• International Journal of Oral Biology
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• v.30 no.1
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• pp.23-30
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• 2005

Bone remodeling is a process controlled by the action of two major bone cells; the bone forming osteoblast and the bone resorbing osteoclast. In the process of osteoclastogenesis, stromal cells and osteoblast produce RANKL, OPG, and M-CSF, which in turn regulate the osteoclastogenesis. During the bone resorption by activated osteoclasts, extracellular $Ca^{2+}/{PO_4}^{2-}$ concentration and degraded organic materials goes up, providing the hypertonic microenvironment. In this study, we tested the effects of hypertonicity due to the degraded organic materials on osteoclastogenesis in co-culture system. It was examined the cellular response of osteoblastic cell in terms of osteoclastogenesis by applying the sucrose, and mannitol, as a substitute of degraded organic materials to co-culture system. Apart from the sucrose, mannitol, and NaCl was tested to be compared to the effect of organic osmotic particles. The addition of sucrose and mannitol (25, 50, 100, 150, or 200 mM) to co-culture medium inhibited the number of tartrate-resistant acid phosphatase (TRAP) positive multinucleated cells induced by 10 nM $1{\alpha},25(OH)_2vitaminD_3$ ($1{\alpha},25(OH)_2D_3$). However, NaCl did exert harmful effect upon the cells in this co-culture system, which is attributed to DNA damage in high concentration of NaCl. To further investigate the mechanism by which hypertonicity inhibits $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis, the mRNA expressions of receptor activator of nuclear factor (NF)-kB ligand (RANKL) and osteoprotegerin (OPG) were monitored by RT-PCR. In the presence of sucrose (50 mM), RANKL mRNA expression was decreased in a dose-dependent manner, while the change in OPG and M-CSF mRNA were not occurred in significantly. The RANKL mRNA expression was inhibited for 48 hours in the presence of sucrose (50 mM), but such a decrement recovered after 72 hours. However, there were no considerable changes in the expression of OPG and M-CSF mRNA. Conclusively, these findings strongly suggest that hypertonic stress down-regulates $1{\alpha},25(OH)_2D_3$-induced osteoclastogenesis via RANKL signal pathway in osteoblastic cell, and may playa pivotal role as a regulator that modulates osteoclastogenesis.

• Journal of Animal Science and Technology
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• v.51 no.4
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• pp.295-306
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• 2009

This experiment was conducted to investigate the effects of dietary calcium (Ca) and vitamin $D_3$ metabolite on eggshell quality and hatching egg production in aged egg-type breeder hens. A total of five hundred and forty 60-week-old Hy-Line Brown breeder hens were randomly allocated to nine treatments in a $3\times3$ factorial design to determine the effects of dietary Ca levels (3.3, 3.9, and 4.5%), combined with three levels of 25-hydroxycholecalciferol [25-$(OH)D_3$ 0, 75, and $150{\mu}g/kg$], on eggshell quality and egg production for 10 weeks. There were significant Ca and 25-$(OH)D_3$ effects (P<0.01) on egg production rate. There was a linear (P<0.01) increase in eggshell strength and thickness with increasing dietary Ca and 25-$(OH)D_3$ levels. Dietary 25-$(OH)D_3$ had a significant effect (P<0.05) on hatchability of egg although fertility was not influenced by dietarylevels of Ca and 25-$(OH)D_3$. Dietary Ca levels affected Ca content in tibia (P<0.05). These results indicated that relatively high levels of dietary Ca in combination with 25-$(OH)D_3$ had a beneficial effect on improving eggshell quality and reproductive performance in aged egg-type breeder hens.

• Journal of Nutrition and Health
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• v.45 no.1
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• pp.20-29
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• 2012

Metabolic syndrome (MetS) has become a global epidemic. In particular, it is known that there is a dramatic increase in the prevalence of MetS among women during the postmenopausal period. Recently, accumulating studies have suggested that vitamin D deficiency may be inversely associated with the risk factors regarding MetS. However, evidence from postmenopausal women is limited. In this study, we examined the association between the serum 25-hydroxyvitamin D [25(OH)D] and the MetS in Korean adult women aged 20-69 years (n = 2,618) by using the 2007-2008 Korean National Health and Nutrition Examination Survey data. The geometric mean of plasma 25(OH)D were $17.16{\pm}6.28\;ng$/mL and $20.20{\pm}7.69\;ng$/mL for premenopausal and postmenopausal women, respectively. The percentages of vitamin D deficiency [25(OH)D < 12 ng/mL] were 22.5% and 14.4%, respectively. MetS was more prevalent in postmenopausal women (43.0%) compared with premenopausal women (11.2%). When serum concentrations of 25(OH)D were categorized in quintiles, there was no relationship in the prevalence of MetS in both premonopausal and postmenopausal women. However, in premenopausal women, compared with the lowest 25(OH)D quintile, the odds ratio for hypertriglyceridemia in the highest quintile was 0.57 (95% CI 0.34-0.95, $P_{trend}$ = 0.041) and for low serum HDL cholesterol 0.60 (95% CI 0.42-0.85, $P_{trend}$ = 0.014) after adjusting for all potential confounders. On the other hand, we observed the tendency of an inverse relationship for 25(OH)D regarding low serum HDL cholesterol (OR 0.78, 95% CI 0.50-1.22, $P_{trend}$ = 0.029) and a direct relationship with abdominal obesity (OR 1.94, 95% CI 1.01, 3.74, $P_{trend}$ = 0.049) in postmenopausal women. Further studies are needed to confirm these findings in other research settings.

• Journal of Nutrition and Health
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• v.47 no.2
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• pp.113-123
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• 2014

Purpose: Vitamin D has been known to play an important role in the central nervous system and brain functions in the human body, and cumulative evidence has shown that vitamin D deficiency might be linked with various mental health conditions. Epidemiologic studies have shown that vitamin D deficiency may be associated with higher risk of depression in the US and European populations. However, limited information is available regarding the association between vitamin D status and depression in the Korean population. The objective of this study was to examine the associations between vitamin D levels and prevalence of depression. Methods: We conducted a cross-sectional analysis using nationally representative data from the 2008-2010 Korean National Health and Nutrition Examination Survey from which serum 25-hydroxyvitamin D concentrations were available. A total of 18,735 adults who had available demographic, dietary, and lifestyle information were included in our analysis. We defined "depression" with a diagnosis by a physician. "Depressed condition" was defined as having feelings of sadness or depression without diagnosis by a physician. Results: The prevalence of depression was 1.63% and 5.43% in Korean men and women, respectively; 12.5% of men and 26.1% of women were defined as the group having depressed conditions. In multivariate logistic regression models, no significant associations were observed between vitamin D status and prevalence of depression or depressed conditions in Korean men and women. Conclusion: We found no association between vitamin D insufficiency and depression/depressed conditions in Korean adults. Future large prospective studies and randomized controlled trials are needed to confirm this relationship.

• Journal of Practical Agriculture & Fisheries Research
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• v.18 no.1
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• pp.13-24
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• 2016

Sixty Hanwoo steers(15 months of age; 409±29.2 kg of BW) were used to evaluate the effects of dietary vitamins A and D restriction on carcass characteristics. Steers were allotted randomly to 1 of 4 treatments: Control(diet supplemented with vitamins A, D and E), -A (diet supplemented with vitamins D and E), -D(diet supplemented with vitamins A and E) and -AD(diet supplemented with vitamin E only). Steers were fed the experimental diet for a period of 8 months(until 23 months of age), and then supplemented with vitamins A and D at 0.05% of the diet(as fed-basis) from 24 to 26 months of age, and at 0.1% of the diet from 27 to 31 months of age(harvesting time). Dietary restriction of vitamins A and D did not affect DM intake, daily gain and feed conversion ratio. But the concentration of serum retinol was significantly(P<0.05) decreased by vitamin A restriction with the lowest concentration being seen at 23 months of age(345.0 ㎍/L and 326.7㎍/L for control and -D treatment versus 169.3 ㎍/L and 175.4 ㎍/L for -A and -AD treatments). The serum concentration of 25(OH)D₃ was also decreased significantly(P<0.05) by vitamin D restriction and the lowest concentration was seen at 18 months of age(53.7ng/ml and 61.8ng/ml for control and - A treatment versus 24.0 ng/ml and 24.5 ng/ml for -D and -AD treatments). After the restriction period of vitamins A and D, the concentrations of retinol and 25(OH)D₃ for - A, -D and -AD treatments were recovered at those of control. Dietary restriction of vitamins A and D did not affect carcass weight, backfat thickness, ribeye area, quality grade and yield grade. But marbling score was significantly increased by vitamin A restriction compared with control(6.73, 6.87 and 5.73 for -A, -AD and control, respectively). The results of the present study suggested that dietary vitamin A restriction could improve marbling score in Hanwoo steers.

• Clinical and Experimental Pediatrics
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• v.61 no.3
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• pp.90-94
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• 2018

Purpose: The present study aimed to determine the relationship between serum 25-hydroxyvitamin D (25(OH)D) level and Urinary tract infections (UTIs) in children. Methods: In this case-control study, 70 children with UTI (case group) were compared with 70 healthy children (control group) in terms of serum 25(OH)D levels. The children were between 1 month and 12 years of age. Serum 25(OH)D levels were measured using enzyme-linked immunosorbent assay (ELISA). The results were analyzed and compared between both groups. Results: Among 70 children with UTI (case group), 5 children (7.2%) were male and 65 (92.8%) were female. Among the healthy children (control group), 9 (12.8%) and 61 children (87.2%) were male and female, respectively (P=0.39). The $mean{\pm}standard$ deviation of age in the case and control groups were $53.2{\pm}35.6$ and $36.1{\pm}60.2months$, respectively (P=0.24). The mean level of serum 25(OH)D in the case group was significantly higher than that of the control group ($20.4{\pm}8.6ng/mL$ vs. $16.9{\pm}7.4ng/mL$, P=0.01) Conclusion: This study showed that there was a relationship between serum 25(OH)D levels and UTI in children. It seems that 25(OH)D plays a role in the pathogenesis of UTI.

• Journal of the Korean Society of School Health
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• v.30 no.2
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• pp.146-153
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• 2017

Purpose: The purpose of this study was to identify the association between physical activity and vitamin D deficiency status among Korean adolescents. Methods: This is cross-sectional analysis of Korean adolescents aged 10-18 years from the 5th Korea National Health and Nutrition Examination Survey(KNHANES 2010-2012; n=2,384). We estimated the prevalence of vitamin D deficiency and identified the correlations with the strength of physical activity. $x^2$ test, t-test, and multiple logistic regression using complex sample analysis were done. The odds ratio of vitamin D deficiency by physical activity was calculated using complex sample multivariate logistic regression analysis. Results: The prevalence of vitamin D deficiency was 78.2%. The mean serum 25 (OH) D level in deficiency group and non-deficiency group was 14.4ng/mL, 23.7ng/mL respectively. Differences by age strata (the prevalence ranging from 68.5% to 86.3%) and gender (78.6% for boy and 84.5% for girl) were identified. Among adolescents aged 16-18 or girl in vigorous physical activity, a significant correlation between vitamin D deficiency and physical activity was observed, whereas no significant correlation were found among adolescents in moderate physical activity. Conclusion: In conclusion, vigorous physical activity was associated with vitamin D deficit in Korean adolescents. Thus, intervention programs enhancing vigorous activity than moderate activity need to be developed in schools and community.

• Food Science and Industry
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• v.55 no.3
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• pp.276-283
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• 2022

Vitamin D is a fat-soluble vitamin helps to retain calcium and phosphorus but also has shown to affect immune regulation and homeostasis. In humans, vitamin D3 and vitamin D2 and their metabolite has intensively studied in both innate and adaptive immune system that they are important to regulate overwhelmed inflammation. The vitamin D receptor is a nuclear hormone receptor which regulate various downstream target gene expressions as a transcription factor related to metabolism, immune regulation, etc. Vitamin D deficiency is a high-risk factor for inflammatory diseases like autoimmune disease and allergy. In addition, reduced vitamin D seem to correlate with susceptibility to the virus infection such as HIV and COVID-19. In this review, we will summarize up-to-date vitamin D's role in various immune cells, immune regulatory functions during autoimmune, allergic, and infectious diseases. We will also discuss about vitamin D supplement effects in human trial studies for COVID-19.

• Animal cells and systems
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• v.13 no.4
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• pp.363-370
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• 2009

Since vitamin $D_3$ is an important regulator of osteoblastic differentiation, a presently-established vitamin $D_3$-entrapped calcium phosphate film (VCPF) was evaluated for hard tissue engineering. The entrapped vitamin $D_3$ more rapidly induced bone nodule formation. To characterize the cellular events leading to regulations including faster differentiation, signal transduction pathways were investigated in osteoblastic MG63 cells at a molecular level. Major signaling pathways for MG63 cell proliferation including phosphatidylinositol-3-kinase, extracellular signal-regulated kinase, c-Jun N-terminal kinase and focal adhesion kinase pathways were markedly down-regulated when cells were cultured on calcium phosphate film (CPF) and VCPF. This agreed with our earlier observations of the immediate delay in proliferation of MG63 cells upon culture on CPF and VCPF. On the other hand, the p38 mitogen-activated protein kinase (p38 MAPK) and protein kinase A (PKA) pathways were significantly up-regulated on both CPF and VCPF. CPF alone could simulate differential behaviors of MG63 cells even in the absence of osteogenic stimulation and entrapment of vitamin $D_3$ within CPF further amplified the signal pathways, resulting in continued promotion of MG63 cell differentiation. Interplay of p38 MAPK and PKA signaling pathways likely is a significant event for the promotion of differentiation and mineralization of MG63 cells.

• Korean Journal of Clinical Laboratory Science
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• v.47 no.4
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• pp.318-323
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• 2015

The aim of this study was to assess the association of metabolic syndrome and Vitamin D in Korean adults. The study subjects were Korean menopausal woman (n=4,340) who participated in the Korea National Health and Nutrition Examination Survey 2010~2012. After adjusting for factors such as age, body mass index, total cholesterol, smoking, and regular exercise, the mean 25(OH)D levels ($M{\pm}SE$) decreased with increasing metabolic syndrome score (MSS) (MSS 0, $18.18{\pm}0.29ng/Ml$; MSS 1, $18.09{\pm}0.21ng/mL$; MSS 2, $18.07{\pm}0.19ng/mL$; MSS 3, $18.04{\pm}0.21ng/mL$; MSS ${\geq}4$, $17.27{\pm}0.23ng/mL$), and the mean 25(OH)D level ($M{\pm}SE$) for metabolic syndrome ($17.66{\pm}0.16ng/mL$) decreased in comparison to non-metabolic syndrome ($18.11{\pm}0.14ng/mL$). In conclusion, our results suggest that an increase in metabolic syndrome score or metabolic syndrome are inversely associated with the vitamin D levels.