Publications by authors named "Toshiaki Hitora"

Heat shock protein 90 (Hsp90) is constitutively expressed at 2‑10‑fold higher levels in tumor cells compared to normal cells, suggesting that it may be critically important for tumor cell growth and survival. These features make Hsp90 a potential target for anticancer drug development. Inhibition of Hsp90 activity not only results in rapid degradation of Hsp90 client proteins but also induces apoptosis of various tumor cells.

View Article and Find Full Text PDF

Introduction. Osteoma is a benign, slowly growing, asymptomatic, osteogenic neoplasm. Osteoma of a bone other than the skull and facial bones is extremely rare.

View Article and Find Full Text PDF

A breast cancer patient developed an atypical femoral fracture after 9 years of bisphosphonate therapy for the treatment of multiple bone metastases. We histopathologically analyzed the femoral cortical bone at the fracture site and the iliac cancellous bone. Four months prior to the fracture, the patient had experienced pain in the right femur and underwent plain radiography and bone scintigraphy which revealed cortical thickening and radioisotope accumulation at each site, respectively.

View Article and Find Full Text PDF

The inhibition of the mammalian target of rapamycin (mTOR) signaling pathway promotes the initiation of autophagy, and the mitogen-activated protein kinase (MAPK)/extracellular signal-regulated protein kinase (ERK) is well known to induce autophagy. Autophagy is a self-defense mechanism of cancer cells that are subjected to antitumor agents, and blocking autophagy can trigger apoptosis. In the present study, we demonstrate that an mTOR inhibitor, rapamycin, induces autophagy in the Nara-H malignant fibrous histiocytoma (MFH) cell line through the activation of ERK1/2.

View Article and Find Full Text PDF

Fibrous dysplasia (FD) is an uncommon, but well-known benign skeletal disorder. In cases affecting long bones, FD is commonly recognized to locate in the diaphyses or the metaphyses and to spare the epiphyses. In this paper, we present a rare case of polyostotic FD in a 13-year-old girl with unilateral multiple epiphyseal lesions arising in the femur, the tibia, and the fibula with the growth plates.

View Article and Find Full Text PDF

A 40-year-old man with macrodactyly of the left great toe presented with progressive enlargement of the ipsilateral ankle and increasing pain after minor trauma. Radiographs and computed tomographic scans of the foot and ankle revealed macrodactyly of the great toe and a large heterotopic ossified mass in the anteromedial aspect of the ankle. The large osseous lesion in the ankle was operatively excised.

View Article and Find Full Text PDF

Inhibition of the mTOR signaling pathway promotes initiation of autophagy. However, recent studies indicate that autophagy is a self-defense mechanism of cancer cells that are subjected to anti-tumor agents and that blocking autophagy can trigger apoptosis. Here, we examined the effects of an mTOR inhibitor, temsirolimus, on a malignant fibrous histiocytoma (MFH) cell line, Nara-H cells, and the effect of suppressing autophagy on the induction of apoptosis in these MFH cells.

View Article and Find Full Text PDF

A 20-year-old man presented with pain and recurrent hemarthrosis in the right knee. Magnetic resonance imaging of the knee showed a lesion with homogeneous low signal intensity on T1-weighted images and a heterogeneous, low to high signal intensity on T2-weighted images. At arthroscopy, the mass was located between the posterior cruciate ligament and the posterior knee joint capsule.

View Article and Find Full Text PDF

Aim: Expression of mitogen-activated protein kinase (MAPK) signaling and its role in cell proliferation of the bone malignancies, osteosarcoma (OS) and malignant fibrous histiocytoma (MFH) were investigated.

Materials And Methods: Gene expression and protein levels of RAF1 and MEK1/2 in 6 human sarcoma cell lines and 7 surgically obtained OS specimens were assessed by RT-PCR and immunohistochemistry, respectively. MEK inhibitor, U0126 [1,4-diamino-2,3-dicyano-1,4-bis (2-aminophynyltio) butadiene], was used for cell proliferation assays.

View Article and Find Full Text PDF

Ischiogluteal bursitis is an uncommon disorder which can be confused with neoplastic conditions in the buttock. Three cases of ischiogluteal bursitis in a 57-year-old man, a 73-year-old woman and a 73-year-old man are presented. All patients presented with a gradually increasing, painful buttock mass.

View Article and Find Full Text PDF

Background: PKC412, formerly CGP41251, N-benzoylstaurosporine, was initially developed as a selective protein kinase C (PKC) inhibitor, and it preferentially inhibits conventional PKC family members. In this study, the expression of PKCa was examined in human osteosarcoma and MFH cell lines, and the inhibitory effect of PKC412 on the proliferation of the cell lines was evaluated.

Materials And Methods: Three human osteosarcoma cell lines (KTHOS, MG63 and KHOS) and four human MFH cell lines (TNMY1, GBS-1, Nara-F and Nara-H) were used.

View Article and Find Full Text PDF

We present details of a case of intra-tendinous ganglion arising from the long head of the biceps at an unusual location. MRI scans have important implications for surgical planning and treatment. After excision of the ganglion, the tendon remaining could be repaired.

View Article and Find Full Text PDF

Osteosarcoma is a malignant bone tumor that commonly affects adolescents and young adults. In the present study a human osteosarcoma cell line, KTHOS, was established from a primary osteosarcoma lesion in the distal femur of a 16-year-old girl. After 106 passages, the KTHOS cell line retained the biological characteristics of osteosarcoma.

View Article and Find Full Text PDF

Background: Malignant fibrous histiocytoma (MFH) is one of the most common high-grade sarcomas in bone and soft tissue and, due to its chemo-resistance, the prognosis of the disease is poor. ST1571 is a tyrosine kinase inhibitor that was initially developed as a BCR/ABL inhibitor for chronic myeloid leukemia patients. STI571 also selectively inhibits platelet-derived growth factor receptors (PDGFRs) and c-kit.

View Article and Find Full Text PDF

Purpose: Transforming growth factor beta (TGF-beta) is a multifunctional growth factor that variably affects proliferation, differentiation, and extracellular matrix formation. Little information is currently available on the TGF-beta expression in malignant fibrous histiocytoma (MFH). The aims of the present study were to investigate the expression of TGF-beta isoforms and their receptors in human MFH specimens.

View Article and Find Full Text PDF

Background: Heparin-binding epidermal growth factor (HB-EGF), betacellulin (BTC) and epiregulin (EPR) are members of the EGF system and involved in the cell growth of various epithelial malignancies. There have been no reports on the HB-EGF, BTC and EPR expression in mesenchymal malignancies of fibrohistiocytic origin including malignant fibrous histiocytoma (MFH).

Materials And Methods: We investigated the expression of HB-EGF, BTC, EPR and EGF-receptor (EGF-R) in 43 human MFH tissue samples using immunohistochemical techniques.

View Article and Find Full Text PDF

Hepatocyte growth factor (HGF) is a multifunctional cytokine that variably affects cell motility, proliferation, and morphogenesis. Little information is currently available on the HGF and its receptor c-Met expression in malignant fibrous histiocytoma (MFH). We immunohistochemically investigated the HGF and c-Met expression in 43 MFH tissue specimens.

View Article and Find Full Text PDF

We present multimodality imaging features of an ischial tuberosity apophysitis in a 13-year-old boy who was an active baseball pitcher. Roentgenography of the pelvis and computed tomography showed mild irregularity in the inferior margin of the left ischial tuberosity. T1-weighted MRI showed a wide area with low signal intensity in the left ischial body; T2-weighted fat-suppression images showed areas with markedly high signal intensity in the ischial apophysis and body and the surrounding periosteum; contrast-enhanced T1-weighted fat-suppression MRI showed that the ischial body, surrounding periosteum, and origin of the hamstring muscles strongly enhanced; technetium-99m scintigraphic scans showed increased isotope uptake in the entire ischial body.

View Article and Find Full Text PDF

Background: Amphiregulin is a member of the epidermal growth factor (EGF) system and a potent mitogen for various epithelial tissues. Little information, however, is currently available on the amphiregulin and EGF receptor (EGF-R) expression in mesenchymal malignancies of a fibrohistiocytic origin including malignant fibrous histiocytoma (MFH).

Materials And Methods: We investigated the amphiregulin and EGF-R expression in 43 human MFH tissues using immunohistochemical techniques.

View Article and Find Full Text PDF

Two cases of deep-seated neurilemmoma that arose from plantar branches of the posterior tibial nerve and caused chronic heel pain are described. At the initial examination, one case was misdiagnosed as tarsal tunnel syndrome and the other was overlooked as plantar fasciitis; both cases were treated for long periods prior to operation. Deep-seated neurilemmomas in the foot can easily be overlooked and misdiagnosed as tarsal tunnel syndrome or plantar fasciitis because of the rarity, absence of palpable mass, and similarity of symptoms to those of other frequently encountered foot disorders.

View Article and Find Full Text PDF

Osteoblastomas located on the surface of the cortical bone, so-called periosteal osteoblastomas, are extremely rare. We report on a case of periosteal osteoblastoma arising from the posterior surface of the right distal femur in a 17-year-old man. Roentgenographic, computed tomographic, magnetic resonance imaging, and histologic features of the case are presented.

View Article and Find Full Text PDF

Background: Little information is available regarding the expression of platelet-derived growth factor (PDGF) isoforms and their receptors in soft tissue malignant fibrous histiocytoma (MFH).

Materials And Methods: We investigated expression of PDGF isoforms and their receptors (PDGF-R alpha and -R beta) in 43 MFH tissue specimens using immunohistochemical techniques. Furthermore, we examined the correlation of PDGF expression in MFHs with proliferative activity assessed by MIB-1 immunohistochemical staining.

View Article and Find Full Text PDF

Background: Little information is available on the expression of stem cell factor (SCF) and its receptor c-kit in soft tissue tumors of a fibrohistiocytic origin, including malignant fibrous histiocytoma (MFH).

Materials And Methods: We investigated the endogenous expression of SCF and c-kit in 43 MFH tissue samples using immunohistochemical techniques. Furthermore, we examined the correlation of SCF expression in MFHs with proliferative activity assessed by mitotic indices and MIB-1 immunohistochemical staining.

View Article and Find Full Text PDF