• The Korean Journal of Nuclear Medicine Technology
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• v.24 no.1
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• pp.33-38
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• 2020

Purpose Vitamin D is essential for maintaining bone health, controling cell proliferation or differentiation, strengthening immune function by controlling calcium metabolism in the body. Vitamin D deficiency can lead to increase the risk of rickets, osteoporosis, cardiovascular disease, diabetes and cancer. Especially, South Korea is one of the highest population proportion of vitamin D deficiency. Accurate determination of levels of 25-OH-VitD or 25-OH-VitD3 in blood serum is required for the diagnosis and treatment of vitamin D deficiency. In this study, radioimmunoassay of 25-OH-VitD and 25-OH-VitD3 was performed and compared to evaluate the effectiveness of Vitamin D radioimmunoassay. Materials and Methods Serum 25-OH-VitD and 25-OH-VitD3 levels were measured using radioimmunoassay. The interrelationship, reproducibility and population distribution rate were evaluated. In addition, the internal quality control was performed at Asan Medical Center from April 2017 to June 2019 and the result of external quality control (Interagency proficiency evaluation) of first and second half of 2018 hosted by the Korean Society of Nuclear Medicine Technology (KSNMT). Both tests were measured by same manufacturer's reagent. Results 25-OH-VitD showed a strong positive correlation on 97 samples, as 25-OH-VitD3 x 0.9 + 0.3 (R>0.9). In repeated measurement, the average Diff(%) value of the reproducibility evaluation of 25-OH-VitD and 25-OH-VitD3 were 7.7% and 7.4%, respectively. Population distribution results showed no statistically significant differences(p>0.05). The resultant value of internal quality control, which measured from April, 2017 to June 2019 in Blood test room of Nuclear Medicine at Asan Medical Center, showed average (CV%) 6.2% and 6.8%, respectively. As a result of the external quality control (interagency proficiency evaluation) Z value obtained under 2.0, as shown below; Conclusion The interrelationship, reproducibility, population distribution rate, internal quality control and external quality control between 25-OH-VitD and 25-OH-VitD3 radioimmunoassay shows superior outcome. Radioimmunoassay, which can be alone measured in the blood as 25-OH-VitD or 25-OH-VitD3, is considered suitable screening tests for the diagnosis of vitamin D deficiency.

• Tuberculosis and Respiratory Diseases
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• v.78 no.3
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• pp.232-238
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• 2015

Background: A relationship between low vitamin D levels and the development or outcomes of respiratory diseases has been identified. However, there is no data on the vitamin D status in patients with acute eosinophilic pneumonia (AEP). We evaluated the vitamin D status in patients with AEP among South Korean military personnel. Methods: We prospectively compared the serum levels of total 25-hydroxyvitamin D [25(OH)D], 25(OH)D3, and 25(OH)D2 among patients with AEP, pulmonary tuberculosis (PTB), and community-acquired pneumonia (CAP). Results: In total, 65 patients with respiratory diseases, including AEP (n=24), PTB (n=19), and CAP (n=22), were identified. Of the 24 patients with AEP, 2 (8%) had deficient total 25(OH)D levels (<10 ng/mL), 17 (71%) had insufficient total 25(OH)D levels (${\geq}10$ to <30 ng/mL), and only 5 (21%) had sufficient total 25(OH)D levels (${\geq}30$ to <100 ng/mL). The difference in the total 25(OH)D levels among patients with AEP, PTB, and CAP was not statistically significant (p=0.230). The median levels of total 25(OH)D, 25(OH)D3, and 25(OH)D2 were 22.84, 22.84, and 0.00 ng/mL, respectively, and no differences in the 25(OH)D level were present among patients with AEP, PTB, and CAP with the exception of the total 25(OH)D level between patients with AEP and PTB (p=0.042). Conclusion: We have shown that low vitamin D levels are frequently found in patients with AEP and are comparable with those in patients with PTB and CAP.

• Journal of the Korean Society of Food Science and Nutrition
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• v.27 no.1
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• pp.141-148
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• 1998

This study describes the effects of 1,25-dihydroxyvitamin D3[1,25(OH)2D3, calcitriol] analog, 1,25(OH)2-16ene-23yne-D3 on proliferatin and differentiatin of the human histiocytic lymphoma cell line U937. This paper also describes the effects of 1,25(OH)2-16ene-23yne-D3 on ${\gamma}$-interferon(IFN-${\gamma}$) synthesis by phytohemagglutinin-activated peripheral blood lymphocytes(PBLs). In the present investigation, 1,25(OH2)-16ene-23yne-D3 was compared to the natural metablite of vitamin D3, 1,25(OH)2D3. 1,25(OH)2-16ene-23yne-D3 was more potent than 1,25(OH)2D3 for inhibition of proliferation and induction of differentiation of U937 cells, Its effects on inhibition of proliferation was about 30-fold more potent than 1,25(OH)2D3. On induction of differentiation as measured by nonspecific esterase (NSE) activity and morphologic change, this analog morphologically and functionally differentiated U937 cells to monocyte-macrophage phenotype showing a decrease of N/C ration in Giemsa staining and the increase of adherence ability of surface. After 3 days in culture, a more significant supression of IFN-${\gamma}$ synthesis analog on supression of IFN-${\gamma}$ synthesis was a dose-dependent manner, with peak activity at 10-7M. The strong direct effects of 1,25(OH)2-16ene-23yne-D3 on cell proliferation and cell differentiation, make this compound an interesting candidate for clinical studies for several types of malignancies, and the effects on supression of IFN-${\gamma}$ synthesis provide the further evidence for a role of 1,25(OH)2-16ene-23yne-D3 in immunoregulation.

• The korean journal of orthodontics
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• v.25 no.3 s.50
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• pp.333-339
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• 1995

The hormonally active vitamin D metabolite, 1,25-dihydroxy vitamin $D_3[1.25-(OH)_2D_3]$ is one of the several humoral factors that may regulate osteoblast differentiation. The purpose of this study was to evaluate the effects of $1,25-(OH)_2D_3$ on the PDL cells. Human PDL cells were prepared from the first premolar tooth extracted for the orthodontic treatment and they were incubated in the environment of $37^{\circ}C,\;5\%\;CO_2\;and\;95\%$ humidity. $[{^3}H]$-thymidine incorporation as a measure of proliferation potential and alkaline phosphatase activity were evaluated at 10nM, 100nM $1,25-(OH)_2D_3$. The observed results were as follows. 1. $1,25-(OH)_2D_3$ was significantly enhanced $[{^3}H]$-thymidine incorporation at 100nM, But did not affect by 10nM. 2. $1,25-(OH)_2D_3$ was significantly increased alkaline phosphatase activity at 1 day and 6 days in a dose-dependent manner.

• Nutrition Research and Practice
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• v.9 no.2
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• pp.158-164
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• 2015

BACKGROUND/OBJECTIVES: Vitamin D deficiency is common in hemodialysis patients. The aim of this study was to identify whether or not sun exposure and dietary vitamin D intake have effects on serum 25-hydroxyvitamin D (25(OH)D) status in hemodialysis (HD) patients. The objective was to identify the main determinants of serum vitamin D status in the study subjects. SUBJECTS/METHODS: A cross-sectional study of 47 HD patients (19 males and 28 females) was performed. We assessed serum 25(OH)D and $1,25(OH)_2D$ levels between August and September 2012 and analyzed the prevalence of vitamin D deficiency in HD patients. To evaluate the determinants of serum 25(OH)D levels, we surveyed dietary vitamin D intake, degree of sun exposure, and outdoor activities. To compare biological variables, serum 25(OH)D was stratified as below 15 ng/ml or above 15 ng/ml. RESULTS: Mean 25(OH)D and $1,25(OH)_2D$ levels were $13.5{\pm}5.8ng/ml$ and $20.6{\pm}11.8pg/ml$, respectively. The proportions of serum 25(OH)D deficiency (< 15 ng/ml), insufficiency (15-< 30 ng/ml), and sufficiency (${\geq}30ng/ml$) in subjects were 72.4%, 23.4%, and 4.3%, respectively. Prevalence of vitamin D deficiency in female patients was 78.6%, whereas that in males was 63.2% (P = 0.046). Vitamin D intake and sun exposure time were not significantly different between the two stratified serum 25(OH)D levels. Dietary intake of vitamin D did not contribute to increased serum 25(OH)D levels in HD patients. The main effective factors affecting serum 25(OH)D status were found to be the sun exposure and active outdoor exercise. CONCLUSIONS: Hypovitaminosis D is common in HD patients and is higher in females than in males. Sun exposure is the most important determinant of serum 25(OH)D status in HD patients.

• Journal of the Korean Society of Food Science and Nutrition
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• v.24 no.1
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• pp.1-9
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• 1995

1, 25(OH)2-23ene-D3 is a novel vitamine D3 analog which has a double bond between C-23 and C-24. We describe the effects of this analog on cell differentiation and cell proliferation in vitro using the human histiocytic lymphoma cell line U937, and on calcium metabolism in rats in vivo. In the present investigation 1, 25(OH)2-23ene-D3 was compared to the natural metabolite of vitamin D3, 1$\alpha$, 25-dihydroxycholecalciferol[1, 25(OH)2-23ene-D3 was more potent than 1, 25(OH)2-23ene-D3 for inhibition of proliferation and induction of differentiation of U937 cells. Especially, its effect on induction of differentiation, as measured by superoxide production and nonspecific esterase(NSE) activity, was about 20-fold more potent that 1, 25(OH)2-23ene-D3. This analog morphologically and functionally differentiated U937 cells to monocyte-macrophage phenotype showing a decrease of N/C ratio in Giemsa staining and the increase of adherence ability to surface. Intraperitoneal administration of 1, 25(OH)2-23ene-D3 to rats showed that the compound had at least 50 times less activity than 1, 25(OH)2-23ene-D3 in causing hypercalcemia and hypercalciuria. The strong direct effects of 1, 25(OH)2-23ene-D3 on cell proliferation and cell differentiation, coupled with its decreased activity of calcium metabolism make this compound an interesting candidate for clinical studies including patients with leukemia, as well as several skin disorders, such as psoriasis.

• Journal of Nutrition and Health
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• v.29 no.7
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• pp.747-757
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• 1996

In this study, the serum level of 25-hydroxyvitamin D(25-(OH)D) was measured by high pressure liquid chromatography(HPLC), and factors affecting it were investigated in 72 young adults age ranging from 21 years to 39 years with normal bone density. The mean level of serum 25-(OH)D was 20.0$\pm$6.8ng/ml in males and 26.1$\pm$12.3ng/ml in females, which was significantly higher in females (p<0.01). The serum level of parathyroid hormone(PTH) showed a negative correlation with that of 25-(OH)D(p<0.05). Time spent outdoors in a day correlated positively with the serum level of 25-(OH)D(p<0.01). During the day, a specific time between 12:00 a.m. and 2:00 p.m. showed the most significant correlation with the level of 25-(OH)D(p<0.005). Among the nutrients studied, fat and vitamin D intake were positively correlated with the serum 25-(OH)D level. Stepwise multiple regression analysis showed that the serum level of 25-(OH)D could be fit by vitamin D intake(34.7% explained), serum PTH level (27.3% explained) and the time spent outdoors during the specific time(28.4% explained).1996)

• Nutrition Research and Practice
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• v.5 no.2
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• pp.132-139
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• 2011

Evidence of the association between 25-hydroxyvitamin D (25(OH)D) and metabolic syndrome (MeS) remains uncertain and incongruent. This study aimed to determine the association between 25(OH)D and MeS among Jordanian adults. A complex multistage sampling technique was used to select a national population-based household sample. The present report deals exclusively with adults aged > 18 years who had complete information on all components of MeS (n = 3,234). A structured questionnaire was used to collect all relevant information. Anthropometric, clinical, and laboratory measurements were obtained. MeS was defined according to the International Diabetes Federation (IDF) definition. Of the total, 42.0% had MeS and 31.7% had 25(OH)D < 30 ng/ml. In a stratified analysis, the prevalence of MeS did not differ significantly between subjects with low and normal 25(OH)D levels for men and women in all age groups. In the multivariate analysis, the odds of MeS were not significantly different between subjects with low and normal 25(OH)D levels (OR = 0.85, 95% CI: 0.70, 1.05, P-value = 0.133). The association between 25(OH)D and MeS remained non-significant when 25(OH)D was analyzed as a continuous variable (OR = 1.004, 95% CI; 1.000, 1.008, P = 0.057) and when analyzed based on quartiles. None of the individual components of MeS were significantly associated with 25(OH)D level. This study does not provide evidence to support the association between 25(OH)D level and MeS or its individual components. Prospective studies are necessary to better determine the roles of 25(OH)D levels in the etiology of MeS.

• Nutrition Research and Practice
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• v.16 no.6
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• pp.745-754
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• 2022

BACKGROUND/OBJECTIVES: The incidence of cardiovascular diseases (CVDs) has increased worldwide. Although a low serum vitamin D level is known to be associated with the risk of CVD, the mechanism is not well understood yet. The aim of this study was to determine the relationship of serum 25-hydroxyvitamin D₃ (25[OH]D) with homocysteine and apolipoprotein B (ApoB). SUBJECTS/METHODS: Of 777 subjects recruited from one health promotion center for routine heath exam from January 2010 to December 2016, 518 subjects were included in this study. Serum 25(OH)D, serum homocysteine, and other metabolic parameters including ApoB were analyzed. Simple and partial correlations were carried out after adjustments. Simple linear regression analysis was used for precise correlation of parameters. Multivariate regression analysis was done to know which factor (serum homocysteine or ApoB) was more related to serum 25(OH)D after adjustments. Finally, logarithms of homocysteine concentrations according to tertiles of serum 25(OH)D were compared. RESULTS: After sex and age adjustments, serum 25(OH)D showed negative correlations with serum homocysteine (r' = -0.114) and ApoB (r' = -0.098). In simple linear regression analysis, serum 25(OH)D showed a significant negative correlation with ApoB (P = 0.035). However, in multivariate regression analysis, serum 25(OH)D was significantly associated with serum homocysteine after adjustments (P = 0.022). In addition, serum homocysteine concentration was significantly high in the lowest 25(OH)D group (P = 0.046). CONCLUSION: Serum 25(OH)D concentration showed a stronger negative association with serum homocysteine than with ApoB.

• Nutrition Research and Practice
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• v.13 no.6
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• pp.498-508
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• 2019

BACKGROUND/OBJECTIVES: Lower circulating 25-hydroxyvitamin D [25(OH)D] levels are associated with a higher risk of hypertension (HTN); however, it remains unclear whether the relationship is causal. We aimed to evaluate the causal effects of circulating 25(OH)D levels on the prevalence of HTN in the Korean population using the Mendelian randomization (MR) approach. SUBJECTS/METHODS: Epidemiological data, serum 25(OH)D data, and genomic DNA biospecimens were obtained from 2,591 participants, a subset of the study population in the Korea National Health and Nutrition Survey 2011-2012. Five 25(OH)D-related single nucleotide polymorphisms (SNPs; DHCR7 rs12785878, CYP2R1 rs10741657, CYP2R1 rs12794714, CYP24A1 rs6013897, and GC rs2282679), identified a priori from genome-wide association studies, were used as instrument variables (IVs) for serum 25(OH)D levels. In the MR analysis, we performed IV analyses using the two-stage least squares method. RESULTS: In the observational analysis, circulating 25(OH)D levels were found to be inversely associated with the HTN prevalence in ordinary least squares models (odds ratio: 0.97, 95% confidence interval: 0.96, 0.99) after adjusting for the potential confounders. There were differences in the circulating 25(OH)D levels across genotypes of individual SNPs. In the MR analysis, using individual SNPs as IVs, 25(OH)D levels were not associated with the HTN prevalence. CONCLUSIONS: We found no association between genetically determined circulating 25(OH)D levels and HTN in Korean adults. Our results are listed owing to the relatively small sample size and possible weak instrument bias; therefore, further studies are needed to confirm these results.