• Maxillofacial Plastic and Reconstructive Surgery
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• v.30 no.1
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• pp.60-71
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• 2008

The objective of this study is to evaluate the stress distribution according to the thread design and the marginal bone loss of a single unit dental implant under the axial and offset-axial loading by three dimensional finite element analysis. The implants used had the diameter of 5mm and 4mm with 13mm in length and prosthesis with a conical type which is 6mm in height and 12mm in diameter. The thread designs were triangular, square and buttress. In the three dimensional finite element model with $15\times15\times20mm$ hexahedron and 2mm cortical thickness, implants were placed with crown to root ratio 7:12, 10:9, 13:6 and 16:3. And additionally the axial force of 100N were applied into 0mm, 2mm and 4mm away from the center of the implants. The results were as follows 1. The maximum von-Mises stress in cortical bone was concentrated to cervical area of implant, and in cancellous bone, apical portion. 2. Comparing the von-Mises stresses in cortical bone of 2mm and 4mm offset loading with central axial loading, it were increased to 3 and 5 times in diameter 4mm implant, and 2 and 4 times, in diameter 5mm implant. 3. The square threads were more effective than the triangular and butress as the longer diameter, the offset loading, and the worse crown to root ratio. 4. The von-Mises stresses were relatively stable until crown to root ratio 13:6, but it was suddenly increased at 16:3. From the results of this study, minimum requirement of crown to root ratio of implant is 2:1, and in the respect of crown to root ratio, diameter and offset loading, square threads are more effective than triangular and buttress threads.

• Korean Journal of Pharmacognosy
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• v.38 no.2 s.149
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• pp.101-107
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• 2007

This study was carried out to examine the in vitro effects of alginate (LVA) which is low viscosity alginic acid, on collagen type II synthesis of chondrocytes and the in vivo effect, orally administered, on cartilage degradation. Rabbit articular chondrocytes were cultured in 35 mm dishes and then LVA was treated. The effects of LVA of various viscosity (86.5 cP(LVA1),45.4 cP(LVA2), 21.2 cP(LVA3) and 9.6 cP(LVA4)) and various concentration (50, 100, 200 ${\mu}$g/ml of LVA4) on chondrocytes were determined by western blotting assay for the detection of collagen type II production. In western blotting assay, collagen type II production in chondrocytes were 1.00 in control,0.95 in LVA1, 1.41 in LVA2, 1.57 in LVA3 and 1.58 in LVA4. Collagen type II production of various concentration of LVA4 were 1.00 in control, 1.24 in 50 ${\mu}$g/ml of LVA4, 1.52 in 100 ${\mu}$g/ml of LVA4 and 1.86 in 200 ${\mu}$g/ml of LVA4. Osteoarthritis (OA) was induced in 24 rabbits by unilateral anterior cruciate ligament transection (ACLT) and randomly divided into 6 groups. The experimental group was given oral administration of 0.5 ml/kg of saline(control), 12.5 mg/kg of LVA (A12.5), 25 mg/kg of LVA (A25), 50 mg/kg of LVA (A5O), 75 mg/kg of LVA (A75) and 20 mg/kg of aceclofenac (AC) for 6 weeks after ACLT. All knees were harvested at 6 weeks after surgery and cartilage degradation was evaluated. Cartilage degradation in the control group was significantly more severe than that in the A25, A5O and A75 groups but AC group had no significant changes on the macroscopic grading scale.

• Journal of Nutrition and Health
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• v.44 no.3
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• pp.196-202
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• 2011

Epigallocatechin gallate (EGCG), or epigallocatechin 3-gallate, is the ester of epigallocatechin and gallic acid, and is a type of catechin. EGCG may be therapeutic for many disorders including diabetics and some types of cancer. However it is unknown whether EGCG can induce transdifferentiation of pancreatic cells in pancreatitis. The aim of this study was to investigate the effects of EGCG on the expression of pancreatic regenerating related markers in pancreatic AR42J cells, a model of pancreatic progenitor cells. AR42J cells, differentiated with betacellulin and activin A, were cultured with/without EGCG in a time-dependent manner. Cell growth rate, levels of mRNA, and protein expression were examined with the MTT assay, quantitative PCR, and Western blots, respectively. The results showed that AR42J cell growth rates were inhibited by EGCG in a dose-dependent manner. mRNA and protein expression of amylase, insulin and neurogenin 3 (ngn 3) increased in AR42J cells treated with EGCG. Additionally, we demonstrated that the signal transduction pathway of mitogen-activated protein (MAP) kinase is active in EGCG-treated AR42J cells. ERK and JNK phosphorylation decreased in cells treated with EGCG but not p38 phosphorylation. Activation of the p38 MAP kinase pathway was confirmed by specific MAP kinase pathways inhibitors: U0126 for ERK, SP600126 for JNK, and SB203580 for p38. Activated p38 phosphorylation was inhibited by the specific p38 inhibitor SB203580 but p38 phosphorylation was inhibited with increased EGCG treatment. The ERK and JNK MAP kinase pathways were not affected by EGCG treatment. Although further studies are needed, these results suggest that EGCG affects the induction of pancreatic cell regeneration by increasing the ngn 3 protein and mRNA expression and activating the p38 MAP kinase pathway.

• Asian Pacific Journal of Cancer Prevention
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• v.17 no.2
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• pp.775-779
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• 2016

Background: The current study examined the effectiveness of concurrent therapy using photodynamic therapy (PDT) and clofibric acid (CA) to treat peritoneal carcinomatosis resulting from ovarian cancer. Materials and Methods: Nude rats were used to create a model of peritoneal carcinomatosis resulting from ovarian cancer and the effectiveness of PDT with 5-aminolevulinic acid methyl ester hydrochloride (methyl-ALA-PDT) was determined. The survival time of rats receiving that therapy was compared to the survival time of a control group. Rats with peritoneal carcinomatosis resulting from ovarian cancer were divided into 3 groups: a group that received debulking surgery (DS) alone, a group that received DS+methyl-ALA-PDT, and a group that received DS+methyl-ALA-PDT+CA. The survival time of the 3 groups was compared. Protoporphyrin, a metabolite of methyl-ALA, produces a photochemical action when activated by light. The level of protoporphyrin (the concentration) that reached organs in the abdomen was measured with HPLC. Results: Rats receiving methyl-ALA-PDT had a significantly longer survival time compared to the controls. Rats with peritoneal carcinomatosis that received DS+methyl-ALA-PDT+CA had a significantly longer survival time compared to the rats that received DS alone. Some of the rats that received concurrent therapy survived for a prolonged period. Protoporphyrin was highly concentrated in peritoneal metastases, but only small amounts reached major organs in the abdomen. PDT was not found to result in necrosis in the intestines. Conclusions: The results indicated that concurrent therapy consisting of PDT with methyl-ALA and CA is effective at treating peritoneal carcinomatosis resulting from ovarian cancer without damaging organs.

• Asian Pacific Journal of Cancer Prevention
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• v.16 no.6
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• pp.2419-2423
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• 2015

Background: There are few choices for treatment of advanced cancer patients who do not respond to or tolerate conventional anti-cancer treatments. Therefore this study aimed to deploy the benefits and clinical efficacy of continuous dendritic cell-cytokine induced killer cell infusions in such patients. Materials and Methods: A total of 381 infusions (from 67 advanced cases recruited) were included in this study. All patients underwent peripheral blood mononuclear cell apheresis for the following cellular therapy and dendritic cells-cytokine induced killer cells were expanded in vitro. Peripheral blood T lymphocyte subsets were quantified through flow cytometry to address the cellular immunity status. Clinical efficacy and physical activities were evaluated by RECIST criteria and Eastern Cooperative Oncology Group scores respectively. Logistic regression model was used to estimate the association between cellular infusions and clinical benefits. Results: An average of $5.7{\pm}2.94{\times}10^9$ induced cells were infused each time and patients were exposed to 6 infusions. Cellular immunity was improved in that cytotoxic $CD8^+CD28^+$ T lymphocytes were increased by 74% and suppressive $CD8^+CD28^-$ T lymphocytes were elevated by 16% (p<0.05). Continuous infusion of dendritic cells-cytokine induced killer cells was associated with improvement of both patient status and cellular immunity. A median of six infusions were capable of reducing risk of progression by 70% (95%CI 0.10-0.91). Every elevation of one ECOG score corresponded to a 3.90-fold higher progression risk (p<0.05) and 1% increase of $CD8^+CD28^-$ T cell proportion reflecting a 5% higher risk of progression (p<0.05). Conclusions: In advanced cancer patients, continuous dendritic cell-cytokine induced killer cell infusions are capable of recovering cellular immunity, improving patient status and quality of life in those who are unresponsive to conventional cancer treatment.

• The Korean Journal of Physiology and Pharmacology
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• v.17 no.1
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• pp.99-109
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• 2013

The aim of this study was to determine whether fimasartan, a newly developed $AT_1$ receptor blocker, can affect the CA release in the isolated perfused model of the adrenal medulla of spontaneously hypertensive rats (SHRs). Fimasartan (5~50 ${\mu}M$) perfused into an adrenal vein for 90 min produced dose- and time-dependently inhibited the CA secretory responses evoked by ACh (5.32 mM), high $K^+$ (56 mM, a direct membrane depolarizer), DMPP (100 ${\mu}M$) and McN-A-343 (100 ${\mu}M$). Fimasartan failed to affect basal CA output. Furthermore, in adrenal glands loaded with fimasartan (15 ${\mu}M$), the CA secretory responses evoked by Bay-K-8644 (10 ${\mu}M$, an activator of L-type $Ca^{2+}$ channels), cyclopiazonic acid (10 ${\mu}M$, an inhibitor of cytoplasmic $Ca^{2+}$-ATPase), and veratridine (100 ${\mu}M$, an activator of $Na^+$ channels) as well as by angiotensin II (Ang II, 100 nM), were markedly inhibited. In simultaneous presence of fimasartan (15 ${\mu}M$) and L-NAME (30 ${\mu}M$, an inhibitor of NO synthase), the CA secretory responses evoked by ACh, high $K^+$, DMPP, Ang II, Bay-K-8644, and veratridine was not affected in comparison of data obtained from treatment with fimasartan (15 ${\mu}M$) alone. Also there was no difference in NO release between before and after treatment with fimasartan (15 ${\mu}M$). Collectively, these experimental results suggest that fimasartan inhibits the CA secretion evoked by Ang II, and cholinergic stimulation (both nicotininc and muscarinic receptors) as well as by membrane depolarization from the rat adrenal medulla. It seems that this inhibitory effect of fimasartan may be mediated by blocking the influx of both $Na^+$ and $Ca^{2+}$ through their ion channels into the rat adrenomedullary chromaffin cells as well as by inhibiting the $Ca^{2+}$ release from the cytoplasmic calcium store, which is relevant to $AT_1$ receptor blockade without NO release.

• Journal of Biomedical Engineering Research
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• v.31 no.3
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• pp.199-209
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• 2010

The locking compression plates-distal femur(LCP-DF) are being widely used for surgical management of the extra-articular complex fractures of the distal femur. They feature locking mechanism between the screws and the screw holes of the plate to provide stronger fixation force with less number of screws than conventional compression bone plate. However, their biomechanical efficacies are not fully understood, especially regarding the number of the screws inserted and their optimal configurations. In this study, we investigated effects of various screw configurations in the shaft and the condylar regions of the femur in relation to structural stability of LCP-DF system. For this purpose, a baseline 3-D finite element (FE) model of the femur was constructed from CT-scan images of a normal healthy male and was validated. The extra-articular complex fracture of the distal femur was made with a 4-cm defect. Surgical reduction with LCP-DF and bone screws were added laterally. To simulate various cases of post-op screw configurations, screws were inserted in the shaft (3~5 screws) and the condylar (4~6 screws) regions. Particular attention was paid at the shaft region where screws were inserted either in clustered or evenly-spaced fashion. Tied-contact conditions were assigned at the bone screws-plate whereas general contact condition was assumed at the interfaces between LCP-DF and bone screws. Axial compressive load of 1,610N(2.3 BW) was applied on the femoral head to reflect joint reaction force. An average of 5% increase in stiffness was found with increase in screw numbers (from 4 to 6) in the condylar region, as compared to negligible increase (less than 1%) at the shaft regardless of the number of screws inserted or its distribution, whether clustered or evenly-spaced. At the condylar region, screw insertion at the holes near the fracture interface and posterior locations contributed greater increase in stiffness (9~13%) than any other locations. Our results suggested that the screw insertion at the condylar region can be more effective than at the shaft during surgical treatment of fracture of the distal femur with LCP-DF. In addition, screw insertion at the holes close to the fracture interface should be accompanied to ensure better fracture healing.

• Journal of Korean Neurosurgical Society
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• v.60 no.6
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• pp.611-619
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• 2017

Objective : In addition to bone bridging inside a cage or graft (intragraft bone bridging, InGBB), extragraft bone bridging (ExGBB) is commonly observed after anterior cervical discectomy and fusion (ACDF) with a stand-alone cage. However, solid bony fusion without the formation of ExGBB might be a desirable condition. We hypothesized that an insufficient contact area for InGBB might be a causative factor for ExGBB. The objective was to determine the minimal area of InGBB by finite element analysis. Methods : A validated 3-dimensional, nonlinear ligamentous cervical segment (C3-7) finite element model was used. This study simulated a single-level ACDF at C5-6 with a cylindroid interbody graft. The variables were the properties of the incorporated interbody graft (cancellous bone [Young's modulus of 100 or 300 MPa] to cortical bone [10000 MPa]) and the contact area between the vertebra and interbody graft (Graft-area, from 10 to $200mm^2$). Interspinous motion between the flexion and extension models of less than 2 mm was considered solid fusion. Results : The minimal Graft-areas for solid fusion were $190mm^2$, $140mm^2$, and $100mm^2$ with graft properties of 100, 300, and 10000 MPa, respectively. The minimal Graft-areas were generally unobtainable with only the formation of InGBB after the use of a commercial stand-alone cage. Conclusion : ExGBB may be formed to compensate for insufficient InGBB. Although various factors may be involved, solid fusion with less formation of ExGBB may be achieved with refinements in biomaterials, such as the use of osteoinductive cage materials; changes in cage design, such as increasing the area of polyetheretherketone or the inside cage area for bone grafts; or surgical techniques, such as the use of plate/screw systems.

• Journal of the korean academy of Pediatric Dentistry
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• v.31 no.1
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• pp.108-113
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• 2004

This study was to evaluate and compare differences of the cervical vertebral skeletal maturity of normal occlusion and skeletal Class III malocclusion. Normal occlusion (172 girls) and skeletal Class III malocclusion(191 girls) were classified according to diagnosis stone model and lateral cephalogram of Korean girls aging from 8 to 12 years. The concavity of inferior border, vertico-horizontal ratio of cervical vertebrae were observed and measured according to age. Differences of the cervical vertebral skeletal maturity were evaluated. The results were as follows : 1. The concavity of inferior border of the 2nd to 6th vertebrae of normal occlusion and skeletal Class III had uniformly increased with age. 2. The vertico-horizontal ratio of the 3rd to 6th vertebrae of girls with normal occlusion and skeletal Class III had uniformly increased with age. 3. There was no significant difference in cervical vertebral skeletal maturity between normal occlusion and skeletal Class III malocclusion in the concavity of inferior border of the 2nd to 6th vertebrae and in the vertico-horizontal ratio of the 3rd to 6th vertebrae. The results in the study indicate that there is no significant difference of cervical vertebral skeletal maturity between girls with normal occlusion and skeletal Class III malocclusion.

• Journal of Gastric Cancer
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• v.1 no.1
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• pp.4-9
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• 2001

Purpose: The trefoil factor family 1 (TFF1) has a protective effect against gastric mucosal damage induced by nonsteroidal anti-inflammatory drugs or ethanol. In addition, a TFF1 knockout mouse model has exhibited circumferential adenomas with high-grade dysplasia, of which $30\%$ progressed into frankly invasive carcinomas. We tried to determine whether the expression pattern of the TFF1 could be involved in the development of sporadic gastric carcinomas. Materials and Methods: We examined TFF1 expression in a series of 43 sporadic gastric carcinomas and 18 gastric adenomas by immunohistochemistry. Results: Strong positive TFF1 staining was identified primarily in the normal gastric mucosa, mainly in the cytoplasm of the superficial and foveolar epithelium. We found TFF1 expression in $55.8\%$ (24 out of 43) of the gastric carcinomas and in $16.7\%$ (3 out of 18) of the gastric adenomas. Statistically, TFF1 immunoreactivity was significantly higher in diffuse-type ($82.4\%$) than in intestinal-type ($38.5\%$) carcinomas(p=0.0058, Fisher's exact test). Conclusion: Our findings provide sufficient evidence that the expression of TFF1 in gastric cancer may simply disclose gastric-type differentiation of neoplastic cells and provide further support for the existence of at least two pathways of malignant transformation of the gastric mucosa: one via intestinal metaplasia and adenomatous dysplasia, leading to glandular carcinomas with intestinal-type differentiation, and the other via hyperplastic changes or de novo changes, leading to diffuse carcinomas and to a subset of glandular carcinomas displaying gastric-type differentiation.