression of PDZ1 domain prevents apoptosis of rat hippocampal neurons induced by kainic acid.  

PubMed

In our previous studies, Tat-GluR6-9c (a glutamate receptor 6 C-terminus peptide fused the TAT protein transduction sequence) not only inhibited the activation of MLK3 (mixed lineage kinase 3) and JNK (c-Jun N-terminal kinase) via the GluR6.PSD-95 (postsynaptic density protein 95).MLK3 signaling module but also diminished neuronal death induced by kainic acid or transient cerebral ischemia in rat hippocampus. Here, we investigate whether overexpression of the PDZ1 domain of PSD-95 protein could suppress the binding of GluR6 with PSD-95 and the activation of MLK3, MKK7 (mitogen-activated kinase kinase 7) and JNK1/2, and rescused neuronal cell death induced by kainic acid. Our results showed that overexpression of the PDZ1 domain of PSD-95 protein could prevent nuclear accumulation and abrogate neuronal cell death in SD (Sprague-Dawley) rat hippocampal neuronal cells. Further studies indicated that overexpression of PDZ1 could inhibit the enhancement of binding of GluR6 to PSD-95 and prevent the activation of MLK3, MKK7 and JNK1/2 induced by kainic acid. Taken together, the essential role of the PDZ1 domain of PSD-95 in apoptotic cell death in neurons provides an experimental foundation for gene therapy of neurodegenerative diseases with overexpression of the PDZ1 domain. PMID:19477222

Hu, Shu-Qun; Zong, Yan-Yan; Fan, Le-Ming; Zhang, Guang-Yi

2009-05-27

301

Nutritional interventions to prevent and treat osteoarthritis. Part I: focus on fatty acids and macronutrients.  

PubMed

Osteoarthritis (OA) is the most common cause of musculoskeletal disability in elderly individuals, and it places an enormous economic burden on society. Management of OA is primarily focused on palliative relief by using agents such as nonsteroidal anti-inflammatory drugs and analgesics. However, such an approach is limited by a narrow therapeutic focus that fails to address the progressive and multimodal nature of OA. Given the favorable safety profile of most nutritional interventions, identifying disease-modifying nutritional agents capable of improving symptoms and also preventing, slowing, or even reversing the degenerative process in OA should remain an important paradigm in translational and clinical research. Applying advances in nutritional science to musculoskeletal medicine remains challenging, given the fluid and dynamic nature of the field, along with a rapidly developing regulatory climate over manufacturing and commerce requirements. The aim of this article is to review the available literature on effectiveness and potential mechanism of macronutrients for OA, with a focus on the following: long-chain ?-3 essential fatty acids eicosapentaenoic acid and docosahexaenoic acid, functional ?-6 fatty acid ?-linolenic acid, and macronutrient composition of background diet. There also is a discussion about the concept of rational polysupplementation via the strategic integration of multiple nutraceuticals with potential complementary mechanisms for improving outcomes in OA. As applied nutritional science evolves, it will be important to stay on the forefront of proteomics, metabolomics, epigenetics, and nutrigenomics, because they hold enormous potential for developing novel therapeutic and prognostic breakthroughs in many areas of medicine, including OA. PMID:22632694

Lopez, Hector L

2012-05-01

302

Prevention of Fatal Arrhythmias in High-Risk Subjects by Fish Oil n-3 Fatty Acid Intake  

Microsoft Academic Search

Background—The long-chain n-3 fatty acids in fish have been demonstrated to have antiarrhythmic properties in experimental models and to prevent sudden cardiac death in a randomized trial of post-myocardial infarction patients. Therefore, we hypothesized that these n-3 fatty acids might prevent potentially fatal ventricular arrhythmias in high-risk patients. Methods and Results—Four hundred two patients with implanted cardioverter\\/defibrillators (ICDs) were randomly

Alexander Leaf; Christine M. Albert; Mark Josephson; David Steinhaus; Jeffrey Kluger; Jing X. Kang; Benjamin Cox; Hui Zhang; David Schoenfeld

2010-01-01

303

The Involvement of Intracellular Calcium in the MCT-Mediated Uptake of Lactic Acid by HeLa Cells  

PubMed Central

The main object of this study is to evaluate the role of intracellular free calcium ion [Ca2+]in in monocarboxylate transporter (MCT) mediated drug uptake by HeLa cells. It was hypothesized that alterations in the [Ca2+]in levels affect Na+-H+ exchanger (NHE) regulated pHin and thereby produce the proton-motivated driving force for monocarboxylate-mediated substrate transport. The changes in intracellular pH (pHin) and MCT-mediated uptake rates of L-lactic acid by HeLa cells, a human cervical adenocarcinoma cell line, were evaluated under the conditions, whose [Ca2+]in concentrations were altered by various calcium modulators, such as EGTA-AM (a chelator), nifedipine (a Ca++ channel antagonist) and A23187 (an ionophore). For comparison purpose, the L-lactic acid uptake by HeLa cells was also evaluated under various pHin conditions induced by dexamethasone. The effects of the extracellular sodium concentration on the L-lactic acid uptake by HeLa cells were evaluated to determine the involvement of NHE-regulated pH changes in the MCT mediated drug uptake process. The [Ca2+]in concentrations and pHin in HeLa were assessed using fluorescent probes fura-2 and 2?,7?-bis[2-carboxyethyl-5-carboxyfluorescein] (BCECF), respectively. The treatment of HeLa cells with A23187 at concentrations of 50 and 100 ?M enhanced [Ca2+]in by 100% and 200% of the control, respectively. EGTA/AM (50 ?M) or nifedipine (100 ?M) did not cause any significant changes in the [Ca2+]in levels, whereas EGTA/AM (100 ?M) and nifedipine (200 ?M) reduced the [Ca2+]in levels by 30% and 25%, respectively, as compared with the control. A23187 at a concentration of 100 ?M in the incubation medium lowered pHin (pH 5) and subsequently the uptake rate of lactic acid by 50% (0.47 ± 0.03 ?mol/mg protein/min) of the control. In contrast, nifedipine (200 ?M) and EGTA-AM (100 ?M), the calcium modulators that lowered the [Ca2+]in levels and maintained the higher pHin (pH>6) of HeLa cells, enhanced the uptake rate of lactic acid by 60% and 130% of the control, respectively. The results of this study demonstrated that there was a close correlation between the [Ca2+]in level and pHin and that NHEs were involved with the MCT mediated uptake process in HeLa cells. An understanding of the role of [Ca2+]in in the MCT mediated transport process could provide an efficient strategy to improve the systemic delivery of monocarboxylate substrates through the cervical mucosa.

Cheeti, Sravanthi; Lee, Chi H.

2009-01-01

304

Mineralisation of reconstituted collagen using polyvinylphosphonic acid/polyacrylic acid templating matrix protein analogues in the presence of calcium, phosphate and hydroxyl ions  

PubMed Central

The complex morphologies of mineralised collagen fibrils are regulated through interactions between the collagen matrix and non-collagenous extracellular proteins. In the present study, polyvinylphosphonic acid, a biomimetic analogue of matrix phosphoproteins, was synthesised and confirmed with FTIR and NMR. Biomimetic mineralisation of reconstituted collagen fibrils devoid of natural non-collagenous proteins was demonstrated with TEM using a Portland cement-containing resin composite and a phosphate-containing fluid in the presence of polyacrylic acid as sequestration, and polyvinylphosphonic acid as templating matrix protein analogues. In the presence of these dual biomimetic analogues in the mineralisation medium, intrafibrillar and extrafibrillar mineralisation via bottom-up nanoparticle assembly based on the nonclassical crystallisation pathway could be identified. Conversely, only large mineral spheres with no preferred association with collagen fibrils were observed in the absence of biomimetic analogues in the medium. Mineral phases were evident within the collagen fibrils as early as 4 hours after the initially-formed amorphous calcium phosphate nanoprecursors were transformed into apatite nanocrystals. Selected area electron diffraction patterns of highly mineralised collagen fibrils were nearly identical to those of natural bone, with apatite crystallites preferentially aligned along the collagen fibril axes.

Kim, Young Kyung; Gu, Li-sha; Bryan, Thomas E.; Kim, Jong Ryul; Chen, Liang; Liu, Yan; Yoon, James C.; Breschi, Lorenzo; Pashley, David H.; Tay, Franklin R.

2010-01-01

305

Serum phospholipid fatty acids and prostate cancer risk: results from the prostate cancer prevention trial.  

PubMed

Inflammation may be involved in prostate cancer development and progression. This study examined the associations between inflammation-related phospholipid fatty acids and the 7-year-period prevalence of prostate cancer in a nested case-control analysis of participants, aged 55-84 years, in the Prostate Cancer Prevention Trial during 1994-2003. Cases (n = 1,658) were frequency matched to controls (n = 1,803) on age, treatment, and prostate cancer family history. Phospholipid fatty acids were extracted from serum, and concentrations of ?-3, ?-6, and trans-fatty acids (TFAs) were expressed as proportions of the total. Logistic regression models estimated odds ratios and 95% confidence intervals of associations of fatty acids with prostate cancer by grade. No fatty acids were associated with low-grade prostate cancer risk. Docosahexaenoic acid was positively associated with high-grade disease (quartile 4 vs. 1: odds ratio (OR) = 2.50, 95% confidence interval (CI): 1.34, 4.65); TFA 18:1 and TFA 18:2 were linearly and inversely associated with risk of high-grade prostate cancer (quartile 4 vs. 1: TFA 18:1, OR = 0.55, 95% CI: 0.30, 0.98; TFA 18:2, OR = 0.48, 95% CI: 0.27, 0.84). The study findings are contrary to those expected from the pro- and antiinflammatory effects of these fatty acids and suggest a greater complexity of effects of these nutrients with regard to prostate cancer risk. PMID:21518693

Brasky, Theodore M; Till, Cathee; White, Emily; Neuhouser, Marian L; Song, Xiaoling; Goodman, Phyllis; Thompson, Ian M; King, Irena B; Albanes, Demetrius; Kristal, Alan R

2011-04-24

306

Calcium influx signals normal flagellar RNA induction following acid shock of Chlamydomonas reinhardtii  

Microsoft Academic Search

Acid shock of Chlamydomonas results in flagellar excision and induction of flagellar protein RNAs. The magnitude of flagellar RNA accumulations after flagellar excision by mechanical shear depends on the extracel]ular Ca2+ concentration. In this report, we demonstrate that the magnitude and duration of flagellar RNA accumulations are signaled by an acid shock-induced Ca2+ influx. RNA accumulations were greater in cells

John H. Evans; Laura R. Keller

1997-01-01

307

Omega-3 fatty acids: their role in the prevention and treatment of atherosclerosis related risk factors and complications.  

PubMed

Fatty acids are an important source of energy which can have an influence on serum lipids. Omega-3 and omega-6 fatty acids, both polyunsaturated fatty acids, have been advocated as replacement for saturated fat. Omega-3 fatty acids, derived from fish and certain green plants, lower serum triglycerides, but they have also been shown to have a direct effect on myocardial contractility, blood pressure, platelet function, coagulation factors, cell-mediated immunity and markers of inflammation. Recently available clinical trial data, including those using the concentrated omega-3 fatty acid preparation Omacor, indicate that omega-3 fatty acids are valuable in preventing sudden death following myocardial infarction. Studies indicate that omega-3 fatty acids are just as effective as, or have a benefit superior to, statins in secondary prevention. Omacor is also useful in the treatment of hypertriglyceridaemia, both as monotherapy and in combination with statins. PMID:12800463

Bhatnagar, D; Durrington, P N

2003-05-01

308

Inhibition of Calcium Oxalate Crystal Growth in vitro by Uropontin: Another Member of the Aspartic Acid-Rich Protein Superfamily  

Microsoft Academic Search

The majority of human urinary stones are primarily composed of calcium salts. Although normal urine is frequently supersaturated with respect to calcium oxalate, most humans do not form stones. Inhibitors are among the multiple factors that may influence the complex process of urinary stone formation. We have isolated an inhibitor of calcium oxalate crystal growth from human urine by monoclonal

H. Shiraga; W. Min; W. J. Vandusen; M. D. Clayman; D. Miner; C. H. Terrell; J. R. Sherbotie; J. W. Foreman; C. Przysiecki; E. G. Neilson; J. R. Hoyer

1992-01-01

309

Omega-3 polyunsaturated fatty acids: a necessity for a comprehensive secondary prevention strategy  

PubMed Central

Long-chain omega-3 polyunsaturated fatty acid (PUFA) supplementation has been used for the secondary prevention of fatal and nonfatal myocardial infarction (MI). However, the benefit of this therapy is frequently confused with other established treatments in the therapeutic strategy among such patients. We review the data on omega-3 PUFA use in secondary care and consider indications for its use which include post-MI and raised triglycerides. We suggest that the available evidence supports the use of omega-3 supplementation as part of the comprehensive secondary care package for post-MI patients.

Patel, Jeetesh V; Tracey, Inessa; Hughes, Elizabeth A; Lip, Gregory YH

2009-01-01

310

Aluminum and acid effects on calcium and phosphorus metabolism in young growing chickens (Gallus gallus domesticus) and mallard ducks (Anas platyrhynchos).  

PubMed

Acidification is associated with increased mortality, reduced growth, and bone abnormalities in birds. Associated with acid deposition is an increase in aluminum availability due to solubilization from soil and other sources. (Conversely, experimental diets containing aluminum sulfate have much reduced pHs.) The present studies compare the effects of two levels of dietary acid (sulfuric acid) (0.122 and 0.56 mol H+ per kg feed; 0.056 and 0.277 mol sulfate per kg feed) and dietary aluminum (aluminum sulfate at 0.1 and 0.5%; sulfate at 0. 056 and 0.277 mol sulfate per kg feed) on bone growth, mineralization, and phosphorous/calcium homeostasis in growing birds (chickens and mallard ducks). Growth was reduced by the high acid (chicken) and aluminum (ducks and chickens) diets. A reduction in bone mineralization was observed in birds receiving aluminum-containing diets [low aluminum diet: decreased tibia ash, calcium, and phosphorus (chickens); high aluminum diet: decreased tibia dry weight, % of ash and mg; ash, calcium (chickens, ducks as % of ash), and phosphorus (chickens mg/duck, % of ash)]. Moreover, plasma concentrations of inorganic phosphate were reduced in chicks on the high aluminum diet. There were also marked decreases in bone growth and mineralization [tibia weight, ash (mg), calcium (mg), phosphorus (mg)] and plasma concentrations of 1,25-dihydroxy vitamin D3 in chicks on the high acid diet compared to those on a control diet. These changes were probably due to reduced feed intake; changes in bone indices being of a greater or similar magnitude in pairfed control. There was little change in bone indices, growth rate or feed consumption in ducklings receiving either the low or high acid diets. It is concluded that aluminum directly adversely affected bone mineralization whereas acid effects are mediated in part by changes in feed consumption. PMID:9601924

Capdevielle, M C; Hart, L E; Goff, J; Scanes, C G

1998-07-01

311

Effects of calcium on seed germination, seedling growth and photosynthesis of six forest tree species under simulated acid rain.  

PubMed

We selected six tree species, Pinus massoniana Lamb., Cryptomeria fortunei Hooibr. ex Otto et Dietr., Cunninghamia lanceolata (Lamb.) Hook., Liquidambar formosana Hance, Pinus armandii Franch. and Castanopsis chinensis Hance, which are widely distributed as dominant species in the forest of southern China where acid deposition is becoming more and more serious in recent years. We investigated the effects and potential interactions between simulated acid rain (SiAR) and three calcium (Ca) levels on seed germination, radicle length, seedling growth, chlorophyll content, photosynthesis and Ca content in leaves of these six species. We found that the six species showed different responses to SiAR and different Ca levels. Pinus armandii and C. chinensis were very tolerant to SiAR, whereas the others were more sensitive. The results of significant SiAR?×?Ca interactions on different physiological parameters of the six species demonstrate that additional Ca had a dramatic rescue effect on the seed germination and seedling growth for the sensitive species under SiAR. Altogether, we conclude that the negative effects of SiAR on seed germination, seedling growth and photosynthesis of the four sensitive species could be ameliorated by Ca addition. In contrast, the physiological processes of the two tolerant species were much less affected by both SiAR and Ca treatments. This conclusion implies that the degree of forest decline caused by long-term acid deposition may be attributed not only to the sensitivity of tree species to acid deposition, but also to the Ca level in the soil. PMID:21470980

Liu, Ting-Wu; Wu, Fei-Hua; Wang, Wen-Hua; Chen, Juan; Li, Zhen-Ji; Dong, Xue-Jun; Patton, Janet; Pei, Zhen-Ming; Zheng, Hai-Lei

2011-04-06

312

Intravenous ascorbic acid to prevent and treat cancer-associated sepsis?  

PubMed Central

The history of ascorbic acid (AA) and cancer has been marked with controversy. Clinical studies evaluating AA in cancer outcome continue to the present day. However, the wealth of data suggesting that AA may be highly beneficial in addressing cancer-associated inflammation, particularly progression to systemic inflammatory response syndrome (SIRS) and multi organ failure (MOF), has been largely overlooked. Patients with advanced cancer are generally deficient in AA. Once these patients develop septic symptoms, a further decrease in ascorbic acid levels occurs. Given the known role of ascorbate in: a) maintaining endothelial and suppression of inflammatory markers; b) protection from sepsis in animal models; and c) direct antineoplastic effects, we propose the use of ascorbate as an adjuvant to existing modalities in the treatment and prevention of cancer-associated sepsis.

2011-01-01

313

Conformational properties of acidic oligo- and disaccharides and their ability to bind calcium: a molecular modeling study.  

PubMed

The conformational analysis of disaccharides composed of two constituents of alginic acid (?-D-mannuronic and ?-L-guluronic acids) was performed. Several additional aspects, such as pH and the type of ionic environment were taken into account. The calculations were performed on the two levels of theory: semi-empirical (PM3) conformational search in vacuo and molecular dynamics with explicit solvent based on the biomolecular (GROMOS) force field. The results indicate that the values of glycosidic dihedral angles can vary in a very similar range, independently of the disaccharide composition. The presence of interresidual hydrogen bonds involving carboxyl groups reduces the ability for calcium ion binding. The type and the concentration of cations in the solution do not practically affect the conformation of disaccharides. Both disaccharides and the oligosaccharides composed of corresponding units exhibit a similar degree of conformational flexibility; only in the case of oligosaccharides containing the ?-l-guluronate units, the glycosidic bonds are much more rigid when compared to those of disaccharides. PMID:22704197

Plazinski, Wojciech

2012-05-26

314

Ursolic acid in cancer prevention and treatment: molecular targets, pharmacokinetics and clinical studies.  

PubMed

Discovery of bioactive molecules and elucidation of their molecular mechanisms open up an enormous opportunity for the development of improved therapy for different inflammatory diseases, including cancer. Triterpenoids isolated several decades ago from various medicinal plants now seem to have a prominent role in the prevention and therapy of a variety of ailments and some have already entered Phase I clinical trials. One such important and highly investigated pentacyclic triterpenoid, ursolic acid has attracted great attention of late for its potential as a chemopreventive and chemotherapeutic agent in various types of cancer. Ursolic acid has been shown to target multiple proinflammatory transcription factors, cell cycle proteins, growth factors, kinases, cytokines, chemokines, adhesion molecules, and inflammatory enzymes. These targets can potentially mediate the chemopreventive and therapeutic effects of ursolic acid by inhibiting the initiation, promotion and metastasis of cancer. This review not only summarizes the diverse molecular targets of ursolic acid, but also provides an insight into the various preclinical and clinical studies that have been performed in the last decade with this promising triterpenoid. PMID:23499879

Shanmugam, Muthu K; Dai, Xiaoyun; Kumar, Alan Prem; Tan, Benny K H; Sethi, Gautam; Bishayee, Anupam

2013-03-13

315

Increased tissue levels of omega-3 polyunsaturated fatty acids prevents pathological preterm birth.  

PubMed

Omega-3 polyunsaturated fatty acids such as eicosapentaenoic acid (EPA) have anti-inflammatory effects. Preterm birth is an important problem in modern obstetrics and one of the main causes is an inflammation. We here showed that abundance of omega-3 fatty acids reduced the incidence of preterm birth induced by LPS with fat-1 mice, capable of converting omega-6 to omega-3 fatty acids. We also indicated that the gene expression of IL-6 and IL-1? in uteruses and the number of cervical infiltrating macrophages were reduced in fat-1 mice. The analyses of lipid metabolomics showed the high level of 18-hydroxyeicosapentaenoate in fat-1 mice, which was derived from EPA and was metabolized to anti-inflammatory product named resolvin E3 (RvE3). We finally showed that the administration of RvE3 to LPS-exposed pregnant wild type mice lowered the incidence of preterm birth. Our data suggest that RvE3 could be a potential new therapeutic for the prevention of preterm birth. PMID:24177907

Yamashita, Aki; Kawana, Kei; Tomio, Kensuke; Taguchi, Ayumi; Isobe, Yosuke; Iwamoto, Ryo; Masuda, Koji; Furuya, Hitomi; Nagamatsu, Takeshi; Nagasaka, Kazunori; Arimoto, Takahide; Oda, Katsutoshi; Wada-Hiraike, Osamu; Yamashita, Takahiro; Taketani, Yuji; Kang, Jing X; Kozuma, Shiro; Arai, Hiroyuki; Arita, Makoto; Osuga, Yutaka; Fujii, Tomoyuki

2013-11-01

316

Preventive effects of ellagic Acid against Doxorubicin-induced cardio-toxicity in mice.  

PubMed

Preventive effects of ellagic acid against doxorubicin-induced cardiac oxidative, inflammatory and apoptotic stress were examined. This agent at 0.25, 0.5 or 1 % was added in feed and supplied to mice for 8 weeks, and followed by doxorubicin treatment. Ellagic acid intake increased its deposit in heart. Pre-intake of this compound at 0.5 and 1 % significantly attenuated doxorubicin caused increase in plasma creatine phosphokinase activity. Doxorubicin treatment decreased glutathione content, increased reactive oxygen species (ROS), malonyldialdehyde (MDA), interleukin (IL)-6, IL-10, monocyte chemoattractant protein-1 and tumor necrosis factor-alpha levels, declined glutathione peroxidase (GPX) and superoxide dismutase (SOD) activities, and enhanced xanthine oxidases (XO) activity in heart. Ellagic acid intake dose-dependently reserved glutathione content, lowered ROS and MDA levels, and reduced XO activity. This compound at 0.5 and 1 % retained GPX and SOD activities, and decreased cytokines in heart. Doxorubicin treatment raised cardiac activity and protein production of caspase-3, nuclear factor kappa B (NF-?B) p50 and p65. Ellagic acid dose-dependently lowered caspase-3 activity and cleaved caspase-3 formation, and at 0.5 and 1 % declined activity and protein level of NF-?B. Doxorubicin treatment also up-regulated cardiac expression of p-p38, p-ERK 1/2 and p-JNK, and ellagic acid at 0.5 and 1 % suppressed p-p38 expression and at 1 % down-regulated p-ERK 1/2 expression. These findings suggest that ellagic acid is a potent cardiac protective agent against doxorubicin. PMID:23322372

Lin, Ming-Cheng; Yin, Mei-Chin

2013-09-01

317

Controlled release of gentamicin from calcium phosphate—poly(lactic acid- co-glycolic acid) composite bone cement  

Microsoft Academic Search

Modification of a self setting bone cement with biodegradable microspheres to achieve controlled local release of antibiotics without compromising mechanical properties was investigated. Different biodegradable microsphere batches were prepared from poly(lactic-co-glycolic acid) (PLGA) using a spray-drying technique to encapsulate gentamicin crobefate varying PLGA composition and drug loading. Microsphere properties such as surface morphology, particle size and antibiotic drug release profiles

Julia Schnieders; Uwe Gbureck; Roger Thull; Thomas Kissel

2006-01-01

318

Crystal size distributions of induced calcium carbonate crystals in polyaspartic acid and Mytilus edulis acidic organic proteins aqueous solutions  

Microsoft Academic Search

Different concentrations of soluble matrix extracts from Mytilus edulis and polyaspartic acid were mixed with CaCl2 aqueous solutions to produce CaCO3 crystallizations under controlled conditions. The obtained crystals were observed at several intervals of time by optical microscopy and scanning electron microscopy (SEM). Image treatment of the SEM images allowed quantifying the crystal size distribution (CSD) in different crystallization conditions.

Josep Roqué; Judit Molera; Màrius Vendrell-Saz; Nativitat Salvadó

2004-01-01

319

Acid-sensing ion channel 1a mediates acid-induced increases in intracellular calcium in rat articular chondrocytes  

Microsoft Academic Search

Acid-sensing ion channels (ASICs) are cationic channels that are activated by extracellular acidification and implicated in\\u000a pain perception, ischemic stroke, mechanosensation, learning, and memory. It has been shown that ASIC1a is an extracellular\\u000a pH sensor in the central and peripheral nervous systems, but its physiological and pathological roles in non-neural cells\\u000a are poorly understood. We demonstrated a novel physiological function

Feng-Lai Yuan; Fei-Hu Chen; Wei-Guo Lu; Xia Li; Fan-Rong Wu; Jian-Ping Li; Cheng-Wan Li; Yu Wang; Teng-Yue Zhang; Wei Hu

2010-01-01

320

Cyclic ADP-ribose and Nicotinic Acid Adenine Dinucleotide Phosphate (NAADP) as Messengers for Calcium Mobilization*  

PubMed Central

Cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate were discovered >2 decades ago. That they are second messengers for mobilizing Ca2+ stores has since been firmly established. Separate stores and distinct Ca2+ channels are targeted, with cyclic ADP-ribose acting on the ryanodine receptors in the endoplasmic reticulum, whereas nicotinic acid adenine dinucleotide phosphate mobilizes the endolysosomes via the two-pore channels. Despite the structural and functional differences, both messengers are synthesized by a ubiquitous enzyme, CD38, whose crystal structure and catalytic mechanism have now been well elucidated. How this novel signaling enzyme is regulated remains largely unknown and is the focus of this minireview.

Lee, Hon Cheung

2012-01-01

321

Calcium Calculator  

MedlinePLUS

... Fun Stuff Fun Stuff Best for Bones Food Calcium Calculator How much calcium do you get every day? Remember, you need ... Deal with Vitamin D List of Foods with Calcium & Vitamin D Calcium Calculator Fooling Around with Food ...

322

Secondary prevention of heart disease – knowledge among cardiologists and ?-3 (Omega3) fatty acid prescribing behaviors in Karachi, Pakistan  

Microsoft Academic Search

BACKGROUND: The use of omega-3 fatty acids is a currently proven strategy for secondary prevention of heart disease. The prescription practices for this important nutraceutical is not currently known. It is imperative to assess the knowledge of cardiologists regarding the benefits of omega-3 fatty acids and to determine the frequency of its prescription. The aim of the study was to

Saqib A Gowani; Sana Shoukat; Ather M Taqui; Hashim M Hanif; Wasiq F Rawasia; Zeeshan Qadri; Sajid H Dhakam

2009-01-01

323

Somatostatin prevents the postoperative increases in plasma amino acid clearance and urea synthesis after elective cholecystectomy.  

PubMed Central

The importance of glucagon on postoperative changes in hepatic amino-nitrogen conversion were investigated in six patients undergoing elective cholecystectomy for uncomplicated gall stones. Patients were given infusions of somatostatin (bolus of 6 micrograms/kg followed by continuous infusion of 6 micrograms/kg/h) from induction of anaesthesia to the end of investigation, the first postoperative day (30 hours). Controls were 16 patients undergoing the same procedures omitting the somatostatin infusion. In all patients blood concentration and plasma clearance of total alpha-amino-nitrogen, and amino acid stimulated rate of urea synthesis were measured. Elective cholecystectomy decreased blood alpha-amino-nitrogen concentration from mean (SEM) 2.9 (0.2) to 2.4 (0.1) mmol/l (p < 0.05), increased the clearance of total alpha-amino-nitrogen from 5.2 (0.3) to 6.6 (0.3) ml/s (p < 0.05), and increased the rate of amino acid stimulated urea synthesis from 27 (1) to 37 (2) mumol/s (p < 0.05) pointing to increased hepatic removal of amino-nitrogen at expense of plasma amino-nitrogen. Infusion of somatostatin prevented increase of glucagon for 24 hours after surgery, and prevented the negative changes in postoperative nitrogen homeostasis resulting from the postoperative changes in hepatic nitrogen conversion, suggesting glucagon as mediator. The exact mechanism remains in doubt, however, because of the multiple effects of somatostatin.

Heindorff, H; Billesb?lle, P; Pedersen, S L; Hansen, R; Vilstrup, H

1995-01-01

324

Effects of calcium hydroxide and calcium chloride addition to bentonite in iron ore pelletization.  

PubMed

Pyrite ash is created as waste from the roasting of pyrite ores during the production of sulphuric acid. These processes generate great amounts of pyrite ash waste that is generally land filled. This creates serious environmental pollution due to the release of acids and toxic substances. Pyrite ash waste can be utilized in the iron production industry as a blast furnace feed to process this waste and prevent environmental pollution. The essential parameters affecting the pelletization process of pyrite ash were studied using bentonite as a binder. Experiments were then carried out using bentonite and a mixture of bentonite with calcium hydroxide and calcium chloride in order to make the bentonite more effective. The metallurgical properties of pyrite ash, bentonite, calcium hydroxide, calcium chloride, a mixture of these and sintered pellets were studied using X-ray analysis. The crushing strength tests were carried out to investigate the strength of pyrite ash waste pellets. The results of these analyses showed that pyrite ash can be agglomerated to pellets and used in the iron production industry as a blast furnace feed. The crushing strength of the pellets containing calcium hydroxide and calcium chloride in addition to bentonite was better than the strength of pellets prepared using only bentonite binder. PMID:17121116

Tugrul, Nurcan; Derun, Emek Moroydor; Pi?kin, Mehmet

2006-10-01

325

Steel Industry Slags Compared with Calcium Carbonate in Neutralizing Acid Mine Soil1  

Microsoft Academic Search

Ohio has substantial lands impacted by surface mining for coal and an active steel industry. Steel industry slags have been used as liming compounds for agriculture and acid mine soil reclamation. This 3-year study evaluates slags from Ohio steel mills in greenhouse trials where these materials are compared to reagent grade CaCO3 in their ability to improve plant growth on

DAVID A. MUNN

326

Effect of Calcium Salts of Long-Chain Fatty Acids on Dairy Cows in Early Lactation  

Microsoft Academic Search

Twenty dairy cows in early lactation were assigned to one of two dietary treat- ment groups based on milk production and days in milk. Treatments were a total mixed ration containing 13.2% whole cottonseed on a DM basis with or without added Ca salts of long-chain fatty acids. Treatments were fed ad libitum for 11 wk. Dry matter intake and

B. A. Kent; M. J. Arambel

1988-01-01

327

Ryanodine receptors contribute to bile acid-induced pathological calcium signaling and pancreatitis in mice  

PubMed Central

Biliary pancreatitis is the most common etiology for acute pancreatitis, yet its pathophysiological mechanism remains unclear. Ca2+ signals generated within the pancreatic acinar cell initiate the early phase of pancreatitis, and bile acids can elicit anomalous acinar cell intracellular Ca2+ release. We previously demonstrated that Ca2+ released via the intracellular Ca2+ channel, the ryanodine receptor (RyR), contributes to the aberrant Ca2+ signal. In this study, we examined whether RyR inhibition protects against pathological Ca2+ signals, acinar cell injury, and pancreatitis from bile acid exposure. The bile acid tauro-lithocholic acid-3-sulfate (TLCS) induced intracellular Ca2+ oscillations at 50 ?M and a peak-plateau signal at 500 ?M, and only the latter induced acinar cell injury, as determined by lactate dehydrogenase (LDH) leakage. Pretreatment with the RyR inhibitors dantrolene or ryanodine converted the peak-plateau signal to a mostly oscillatory pattern (P < 0.05). They also reduced acinar cell LDH leakage, basolateral blebbing, and propidium iodide uptake (P < 0.05). In vivo, a single dose of dantrolene (5 mg/kg), given either 1 h before or 2 h after intraductal TLCS infusion, reduced the severity of pancreatitis down to the level of the control (P < 0.05). These results suggest that the severity of biliary pancreatitis may be ameliorated by the clinical use of RyR inhibitors.

Orabi, Abrahim I.; Muili, Kamaldeen A.; Luo, Yuhuan; Sarwar, Sheharyar; Mahmood, Syeda Maham; Wang, Dong; Choo-Wing, Rayman; Singh, Vijay P.; Parness, Jerome; Ananthanaravanan, Meena; Bhandari, Vineet; Perides, George

2012-01-01

328

An evaluation of waste gypsum-based precipitated calcium carbonate for acid mine drainage neutralization.  

PubMed

Precipitated CaCO(3) compounds recovered from pulped waste gypsum using some carbonate and hydroxide-based reagents were evaluated for their utilization in acid mine drainage (AMD) neutralization. The neutralization potentials, acid neutralization capacities and compositions of the CaCO(3) compounds were determined and compared with some commercial CaCO(3). It was observed that CaCO(3) recovered from waste gypsum using Na(2)CO(3) significantly neutralized AMD compared with commercial CaCO(3) and that recovered using both (NH(4))(2)CO(3) or NH(4)OH-CO(2) reagents. Moreover, a higher acid neutralization capacity of 1,370 kg H(2)SO(4)/t was determined for CaCO(3) recovered from waste gypsum using Na(2)CO(3) compared with an average of 721 and 1,081 kg H(2)SO(4)/t for ammonium-based CaCO(3) and commercial CaCO(3) respectively. The inorganic carbon content for the CaCO(3) recovered using Na(2)CO(3) and ammonium-based reagents of 49 and 34% respectively confirmed their observed neutralization potentials and acid neutralization capacities, while energy dispersive X-ray fluorescence suggested absence of major oxide impurities, with the exception of residual SO(4)(2-) and Na(2)O which still requires further reduction in the respective compounds. PMID:22508119

Zvimba, J N; Mulopo, J; Bologo, L T; Mathye, M

2012-01-01

329

Calcium dependent release of gamma-aminobutyric acid (GABA) from human cerebral cortex.  

PubMed

The release of the amino acids GABA, taurine, glycine, glutamine and leucine from human neocortex was investigated in vitro by utilizing brain tissue removed during 8 standard temporal lobectomies for epilepsy or tumor. Slices (0.5 mm thick) were cut from each biopsy and randomly placed in three different chambers. After 90 min preincubation, the three sets of slices were incubated for 60 s in wells containing, respectively, (A) regular ACSF (control), (B) ACSF with 50 mM K+ (to depolarize the cell membrane) and (C) ACSF with 50 mM K+, 0 mM Ca2+ and 4 mM Mg2+ (depolarization during blocked synaptic transmission). The content of amino acids in the wells was determined by high-performance liquid chromatography after pre-column derivatization of the amino acids with o-phthalaldehyde. Membrane depolarization (well B) increased the GABA release to 650% (620 pmol/mg) of control (well A, 95 pmol/mg). Blocking synaptic transmission (well C) reduced the evoked release by 50% (360 pmol/mg). The release of glycine, taurine, glutamine and leucine during membrane depolarization was not significantly different from the control values. The data provide evidence for a Ca(2+)-dependent release of GABA, supporting a possible role of this amino acid as a neurotransmitter in human neocortex. PMID:1508401

Haugstad, T S; Hegstad, E; Langmoen, I A

1992-07-01

330

A Comparison of Calcium Gluconate and Zephiran for the Treatment of Dermal Hydrofluoric Acid Exposure  

Microsoft Academic Search

Hydrofluoric acid (HF), an aqueous form of hydrogen fluoride (Lewis 1993), typically emits a colorless irritating gas at room temperature (Hance, Solomon, Salmon, Fall, & Cass 1997). This highly corrosive, commonly used inorganic compound readily attacks materials such as concrete, glass, natural rubber, and metal alloys containing silica (EPA Chemical Profile 1987). The Occupational Safety and Health Administration (OSHA) has

Joshua G. Alters

331

ALUMINUM SOLUBILITY, CALCIUM-ALUMINUM EXCHANGE, AND PH IN ACID FOREST SOILS  

EPA Science Inventory

Important components in several models designed to describe the effects of acid deposition on soils and surface waters are the pH-A1 and Ca-A1 exchange relationships. f A1 solubility is controlled by A1 trihydroxide minerals, the theoretical pH-A1 relationship can be described by...

332

Bioefficacy of a novel calcium–potassium salt of (?)-hydroxycitric acid  

Microsoft Academic Search

Obesity is associated with cardiovascular disease, diabetes and certain forms of cancer. Popular strategies on weight loss often fail to address many key factors such as fat mass, muscle density, bone density, water mass, their inter-relationships and impact on energy production, body composition, and overall health and well-being. (?)-Hydroxycitric acid (HCA), a natural plant extract from the dried fruit rind

Bernard W. Downs; Manashi Bagchi; Gottumukkala V. Subbaraju; Michael A. Shara; Harry G. Preuss; Debasis Bagchi

2005-01-01

333

Safety assessment of (?)-hydroxycitric acid and Super CitriMax ®, a novel calcium\\/potassium salt  

Microsoft Academic Search

(?)-Hydroxycitric acid (HCA) is a principle constituent (10–30%) of the dried fruit rind of Garcinia cambogia, a plant native to Southeastern Asia. The dried rind has been used for centuries throughout Southeast Asia as a food preservative, flavoring agent and carminative. Extensive experimental studies show that HCA inhibits fat synthesis and reduces food intake. The objective of this review is

M. G. Soni; G. A. Burdock; H. G. Preuss; S. J. Stohs; S. E. Ohia; D. Bagchi

2004-01-01

334

Reducing cannabinoid abuse and preventing relapse by enhancing endogenous brain levels of kynurenic acid.  

PubMed

In the reward circuitry of the brain, ?-7-nicotinic acetylcholine receptors (?7nAChRs) modulate effects of ?(9)-tetrahydrocannabinol (THC), marijuana's main psychoactive ingredient. Kynurenic acid (KYNA) is an endogenous negative allosteric modulator of ?7nAChRs. Here we report that the kynurenine 3-monooxygenase (KMO) inhibitor Ro 61-8048 increases brain KYNA levels and attenuates cannabinoid-induced increases in extracellular dopamine in reward-related brain areas. In the self-administration model of drug abuse, Ro 61-8048 reduced the rewarding effects of THC and the synthetic cannabinoid WIN 55,212-2 in squirrel monkeys and rats, respectively, and it also prevented relapse to drug-seeking induced by reexposure to cannabinoids or cannabinoid-associated cues. The effects of enhancing endogenous KYNA levels with Ro 61-8048 were prevented by positive allosteric modulators of ?7nAChRs. Despite a clear need, there are no medications approved for treatment of marijuana dependence. Modulation of KYNA offers a pharmacological strategy for achieving abstinence from marijuana and preventing relapse. PMID:24121737

Justinova, Zuzana; Mascia, Paola; Wu, Hui-Qiu; Secci, Maria E; Redhi, Godfrey H; Panlilio, Leigh V; Scherma, Maria; Barnes, Chanel; Parashos, Alexandra; Zara, Tamara; Fratta, Walter; Solinas, Marcello; Pistis, Marco; Bergman, Jack; Kangas, Brian D; Ferré, Sergi; Tanda, Gianluigi; Schwarcz, Robert; Goldberg, Steven R

2013-10-13

335

Mitochondrial Complex II Prevents Hypoxic but Not Calcium- and Proapoptotic Bcl-2 Protein-induced Mitochondrial Membrane Potential Loss*  

PubMed Central

Mitochondrial membrane potential loss has severe bioenergetic consequences and contributes to many human diseases including myocardial infarction, stroke, cancer, and neurodegeneration. However, despite its prominence and importance in cellular energy production, the basic mechanism whereby the mitochondrial membrane potential is established remains unclear. Our studies elucidate that complex II-driven electron flow is the primary means by which the mitochondrial membrane is polarized under hypoxic conditions and that lack of the complex II substrate succinate resulted in reversible membrane potential loss that could be restored rapidly by succinate supplementation. Inhibition of mitochondrial complex I and F0F1-ATP synthase induced mitochondrial depolarization that was independent of the mitochondrial permeability transition pore, Bcl-2 (B-cell lymphoma 2) family proteins, or high amplitude swelling and could not be reversed by succinate. Importantly, succinate metabolism under hypoxic conditions restores membrane potential and ATP levels. Furthermore, a reliance on complex II-mediated electron flow allows cells from mitochondrial disease patients devoid of a functional complex I to maintain a mitochondrial membrane potential that conveys both a mitochondrial structure and the ability to sequester agonist-induced calcium similar to that of normal cells. This finding is important as it sets the stage for complex II functional preservation as an attractive therapy to maintain mitochondrial function during hypoxia.

Hawkins, Brian J.; Levin, Mark D.; Doonan, Patrick J.; Petrenko, Nataliya B.; Davis, Christiana W.; Patel, Vickas V.; Madesh, Muniswamy

2010-01-01

336

Efficacy of casein phosphopeptide-amorphous calcium phosphate to prevent stain absorption on freshly bleached enamel: An in vitro study  

PubMed Central

Background: Teeth when subjected to bleaching bring about the desiccation of the enamel, making it more susceptible to stain absorption. While subjecting the freshly bleached enamel surface to various surface treatments of Fluoride and Casein Phosphopeptide - Amorphous Calcium phosphate (CPP-ACP) brought about the reduction in stain absorption, which is assessed in this study. Aims: The study aims to evaluate the tea stain absorption on freshly bleached enamel surface of extracted human teeth with varied surface treatment. The stain absorption was evaluated at the end of one hour and 24 hours post bleaching. Materials and Methods: Forty extracted human permanent maxillary central incisors were subjected to bleaching with 10% carbamide peroxide for eight days. They were divided into four groups of 10 each. Group I was control group. Group II was immersed in tea solution without surface treatment, while Group III and IV were immersed in tea solution with surface treatment of topical Fluoride and CPP-ACP respectively. Spectrophotometer was used for color analysis. Results: Surface treatment with CPP-ACP and topical fluoride on freshly beached enamel surface, significantly reduced the stain absorption. Conclusion: Remineralizing agents reduce stain absorption after tooth bleaching.

Singh, Raghuwar D; Ram, Sabita M; Shetty, Omkar; Chand, Pooran; Yadav, Rakesh

2010-01-01

337

An oxidized metabolite of linoleic acid increases intracellular calcium in rat adrenal glomerulosa cells.  

PubMed

EKODE, an epoxy-keto derivative of linoleic acid, was previously shown to stimulate aldosterone secretion in rat adrenal glomerulosa cells. In the present study, we investigated the effect of exogenous EKODE on cytosolic [Ca(2+)] increase and aimed to elucidate the mechanism involved in this process. Through the use of the fluorescent Ca(2+)-sensitive dye Fluo-4, EKODE was shown to rapidly increase intracellular [Ca(2+)] ([Ca(2+)](i)) along a bell-shaped dose-response relationship with a maximum peak at 5 microM. Experiments performed in the presence or absence of Ca(2+) revealed that this increase in [Ca(2+)](i) originated exclusively from intracellular pools. EKODE-induced [Ca(2+)](i) increase was blunted by prior application of angiotensin II, Xestospongin C, and cyclopiazonic acid, indicating that inositol trisphosphate (InsP(3))-sensitive Ca(2+) stores can be mobilized by EKODE despite the absence of InsP(3) production. Accordingly, EKODE response was not sensitive to the phospholipase C inhibitor U-73122. EKODE mobilized a Ca(2+) store included in the thapsigargin (TG)-sensitive stores, although the interaction between EKODE and TG appears complex, since EKODE added at the plateau response of TG induced a rapid drop in [Ca(2+)](i). 9-oxo-octadecadienoic acid, another oxidized derivative of linoleic acid, also increases [Ca(2+)](i), with a dose-response curve similar to EKODE. However, arachidonic and linoleic acids at 10 microM failed to increase [Ca(2+)](i) but did reduce the amplitude of the response to EKODE. It is concluded that EKODE mobilizes Ca(2+) from an InsP(3)-sensitive store and that this [Ca(2+)](i) increase is responsible for aldosterone secretion by glomerulosa cells. Similar bell-shaped dose-response curves for aldosterone and [Ca(2+)](i) increases reinforce this hypothesis. PMID:16822961

Payet, Marcel D; Goodfriend, Theodore L; Bilodeau, Lyne; Mackendale, Cherilu; Chouinard, Lucie; Gallo-Payet, Nicole

2006-07-05

338

Soil calcium status and the response of stream chemistry to changing acidic deposition rates  

USGS Publications Warehouse

Despite a decreasing trend in acidic deposition rates over the past two to three decades, acidified surface waters in the northeastern United States have shown minimal changes. Depletion of soil Ca pools has been suggested as a cause, although changes in soil Ca pools have not been directly related to long-term records of stream chemistry. To investigate this problem, a comprehensive watershed study was conducted in the Neversink River Basin, in the Catskill Mountains of New York, during 1991-1996. Spatial variations of atmospheric deposition, soil chemistry, and stream chemistry were evaluated over an elevation range of 817-1234 m to determine whether these factors exhibited elevational patterns. An increase in atmospheric deposition of SO4 with increasing elevation corresponded with upslope decreases of exchangeable soil base concentrations and acid-neutralizing capacity of stream water. Exchangeable base concentrations in homogeneous soil incubated within the soil profile for one year also decreased with increasing elevation. An elevational gradient in precipitation was not observed, and effects of a temperature gradient on soil properties were not detected. Laboratory leaching experiments with soils from this watershed showed that (1) concentrations of Ca in leachate increased as the concentrations of acid anions in added solution increased, and (2) the slope of this relationship was positively correlated with base saturation. Field and laboratory soil analyses are consistent with the interpretation that decreasing trends in acid-neutralizing capacity in stream water in the Neversink Basin, dating back to 1984, are the result of decreases in soil base saturation caused by acidic deposition.

Lawrence, G. B.; David, M. B.; Lovett, G. M.; Murdoch, P. S.; Burns, D. A.; Stoddard, J. L.; Baldigo, B. P.; Porter, J. H.; Thompson, A. W.

1999-01-01

339

Hyperuricosuric calcium nephrolithiasis.  

PubMed

Since the findings of Yü and Gutman [1], the hyperuricosuric calcium stone former is a unique clinical entity. While an impressive number of clinical and epidemiologic studies implicate hyperuricosuria in calcium stone formation, the exact physicochemical mechanism by which uric acid affects calcium oxalate crystallization has not been proven. Allopurinol decreases stone recurrences and is the drug of choice for patients with isolated HCN. PMID:12474638

Sorensen, Carsten M; Chandhoke, Paramjit S

2002-12-01

340

Studies of Cardiac Muscle with a High Permeability to Calcium Produced by Treatment with Ethylenediaminetetraacetic Acid  

PubMed Central

Thin strips of frog ventricle were isolated and bathed for 15 min in a solution containing 140 mM KCl, 5 mM Na2ATP, 3 mM EDTA, and 10 mM Tris buffer at pH 7.0. The muscle was then exposed to contracture solutions containing 140 mM KCl, 5 mM Na2ATP, 1 mM MgCl2, 10 mM Tris, 3 mM EGTA, and CaCl2 in amounts to produce concentrations of free calcium from 10-4.8 M to 10-9 M. The muscles developed some tension at approximately 10-8 M, and maximum tension was achieved in 10-5 M Ca++. They relaxed in Ca++ concentrations less than 10-8 M. The development of tension by the EDTA-treated muscles was normalized by comparison with twitch tension at a stimulation rate of 9 per min before exposure to EDTA. In 10-5 M Ca++ tension was always several times the twitch tension and was greater than the contracture tension of a frog ventricular strip in KCl low Na-Ringer. Tension equal to half-maximum was produced at approximately 10-6.2 M Ca++. Intracellular recording of membrane potential indicated that after EDTA treatment the resting potential of cells in Ringer solution with 10-5 M Ca or less was between 5 and 20 mv. Contracture solutions did not produce tension without prior treatment with EDTA. The high permeability of the membrane produced by EDTA was reversed and the normal resting and action potentials restored in 1 mM Ca-Ringer. Similar studies of EDTA-treated rabbit right ventricular papillary muscle produced a similar tension vs. Ca++ concentration relation, and the high permeability state reversed with exposure to normal Krebs solution.

Winegard, Saul

1971-01-01

341

Benidipine, a dihydropyridine-calcium channel blocker, prevents lysophosphatidylcholine-induced injury and reactive oxygen species production in human aortic endothelial cells.  

PubMed

Lysophosphatidylcholine (lysoPC) is a component of oxidized low-density lipoproteins (oxLDLs), which play an important role in the pathogenesis of atherosclerosis. In this study, we examined whether benidipine hydrochloride (benidipine), a dihydropyridine-calcium channel blocker with antioxidant activity, prevents lysoPC (C 16:0)-induced injury of human aortic endothelial cells (HAEC). Treatment of HAECs with lysoPC changed cell morphology, decreased cell viability and induced DNA fragmentation, leading to apoptosis. Additionally, lysoPC species containing palmitoyl (C 16:0) or stearoyl (C 18:0), which are the major components of oxLDLs, stimulated reactive oxygen species (ROS) production and induced caspase-3/7-like activity in HAECs, but lysoPC species with short acyl chains did not affect either ROS production or caspase-3/7-like activity. Pretreatment with benidipine (0.3-3 micromol/L) for 24 h protected against lysoPC-induced cytotoxicity in the endothelial cells and the drug inhibited both lysoPC-stimulated ROS production and caspase-3/7-like activation with a similar potency. Since caspase-3/7 is involved in executing the apoptotic process, the reduction of the activity of this enzyme by benedipine may explain the anti-apoptotic effect of the drug. However, benidipine did not suppress lysoPC-induced phosphorylation of mitogen-activated protein kinases and Ca2+ influx in HAECs. These results suggest that the anti-oxidant properties of benidipine may be responsible for its ability to inhibit ROS production, resulting in reduced activation of caspase-3/7. In conclusion, benidipine suppresses lysoPC-induced endothelial dysfunction through inhibition of ROS production, which is due at least in part to its antioxidant effect, and not through the inhibition of L-type voltage-dependent calcium channels. PMID:15585201

Matsubara, Masahiro; Hasegawa, Kazuhide

2005-01-01

342

Two calcium mobilizing pathways implicated within abscisic acid-induced stomatal closing in Arabidopsis thaliana  

Microsoft Academic Search

The present study investigated whether, depending on the abscisic acid (ABA) concentration, phospholipase C (PLC) would be\\u000a implicated within a Ca2+ mobilizing pathway that would regulate stomatal aperture under standard watering conditions. Among Al sensitive mutants the\\u000a als1-1 mutant of Arabidopsis thaliana (L.) Heynh. (Columbia-4 ecotype) was selected for a pharmacological approach of stomatal closing in leaf epidermal peels\\u000a induced

A. Cousson

2007-01-01

343

Aluminum solubility, calcium-aluminum exchange, and pH in acid forest soils  

Microsoft Academic Search

The pH-Al and Ca-Al exchange relationships are important components in several models designed to describe the effects of acid deposition on soils and surface waters. If Al solubility is controlled by Al trihydroxide minerals, the theoretical pH-Al relationship can be described by log(al{sup 3+}) = logK - 3pH. However, in practice it is often better described by log(Al{sup 3+}) =

J. O. Reuss; R. W. E. Hopper; P. M. Walthall; E. C. Roswall

2009-01-01

344

Action of niflumic acid on evoked and spontaneous calcium-activated chloride and potassium currents in smooth muscle cells from rabbit portal vein.  

PubMed Central

1. The action of niflumic acid was studied on spontaneous and evoked calcium-activated chloride (ICl(Ca)) and potassium (IK(Ca)) currents in rabbit isolated portal vein cells. 2. With the nystatin perforated patch technique in potassium-containing solutions at a holding potential of -77 mV (the potassium equilibrium potential), niflumic acid produced a concentration-dependent inhibition of spontaneous transient inward current (STIC, calcium-activated chloride current) amplitude. The concentration to reduce the STIC amplitude by 50% (IC50) was 3.6 x 10(-6) M. 3. At -77 mV holding potential, niflumic acid converted the STIC decay from a single exponential to 2 exponential components. In niflumic acid the fast component of decay was faster, and the slow component was slower than the control decay time constant. Increasing the concentration of niflumic acid enhanced the decay rate of the fast component and reduced the decay rate of the slow component. 4. The effect of niflumic acid on STIC amplitude was voltage-dependent and at -50 and +50 mV the IC50 values were 2.3 x 10(-6) M and 1.1 x 10(-6) M respectively (cf. 3.6 x 10(-6) M at -77 mV). 5. In K-free solutions at potentials of -50 mV and +50 mV, niflumic acid did not induce a dual exponential STIC decay but just increased the decay time constant at both potentials in a concentration-dependent manner. 6. Niflumic acid, in concentrations up to 5 x 10(-5) M, had no effect on spontaneous calcium-activated potassium currents.(ABSTRACT TRUNCATED AT 250 WORDS)

Hogg, R. C.; Wang, Q.; Large, W. A.

1994-01-01

345

Omega-3 fatty acid oxidation products prevent vascular endothelial cell activation by coplanar polychlorinated biphenyls  

SciTech Connect

Coplanar polychlorinated biphenyls (PCBs) may facilitate development of atherosclerosis by stimulating pro-inflammatory pathways in the vascular endothelium. Nutrition, including fish oil-derived long-chain omega-3 fatty acids, such as docosahexaenoic acid (DHA, 22:6{omega}-3), can reduce inflammation and thus the risk of atherosclerosis. We tested the hypothesis that cyclopentenone metabolites produced by oxidation of DHA can protect against PCB-induced endothelial cell dysfunction. Oxidized DHA (oxDHA) was prepared by incubation of the fatty acid with the free radical generator 2,2-azo-bis(2-amidinopropane) dihydrochloride (AAPH). Cellular pretreatment with oxDHA prevented production of superoxide induced by PCB77, and subsequent activation of nuclear factor-{kappa}B (NF-{kappa}B). A{sub 4}/J{sub 4}-neuroprostanes (NPs) were identified and quantitated using HPLC ESI tandem mass spectrometry. Levels of these NPs were markedly increased after DHA oxidation with AAPH. The protective actions of oxDHA were reversed by treatment with sodium borohydride (NaBH{sub 4}), which concurrently abrogated A{sub 4}/J{sub 4}-NP formation. Up-regulation of monocyte chemoattractant protein-1 (MCP-1) by PCB77 was markedly reduced by oxDHA, but not by un-oxidized DHA. These protective effects were proportional to the abundance of A{sub 4}/J{sub 4} NPs in the oxidized DHA sample. Treatment of cells with oxidized eicosapentaenoic acid (EPA, 20:5{omega}-3) also reduced MCP-1 expression, but less than oxDHA. Treatment with DHA-derived cyclopentenones also increased DNA binding of NF-E2-related factor-2 (Nrf2) and downstream expression of NAD(P)H:quinone oxidoreductase (NQO1), similarly to the Nrf-2 activator sulforaphane. Furthermore, sulforaphane prevented PCB77-induced MCP-1 expression, suggesting that activation of Nrf-2 mediates the observed protection against PCB77 toxicity. Our data implicate A{sub 4}/J{sub 4}-NPs as mediators of omega-3 fatty acid-mediated protection against the endothelial toxicity of coplanar PCBs.

Majkova, Zuzana [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536-0200 (United States); Layne, Joseph [Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40536-0200 (United States); Sunkara, Manjula; Morris, Andrew J. [Division of Cardiovascular Medicine, The Gill Heart Institute, University of Kentucky, Lexington, KY 40536-0509 (United States); Toborek, Michal [Department of Neurosurgery, University of Kentucky, Lexington, KY 40536-0200 (United States); Hennig, Bernhard, E-mail: bhennig@email.uky.edu [Graduate Center for Toxicology, University of Kentucky, Lexington, KY 40536-0200 (United States); Graduate Center for Nutritional Sciences, University of Kentucky, Lexington, KY 40536-0200 (United States); Department of Animal and Food Sciences, University of Kentucky, Lexington, KY 40536-0200 (United States)

2011-02-15

346

Omega-3 fatty acid oxidation products prevent vascular endothelial cell activation by coplanar polychlorinated biphenyls  

PubMed Central

Coplanar polychlorinated biphenyls (PCBs) may facilitate development of atherosclerosis by stimulating pro-inflammatory pathways in the vascular endothelium. Nutrition, including fish oil-derived long-chain omega-3 fatty acids, such as docosahexaenoic acid (DHA, 22:6?-3), can reduce inflammation and thus the risk of atherosclerosis. We tested the hypothesis that cyclopentenone metabolites produced by oxidation of DHA can protect against PCB-induced endothelial cell dysfunction. Oxidized DHA (oxDHA) was prepared by incubation of the fatty acid with the free radical generator 2,2-azo-bis(2-amidinopropane) dihydrochloride (AAPH). Cellular pretreatment with oxDHA prevented production of superoxide induced by PCB77, and subsequent activation of nuclear factor-?B (NF-?B). A4/J4-neuroprostanes (NPs) were identified and quantitated using HPLC ESI tandem mass spectrometry. Levels of these NPs were markedly increased after DHA oxidation with AAPH.. The protective actions of oxDHA were reversed by treatment with sodium borohydride (NaBH4), which concurrently abrogated A4/J4-NP formation. Up-regulation of monocyte chemoattractant protein-1 (MCP-1)by PCB77 was markedly reduced by oxDHA, but not by un-oxidized DHA. These protective effects were proportional to the abundance of A4/J4NPs in the oxidized DHA sample. Treatment of cells with oxidized eicosapentaenoic acid (EPA, 20:5?-3) also reduced MCP-1 expression, but less than oxDHA. Treatment with DHA-derived cyclopentenones also increased DNA binding of NF-E2-related factor-2 (Nrf2)and downstream expression of NAD(P)H:quinone oxidoreductase (NQO1), similarly to the Nrf-2 activator sulforaphane. Furthermore, sulforaphane prevented PCB77-induced MCP-1 expression, suggesting that activation of Nrf-2 mediates the observed protection against PCB77 toxicity. Our data implicate A4/J4-NPs as mediators of omega-3 fatty acid-mediated protection against the endothelial toxicity of coplanar PCBs.

Majkova, Zuzana; Layne, Joseph; Sunkara, Manjula; Morris, Andrew J.; Toborek, Michal; Hennig, Bernhard

2011-01-01

347

SR 140333 prevents potentiation by citric acid of plasma exudation induced by histamine in airways.  

PubMed

We here report a model of potentiation by citric acid of airway microvascular leakage induced by histamine and its modification by the tachykinin NK1 and NK2 receptor antagonists, SR 140333 ((S)1-{2-[3-(3,4-dichlorophenyl)-1-(3-iso-propoxyphenylacetyl)p iperidin- 3-yl]ethyl}-phenyl-1-azoniabicyclo[2.2.2]octane, chloride) and SR 48968 (S)-N-methyl-N-[4-(4-acetyl-amino-4-phenylpiperidino)-2-(3,4- dichlorophenyl-butyl]benzamide. Guinea-pigs exposed to an acrosol of citric acid 0.4 M for 1 h developed 24 h later a hyperresponsiveness to histamine-induced microvascular leakage measured by Evans blue dye extravasation. SR 140333, but not SR 48968 (1 mg kg-1 given each once 30 min before citric acid exposure), prevented this potentiation. These results provide further evidence of the role of tachykinin and tachykinin NK1 receptor stimulation on airway hyperresponsiveness and its neurogenic inflammatory component. PMID:8858307

Biyah, K; Molimard, M; Emonds-Alt, X; Advenier, C

1996-07-25

348

Complex cardiac defects after ethanol exposure during discrete cardiogenic events in zebrafish: Prevention with folic acid.  

PubMed

Background: Fetal alcohol spectrum disorder (FASD) describes a range of birth defects including various congenital heart defects (CHDs). Mechanisms of FASD-associated CHDs are not understood. Whether alcohol interferes with a single critical event or with multiple events in heart formation is not known. Results: Our zebrafish embryo experiments showed that ethanol interrupts different cardiac regulatory networks and perturbs multiple steps of cardiogenesis (specification, myocardial migration, looping, chamber morphogenesis, and endocardial cushion formation). Ethanol exposure during gastrulation until cardiac specification or during myocardial midline migration did not produce severe or persistent heart development defects. However, exposure comprising gastrulation until myocardial precursor midline fusion or during heart patterning stages produced aberrant heart looping and defective endocardial cushions. Continuous exposure during entire cardiogenesis produced complex cardiac defects leading to severely defective myocardium, endocardium, and endocardial cushions. Supplementation of retinoic acid with ethanol partially rescued early heart developmental defects, but the endocardial cushions did not form correctly. In contrast, supplementation of folic acid rescued normal heart development, including the endocardial cushions. Conclusions: Our results indicate that ethanol exposure interrupted divergent cardiac morphogenetic events causing heart defects. Folic acid supplementation was effective in preventing a wide spectrum of ethanol-induced heart developmental defects. Developmental Dynamics 242:1184-1201, 2013. © 2013 Wiley Periodicals, Inc. PMID:23832875

Sarmah, Swapnalee; Marrs, James A

2013-09-02

349

alpha-Tocopherol and ascorbic acid prevent memory deficits provoked by chronic hyperprolinemia in rats.  

PubMed

In the present study we investigated the action of alpha-tocopherol and ascorbic acid on the effects elicited by chronic hyperprolinemia on rat performance in the Morris water maze. Rats received subcutaneous injections of proline (experimental group) twice a day, with 10 h-interval, from the 6 to 28th days of age or an equivalent volume of 0.9% saline solution (controls). Half of the proline-treated group also received intraperitoneal administration of alpha-tocopherol (40 mg/kg) and of ascorbic acid (100 mg/kg) from the 6 to 28th days of life. On the 60th day of life, rats were subjected to testing in the water maze. Results show that chronic proline administration provokes impairment on spatial learning in reference memory task, as revealed by the increase of latency in acquisition, in the probe trial and in crossing over the platform location, as well as by the number of crossings, when compared to saline-treated animals. Proline-treated rats also demonstrated a reduced efficiency to find the platform position in the working memory task. Rats chronically treated with proline plus alpha-tocopherol and ascorbic acid had above effects prevented, suggesting the participation of oxidative stress in such effects. Our findings lend support to a novel therapeutic strategy, based on these vitamins, to the cognitive dysfunction associated with hyperprolinemia type II. PMID:16214240

Delwing, Daniela; Bavaresco, Caren S; Monteiro, Siomara C; Matté, Cristiane; Netto, Carlos Alexandre; Wyse, Angela T S

2005-10-06

350

Nucleic Acid polymers prevent the establishment of duck hepatitis B virus infection in vivo.  

PubMed

Nucleic acid polymers (NAPs) are novel, broad-spectrum antiviral compounds that use the sequence-independent properties of phosphorothioate oligonucleotides (PS-ONs) as amphipathic polymers to block amphipathic interactions involved in viral entry. Using the duck hepatitis B virus (DHBV) model of human hepatitis B virus infection, NAPs have been shown to have both entry and postentry antiviral activity against DHBV infection in vitro in primary duck hepatocytes (PDH). In the current study, various NAPs were assessed for their prophylactic activity in vivo against DHBV infection in ducks. The degenerate NAP REP 2006 prevented the development of widespread and persistent DHBV infection in 14-day-old ducks, while the acidic-pH-sensitive NAP REP 2031 had little or no prophylactic effect. REP 2006 displayed significant toxicity in ducks, which was attributed to CpG-mediated proinflammation, while REP 2031 (which has no CpG motifs) displayed no toxicity. A third NAP, REP 2055, which was designed to retain amphipathic activity at acidic pH and contained no CpG motifs, was well tolerated and displayed prophylactic activity against DHBV infection at doses as low as 1 mg/kg of body weight/day. These studies suggest that NAPs can be easily and predictably tailored to retain anti-DHBV activity and to have minimal toxic effects in vivo. Future studies are planned to establish the therapeutic efficacy of NAPs against persistent DHBV infection. PMID:23939904

Noordeen, Faseeha; Vaillant, Andrew; Jilbert, Allison R

2013-08-12

351

Microwave-assisted synthesis of biocompatible europium-doped calcium hydroxyapatite and fluoroapatite luminescent nanospindles functionalized with poly(acrylic acid).  

PubMed

Europium-doped calcium hydroxyapatite and fluoroapatite nanophosphors functionalized with poly(acrylic acid) (PAA) have been synthesized through a one-pot microwave-assisted hydrothermal method from aqueous basic solutions containing calcium nitrate, sodium phosphate monobasic, and PAA, as well as sodium fluoride in the case of the fluoroapatite particles. In both cases a spindlelike morphology was obtained, resulting from an aggregation process of smaller subunits which also gave rise to high specific surface area. The size of the nanospindles was 191 (32) × 40 (5) nm for calcium hydroxyapatite and 152 (24) × 38 (6) nm for calcium fluoroapatite. The luminescent nanoparticles showed the typical red luminescence of Eu(3+), which was more efficient for the fluoroapatite particles than for the hydroxyapatite. This is attributed to the presence of OH(-) quenchers in the latter. The nanophosphors showed negligible toxicity for Vero cells. Both PAA-functionalized nanophosphors showed a very high (up to at least 1 week) colloidal stability in 2-(N-morpholino)ethanesulfonic acid (MES) at pH 6.5, which is a commonly used buffer for physiological pH. All these features make both kinds of apatite-based nanoparticles promising tools for biomedical applications, such as luminescent biolabels and tracking devices in drug delivery systems. PMID:23317411

Escudero, Alberto; Calvo, Mauricio E; Rivera-Fernández, Sara; de la Fuente, Jesús M; Ocaña, Manuel

2013-01-29

352

Calcium Oscillations  

PubMed Central

Calcium signaling results from a complex interplay between activation and inactivation of intracellular and extracellular calcium permeable channels. This complexity is obvious from the pattern of calcium signals observed with modest, physiological concentrations of calcium-mobilizing agonists, which typically present as sequential regenerative discharges of stored calcium, a process referred to as calcium oscillations. In this review, we discuss recent advances in understanding the underlying mechanism of calcium oscillations through the power of mathematical modeling. We also summarize recent findings on the role of calcium entry through store-operated channels in sustaining calcium oscillations and in the mechanism by which calcium oscillations couple to downstream effectors.

Dupont, Genevieve; Combettes, Laurent; Bird, Gary S.; Putney, James W.

2011-01-01

353

21 CFR 184.1185 - Calcium acetate.  

Code of Federal Regulations, 2013 CFR

...also known as acetate of lime or vinegar salts, is the calcium salt of acetic acid. It may be produced by the calcium hydroxide neutralization of acetic acid. (b) The ingredient meets the specifications of the Food Chemicals...

2013-04-01

354

Calcium mobilization by nicotinic acid adenine dinucleotide phosphate (NAADP) in rat astrocytes.  

PubMed

Nicotinic acid adenine dinucleotide phosphate (NAADP) has been shown to release intracellular Ca(2+) in several types of cells. We have used Ca(2+)-sensitive fluorescent dyes (Fura-2, Fluo-4) to measure intracellular Ca(2+) in astrocytes in culture and in situ. Bath-applied NAADP elicited a reversible and concentration-dependent Ca(2+) rise in up to 90% of astrocytes in culture (EC(50)=7 microM). The NAADP-evoked Ca(2+) rise was maintained in the absence of extracellular Ca(2+), but was suppressed after depleting the Ca(2+) stores of the ER with ATP (20 microM), with cyclopiazonic acid (10 microM) or with ionomycin (5 microM). P(2) receptor antagonist pyridoxalphosphate-6-azophenyl-2'4'-disulfonic acid (PPADS, 100 microM), IP(3) receptor blocker 2-aminoethoxydiphenyl borate (2-APB, 100 microM) and PLC inhibitor U73122 (10 microM) also reduced or suppressed the NAADP-evoked Ca(2+) rise. NAADP still evoked a Ca(2+) response after application of glycyl-l-phenylalanine-beta-naphthylamide (GPN, 200 microM), which permeabilizes lysosomes, or preincubation with H(+)-ATPase inhibitor bafilomycin A1 (4 microM) and of p-trifluoromethoxy carbonyl cyanide phenylhydrazone (FCCP, 2 microM), that impairs mitochondrial Ca(2+) handling. In acute brain slices, NAADP (10 microM) evoked Ca(2+) transients in cerebellar Bergmann glial cells and in hippocampal astrocytes. Our results suggest that NAADP recruits Ca(2+) from inositol 1,4,5-trisphosphate-sensitive Ca(2+) stores in mammalian astrocytes, at least partly by activating metabotropic P(2)Y receptors. PMID:16289677

Singaravelu, Karthika; Deitmer, Joachim W

2005-11-14

355

Cyclic nucleotide phosphodiesterase inhibitors prevent aggregation of human platelets by raising cyclic AMP and reducing cytoplasmic free calcium mobilization.  

PubMed

Cyclic nucleotide phosphodiesterase inhibitors (HL-725, RO 15-2041, cilostamide, quercetin and MY-5445) potently inhibit human platelet aggregation induced by ADP. In parallel, PDE inhibitors inhibit the increase in cytoplasmic free Ca2+ evoked by ADP, as measured with the fluorescent probe quin 2. The inhibition of ADP-induced aggregation and rise in [Ca2+]i is potentiated by PGE1 which stimulates adenylate cyclase and is inhibited by adrenaline which inhibits adenylate cyclase. PDE inhibitors increase human platelet cAMP levels in the presence of low concentrations of PGE1. It is suggested that PDE inhibitors prevent platelet aggregation by raising cAMP levels and by subsequent inhibition of cytoplasmic free Ca2+ mobilization. PMID:3035738

Lanza, F; Beretz, A; Stierlé, A; Corre, G; Cazenave, J P

1987-03-01

356

Calcium-Dependent Protein Phosphorylation May Mediate the Gibberellic Acid Response in Barley Aleurone1  

PubMed Central

Peptide substrates of well-defined protein kinases were microinjected into aleurone protoplasts of barley (Hordeum vulgare L. cv Himalaya) to inhibit, and therefore identify, protein kinase-regulated events in the transduction of the gibberellin (GA) and abscisic acid signals. Syntide-2, a substrate designed for Ca2+- and calmodulin (CaM)-dependent kinases, selectively inhibited the GA response, leaving constitutive and abscisic acid-regulated events unaffected. Microinjection of syntide did not affect the GA-induced increase in cytosolic [Ca2+], suggesting that it inhibited GA action downstream of the Ca2+ signal. When photoaffinity-labeled syntide-2 was electroporated into protoplasts and cross-linked to interacting proteins in situ, it selectively labeled proteins of approximately 30 and 55 kD. A 54-kD, soluble syntide-2 phosphorylating protein kinase was detected in aleurone cells. This kinase was activated by Ca2+ and was CaM independent, but was inhibited by the CaM antagonist N-(6-aminohexyl)-5-chloro-1-naphthalene-sulfonamide (250 ?m), suggesting that it was a CaM-domain protein kinase-like activity. These results suggest that syntide-2 inhibits the GA response of the aleurone via an interaction with this kinase, implicating the 54-kD kinase as a Ca2+-dependent regulator of the GA response in these cells.

Ritchie, Sian; Gilroy, Simon

1998-01-01

357

Stimulated Efflux of Amino Acids and Glutathione from Cultured Hippocampal Slices by Omission of Extracellular Calcium  

PubMed Central

Omission of extracellular Ca2+ for 15 min from the incubation medium of cultured hippocampal slices stimulated the efflux of glutathione, phosphoethanolamine, hypotaurine, and taurine. The efflux was reduced by several blockers of gap junctions, i.e. carbenoxolone, flufenamic acid, and endothelin-1, and by the connexin43 hemichannel blocking peptide Gap26 but was unchanged by the P2X7 receptor inhibitor oxidized ATP, a pannexin1 hemichannel blocking peptide and an inactive analogue of carbenoxolone. Pretreatment of the slices with the neurotoxin N-methyl-d -aspartate left the efflux by Ca2+ omission unchanged, indicating that the stimulated efflux primarily originated from glia. Elevated glutamate efflux was detected when Ca2+ omission was combined with the glutamate uptake blocker l-trans-pyrrolidine-2,4-dicarboxylate and when both Ca2+ and Mg2+ were omitted from the medium. Omission of Ca2+ for 15 min alone did not induce delayed toxicity, but in combination with blocked glutamate uptake, significant cell death was observed 24 h later. Our results indicate that omission of extracellular Ca2+ stimulates efflux of glutathione and specific amino acids including glutamate via opening of glial hemichannels. This type of efflux may have protective functions via glutathione efflux but can aggravate toxicity in situations when glutamate reuptake is impaired, such as following a stroke.

Stridh, Malin H.; Tranberg, Mattias; Weber, Stephen G.; Blomstrand, Fredrik; Sandberg, Mats

2008-01-01

358

Calcium phenylphosphonate as a host for 4-aminobenzoic acid-Synthesis, characterization, and cation adsorption from ethanol solution  

SciTech Connect

Crystalline lamellar calcium phenylphosphonate retained 4-aminobenzoic acid inside its cavity without leaching. The intense infrared bands in the 1160-695 cm{sup -1} interval confirmed the presence of the phosphonate groups attached to the inorganic layer, with sharp and intense peaks in X-ray diffraction patterns, which gave basal distances of 1532 and 1751 pm for the original and the intercalated compounds, respectively. The thermogravimetric curves of both layered compounds showed the release of water molecules and the organic moiety in distinct stages, to yield a final Ca(PO{sub 3}){sub 2} residue. Solid-state {sup 31}P nuclear magnetic resonance spectra presented only one peak for the phenylphosphonate groups attached to the main inorganic polymeric structure near 12.4 ppm. The adsorption isotherms from ethanol gave the maximum adsorption capacities of 1.68 and 0.50 mmol g{sup -1} for copper and cobalt, respectively, whose average stability constants followed Co > Cu; the number of ligands was determined as four for both cations.

Lazarin, Angelica M., E-mail: amlazarin2@uem.br [Departamento de Quimica, Universidade Estadual de Maringa, Av. Colombo, 5790, 87020-900 Maringa, PR (Brazil); Ganzerli, Thiago A.; Sernaglia, Rosana L.; Andreotti, Elza I.S. [Departamento de Quimica, Universidade Estadual de Maringa, Av. Colombo, 5790, 87020-900 Maringa, PR (Brazil); Airoldi, Claudio [Institute of Chemistry, University of Campinas, UNICAMP, P.O. Box 6154, 13084-971 Campinas, SP (Brazil)

2009-11-15

359

Computational modelling of the mechanical environment of osteogenesis within a polylactic acid-calcium phosphate glass scaffold.  

PubMed

A computational model based on finite element method (FEM) and computational fluid dynamics (CFD) is developed to analyse the mechanical stimuli in a composite scaffold made of polylactic acid (PLA) matrix with calcium phosphate glass (Glass) particles. Different bioreactor loading conditions were simulated within the scaffold. In vitro perfusion conditions were reproduced in the model. Dynamic compression was also reproduced in an uncoupled fluid-structure scheme: deformation level was studied analyzing the mechanical response of scaffold alone under static compression while strain rate was studied considering the fluid flow induced by compression through fixed scaffold. Results of the model show that during perfusion test an inlet velocity of 25 microm/s generates on scaffold surface a fluid flow shear stress which may stimulate osteogenesis. Dynamic compression of 5% applied on the PLA-Glass scaffold with a strain rate of 0.005 s(-1) has the benefit to generate mechanical stimuli based on both solid shear strain and fluid flow shear stress on large scaffold surface area. Values of perfusion inlet velocity or compression strain rate one order of magnitude lower may promote cell proliferation while values one order of magnitude higher may be detrimental for cells. FEM-CFD scaffold models may help to determine loading conditions promoting bone formation and to interpret experimental results from a mechanical point of view. PMID:19477510

Milan, Jean-Louis; Planell, Josep A; Lacroix, Damien

2009-05-28

360

Lysophosphatidic Acid Increases the Electrophysiological Instability of Adult Rabbit Ventricular Myocardium by Augmenting L-Type Calcium Current  

PubMed Central

Lysophosphatidic acid (LPA) has diverse actions on the cardiovascular system and is widely reported to modulate multiple ion currents in some cell types. However, little is known about its electrophysiological effects on cardiac myocytes. This study investigated whether LPA has electrophysiological effects on isolated rabbit myocardial preparations. The results indicate that LPA prolongs action potential duration at 90% repolarization (APD90) in a concentration- and frequency-dependent manner in isolated rabbit ventricular myocytes. The application of extracellular LPA significantly increases the coefficient of APD90 variability. LPA increased L-type calcium current (ICa,L) density without altering its activation or deactivation properties. In contrast, LPA has no effect on two other ventricular repolarizing currents, the transient outward potassium current (Ito) and the delayed rectifier potassium current (IK). In arterially perfused rabbit left ventricular wedge preparations, the monophasic action potential duration, QT interval, and Tpeak-end are prolonged by LPA. LPA treatment also significantly increases the incidence of ventricular tachycardia induced by S1S2 stimulation. Notably, the effects of LPA on action potentials and ICa,L are PTX-sensitive, suggesting LPA action requires a Gi-type G protein. In conclusion, LPA prolongs APD and increases electrophysiological instability in isolated rabbit myocardial preparations by increasing ICa,L in a Gi protein-dependent manner.

Wei, Yong; Zhao, Li-qun; Qi, Bao-zhen; Xiao, Xing; He, Li; Zhou, Gen-qing; Chen, Song-wen; Li, Hong-li; Ruan, Lei; Zhang, Cun-tai; Liu, Shao-wen

2012-01-01

361

Zoledronic acid prevents loss of trabecular bone after focal irradiation in mice.  

PubMed

Radiation therapy for soft tissue sarcomas and metastatic disease can adversely affect bone, leading to late-onset fragility fractures. Adjunct administration of bisphosphonates has been postulated as means of minimizing these adverse effects. Using a murine model of focal hindlimb irradiation, we examined the potential for zoledronic acid treatment to minimize the deleterious effects of localized radiotherapy (RTx) on bone. Mice received a single, unilateral hindlimb exposure of 20 Gy. Beginning 4 days prior to irradiation, and at 1, 2 and 3 weeks post-irradiation, animals were treated with zoledronic acid or saline/vehicle injections. Areal bone mineral density was assessed at 4 days, and 2, 4 and 12 weeks post-irradiation by dual-energy X-ray absorptiometry (DXA). Micro-computed tomography and axial compression testing were used to quantify changes in morphological and mechanical properties of femurs at 4 and 12 weeks post-irradiation. Radiation had differential effects on cortical and trabecular bone, increasing cortical bone mineral content (BMC), cortical bone volume (BV) and trabecular separation (Tb.Sp) while decreasing trabecular number (Tb.N) by 12 weeks after localized radiotherapy. Administration of zoledronic acid increased hindlimb areal bone mineral density in both the presence and absence of radiotherapy, increased cortical bone mineral content and bone volume, increased trabecular bone volume (BV/TV), increased trabecular number, increased trabecular thickness (Tb.Th), and decreased trabecular separation compared to irradiated and vehicle control femurs. Despite these improvements in morphology with zoledronic acid, no biomechanical advantage was observed. Further work is needed to define the role of bisphosphonates in prevention of post-irradiation fragility fractures. PMID:23772924

Keenawinna, Lihini; Oest, Megan E; Mann, Kenneth A; Spadaro, Joseph; Damron, Timothy A

2013-06-17

362

An acidic peptide sequence of nucleolin-related protein can mediate the attachment of calcium oxalate to renal tubule cells.  

PubMed

Crystals that form in tubular fluid must be retained in the kidney to become stones. Nucleolin-related protein (NRP) is found on the surface of inner medullary collecting duct (IMCD) cells in culture (cIMCD) and selectively adsorbs to calcium oxalate (CaOx). We proposed that NRP mediates attachment to the renal tubular epithelium of Ca stone crystals through an electrostatic interaction with a highly acidic region (acidic fragment [AF]) similar to those of other proteins that have been reported to affect urinary crystal formation. The current studies demonstrate that nucleolin is expressed on both apical and basolateral cell surfaces of cIMCD, reaching a peak in the late stages of mitosis and gradually declining to undetectable levels with maturation of the polarized epithelium. Scraping areas of mature monolayers stimulated the cells surrounding the defects to migrate and proliferate so as to repair them, and these areas demonstrate surface NRP expression and enhanced attachment of CaOx monohydrate crystals. Surface expression of the NRP AF was produced by cloning the NRP AF into a display vector. Transfected cIMCD demonstrating copious surface expression of AF enhanced CaOx attachment 6.7-fold compared with control cIMCD, whereas cells transfected with a vector without the AF did not differ from control. AF was also cloned into a replication-deficient adenovirus and expressed in 293 cells, resulting in AF secretion into the nutrient medium. This medium inhibited CaOx attachment to cIMCD, compared with conditioned medium from cells infected with wild-type virus. These results demonstrate that surface-bound AF can mediate CaOx attachment and that secreted AF can inhibit attachment. These results support the notion that surface-associated NRP could mediate attachment of CaOx to the renal tubule epithelium, thereby causing retention of crystals that might eventually become kidney stones. PMID:15284292

Sorokina, Elena A; Wesson, Jeffrey A; Kleinman, Jack G

2004-08-01

363

Calcium-dependent protein kinases, CDPK4 and CDPK5, affect early steps of jasmonic acid biosynthesis in Nicotiana attenuata  

PubMed Central

Calcium-dependent protein kinases (CDPKs) modulate plant development and growth and are important regulators of biotic and abiotic stress responses. Recently it was found that simultaneously silencing Nicotiana attenuata NaCDPK4 and NaCDPK5 (IRcdpk4/5 plants) results in accumulation of exceptionally high JA levels after wounding or simulated herbivory treatments, which in turn induced high levels of defense metabolites that slowed the growth of Manduca sexta, a specialist insect herbivore. To investigate the mechanism by which NaCDPK4 and NaCDPK5 regulate JA accumulation, we analyzed the transcript levels of all important enzymes involved in JA biosynthesis, but these genes showed no differences between wild-type and IRcdpk4/5 plants. Moreover, the dynamics of JA were similar between these plants, excluding the possibility of decreased degradation rates in IRcdpk4/5 plants. To gain insight into the mechanism by which NaCDPK4 and NaCDPK5 regulate JA biosynthesis, free fatty acids, including C18:3, and (9S,13S)-12-oxo-phytodienoic acid (OPDA), two important precursors of JA were quantified at different times before and after wounding and simulated herbivore feeding treatments. We show that after these treatments, IRcdpk4/5 plants have decreased levels of C18:3, but have enhanced OPDA and JA levels, suggesting that NaCDPK4 and NaCDPK5 have a role in the early steps of JA biosynthesis. The possible role of NaCDPK4 and NaCDPK5 regulating AOS and AOC enzymatic activity is discussed.

Hettenhausen, Christian; Yang, Da-Hai; Baldwin, Ian T.; Wu, Jianqiang

2013-01-01

364

EE-drospirenone-levomefolate calcium versus EE-drospirenone + folic acid: folate status during 24 weeks of treatment and over 20 weeks following treatment cessation  

PubMed Central

Background Adequate folate supplementation in the periconceptional phase is recommended to reduce the risk of neural tube defects. Oral contraceptives may provide a reasonable delivery vehicle for folate supplementation before conception in women of childbearing potential. This study aimed to demonstrate that a fixed-dose combination of an oral contraceptive and levomefolate calcium leads to sustainable improvements in folate status compared with an oral contraceptive + folic acid. Methods This was a double-blind, randomized, parallel-group study in which 172 healthy women aged 18–40 years received ethinylestradiol (EE)-drospirenone-levomefolate calcium or EE-drospirenone + folic acid for 24 weeks (invasion phase), and EE-drospirenone for an additional 20 weeks (folate elimination phase). The main objective of the invasion phase was to examine the area under the folate concentration time-curve for plasma and red blood cell (RBC) folate, while the main objective of the elimination phase was to determine the duration of time for which RBC folate concentration remained ? 906 nmol/L after cessation of EE-drospirenone-levomefolate calcium. Results Mean concentration-time curves for plasma folate, RBC folate, and homocysteine were comparable between treatment groups during both study phases. During the invasion phase, plasma and RBC folate concentrations increased and approached steady-state after about 8 weeks (plasma) or 24 weeks (RBC). After cessation of treatment with levomefolate calcium, folate concentrations decreased slowly. The median time to RBC folate concentrations falling below 906 nmol/L was 10 weeks (95% confidence interval 8–12 weeks) after cessation of EE-drospirenone-levomefolate calcium treatment. Plasma and RBC folate levels remained above baseline values in 41.3% and 89.3% of women, respectively, at the end of the 20-week elimination phase. Conclusion Improvements in folate status were comparable between EE-drospirenone-levomefolate calcium and EE-drospirenone + folic acid. Plasma and RBC folate levels remained elevated for several months following cessation of treatment with EE-drospirenone-levomefolate calcium.

Diefenbach, Konstanze; Trummer, Dietmar; Ebert, Frank; Lissy, Michael; Koch, Manuela; Rohde, Beate; Blode, Hartmut

2013-01-01

365

Enhancing effect of dietary vinegar on the intestinal absorption of calcium in ovariectomized rats.  

PubMed

We studied the effect of dietary vinegar on calcium absorption by using ovariectomized rats fed on a low-calcium diet. The apparent absorption of calcium was higher when the rats were fed on a diet containing 1.6% vinegar for 32 days than when fed on a diet without vinegar (P < 0.05). The calcium content in the femur of the rats given diets containing 0.4% and 1.6% vinegar were also higher (P < 0.05). The serum parathyroid hormone level was lower and the crypt depth of the duodenum thicker in the rats fed on a diet containing 1.6% vinegar (P < 0.05). These results suggest that dietary vinegar enhanced intestinal calcium absorption by improving calcium solubility and by the trophic effect of the acetic acid contained in vinegar, which would reduce the bone turnover caused by ovariectomy and be helpful in preventing osteoporosis. PMID:10380633

Kishi, M; Fukaya, M; Tsukamoto, Y; Nagasawa, T; Takehana, K; Nishizawa, N

1999-05-01

366

The influence of the acidic component of the gas-foaming porogen used in preparing an injectable porous calcium phosphate cement on its properties: acetic acid versus citric acid.  

PubMed

In the present study, macroporous calcium phosphate cements (CPCs) were prepared using a porogen; that is, the gas-foaming technique. The objective was to investigate the influence of the acidic component of the porogen (acetic acid versus citric acid) on several properties of a specified CPC. In all of the cements prepared, the basic component of the porogen was the same, namely, NaHCO(3), and it was added to the powder phase of the cement, while the acidic component of the porogen was dissolved in the liquid phase of the cement. The cements were characterized in terms of initial setting time, porosity, crystallinity, injectability and compressive strength. Also, XRD, FTIR, and SEM techniques were employed to evaluate the phase composition, the chemical groups and the morphological aspects of the porous cements during setting. It was found that the presence of a porogen in a CPC led to significant decreases in both its initial setting time and compressive strength. A CPC made using acetic acid contained a larger amount of the apatite phase but was significantly less injectable and less porous than when citric acid was used. PMID:18161816

Hesaraki, Saeed; Zamanian, Ali; Moztarzadeh, Fatollah

2008-07-01

367

Inhibitory effect of insulin on vasopressin-induced intracellular calcium response is blunted in hyperinsulinemic hypertensive patients: role of membrane fatty acid composition  

Microsoft Academic Search

Impaired insulin-mediated vasodilation has been implicated in hypertension that is associated with the metabolic syndrome.\\u000a The aim of this study was to determine whether an abnormality in membrane fatty acid composition was related to a weakening\\u000a of insulin's inhibitory effect on agonist-stimulated intracellular free calcium elevation. Mild to moderate hypertensive patients\\u000a (n = 27) and normotensive controls (n = 11)

Koichi Maekawa; Takeshi Tsujino; Komei Saito; Jong Il Kim; Yoshihiro Ikeda; Noriaki Emoto; Mitsuhiro Yokoyama

2006-01-01

368

Effect of microbial phytase, vitamin D 3, and citric acid on growth performance and phosphorus, nitrogen and calcium digestibility in growing swine  

Microsoft Academic Search

Two experiments were conducted to determine the effects of feeding microbial phytase, vitamin D3 and\\/or citric acid on grower pig performance and nutrient digestibility. In experiment 1, 30 crossbred pigs (23.4kg) were fed one of five diets during a four week trial. The basal diet (negative control) was based on corn and soybean meal and contained 6.9gkg?1 calcium, 551 IU

Defa Li; Xiangrong Che; Yuqiong Wang; Cao Hong; P. A Thacker

1998-01-01

369

Improved Arndt-Eistert synthesis of alpha-diazoketones requiring minimal diazomethane in the presence of calcium oxide as acid scavenger.  

PubMed

A practical methodology to obtain alpha-diazoketones through an improved Arndt-Eistert synthesis is described. The method allows the efficient transformation of acid halides using a stoichiometric amount of diazomethane in the presence of calcium oxide, without concomitant ketene or haloketone formation. The obtained alpha'-brominated-alpha-diazoketones were employed as suitable substrates for the synthesis of interesting alpha-arylamino-alpha'-halomethylketones. PMID:20672806

Pace, Vittorio; Verniest, Guido; Sinisterra, Josep-Vicent; Alcántara, Andrés R; De Kimpe, Norbert

2010-08-20

370

Localization of Alpha Type II Calcium Calmodulin-Dependent Protein Kinase at Glutamatergic but not gamma -Aminobutyric Acid (GABAergic) Synapses in Thalamus and Cerebral Cortex  

Microsoft Academic Search

The alpha subunit of type II calcium \\/ calmodulin-dependent protein kinase (CAM II kinase-alpha ) plays an important role in longterm synaptic plasticity. We applied preembedding immunocytochemistry (for CAM II kinase-alpha ) and postembedding immunogold labeling [for glutamate or gamma -aminobutyric acid (GABA)] to explore the subcellular relationships between transmitter-defined axon terminals and the kinase at excitatory and inhibitory synapses

Xiao-Bo Liu; Edward G. Jones

1996-01-01

371

Calcium sulfate or coal combustion by-product spread on the soil surface to reduce evaporation, mitigate subsoil acidity and improve plant growth  

Microsoft Academic Search

Removal of sulfur dioxide from flue gas produced by coal-burning power plants has increased the availability of by-products that may be useful as soil amendments for agriculture. We studied the effects of surface layers (caps) of fluidized bed combustion residue-fly ash mixture (FBCR-FA) or calcium sulfate on reduction of evaporative water losses and improvements in subsurface acid soil chemical characteristics.

K. D. Ritchey; R. F. Korcak; C. M. Feldhake; V. C. Baligar; R. B. Clark

1996-01-01

372

Acid Resistance of Enamel Subsurface Lesions Remineralized by a Sugar-Free Chewing Gum Containing Casein Phosphopeptide-Amorphous Calcium Phosphate  

Microsoft Academic Search

The aim of this clinical study was to investigate the acid resistance of enamel lesions remineralized in situ by a sugar-free chewing gum containing casein phosphopeptide-amorphous calcium phosphate nanocomplexes (CPP-ACP: Recaldent™). The study utilized a double-blind, randomized, crossover design with two treatments: (i) sugar-free gum containing 18.8 mg of CPP-ACP, and (ii) sugar-free gum not containing CPP-ACP as control. Subjects

Y. Iijima; F. Cai; P. Shen; G. Walker; C. Reynolds; E. C. Reynolds

2004-01-01

373

Effects of palm oil and calcium soaps of palm oil fatty acids in fattening diets on digestibility, performance and chemical body composition of lambs  

Microsoft Academic Search

The effects on digestibility, performance and chemical body composition of inclusion of palm oil (PO, VETALGRAS®) or calcium soaps of palm oil fatty acids (CaF, MAGNAPAC®), at two levels, in diets of growing lambs were determined. Experimental diets consisted of barley straw and one of five concentrate supplements: control (C, no fat added), low level of PO (LPO, 25gPO\\/kg), low

T. Manso; T. Castro; A. R. Mantecón; V. Jimeno

2006-01-01

374

The effects of acid treatment and calcium ions on the solubility of concanavalin A  

NASA Astrophysics Data System (ADS)

The solubilities for concanavalin A from jack bean meal were determined by the sitting drop and micro-column techniques. Solubilities varied with both the measurement technique and protein preparation procedures. Freshly purified and crystallized concanavalin A showed a normal solubility behavior, except for a slight retrograde region at lower temperatures (? 20°C) and ammonium sulfate concentrations. A salting in effect was also observed at the lower ammonium sulfate concentrations. Treatment with 1.0M acetic acid followed by recalcification lowered the solubility compared to the freshly purified protein as measured with the micro-column technique. Overall, solubilities determined by the sitting drop technique were much higher than those measured with the micro-column method, even for the same protein material and conditions. Further, the results show that protein solubilities must be determined with regard to both the bound and free concentrations of all cofactors.

Cacioppo, Elizabeth; Pusey, Marc Lee

1992-08-01

375

Inhibition of polar calcium movement and gravitropism in roots treated with auxin-transport inhibitors.  

PubMed

Primary roots of maize (Zea mays L.) and pea (Pisum sativum L.) exhibit strong positive gravitropism. In both species, gravistimulation induces polar movement of calcium across the root tip from the upper side to the lower side. Roots of onion (Allium cepa L.) are not responsive to gravity and gravistimulation induces little or no polar movement of calcium across the root tip. Treatment of maize or pea roots with inhibitors of auxin transport (morphactin, naphthylphthalamic acid, 2,3,5-triiodobenzoic acid) prevents both gravitropism and gravity-induced polar movement of calcium across the root tip. The results indicate that calcium movement and auxin movement are closely linked in roots and that gravity-induced redistribution of calcium across the root cap may play an important role in the development of gravitropic curvature. PMID:11540830

Lee, J S; Mulkey, T J; Evans, M L

1984-01-01

376

Acid-sensitive channel inhibition prevents fetal alcohol spectrum disorders cerebellar Purkinje cell loss  

NSDL National Science Digital Library

Ethanol is now considered the most common human teratogen. Educational campaigns have not reduced the incidence of ethanol-mediated teratogenesis, leading to a growing interest in the development of therapeutic prevention or mitigation strategies. On the basis of the observation that maternal ethanol consumption reduces maternal and fetal pH, we hypothesized that a pH-sensitive pathway involving the TWIK-related acid-sensitive potassium channels (TASKs) is implicated in ethanol-induced injury to the fetal cerebellum, one of the most sensitive targets of prenatal ethanol exposure. Pregnant ewes were intravenously infused with ethanol (258 ñ 10 mg/dl peak blood ethanol concentration) or saline in a "3 days/wk binge" pattern throughout the third trimester. Quantitative stereological analysis demonstrated that ethanol resulted in a 45% reduction in the total number of fetal cerebellar Purkinje cells, the cell type most sensitive to developmental ethanol exposure. Extracellular pH manipulation to create the same degree and pattern of pH fall caused by ethanol (manipulations large enough to inhibit TASK 1 channels), resulted in a 24% decrease in Purkinje cell number. We determined immunohistochemically that TASK 1 channels are expressed in Purkinje cells and that the TASK 3 isoform is expressed in granule cells of the ovine fetal cerebellum. Pharmacological blockade of both TASK 1 and TASK 3 channels simultaneous with ethanol effectively prevented any reduction in fetal cerebellar Purkinje cell number. These results demonstrate for the first time functional significance of fetal cerebellar two-pore domain pH-sensitive channels and establishes them as a potential therapeutic target for prevention of ethanol teratogenesis.

Jay Ramadoss (University of Wisconsin); Emilie R Lunde (College of Veterinary Medicine and Biomedical Sciences Veterinary Physiology and Pharmacology); Nengtai Ouyang (Texas A&M College of Veterinary Medicine and Biomedical Sciences Veterinary Physiology and Pharmacology); Wei-Jung A Chen (Texas A&M HSC Neuroscience and Experimental Therapeutics); Dr. Timothy A. Cudd (Texas A&M University Dept. of Veterinary Physiology and Pharmacology)

2008-05-22

377

Acid-sensitive channel inhibition prevents fetal alcohol spectrum disorders cerebellar Purkinje cell loss  

PubMed Central

Ethanol is now considered the most common human teratogen. Educational campaigns have not reduced the incidence of ethanol-mediated teratogenesis, leading to a growing interest in the development of therapeutic prevention or mitigation strategies. On the basis of the observation that maternal ethanol consumption reduces maternal and fetal pH, we hypothesized that a pH-sensitive pathway involving the TWIK-related acid-sensitive potassium channels (TASKs) is implicated in ethanol-induced injury to the fetal cerebellum, one of the most sensitive targets of prenatal ethanol exposure. Pregnant ewes were intravenously infused with ethanol (258 ± 10 mg/dl peak blood ethanol concentration) or saline in a “3 days/wk binge” pattern throughout the third trimester. Quantitative stereological analysis demonstrated that ethanol resulted in a 45% reduction in the total number of fetal cerebellar Purkinje cells, the cell type most sensitive to developmental ethanol exposure. Extracellular pH manipulation to create the same degree and pattern of pH fall caused by ethanol (manipulations large enough to inhibit TASK 1 channels), resulted in a 24% decrease in Purkinje cell number. We determined immunohistochemically that TASK 1 channels are expressed in Purkinje cells and that the TASK 3 isoform is expressed in granule cells of the ovine fetal cerebellum. Pharmacological blockade of both TASK 1 and TASK 3 channels simultaneous with ethanol effectively prevented any reduction in fetal cerebellar Purkinje cell number. These results demonstrate for the first time functional significance of fetal cerebellar two-pore domain pH-sensitive channels and establishes them as a potential therapeutic target for prevention of ethanol teratogenesis.

Ramadoss, Jayanth; Lunde, Emilie R.; Ouyang, Nengtai; Chen, Wei-Jung A.; Cudd, Timothy A.

2008-01-01

378

Inhibition of Stabilin-2 elevates circulating hyaluronic acid levels and prevents tumor metastasis  

PubMed Central

Hyaluronic acid (HA) has been implicated in the proliferation and metastasis of tumor cells. However, most previous studies were conducted on extracellular matrix or pericellular HA, and the role of circulating HA in vivo has not been studied. HA is rapidly cleared from the bloodstream. The scavenger receptor Stabilin-2 (Stab2) is considered a major clearance receptor for HA. Here we report a dramatic elevation in circulating HA levels in Stab2-deficient mice without any overt phenotype. Surprisingly, the metastasis of B16F10 melanoma cells to the lungs was markedly suppressed in the Stab2-deficient mice, whereas cell proliferation was not affected. Furthermore, administration of an anti-Stab2 antibody in Stab2+ mice elevated serum HA levels and prevented the metastasis of melanoma to the lung, and also suppressed spontaneous metastasis of mammary tumor and human breast tumor cells inoculated in the mammary gland. Administration of the antibody or high-dose HA in mice blocked the lodging of melanoma cells to the lungs. Furthermore, HA at high concentrations inhibited the rolling/tethering of B16 cells to lung endothelial cells. These results suggest that blocking Stab2 function prevents tumor metastasis by elevating circulating HA levels. Stab2 may be a potential target in antitumor therapy.

Hirose, Yoshikazu; Saijou, Eiko; Sugano, Yasuyoshi; Takeshita, Fumitaka; Nishimura, Satoshi; Nonaka, Hidenori; Chen, Yen-Rong; Sekine, Keisuke; Kido, Taketomo; Nakamura, Takashi; Kato, Shigeaki; Kanke, Toru; Nakamura, Koji; Nagai, Ryozo; Ochiya, Takahiro; Miyajima, Atsushi

2012-01-01

379

Inhibition of Stabilin-2 elevates circulating hyaluronic acid levels and prevents tumor metastasis.  

PubMed

Hyaluronic acid (HA) has been implicated in the proliferation and metastasis of tumor cells. However, most previous studies were conducted on extracellular matrix or pericellular HA, and the role of circulating HA in vivo has not been studied. HA is rapidly cleared from the bloodstream. The scavenger receptor Stabilin-2 (Stab2) is considered a major clearance receptor for HA. Here we report a dramatic elevation in circulating HA levels in Stab2-deficient mice without any overt phenotype. Surprisingly, the metastasis of B16F10 melanoma cells to the lungs was markedly suppressed in the Stab2-deficient mice, whereas cell proliferation was not affected. Furthermore, administration of an anti-Stab2 antibody in Stab2(+) mice elevated serum HA levels and prevented the metastasis of melanoma to the lung, and also suppressed spontaneous metastasis of mammary tumor and human breast tumor cells inoculated in the mammary gland. Administration of the antibody or high-dose HA in mice blocked the lodging of melanoma cells to the lungs. Furthermore, HA at high concentrations inhibited the rolling/tethering of B16 cells to lung endothelial cells. These results suggest that blocking Stab2 function prevents tumor metastasis by elevating circulating HA levels. Stab2 may be a potential target in antitumor therapy. PMID:22371575

Hirose, Yoshikazu; Saijou, Eiko; Sugano, Yasuyoshi; Takeshita, Fumitaka; Nishimura, Satoshi; Nonaka, Hidenori; Chen, Yen-Rong; Sekine, Keisuke; Kido, Taketomo; Nakamura, Takashi; Kato, Shigeaki; Kanke, Toru; Nakamura, Koji; Nagai, Ryozo; Ochiya, Takahiro; Miyajima, Atsushi

2012-02-27

380

European Stroke Prevention Study 2. Dipyridamole and acetylsalicylic acid in the secondary prevention of stroke 1 1 ESPS-2 Writing Committee  

Microsoft Academic Search

In 1988, we undertook a randomized, placebo-controlled, double-blind trial to investigate the safety and efficacy of low-dose acetylsalicylic acid (ASA), modified-release dipyridamole, and the two agents in combination for secondary prevention of ischemic stroke. Patients with prior stroke or transient ischemic attack (TIA) were randomized to treatment with ASA alone (50 mg daily), modified-release dipyridamole alone (400 mg daily), the

H. C. Diener; L. Cunha; C. Forbes; J. Sivenius; P. Smets; A. Lowenthal

1996-01-01

381

The PI3K/Akt and ERK1/2 signaling pathways mediate the erythropoietin-modulated calcium influx in kainic acid-induced epilepsy.  

PubMed

Erythropoietin (EPO) suppresses epileptogenesis and limits the neuronal damage associated with recurrent seizures, but the neurocellular mechanism is unclear. Dysregulation of intracellular calcium homeostasis is a key pathogenic event leading to the progression of epileptic activity, suggesting that EPO may suppress seizures by stabilizing intracellular calcium. In this study, we examined the effects of EPO on voltage-gated Ca(2+) influx in cultured rat hippocampal neurons and population spike (PS) amplitude in kainic acid (KA)-induced rats and the mechanisms responsible. KA injection markedly increased EPO and EPO receptor expression and the amplitude of PS in the hippocampal CA3 region, evoked by perforant pathway stimulation. Intracerebroventricular injection of exogenous rat recombinant EPO reversed KA-induced PS amplitude in the hippocampal CA3 region. Similarly, rat recombinant EPO pretreatment attenuates the increased voltage-gated calcium current's (I(Ca)) amplitude and density induced by KA in cultured hippocampal neurons. In contrast, transient transfection of rat EPO small interfering RNS (siRNA) further enhanced I(Ca) amplitude and density in the presence of KA, whereas a scrambled control siRNA had no effect. Further, EPO activates the PI3K and ERK1/2 pathways in cultured hippocampal neurons, and the PI3K/Akt inhibitor LY294002 and ERK1/2 inhibitor U0126 both blocked, at least in part, the suppressive effect of exogenous EPO on KA-induced calcium currents. This study indicates that both endogenous and exogenous EPO decrease KA-sensitive calcium influx and concomitant hyperexcitability in hippocampal neurons. The results also demonstrate that the PI3K/Akt and ERK1/2 signaling pathways mediate the EPO-modulated calcium influx in KA-induced epilepsy. PMID:23518641

Zheng, Honghua; Wang, Xiaojing; Tang, Zhengang; Zheng, Weihong; Li, Zhengli

2013-04-17

382

Cigarette smoking-induced coronary vasoconstriction in atherosclerotic coronary artery disease and prevention by calcium antagonists and nitroglycerin.  

PubMed

In patients with coronary artery disease, cigarette smoking increases myocardial oxygen demand but may cause an inappropriate alpha-adrenergically mediated fall in myocardial oxygen supply. This study was performed to determine if smoking-induced coronary vasoconstriction is prevented by nitroglycerin, verapamil or nifedipine treatment. In 25 smokers with coronary artery disease (20 men, 5 women, aged 32 to 65 years), heart rate-systolic arterial pressure double product and coronary sinus blood flow (thermodilution) were measured before and during smoking both before and 30 to 60 minutes after administration of saline solution (n = 5, control subjects); nifedipine, 10 mg sublingually (n = 6); verapamil, 10 mg intravenously (n = 7); or nitroglycerin, 0.4 mg sublingually (n = 7). During the first smoking period, double product increased, but coronary sinus flow did not change or decreased. During the second smoking period, in the control subjects double product and coronary sinus flow responded in a manner similar to that observed previously. In those given nifedipine, double product did not change, but coronary sinus flow increased (-4 +/- 5% during the first smoking period [before nifedipine] and 17 +/- 12% during the second period [after nifedipine], p less than 0.01). In those given verapamil, double product and coronary sinus flow increased during smoking (-12 +/- 8% during the first smoking period [before verapamil], 10 +/- 9% during the second period [after verapamil], p less than 0.01).(ABSTRACT TRUNCATED AT 250 WORDS) PMID:3101478

Winniford, M D; Jansen, D E; Reynolds, G A; Apprill, P; Black, W H; Hillis, L D

1987-02-01

383

Hydrogen sulfide prevents hypoxia-induced apoptosis via inhibition of an H2O2-activated calcium signaling pathway in mouse hippocampal neurons.  

PubMed

Hydrogen sulfide (H(2)S), an endogenous gaseous mediator, has been shown to exert protective effects against damage to different organs in the human body caused by various stimuli. However, the potential effects of H(2)S on hypoxia-induced neuronal apoptosis and its mechanisms remain unclear. Here, we exposed mouse hippocampal neurons to hypoxic conditions (2% O(2), 5% CO(2) and 93% N(2) at 37 °C) to establish a hypoxic cell model. We found that 4-h hypoxia treatment significantly increased intracellular reactive oxygen species (ROS) levels, and pretreatment with NaHS (a source of H(2)S) for 30 min suppressed hypoxia-induced intracellular ROS elevation. The hypoxia treatment significantly increased cytosolic calcium ([Ca(2+)](i)), and pretreatment with NaHS prevented the increase in [Ca(2+)](i). Additionally, polyethylene glycol (PEG)-catalase (a H(2)O(2) scavenger) but not PEG-SOD (an O(2)(-) scavenger) conferred an inhibitory effect similar to H(2)S on the hypoxia-induced increase in [Ca(2+)](i). Furthermore, we found that pretreatment with NaHS could significantly inhibit hypoxia-induced neuronal apoptosis, which was also inhibited by PEG-catalase or the inositol 1,4,5-triphosphate (IP(3)) receptor blocker xestospongin C. Taken together, these findings suggest that H(2)S inhibits hypoxia-induced apoptosis through inhibition of a ROS (mainly H(2)O(2))-activated Ca(2+) signaling pathway in mouse hippocampal neurons. PMID:22846576

Luo, Yougen; Liu, Xiaoai; Zheng, Qisheng; Wan, Xiaomei; Ouyang, Shuichang; Yin, Yedong; Sui, Xiaojing; Liu, Jianjun; Yang, Xifei

2012-07-27

384

Calcium and Vitamin D  

Technology Transfer Automated Retrieval System (TEKTRAN)

Adequate intakes of vitamin D and calcium are essential preventative measures and essential components of any therapeutic regimen for osteoporosis. Vitamin D is also important for the prevention of falls. Current evidence suggests that a 25-hydroxyvitamin D level of 75 nmol/L (30 ng/ml) or higher ...

385

Tachikawa project for prevention of posttraumatic stress disorder with polyunsaturated fatty acid (TPOP): study protocol for a randomized controlled trial  

PubMed Central

Background Preclinical and clinical studies suggest that supplementation with omega-3 fatty acids after trauma might reduce subsequent posttraumatic stress disorder (PTSD). To date, we have shown in an open trial that PTSD symptoms in critically injured patients can be reduced by taking omega-3 fatty acids, hypothesized to stimulate hippocampal neurogenesis. The primary aim of the present randomized controlled trial is to examine the efficacy of omega-3 fatty acid supplementation in the secondary prevention of PTSD following accidental injury, as compared with placebo. This paper describes the rationale and protocol of this trial. Methods/design The Tachikawa Project for Prevention of Posttraumatic Stress Disorder with Polyunsaturated Fatty Acid (TPOP) is a double-blinded, parallel group, randomized controlled trial to assess whether omega-3 fatty acid supplementation can prevent PTSD symptoms among accident-injured patients consecutively admitted to an intensive care unit. We plan to recruit accident-injured patients and follow them prospectively for 12 weeks. Enrolled patients will be randomized to either the omega-3 fatty acid supplement group (1,470 mg docosahexaenoic acid and 147 mg eicosapentaenoic acid daily) or placebo group. Primary outcome is score on the Clinician-Administered PTSD Scale (CAPS). We will need to randomize 140 injured patients to have 90% power to detect a 10-point difference in mean CAPS scores with omega-3 fatty acid supplementation compared with placebo. Secondary measures are diagnosis of PTSD and major depressive disorder, depressive symptoms, physiologic response in the experiment using script-driven imagery and acoustic stimulation, serum brain-derived neurotrophic factor, health-related quality of life, resilience, and aggression. Analyses will be by intent to treat. The trial was initiated on December 13 2008, with 104 subjects randomized by November 30 2012. Discussion This study promises to be the first trial to provide a novel prevention strategy for PTSD among traumatized people. Trial registration ClinicalTrials.gov Identifier NCT00671099

2013-01-01

386

Membrane chaperone Shr3 assists in folding amino acid permeases preventing precocious ERAD.  

PubMed

The yeast endoplasmic reticulum (ER) membrane-localized chaperone Shr3 plays a critical role in enabling amino acid permeases (AAPs) to fold and attain proper structures required for functional expression at the plasma membrane. In the absence of Shr3, AAPs specifically accumulate in the ER, where despite the correct insertion of their 12 transmembrane segments (TMSs), they aggregate forming large molecular weight complexes. We show that Shr3 prevents aggregation and facilitates the functional assembly of independently coexpressed N- and C-terminal fragments of the general AAP Gap1. Shr3 interacts with and maintains the first five TMSs in a conformation that can posttranslationally assemble with the remaining seven TMSs. We also show that Doa10- and Hrd1-dependent ER-associated degradation (ERAD) pathways redundantly degrade AAP aggregates. In combination, doa10Delta hrd1Delta mutations stabilize AAP aggregates and partially suppress amino acid uptake defects of shr3 mutants. Consequently, in cells with impaired ERAD, AAPs are able to attain functional conformations independent of Shr3. These findings illustrate that folding and degradation are tightly coupled processes during membrane protein biogenesis. PMID:17325204

Kota, Jhansi; Gilstring, C Fredrik; Ljungdahl, Per O

2007-02-26

387

Tauroursodeoxycholic acid (TUDCA) supplementation prevents cognitive impairment and amyloid deposition in APP/PS1 mice.  

PubMed

Alzheimer's disease (AD) is a neurodegenerative disease hallmarked by extracellular A?(1-42) containing plaques, and intracellular neurofibrillary tangles (NFT) containing hyperphosphorylated tau protein. Progressively, memory deficits and cognitive disabilities start to occur as these hallmarks affect hippocampus and frontal cortex, regions highly involved in memory. Connective tissue growth factor (CTGF) expression, which is high in the vicinity of A? plaques and NFTs, was found to influence ?-secretase activity, the molecular crux in A?(1-42) production. Tauroursodeoxycholic acid (TUDCA) is an endogenous bile acid that downregulates CTGF expression in hepatocytes and has been shown to possess therapeutic efficacy in neurodegenerative models. To investigate the possible in vivo therapeutic effects of TUDCA, we provided 0.4% TUDCA-supplemented food to APP/PS1 mice, a well-established AD mouse model. Six months of TUDCA supplementation prevented the spatial, recognition and contextual memory defects observed in APP/PS1 mice at 8 months of age. Furthermore, TUDCA-supplemented APP/PS1 mice displayed reduced hippocampal and prefrontal amyloid deposition. These effects of TUDCA supplementation suggest a novel mechanistic route for Alzheimer therapeutics. PMID:22974733

Lo, Adrian C; Callaerts-Vegh, Zsuzsanna; Nunes, Ana F; Rodrigues, Cecília M P; D'Hooge, Rudi

2012-09-10

388

Gallic acid prevents memory deficits and oxidative stress induced by intracerebroventricular injection of streptozotocin in rats.  

PubMed

In the present study, we evaluated the effects of gallic acid (GA; 30mg/kg, orally, once daily for 26days starting from day 5 prior to streptozotocin injection) on cognitive impairment and cerebral oxidative stress induced by intracerebroventricular-streptozotocin (ICV-STZ; bilaterally, two doses of 3mg/kg) injection as an animal model of sporadic Alzheimers type (SDAT) in rats. The results showed that ICV-STZ-injection reduced the passive avoidance and spatial memory performance associated with decreased non-enzymatic [total thiol concentration, -58.5%, -50.7%] and enzymatic [superoxide dismutase (SOD, -30.2%, -32.9%), catalase (CAT, -43.5%, -50.7%), glutathione peroxidase (GPx, -57.1%, -61.7%)] activities and increased the level of thio-barbituric acid reactive species (TBARS, +103.5%, +82.5%) in the hippocampus and cerebral cortex, respectively. In contrast, chronic administration of GA significantly prevented cognitive deficits and biochemical alterations in the ICV-STZ rats. These findings highlight the beneficial role of GA in the ICV-STZ rats via enhancement of cerebral antioxidant defense system. Thus, it may have a therapeutic value for the treatment of SDAT. PMID:24036471

Mansouri, Mohammad Taghi; Naghizadeh, Bahareh; Ghorbanzadeh, Behnam; Farbood, Yaghoub; Sarkaki, Alireza; Bavarsad, Kowsar

2013-09-11

389

The effects of taurochenodeoxycholic acid in preventing pulmonary fibrosis in mice.  

PubMed

The present study prepared the pulmonary fibrosis model in mice by using Bleomycin and carry out the investigations on the effects of taurochenodeoxycholic acid (TCDCA) in preventing pulmonary fibrosis in mice. Expression profiles of the bile acid receptors in the lung of mice FXR? and TGR5 were examined, and pulmonary coefficient, pathohistology as well as expression of TNF-?, MMP-2, MMP-9 and TIMP-2 in pulmonary fibrosis mice. The results showed that FXR? and TGR5 simultaneously expressed in the lung of the mice; TCDCA in dosages of 0.05 and 0.1g/kg can extremely significantly decrease the pulmonary coefficient in the model mice (P>0.01), TCDCA in a dosage of 0.2g/kg significantly decreased the pulmonary coefficient in the model mice (P<0.05); TCDCA in dosages of 0.05 and 0.1g/kg significantly reduce the pathological damages on their lungs; TCDCA can extremely significantly decrease the expression levels of TNF-? and TIMP-2 in pulmonary tissues in the pulmonary fibrosis mice (P>0.01), the expression level of MMP-9 extremely significantly increased (P>0.01), while it has no significant effects on MMP2. The results as mentioned above indicated that TCDCA had antagonistic actions on pulmonary fibrosis in mice. PMID:23811455

Zhou, Chuan; Shi, Youfei; Li, Jinlian; Zhang, Wen; Wang, Yanmin; Liu, Yan; Liu, Jianzhu

2013-07-01

390

Lysophosphatidic acid-induced calcium mobilization and proliferation in kidney proximal tubular cells.  

PubMed

Patients with proteinuria tend to develop progressive renal disease with proximal tubular cell atrophy and interstitial scarring. It has been suggested that the nephrotoxicity of albuminuric states may be due to the protein molecule itself or by lipids, such as lysophosphatidic acid (LPA), that albumin carries. LPA was found to cause a transient increase in intracytoplasmic free Ca2+ ([Ca2+]i) in opossum kidney proximal tubule cells (OK) that was maximal at 100 microM LPA and was dose dependent with an EC50 of 2.6 x 10(-6) M. This Ca2+ mobilization was from both internal stores and across the plasma membrane and was pertussis toxin (PTX) insensitive. Treatment of OK cells with 100 microM LPA for 5 min was found to cause a twofold increase in [3H]thymidine incorporation and a three- to fivefold increase over control after 24 h. This was highly PTX sensitive and insensitive to pretreatment with the tyrosine kinase inhibitors genistein and herbimycin A. These findings may be of significance in the progression of renal disease and indicate the potential importance of lipids in modulating proximal tubule cell function and growth. PMID:9950949

Dixon, R J; Young, K; Brunskill, N J

1999-02-01

391

Inactivation of calcium-dependent lactic acid bacteria phages by phosphates.  

PubMed

The capacity of three phosphates to interrupt the lytic cycle of four specific autochthonal bacteriophages of lactic acid bacteria used as starters was assayed. The phosphates used (polyphosphates A and B and sodium tripolyphosphate-high solubility [TAS]) were selected on the basis of their capacity to sequester divalent cations, which are involved in the lytic cycle of certain bacteriophages. The assays were performed in culture media (deMan Rogosa Sharpe and Elliker broths) and reconstituted (10%, wt/vol) commercial skim milk to which phosphates had been added at concentrations of 0.1, 0.3, and 0.5% (wt/vol). Phosphate TAS was the most inhibitory one, since it was able to inhibit the lytic cycle of all bacteriophages studied, in both broths and milk. In broth, polyphosphates A and B inhibited the lytic cycle of only two bacteriophages at the maximal concentration used (0.5%), whereas in milk, they were not capable of maintaining the same inhibitory effect. PMID:17612087

Suárez, V B; Capra, M L; Rivera, M; Reinheimer, J A

2007-06-01

392

Arachidyl amido cholanoic acid (aramchol) is a cholesterol solubilizer and prevents the formation of cholesterol gallstones in inbred mice  

Microsoft Academic Search

We have recently synthesized fatty acid bile acid conjugates (FABAC) that were able to reduce and retard cholesterol crystallization\\u000a in model and human biles. When given orally, they prevented the formation of cholesterol crystals in the bile of hamsters.\\u000a The aim of the present study was to determine whether the FABAC are cholesterol solubilizers, whether they can dissolve pre-existing\\u000a crystals,

Tuvia Gilat; Alicia Leikin-Frenkel; Ilana Goldiner; Hava Laufer; Zamir Halpern; Fred M. Konikoff

2001-01-01

393

Prolongation of calcium action potentials by gamma-aminobutyric acid in primary sensory neurones of lamprey.  

PubMed Central

Intracellular recordings from primary mechanosensory neurones (dorsal cells) in the lamprey spinal cord were used to test the membrane effects of a variety of putative neuromodulatory agents. gamma-Aminobutyric acid (GABA) produced a dose-dependent increase in the duration of mixed Na-Ca or pure Ca action potentials in these cells. L-Glutamate and glycine produced minimal broadening of Ca action potentials. Acetylcholine, noradrenaline, serotonin, met-enkephalin, D-glutamate and dopamine had no effect. The pharmacology of GABA's action appeared to be complex. While the GABAA receptor antagonists, bicuculline, picrotoxin and curare, did not block GABA's effect, both the GABAA receptor agonist, muscimol, and the GABAB-receptor agonist, baclofen, occasionally broadened Ca action potentials in these cells. GABA had no effect on the resting potential, passive current-voltage (I-V) characteristics and pure Na action potential of dorsal cells, ruling out an action on passive membrane channels, transmitter-activated channels, or on those voltage-dependent channels activated during the Na action potential. Thus, GABA affected dorsal cells only when a significant Ca current was evident. GABA appeared not to increase the conductance of the Ca channels since its action was accompanied by an increase in input resistance, suggesting an inhibition of Ca-dependent conductance that normally acts to repolarize the membrane during a Ca action potential. An inhibitory effect of GABA on a Ca-dependent Cl conductance was ruled out in experiments where the Cl gradient was altered by removal of extracellular Cl without affecting GABA-induced Ca action potential prolongation. Dorsal cells have a prominent Ca-dependent K conductance (gK(Ca], and it is this conductance that GABA may inhibit. Consistent with this was the observation that the hyperpolarizing after-potential that follows Ca action potentials in dorsal cells, which reflects gK(Ca) in these cells and whose duration is normally increased when the Ca action potential duration increases, was not prolonged when the Ca action potential was broadened by GABA. Further, the failure of GABA to prolong Ba action potentials was consistent with this proposed mechanism of action, since Ba apparently does not activate gK(Ca) in these cells. Forskolin, a specific adenylate cyclase activator, caused broadening of Ca action potentials in lamprey dorsal cells comparable in magnitude to that of GABA. Thus, an increase in intracellular cyclic AMP is a candidate for the intracellular mediator of GABA's effect on these cells.

Leonard, J P; Wickelgren, W O

1986-01-01

394

Recurrent vesical calculi, hypercalciuria, and biochemical evidence of increased bone resorption in an adult male with paraplegia due to spinal cord injury: is there a role for intermittent oral disodium etidronate therapy for prevention of calcium phosphate bladder stones?  

Microsoft Academic Search

Study design:Clinical case report with comments by colleagues from Sweden, Poland, Spain, Brazil, Japan, Belgium and Switzerland.Objectives:To discuss the role of disodium etidronate therapy for prevention of calcium phosphate vesical calculi in persons with spinal cord injury, who have hypercalciuria and biochemical evidence of increased bone resorption.Setting:Regional Spinal Injuries Centre, Southport, UK.Methods:A 21-year-old male sustained paraplegia (T-10; ASIA scale: A)

S Vaidyanathan; I D Watson; O Jonsson; A Z Buczynski; F Grases; I P Heilberg; T Yasui; J J Wyndaele; K Tozawa; K Kohri; B Schurch; P L Hughes; G Singh; B M Soni; P Sett; W D Fraser

2005-01-01

395

Effect of molecular weight and concentration of poly(acrylic acid) on the formation of a polymeric calcium phosphate cement.  

PubMed

Previous investigations have noted that the tetracalcium phosphate (TTCP)/dicalcium phosphate anhydrous (DCPA) apatite forming calcium phosphate cement (CPC) possesses many favorable properties from a biomaterials standpoint. Despite these positive properties various shortcomings have limited clinical usage of these materials and fostered investigations into the effect of numerous additives. The present study concerns the effect of poly(acrylic acid) (PAA) addition and the influence of factors such as molecular weight and concentration of the additive on the properties of the set cement. One-way ANOVA was conducted using all results obtained, to firstly derive the influence of concentration within each molecular weight group, and secondly to derive the influence of molecular weight within each concentration group. All investigated mechanical properties were influenced by both molecular weight and concentration of the additive. Higher molecular weights tended to result in cements with shorter setting times and higher compressive, diametral and biaxial flexural strengths than their lower molecular weight counterparts. The effect of concentration on the properties of the set cement however was somewhat more complex, a negative correlation was observed between the initial setting time and PAA concentration. In regards to the final setting time, any correlation with concentration was difficult to derive as a consequence of the highly brittle nature of cements made with low concentrations. In regard to mechanical properties, intermediate concentrations tended to give higher strengths than both their higher and lower counterparts, however the exact pattern was largely specific to the mechanical strength test employed. We conclude that molecular weight and concentration of PAA influence the setting behavior and final mechanical properties of the TTCP/DCPA cement, and that selection of an appropriate PAA solution can lead to the production of cements with properties superior to those formed in the absence of the polymer. PMID:15348393

Majekodunmi, A O; Deb, S; Nicholson, J W

2003-09-01

396

Cross-talk between calcium-calmodulin and nitric oxide in abscisic acid signaling in leaves of maize plants.  

PubMed

Using pharmacological and biochemical approaches, the signaling pathways between hydrogen peroxide (H(2)O(2)), calcium (Ca(2+))-calmodulin (CaM), and nitric oxide (NO) in abscisic acid (ABA)-induced antioxidant defense were investigated in leaves of maize (Zea mays L.) plants. Treatments with ABA, H(2)O(2), and CaCl(2) induced increases in the generation of NO in maize mesophyll cells and the activity of nitric oxide synthase (NOS) in the cytosolic and microsomal fractions of maize leaves. However, such increases were blocked by the pretreatments with Ca(2+) inhibitors and CaM antagonists. Meanwhile, pretreatments with two NOS inhibitors also suppressed the Ca(2+)-induced increase in the production of NO. On the other hand, treatments with ABA and the NO donor sodium nitroprusside (SNP) also led to increases in the concentration of cytosolic Ca(2+) in protoplasts of mesophyll cells and in the expression of calmodulin 1 (CaM1) gene and the contents of CaM in leaves of maize plants, and the increases induced by ABA were reduced by the pretreatments with a NO scavenger and a NOS inhibitor. Moreover, SNP-induced increases in the expression of the antioxidant genes superoxide dismutase 4 (SOD4), cytosolic ascorbate peroxidase (cAPX), and glutathione reductase 1 (GR1) and the activities of the chloroplastic and cytosolic antioxidant enzymes were arrested by the pretreatments with Ca(2+) inhibitors and CaM antagonists. Our results suggest that Ca(2+)-CaM functions both upstream and downstream of NO production, which is mainly from NOS, in ABA- and H(2)O(2)-induced antioxidant defense in leaves of maize plants. PMID:18364679

Sang, Jianrong; Zhang, Aying; Lin, Fan; Tan, Mingpu; Jiang, Mingyi

2008-05-01

397

Cellular mechanisms by which lipoic acid confers protection during the early stages of cerebral ischemia: a possible role for calcium.  

PubMed

Lipoic acid (LA) is a naturally occurring compound and dietary supplement with powerful antioxidant properties. Although LA is neuroprotective in models of stroke, little is known about the cellular mechanisms by which it confers protection during the early stages of ischemia. Here, using a rat model of permanent middle cerebral artery occlusion (MCAO), we demonstrated that administration of LA 30 min prior to stroke, reduces infarct volume in a dose dependent manner. Whole-cell patch clamp techniques in rat brain slices were used to determine if LA causes any electrophysiological alterations in either healthy neurons or neurons exposed to oxygen and glucose deprivation (OGD). In healthy neurons, LA (0.005 mg/ml and 0.05 mg/ml) did not significantly change resting membrane potential, threshold or frequency of action potentials or synaptic transmission, as determined by amplitude of excitatory post synaptic currents (EPSCs). Similarly, in neurons exposed to OGD, LA did not alter the time course to loss of EPSCs. However, there was a significant delay the onset of anoxic depolarization as well as in the time course of the depolarization. Next, intracellular calcium (Ca(2+)) levels were monitored in isolated neurons using fura-2. Pretreatment with 0.005 mg/ml and 0.05 mg/ml LA for 30 min and 6 h did not significantly alter resting Ca(2+) levels or Ca(2+) response to glutamate (250 ?M). However, pretreatment with 0.5 mg/ml LA for 6 h significantly increased resting Ca(2+) levels and significantly decreased the Ca(2+) response to glutamate. In summary, these findings suggest that LA does not affect neuronal physiology under normal conditions, but can protect cells from an ischemic event. PMID:21185885

Richard, Marc J P; Connell, Barry J; Khan, Bobby V; Saleh, Tarek M

2010-12-24

398

Inhibition of fatty acid biosynthesis prevents adipocyte lipotoxicity on human osteoblasts in vitro  

PubMed Central

Although increased bone marrow fat in age-related bone loss has been associated with lower trabecular mass, the underlying mechanism responsible remains unknown. We suggested that marrow adipocytes exert a lipotoxic effect on osteoblast function and survival through the reversible biosynthesis of fatty acids (FA) into the bone marrow microenvironment. We have used a two-chamber system to co-culture normal human osteoblasts (NHOst) with differentiating pre-adipocytes in the absence or presence of an inhibitor of FA synthase (cerulenin) and separated by an insert that allowed unidirectional trafficking of soluble factors only and prevented direct cell–cell contact. Supernatants were assayed for the presence of FA using mass spectophotometry. After 3 weeks in co-culture, NHOst showed significantly lower levels of differentiation and function based on lower mineralization and expression of alkaline phosphatase, osterix, osteocalcin and Runx2. In addition, NHOst survival was affected by the presence of adipocytes as determined by MTS-formazan and TUNEL assays as well as higher activation of caspases 3/7. These toxic effects were inhibited by addition of cerulenin. Furthermore, culture of NHOst with either adipocyte-conditioned media alone in the absence of adipocytes themselves or with the addition of the most predominant FA (stearate or palmitate) produced similar toxic results. Finally, Runx2 nuclear binding was affected by addition of either adipocyte conditioned media or FA into the osteogenic media. We conclude that the presence of FA within the marrow milieu can contribute to the age-related changes in bone mass and can be prevented by the inhibition of FA synthase.

Elbaz, Alexandre; Wu, Xiying; Rivas, Daniel; Gimble, Jeffrey M.; Duque, Gustavo

2009-01-01

399

A single residue in a novel ADP-ribosyl cyclase controls production of the calcium-mobilizing messengers cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate.  

PubMed

Cyclic ADP-ribose and nicotinic acid adenine dinucleotide phosphate are ubiquitous calcium-mobilizing messengers produced by the same family of multifunctional enzymes, the ADP-ribosyl cyclases. Not all ADP-ribosyl cyclases have been identified, and how production of different messengers is achieved is incompletely understood. Here, we report the cloning and characterization of a novel ADP-ribosyl cyclase (SpARC4) from the sea urchin, a key model organism for the study of calcium-signaling pathways. Like several other members of the ADP-ribosyl cyclase superfamily, SpARC4 is a glycoprotein targeted to the plasma membrane via a glycosylphosphatidylinositol anchor. However, unlike most other members, SpARC4 shows a remarkable preference for producing cyclic ADP-ribose over nicotinic acid adenine dinucleotide phosphate. Mutation of a single residue (tyrosine 142) within a noncanonical active site reversed this striking preference. Our data highlight further diversification of this unusual enzyme family, provide mechanistic insight into multifunctionality, and suggest that different ADP-ribosyl cyclases are fine-tuned to produce specific calcium-mobilizing messengers. PMID:20385553

Ramakrishnan, Latha; Muller-Steffner, Hélène; Bosc, Christophe; Vacquier, Victor D; Schuber, Francis; Moutin, Marie-Jo; Dale, Leslie; Patel, Sandip

2010-04-12

400

Five year study of etidronate and/or calcium as prevention and treatment for osteoporosis and fractures in patients with asthma receiving long term oral and/or inhaled glucocorticoids  

PubMed Central

Background: Glucocorticoids are associated with a reduction in bone density and an increased risk of fracture. Concurrent treatment with bisphosphonates reduces bone loss and may prevent fractures. A randomised study was performed to determine whether treatment with cyclical etidronate and/or calcium for 5 years prevents fractures or reverses/reduces bone loss in patients receiving glucocorticoid treatment for asthma. Methods: A multicentre, randomised, parallel group comparison of etidronate alone, calcium alone, etidronate + calcium, and no treatment, with stratification according to level of glucocorticoid exposure was carried out in 39 chest clinics in the UK. Three hundred and forty nine postmenopausal female and male outpatients with asthma aged 50–70 years were randomised. The main outcome measures were fractures and changes in bone mineral density (BMD). Results: Overall, 8% of the patients experienced symptomatic fractures and 17.5% developed either a symptomatic fracture and/or a semiquantitative vertebral fracture by the end of 5 years There were no significant differences between the four treatment groups. Comparing etidronate with no etidronate, the rates of new fractures were not significantly different for symptomatic fractures (OR 1.07 (95% CI 0.46 to 2.47)) or for any fractures (OR 0.82 (95% CI 0.45 to 1.47)). For the comparison of calcium with no calcium the corresponding ORs were 1.43 (95% CI 0.62 to 3.33) and 0.91 (95% CI 0.50 to 1.63). In post hoc analysis the effect of etidronate was greater in women than in men (interaction p value 0.02) with the fracture incidence roughly halved (OR 0.39, 95% CI 0.14 to 0.99). Etidronate increased BMD at the lumbar spine by 4.1% (p = 0.001) while calcium had no significant effect. At the proximal femur the effects of treatment were not significant (relative increases etidronate 1.6%; calcium 1.1%). The rate of new fractures in patients with fractures at entry (23.7%) was higher than in those without fractures at entry (14.3%): OR 1.87 (95% CI 1.06 to 3.07). No association was found between change in BMD and new fractures. Conclusions: In patients receiving glucocorticoids for asthma etidronate significantly increased BMD over 5 years at the lumbar spine but not at the hip and had little if any protective effect against fractures, except possibly in postmenopausal women. The effects of calcium were not significant. Combination treatment had no advantage but increased unwanted effects.

Campbell, I; Douglas, J; Francis, R; Prescott, R; Reid, D

2004-01-01

401

Lanthanum actions on excitatory amino acid-gated currents and voltage-gated calcium currents in rat dorsal horn neurons.  

PubMed Central

1. The effects of lanthanum ions (La3+) on voltage-gated calcium currents (VGCCs) and excitatory amino acid (EAA)-evoked currents were characterized using cultured or acutely dissociated neurons from the dorsal horn of the rat spinal cord. 2. VGCCs evoked by depolarizing voltage steps were reversibly blocked by La3+ with an apparent log dissociation constant Kd of 163 nM. 3. La3+ antagonism of currents evoked by NMDA was less potent, with an EC50 (half-maximal effective concentration) of 2 microM. The block of NMDA-evoked currents was voltage independent and non-competitive with respect to activation of the NMDA receptor. 4. La3+ had both enhancing and blocking actions on currents evoked by kainate or by quisqualate; concentrations of La3+ between 1 and 100 microM enhanced kainate- and quisqualate-evoked currents, while the currents were blocked by concentrations of La3+ greater than 100 microM. Both the blocking and the enhancing actions of La3+ were independent of membrane potential. 5. An enhancing dose of La3+ shifted the dose-response curve for kainate to lower concentrations of agonist without changing the maximum evoked current, and a similar leftward shift of the quisqualate dose-response curve occurred at non-saturating concentrations of quisqualate. This enhancement might occur either due to increased affinity of the receptor for ligand, or by increased concentration of ligand at the membrane surface; the latter effect could result from a reduction in the membrane surface charge. 6. The divalent cation Zn(2+)-mimicked the effects of La3+ on excitatory amino acid-evoked currents in dorsal horn neurons, but was less potent both as a blocker and as an enhancer. This suggests that La3+ and Zn2+ could act with different potencies at the same site or sites, and that La3+ may be a useful probe for the mechanisms of Zn2+ effects. 7. Since La3+ enhances kainate- and quisqualate-evoked responses at the same concentrations at which it suppresses VGCCs (and NMDA-gated currents), it can be a useful probe for separating VGCC activation from kainate- and quisqualate-induced depolarizations in experiments where voltage clamp is impractical. Images Fig. 1

Reichling, D B; MacDermott, A B

1991-01-01

402

Comparison of blood ionized calcium and acid-base variables in samples obtained from different sampling sites in dairy cows.  

PubMed

Ionized calcium (Ca2+) concentrations, pH, blood gas tensions (pCO2 and pO2), base excess (BE), and bicarbonate (HCO3-) concentrations were determined and standard ionized calcium (stCa2+) concentrations were calculated (Ca2+ corrected to pH 7.4) for the blood withdrawn from the jugular vein, the coccygeal vein or coccygeal artery and the milk vein in 29 clinically healthy post-partum dairy cows. The blood withdrawal site had no significant effect on the blood ionized calcium and standard ionized calcium (mean differences among the blood samples varied between 0.01 and 0.05 mmol/l), or on bicarbonate concentrations or base excess. pH, pCO2 and pO2 were significantly lower or higher in samples taken from the coccygeal vein compared to other venous blood samples. PMID:10399485

Bajcsy, A C; Bartyik, J; Szenci, O

1999-05-01

403

Prevention of postoperative air leakage from lungs using a purified human collagen membrane–polyglycolic acid sheet  

Microsoft Academic Search

Background. Human amnion has useful biomedical applications because it contains a large amount of human collagen fibers. We prepared purified human collagen membrane (HCM) from human amnion and used it to develop a new sheet by combining it with synthetic bioabsorbable polyglycolic acid (PGA) mesh. We evaluated its efficacy in preventing air leakage from the lungs of dogs.Methods. In 20

Toru Tsuda; Tatsuo Nakamura; Yasumichi Yamamoto; Masayoshi Teramachi; Tetsuya Kiyotani; Yong Ho Lee; Yasuhiko Shimizu

1999-01-01

404

Intestinal epithelial cell accumulation of the cancer preventive polyphenol ellagic acid—extensive binding to protein and DNA  

Microsoft Academic Search

Ellagic acid (EA), a polyphenol present in many berries, has been demonstrated to be preventive of esophageal cancer in animals both at the initiation and promotion stages. To be able to extrapolate these findings to humans we have studied the transcellular absorption and epithelial cell accumulation of [14C]EA in the human intestinal Caco-2 cells. The apical (mucosal) to basolateral (serosal)

Alexander C Whitley; Gary D Stoner; Michael V Darby; Thomas Walle

2003-01-01

405

L-Acetyl Carnitine Infusion to Prevent Glucose and Fatty Acid Oxidation during Myocardial Ischemia, Anoxia, and Other Diseases.  

National Technical Information Service (NTIS)

The invention provides a method of preventing the accumulation of the toxic products of glucose and fatty acid metabolism during myocardial ischemia and other diseases by infusng L-acetyl carnitine or its racemic mixture with D-acetyl carnitine into the b...

A. L. Shug

1979-01-01

406

Does an Aspirin a day keep the doctor away? Acetylsalicylic acid for the primary prevention of cardiovascular disease  

Microsoft Academic Search

Acetylsalicylic acid was introduced to the pharmaceutical market just over 100 years ago. Although it was originally intended for use as an analgesic, physicians quickly realized it provided many other therapeutic benefits. Dr Law - rence Craven first suggested ASA could prevent cardiovascular events with his publication of a large case series in 1950. Since then, several large randomized controlled

Michael Bayliss; Andrew Ignaszewski

2010-01-01

407

Abscisic acid and CO2 signalling via calcium sensitivity priming in guard cells, new CDPK mutant phenotypes and a method for improved resolution of stomatal stimulus-response analyses  

PubMed Central

Background Stomatal guard cells are the regulators of gas exchange between plants and the atmosphere. Ca2+-dependent and Ca2+-independent mechanisms function in these responses. Key stomatal regulation mechanisms, including plasma membrane and vacuolar ion channels have been identified and are regulated by the free cytosolic Ca2+ concentration ([Ca2+]cyt). Scope Here we show that CO2-induced stomatal closing is strongly impaired under conditions that prevent intracellular Ca2+ elevations. Moreover, Ca2+ oscillation-induced stomatal closing is partially impaired in knock-out mutations in several guard cell-expressed Ca2+-dependent protein kinases (CDPKs) here, including the cpk4cpk11 double and cpk10 mutants; however, abscisic acid-regulated stomatal movements remain relatively intact in the cpk4cpk11 and cpk10 mutants. We further discuss diverse studies of Ca2+ signalling in guard cells, discuss apparent peculiarities, and pose novel open questions. The recently proposed Ca2+ sensitivity priming model could account for many of the findings in the field. Recent research shows that the stomatal closing stimuli abscisic acid and CO2 enhance the sensitivity of stomatal closing mechanisms to intracellular Ca2+, which has been termed ‘calcium sensitivity priming’. The genome of the reference plant Arabidopsis thaliana encodes for over 250 Ca2+-sensing proteins, giving rise to the question, how can specificity in Ca2+ responses be achieved? Calcium sensitivity priming could provide a key mechanism contributing to specificity in eukaryotic Ca2+ signal transduction, a topic of central interest in cell signalling research. In this article we further propose an individual stomatal tracking method for improved analyses of stimulus-regulated stomatal movements in Arabidopsis guard cells that reduces noise and increases fidelity in stimulus-regulated stomatal aperture responses ( Box 1). This method is recommended for stomatal response research, in parallel to previously adopted blind analyses, due to the relatively small and diverse sizes of stomatal apertures in the reference plant Arabidopsis thaliana.

Hubbard, Katharine E.; Siegel, Robert S.; Valerio, Gabriel; Brandt, Benjamin; Schroeder, Julian I.

2012-01-01

408

Determination of amino acid sequence responsible for suppression of bone resorption by serum calcium-decreasing factor (caldecrin)  

Microsoft Academic Search

We previously reported on the serum calcium-decreasing activity of recombinant protein factor referred to as caldecrin [Tomomura et al. (1995) J. Biol. Chem. 270, 30315–30321]. To address the mechanism of this serum calcium-decreasing activity, we investigated the effect of rat caldecrin on osteoclastic bone-resorbing activity. Wild-type caldecrin suppressed resorption pit formation by osteoclast on a dentine slice in a dose-dependent

Akito Tomomura; Hirotaka Yamada; Kengo Fujimoto; Akemi Inaba; Setsuko Katoh

2001-01-01

409

Dietary Calcium Intake and The Prevalence of Calcium Supplement Use Among Well-Educated Women  

Microsoft Academic Search

LEARNING OUTCOME: To propagate among women the consumption of adequate dietary calcium to prevent osteoporosis.More women are seeking advice about calcium supplementation as awareness of osteoporosis increases. The purposes of this study were to determine the calcium content of women's diets to see if the recommended dietary allowance (RDA) was being met and to find out the prevalence of calcium

K. G. Galvacs

1997-01-01

410

Amlodipine prevents apoptotic cell death by correction of elevated intracellular calcium in a primary neuronal model of Batten disease (CLN3 disease).  

PubMed

CLN3 disease (Spielmeyer-Vogt-Sjogren-Batten disease) is a severe pediatric neurodegenerative disorder for which there is currently no effective treatment. The disease is characterized by progressive neuronal death, which may be triggered by abnormal intracellular calcium levels leading to neuronal apoptosis. Previously, we demonstrated reversal of the calcium effect in a neuroblastoma cell line using amlodipine and other calcium channel antagonists. In the present studies, we developed a CLN3 siRNA-inhibited primary rat neuron model to further study etoposide-induced calcium changes and apoptosis in CLN3 disease followed by recovery experiments with amlodipine. Our results show that intracellular calcium is significantly elevated in siRNA-inhibited cortical neurons after potassium chloride-induced depolarization. We were also able to show that amlodipine, a predominantly L-type dihydropyrimidine calcium channel antagonist can reverse the aberrant calcium elevations in this model of the disease. We performed an in situ TUNEL assay following etoposide-exposure to siRNA inhibited primary neurons, and apoptotic nuclei were detected providing additional evidence that increased neuronal apoptosis is associated with increased calcium levels. Amlodipine also reduced the absolute number of apoptotic cells in this experimental model. PMID:23769828

Warnock, Ashley; Tan, Lu; Li, Changhong; An Haack, Kristina; Narayan, Srinivas B; Bennett, Michael J

2013-06-13

411

A maize calcium-dependent protein kinase gene, ZmCPK4, positively regulated abscisic acid signaling and enhanced drought stress tolerance in transgenic Arabidopsis.  

PubMed

Calcium-dependent protein kinases (CDPKs) play essential roles in calcium-mediated signal transductions in plant response to abiotic stress. Several members have been identified to be regulators for plants response to abscisic acid (ABA) signaling. Here, we isolated a subgroup I CDPK gene, ZmCPK4, from maize. Quantitative real time PCR (qRT-PCR) analysis revealed that the ZmCPK4 transcripts were induced by various stresses and signal molecules. Transient and stable expression of the ZmCPK4-GFP fusion proteins revealed ZmCPK4 localized to the membrane. Moreover, overexpression of ZmCPK4 in the transgenic Arabidopsis enhanced ABA sensitivity in seed germination, seedling growth and stomatal movement. The transgenic plants also enhanced drought stress tolerance. Taken together, the results suggest that ZmCPK4 might be involved in ABA-mediated regulation of stomatal closure in response to drought stress. PMID:23911729

Jiang, Shanshan; Zhang, Dan; Wang, Li; Pan, Jiaowen; Liu, Yang; Kong, Xiangpei; Zhou, Yan; Li, Dequan

2013-07-19

412

The N-terminal 20-amino acid region of guanine nucleotide exchange factor Vav1 plays a distinguished role in T cell receptor-mediated calcium signaling.  

PubMed

Vav1 is a guanine nucleotide exchange factor (GEF) specifically expressed in hematopoietic cells. It consists of multiple structural domains and plays important roles in T cell activation. The other highly conserved isoforms of Vav family, Vav2 and Vav3, are ubiquitously expressed in human tissues including lymphocytes. All three Vav proteins activate Rho family small GTPases, which are involved in a variety of biological processes during T cell activation. Intensive studies have demonstrated that Vav1 is indispensable for T cell receptor (TCR)-mediated signal transduction, whereas Vav2 and Vav3 function as GEFs that overlap with Vav1 on TCR-induced cytoskeleton reorganization. T cells lacking Vav1 exhibited severe defect in TCR-mediated calcium elevation, indicating that the co-existing Vav2 and Vav3 did not compensate Vav1 in calcium signaling. What is the functional particularity of Vav1 in lymphocytes? In this study, we identified the N-terminal 20 amino acids of Vav1 in the calponin homology (CH) domain to be essential for its interaction with calmodulin (CaM) that leads to TCR-induced calcium mobilization. Substitution of the 1-20 amino acids of Vav1 with those of Vav2 or Vav3 abolished the association with CaM, and the N-terminal mutations of Vav1 failed to potentiate normal TCR-induced calcium mobilization, that in turn, suspended nuclear factor of activated T cells (NFAT) activation and IL-2 production. This study highlights the importance of the N-terminal 20 aa of Vav1 for CaM binding, and provides new insights into the distinguished and irreplaceable role of Vav1 in T cell activation and signal transduction. PMID:23271736

Li, Shi-Yang; Du, Ming-Juan; Wan, Ya-Juan; Lan, Bei; Liu, Yao-Hui; Yang, Yin; Zhang, Cui-Zhu; Cao, Youjia

2012-12-27

413

Sinomenine protects against ischaemic brain injury: involvement of co-inhibition of acid-sensing ion channel 1a and L-type calcium channels  

PubMed Central

BACKGROUND AND PURPOSE Sinomenine (SN), a bioactive alkaloid, has been utilized clinically to treat rheumatoid arthritis in China. Our preliminary experiments indicated that it could protect PC12 cells from oxygen-glucose deprivation-reperfusion (OGD-R), we thus investigated the possible effects of SN on cerebral ischaemia and the related mechanism. EXPERIMENTAL APPROACH Middle cerebral artery occlusion in rats was used as an animal model of ischaemic stroke in vivo. The mechanisms of the effects of SN were investigated in vitro using whole-cell patch-clamp recording, calcium imaging in PC12 cells and rat cortical neurons subjected to OGD-R. KEY RESULTS Pretreatment with SN (10 and 30 mg·kg?1, i.p.) significantly decreased brain infarction and the overactivation of calcium-mediated events in rats subjected to 2 h ischaemia followed by 24 h reperfusion. Extracellular application of SN inhibited the currents mediated by acid-sensing ion channel 1a and L-type voltage-gated calcium channels, in the rat cultured neurons, in a concentration-dependent manner. These inhibitory effects contribute to the neuroprotection of SN against OGD-R and extracellular acidosis-induced cytotoxicity. More importantly, administration of SN (30 mg·kg?1, i.p.) at 1 and 2 h after cerebral ischaemia also decreased brain infarction and improved functional recovery. CONCLUSION AND IMPLICATIONS SN exerts potent protective effects against ischaemic brain injury when administered before ischaemia or even after the injury. The inhibitory effects of SN on acid-sensing ion channel 1a and L-type calcium channels are involved in this neuroprotection.

Wu, Wen-Ning; Wu, Peng-Fei; Chen, Xiang-Long; Zhang, Zui; Gu, Jun; Yang, Yuan-Jian; Xiong, Qiu-Ju; Ni, Lan; Wang, Fang; Chen, Jian-Guo

2011-01-01

414

{alpha}-Lipoic acid prevents lipotoxic cardiomyopathy in acyl CoA-synthase transgenic mice  

SciTech Connect

{alpha}-Lipoic acid ({alpha}-LA) mimics the hypothalamic actions of leptin on food intake, energy expenditure, and activation of AMP-activated protein kinase (AMPK). To determine if, like leptin, {alpha}-LA protects against cardiac lipotoxicity, {alpha}-LA was fed to transgenic mice with cardiomyocyte-specific overexpression of the acyl CoA synthase (ACS) gene. Untreated ACS-transgenic mice died prematurely with increased triacylglycerol content and dilated cardiomyopathy, impaired systolic function and myofiber disorganization, apoptosis, and interstitial fibrosis on microscopy. In {alpha}-LA-treated ACS-transgenic mice heart size, echocardiogram and TG content were normal. Plasma TG fell 50%, hepatic-activated phospho-AMPK rose 6-fold, sterol regulatory element-binding protein-1c declined 50%, and peroxisome proliferator-activated receptor-{gamma} cofactor-1{alpha} mRNA rose 4-fold. Since food restriction did not prevent lipotoxicity, we conclude that {alpha}-LA treatment, like hyperleptinemia, protects the heart of ACS-transgenic mice from lipotoxicity.

Lee, Young [Gifford Laboratories, Touchstone Center for Diabetes Research, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Naseem, R. Haris [Division of Cardiology, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Park, Byung-Hyun [Gifford Laboratories, Touchstone Center for Diabetes Research, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Garry, Daniel J. [Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Richardson, James A. [Department of Pathology, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States); Schaffer, Jean E. [Department of Internal Medicine, Washington University School of Medicine, St. Louis, MO 63110 (United States); Unger, Roger H. [Gifford Laboratories, Touchstone Center for Diabetes Research, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States) and Department of Internal Medicine, University of Texas, Southwestern Medical Center, Dallas, TX 75390-8854 (United States) and Veterans Affairs Medical Center, Dallas, TX 75216 (United States)]. E-mail: roger.unger@utsouthwestern.edu

2006-05-26

415

Docosahexaenoic acid prevents trans-10, cis-12 conjugated linoleic acid-induced non-alcoholic fatty liver disease in mice by altering expression of hepatic genes regulating fatty acid synthesis and oxidation  

Technology Transfer Automated Retrieval System (TEKTRAN)

Background: Concomitant supplementation with docosahexaenoic acid (22:6 n-3; DHA) prevented t10, c12- conjugated linoleic acid (CLA)-induced non-alcoholic fatty liver disease (NAFLD) and insulin resistance. Effective dose of DHA and mechanisms involved are poorly understood. Methods: We examined abi...

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