STATEMENT OF PROBLEM: Resonance frequency analysis has been increasingly served as a noninvasive and objective method for clinical monitoring of implant stability. Many clinical studies must be required for standardized data using RFA. PURPOSE: This study was performed to evaluate RFA value changes in two anodized implant groups. MATERIAL AND METHOD: Among a total of 24 implants, twelve screw shaped implants as a test group (H2-R8.5) were manufactured, which had a pitch-height of 0.4 mm, an outer diameter of 4.3 mm, a length of 8.5 mm, and external hexa-headed, were turned from 5 mm rods of commercially pure titanium (ASTM Grade IV, Warantec Co., Seoul, Korea), and another twelve implants as a control group were Branemark Ti-Unite MK4 (diameter 4.0 mm, length 8.5 mm). Each group was installed in tibia of rabbit. Two implants were placed in each tibia (four implants per rabbit). Test two implants were inserted in right side and control two in left side. ISQ values were measured using Osstell(TM) (Integration Diagnostics Ltd. Sweden) during fixture installation, and 12 weeks later and evaluated the RFA changes. RESULTS: Mean and SD of baseline ISQ values of test group were 75.0 +/- 3.4 and 68.7 +/- 8.1 for control group. Mean and SD of ISQ values 12 weeks after implant insertion were 73.2 +/- 4.7 for test group and 72.6 +/- 3.9 for control group. There were no statistically significant differences between groups in ISQ values after 3months (P>0.05). From the data, RFA gains after 3 months were calculated, and there was statistically significant difference between groups (P<0.05). CONCLUSION: Although there were RFA changes between groups, implant stability after experimental period shows alike tendency and good bone responses.
Seoul ; Tibia ; Titanium

BACKGROUND: It is not yet clear whether the abnormal cytokine production in relation to serum IgE levels in atopic dermatitis (AD) is associated with the amount of mRNA of cytokine gene. OBJECTIVE: Our purpose was to delineate the effect of reciprocal correlation in the level of mRNA between interleukin-4 (I") and interferon-gamma (IFN-γ) in severe AD. METHODS: We examined 15 cases including 5 AD patients with high serum IgE (>2,000 kU/liter), 5 AD patients with low serum IgE (<100 kU/liter), and 5 healthy controls. Using semi quantitative reverse transcription-polymerase chain reaction, IL-4 and IFN-γ gene expressions in peripheral mononuclear cells (PBMC) were examined. RESULTS: 1) IL-4 gene expression in spontaneous PBMC was higher in AD patient groups than in control group, significantly higher only in AD patient group with high serum IgE level (p < 0.05). 2) IFN-γ gene expression in spontaneous PBMC showed increased tendency in AD patient groups than in control group without statistical significance. 3) IL-4 and IFN-γ gene expressions in stimulated PBMC were not different among all three groups. CONCLUSION: In light of our results, high and low IgE subgroups in AD can exist and AD may not be R characterized by the shift in the reciprocal relationship between IL-4 and IFN-γ when T cells are stimulated under antigen presenting cell-independent conditions.
Dermatitis, Atopic ; Gene Expression ; Humans ; Immunoglobulin E* ; Interferon-gamma* ; Interleukin-4* ; RNA, Messenger ; T-Lymphocytes

The posterior cruciate ligament is an anatomically and biomechanically complex structure. PCL injuries are reported to occur in 1-40% of acute knee injuries, with isolated PCL tear, less common than PCL tears combined with other Iigament injuries. Controversy exists concerning the geatment of the PCL injures. Recently, arthroscopic techniques of PCL reconstruction are becoming nore refined and reproducible. Between July 1993 and May 1995, 25 operations for PCL rupture were performed in our hospital. At the follow-up examinations we noted mild to moderate posterior instablilty which was not noted at the time of operation and during the immediate postoperative period. We reviewed type (if injuries, amplitude of initial posterior tibia1 translation, surgical techniques, which seemcd to be in relation ivith the postoperative instabilities. At final follow-up, the mean Lysholm knee score was 86 points, and the posterior tibial translation 6.5mm on posterior stress radiographs. The ligament augmentation device provided no benefit. The ideal positioning and fixation of the graft and protection of the graft from abrasion seemed to be important to get a good results.
Follow-Up Studies ; Knee ; Knee Injuries ; Ligaments ; Patellar Ligament* ; Posterior Cruciate Ligament ; Postoperative Period ; Rupture ; Transplants*

Different kinds of forces can be applied to the biological tissue. The analysis of the applied force is highly important to explain the mechanism of cellular response. In this study, the applied force to the collagen gel was analyzed by the finite elements analysis. The model received two different kinds of static force (compression and tension). The force range was 50g to 400g. In results, von Mises stress was concentrated in the peripheral region in the compression model. It was concentrated in the central area in the tension model. However, the compressive force was high in the peripheral area of the compression model and the tensional force was also high in the same area of the tension model. In conclusion, the applied force could be different to the region and it should be considered in the experiment to analyze the effects of the mechanical force on the cells.
Cell Culture Techniques ; Collagen ; Finite Element Analysis

Different kinds of forces can be applied to the biological tissue. The analysis of the applied force is highly important to explain the mechanism of cellular response. In this study, the applied force to the collagen gel was analyzed by the finite elements analysis. The model received two different kinds of static force (compression and tension). The force range was 50g to 400g. In results, von Mises stress was concentrated in the peripheral region in the compression model. It was concentrated in the central area in the tension model. However, the compressive force was high in the peripheral area of the compression model and the tensional force was also high in the same area of the tension model. In conclusion, the applied force could be different to the region and it should be considered in the experiment to analyze the effects of the mechanical force on the cells.
Cell Culture Techniques ; Collagen ; Finite Element Analysis

No abstract available.

The recent trend of research and development on guided tissue regeneration focuses on the biodegradable membranes, which eliminate the need for subsequent surgical removal. They have demonstrated significant and equivalent clinical improvements to the ePTFE membranes. This study evaluate guided tissue regeneration wound healing in surgically induced intrabony periodontal defects following surgical treatment with a synthetic biodegradable membranes, made from a copolymer of glycolide and lactide, in 8 beagle dogs. After full thickeness flap reflection, exposed buccal bone of maxillary and mandibular canine and premolar was removed surgically mesiodistally and occlusoapically at 6mmx6mm in size for preparation of periodontal defects. In experimental sites a customized barrier was formed and fitted to cover the defect. Flap was replaced slightly coronal to CEJ and sutured. Plaque control program was initiated and maintained until completion of the study. In 4, 8, 16 and 24 weeks after surgery, the animals were sacrificed and then undecalcified specimens were prepared for histologic evaluation. Histologic examination indicated significant periodontal regeneration characterized by new connective tissue attachment, cementum formation and bone formation. These membranes showed good biocompatibility throughout experiodontal period. The barriers had been completely resorbed with no apparent adverse effect on periodontal wound healing at 24 weeks. These results implicated that present synthetic biodegradable membrane facilitated guided tissue regeneration in periodontal defect.
Animals ; Bicuspid ; Connective Tissue ; Dental Cementum ; Dogs* ; Guided Tissue Regeneration* ; Membranes* ; Osteogenesis ; Regeneration ; Tooth Cervix ; Wound Healing

Takayasu's arteritis is a chronic inflammatory disease of unknown etiology involving the thoracic and abdominal aorta and its major branches. In some cases other vessel such as renal arteries, coronary arteries, and even pulmonary arteries may be involved. Total aortography is very important, because the clinical features are determined by the extent and severity of the specific artery involved in the occlusive phase of the disease. We report a case of Takayasu's arteritis type IV in a 38 year man with pulmonary arterial involvement and pulmo-nary hypertension.
Aorta, Abdominal ; Aortography ; Arteries ; Arteritis* ; Coronary Vessels ; Hypertension ; Hypertension, Pulmonary* ; Pulmonary Artery ; Renal Artery ; Takayasu Arteritis*

While calcium phosphate ceramics meet some of the needs for bone replacement, they have some limitation of unresorbability and fibrous encapsulation without direct bone apposition during bone remodelling. To address these problem, we developed a new ceramic, calcium metaphosphate(CMP), and report herein the biologic response to CMP in subcutaneous tissue, muscle and bone. Porous CMP blocks were prepared by condensation of anhydrous Ca(H2PO4)2 to form non-crystalline Ca(PO3)2. Macroporous scaffolds were made using a polyurethane sponge method. CMP block possesses a macroporous structure with approximate pore size range of 0.3-1mm. CMP blocks were implanted in 8 mm sized calvarial defect, subcutaneous tissue and muscle of 6 Newzealand White rabbits and histologic observation were performed at 4 and 6 weeks later. CMP blocks in subcutaneous tissue and muscle were well adapted without any adverse tissue reaction and resorbed slowly and spontaneously. Histologic observation of calvarial defect at 4 and 6 weeks revealed that CMP matrix were mingled with and directly apposed to new bone without any intervention of fibrous connective tissue. CMP blocks didn't show any adverse tissue reaction and resorbed spontaneously also in calvarial defect. This result revealed that CMP had a high affinity for bone and was very biocompatible. From this preliminary result, it was suggested that CMP was a promising ceramic as a bone substitute and tissue engineering scaffold for bone formation.
Rabbits ; Animals

Over the past years, university administrators have known how hard it is to transform into the modern university. Rigid in-bred research system, narrow interest, unworkable graduate programs are complicatedly woven into a network of academic fraction. Cronyism and protectionism flood various laboratories and research institutes affiliated with the university. Until recently, the department structure of medical school has steadfastly guarded its territory and refused to allow non-medical undergraduate students to apply for the graduate schools of medical science. The graduate schools in medical science are considered just extra appendages because most of graduate students should be engaged in hard work position such as junior faculty or residentship training course of university hospital. In the present environment of graduate program, medical schools are consequently not able to bring in full-time young researchers, but only recently has its door been open for others. It should be time to reorganize the medical school graduate course into large multidisciplinary research group by expanding graduate programs.
Academies and Institutes ; Administrative Personnel ; Humans ; Schools, Medical*