Michihisa Zenmyo

MORPHOLOGICAL AND BIOCHEMICAL EVIDENCE FOR APOPTOSIS IN THE TERMINAL HYPERTROPHIC CHONDROCYTES OF THE GROWTH PLATE

The purpose of this study was to investigate the mechanism of cell death in chondrocytes of the growth plate. In the degenerative chondrocyte zone of the growth plate, apoptotic chondrocytes were defeated by the in situ nick end labelling method, by DNA analysis in agarose gel, and by electron microscopy. The results of the in situ nick end labelling method and the occurrence of a ladder pattern of DNA in agarose gel analysis indicated the activation of endogenous endonucleases, resulting in DNA fragmentation. Electron micrographs showed the early morphological changes associated with apoptosis. This report presents both morphological and biochemical evidence for apoptosis in the terminal hypertrophic chondrocytes of the growth plate. These data suggest that apoptosis of degenerative chondrocytes may play an important role in the control of normal and pathological endochondral ossification.

Inhibition of bone and muscle metastases of lung cancer cells by a decrease in the number of monocytes/macrophages

Attention has recently focused on the critical role of inflammatory responses in the tumor stroma that provide favorable conditions for cancer‐cell growth and invasion/metastasis. In particular, macrophages recruited into the tumor stroma and activated, known as tumor‐associated macrophages, are suggested to promote tumorigenesis. In this study, we examined the effect of a decrease in the number of monocytes/macrophages in peripheral blood and the tumor stroma on the development of bone and muscle metastases by lung cancer cells. Treatment with clodronate encapsulated by liposomes (Cl2MDP‐LIP) has been developed for the depletion of monocytes/macrophages in an animal model. Subcutaneous administration of Cl2MDP‐LIP markedly reduced the number of monocytes in peripheral blood, resulting in efficient suppression of both bone metastasis and muscle metastasis when lung cancer HARA‐B cells were injected into the left cardiac ventricle of mice. Treatment with Cl2MDP‐LIP significantly reduced the number of macrophages in tumors and the number of osteoclasts in bone marrow, as well as peripheral monocytes in mice harboring lung cancer cells. In contrast, treatment with an osteoclast‐targeting antibiotic, reveromycin A, inhibited bone metastasis by lung cancer cells, but not muscle metastasis. The survival of human macrophages in culture was found to be specifically blocked by Cl2MDP‐LIP, but not by reveromycin A. Cl2MDP‐LIP thus exerted antimetastatic effects in both bone and muscle whereas reveromycin A did so only in bone. Liposome‐encapsulated bisphosphonate may modulate metastasis through decreasing the number of monocytes/macrophages in both peripheral blood and the tumor stroma, suggesting that tumor‐associated macrophages might be suitable targets for antimetastatic therapy. (Cancer Sci 2008; 99: 1595–1602)

Bone Malformations in Interleukin-18 Transgenic Mice†

The in vivo effects of IL‐18 on bone metabolism were investigated by histopathology in IL‐18 transgenic mice. Deformed cortical bone and decreased turnover rate of lumbar trabecular bone are consistent with increased expression of IFN‐γ and IL‐18 in the bone marrow.

Intraneural monophasic synovial sarcoma : A case report

Study Design. A case report. Objectives. To illustrate a rare case of synovial sarcoma arising within a peripheral nerve. Summary of Background Data. A synovial sarcoma arising within a peripheral nerve is very unusual. Only five cases of primary synovial sarcoma within a peripheral nerve have been reported. This is the first case with involvement of the nerve root. The authors diagnosed the tumor arising within the S1 nerve root as synovial sarcoma using cytogenetic analysis that detected the chimeric SYT/SSX gene. Methods. In addition to the immunohistochemical study, a reverse transcription-polymerase chain reaction (RT-PCR) assay was conducted for the SYT–SS10 fusion gene using archival formalin-fixed paraffin-embedded tumor specimens. Results. Computed tomography scan, magnetic resonance imaging performed before surgery, and the intraoperative findings showed that the tumor was embedded within the S1 nerve root. Although the histologic findings were suggestive of a malignant peripheral nerve sheath tumor, the results of the cytologic study confirmed its diagnosis of synovial sarcoma. Conclusion. Primary intraneural synovial sarcoma, although rare, must be distinguished from malignant peripheral nerve sheath tumor. The molecular assay of the detection of the SYT/SSX fusion gene is useful to make a definite diagnosis of monophasic synovial sarcoma.

OSTEOSARCOMA CELL APOPTOSIS INDUCED BY SELENIUM

An essential nutrient selenium has been reported to be a potential cancer preventive and inhibitory agent, although no exact mechanism has yet been proposed. Since little is known about the anti‐proliferative effect of selenium on osteosarcoma, this issue was addressed in the present study in vitro using three osteosarcoma cell lines, and in vivo using an osteosarcoma transplantable to nude mice. Selenium inhibited the tumor growth in vitro and morphological changes indicative of apoptosis were demonstrated. Osteosarcomas in nude mice were inhibited in growth by selenium with no cytotoxic change in normal tissues. The findings suggested that selenium may offer a novel therapeutic modality for osteosarcoma.

Histamine-stimulated production of matrix metalloproteinase 1 by human rheumatoid synovial fibroblasts is mediated by histamine H1-receptors

The purpose of this study was to investigate the role of histamine in human rheumatoid synovial fibroblasts in the production of factors responsible for tissue remodelling and cartilage breakdown in rheumatoid arthritis. We examined the effects of histamine of tritiated thymidine incorporation, production of matrix metalloproteinase-1 (MMP-1), histamine H1-receptor expression, phosphoinositide metabolism and intracellular calcium ion concentration ([Ca2+]i) in human rheumatoid synovial fibroblasts. Tritiated thymidine incorporation studies demonstrated that histamine markedly stimulated the proliferation of rheumatoid synovial fibroblasts. Immunofluorescence and Northern blot analyses revealed that proMMP-1 production was also stimulated by histamine. The levels of inositol phosphates and [Ca2+]i in the cells were elevated in response to histamine, indicating that the cells expressed histamine H1-receptors; and Northern blot analysis indicated that these H1-receptors were up-regulated by histamine. In in situ hybridization, large amounts of histamine H1-receptor mRNA were also detected in rheumatoid synovial tissue. These results suggest that the interaction between H1-receptor expression in rheumatoid synovial fibroblasts and histamine secretion by mast cells and macrophages in the affected sites is an important event responsible for tissue remodelling and joint destruction in rheumatoid arthritis.

High levels of serum IL-18 promote cartilage loss through suppression of aggrecan synthesis

Osteoarthritis (OA) is closely related to the function of several inflammatory cytokines. It has been reported that older age is associated with higher serum levels of the inflammatory cytokine IL-18. In the present study, we investigated the long-term role of serum IL-18 in cartilage loss in vivo using a new strain of IL-18 transgenic mouse (Tg) in comparison with wild-type (WT) mice. The IL-18 Tg mouse strain we developed constitutively overproduces soluble mature IL-18 in the lungs but not in other tissues, including joints. These Tg mice showed high levels of serum IL-18, but not IL-1beta. No inflammatory cells, fibrillation or synovitis were observed in the knee joints of either IL-18 Tg or WT mice. However, the cartilage cellularity of the femoral and tibial condyles of IL-18 Tg mice was significantly reduced in comparison with control WT mice. Aggrecan was detected in only a few cells in the deep zone of the articular cartilage of Tg mice. The expression of aggrecan mRNA was also significantly decreased in articular chondrocytes from Tg mice when compared with WT mice. In contrast, endogenous IL-18 mRNA was significantly increased in the chondrocytes of Tg mice in comparison with WT mice. Expression of IFN-gamma was also significantly increased in the Tg mice. Moreover, IL-18 transgene-positive caspase-1-deficient mice showed articular cartilage loss that was independent of endogenous IL-1beta. In cultured chondrocytes isolated from WT mice, the expression of aggrecan mRNA was dosage-dependently suppressed by treatment with recombinant IL-18. In contrast, IL-18 stimulated the expression of mRNA for endogenous IL-18 and IFN-gamma. These results suggest that high levels of serum IL-18 promote the overexpression of endogenous IL-18 in articular chondrocytes, resulting in cartilage loss through suppression of aggrecan synthesis. Thus IL-18 may play an important role in the pathogenesis of articular cartilage loss in osteoarthritis.

Bone tumors in the pelvis presenting growth during pregnancy

Abstract Among 56 cases of a giant cell tumor of bone (GCT) and 52 cases of chondrosarcoma (CSA) in our series, four patients were discovered to have a tumor in the pelvic bone that grew in size during pregnancy. These four rare cases are described here. They include three cases of a GCT in the sacrum and one case of a CSA in the innominate bone. The dextran-coated charcoal assay and immunohistochemical techniques demonstrated the independence of these tumors from hormonal regulation despite the growth stimulated during pregnancy. It was concluded that the delay in detection of these tumors in the pelvis was just related to the opportunity afforded for unexpected growth during pregnancy. Surgical management was difficult due to the delay in tumor detection. The initial complaints such as pain, discomfort, or numbness around the pelvis were misinterpreted as symptoms of pregnancy. It should be kept in mind that during pregnancy, any pain or numbness in the pelvic region could be the direct result of a tumor in the pelvic bone.

A solitary bone cyst in the spinous process of the cervical spine: A case report

STUDY DESIGN A case report. OBJECTIVES To illustrate a rare case of histologically confirmed solitary bone cyst involving the spinous process of C7. SUMMARY OF BACKGROUND DATA A solitary bone cyst involving the spine is very unusual. Although four cases of a solitary bone cyst in the spine have been reported in the literature, the current authors have been able to find only one case of solitary bone cyst in the spinous process. All four patients reported in the literature were over 30 years of age. The patient in the current case was a 13-year-old girl with no history of trauma. METHODS Radiographs and a computed tomography scan of the cervical spine were performed before the operation, as was a histologic examination to make a diagnosis of the lesion. RESULTS The intraoperative findings from examination of the stagnant fluid within the lesion and the histologic examination indicated the diagnosis of a solitary bone cyst. CONCLUSIONS A solitary bone cyst in the spine is rare, especially in the young. An osteolytic lesion in the spinous process of the spine tends to be diagnosed as an osteoblastoma or as a giant cell tumor of the bone. A solitary bone cyst of the spine, although rare, must be considered as a differential diagnosis.

Il-6 in a pleomorphic type of malignant fibrous histiocytoma presenting high fever

We describe a rare case of pleomorphic type of malignant fibrous histiocytoma (MFH) in the buttock that presented a systemic involvement. The case was of a 58-year-old woman presenting hepatic dysfunction and inflammatory reactions including fever, positive C-reactive protein (CRP), an elevated erythrocyte sedimentation rate, and high levels of platelets and ferritin. The fever of 3 months duration subsided on the first postoperative day. The MFH resection also brought rapid normalization in CRP, platelets, and leukocytes. The local and systemic productions of cytokines induced by this tumor were evaluated. In vivo and in vitro production of interleukin (IL)-6, IL-1beta, and tumor necrosis factor alpha by tumor cells were measured using enzyme-linked immunosorbent assay. Blood samples taken preoperatively, tumor tissues, and the primary culture medium showed extraordinarily high IL-6 levels. The plasma IL-6 level was normalized postoperatively. Immunohistochemistry showed the positivity of tumor cells for IL-6. The IL-6 produced by the tumor was concluded to have been responsible for the systemic illness.