• Journal of Nutrition and Health
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• v.34 no.4
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• pp.433-439
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• 2001

Intakes and excretions of calcium and phosphorus were determined for 8 female adolescents(aged 16.3$\pm$0.5y; body mass index 20.4$\pm$1.3kg/$m^2$; body fat 33.3$\pm$2.5%; bone mineral density of lumbar spine in L2-L4; 0.96$\pm$0.08g/$\textrm{cm}^2$) when they consumed diets basal and high in calcium for 6 days each. All subjects consumed a basal Ca diet containing 800mg, Korean RDA level of the subjects, and a high Ca diet containing 1200mg, RDA plus 2 SDs of calcium intake. The diets provided 58% of energy intake as carbohydrate, 25% as fat, and 17% as protein. Food, urine, and fecal composites were collected during the last 3 days of each feeding period. Fecal excretion of calcium was significantly greater on the high Ca than on the basal Ca diet. Hence, apparent absorption rate was significantly lowered from 40.9% on the basal Ca diet to 33.1% on the high Ca diet. There was no significant difference in calcium retention between the two diet periods but it tended to be greater on the high Ca diet. However, excretions and retention of phosphorus did not show any significant difference even though intake was significantly increased from 1,253mg on the basal Ca diet to 1,583mg on the high Ca diet. The results indicate that higher calcium intake than the Korean RDA level is recommended for adolescents to meet peak bone mineral accretion and attain a desirable level of calcium retention. (Korean J Nutrition 34(4) : 433~439, 2001)

• Journal of Nutrition and Health
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• v.26 no.2
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• pp.154-154
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• 1993

A factorial experiment was conducted to determine the influence of phytate(0 or 10g/kg diet) and calcium (Ca)(3 or 10g/kg diet) intakes on Ca, P and Zn metabolism by growing female rats. Food intake and weight were similar for the all groups, however, phytate ingestion for six weeks depressed femur growth. The low Ca plus phytate group showed the lowest Ca content of total femur and this was related to a significant decrease of Ca retention. Phytate intake depressed zinc(Zn) absorption in the first metabolic collection. This inhibitory effect of phytate on Zn absorption was improved in the low Ca plus phytate group after several weeks. Impared Zn absorption however remained in the high Ca plus phytate group which was reflected in the lowest Zn content of femur, phytate intake with high Ca also depressed phosphorous(P) absorption and serum and urinary P. These adverse effects of phytate on Zn and P absorption when the dietary Ca was high could explain reduced femur weight despite the highest concentration of femur Ca(mg/g ash) in this group. Results suggest that phytate can adversely affect not only Ca metabolism but Zn and P utilization. Thus, for the normal bone growth when phytate intake is high, the ingesion of Ca, P, Zn and other minerals should be enhanced.

• Journal of Nutrition and Health
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• v.33 no.4
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• pp.403-410
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• 2000

The effects of dietary Ca and Na levels on lipid metabolism in hyper lipidemic/hypercholesterolemic rats were examined. In Expt. 1, normal rats were divided into six groups and fed high fat(15%, w/w)/cholesterol(1%, w/w) diet containing two levels of Na, low (0.05) or high(1.5%) and three levels of Ca, low(0.1%), normal (0.5%), or high(1.5%) for 8 weeks. In Expt. 2, hyperlipidemia / hypercholesterolemia rats were induced by feeding high fat / cholesterol diet for 4 weeks. They were divided into four groups and fed the high fat / cholesterol diet, containing two levels of Na, low or high and two levels of Ca, low or high for 4 weeks. In Expt. 1, total lipid and total cholesterol contents in serum and liver were significantly lower in rats fed high Ca diet than in rats fed normal or low Ca diet regardless of dietary Na levels. Serum TG was the highest in rats fed low Ca and low Na diet. In Expt. 2, Serum total lipid, TG, and total cholesterol levels decreased by 24, 35, 26% respectively in rats fed high Ca diet regardless of dietary Na levels. Serum total lipid level tended to increased in rats fed low Na diet. The total lipid and TG contents in liver slightly decreased in rats fed high Ca diet. Another observation was that high Ca intake significantly faciliated the fecal lipid and cholesterol excretion regardless of dietary Na levels. There results suggest that the hypolipidemidc/hypocholesterolemic effects of high Ca diet could be partly due to increase in lipid and cholesterol excretion and these effects may be independent of dietary Na levels.

• Journal of Nutrition and Health
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• v.31 no.4
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• pp.716-728
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• 1998

To investigate the effect of dietary Ca levels on metabolic changes of Ca and skeleton in postmenopausal women, 10-month-old ovariectomized female rats were compared with 2 month old rats. The rats were fed either 0.2% or 1.2% Ca diets for 16 weeks. Food intake and weight gain as higher in rats fed high Ca diets and in ovariectomized rats. Apparent Ca absorption as higher, and Ca balance was lower in the low Ca groups. Vertebrae density was higher in old rats or those fed a high Ca diets. The old rats and ovariectomized rats showed decreased bone formation, increased bone resorption and kidney function deterioration resulting in increased urinary Ca excretion. Contradictory to the above observation, old rats and ovariectomized rats still showed higher bone mass and bone ash content. Therefore aging was not fully onging in 10-month-old rats. Bone weights, mineral contents, and mineral/wt ratio were lower in ovariectomized rats. Dietary Ca level did not affect urinary Ca excretion, urinary protein excretion, GFR, serum alkaline phosphatase, or urinary hydroxyporline excretion. This means that dietary Ca level did not influence kidney function or bone turnover. However Ca content and the ash content of femur, 4th vertebra, and scapula were increased in high Ca groups. Therefore, it is considered that decreased bone formation and accelerated bone resorption may account for the increased osteoporotic risk in women in menopause after middle age. However, Ca metabolism can be improved and bone components can be maintained if Ca is supplemented.

• Journal of the Korean Society of Manufacturing Process Engineers
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• v.10 no.5
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• pp.31-37
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• 2011

For the domestic glasses industry to procure competitiveness in the world CA(Cellulose Acetate) frame of spectacles market, CNC machining system for CA frame including high-value added CA cutting technologies should be developed with new materials for the rim based on Cellulose and sheet manufacturing base. The spindle system of glasses frame equipment that is the core to the quality of CA frame is the key technologies to realize high-speed, high-precision so its importance is remarkably emerging. In the study, at the structural design of the high spindle system of the private equipment for CA glasses frame embedded a motor of 40,000rpm, the stability of design was analyzed and investigated through selecting lubrication structure and thermal characteristics of the spindle system.

• Journal of Nutrition and Health
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• v.33 no.2
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• pp.147-157
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• 2000

This study examined the effects of excess intake of calcium (Ca) and iron (Fe) supplement on bone loss, nephrocalcinosis and renal function in osteoporotic model rats. Seven-week-old female rats were first fed a Ca-deficient diet for four weeks after ovariectomy operation, and then one of nine experimental diets for additional eight weeks, containing three levels of Ca, normal (0.5%) or high (1.5%) or excess (2.5%) and three levels of Fe, normal (35ppm) or high (210ppm) or excess (350ppm). The osteoporotic model rats showed a remarkable increase in body weight, serum alkaline phosphatase (ALP) and decrease in breaking force, Ca, P, Mg contents of femur. Serum Ca concentration was not significantly affected by dietary Ca and Fe levles. Liver Ca content increased in rats fed a high-and excess-Ca diet. Kidney Ca content and microscopic Ca deposition remarkably increased in osteoporotic model rats compared to control group, and showed a tendency to decrease in rats fed a excess-Ca diet. Breaking force of femur increased with increasing dietary Ca levels, but Ca, P contents of femur and serum ALP were not significantly affected by dietary Ca and Fe levels. Serum total protein decreased in rats fed a excess-Ca diet, BUN increased in rats fed a excess-Ca diet, while serum uric acid and creatinine were not significantly affected by dietary Ca levels. Urinary creatinine, GFR increased in rats fed a high-and excess-Ca, diet, and GFR was highest in rats fed a excess-Ca/excess-Fe diet. These results suggest that excess intake of Ca may increase breaking force of femur, but not increase mineral contents of femur, and decrease kidney function. Furthermore, excess intake of Fe and Ca concurrently may aggravate kidney function leading to potential health problems in ovariectomized osteoporotic model rats.

• Journal of Nutrition and Health
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• v.34 no.4
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• pp.409-416
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• 2001

In order to evaluate the effect of habitual Na and Ca intake on blood pressure regulation, we measured the habitual dietary intakes of Na and Ca, urinary excretion of Ca, Na and K, and plasma level of renin activity, aldosterone, and indices of Ca metabolism in 27 untreated hypertensive women and 30 age-matched normal women on a free diet. Hypertensive and total subjects were divided into four groups according to habitual dietary intakes of Na and Ca as low Na-low Ca(LNLC), low Na-high Ca(LNHC), high Na-low Ca(HNLC), and high Na-high Ca(HNHC). HNLC hypertensive group showed the lowest level of plasma renin activity, 25-(OH) Vit D$_3$, calcitonin and serum total Ca, and presented the highest level of PTH and urinary excretions of Na/K and Ca/Cr. There were no significant difference in plasma level of aldosterone and urinary excretion of Na and K among four hypertensive groups. When all subjects were divided into four groups according to the same method, HNLC group showed the highest level of blood pressure with no statistical significance and the lowest level of calcitonin and total serum Ca. The above results indicated that renin-aldosterone system and Ca regulating hormone has a mutual relationship in hypertension. Na and Ca may interact each other, rather than affecting independently blood pressure control. As a result, considering the fact that daily balance of Na and Ca intakes affects Na and Ca regulating hormones and urinary excretion of Na and Ca, it may be involved in blood pressure control. These results suggest that maintaining an adequate intake of Ca with less intake of Na may prevent from the risk of hypertension. (Korean J Nutrition 34(4) : 409~416, 2001)

• Journal of Nutrition and Health
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• v.28 no.5
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• pp.415-425
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• 1995

This study was performed to investigate the effect of dietary protein level on the metabolic changes of Ca and skeletons in postmenopausal women, using ovariecotomized rats as an animal model. The female rats of 200∼250g were fed either 8%(L) or 50%(H) casein diet for 15 weeks(1st experiment). At 15th week, the rats of each diet group were undergone ovariectomy or sham-operation and they were continued to feed the same experimantal diet for 9 more months(2nd experiment). Ca metabolism, kidney function and bone composition were determined at the end of 1st experiment, 3rd and 9th month of 2nd experiment. After 1st experiment, high protein group showed higher urinary Ca and protein excretion, however, there was no difference in GFR and urinary hydroxyproline excretion. The weights, ash and Ca content of femur, scapular and vertebra tended to be higher in high protein groups which tells that high protein promoted skeletal growth. In 2nd experiment, high protein group showed higher urinary Ca and protein excretion and lower Ca absorption and balance. GFR was not affected by dietary protein and ovariectomy but increased with time, as well as kidney weight which shows the continuous development of kidney at this age of 15 month in rats. There were no difference in urinary hydroxyproline, serum ALP, and PTH among experimental groups. The weights of femur, scapular, 4th vertebra increased with time, showing the skeleton continues to grow at this age in rats. However, Ca contents, Ca/wt, Ca/ash were decreased with time and tended to be lower in high protein group especially in femur. In conclusion, prolonged feeding of high protein diet deteriorated Ca metabolism and induced bone loss as time after menopause is extended.

• The Korean Journal of Physiology
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• v.20 no.2
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• pp.257-270
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• 1986

It has been reported that the luteal function may be regulated by the intracellular calcium in luteal cells (Higuchi et al, 1976; Dorflinger et at, 1984; Gore and Behrman, 1984) which is adjusted partially by $Ca^{++}-ATPase$ activities in luteal cell membranes (Verma and Pennistion, 1981). However, the physicochemical and kinetic properties of $Ca^{++}-ATPase$ in luteal membranes were not fully characterized. This study was, therefore, undertaken to partially characterize the physicochemical and kinetic properties of $Ca^{++}-ATPase$ system in luteal membranes and microsomal fractions, known as an one of the major $Ca^{++}$ storge sites (Moore and Pastan, 1978), from the highly luteinized ovary Highly luteinized ovaries were obtained from PMSG-hCG injected immautre female rats. Light membrane and heavy membrane fractions and microsomal fractions were prepared by the differential and discontinuous sucrose density gradient centrifugation method desribed by Bramley and Ryan (1980). Light membrane and heavy membrane fractions and microsomal fractions from highly luteinized ovaries are composed of the two different kinds of $Ca^{++}-ATPase$ system. One is the high affinity $Ca^{++}-ATPase$ which is activated in low $Ca^{++}$ concentration (Km, 10-30 nM), the other is low affinity $Ca^{++}-ATPase$ activated in higher $Ca^{++}$ concentration $(K_{1/2},\;40\;{\mu}M)$. At certain $Ca^{++}$ concentrations, activities of high and low affinity $Ca^{++}-ATPase$ are the highest in light membrane fractions and are the lowest in microsomal fractions. It appeares that high affinity $Ca^{++}-ATPase$ system have 2 binding sites for ATP (Hill's coefficient; around 2 in all membrane fractions measured) and the positive cooperativity of ATP bindings obviously existed in each membrane fractions. The optimum pH for high affinity $Ca^{++}-ATPase$ activation is around S in all membrane fractions measured. The lipid phase transition temperature measured by Arrhenius plots of high affinity $Ca^{++}-ATPase$ activity is around $25^{\circ}C$. The activation energies of high affinity $Ca^{++}-ATPase$ below the transition temperature are similar in each membrane fractions, but at the above transition temperature, it is the hightest in heavy membrane fractions and the lowest in microsomal fractions. According to the above results, it is suggested that intracellular $Ca^{++}$ level, which may regulate the luteal function, may be adjusted primarily by the high affinity $Ca^{++}-ATPase$ system activated in intracellular $Ca^{++}$ concentration range $(below\;0.1\;{\mu}M)$.

• Asian-Australasian Journal of Animal Sciences
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• v.12 no.1
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• pp.49-55
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• 1999

The effect of fat supplementation of high calcium (Ca) diets on the performance, intestinal pH, body composition and size and weight of organs in growing chickens were investigated in two experiments. Growing chickens tolerated a high dietary level of Ca (22.5 vs 12.1 g/kg) in the presence of 6.3 g/kg of available phosphorus without any significant effect on performance. Intestinal pH was significantly increased by the addition of excess Ca and fat which probably created the right pH for the formation of insoluble Ca soaps. Excess dietary Ca increased carcass linoleic acid concentration at the expense of palmitic and stearic acid contents, whilst the addition of sunflower oil (80 g/kg diet) to the diet increased carcass linoleic acid concentration at the expense of palmitic acid content of the carcass. Intestinal and visceral organ size and weight were not influenced by excess Ca or fat. However, there was a non significant increase in the intestinal dry weight per unit of length caused by excess dietary Ca. It was concluded that excess dietary Ca of 22.5 g/kg did not significantly influence the performance of meat chickens. However, excess Ca increased intestinal pH and altered carcass fatty acid composition. Fat supplementation did not alter intestinal pH with high Ca diets. Excess dietary fat altered carcass fatty acid composition and reduced protein content. Intestinal and visceral organ size and weights were not influenced by excess dietary levels of Ca of fat.