Mesenchymal stem cells (MSCs) are identified by having the ability to differentiate into various tissues and typically used to generate bone tissue by a process of resembling intramembranous ossification, namely by direct osteoblastic differentiation. However, most bones develop by endochondral ossification, namely via remodeling of hypertrophic cartilaginous templates. To date, reconstruction of bone defects by endochondral ossification using mesenchymal stem cell-derived chondrocytes (MSC-DCs) have not been reported. The purpose of this study was to evaluate the effects of the transplantation of MSC-DCs on bone healing in segmental defects in rat femurs. Segmental bone defects (5, 10, 15-millimeter) were produced in the mid-shaft of the femur of the Fisher 344 rats and stabilised with an external fixator. Bone marrow was aspirated from the rat's femur and tibia at 4 weeks before operation. MSCs were isolated and grown in culture and seeded on a Poly dl-lactic-co glycolic acid (PLGA) scaffold. Subsequently, the scaffold was cultured using chondrogenic inducing medium for 21 days. The characteristics of the PLGA scaffold are radiolucent and to be absorbed in about 4 months. The Treatment Group received MSC-DCs, seeded on a PLGA scaffold, locally at the site of the bone defect, and Control Group received scaffold only. The healing processes were monitored radiographically and studied biomechanically and histologically.Introduction
Methods
The purpose of this study was to evaluate the effects of implantation of mesenchymal stem cell derived condrogenic cells (MSC-DC) on bone healing in segmental defects in rat femur. Five-millimeter segmental bone defects were produced in the mid-shaft of the femur of Fisher 344 rats and stabilized with external fixator. The Treatment Group received MSC-DC, seeded on a PLGA scaffold, locally at the site of the bone defect, and Control Group received scaffold only. The healing processes were monitored radiographically (Softex), and studied radiographically (Micro-CT) and histologically.Purpose
Methods
what size of defect is optimal for creating an atrophic nonunion animal model has not been well defined. Our aim in this study was to establish a clinically relevant model of atrophic nonunion in rat femur by creation of a bone defect to research fracture healing and nonunion. We used 30 male Fischer 344 rats (aged 10–11 weeks), which were equally divided into six groups. The segmental bone defects to a single femur in each rat were performed by double transverse osteotomy, and different sized defects were created by group for each group (1 mm, 2 mm, 3 mm, 4 mm, 5 mm and 6 mm). The defects were measured and maintained strictly by using an original external fixator. The periosteum for each defect was stripped both proximally and distally. Thereafter, these models were evaluated by radiology and histology. Radiographs were taken at baseline and at intervals of two weeks over a period of 8 weeks. Atrophic nonunion was defined as a lack of continuity and atrophy of both defect ends radiologically and histologically at eight weeks.Introduction
Materials and methods
Reconstruction of 10mm segmental bone defects in rat by mesenchymal stem cell derived chondrogenic cells (MSC-DC) Mesenchymal stem cell derived condrogenic cells (MSC-DC) have excellent potential for healing 5 mm bone defect in rat femur. To evaluate the effectiveness of MSC-DC on bone healing in 10 mm segmental bone defects in rat femur.Background
Purpose
In February 2004, our institute began to perform routine cervical CT scans in addition to head CT examinations on patients with blunt head trauma who had received high energy injuries. We present the findings of 108 patients who underwent a routine cervical CT within the last year and the usefulness of routine cervical CT examinations is discussed. The present report is, to our knowledge, the only prospective study to examine the utility of routine cervical CT examinations. Among the patients admitted to the emergency room of our institute after receiving high energy injuries, 108 patients had blunt head trauma and underwent a routine cervical CT examination in addition to the head CT examination specified by our original protocol for cervical clearance. The mechanism of injury and the presence of cervical bone lesions were noted in each case. 76 males and 32 females ranging in age from 13 to 77 years (average, 41.0 years) were included in the study. Among these 108 cases, cervical fractures or subluxation were visible in 5 cases on plain films. Although no fractures were seen on the plain films taken in the remaining 103 cases, the additional cervical CT examinations demonstrated 14 cervical fractures in 13 (12.6%) of these cases. For patients with blunt head trauma, a cervical CT examination is not usually performed if no evidence of a cervical fracture is found on plain films and no neurological deficits are present. Nevertheless, the present findings suggest that many cervical fractures may have been missed on plain films in the past, and the routine inclusion of a cervical CT examination in addition to a head CT examination might be appropriate in the evaluation of patients with blunt head trauma who have been involved in a high energy injury.
