Munenori Watanuki

Does estrogen alter the mechanical properties of the anterior cruciate ligament?: An experimental study in rabbits

Background It is well known that anterior cruciate ligament (ACL) injuries are commoner in female athletes. Accordingly, we hypothesized that serum estrogen may play some role in this sex difference. We evaluated the relationship between serum estrogen levels and the mechanical properties of the ACL in rabbits. Animals and methods In 40 ovariectomized rabbits, the serum estrogen levels (SEL) were controlled by intramuscular injection of 17β-estradiol. The mean SEL in each rabbit was defined as the average of 5 determinations done at 1, 2, 3, 4 and 5 weeks after ovariectomy. The animals were divided into 4 groups according to the dose of estradiol administered (low, medium, high and control: L, M, H and C, respectively) and into 2 groups according to the mean SEL (high-SEL group and low-SEL group). The medial portions of ACL attached to both femur and tibia harvested at 5 weeks after ovariectomy were examined mechanically. Results The mean serum estrogen levels in groups C, L, M and H were 37, 50, 60 and 231 pg/mL. Statistically significant differences in the mean serum estrogen levels were seen among the 4 groups, except between groups L and M. Statistically significant differences were found between groups M and H in both the ultimate tensile stress and linear stiffness. In the comparison between 2 groups using the mean SEL value, both ultimate tensile stress and linear stiffness were lower in the high-SEL group. In all animals, a positive correlation was found between ultimate tensile stress and linear stiffness. Interpretation Our findings suggest that high SEL might be one of the factors in the multifactorial pathogenesis of ACL rupture.

Gene Expression Analysis of Ectopic Bone Formation Induced by Electroporatic Gene Transfer of BMP4

Implantation of bone morphogenetic protein (BMP) using a carrier or by BMP gene transfer into rodent muscle can induce bone formation. Implanted BMP becomes bioactive immediately after implantation. In BMP gene transfer, there is a time-lag between the secretion of gene products and bone formation. We analyzed the gene expression of chondrogenic and osteogenic specific markers in the process of ectopic bone formation by using semi-quantitative RT-PCR. A plasmid vector containing mouse BMP4 gene (pCAGGS-BMP4) was transferred into the gastrocnemius muscles of mice using electroporation. Histological examination revealed the process of endochondral bone formation in the pCAGGS-BMP4 transferred muscles. As chondrogenic markers, aggrecan gene maximal expression was detected on day 7 and decreased by day 14, and for collagen X the gene maximal expression was on day 10. As osteogenic markers, osteocalcin (OCN), bone sialoprotein (BSP) and osteopontin (OPN) gene expressions were clearly detected from day 10 and then increased by day 14. In conclusion, the present study proved that ectopic bone formation by BMP4 gene transfer into the muscle induced endochondral ossification that corresponded well with that to that by implantation of demineralized bone matrix.

Calcific myonecrosis and the role of imaging in the diagnosis: A case report

Calcific myonecrosis is a rare posttraumatic complication characterized by the replacement of muscles of one or more compartments with central liquefaction and peripheral calcification. We report magnetic resonance imaging (MRI) and CT imaging features of calcific myonecrosis arising 43 years after trauma. A 62-year-old man presented with a slowly enlarging mass in the left lower leg. Plain radiographs revealed a soft tissue mass with extensive amorphous calcification. The middle third of the tibia and fibula were eroded. MRI demonstrated peripheral ring enhancement on postcontrast fat-suppressed T1-weighted images. Volume-rendered images extracting only the images of bone and vessels also showed many branches from the tibialis posterior and peroneal arteries around the bone defect. During the operation, bleeding continued heavily from the vessels penetrating the cortical bone of the tibia, from the posterior compartment, and from the branches of tibialis posterior artery. The total blood loss was approximately 2,400 milliliters. There may be a causal relationship between massive bleeding and the hypervascularity of this tumor as evidenced by MRI and volume-rendering CT studies.

Effect of low-intensity pulsed ultrasound on scaffold-free ectopic bone formation in skeletal muscle

Abstract Background. Low-intensity pulsed ultrasound (LIPUS) is reported to have the effects of rapid appearance and early maturation of ossification in animal models. Method. We examined the influence of LIPUS on bone formation in C57BL/6J mouse muscle induced by gene transfer of BMP-4 expression plasmid. Electroporation was employed to transfer plasmid DNA. First, an in vitro study was carried out to confirm that LIPUS has no effect on the forced expression of BMP-4 gene transferred by electroporation into C2C12 cells. Next, the BMP-4 plasmids were injected into mouse calf muscles, and transcutaneous electroporation was applied. LIPUS (30 mW/cm2) exposure was performed daily for 20 minutes on one side of hind limbs (LIPUS side). The contralateral limbs were not exposed to LIPUS (control side). Muscle samples were collected at 7, 10, 14, and 21 days after electroporation. Soft X-ray films of muscles were taken, and areas of bone formation were measured. After pepsin solubilization of the muscles, calcium and total collagen content were measured. Results. Radiographical measurements showed significantly more bone formation in the LIPUS side at Day 10. The area of bone was the maximum in both sides at Day 14. The LIPUS side exhibited significant increase in the calcium content at Day 10. The total collagen content with LIPUS exposure was increased significantly over control at Day 10 and 21. Conclusions. According to these results, accelerated maturation of ectopic bone formation by LIPUS was confirmed at Day 10. Moreover, our results showed that LIPUS increases the total collagen content during osteogenesis.

Multiple Bone Metastasis of Sclerosing Epithelioid Fibrosarcoma 12 Years after Initial Surgery—Increasing Ki-67 Labeling Index

Sclerosing epithelioid fibrosarcoma (SEF) is a rare sarcoma of low-grade malignancy. There has been no report to describe the comparison of histological features of SEF between primary and metastatic lesions in spite of high local recurrence rate. We report the histological changes and increasing Ki-67 labeling index of the primary and metastatic lesions of SEF. The patient was a 31-year-old man. At 18, a tumor in the abdominal wall was excised. At 23, the tumor recurred which was removed again. At 30, he was referred to our hospital because of swelling and pain in the chest. Histological examination of the chest wall tumor showed epithelioid cells arranged like alveolar pattern with dense collagen stroma. These findings were consistent with those of SEF. Abdominal and the rib tumors showed the same immunohistochemistrical expression. It is noteworthy that the tumor cells of the rib lesion showed increased cellularity, and its Ki-67 activity was higher as compared with the abdominal tumor, suggestive of progression of malignancy of SEF.

Secondary osteosarcoma arising after treatment for childhood hematologic malignancies

Abstract Secondary osteosarcoma arising after the treatment of hematologic malignancies other than Hodgkins lymphoma is rare. We report two cases of secondary osteosarcoma arising after treatment for childhood hematologic malignancies (non-Hodgkins lymphoma and lymphoblastic leukemia). A 10-year-old boy, at the age of 3, was diagnosed with non-Hodgkins lymphoma. He received chemotherapy, radiation, and bone-marrow transplantation and then was in complete remission. At 6 years, he complained of increasing pain of the right thigh and was diagnosed with osteoblastic osteosarcoma. A 26-year-old man, at the age of 6, was diagnosed as having acute lymphoblastic leukemia (ALL). He received chemotherapy, radiation, and peripheral blood stem cell transplantation (PBSCT). At 11 years after PBSCT, he visited with the complaint of left lumbar swelling. He was diagnosed with chondroblastic osteosarcoma. In both cases alkaline phosphatase (ALP) had already increased prior to the onset of the symptom. We should rule out secondary osteosarcoma at the abnormal elevation of ALP during clinical follow-up of patients after treatment of childhood hematologic malignancies.

Clinical features and radiological findings of 67 patients with SAPHO syndrome

Abstract Objectives: The purpose of this study was to facilitate the understanding of the SAPHO (Synovitis, Acne, Pustulosis, Hyperostosis, and Osteitis) syndrome by analyzing the clinical and radiological features of 67 Japanese patients with SAPHO syndrome. Methods: Sixty-seven Japanese patients (female/male: 44/23, mean age at onset: 48.5 years) were diagnosed with SAPHO syndrome from 2002 to 2013 at our hospital. Medical records and radiological imaging of these patients were retrospectively reviewed. Results: Among the 67 patients, 41 had dermatological manifestations, such as palmoplantar pustulosis, acne, and psoriasis. Initial symptom was local pain in all patients, and the most common initial site of the symptom was the anterior chest. Bacterial and fungal cultures from 20 bone biopsies were all negative. Histopathological diagnosis of the specimens was non-specific inflammation in all cases. Bone lesions were observed in 65 patients (97.0%). On the other hand, articular lesions including enthesitis were found in 31 patients (46.2%). Conclusion: SAPHO syndrome had different clinical and radiological aspects. The clinical features were not remarkable, except the dermatological manifestations and the involvement of the anterior chest. Bone lesions including hyperostosis and osteitis were found radiographically in the majority of patients with SAPHO syndrome. These are the characteristics of the SAPHO syndrome, with the exclusion of other bone diseases.

Intraneural ganglion: review of the literature

Ganglions which occur in the nerves are named intraneural ganglion or nerve sheath ganglion. It should be considered in the differential diagnosis of any tumors causing neural disturbance. We review an intraneural ganglion, particularly arising in the common peroneal nerve with emphasis placed on usefulness of MRI for detecting this very unusual condition. MRI can clearly visualize a multilobular mass in the course of the nerve near the joint. The mass has low-signal intensities on T1-weighted images and homogenously high-signal intensities on T2-weighted images. The alteration of signal intensities of the muscles in the innervated compartments due to denervation is another finding for this unusual condition. During the surgery, dissection between ganglia and the nerve is difficult due to adhesions. Early diagnosis and treatment are recommended to prevent nerve damage.

Myositis ossificans of the rotator cuff muscle

Myositis ossificans of the rotator cuff muscle is a very rare condition and its pathology is poorly understood. Although several radiological findings characterizing this condition have been reported in the literature, making a definite diagnosis is sometimes difficult without histological examination. We report a case of a 52-year-old female with myositis ossificans arising in the supraspinatus muscle with histological findings from the biopsy specimen. The patient was informed that her data would be submitted for publication, and gave consent.

Adamantinoma arising in the distal end of the fibula

Adamantinoma is a rare, low-grade, malignant bone tumor. It frequently occurs in the tibia but rarely arise in the distal end of the fibula. This study reported a case of adamantinoma arising in the distal end of the fibula, resulting in good prognosis. A 38-year old female felt left ankle pain, and was suspected as having a bone tumor at the distal end of the fibula by X-ray. She was diagnosed as the classical adamantinoma of the fibula by open biopsy. En bloc wide resection of the tumor, primary arthrodesis of the ankle was performed. During the follow-up period of 7 years after the surgery, she has lived without any metastasis and local recurrence. A wide resection and arthrodesis of the ankle joint can provide a good outcome for adamantinoma arising in the end of the fibula.