• Journal of Nutrition and Health
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• v.12 no.1
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• pp.17-22
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• 1979

This study was designed to investigate calcium intake, the ratio of Ca intake versus R.D.A. (Recommended Dietary Allowance) for Ca, apparent Ca absorption rate, and Ca sources of food among school children in Korea. One hundred school children aged from 6 to 12 years were engaged in this study; 33 subjects were from farming village neal Seoul, and 67 children from big cities. Two days of food consumption records and feces collections of the subjects had been done from April 1978 to June 1978. The following observations were made in the present study; 1) Average Ca intake of total subjects was $457{\pm}214mg$ which is only 76% of R.D.A. for Ca. Calcium intakes for farming village children was higher than that of the subjects from big cities (p<0.05). 2) Survey on the food sources of Ca revealed that the amount of Ca taken from cereals averaged 120 mg (22.3% of total Ca intake), 111 mg (24.3%) from fruits and vegetables, 176 mg (38.5%) from meats, poultry, fishes and eggs, and only 68 mg (14.9%) was supplied by milk and milk products. From the data collected, following observations were made; a) No significant difference in Ca intake from cereals was found between village children and the ones from big cities. b) Average Ca intake from fruits and vegetables of city children was significantly higher than that of village children (p<0.005) with the values for 133 mg for the former and 64 mg for the latter. c) For the group of meats, poultry, fishes and eggs, significantly higher intake was found in village subjects than city children (p<0.0005) with the values of 340 mg and 95 mg, respectively. d) Contrarily, Ca intake from milk and milk products was significantly (p<0.0005) much higher in the city children (98 mg) than village ones (7 mg). 3) Apparent Ca absorption rate of total subjects was 51%; 44% for village children and 54% for city children. Ca absorption rate tends to be higher in the city subjects but no significant difference was noted.

• Journal of Nutrition and Health
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• v.43 no.4
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• pp.351-356
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• 2010

This study was done to evaluate the effect of Ca source using fish (Tilapia mossambica) scales on the bone metabolism. Male Sprague-Dawley rats, 4 weeks of age, were fed low-calcium diet (0.15% Ca) for 2 weeks. The rats on the low-calcium diet were further assigned to one of following three groups for an additional 4 weeks: 1) Ca-depletion group (LoCa) given 0.15% Ca diet ($CaCO_3$), 2) Ca-repletion group (AdCa) given 0.5% Ca diet ($CaCO_3$), 3) Ca-repletion diet (AdFa) received 0.5% Ca diet (Ca source from Tilapia mossambica scales). Serum parathyroid (PTH) and calcitonin showed no differences among experimental groups. Whereas LoCa group elevated the turnover markers, serum ALP and osteocalcin, and urinary deoxypyridinoline (DPD), AdCa and AdFa groups reduced their values. Elevation in the femoral weight, ash and Ca contents was observed in AdCa and AdFa groups. Bone mineral density was increased in AdCa and AdFa groups by 25-26% compared with LoCa group. These data demonstrate that Ca repletion with either Ca source from Tilapia mossambica scales or $CaCO_3$ is similarly effective in the improvement of bone turnover markers and BMD, suggesting the usefulness of Tilapia mossambica scales in the prevention of bone loss compared with $CaCO_3$.

• Clinical and Experimental Reproductive Medicine
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• v.27 no.3
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• pp.275-282
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• 2000

Objective: This study was to determine the effect of different concentration of calcium III medium on the preimplantational development of zygotes and early 2 cell embryos. Methods: Female mice of ICR strain ($5{\sim}8$ weeks old) were superovulated and mated with fertile males. Zygotes or early 2-cell embryos were collected by flushing the oviducts $31{\sim}32$ hours after hCG injection. The embryos were cultured in various concentrations of $Ca^{2+}$ in medium or with EDTA, EGTA and $Ni^{2+}$. Result and Conclusion: Treatment of high concentraion of $Ca^{2+}$ (3.42 mM $(2X){\sim}17.l$ mM (10X)) in medium didn't develop well compared to the control. Low concentrations of $Ca^{2+}$ (0.214mM $(1/8X){\sim}0.855$ mM (1/2X) were deterimental to development beyond 2-cell stage. EDTA, $Ca^{2+}$ chelating agent was treated with ranged concentrations of EDTA (0.014 $mM{\sim}0.107$ mM) to medium contaning 1.71 mM $Ca^{2+}$ showed beneficial effect to development to blastocyst compared to the control. EGTA, extracellular $Ca^{2+}$ chelator, was treated with ranged concentrations of EGTA ($0.014{\sim}0.107$ mM) to the medium contaning 1.71 mM $Ca^{2+}$. There is no significant difference with the control. $Ni^{2+}$ (50 ${\mu}M$), T-type $Ca^{2+}$-channel blocker was treated to medium contaning low concentration of $Ca^{2+}$. It overcame 2-cell block significantly. Rate of degenerated embryos decreased and developmental rate to morula and blastocyst increased more than low $Ca^{2+}$ concentration alone. Further studies are needed for the overcoming effect of 2-cell block by $Ni^{2+}$.

• Journal of the Korean Ceramic Society
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• v.29 no.1
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• pp.74-82
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• 1992

Ultra-fine calcium phosphate powders were synthesized by the reaction of Ca(OH)2 suspension with various phosphoric aqueous solutions such as (NH4)2HPO4, H4P2O7 and H3PO4, and the characterization of powders was examined for each synthetic condition. When (NH4)2HPO4 and H3PO4 were used, hydroxyapatite powders with poor crystallinity were obtained. In the case of H4P2O7, amorphous calcium phosphate was obtained up to 0.3 mol/ι Ca(OH)2 suspension, but above the concentration, poor crystalline hydroxyapatite was produced. Crystalline phases of powders heat-treated at 80$0^{\circ}C$ were hydroxyapatite, $\beta$-tricalcium phosphate and $\beta$-tricalcium phosphate for the case of (NH4)2HPO4, H4P2O7 and H3PO4, respectively. SEM observation revealed that the shapes of synthesized powders were vigorously agglomerated spherical with the size below 100 nm, but TEM observation revealed that primary shapes of particles were rod for (NH4)2HPO4 and H3PO4 and were sphere for H4P2O7. There was no dependence of the concentration of Ca(OH)2 suspension. In the case that reaction temperature and pH of the suspension were raised, the inclination to the hydroxyapatite were remarkable. The amorphous calcium phosphate synthesized in this experiment contained water about 20% , and was crystallized to $\beta$-tricalcium phosphate at 69$0^{\circ}C$.

• Horticultural Science & Technology
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• v.33 no.4
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• pp.525-534
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• 2015

The effects of aqueous calcium oxide (CaO) treatment on the quality characteristics and shelf life of mulberry (Morus alba L.) were investigated. Mulberry fruits were immersed in 0, 0.5, 1, and $2g{\cdot}L^{-1}$ CaO solutions for 0, 1, 3, 6, and 12 min. Mulberries were then rinsed with potable tap water for 1 min and stored at $-1^{\circ}C$ for 14 days. CaO treatment was effective at promoting the retention of titratable acid, pH, and ascorbic acid as well as total flavonoid contents. CaO concentration and treatment time were significant factors affecting the sensory qualities of the fruits, including off-odor, flavor, and texture. For shelf life determinations, the total bacterial count was reduced by CaO treatment so that the samples treated with $1g{\cdot}L^{-1}$ CaO for 12 min had bacterial levels at 14 days comparable to those of the control at 4 day, and no coliform group was detected after CaO treatment. These results indicate that calcium oxide treatment is a promising approach for the preservation of mulberry fruit.

• Journal of Korean Society for Atmospheric Environment
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• v.29 no.3
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• pp.325-337
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• 2013

The size-fractionated aerosol samples have been collected at Gosan Site of Jeju Island during the spring season of 2010, in order to examine the chemical composition characteristics of the Asian Dust and Non-Asian Dust particles. The concentrations of ${HCO_3}^-$, Al, and nss-$Ca^{2+}$ in $PM_{10}$ had tremendously increased during the heavy Asian Dust (March 20, 2010). The concentration ratios of Asian Dust to Non-Asian Dust for the soil species (nss-$Ca^{2+}$, ${HCO_3}^-$, Al, Fe, Ti, Mn) were 12.2~30.7, meanwhile those for the anthropogenic species (nss-${SO_4}^{2-}$, ${NH_4}^+$, ${NO_3}^-$, $K^+$, Zn, Pb, and Cu) were 2.9~7.8. During the heavy Asian Dust event, the concentration increase of ${NO_3}^-$ in $PM_{2.5}$ were much more apparent than those of nss-${SO_4}^{2-}$ and ${NH_4}^+$, and the soil species (nss-$Ca^{2+}$ and ${HCO_3}^-$) showed much higher concentration increase. The neutralization factor of $NH_3$ was higher than that of $CaCO_3$. However, the neutralization factor of $CaCO_3$ in $PM_{10}$ was exceptionally high during the heavy Asian Dust, showing the evidence of heavy migration of soil particles. From the study for size fractionated particles, it was found that nss-${SO_4}^{2-}$ and ${NH_4}^+$ were mostly distributed in fine particle mode, on the other hand, ${NO_3}^-$ existed evenly in both fine and coarse particle modes, and the soil species (nss-$Ca^{2+}$, Al, Fe, etc.) were mainly in the latter mode. During the heavy Asian Dust, in particular, the concentrations of ${NH_4}^+$, nss-${SO_4}^{2-}$, $K^+$, Zn, and Pb had increased in coarse particle mode as well.

• The Korean Journal of Physiology
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• v.21 no.2
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• pp.191-200
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• 1987

The activation mechanism of the sustained contractions induced by norepinephrine and K-depolarization was studied in renal vascular muscle. Helical strips of arterial muscle were prepared from rabbit renal arteries. All experiments were performed in Tris-buffered Tyrode solution which was aerated with 100% $O_2$ and kept at $35^{\circ}C$. Renal arterial muscles developed a contracture rapidly when exposed to a 40 mM K-Tyrode solution. In the absence of external $Ca^{2+}$, however, no K-contracture appeared. The contracture induced by K-depolarization was abolished by the treatment with $Ca^{2+}-antagonist\;(verapamil)$ or lanthanum $(La^{3+})$. From these results, it is obvious that K-contracture of renal arterial strip required $Ca^{2+}$ in the medium and this contracture was developed by the increased $Ca^{2+}-influx$ due to K-depolarization. Noradrenaline (5 mg/l) induced also a similar sustained contraction rapidly in all strips. Even on the K-contracture and in $Ca^{2+}-free$ Tyrode solution and also in the Tyrode solution pretreated with verapamil or $La^{3+}$, noradrenaline produced a contraction. However, the contraction in $Ca^{2+}-free$ Tyrode solution was not sustained and decreased gradually. The amplitude of noradrenaline-induced contracture was dependent on external $Ca^{2+}$; The contracture increased dose-dependently, but over 3 mM $Ca^{2+}$, decreased. The results of this experiment suggest that K-contracture was developed by an increased $Ca^{2+}-influx$ due to membrane depolarization, while noradrenaline-induced contracture was developed by both transmembrane $Ca^{2+}-influx$ and the mobilizaiton of cellular $Ca^{2+}$

• Journal of the Korean Society of Food Science and Nutrition
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• v.3 no.1
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• pp.83-95
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• 1974

This experiment was initiated to determine the effective components of garlic during the growth stages and to regulate the contents artificially. The following results were obtained : 1. Alliin content was increased during its growth and showed drastic increase at maturing stage. 2. The kinds of free amino acids detected during growth stages were 15 for leaf growth, 14 for bulbing and 18 for maturing stage. The total content of free amino acids was high. est at maturing stage. 3. The optimum conditions for the maximum amounts of alliin and free amino acid determined by the binary interaction of Systematic Variations Method were 40% $NO_3^{-1}+60%\;SO_4^{-2}$, 62% $NO_3^{-1}+38%\;PO_4^{-3}$, 42% $K^{+1}+58%\;Ca^{+2}$ and 56% $K^{+1}+44%\;Mg^{+2}$ for alliin, and 72% $NO_3^{-1}+28%\;SO_4^{-2}$, 49% $NO_3^{-1}+51%\;SO_4^{-2}$, 45% $K^++55Ca^{+2}$ and 66% $K^{+1}+34%\;Mg^{+2}$ for free amino acid. 4. Ideal curve for alliin and free amino acid was attained by applying the binary interaction of Systematic Variations Method and it was possible to approach the optimum ionic proportion from the optimum contents on this curve.

• The Korean Journal of Physiology and Pharmacology
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• v.4 no.6
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• pp.445-453
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• 2000

The present investigation tested the hypothesis that the activation of protein kinase G (PKG) leads to a phosphorylation of $Ca^{2+}-activated$ potassium channel $(K_{Ca}\;channel)$ and is involved in the activation of $K_{Ca}$ channel activity in cerebral arterial smooth muscle cells of the rabbit. Single-channel currents were recorded in cell-attached and inside-out patch configurations of patch-clamp techniques. Both molsidomine derivative 3-morpholinosydnonimine-N-ethylcarbamide $(SIN-1,\;50\;{\mu}M)$ and 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate $(8-pCPT-cGMP,\;100\;{\mu}M),$ a membrane-permeable analogue of cGMP, increased the $K_{Ca}$ channel activity in the cell-attached patch configuration, and the effect was removed upon washout of the drugs. In inside-out patches, single-channel current amplitude was not changed by SIN-1 and 8-pCPT-cGMP. Application of ATP $(100\;{\mu}M),$ cGMP $(100\;{\mu}M),$ ATP+cGMP $(100\;{\mu}M\;each),$ PKG $(5\;U/{\mu}l),$ ATP $(100\;{\mu}M)+PKG\;(5\;U/{\mu}l),$ or cGMP $(100\;{\mu}M)+PKG\;(5\;U/{\mu}l)$ did not increase the channel activity. ATP $(100\;{\mu}M)+cGMP\;(100\;{\mu}M)+PKG\;(5\;U/{\mu}l)$ added directly to the intracellular phase of inside-out patches increased the channel activity with no changes in the conductance. The heat-inactivated PKG had no effect on the channel activity, and the effect of PKG was inhibited by 8-(4-Chlorophenylthio)-guanosine-3',5'-cyclic monophosphate, Rp-isomer $(Rp-pCPT-cGMP,\;100\;{\mu}M),$ a potent inhibitor of PKG or protein phosphatase 2A (PP2A, 1 U/ml). In the presence of okadaic acid (OA, 5 nM), PP2A had no effect on the channel activity. The $K_{Ca}$ channel activity spontaneously decayed to the control level upon washout of ATP, cGMP and PKG, and this was prevented by OA (5 nM) in the medium. These results suggest that the PKG-mediated phosphorylations of $K_{Ca}$ channels, or some associated proteins in the membrane patch increase the activity of the $K_{Ca}$ channel, and the activation may be associated with the vasodilating action.

• The Korean Journal of Physiology and Pharmacology
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• v.8 no.4
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• pp.227-235
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• 2004

The aim of the present study was to examine the effect of leptin on CA release from the isolated perfused model of the rat adrenal gland, and to establish its mechanism of action. Leptin $(1{\sim}100\;ng/ml)$, when perfused into an adrenal vein of the rat adrenal gland for 60 min, enhanced a dose-dependently the secretory responses of CA evoked by ACh $(5.32{\times}10^{-3}\;M)$, DMPP $(10^{-4}\;M)$ and McN-A-343 $(10^{-4}\;M)$, although it alone has weak effect on CA secretion. However, it did not affect the CA secretion evoked by excess $K^+\;(5.6{\times}10^{-2}\;M)$. Leptin alone produced a weak secretory response of the CA. Moreover, leptin (10 ng/ml) in to an adrenal vein for 60 min also augmented the CA release evoked by BAY-K-8644, an activator of the dihydropyridine L-type $Ca^{2+}$ channels, and cyclopiazonic acid, an inhibitor of cytoplasmic $Ca^{2+}$ ATPase. However, in the presence of U0126 $(1\;{\mu}M)$, an inhibitor of mitogen-activated protein kinase (MAPK), leptin no longer enhanced the CA secretion evoked by ACh and DMPP. Furthermore, in the presence of anti-leptin (10 ng/ml), an antagonist of Ob receptor, leptin (10 ng/ml) also no longer potentiated the CA secretory responses evoked by DMPP and Bay-K-8644. Collectively, these experimental results suggest that leptin enhances the CA secretion from the rat adrenal medulla evoked by cholinergic stimulation (both nicotininc and muscarinic receptors), but does not that by membrane depolarization. It seems that this enhanced effect of leptin may be mediated by activation of U0126-sensitive MAPK through the leptin receptors, which is probably relevant to the activation of the dihydropyridine L-type $Ca^{2+}$ channels located on the rat adrenomedullary chromaffin cells.