Biomedical subjects

Shin Yoon Kim

Publications and source records attributed to Shin Yoon Kim.

3 recordsLinked to original sources

PubMed2006

Methylation of the mouse DIx5 and Osx gene promoters regulates cell type-specific gene expression.

Dlx5 and Osx are master regulatory proteins essential for initiating the cascade leading to osteoblast differentiation in mammals, but the mechanism of osteoblast-specific expression is not fully understood. DNA methylation at CpG sequences is involved in tissue and cell type-specific gene expression. We investigated the methylation status of Dlx5 and Osx in osteogenic and nonosteogenic cell lines by methylation-specific PCR (MSP). The CpG dinucleotides of the Dlx5 and Osx promoter regions were unmethylated in osteogenic cell lines transcribing these genes but methylated in nonosteogenic cell lines. Treatment of C2C12 cells with 5-AzadC induced dose- and time-dependent expression of Dlx5 and Osx mRNA by demethylating the corresponding promoters. Furthermore the mRNAs for the osteoblast markers ALP and OC, which were undetectable in untreated cells, gradually increased after 5-AzadC treatment. In addition, BMP-2 stimulation induced Dlx5 expression by hypomethylating its promoter. These findings suggest that DNA methylation plays an important role in cell type-specific expression of Dlx5 and Osx.

Animals↗

PubMed2004

Association between bone mineral density and LDL receptor-related protein 5 gene polymorphisms in young Korean men.

Recently, It has been reported that the LDL receptor-related protein 5 (LRP5) regulates bone formation, and that mutations of the gene cause osteoporosis-pseudoglioma syndrome or high bone mass phenotypes. However, the mutations cannot explain a genetic trait for osteoporosis in the general population because of their rarity. From 219 Korean men aged 20-34 yr, we looked for six known polymorphisms causing amino acid changes in the LRP5 coding region, and investigated their association with bone mineral density (BMD) at the following anatomical sites: lumbar spine (L2-L4) and the left proximal femur (femoral neck, Ward's triangle, trochanter and shaft). We found that the Q89R polymorphism was significantly associated with BMD at the femoral neck and Ward's triangle (p=0.004 and <0.001, respectively). However, after adjusting for age, weight and height, a statistically significant association only occurred at the Ward's triangle (p=0.043), and a marginal association was observed at the femoral neck (p=0.098). No A400V, V667M, R1036Q and A1525V polymorphisms were found, and no statistically significant association was found between the A1330V polymorphism and BMD at any sites. Although we failed to demonstrate a clear association between the LRP5 polymorphism and peak bone mass in young men, the present study suggests that larger-scale studies on the Q89R polymorphism need to be performed.

Adult↗

PubMedDate not supplied

Fractional quantitative computed tomography for bone mineral density evaluation: accuracy, precision, and comparison to quantitative computed tomography.

OBJECTIVE: To evaluate bone mineral density considering its distribution, fractional quantitative computed tomography (fQCT) was designed and verified. METHODS: Quantitative computed tomography (QCT) was performed at 64 areas in 10 swine long bones. Fractional quantitative computed tomography was measured at the identical areas as the proportion of pixels showing a bone density higher than 130 mg/mL equivalent. All target areas were extracted and incinerated to measure apparent ash bone density. Based on standard references, the accuracy and precision of fQCT were evaluated and the results were compared with conventional QCT results. RESULTS: The correlation coefficient between fQCT and apparent ash bone density was 0.843 (P < 0.0001). The fQCT showed good correlation with volume fraction (r = 0.88, P < 0.0001). The coefficient of variation of fQCT was 0.42%. The fQCT revealed higher accuracy and precision than the results of QCT. CONCLUSION: Fractional quantitative computed tomography was designed and verified as a reliable method to measure bone mineral density.

Animals↗