• International Journal of Oral Biology
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• v.45 no.4
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• pp.162-168
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• 2020

Calcium is the most abundant stored mineral in the human body and is especially vital for bone health; thus, calcium deficiency can cause bone-related diseases, such as osteopenia and osteoporosis. However, a high concentration of serum calcium, which is commonly known as hypercalcemia, can also lead to weakened bones and, in severe cases, osteosarcoma. Therefore, it is necessary to maintain the concentration of calcium that is appropriate for bone biology. In the present study, we aimed to elucidate the effects of high concentration of calcium, approximately 2 folds the normal calcium level, on osteoblast differentiation. The CaCl2 treatment showed dose-dependent suppression of the alkaline phosphatase activity and mineralized nodule formation. Calcium showed cytotoxicity at an extremely high concentration, but a moderately high concentration of calcium that results in inhibitory effects to osteoblast differentiation showed no signs of cytotoxicity. We also confirmed that the CaCl2 treatment repressed the mRNA expression and protein abundance of various osteogenic genes and transcriptional factors. Considered together, these results indicate that a high concentration of calcium negatively regulates the osteoblast differentiation of C2C12 cells.

• Journal of Nutrition and Health
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• v.31 no.6
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• pp.1031-1038
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• 1998

The present study was carried out to investigate the effects of magnesium supplement levels and periods on calcium, magnesium, and phosphorus metabolism in male Sprague-Dawley rats given low protein and magnesium deficient diets for 2 weeks. Serum calcium content was significantly lower in the magnesium supplement group than in the magnesium-deficient group, but calcium excretion in urine and feces was significantly increased as magnesium level and period was increased. Increasing the dietary magnesium level and periods raised serum content and excretion of magnesium in urine k feces. Urinary excretion of phosphorus in two week group was significantly lower in the magnesium supplement group than in the magnesium-deficient group. fecal phosphorus excretion in supplement group (Mg 800mg/kg diet) was significantly higher than that of other group. (Korean J Nutrition 31(6) : 1031-1038, 1998)

• Korean Journal of Fisheries and Aquatic Sciences
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• v.36 no.3
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• pp.220-224
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• 2003

Effect of the ingestion of porphyran extracted from Porphyra yezoensis on calcium, magnesium and potassium contents in serum and tissue was investigated using hyperlipidemic and hypercholesterolemic rats. The contents of calcium magnesium and potassium in serum of rats fed porphyran for four weeks were higher than those of the control group. The contents of calcium and potassium were decreased with increasing a porphyran level while magnesium content was increased. Liver calcium contents in an $1\%$ porphyran group were significantly (p<0.05) higher than those in the control group, and magnesium contents in a $10\%$ porphyran group were higher than those in the control group. Kidney calcium and magnesium contents in rats fed porphyran were significantly (p<0.05) high compared with the control group. However, potassium content in kidney was Increased as a porphyran level was increased in diet. Spleen calcium and potassium contents were significantly lower in the porphyran groups than those in the control group. Rats fed the $5\%$ porphyran diet had higher magnesium content in spleen than any other diets. The results showed that diets supplemented with several porphyran levels had variable effects on the contents of calcium, magnesium and potassium in serum and tissue of hyperlipidemic rats.

• Journal of Nutrition and Health
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• v.39 no.8
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• pp.786-794
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• 2006

The purpose of this study was to establish an association between the consumption of ready-to-eat cereal (RTEC), milk, and calcium within the context of the most current population dietary practice in Korea. Inadequate calcium intake among Korean children and adults is one of the important public health concern. Milk is one of the best calcium sources because or its bioavailability, and RTEC is one or the foods commonly consumed with milk. The most recent Korean National Health and Nutrition Survey, 2001 dataset was used as the source of data for this research. Subjects excluding pregnant women, were categorized according to gender and age ($1{\sim}5,\;6{\sim}11,\;12{\sim}19,\;20{\sim}49,\;50+$ years) and then by consumption of RTEC and milk. SAS and SUDAAN were used for statistical analyses. Sample weighted means, standard errors, and population percentages were calculated, and multiple regression model with adjustment for covariates were used to determine the predictability of total daily calcium intake from inclusion of RTEC and milk compared to the meal without RTEC and milk. RTEC was consumed by 2.4% or Korean people. Average calcium intake was 17 times greater when RTEC was consumed with milk than when RTEC was consumed without milk. Respondents who consumed RTEC with milk had significantly higher mean daily calcium and other nutrient intakes than respondents who consumed neither. in the multiple regression analysis, milk consumption with or without RTEC predicted total daily calcium intake after adjusting for age, income, and alcohol consumption (p<0.0001). The percentage of respondents below the estimated average requirement (EAR) level for calcium was lower for RTEC consumers than for RTEC non-consumers in all age-gender groups, especially significant differences were in children aged $1{\sim}5$, boys and girls aged $12{\sim}19$, men aged $20{\sim}49$, and women older than 50 years of age. RTEC consumption was not associated with intake in excess of the tolerable upper intake level (UL) for calcium. In conclusion, RTEC consumption was positively associated with both milk and calcium intakes in all age and gender groups in Korean population.

• Journal of Nutrition and Health
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• v.13 no.3
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• pp.134-138
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• 1980

The present study was designed to investigate the effects of the level of calcium intake on it's apparent absorption rate in college women. Six college girls aged 19 to 20 were fed general dormitary meals containing approximately500mg of calcium for one week and thereafter, the experimental diets containing about 800mg of calcium were given for one week. Average values for calcium intake, fecal excretion of calcium, and apparent absorption rateof calcium in both periods were determined and these values for two periods were compared by using t-test. 1) Average intakes of calcium, protein, and fat of the subjects during the period of experimental diet were significantly higher than those of general diet period. 2) Higher consumption of three food groups; meat, poultry, and fishes, fruits and vegetables, and fats and oils were noted during experimental period. However, there was no significant difference in the consumption of cereals and milk groups during these two periods. 3) The apparent absorption rate of calcium during the experimental period was higher (64%) than the one for general diet period (56%). It was noteworthy that average calcium intakes was higher during the experimental diet period (785mg) than 536mg for general diet period while the fecal excretions of calcium in both periods were not significantly different.

• Journal of Plant Biology
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• v.38 no.3
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• pp.243-250
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• 1995

Involvement of calcium in signal transduction of salt stress was investigated in 1.7 M NaCl adapted Dunaliella salina, extremely halotolerant, unicellular green alga. When hyperosmotic (3.4 M NaCl) or Hypoosmotic (0.8 M NaCl) stress was treated, extracellular calcium was influxed in or intracellular calcium effluxed from D. salina, respectively, and these fluxes were proportional to the degree of stress. This might indicate indirectly that the change of calcium level occurred within the cells. In addition, the change of calcium flux was ahead of glycerol synthesis which has been known as the physiological response to salt stress. Osmoregulation was affected byextracellular calcium concentration, and increase of glycerol content as an osmoticum was inhibited about 50% by treatment of TFP and W-7 known as calmodulin specific inhibitors. Furthermore, in the case of the hyperosmotic stressed cells, the amount of 21 kD and 39 kD protein appeared to be calcium binding protein were increased. Among these, the 39 kD protein was detected only in the hyperosmotic stressed cells. The results obtained in the present work suggest that the possibility of calcium as a second messenger in the transduction of salt stress signal exists in the osmoregulation system of D. salina.

• Asian-Australasian Journal of Animal Sciences
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• v.5 no.2
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• pp.303-308
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• 1992

Three female sheep were daily administered a pyrophosphate analogue, disodium 1-hydroxyethylidene-1, 1-bisphosphonate (HEBP) at the level of 4 mg/kg body weight. HEBP largely suppressed bone resorption, which was indicated by the reduction in plasma free hydroxyproline concentration and in calcium mobilization rate during the intravenous infusion of disodium ethylenediaminetetraacetate (EDTA). Contrary to the suppression of bone resorption, plasma total-calcium, magnesium and phosphorus concentrations were not changed by HEBP administration. These results suggest that bone mineral crystals play a meaningless role on calcium, magnesium and phosphorus homeostasis in ruminants if they are fed adequate amounts of these minerals. Plasma magnesium and phosphorus concentrations were not significantly changed after feeding. However, plasma total-calcium was decreased after feeding in both periods and the reduction seemed to be remarkable in the HEBP-treated period. Infusion of EDTA more remarkably reduced plasma ionized calcium concentration in the HEBP-treated that in the untreated period and the recovery of ionized calcium was retarded by HEBP administration. These results suggest that calcium release from bone is necessary for maintenance of plasma calcium when animals rapidly lose calcium.

• Journal of the Korean Society of Tobacco Science
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• v.11 no.1
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• pp.3-9
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• 1989

Field experiment was conducted to find out the cause of calcium deficiency of burley tobacco (Nicotiana tabacum L.), Liming materials and application rate were CaSO4 : Ca 35kg/10a, CaCO3 : 35kg/10a and agricultural lime : Ca 142kg/10a. The breakdown in tissues at tips and margins of upper leaves was developed at maximum growth stage. If complete breakdown and death does not occur and growth takes place later, giving the leaf a scalloped appearance. Upper leaves contained lower calcium content than other leaves. The stem and midvein of calcium deficient plants contained lower calcium and calcium minus oxalic acid, but higher oxalic acid contents than those of normal plant. Fresh leaves of limed plot contained higher calcium and oxalic acid, but not significant increment of calcium minus oxalic acid than those of unlimed plot. Since calcium oxalate is insoluble, it could precipitate within the culls if the calcium and oxalic acid are accessible to each other. It suggest that high level of oxalic acid in stem and midvein could be interfering with translocation of calcium to upper leaves.

• Journal of the Korean Society of Food Science and Nutrition
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• v.25 no.6
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• pp.1006-1015
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• 1996

This study was carried out to investigate the effects of dietary calcium-salt, estrogen-treatment, and estrogen/calcium treatment on calcium, phosphorus and nitrogen metabolism. Female Sprague-Dawley rats with a body weight of 250~280g were underwent ovariectomy or sham-operation. The ovariectomized rats were divided into 9 different experimental groups including the saline-treated group, the estrogen-treated group, the high calcium salt-treated group, and the estrogen/calcium treated groups and fed for 6 weeks. Each group daily intake and excretion of calcium, phosphorus and nitrogen were measured and apparent digestibility and balance were also studied. The results were as follows: The excretion level of winn calcium was significantly higher the ovariectomized rats than the sham-operation group(p<0.01) and reduced with estrogen treatment but this difference was not statistically significant. Fecal loss of calcium was higher the ovariectomized rats than the sham-operation group(p<0.001). When the estrogen was treated, fecal loss was decreased and then apparent digestibility of calcium was increased. Calcium balance was significantly higher the high calcium treated groups than the control diet groups. The excretion level of urinary Phosphorus was higher the ovariectomized rats than sham-operation group, while these showed to be decreased in the calcium salt, the estrogen and the estrogen/calcium treated groups(p<0.01). Fecal loss of phosphrous was higher in the ovariectomized rats. When the estrogen was treated, the fecal loss was decreased in the avariectomized rat than that of other groups. The excretion level of urinary nitrogen was higher the ovariectomized rats than the sham-operation, while these showed to be decreased in the estrogen, the estrogen/calcium, and the estrogen gradually reduction/calcium intensification. Fecal loss of nitrogen was decreased in tile estrogen treated group. The results in this study showed that high calcium, estrogen/calcium and estrogen gradually reduction/calcium intensification in the ovariectomized rats enhanced calcium balance compared to the ovariectomized rats without calcium treatment, but little effects on the phosphorus and nitrogen balance.

• Journal of the East Asian Society of Dietary Life
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• v.6 no.2
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• pp.143-151
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• 1996

This study was performed to investigate the effect of dietary dried anchovy and non-fat dried milk on serum and femur Ten months old female rats were divieded into 6 groups(ST, A-middle, A-high, M-middle, M-high, A+M), and fed the diet containing different level of food calcium for 8 weeks. The results obtained were summerized as follow: 1. The rats' weight gain were not significantly different from the fed groups, but food intake were significantly higher or lower level in the group of A-high than the other groups. 2. Serum calcium concentration was significantly increased in the A-middle group, the M-high group were significantly decreased. Serum phosphorous contents of M-high group were increased significantly higher than ST group. The serum magnesium contents were increased significantly higher than in the A-middle group. Serum iron contents of other experimental groups were significantly higher than ST group. All experimental groups were significantly lower copper contents in serum than ST group. 3. The more rats took dried anchovy and non-fat dried milk, the longer the length of femur. But this trend is not statistically difference. In the breaking force of left femur, most of all experimental group were stronger than ST group. 4. The calcium, phosphorous contents of ash, dry, wet weight of right femur in A+M group were higher than any other groups.