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Intensive morphometric analysis of enormous alterations in skeletal bone system with micro-CT for AHNAK−/− mice

2020 , Kim, I.Y. , Yi, S.S. , Shin, J.H. , Kim, Y.N. , Ko, C.-Y. , Kim, H.S. , Lee, S.Y. , Bae, Y.S. , Seong, J.K.

AHNAK has been reported to be involved in actin cytoskeleton rearrangement of some cell types, calcium homeostasis, and activation of T cells. Although the functional role of AHNAK in muscle cells, epidermis, and brain has been determined, its association with apparent clinical impairment has not been found yet. During phenotypic analysis of AHNAK knock out (KO) mice for many years, we observed that AHNAK KO mice showed very slow growth. Snouts of these animals were very short, and their bones were easily broken compared to normal mice. It is known that AHNAK is closely related to calcium. However, intensive morphological studies on phenotypes of bone have yet been reported for AHNAK. Thus, the objective of the present study was to analyze the morphology of skull, mandibular, limbs, and caudal bones of AHNAK KO mice intensively using micro-CT with many factors for various ages of these mice (6 weeks, 18 weeks, and 40 weeks). As a result, it was found that the facial region of AHNAK KO mouse showed a large difference in mandible than skull. Their both femur and tibia were shortened, and bone strength was also significantly decreased compared to normal mice. Particularly, the tail bone of AHNAK KO mice exhibited morphological abnormality by age. Taken together, these results suggest that AHNAK plays an important role in bone shape, development, and metabolism. Although our results demonstrated that AHNAK has a distinct role in bone, further investigations are needed to determine various features of bone metabolism related to AHNAK in the future.

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Effect of stool height on slumped posture during push-and-pull weeding motion

2015 , Cho, Y.K. , Myeong, S.-S. , Cho, S. , Kim, H.S.

Purpose: The excessive accumulation of work burden is one of the main factors underlying musculoskeletal disorders in the farming population. The present study was carried out to determine the joint torques and muscle contractions of the lower body in relation to slumped postures with or without a stool during push-and-pull weeding motions. Methods: Using data from a 3D motion analysis system, a 3D virtual human body model was created consisting of 19 segments and 59 muscles. Among these, the lower body joints (ankle, knee, hip, and lumbar) and muscles (tibialis anterior, gastrocnemius, biceps femoris, and erector spinae) were analyzed for four cases of slumped postures: without a stool and with stools of various heights (10, 15, and 20 cm). Results: The flexion of the lumbar joint was presented during push-and-pull weeding motions without a stool. However, the extension of the lumbar joint was presented during pushand-pull weeding motions with a stool. The ranges of th e joint torques did not change in a meaningful way between the results for the cases without a stool and with a stool. In addition, the results according to the stool height did not present meaningful outcomes associated with the angle change in the joints. Conclusions: Irrespective of the height, a stool may provide support for slumped postures involving the lumbar joint and erector spinae.

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Antiangiogenic Activity of Acer tegmentosum Maxim Water Extract in Vitro and in Vivo

2015 , Kim, E.C. , Kim, S.H. , Piao, S.J. , Kim, T.J. , Bae, K. , Kim, H.S. , Hong, S.S. , Lee, B.I. , Nam, M.

Angiogenesis, the formation of new blood vessels, is critical for tumor growth and metastasis. Notably, tumors themselves can lead to angiogenesis by inducing vascular endothelial growth factor (VEGF), which is one of the most potent angiogenic factors. Inhibition of angiogenesis is currently perceived as one of the most promising strategies for the blockage of tumor growth. In this study, we investigated the effects of Acer tegmentosum maxim water extract (ATME) on angiogenesis and its underlying signal mechanism. We studied the antiangiogenic activity of ATME by using human umbilical vein endothelial cells (HUVECs). ATME strongly inhibited VEGF-induced endothelial cell proliferation, migration, invasion, and tube formation, as well as vessel sprouting in a rat aortic ring sprouting assay. Moreover, we found that the p44/42 mitogen activated protein (MAP) kinase signaling pathway is involved in the inhibition of angiogenesis by ATME. Moreover, when we performed the in vivo matrigel plug assay, VEGF-induced angiogenesis was potently reduced when compared to that for the control group. Taken together, these results suggest that ATME exhibits potent antiangiogenic activity in vivo and in vitro and that these effects are regulated by the extracellular regulated kinase (ERK) pathway.

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Deterioration of trabecular bone microarchitecture in the lumbar vertebrae in growing male mice following sciatic neurectomy

2014 , Ko, C.Y. , Jung, Y.J. , Seo, D.H. , Lee, S.D. , Kim, H.S.

Sciatic nerve injury (SNI) can lead to significant bone loss in the lower extremities. However, the effects of SNI on the lumbar vertebrae are controversial. The present study aimed to evaluate the longitudinal effects of SNI on the lumbar vertebrae. Twenty-four 12-week-old male C57BL/6 mice (24.55 +/- 0.17 g) were randomly assigned to 3 groups (8 mice each) and underwent unilateral sciatic neurectomy (USN group), bilateral sciatic neurectomy (BSN group), or no surgery (CON group). The third (L3) and fourth (L4) lumbar vertebrae were scanned by in-vivo micro-computed tomography (Anot signCT) preoperatively and at 14 and 28 days postoperatively. Using mu CT images, structural parameters and bone mineralization density distribution of the trabecular bone were analyzed among the 3 groups. In the BSN group, structural and material properties of L3 and L4 worsened after 14 days. Deterioration in the structural properties of L3 was observed at 28 days in the USN group, whereas no changes were observed in L4. These results implied that SNI can cause considerable deterioration in the microarchitecture of trabecular bone in the lumbar vertebrae. However, differences in the magnitude and rate of the deterioration and its onset period are observed between cases of unilateral and bilateral SNI.

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Data of intracellular insulin protein reduced by autophagy in INS-1E cells

2016 , Kim, H.S. , Yoo, Y.-M.

Autophagy appears to be involved in maintaining normal intracellular insulin content by accelerating the insulin degradation rate in β-cells (Marsh et al., 2007) [1]. 2-deoxy-d-glucose (2-DG) is metabolized by hexokinase, and acts as an inhibitor of glycolysis. 2-DG triggers glucose deprivation without altering other nutrients or metabolic pathways (Aghaee et al., 2012) [2], and appears to be an ideal tool for studying autophagy. Rapamycin induced upregulation of autophagy in both cultured isolated islets and pancreatic β-cells (Tanemura et al., 2012) [3]. Here, we examined that 2-DG or rapamycin-induced autophagy may decrease the production of intracellular insulin in INS-1E insulinoma cells. Data showed that autophagy was increased by 2-DG or rapamycin by Western blotting and Immunofluorescence staining analyses. Also, intracellular insulin decreased by 2-DG or rapamycin. Furthermore, the autophagy inhibitors, bafilomycin A1 and/or 3-methyladenine, in the presence o r absence of 2-DG or rapamycin increased intracellular insulin in INS-1E insulinoma cells.

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Decreased bone volume and bone mineral density in the tibial trabecular bone is associated with Per2 gene by 405 nm laser stimulation

2015 , Yoo, Y.-M. , Lee, M.-H. , Park, J.H. , Seo, D.-H. , Lee, S. , Jung, B. , Kim, H.S. , Bae, K.

Low-level laser therapy/treatment (LLLT) using a minimally invasive laser needle system (MILNS) might enhance bone formation and suppress bone resorption. In this study, the use of 405 nm LLLT led to decreases in bone volume and bone mineral density (BMD) of tibial trabecular bone in wild-type (WT) and Per2 knockout (KO) mice. Bone volume and bone mineral density of tibial trabecular bone was decreased by 405 nm LLLT in Per2 KO compared to WT mice at two and four weeks. To determine the reduction in tibial bone, mRNA expressions of alkaline phosphatase (ALP) and Per2 were investigated at four weeks after 405 nm laser stimulation using MILNS. ALP gene expression was significantly reduced in the LLLT-stimulated right tibial bone of WT and Per2 KO mice compared to the non-irradiated left tibia (p < 0.001). Per2 mRNA expression in WT mice was significantly reduced in the LLLT-stimulated right tibial bone compared to the non-irradiated left tibia (p < 0.001). To identify the decrease in tibial bone mediated by the Per2 gene, levels of runt-related transcription factor 2 (Runx2) and ALP mRNAs were determined in non-irradiated WT and Per2 KO mice. These results demonstrated significant downregulation of Runx2 and ALPmRNA levels in Per2 KO mice (p < 0.001). Therefore, the reduction in tibial trabecular bone resulting from 405 nm LLLT using MILNS might be associated with Per2 gene expression.

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Enhancement of bone quality and longitudinal growth due to free-fall motion in growing rats

2015 , Cho, S. , Eom, S. , Seo, D.-H. , Park, J. , Ko, C.-Y. , Kim, H.S.

Objectives: This study is to investigate the synchronous phenomena between bone quality and longitudinal length in a same subject affected by landing exercise. Physical exercise on the ground induces external loading to human body due to resistance from ground which can activate bone generation or remodeling. Especially, when the impact stimulation is applied to bone, it may improve bone quality and lengthening. Methods: 6-week-old male Wistar rats were randomly allocated to one of two conditions: free fall from 40 cm-height (I40; n = 7), and control (IC; n = 7). The impact stimulations were administered to the free fall groups, 10 times/day, and 5 days/week for 8 weeks. Structural parameters and longitudinal length of tibia were measured to quantitatively evaluate the variation in morphological characteristics and bone length with maturing. Results: The landing impact seems to be commonly effective on the enhancement of bone quality as well as longitudinal growth. Howe ver, the extent of enhancement may be more dominant in bone quality than longitudinal growth. On the other hand, the ratio of longitudinal growth seems to be dependent on the duration of stimuli whereas the enhancement of bone quality does not. Conclusions: This study verified that free-falls exercise can be effective on the enhancement of bone qualities and promotion of vertical growth in long bones. We expect that it might be possible for the moderate impact stimulation to be proposed as an aid for prevention of bone loss and promotion of bone lengthening. © 2015, Korean Society of Medical and Biological Engineering and Springer.

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Effectiveness of micro-current electrical stimulation for treating rheumatoid arthritis

2016 , Kim, S.H. , Lee, H. , Hwang, D.H. , Seo, D.H. , Kim, H.S. , Cho, S.

Induction of micro-current in subject is known to be effective on the treatment of inflammatory disease. Thus, this study evaluated that the micro-current electrical treatment (MET) can reduce rheumatoid arthritis (RA), which is one of inflammatory disease, and tried to find optimized level of current for treatment. 55 male 11-week-old C57BL/6 mice were used and randomly allocated into five groups; normal group (N; n=11), the group of induced RA (C; n=11) and three groups of induced RA with MET (M) using different levels of current by 22 mA, 50 mA, and 400 mA (22M, 50M and 400M; n=11, respectively). MET was carried out for 1 hour each day. Both 3rd metatarsal (3rd MT) and tarsal (T) were scanned by in-vivo micro computed tomography (micro-CT) at 0week and after 3weeks in order to obtain structural parameters including BMD (Bone mineral density), BV (Bone volume) and Obj.N (Mean number of objects per slice). In M groups, all the measured parameters after 3 weeks were significantly higher than those of C group regardless of the current levels. However, there is no significant difference among the different levels of electrical current at 3week. These results indicated that the MET may be effective on the treatment of RA. However, we cannot assure the optimized level of current to treat RA tremendously.

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Special issue on biomechanics

2015 , Kim, H.S. , Cho, S.

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Comparative study of hydroxyapatite prepared from seashells and eggshells as a bone graft material

2014 , Lee, S.-W. , Balázsi, C. , Balázsi, K. , Seo, D.-H. , Kim, H.S. , Kim, C.-H. , Kim, S.-G.

The aims of this study were to determine the physical properties of hydroxyapatite from seashells (sHA) and from eggshells (eHA), to analyze elements within sHA and eHA, and to compare the bone regeneration ability between sHA and eHA in a rat parietal bone defect model. The sHA and eHA particles had a similar morphology in scanning electron microscope images. From the Fourier-transform infrared absorbance spectra and X-ray diffraction results, both types of hydroxyapatite (HA) had the characteristics of pure HA. Inductively coupled plasma atomic emission spectroscopy results suggested that the sHA had higher levels of sodium and strontium than the eHA, whereas the eHA had higher levels of magnesium than the sHA. In -CT results, the mean bone mineral density of the sHA was significantly higher than the control at 4 weeks after the operation (p = 0.012). The mean bone volume of the eHA was significantly higher than the control at 8 weeks after the operation (p = 0.012). In the histological images at 4 weeks after the operation, foreign body multinucleated giant cells were observed around the agglomerated sHA particles, while there were fewer inflammatory reactions around the agglomerated eHA particles. The eHA group showed better results in bone formation than did the sHA group in this study.