Junichi Shida

Localization and quantification of proliferating cells during rat fracture repair: detection of proliferating cell nuclear antigen by immunohistochemistry.

Bilateral femurs of 12‐week‐old female Sprague‐Dawley rats were fractured, and the fractured femurs were harvested 36 h, 3, 7, 10, and 14 days after the fracture. Localization of cell proliferation in the fracture calluses was investigated using immunohistochemistry with antiproliferating cell nuclear antigen (PCNA) monoclonal antibodies. Thirty‐six hours after the fracture, many PCNA‐positive cells were observed in the whole callus. The change was not limited to mesenchymal cells at the fracture site where the inflammatory reaction had occurred, but extended in the periosteum along almost the entire femoral diaphysis where intramembranous ossification was initiated. On day 3, periosteal cells or premature osteoblasts in the newly formed trabecular bone during intramembranous ossification still displayed intense staining. On day 7, many premature chondrocytes and proliferating chondrocytes were PCNA positive. Endochondral ossification appeared on days 10 and 14, and the premature osteoblasts and endothelial cells in the endochondral ossification front were stained with anti‐PCNA antibodies. Quantification of PCNA‐positive cells was carried out using an image analysis computer system, obtaining a PCNA score for each cellular event. The highest score was observed in the periosteum early after the fracture near the fracture site. Immunohistochemistry using anti‐PCNA antibodies showed that the distribution of proliferating cells and the degree of cell proliferation varied according to the time lag after the fracture, suggesting the existence of local regulatory factors such as growth factors, and that significant cell proliferation was observed at the beginning of each cellular event.

Serum 1α,25-Dihydroxyvitamin D3 Accumulates into the Fracture Callus during Rat Femoral Fracture Healing

1,25-dihydroxyvitamin D3 (1,25(OH)2D3) is thought to be an important systemic factor in the fracture repair process, but the mechanism of action of 1,25(OH)2D3 has not been clearly defined. In this study, the role of 1,25(OH)2D3 in the fracture repair process was analyzed in a rat closed femoral fracture model. The plasma concentration of 1,25(OH)2D3 rapidly decreased on day 3 and continued to decrease to 10 days after fracture. We assessed whether this decrease was based on the accelerated degradation or retardation of the synthesis rate of 1,25(OH)2D3, from 25(OH)D3. After radiolabeled 3H-1,25(OH)2D3 or 3H-25(OH)D3 was injected i.v. into fractured or control (unfractured) rats, the concentrations of 25(OH)D3 and 1,25(OH)2D3 metabolites were measured by HPLC. The plasma concentrations of these radiolabeled metabolites in fractured group were similar to those in control rats early after operation. However, radioactivity in the femurs of fractured rats was higher than that of the control group. Furthermore, the radioactivity was concentrated in the callus of the fractured group analyzed by autoradiography. 1,25(OH)2D3 receptor gene expression was detected early after fracture and, additionally, both in the soft and hard callus on days 7 and 13 after fracture. These results showed that the rapid disappearance of 1,25(OH)2D3 in the early stages after fracture was not due to either increased degradation or decreased synthesis of 1,25(OH)2D3, but rather to increased consumption. Further, these results suggest the possibility that plasma 1,25(OH)2D3 becomes localized in the callus and may regulate cellular events in the process of fracture healing.

Traumatic atlanto-occipital dislocation with atlantoaxial subluxation.

Study Design. This is a case report of a patient who survived traumatic atlanto-occipital dislocation with atlantoaxial subluxation. Objective. To describe the useful points of 3-dimensional computerized tomography (CT) and magnetic resonance imaging (MRI) for an evaluation of atlanto-occipital dislocation. Summary of Background Data. Atlanto-occipital dislocation is a severe ligamentous injury that usually results in either a fatal outcome or severe neurologic deficit. To our knowledge, no patient who has survived atlanto-occipital dislocation with atlantoaxial subluxation has yet been reported. Methods. Three-dimensional CT was performed to confirm the diagnosis of atlanto-occipital dislocation and precisely evaluate the magnitude of displacement. MRI clearly showed a disruption of the ligamentous structures, which play a role as the primary stabilizers of the cranium on the cervical spine. Results. As soon as the patients general condition improved, the posterior spinal fusion with internal fixation was performed to maintain the stability of cervical spine. A significant degree of motor function was regained within 2 years after injury. Conclusions. In this case, the diagnosis was accurately confirmed, and the cervical spine was evaluated in detail using both 3-dimensional CT and MRI as a reliable examination for atlanto-occipital dislocation.

Administration of growth hormone modulates the gene expression of basic fibroblast growth factor in rat costal cartilage, both in vivo and in vitro

We examined the effect of growth hormone on local growth factor mRNA expression in male Sprague-Dawley rats. Repetitive systemic administration of growth hormone (0.4 IU every 4 h) increased the expression of IGF-I mRNA up to 2.8-fold in costal cartilage tissue compared with controls. Basic FGF (bFGF) mRNA expression gradually increased up to 15.5-fold compared with pre-injection samples, where the mRNA expression was 5.3-times greater than vehicle-injected controls. TGF-beta mRNA showed little changes. Moreover, one microgram/ml of growth hormone enhanced the expression of bFGF mRNA in costal chondrocytes in culture. We conclude that growth hormone increased the local expression of bFGF, as well as that of IGF-I, in cartilage, and suggest that bFGF is directly regulated by growth hormone within a local area.

Basic fibroblast growth factor regulates expression of growth factors in rat epiphyseal chondrocytes.

Chondrocytes produce several local regulatory factors such as basic fibroblast growth factor (bFGF), transforming growth factor‐β (TGF‐β) and insulin‐like growth factor‐I (IGF‐I). In this study, we examined the effect of bFGF on the expressions of both mRNA and protein of the growth factors synthesized by chondrocytes. Treatment of chondrocytes with bFGF (1–100 ng/ml) stimulated the mRNA expression of bFGF and TGF‐β up to 121–604% and 130–220% at 12 h compared with the controls, respectively. On the other hand, the treatment of chondrocytes with bFGF (1–100 ng/ml) suppressed IGF‐I mRNA expression to 79–47% at 12 h compared with the controls. An enzyme‐linked immunosorbent assay (ELISA) revealed that the treatment of chondrocytes with bFGF (1–100 ng/ml) also enhanced the production of TGF‐β1 proteins in the chondrocytes up to 299–508% at 24 h compared with controls. We conclude that bFGF influenced the local expression of growth factors by chondrocytes, suggesting autoregulation of growth factor expression during chondrogenesis.

Degenerative Change in the Adjacent Segments to the Fusion Site after Posterolateral Lumbar Fusion with Pedicle Screw Instrumentation : A Minimum 4-Year Follow-up

BACKGROUND Controversy remains regarding the subsequent degeneration of adjacent segments, and little reliable information could be found in the literature regarding long-term clinical results and adjacent segment degeneration. The objective of this study is to investigate the degenerative change of adjacent segments to the fusion site and clinical outcome after posterolateral lumbar fusion with pedicle screw instrumentation and identify the risk factors in degenerative change at adjacent segments. METHODS Thirty-two patients who underwent posterolateral lumbar fusion and were able to be followed over four years were evaluated in this study. The intervertebral disc height, percent of slip, lumbosacral joint angle, lumbar lordosis and disc angle were all examined. The postoperative progression of degeneration at adjacent segments were defined as more than a 50 % narrowing in the adjacent disc height or more than a 5 % slip in adjacent segments in comparison to the preoperative neutral lateral radiographs. The clinical results were assessed using an evaluation scores for lumbar lesions proposed by the Japanese Orthopedic Association. RESULTS Fifteen (46.8%) of the 32 patients had adjacent segment degeneration including slip or narrowing. No significant correlation was found between the adjacent segment degeneration and the recovery rate at the final follow-up. In addition, no significant correlation was observed between the adjacent segment degeneration at the lastest follow-up and postoperative radiographic measurements. CONCLUSIONS The rate of radiographic degeneration at the adjacent segments was 46.8%. No significant correlation was found between degenerative change in the adjacent segments and the clinical results. We could not identify any preoperative radiographic factors which might have influenced the segments adjacent to the fusion.

Subchondral insufficiency fracture of the femoral head in a patient with alkaptonuria.

We report a patient with alkaptonuria accompanied by bilateral rapidly destructive arthrosis of the hip. The destruction of the left hip joint with its severe functional impairment necessitated total hip arthroplasty (THA). The outcome was satisfactory. Both magnetic resonance imaging (MRI) and pathologic findings were compatible with a subchondral insufficiency fracture. A year and half later, during a follow-up visit, the patient complained of right coxalgia. Radiography showed that the right femoral head had already disappeared, requiring THA of the right hip. Although there have been a few reports of rapid destructive hip osteoarthritis associated with ochronotic arthropathy, the pathogenesis of the destructive change is not clear. Subchondral insufficiency fracture was diagnosed on MR imaging and pathologically confirmed in our patient with alkaptonuria, suggesting that subchondral insufficiency fracture is one of the causes of ochronotic hip destruction.

A Case of Traumatic Both Ends of the Clavicle Dislocations

外傷により右肩鎖関節後方脱臼と右胸鎖関節前方脱臼を認めた症例を報告する．症例は46歳，女性 右肩を後方から地面と車のバンパーにはさまれて受傷．近医入院し2週間後に当院受診．単純X線上右肩鎖関節後方脱臼，右胸鎖関節前方脱臼，肋骨骨折が認められた．受傷後3週の時点で我々は鎖骨両端脱臼に対し観血的整復術を行った．術後，整復位は保たれ，比較的患者の満足が得られる結果となり，鎖骨両端脱臼に対し観血的治療は有効な治療法であると思われた．