Spinal Fusion Based on Ex Vivo Gene Therapy Using Recombinant Human BMP Adenoviruses / 영남의대학술지

PURPOSE: Bone morphogenetic proteins (BMPs) play an important role in the formation of cartilage and bone, as well as regulating the growth of chondroblasts and osteoblasts. In this study, we investigated whether recombinant human BMP adenoviruses are available for ex vivo gene therapy, using human fibroblasts and human bone marrow stromal cells in an animal spinal fusion model. MATERIALS AND METHODS: Human fibroblasts and human bone marrow stromal cells were transduced with recombinant BMP-2 adenovirus (AdBMP-2) or recombinant BMP-7 adenovirus (AdBMP-7), referred to as AdBMP-7/BMSC, AdBMP-2/BMSC, AdBMP-7/HuFb, and AdBMP-2/HuFb. We showed that each cell secreted active BMPs by alkaline phosphatase staining. Since AdBMP-2 or AdBMP-7 tranducing cells were injected into the paravertebral muscle of athymic nude mice, at 4 weeks and 7 weeks, we confirmed that new bone formation occurred by induction of spinal fusion on radiographs and histochemical staining. RESULTS: In the region where the AdBMP-7/BMSC was injected, new bone formation was observed in all cases and spinal fusion was induced in two of these. AdBMP-2/BMSC induced bone formation and spinal fusion occurred among one of five. However, in the region where AdBMP/HuFb was injected, neither bone formation nor spinal fusion was observed. CONCLUSION: The osteoinductivity of AdBMP-7 was superior to that of AdBMP-2. In addition, the human bone marrow stromal cells were more efficient than the human fibroblasts for bone formation and spinal fusion. Therefore, the results of this study suggest that AdBMP-7/ BMSC would be the most useful approach to ex vivo gene therapy for an animal spinal fusion model.

Morphological Study for Osteoinduction by Human Fibroblasts Transduced with rhBMP-7 Adenovirus / 대한해부학회지

To evaluate availability of the BMP-7 adenovirus (AdBMP-7) as a gene therapy for osteoinduction, we investigated in morphological aspect at 1, 2, 4, 6 weeks after cells injection. Primary cultured human dermal fibroblasts, transduced with AdBMP-7, were injected into gastrocnemius muscle of the nude mice. One week after fibroblasts transplantation new tissue was observed in the muscle. Majority of new tissue was evaluated as cartilage and calcification in the matrix was confirmed by Von Kossa stain as well as electron microscopy. Two weeks after transplantation, spongy bone was built up and adipocytes were observed in intertrabecular spaces. Osteoblasts and osteoclasts were observed in the bony tissue surface. In the result of Von Kossa-Van Gieson stain, osteolysis was dominant in bony trabeculae. Bone marrow was established in 4th weeks with intertrabecular space filled up by hematopoietic cells. At the 6th weeks, the number of trabeculae decreased and thickness of the cortical bone was increased. A great part of bone matrix has laminar structure which run paralleled to surface and which included osteocytes and canaliculi. These data demonstrate that cell mediated AdBMP-7 for gene therapy initiate development of cartilage and calcification of matrix within 1 week and complete bone and bone marrow formation within 4 weeks, so then, could be made practical application for promotion of osteoinduction.

The Measurement of Size of the Pedicle Using 3 Dimensional Reconstruction Image in Idiopathic Scoliosis / 영남의대학술지

BACKGROUND: This study was conducted to analyze the height and width of the pedicle of the upper and lower levels on the concave and the convex sides. In addition, we checked for the appropriate pedicle screw size which could be screwed in without complications. MATERIALS AND METHODS: Taking a simple AP radiography in a standing position, 99 vertebrae on the major curve with the possibility of 3-D reconstruction were analyzed after checking the CT in a supine position of 22 idiopathic scoliosis. We measured Cobb's angle from a simple radiograph, and measured the size of the isthmus by the Inner Space 3-D Editor after 3-D reconstruction with the Inner Space 3-D program in the DICOM file transformed from CT image. We then analyzed the size of pedicles of the upper and lower levels on the concave and the convex sides by measuring the height and width of the pedicle. RESULTS: All pedicles on the concave side were smaller than those on the convex side. Their size increased as the measurement moved from the upper to lower vertebra, except for the upper thoracic vertebra. When the width of the pedicle through 3-D reconstruction was compared with the narrowest width of the pedicle measured by using CT, the width of the pedicles through 3-D reconstruction was statistically smaller (P< 0.01). Most of the pedicles were tear-drop or kidney shaped rather than cylindrical. CONCLUSION: These results suggest that the use of the coronal plane through 3-D reconstruction would be necessary for an accurate measurement of the size of the pedicle. It is important to pay careful attention to the screw size and the screwing method considering the pedicle shape through 3-D reconstruction.

Bone Formation by rhBMP-7 Transduced HEK 293 Cells in Nude Mouse / 영남의대학술지

To induce bone formation at ectopic site by tissue engineering and gene therapy, we transplanted collagen sponges containing rhBMP-7 transduced HEK 293 cells in the hypodermis of nude mice. Bone formation was investigated by histological and electron microscopic method at 3, 6, and 9 weeks after transplantation. At 9 weeks after transplantation, eosinophilic bony tissue was observed in the implanted collagen sponge and was confirmed as bone tissue by Von Kossa stain. In the transmission electron microscopic observation, the cells in newly formed bone tissue had eccentrically located nucleus and well developed rough endoplasmic reticulum (rER). Therefore, the cells were evaluated as osteoblasts. Those results suggest that it is possible to form a bone tissue in the ectopic site by transplantation of rhBMP-7 transduced HEK 293 cells. This will be contributed to push more advanced gene therapy for bone formation. However, the HEK 293 cell is unable to apply to the clinical gene therapy. Therefore it is worth to find more compatible cells for clinical application. In addition, collagen sponge is considered as an excellent scaffold and/or carrier for gene therapy and a good biomaterial for tissue engineering.

Bone Formation by rhBMP-7 Transduced HEK 293 Cells in Nude Mouse / 영남의대학술지

To induce bone formation at ectopic site by tissue engineering and gene therapy, we transplanted collagen sponges containing rhBMP-7 transduced HEK 293 cells in the hypodermis of nude mice. Bone formation was investigated by histological and electron microscopic method at 3, 6, and 9 weeks after transplantation. At 9 weeks after transplantation, eosinophilic bony tissue was observed in the implanted collagen sponge and was confirmed as bone tissue by Von Kossa stain. In the transmission electron microscopic observation, the cells in newly formed bone tissue had eccentrically located nucleus and well developed rough endoplasmic reticulum (rER). Therefore, the cells were evaluated as osteoblasts. Those results suggest that it is possible to form a bone tissue in the ectopic site by transplantation of rhBMP-7 transduced HEK 293 cells. This will be contributed to push more advanced gene therapy for bone formation. However, the HEK 293 cell is unable to apply to the clinical gene therapy. Therefore it is worth to find more compatible cells for clinical application. In addition, collagen sponge is considered as an excellent scaffold and/or carrier for gene therapy and a good biomaterial for tissue engineering.

An Assessment of the Mechanical Properties of Long Bone Fractures Using an Impulse Response Method / 대한정형외과학회잡지

PURPOSE: To establish the basis for a non-invasive and non-destructive assessment of the mechanical properties during natural fracture healing by analyzing the vibrational property of the fracture healing and comparing the vibrational property, the bone healing status (as determined by X-ray) and the mechanical strength parameters. MATERIALS AND METHODS: The tibial shafts of rabbits were broken under general anesthesia. The rabbits were sacrificed at 2, 4, 6 weeks after the fracture, then X-rays of the fractured tibias were sequentially taken to detect the fracture healing. The vibration mode and the biomechanical strength were measured. RESULTS: According to the results of a multiple regression analysis, the standardized coefficients of callus, apposition, lateral angulation, DAMP1, FREQ1 in the fractured tibias, were -0.80, -0.23, -0.21, -0.25, -0.25. In normal contralateral tibias, the standardized coefficients of the area, FREQ1, DAMP1, FREQ2, DAMP3 were -0.73, 0.28, 0.41, 0.39, -0.25. CONCLUSION: A monitoring of the fracture healing process that utilizes the frequency response function is thought to be useful in detecting the early phase of healing within 4 weeks. Additional studies on the vibrational characteristics of the healing bones after a clinical union or after simillar pathologies should be pursued so that future diagnostic applications ca be made.

An explorative study of the contributing factors in changes in one density according to aging / 대한정형외과학회잡지

No abstract available.

The Treatment of Tibial Shaft Fractures by Interlocking Nailing / 영남의대학술지

The treatment of tibial shaft fracture has become one of the most controversial subjects in orthopedic surgery. Comminuted, segmental and rotationally unstable fractures or bone defect at fraction site have problems of the fixation. The interlocking nail solve these problems. We have experienced 8 cases of the tibial shaft fractures treated with interlocking nail from 1986 to 1988. Authors analyzed these cases and out own clinical study. The results were as follows. 1. The average bone union rate was about 15 weeks. 2. The interval between operation and crutch walking was 4.3 weeks. 3. The merits of this operation were the short hospitalization and early adaptation of social activity. 4. The advantage is be able to do early ambulation without following muscular atrophy or joint stiffness. 5. The results were assessed on clinical examination and radiographic appearance by Hamza et al. An excellent results were 7 cases and good result was 1 case.

A Clinical Analysis Femur Neck Fracture in Elderly Patients / 영남의대학술지

Femur neck fracture is well known as one of the major death cause after trauma in elderly patients, and unsolved fracture due to its frequent association with complications such as avascular necrosis and nonunion. Through meticulous evaluation of the patient, hip and surgeon's experiences, reduction of mortality and morbidity as well as rapid recovery of the patient to the preinjury social and ambulatory status without local complications and revision after treatment is urgently needed. Many factors about this fracture in itself were noted, but we have analyzed 18 femur neck fracture of the patients older than 50 years preliminarily according to age, fracture pattern, osteoporosis, etiology and method of treatment with its delay in association with major complications especially avascular necrosis and nonunion. The results are as follows; 1. Of these 18 fractures, 11 were in females, 8 were caused by minor trauma such as slipdown accident and 4 were associated with definite osteoporosis according to the Sing's classification. 2. Fracture pattern of these 18 are undisplaced in 4, displaced subcapital in 11, displaced transcervical in 3. 11 fractures in the patients older than 60 year are composed of 3 undisplaced or impacted fractures and 8 displaced subcapital fractures. 3. These 18 fractures were treated by closed reduction and internal fixation with multiple pins in 13, and hemiarthroplasty in 4, but one was not treated to die after discharge from hospital. 4. Undisplaced or impacted fractures and 3 displaced transcervical fractures were not associated with any complications such as avascular necrosis or nonunion. But 4 of 6 displaced subcapital fractures were complicated by avascular necrosis, 3 of which were reduced in the varus position within 1 week, and the other was reduced in the good position on 1 week after trauma. There was no complication in 2 displaced subcapital fractures reduced in valgus position within 3 days after trauma. According to the above results, the prognosis of the femur neck fracture is dependent upon the fracture pattern and delay in its treatment. So it is inevitable to reduce the fracture in anatomical or valgus position as early as possible. But the arthroplasty may be needed in displaced subcapital fractures delayed for several days, with its reluction in extreme varus position or impossible and with preexisting disease in the same hip joint (total hip replacement).

Anatomical Study Designed to Clarify the Mechanism of the Pivot Shift / 대한정형외과학회잡지

There has been much dispute about the pathomechanics and the significance of the test even among the most competent surgeons in this field. Some have claimed that the posterolateral capsule must be torn to initiate the pivot shift. Some have even gone as far as to deny the importance of the anterior cruciate ligament as a main stabilizing structure of the knee. We evaluated the concept of MacIntosh in anatomical studies which were carried out at the both Pathology and Orthopedic department of Kyungpook National University, School of Medicine, Taegu Korea. Experiments have been carried out to study the etiology of anterolateral instability and the production of a pivot shift sign. In the cadaver knees and A/K amputation knees, which did not have any sign of instability or osteoarthritis, the anterior cruciate was severed by a short medial incision. We could immediately detect a pivot shift. No pivot shift resulted however when the posterolateral capsule was completely divided first and the anterior cruciate left intact, or when the medial collateral ligament and medial capsule were cut. If both the anterior cruciate and posterolateral capsule were divided the pivot shift became more prominent than after cutting the anterior cruciate alone. When the medial collateral ligament including the capsular structures was completely severed, however, the pivot shift disappeared. In summary the experiments show the following: 1. An isolated rupture of the anterior cruciate ligament or its combination with a partial tear of the medial collateral ligament may be detected with the pivot shift sign. 2. If the rupture of the medial collateral ligament is complete the pivot shift test can be negative in spite of a tear of the anterior cruciate ligament.