• 대한약리학회지
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• 제32권2호
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• pp.221-231
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• 1996

The properties of cytosolic $Ca^{2+}$ level$([Ca^{2+}]_i)$ movement of high KCl, carbachol and oxytocin were examined with myometrium isolated from non-pregnant rat(estrus cycle). High concentration of KCl$({\leq}23.3mM)$ induced rhythmic increases in $[Ca^{2+}]_i$ and muscle contraction. However, sustained $[Ca^{2+}]_i$ and contracion were obtained at higher KCl concentration $({\geq}30.3mM)$ The rhythmic and sustained contraction closely associated with changes in $[Ca^{2+}]_i$ induced by high KCl. Carbachol $(3{\sim}30{\mu}M$ generated rhythmic increases with tonic component in $[Ca^{2+}]_i$ and muscle contraction. Myometrial contraction stimulated by carbachol was also closely correlated with change in $[Ca^{2+}]_i$. And the $[Ca^{2+}]_i/contraction$ relationships were similar when muscle strips were stimulated by high KCl and carbachol. Maximal concentration of carbachol $(10{\mu}M)$ and oxytocin(100 nM) increased $[Ca^{2+}]_i$ and contraction which were slightly greater than that of high KCl in non-pregnant myometrium, respectively. However, the $[Ca^{2+}]_i$ and contraction were strongly inhibited by verapamil $(10{\mu}M)$, a 1-type $Ca^{2+}$ channel blocker, as in the case of high KCl. Additionally, although carbachol further increased $[Ca^{2+}]_i$ and contraction induced by high KCl, these changes also strongly inhibited by application of verapamil. These results suggest that uterotonic agents, carbachol and oxytocin, induced contraction by increase in $[Ca^{2+}]_i$ through $Ca^{2+}$ influx than by a regulation of $Ca^{2+}-sensitization$ in non-pregnant myometrium.

• Journal of Nutrition and Health
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• 제37권8호
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• pp.645-654
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• 2004

This study examined the effect of excess calcium (Ca) on the iron (Fe) bioavailability and bone growth of marginally Fe deficient animals. Two groups of weanling female SD rats were fed either normal Fe (35 ppm) or Fe deficient diet (8 ppm) for 3 weeks. Then each group of animals were assigned randomly to one of three groups and were fed one of six experimental diets additionally for 4 weeks, containing normal (35 ppm) or low (15 ppm) Fe and one of three levels of Ca as normal (0.5%), high (1.0%), or excess (1.5%). Feces and urine were collected during the last 3 days of treatment. After sacrifice blood, organs, and femur bone were collected for analysis. Final body weight and average food intake were not affected by either the levels of dietary Ca or Fe. Low Fe diet significantly reduced the level of serum ferritin, however, for Hb, Hct, and TIBC no difference was shown than those in the normal Fe group. TIBC increased slightly by high and excess Ca intake in low Fe groups. For both normal and low Fe groups, high and excess Ca intakes reduced the apparent absorption of Fe and Fe contents of liver significantly (p < 0.05). Calcium contents in kidney and Femur of rats that were fed high and excess levels of Ca were significantly greater than those of normal Ca groups. However, weight, length, and breaking force of the bone were not affected by increased Ca intakes. Both in control and low Fe groups, high and excess intakes of Ca decreased the apparent absorption of Ca. These results indicate that the excess intakes of calcium than the normal needs would be undesirable for Fe bioavailability and that the adverse effects be more serious in marginally iron deficient growing animals. In addition bone growth and strength would not be favorably affected by high Ca intakes, though, the long term effect of increased Ca contents in bone requires further examination.

• 한국광물학회지
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• 제17권4호
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• pp.339-355
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• 2004

국내산 고품위 석회석은 그 지질 배경과 광상 유형에 따라 (1) 제천-단양 지구, (2) 삼척-태백-정선 지구 및 (3) 울진-안동 지구의 유형들로 구분된다. 제천-단양 지구에서 산출되는 석회석을 제외한 대부분의 국내산 고품위 석회석들은 석회암이 열수변질작용과 열변성작용을 받아 재결정되고 Ca이 부화된 양상을 이룬다. 국내산 고품위 석회석은 광물조성, 화학조성, 결정도 및 광물상의 차이에 따라 결정질 석회암형, 대리암형, 미정질 및 거정질 방해석 유형으로 구분된다. 이들에 대해 응용광물학적 관점에서 그 조성과 특성을 밝히기 위한 체계적인 시험 및 분석이 이루어졌다. 제천-단양 지구의 고품위 석회석들은 외견상 원암에 가까운 결정질 석회암 유형으로서, 낮은 결정도와 세립질 조직, 비교적 높은 CaO 함량(51～54 wt.%) 및 낮은 백색도의 광석 특성을 갖는다. 삼척-태백-정선 지구에서 산출되는 미정질(대개 0.2～0.3 mm) 및 거정질(2～15 cm) 고품위 석회석은 전형적인 열수변질형 광석으로서, 결정도에서 유형별로 서로 현격한 차이를 보이고 다소 편차가 심한 CaO 함유도(50～55 wt.%) 및 높은 백색도를 보이는 것이 특징이다. 특히 이 지역의 주된 광체인 미정질 방해석형 광석은 미세하고 균일한 결정도와 보다 균질한 조성(대개 > 52 wt.%)을 이룬다. 울진-안동 지구의 변성퇴적암류에서 산출되는 석회석들은 그 광상 유형과 산출상태에 따라 품위와 품질면에서 현격한 차이를 보인다. 이 같은 국내산 고품위 석회석의 광물특성과 화학조성상의 특징에 의거하여 지역별로의 광석 유형에 따라 적절한_개발 용도를 제시하였다.

• 한국지하수토양환경학회:학술대회논문집
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• 한국지하수토양환경학회 2002년도 추계학술발표회
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• pp.195-199
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• 2002

This study is for know chemistry of the representative soils from Keumsan, its relationships with dissolved compositions, and its absorption relationships within the flora. It has been done for two comparisons: 1) phyllite, shale and granite(PSG), and 2) granite and coal bearing shale(GC). Among the soil leachate of the PSG, cations are mainly low in the phyllite area while anions are mainly low in the granite area. In the soil compositions, Ca and Mg of the beans are high and Na is high in the granite area while Ca and Na of the perilla are high in the granite area and Mg is high in the phyllite area. In th both species, Na for the granite area and Mg for the phyllite area are high while Ca for the shale area is low. Among the flora, shale area shows low Ca and Mg contents while granite area shows slightly high Na contents, regardless the species. Compared with beans, perilla is low in the Mg and high in the Na contents. These relationships show that the contents of the soil leachate do not reflect absorption within the flora. Among the soil leachate of the GC, shale area is high in the most of the elements. Especially, SO$_4$ is over 15 times high In the phyllite area. In the soil, granite area shows high Ca, Na and low Mg contents. In the flora, the Miscanthus sinensis shows high Ca and Mg contents in the granite area while the Artemisia vulgaris shows high Ca, Ca and Mg contents in the shale area. These relationships for contents of the flora and soil leachate suggest that the flora has a different absorption according different species.

• 한국세라믹학회지
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• 제34권8호
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• pp.834-842
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• 1997

Controlled Ca impurity implanted inner crack-like pore in the high purity alumina single crystal, sapphire, had been created by micro-fabrication technique, which includes ion implantation, photo-lithography, Ar ion milling, and hot press technique. The morphological change and the healing of cracklike pore in Ca doped high purity single crystal alumina, sapphire, during high temperature heat treatment in vacuum were observed using optical microscopy. The dot-like surface roughening was developed and hexagon like crystal appeared on inner surface of crack-like pore after heat treatment. Bar type crystals, probably CaO.6Al2O3, were observed on the inner surface after 1 hour heat treatment at 1, 50$0^{\circ}C$, but this bar type crystal disappeared after 1 hour heat treatment at 1, $600^{\circ}C$. This disappearance means that there should be a little increase of Ca solubility limit to alumina at this temperatures.

• The Korean Journal of Physiology and Pharmacology
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• 제13권3호
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• pp.189-194
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• 2009

This study was designed to clarify the mechanism of the inhibitory effect of forskolin on contraction, cytosolic $Ca^{2+}$ level $([Ca^{2+}]_i)$, and $Ca^{2+}$ sensitivity in guinea pig ileum. Forskolin (0.1 nM ${\sim}$ 10 ${\mu}M$) inhibited high $K^+$ (25 mM and 40 mM)- or histamine (3 ${\mu}M$)-evoked contractions in a concentration-dependent manner. Histamine-evoked contractions were more sensitive to forskolin than high $K^+$-evoked contractions. Spontaneous changes in $[Ca^{2+}]_i$ and contractions were inhibited by forskolin (1 ${\mu}M$) without changing the resting $[Ca^{2+}]_i$. Forskoln (10 ${\mu}M$ ) inhibited muscle tension more strongly than $[Ca^{2+}]_i$ stimulated by high $K^+$, and thus shifted the $[Ca^{2+}]_i$-tension relationship to the lower-right. In histamine-stimulated contractions, forskolin (1 ${\mu}M$) inhibited both $[Ca^{2+}]_i$ and muscle tension without changing the $[Ca^{2+}]_i$-tension relationship. In ${\alpha}$-toxin-permeabilized tissues, forskolin (10 ${\mu}M$) inhibited the 0.3 ${\mu}M$ $Ca^{2+}$-evoked contractions in the presence of 0.1 mM GTP, but showed no effect on the $Ca^{2+}$-tension relationship. We conclude that forskolin inhibits smooth muscle contractions by the following two mechanisms: a decrease in $Ca^{2+}$ sensitivity of contractile elements in high $K^+$-stimulated muscle and a decrease in $[Ca^{2+}]_i$ in histamine-stimulated muscle.

• 한국가스학회지
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• 제5권4호
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• pp.27-32
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• 2001

온실효과의 주요 원인 물질인 이산화탄소를 고온$\cdot$고압에서 제거하기 위한 CaO 흡착제를 제조하였다. 흡착제는 석회석을 고압성형과 소성을 이용하여 제조하여 그 물성을 조사하고 회분식 흡착용기에서 흡착실험을 수행하였다. 세공면적은 성형압력으로 결정되며 세공분포는 이분산 형태를 갖는다. CaO의 $CO_2$ 흡착은 화학흡착이며 최대전환율은 $700^{\circ}C$에서 $80\%$에 근접한다.

• Journal of Nutrition and Health
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• 제26권8호
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• pp.915-924
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• 1993

To study the effect of menopause and dietary protein level on Ca metabolism, ovariectomy (OVAX) and sham operations were performed in 16-week old female rats. Each treatment group was fed for 16 weeks either 5%(L) or 50%(H) casein diets, forming SH, SL, OH, OL groups. High protein groups(SH, OH) showed higher Ca and hydroxyproline excretion in urine. Urinay hydroxyproline was also higher in OVAX, which tells the possibility of increased bone resorption by OVAX and by high dietary protein. At 16th wee, however, urinary Ca and hydroxyproline of SH caught up with OH group, whereas those of OL remained higher than SL. Therefore it seems that high dietary protein overrides the effect of OVAX with time. Urnary protein measured at 8th week was higher in high protein groups, especially in OH. GFR was not differ significantly among groups at 8th week. At 16th week, however, high protein groups showed twice the GFR value of low protein groups. Therefore the increase of urinary Ca and hydroxyproline in SH and OH groups can be explained partly by the increased GFR. The tendency of increased GFR and urinary excretion of protein, Ca, and hydroxyproline was most obvious in OH group. It seems that the effect of high protein diet is likely to accelerated by ovariectomy. The effect of Ovax and dietary protein on the composition of femur, scapular, and lumbar bones, was not pronounced. However, when only the high protein groups were compared, OVAX resulted in the reduction of bone weight, ash and Ca contents, especially in femur. The reason that was no significant effect on bone might be due to the short experimental period to induce that was no significant effect on bone might be due to the short experimental period to induce the changes on bone composition and dietary Ca content used in this experiment may have been high enough to prevent bone loss.

• Journal of Animal Science and Technology
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• 제64권5호
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• pp.871-884
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• 2022

Two experiments were conducted to evaluate the effects of calcium (Ca) levels in weanling pigs (Landrace × Yorkshire × Duroc). In experiment 1, one hundred and eighty weanling pigs were randomly allotted to one of the three treatments. The treatments were low (Ca 0.60% in phase 1 and 0.50% in phase 2), standard (Ca 0.72% in phase 1 and 0.66% in phase 2), and high (Ca 0.84% in phase 1 and 0.72% in phase 2). In experiment 2, hundred and forty weanling pigs were randomly assigned to one of four treatments differing in Ca levels (high and low) and sources (CaCl₂ and CaCO₃) in a 2 × 2 factorial arrangement. There were 10 pigs per replicate in both experiments, with 6 replicates in each treatment, and they were conducted in two phases (phase 1, days 0-14; phase 2, days 15-28). In experiment 1, body weight (BW), average daily gain (ADG), and growth to feed ratio (G/F) increased as the Ca level decreased (p < 0.05). P digestibility was higher in the low-Ca diet group than in the high-Ca diet group (p <0.05). In experiment 2, the final BW, ADG, and G/F increased in the CaCl₂ diet group compared with the case in the CaCO₃ diet group (p < 0.05). The digestibility of crude protein (CP), Ca, and P was higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Cl^- levels were higher in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). The bicarbonate (HCO_3-), base excess (BE), and electrolyte balance (EB) levels were lower in the CaCl₂ diet group than in the CaCO₃ diet group (p < 0.05). Hematocrit increased as the Ca level decreased (p < 0.05). The HCO_3- interacted with the Ca sources and thus, affected the Ca levels (p < 0.05). Bone ash, Ca, and P were downregulated in the low-Ca diet group compared with the case in the high-Ca diet group. Overall, the low dietary Ca supplementation led to greater growth performance. Furthermore, CaCl₂ appeared to be a better Ca source than CaCO₃ because of the greater digestibility of CP, Ca, and P, and improved EB.

• Journal of Nutrition and Health
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• 제29권9호
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• pp.943-949
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• 1996

Bone mineral density depends largely on the status of dietary minerals such as Ca, P, Mg, and F and proteins, physical activities, parathyroid hormone(PTH), calcitonin(CT), and vitamin D. The decrease of bone density often results in bone fractures and osteoporosis which is prevalent among postmenopausal women. This study was intended to examine the role of parathyroid hormone, calcitonin and cholecaliferol in bone density of mice that were fed different dual photon energy beams. We have measured three major parts of the bone : whole body, head and femur. The results are summarized as follows : 1) Bone mineral density (BMD) was more increased by feeding high Ca diet compared to that of the low Ca diet. 2) Both PTH and Vit D3 enhanced BMD in all of the different Ca levels. 3) When the dietary Ca was deequate CT showed a synergistic effect with PTH in boosting bone density, while CT+Vit D3 showed a negative effect. 4) CT tended to inhibit the effect of increasing bone density by PTH and Vit D3 in medium and low Ca groups. 5) The effect of increasing bone density by PTH in the head of mouse increased when dietary Ca was lower : The increment of bone density by PTH in high, medium, and low Ca was 3%, 8%, 19%, respectively. 6) Femur bone density was affected significantly by dietary Ca levels than hormones. The above observations indicate that bone mineral density can be improved by high dietary Ca and hormone injections including PTH, CT and cholecalciferol, and thus proper dietary and hormonal treatment may be used in preventing bone fractures and osteoporosis.