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Search Results: 1 - 10 of 1497 matches for " Akio Sakamoto "
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Transmedullary Decompression for Humeral Diaphysis Solitary Bone Cysts  [PDF]
Akio Sakamoto
Open Journal of Orthopedics (OJO) , 2013, DOI: 10.4236/ojo.2013.32015

Solitary bone cysts are benign, fluid-filled cavities that most often occur in childhood. Several minimally invasive decompression methods have been proposed; however, performing a surgical procedure through the thinned overlying cortex raises the risk of pathological fracture and neurovascular damage, especially in lesions located in the bone diaphysis. We describe a new technique that circumvents these problems: tunneling through the normal cortex and medullary space with a flexible reamer, placing a retrograde medullary nail for cyst decompression.

Atypical Fibroxanthoma
Akio Sakamoto
Clinical Medicine : Oncology , 2008,
Abstract: Atypical fibroxanthoma (AFX) is a nodular dermal ulcerative lesion with a favorable prognosis. AFX most commonly occurs on sun-exposed skin in elderly individuals. AFX is characterized by its association with ultraviolet radiation, not only from a clinical aspect, but also from a molecular aspect. Making a diagnosis of AFX is challenging, and it is important to differentiate it from squamous cell carcinoma and malignant melanoma. Histological features and combined immunohistochemical markers are necessary for a defi nitive diagnosis (i.e., an absence of immunostaining for cytokeratins, S100 and HMB45 in AFX is helpful for excluding both squamous cell carcinoma and malignant melanoma). AFX, as well as MFH (malignant fibrous histiocytoma), is a fi brohistiocytic lesion with myofi broblastic differentiation. AFX is considered to be a different lesion from MFH. AFX and MFH might share the same pathway which determines their morphology. However, they may have different pathways in development which determine their biological behavior.
Mutation analysis of the Gadd45 gene at exon 4 in atypical fibroxanthoma
Akio Sakamoto, Shizuka Akieda, Yoshinao Oda, Yukihide Iwamoto, Masazumi Tsuneyoshi
BMC Dermatology , 2009, DOI: 10.1186/1471-5945-9-1
Abstract: Immunohistochemical expression of Bax was analyzed in 7 cases of AFX, and in 7 cases of benign fibrous histiocytoma (BFH) used as a comparison. The expression pattern of Bax was compared to previously reported p53 and Gadd45 expressions in a correspondent series. Mutation of the Gadd45 gene at exon 4 was also analyzed in AFX.AFX and BFH showed immunoreactivities respectively for Bax (3/7, 0/7), Gadd45 (4/7, 1/7) and p53 (2/7, 0/7). There was no exact correlation between p53 expression and Bax or Gadd45 expression. However, the pattern of expression between Bax and Gadd45 was also the same, with the exception of one case. No mutation of the Gadd45 gene at exon 4 was observed in a series of 6 AFX cases where DNA was available (0/6).These results suggest a possible association between Bax and Gadd45 in AFX, and may refute any possibility of dysfunction of Gadd45 in terms of gene mutation, at least at exon 4 of the Gadd45 gene.Atypical fibroxanthoma (AFX) is a nodular ulcerative lesion arising from the sun-exposed skin of the head and neck, typically in the elderly [1,2]. Solar elastosis associated with UV-radiation has been commonly observed in AFX cases [3]. Association between AFX and ultraviolet (UV) radiation has been suspected. On the other hand, in its less common forms with weakened association with UV, AFX occurs on the extremities and the trunk [1,2]. AFX is composed of spindle, plump, epithelioid and bizarre cells, in various proportions, arranged in haphazard, vaguely fascicular or storiform patterns. These histological features of AFX mimic those of high-grade sarcoma, such as malignant fibrous histiocytoma or leiomyosarcoma [2,4], which occurs deep within soft tissue.The tumor-suppressor protein p53 is a transcriptional activator which is involved in cell-cycle control, DNA repair, apoptosis and chromosome/genome instability. UV-induced p53 gene mutations occurring at dipyrimidine sites have been demonstrated in AFX, suggesting a central role for UV radiat
Establishment of an animal model of a pasteurized bone graft, with a preliminary analysis of muscle coverage or FGF-2 administration to the graft
Tatsuya Yoshida, Akio Sakamoto, Nobuaki Tsukamoto, Koichi Nakayama, Yukihide Iwamoto
Journal of Orthopaedic Surgery and Research , 2009, DOI: 10.1186/1749-799x-4-31
Abstract: Forty pasteurized intercalary bone grafts of the Wistar rat femur treated at 60°C for 30 min were reimplanted and stabilized with an intramedullary nail (1.1 mm in diameter). Some grafts were not covered by muscle after the implantation, so that they could act as a clinical model for wide resection, and/or these were soaked with FGF-2 solution prior to implantation. The grafts were then divided into 3 groups, comprising 12 grafts with muscle-covering but without FGF-2 (MC+; FGF2-), 12 grafts without muscle-covering and without FGF-2 (MC-; FGF2-) and 16 grafts without muscle covering but with FGF-2 (MC-; FGF2+).At 2 weeks after grafting, the pasteurized bone model seemed to be successful in terms of eliminating living cells, including osteocytes. At 4 weeks after grafting, partial bone incorporation was observed in half the (MC+; FGF2-) cases and in half the (MC-; FGF2+) cases, but not in any of the (MC-; FGF2-) cases. At 12 weeks after grafting, bone incorporation was seen in 3 out of 4 in the (MC+; FGF2-) group (3/4: 75%) and in 3 out of 8 in the (MC-; FGF2+) group (3/8: 38%). However, most of the grafted bones without FGF-2 were absorbed in all the cases, massively, regardless of whether there had been muscle-covering (MC+; FGF2-; 4/4: 100%) or no muscle-covering (MC-; FGF2-; 4/4: 100%), while bone absorption was noted at a lower frequency (2/8: 25%) and to a lower degree in the (MC-; FGF2+) group.In conclusion, we have established an animal pasteurized bone graft model in rats. Pasteurized bone was able to maintain bone induction ability. Despite the low number of cases in each group, the results of each group suggest that muscle-covering has an effect on bone incorporation, but that it is not able to prevent bone absorption to the pasteurized bone. However, an application of FGF-2 may have a positive effect on bone incorporation and may be able to prevent bone absorption of the graft in cases of pasteurized bone graft.Pasteurized bone grafting is a method of hea
Myxoid liposarcoma with negative features on bone scan and [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography
Sakamoto Akio,Fukutoku Yoshiaki,Matsumoto Yoshihiro,Harimaya Katsumi
World Journal of Surgical Oncology , 2012, DOI: 10.1186/1477-7819-10-214
Abstract: Background Myxoid liposarcoma occurs in middle age, and is characterized by extrapulmonary metastasis, including bone metastasis. Bone scans and [18F]-2-fluoro-2-deoxy-D-glucose-positron emission tomography (FDG-PET) are widely used for assessment of tumor extension, including vertebral metastasis. However, both methods have a low positive rate with regard to vertebral metastasis arising from myxoid liposarcoma. This is particularly true for bone scans for intramedullary lesions that have no cortical involvement. Case presentation We present the case of a 53-year-old male with myxoid liposarcoma in the leg. He had been treated for multiple metastases over a ten-year period, and was experiencing back pain due to a pathological fracture in the second lumbar vertebra (L2). Magnetic resonance imaging of all the vertebrae showed abnormal signal intensity suggestive of metastasis in eight vertebrae, and revealed extraskeletal extension in three vertebrae. Bone scans and FDG-PET were negative except for the L2 fracture which was indicated on a bone scan. Conclusions Both bone scans and FDG-PET can be negative in cases of vertebral metastasis that arise from myxoid liposarcoma, even when extraskeletal extensions are present. Similarly, even a fractured vertebra may not always be visible on FDG-PET.
Nonossifying fibroma presenting as an aneurysmal bone cyst: a case report
Sakamoto Akio,Ishii Takeaki,Oda Yoshinao,Iwamoto Yukihide
Journal of Medical Case Reports , 2012, DOI: 10.1186/1752-1947-6-407
Abstract: Introduction Nonossifying fibroma is a common fibrous bone lesion in children that occurs in the metaphysis of the long bones of the lower extremities. The lesion rarely leads to aneurysmal bone cyst, which is characterized as a blood-filled space. Case presentation We present the case of a 13-year-old Japanese boy with a complaint of discomfort in the thigh and a small, well-defined, osteolytic lesion with cortical thinning located in the medullary space of the distal diaphysis of the femur. At 10-month follow-up, the size of the lesion had increased. Gadolinium-enhanced magnetic resonance imaging failed to detect any solid area. Curettage and bone graft were performed and confirmed a blood-filled cystic lesion. The pathological diagnosis of the cyst wall was that of nonossifying fibroma, suggesting aneurysmal bone cyst as a secondary change. An aneurysmal bone cyst is rarely found secondary to nonossifying fibroma, and the diaphyseal location is atypical for nonossifying fibroma, both of which made diagnosis challenging. Conclusion The current case is a reminder to clinicians that, although rare, nonossifying fibroma can be associated with aneurysmal bone cyst, and both can occur in the diaphysis of long bones.
Clinical outcome for patients with dedifferentiated chondrosarcoma: a report of 9 cases at a single institute
Yokota Kazuya,Sakamoto Akio,Matsumoto Yoshihiro,Matsuda Shuichi
Journal of Orthopaedic Surgery and Research , 2012, DOI: 10.1186/1749-799x-7-38
Abstract: Background Dedifferentiated chondrosarcomas consist of two distinguishable components: low-grade chondrosarcoma components and high-grade dedifferentiated components. Materials and methods Nine cases (4 males, 5 females) of dedifferentiated chondrosarcoma were treated in our institute. The average age was 58.6 (range, 37–86) years. The tumor location was the long bone in 7 cases (femur, n=5; humerus, n=1; tibia, n=1) and the pelvic bone in 2 cases. The average time from appearance of symptoms to treatment was 9.4 (range, 1–40) months. Results and discussion On plain radiographs, matrix mineralization was seen in all 9 cases (100%). Bone destruction was observed in 5 of 9 cases (56%), while pathological fracture was seen in one femur case (11%). Lung metastasis was observed in all cases (initially in 5 cases; during the treatment course in 4 cases). Surgery was performed in 8 cases, with local recurrence occurring in 2 of those cases (time to recurrence, 2 and 10 months). Chemotherapy was administered in 4 cases, but did not result in significant improvement. All 9 cases died of lung metastases, with a median survival time of 10 (range, 3.4-18.8) months. The presence of initial metastasis at diagnosis was a significant unfavorable prognostic factor. Conclusion The prognosis of dedifferentiated chondrosarcoma is dismal. With the lack of convincing evidence of the benefit of chemotherapy, complete surgical excision is the initial recommended treatment.
Insufficiency Fracture in the Para-Acetabulum, with Features Mimicking Those of a Malignant Bone Tumor
Akio Sakamoto,Takuaki Yamamoto,Kazuhiro Tanaka,Shuichi Matsuda
Clinical Medicine : Case Reports , 2008,
Abstract: Para-acetabular insufficiency fractures are rare and exceedingly difficult to diagnose without a high index of suspicion, since the images mimic those of bone tumors. We herein present the case of a 55-year-old woman who suffered from hip pain with subacute onset. She had undergone a hysterectomy-ovariectomy due to endometriosis when she was 41 years old. Her bone mineral density was normal due to supplemental treatment with female hormones. About 3 months after onset, she was referred to our institute with a diagnosis of pelvic bone tumor. Plain radiographs and computed tomography showed irregular osteosclerosis in the para-acetabulum. Bone scintigraphy demonstrated uptake in the para-acetabulum. Magnetic resonance imaging showed abnormal signal with low-signal intensity on T1-weighted images and high-signal intensity on T2-weighted images throughout the entire hemipelvic bone. Since the pain continued for more than 3 months, open biopsy was undertaken and the lesion was found to be non-neoplastic. Six months after onset, the pain disappeared. The clinical course suggested a diagnosis of insufficiency fracture in the para-acetabulum. Para-acetabular insufficiency fractures should always be considered in cases of hip pain, even in patients with prolonged symptoms.
Malignant Triton Tumor in the Abdominal Wall: A Case Report  [PDF]
Yoshiyuki Kitamura, Koichiro Abe, Shingo Baba, Takuro Isoda, Yasuhiro Maruoka, Yoshio Matsuo, Yuichiro Kubo, Akio Sakamoto, Hiroshi Nishimura, Masayuki Sasaki, Hiroshi Honda
Advances in Molecular Imaging (AMI) , 2013, DOI: 10.4236/ami.2013.32002

Malignant triton tumor (MTT) is a rare variant of malignant peripheral nerve sheath tumor (MPNST) with rhabdomyosarcomatous differentiation. We report the case of a 54-year-old male without a history of neurofibromatosis type 1 (NF1) who had a growing abdominal wall tumor diagnosed as MTT. Computed tomography (CT), magnetic resonance imaging (MRI) and 2-[F-18]-fluoro-2-deoxy-D-glucose positron emission tomography/CT (FDG-PET/CT) were performed. The MRI and FDG-PET/CT indicated that the lateral component of the tumor was composed of many proliferative cells, corresponding to the histopathological finding of a cellular proliferation of spindle-shaped cells. In light of this case and previous reports, it is apparent that FDG-PET/CT is a helpful tool for distinguishing MTT from benign peripheral nerve sheath tumor.

Effectiveness of communication campaign on iron deficiency anemia in Kyzyl-Orda region, Kazakhstan: a pilot study
Ainur Baizhumanova, Akio Nishimura, Katsuki Ito, Junichi Sakamoto, Nailya Karsybekova, Igor Tsoi, Nobuyuki Hamajima
BMC Blood Disorders , 2010, DOI: 10.1186/1471-2326-10-2
Abstract: The subjects of the study were women aged 15-49 years and children aged 2-14 years. The study was carried out in urban and rural areas of Kyzyl-Orda region in 2003 before (March) and after (December) the campaign. Blood samples were collected in order to measure hemoglobin and serum ferritin. In March 80 women and 57 children in the urban area, and 41 women and 41 children in the rural area, participated in the IDA testing. The corresponding participants in December numbered 62, 52, 52, and 57, respectively. The impacts of the communications and information received by participants during the campaign was surveyed with a questionnaire for 195 women in March and 198 women in December including some who participated in the IDA testing.In March, the prevalence of anemia was 52.0% among 121 women and 58.1% among 98 children, and those with low iron reserve were 63.6%, 49.1% and IDA 40.5%, 11.0%, respectively. In December, the prevalence of anemia had significantly decreased among rural women (from 65.9% to 48.0%, p < 0.05) and among urban children (from 63.1% to 11.5%, p < 0.001). The prevalence of iron deficiency was significantly reduced among the children (from 51.1% to 24.8%, p < 0.001). IDA prevalence was meaningfully decreased among women in urban and combined areas (from 37.5% to 15.0% and 40.5 to 14.8%, respectively, p < 0.001) and among urban children (from 7.1% to 2.1%, p < 0.05). The surveys found that most women knew about IDA and its prevention and that the numbers were similar both in March and in December. The knowledge of the anti-anemic effect of wheat fortified flour improved significantly over the period of the campaign among women both in urban (from 48.5% to 80.9%, p < 0.001) and rural (from 69.8% to 88.6%, p < 0.001) areas.The study demonstrated that the communication campaign before implementation of WFF program was effectively carried out, giving a biological impact on hematological indices.Iron deficiency anemia (IDA) is the most common and wide
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