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Hajime Umezu

Publications and source records attributed to Hajime Umezu.

At least 19 recordsLinked to original sources
PubMed2006

Osteoinduction with highly purified beta-tricalcium phosphate in dog dorsal muscles and the proliferation of osteoclasts before heterotopic bone formation.

The aim of the study was to examine the chronological histology of osteoinduction of highly purified beta-tricalcium phosphate (beta-TCP) implanted in dog dorsal muscles. Specimens were harvested on days 14, 28, 42, 56, 112 and 168 after implantation, and were analyzed by hematoxylin and eosin (HE) staining, tartrate-resistant acid phosphatase (TRAP) staining, immunohistochemistry, in situ hybridization, and silver impregnation. After day 28, abundant TRAP- and cathepsin K-positive multinucleated cells adhered to beta-TCP, suggesting that these cells are osteoclasts that can resorb beta-TCP. On day 56, new bone was formed and alpha1 chain of type I procollagen mRNA-positive osteoblasts lined the newly formed bone. Silver impregnation showed abundant collagen fibrils within the beta-TCP micropores. These results suggest that micropores function as a storage space for extracellular matrix components, including collagen. Newly formed bone never degenerated in the late stage, suggesting that beta-TCP has good biocompatibility and this material retains the conditions appropriate for osteointegration and bioresorption. In conclusion, beta-TCP has osteoinductivity after implantation in dog dorsal muscles without use of bone marrow cells or osteoinductive cytokines. The appearance of a large number of active osteoclasts precedes new bone formation.

Animals↗
PubMed2006

[A case of primary central nervous system malignant lymphoma developing from the optic chiasma and hypothalamus].

A 63-year-old woman was admitted to our hospital with a 1-month history of visual field defect and reduced bilateral visual acuity. Neurological examination revealed enlargement of bilateral central scotoma and blurred vision, and brain MRI showed masses in the optic chiasma and right hypothalamus on Ti-weighted image with contrast enhancement. Although the patient was treated with high-doses of methylprednisolone four times, the masses spread to the right internal capsule and the vicinity of the right lateral ventricle. An open biopsy was performed and microscopic examination of the sample revealed lymphoplasmacytic lymphoma. Although primary central nervous system lymphoma (PCNSL) developing from the optic chiasma and hypothalamus is rare, PCNSL should be considered in patients with multiple lesions in the optic chiasma and hypothalamus.

Brain Neoplasms↗
PubMed2005

Histological assessment in grafts of highly purified beta-tricalcium phosphate (OSferion) in human bones.

Prominent osteoconductive activity and the biodegradable nature of commercially available beta-tricalcium phosphate (beta-TCP, OSferion) have been documented in animal experiments. We analyzed four cases of involving grafted OSferion in human bone with respect to histological features by routine hematoxylin and eosin staining, silver impregnation, immunohistochemistry and in situ hybridization. OSferion affords early bioresorption by osteoclasts, vascular invasion of macropores and osteoblastic cell attachment on the surface on the ceramic surface 14 days after grafting. Prominent bone formation and direct bone connection between preexisting bone and OSferion were evident 28 days after grafting. Nearly the entire TCP surface was covered by lamellar bone; additionally, active osteoblastic lining and attachment of the osteoclast-like giant cells were not observed 72 weeks after grafting. Silver impregnation revealed the presence of collagen fibrils within probable micropores of OSferion.

Adolescent↗
PubMed2005

A giant subcutaneous leiomyosarcoma arising in the inguinal region.

BACKGROUND: Subcutaneous leiomyosarcoma is a rare condition that accounts for 1% to 2% of all superficial soft tissue malignancies. Approximately 10% of cases arise in the trunk, although the extremities are the most commonly affected. CASE PRESENTATION: We report herein the case of a 31-year-old man with a subcutaneous leiomyosarcoma, measuring 124 x 105 mm, arising in the left inguinal region. A wide local excision (with a resection margin >/= 20 mm) was performed. Histological examination of the resected specimen revealed a leiomyosarcoma with high cellularity and two mitoses per 10 high-power fields. The patient remains well with no evidence of disease 5 years and 8 months after the operation. CONCLUSION: This is the first reported case of subcutaneous leiomyosarcoma arising in the inguinal region and also one of the largest tumors reported. The experience of this case and a review of the English-language literature (PubMed, National Library of Medicine, Bethesda, MD, USA) suggest that a resection margin of >/= 10 mm is recommended when excising this rare tumor.

Journal Article↗
PubMed2005

Establishment and characterization of a novel myxofibrosarcoma cell line.

We established a novel human myxofibrosarcoma cell line NMFH-1 and analyzed it with spectral karyotyping and comparative genomic hybridization (CGH). NMFH-1 cells are composed of two different types of cells, small, spindle-shaped mononuclear cells and bizarre multinucleated giant cells, which were maintained in vitro over 200 passages. Xenografted tumor showed typical features of myxofibrosarcoma, which included bizarre multinucleated giant cells. Cytogenetic analyses revealed complex abnormalities, including a t(17;22)(q2?2;q13), which has been found in dermatofibrosarcoma protuberans. Subsequent reverse-transcription polymerase chain reaction revealed that the cell line did not have the COL1A1-PDGFB gene fusion. Significant gains of the 1q12 approximately q23 and 8q13 approximately qter regions and loss of the 9p21 approximately pter and 13q12 regions often found in MFH were observed by CGH analysis. We investigated the origin of multinucleated giant cells in xenografted tumor through DNA in situ hybridization. In this system, the human-specific Alu sequence and the mouse L1 sequence were used as specific cell markers of identity. In situ hybridization revealed neoplastic proliferation of the multinucleated giant cells of human origin.

Aged↗
PubMed2005

[Medulloblastoma with mandibular metastasis after complete remission of the central nervous system lesions].

A 6-year-old boy presented with headache and vomiting. Brain and spinal MRI demonstrated a large mass in the cerebellar vermis and 4th ventricle and showed thick spinal subarachnoid dissemination. Suboccipital craniotomy was performed and the tumor was totally removed. The histological diagnosis was medulloblastoma. The patient subsequently received craniospinal irradiation, and also received systemic and intrathecal perfusion chemotherapy. Then complete remission was achieved 10 months after operation. Three years later, however, a swelling at the left mandibular angle appeared. A CT scan revealed osteosclerotic lesion. After biopsy was performed, the specimen was detected infiltration of medulloblastoma cells. Bone scintigram showed a single lesion and MRI of brain and spinal cord revealed no recurrence of the central nervous system lesions. He underwent local irradiation and systemic chemotherapy with ICE regimen. This is the rare case of extracranial metastasis following remission of medulloblastoma in childhood.

Antineoplastic Combined Chemotherapy Protocols↗
PubMed2004

Sclerosing epithelioid fibrosarcoma with der(10)t(10;17)(p11;q11).

Sclerosing epithelioid fibrosarcoma is a recently described, rare mesenchymal neoplasm. We report a case of sclerosing epithelioid fibrosarcoma that occurred in the lower leg of a 48-year-old man. The karyotype of the tumor exhibited der(1)t(1;10)(p31;p11), der(10)t(10;17)(p11;q11), and der(17) t(11;17)(?;q11). Rearrangement of 10p11 was also found in one previous reported case of this uncommon tumor.

Chromosome Aberrations↗
PubMed2004

Diagnosis of peripheral nerve sheath tumors around the pelvis.

OBJECTIVE: To distinguish between benign and malignant peripheral nerve sheath tumors around the pelvis. METHODS: A retrospective study of 30 patients with benign and malignant peripheral nerve sheath tumors located around the pelvis was performed. Clinical, imaging and histological features of 19 benign and 11 malignant peripheral nerve sheath tumors around the pelvis were reviewed retrospectively. RESULTS: Nearly all patients exhibited pain at presentation in cases involving both benign and malignant tumors. Although tumor size, duration of symptoms and presence of sensory disturbance possessed little value in differential diagnosis, severe motor weakness was observed exclusively in patients presenting with malignant tumors. On CT or MRI, central enhancement was apparent in 11 of the 19 benign tumors; in contrast, central enhancement was evident in one of the 11 malignant tumors. Fine needle aspiration cytology was performed in 11 tumors; correct diagnosis was achieved in four tumors. Core needle biopsy was performed in five tumors, all of which were correctly diagnosed with no neurological deficits. Immunohistochemically, all benign tumors were diffusely positive for S-100 protein, whereas malignant tumors were negative or focally positive for S-100 protein. Ki-67 index was less than 4% in all benign tumors; additionally, this index was 7-36% in malignant tumors. CONCLUSION: Central enhancement pattern on imaging studies strongly suggests a benign tumor; in contrast, severe motor weakness suggests malignant lesions. Core needle biopsy was reliable with respect to preoperative diagnosis.

Adolescent↗
PubMed2003

Plexiform schwannoma of the forearm.

We report a case of plexiform schwannoma located in the flexor muscles of the forearm in the absence of other signs of neurofibromatosis or schwannomatosis. Magnetic resonance examination revealed a multinodular irregular inhomogeneous mass. Some nodules displayed a peripheral, high intensity rim and a central low intensity (target sign) on T2-weighted images. Pre-operative diagnosis of the rare plexiform schwannoma may be possible with careful imaging examination for the target sign.

Adult↗
PubMed2003

Presacral multiple cellular schwannomas.

STUDY DESIGN: Case report. The authors documented a patient presenting with multiple cellular schwannomas along the sciatic nerve. The patient had no stigmas of neurofibromatosis. Thirteen tumors were resected via both anterior and posterior approaches. OBJECTIVES: To point out that presacral cellular schwannoma can display multiple occurrences. SUMMARY OF BACKGROUND DATA: Cellular schwannoma, which is a well-recognized variant of benign schwannoma, is often misdiagnosed as sarcoma. The tumor is usually a solitary lesion. MATERIALS AND METHODS: Medical history, physical findings, imaging features, and histologic findings were reviewed in a case of multiple cellular schwannomas in the presacral regions. RESULTS: A 39-year-old woman without any evidence of neurofibromatosis underwent removal of presacral multiple tumors along the sacral nerve root. Nineteen years after the surgery, the tumors recurred with multiple fashion. Thirteen tumors were resected via both anterior and posterior approaches. Immunohistochemical analysis of S-100 protein and Ki-67 were beneficial with respect to differentiation of cellular schwannoma from malignant peripheral nerve sheath tumor. CONCLUSIONS: The present case illustrated that multiple cellular schwannomas can develop in nonneurofibromatosis patients.

Adult↗
PubMed2003

Activating Gs alpha mutation at the Arg201 codon in liposclerosing myxofibrous tumor.

Liposclerosing myxofibrous tumor (LSMFT) is a benign fibro-osseous lesion that is characterized by mixture of histologic elements including lipoma, fibroxanthoma, myxoma, ischemic ossification, and fibrous dysplasia (FD)-like features. These tissue components are seen in the original reports of FD; however, the relationship between LSMFT and FD is not clear. Point mutation of the alpha subunit of G protein (Gs alpha), which increases cyclic adenosine monophosphate formation, has been recognized as the cause of McCune-Albright syndrome as well as polyostotic and monostotic FD of bone. Gs alpha mutation at the Arg201 codon in 2 patients of LSMFT was demonstrated in the present study. Although direct sequencing analysis using the fresh-frozen materials could not detect the mutation, the polymerase chain reaction fragmentation length polymorphism (PCR-RFLP) disclosed the missense point mutation Gs alpha at the Arg201 codon in 2 cases involving LSMFT. This result strongly suggests that a subset of LSMFT is a variant form of FD.

Aged↗
PubMed2003

[High-resolution CT findings of pulmonary atypical adenomatous hyperplasia of 5 mm or less in diameter].

OBJECTIVE: To clarify the high-resolution CT(HRCT) findings of pulmonary atypical adenomatous hyperplasia (AAH) of 5 mm or less in diameter. MATERIALS AND METHODS: We evaluated the HRCT findings of 43 histopathologically confirmed AAH of 5 mm or less in diameter in 7 patients who underwent lobectomy for pulmonary adenocarcinoma. For comparison, we also examined the HRCT findings of 13 bronchioloalveolar carcinomas (BAC) of the same size from these patients. RESULTS: We identified 36 of 43 AAH and all 13 BAC on HRCT performed with multidetector-row CT. Thirty-five AAH and 11 BAC showed ground-glass opacity without any high-attenuation component. Margins of 20 AAH were well defined, and 16 were ill defined. In BAC, 11 lesions demonstrated well-defined margins, with only 2 showing ill-defined margins. CONCLUSION: Most AAH lesions of 5 mm or less in diameter are identified as ground-glass opacity on HRCT. Detection of minute ground-glass opacity is important in locating AAH on HRCT.

Adenocarcinoma, Bronchiolo-Alveolar↗
PubMed2002

Histological examination of beta-tricalcium phosphate graft in human femur.

Prominent osteoconductive activity and the biodegradable nature of beta tricalcium phosphate (beta-TCP) for bone grafts in animal experiments has been reported. A new type of beta-TCP has been manufactured at extraordinarily high purity and has been available as potent bone grafting substitute for clinical use. The histological features of grafted beta-TCP in human bone have been analyzed. A 33-year-old female with a bone tumor of the proximal femur underwent curettage and beta-TCP graft under the diagnosis of probable benign fibrous dysplasia. Four weeks later, the proximal femur, including the grafted beta-TCP was resected because of the final diagnosis of the curettaged materials was osteosarcoma. The resected specimen revealed abundant direct new bone apposition on beta-TCP. There was no cartilaginous tissue or enchondral ossification. Bone formation was more prominent in the periphery of the grafted area than in the center. There was a considerable number of osteoclast-like giant cells surrounding the beta-TCP. This case illustrated that highly purified beta-TCP had prominent osteoconductive activity and biodegradable nature in human bone.

Absorbable Implants↗
PubMed2001

Alpha-synuclein immunoreactivity in normal and neoplastic Schwann cells.

Alpha-synuclein is known to play an important role in several neurodegenerative diseases. Moreover, it is expressed in central nervous system neuronal tumors, and another member of the synuclein family, gamma-synuclein, is overexpressed in breast and ovarian carcinomas. However, the expression of alpha-synuclein has not been reported hitherto in the peripheral nervous system (PNS). In the present study, we investigated normal PNS tissue and schwannomas in human postmortem and biopsy samples using both immunocytochemistry and immunoelectron microscopy with antibodies against alpha-, beta- and gamma-synuclein. In normal PNS tissue, Schwann cells, but not axons or myelin, were immunopositive for alpha-synuclein. In schwannomas, almost all of the tumor cells showed diffuse cytoplasmic staining for alpha-synuclein (30 cases). Ultrastructurally, alpha-synuclein immunoreactivity was found in the cytoplasm of normal and neoplastic Schwann cells, in association with the plasma membrane, ribosomes, rough endoplasmic reticulum, small vesicles, Golgi apparatus and the nuclear outer membrane. No beta- or gamma-synuclein immunoreactivity was found in those cells. These results indicate that in the PNS, alpha-synuclein is a useful marker of Schwann cells and that it is not involved in tumorigenesis.

Aged↗
PubMedDate not supplied

Microcystic variant of localized malignant mesothelioma accompanying an adenomatoid tumor-like lesion.

The case of a 70-year-old man with a hitherto undescribed pleural mesothelioma is reported. The tumor was localized in the left lung apex and had invaded the parietal pleura. Histologically, the tumor was characterized by a proliferation of epithelioid cells and the formation of microcysts. The tumor cells were positive for calretinin and vimentin, and possessed abundant microvilli, indicating a mesothelial cell origin for the tumor. A high Ki-67 index and mitotic index, and the recurrence of the tumor after surgery, indicated malignancy. Based on the evidence, we propose that the tumor is a microcystic variant of a localized malignant mesothelioma.

Adenocarcinoma↗