Effects of 1,25-dihydroxyvitamin D₃ on the differentiation of MC3T3-E1 osteoblast-like cells

PURPOSE: The purpose of this study was to evaluate the effects of 1,25-dihydroxyvitamin D₃ on the proliferation, differentiation, and matrix mineralization of MC3T3-E1 osteoblast-like cells in vitro. METHODS: MC3T3-E1 osteoblastic cells and 1,25-dihydroxyvitamin D₃ were prepared. Cytotoxic effects and osteogenic differentiation were evaluated using the 3-(4,5-dimethylthiazol-2-yl)-2,5-diphenyltetrazolium bromide (MTT) assay, alkaline phosphatase (ALP) activity assay, ALP staining, alizarin red S staining, and reverse transcription-polymerase chain reaction (RT-PCR) for osteogenic differentiation markers such as ALP, collagen type I (Col-I), osteocalcin (OCN), vitamin D receptor (VDR), and glyceraldehyde 3-phosphate dehydrogenase. RESULTS: The MTT assay showed that 1,25-dihydroxyvitamin D₃ did not inhibit cell growth and that the rate of cell proliferation was higher than in the positive control group at all concentrations. ALP activity was also higher than in the positive control group at low concentrations of 1,25-dihydroxyvitamin D₃ (10−10, 10−12, and 10−14 M). RT-PCR showed that the gene expression levels of ALP, Col-I, OCN, and vitamin D receptor (VDR) were higher at a low concentration of 1,25-dihydroxyvitamin D₃ (10−12 M). Alizarin red S staining after treatment with 1,25-dihydroxyvitamin D₃ (10−12 M) showed no significant differences in the overall degree of calcification. In contrast to the positive control group, formation of bone nodules was induced in the early stages of cell differentiation. CONCLUSIONS: We suggest that 1,25-dihydroxyvitamin D₃ positively affects cell differentiation and matrix mineralization. Therefore, it may function as a stimulating factor in osteoblastic bone formation and can be used as an additive in bone regeneration treatment.

The association between radiographic embrasure morphology and interdental papilla reconstruction using injectable hyaluronic acid gel

PURPOSE: The purpose of this study was to evaluate the clinical efficacy of enhancing deficient interdental papilla with hyaluronic acid gel injection by assessing the radiographic anatomical factors affecting the reconstruction of the interdental papilla. METHODS: Fifty-seven treated sites from 13 patients (6 males and 7 females) were included. Patients had papillary deficiency in the upper anterior area. Prior to treatment, photographic and periapical radiographic standardization devices were designed for each patient. A 30-gauge needle was used with an injection-assistance device to inject a hyaluronic acid gel to the involved papilla. This treatment was repeated up to 5 times every 3 weeks. Patients were followed up for 6 months after the initial gel application. Clinical photographic measurements of the black triangle area (BTA), height (BTH), and width (BTW) and periapical radiographic measurements of the contact point and the bone crest (CP-BC) and the interproximal distance between roots (IDR) were undertaken using computer software. The interdental papilla reconstruction rate (IPRR) was calculated to determine the percentage change of BTA between the initial and final examination and the association between radiographic factors and the reconstruction of the interdental papilla by means of injectable hyaluronic acid gel were evaluated. RESULTS: All sites showed improvement between treatment examinations. Thirty-six sites had complete interdental papilla reconstruction and 21 sites showed improvement ranging from 19% to 96%. The CP-BC correlated with the IPRR. More specifically, when the CP-BC reached 6 mm, virtually complete interdental papilla reconstruction via injectable hyaluronic acid gel was achieved. CONCLUSIONS: These results suggest that the CP-BC is closely related to the efficacy of hyaluronic acid gel injection for interdental papilla reconstruction.

Shortage in residents of internal medicine and current status of Korean medical system

The shortage of internal medicine residents depict the contradictions and perversions in Korean medical system. Internal medicine is the foundation of medicine and the fact it serves as the most essential medical services for the people adds severe gravity to the issue. The fundamental problem derives from the contradictions in health insurance system. In fact, the poor medical fee and the failure of medical delivery system are the core drawbacks to the current crisis. Unless above matters are addressed to draw a constructive resolution, it is an undeniable fact that this may become a serious threat to the national health system and people's wellbeing.

The process by which new health technology is listed for insurance coverage

Whether or not insurance covers new health technology has a great effect on the extent of its acceptance and diffusion. Thus many stakeholders vie to participate in determining insurance reimbursement regulations. This paper explains the process by which new health care technology is added to the coverage list in the Republic of Korea,with each checkpoint explained. Our paper also argues that the implication of the listing process of Korean insurance coverage should be modified in the area such as what is the principle of insurance coverage and who will decide the acceptance criteria of health technology, safety, effectiveness, economic feasibility, and relative value.