[show abstract][hide abstract] ABSTRACT: The Hox genes, which are organized into clusters on different chromosomes, are key regulators of embryonic anterior-posterior (A-P) body pattern formation and are expressed at specific times and in specific positions in developing vertebrate embryos. Previously, we have shown that histone methylation patterns are closely correlated with collinear Hox gene expression patterns along the A-P axis of E14.5 mouse embryos. Since histone modification is thought to play a crucial mechanistic role in the highly coordinated pattern of collinear Hox gene expression, we examined the maintenance of the spatial collinear expression pattern of Hoxc genes and the corresponding histone modifications during embryogenesis and in early postnatal mice. Hox expression patterns and histone modifications were analyzed by semi-quantitative RT-PCR and chromatin immunoprecipitation (ChIP)-PCR analyses, respectively. The spatiotemporal expression patterns of Hoxc genes in a cluster were maintained until the early postnatal stage (from E8.5 through P5). Examination of histone modifications in E14.5 and P5 tissues revealed that level of H3K27me3 is only a weak correlation with collinear Hoxc gene expression in the trunk regions although diminished in general, however the enrichment of H3K4me3 is strongly correlated with the gene expression in both stages. In summary, the initial spatiotemporal collinear expression pattern of Hoxc genes and epigenetic modifications are maintained after birth, likely contributing to the establishment of the gene expression code for position in the anatomic body axis throughout the entire life of the organism.
International journal of biological sciences 01/2013; 9(9):960-5. · 3.17 Impact Factor
[show abstract][hide abstract] ABSTRACT: Over the past several years, the incidence of hepatitis A infection has been increasing rapidly in the young-adult population in Korea. We examined the effects of area-level socioeconomic status and environmental hygiene on the incidence of hepatitis A.
This study is based on the registered national population of Korea and the national health insurance data from 2004 to 2008. A total of 73 459 individuals were confirmed to have had hepatitis A. The standardized incidences of hepatitis A in 232 districts adjusted for sex and age of people were calculated for each year, and the rate ratios of the incidence rates were estimated according to area-level socioeconomic status and environmental hygiene using multiple Poisson regression models.
The incidence rates of hepatitis A infection were 15.6 (per 100 000) in 2004, 19.0 (per 100 000) in 2005, 27.2 (per 100 000) in 2006, 25.1 (per 100 000) in 2007, and 61.7 (per 100 000) in 2008. The analysis of the area-level effects showed that residential areas of the less deprived than other regions, areas with higher levels of education, and heavily populated areas were significantly associated with increased risk.
There is a very strong possibility that both area-level socioeconomic status and environmental hygiene play a role in increasing the risk of hepatitis A infection in Korea. Therefore, to reduce hepatitis A infection, we need a nationwide strategy that considers these area-level characteristics.
Journal of preventive medicine and public health = Yebang Ŭihakhoe chi. 05/2012; 45(3):164-73.
[show abstract][hide abstract] ABSTRACT: Busan is reported to have the highest mortality rate among 16 provinces in Korea, as well as considerable health inequality across its districts. This study sought to examine overall and cause-specific mortality and deprivation at the town level in Busan, thereby identifying towns and causes of deaths to be targeted for improving overall health and alleviating health inequality.
Standardized mortality ratios (SMRs) for all-cause and four specific leading causes of death were calculated at the town level in Busan for the years 2005 through 2008. To construct a deprivation index, principal components and factor analysis were adopted, using 10% sample data from the 2005 census. Geographic information system (GIS) mapping techniques were applied to compare spatial distributions between the deprivation index and SMRs. We fitted the Gaussian conditional autoregressive model (CAR) to estimate the relative risks of mortality by deprivation level, controlling for both the heterogeneity effect and spatial autocorrelation.
The SMRs of towns in Busan averaged 100.3, ranging from 70.7 to 139.8. In old inner cities and towns reclaimed for replaced households, the deprivation index and SMRs were relatively high. CAR modeling showed that gaps in SMRs for heart disease, cerebrovascular disease, and physical injury were particularly high.
Our findings indicate that more deprived towns are likely to have higher mortality, in particular from cardiovascular disease and physical injury. To improve overall health status and address health inequality, such deprived towns should be targeted.
Journal of preventive medicine and public health = Yebang Ŭihakhoe chi. 11/2011; 44(6):242-8.
[show abstract][hide abstract] ABSTRACT: The aim of the present study was to compare the validity of the International Study of Asthma and Allergies in Childhood (ISAAC) written (WQ) and audiovisual questionnaires (AVQ 3.0) in two age-groups (10-12 and 13-15 years, respectively).
The 13-15 year olds performed the self-completed the WQ and AVQ on the same day. The 10-12 year olds performed the self-completed the AVQ and the parent-completed WQ was completed by their parents. The methacholine challenge test was conducted in 10-12 year olds from one elementary school.
In 10-12 year olds, the AVQ detected a generally higher prevalence of asthma symptoms than WQ. In 13-15 year olds, this was reversed. In 10-12 year olds, poor agreement was found between the parent-completed WQ and the self-reported AVQ. In 13-15 year olds, moderate agreement was found between the self-reported WQ and AVQ. Low sensitivity was found, in predicting bronchial hyper-responsiveness (BHR) for all questions of both WQ and AVQ in 10-12 year olds. However, the AVQ had slightly higher sensitivity than WQ, with the exception of wheeze ever, although it was not statistically significant.
The ISAAC AVQ may be another effective instrument for assessing the prevalence of asthma symptoms in children aged 10-12 years, whereas the parent-reported-WQ may underestimate the prevalence of asthma symptoms in this age-group.
[show abstract][hide abstract] ABSTRACT: Hoxc8 has multiple roles in normal skeletal development. In this paper, a MC3T3-E1 subclone 4 osteogenic cell differentiation model was used to examine expression of Hoxc8 at multiple stages of osteogenesis. We found that Hoxc8 expression levels do not change in the early stage but increase in the middle stage and decrease in the late stage of osteogenesis. A knockdown of Hoxc8 by small-interfering RNA transfection in C2C12 cells indicated that Hoxc8 is a negative regulator of osteogenesis. Similarly, expression of Hoxc8 in C2C12 cells decreases alkaline phosphatase levels induced by bone morphogenetic protein-2 (BMP-2). The results of this study showed that Hoxc8 is involved in BMP-2-induced osteogenesis, and osteoblast differentiation in vitro is negatively regulated by Hoxc8, suggesting that Hoxc8 regulation is essential for osteoblast differentiation.
Applied biochemistry and biotechnology 03/2009; 160(3):891-900. · 1.94 Impact Factor
[show abstract][hide abstract] ABSTRACT: Adipose-derived stem cells (ADSCs) have been shown to induce wound-healing effects. Because inflammation near the wound area induces oxygen deficiency, it is interesting to elucidate the effect of hypoxia on the function of ADSCs. In this work, we asked: (1) does hypoxia alter the wound-healing function of ADSCs? and (2) what are the major factors responsible for the alteration in the wound-healing function? Effect of hypoxia on the proliferation of ADSCs was first examined that hypoxia (2% O(2)) enhanced the proliferation of ADSCs in either the presence of serum or in the absence of serum. The conditioned medium of ADSCs harvested under hypoxia (hypoCM) significantly promoted collagen synthesis and the migration of human dermal fibroblasts, compared with that in normoxia (norCM). In the animal studies, hypoCM significantly reduced the wound area compared with norCM. Furthermore, mRNA and protein measurements showed that hypoxia up-regulated growth factors such as vascular endothelial growth factor (VEGF) and basic fibroblast growth factor (bFGF). Inhibition of VEGF and bFGF using neutralizing antibodies reversed the migration of the wounded human dermal fibroblasts and the healing of wounds in animal experiment. Collectively, these results suggest that hypoxia increases the proliferation of ADSCs and enhances the wound-healing function of ADSCs, at least partly, by up-regulating the secretion of VEGF and bFGF.
Wound Repair and Regeneration 01/2009; 17(4):540-7. · 2.76 Impact Factor
[show abstract][hide abstract] ABSTRACT: Protein transduction domains (PTDs) have been shown to cross the biological cell membranes efficiently through a receptor and energy independent mechanism. Because of its ease in membrane transducing ability, PTDs could be used as a gene delivery vector. Since we already have shown that purified Hoxc8 homeoprotein has the ability to cross the cellular membrane, we analyzed the possibility of the third helix of the Hoxc8 homeodomain as a useful gene delivery vector. For that purpose, a 16-aa long synthetic oligopeptide Hoxc8 Protein Transduction Domain (HPTD) was chemically synthesized and then tested to see whether the HPTD could form a complex with DNA or not. Gel retardation analysis revealed that the HPTD interacts with plasmid DNA efficiently but failed to transfer the DNA into the cells. However, HPTD can enhance the efficiency of gene transfer in combination with Lipofectamine which doubled the gene transfer rate into COS-7 cells compared with the DNA/Lipofectamine control. An MTT assay indicated that the amount of HPTD used in the complex for the transfection did not show any cytotoxicty in COS-7 cells. The TEM studies showed compact particle formation in the presence of HPTD. These results indicate that the HPTD could be a good candidate adjuvant molecule to enhance the gene transfer efficiency of Lipofectamine in eukaryotic cells.
[show abstract][hide abstract] ABSTRACT: Osteoporosis is a major public health problem in both Western and Asian populations. Because the aged population in Korea is increasing, the number of osteoporotic fractures is thought to be also increasing. However, there has been no nationwide analysis of osteoporotic fractures in Korea. We analyzed the incidence and cost of hip fracture from 2001 to 2004 by using data from the Health Insurance Review Agency, Korea. In the over 50 years age group, the number of hip fractures in women increased from 250.9/100,000 persons in 2001 to 262.8/100,000 in 2004, a 4.7% increase. However, that in men decreased from 162.8/100,000 in 2001 to 137.5/100,000 in 2004, a 15.5% decrease. Direct medical care costs of hip fracture increased from $62,707,697 in 2001 to $65,200,035 in 2004, and the proportional cost of hip fractures in the national medical costs increased by 4.5% over 4 years (from 0.200% in 2001 to 0.209% in 2004). On analysis of the population-based data obtained from the whole country from 2001 to 2004, the incidence rate of hip fractures in women, not in men, and its cost have increased in Korea. The gender distribution of hip fractures underlines the need for aggressive intervention in osteoporosis in elderly women.
Journal of Bone and Mineral Metabolism 02/2008; 26(4):400-5. · 2.22 Impact Factor
[show abstract][hide abstract] ABSTRACT: To examine the effect of lengthened immobilization on the expression of genes and concomitant morphological changes in soleus muscle, rat hindlimbs were immobilized at the ankle in full dorsiflexion by plaster cast. After removing the muscle (after 1 hr, 1, 4, and 7 days of immobilization), morphology and differential gene expression were analyzed through electron microscopy and differential display reverse transcription-polymerase chain reaction (DDRT-PCR), respectively. At the myotendinous junction (MTJ), a large cytoplasmic space appeared after 1 hr of immobilization and became enlarged over time, together with damaged Z lines. Interfibrillar space was detected after 1 day of immobilization, but diminished after 7 days. At the muscle belly, Z-line streaming and widening were observed following 1 hr of immobilization. Disorganization of myofilaments (misalignment of adjacent sarcomeres, distortion, or absence of Z lines) was detected after 4 days. Furthermore, mitochondrial swelling and cristae disruption were observed after 1 day of stretching. A set of 15 differentially expressed candidate genes was identified through DDRT-PCR. Of 11 known genes, seven (Atp5g3, TOM22, INrf2, Slc25a4, Hdac6, Tpm1, and Sv2b) were up and three (Podxl, Myh1, and Surf1) were down-regulated following immobilization. In the case of Acyp2, 1-day stretching-specific expression was observed. Atp5g3, Slc25a4, TOM22, and Surf1 are mitochondrial proteins related to energy metabolism, except TOM22, which has a chaperone-like activity located in the mitochondrial outer membrane. Together with these, INrf2, Hdac6, Podxl, and Acyp2 are related more or less to stress-induced apoptosis, indicating the responses to apoptotic changes in mitochondria caused by stretching. The expression of both Tpm1 and Myh1, fast twitch isoforms, suggests adaption to the immobilization. These results altogether indicate that lengthened immobilization regulates the expression of several stress/apoptosis-related and muscle-specific genes responsible for the slow-to-fast transition in soleus muscle despite profound muscle atrophy.