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Biomedical subjects

Takashi Tsuchiya

Publications and source records attributed to Takashi Tsuchiya.

17 recordsLinked to original sources
PubMed2006

Calcaneal insufficiency fracture in a child with osteosarcoma after chemotherapy and limb-sparing surgery.

We report a rare case of a calcaneal insufficiency fracture in an 11-year-old boy with an osteosarcoma of the right proximal tibia. After one course of neoadjuvant chemotherapy for 4 months, we performed limb-sparing surgery. The knee joint was replaced with a custom-made endoprosthesis and the knee extensor mechanism was reconstructed with a medial gastrocnemius muscle flap. Seven months postoperatively, he complained of pain in the right foot and a plain radiograph revealed a calcaneal insufficiency fracture. Osteoporosis induced by chemotherapy and change of forces transmitted to the calcaneus after reconstruction with a gastrocnemius muscle flap might contribute to this fracture. It is important to be aware of the rare clinical entity of insufficiency fracture for making an early diagnosis and for differentiating them from pathological fractures associated with malignancy.

Antineoplastic Agents↗
PubMed2006

Large benign rheumatoid nodules of the trunk in an elderly patient: radiologic appearance mimicking a soft-tissue sarcoma.

An 80-year-old woman without any evidence of rheumatoid arthritis presented with two large (maximum diameter: 6 cm and 7 cm), rapidly growing, rubbery nodules on the trunk. Although the clinical and radiological appearance suggested malignancy, the nodules were pathologically identical to rheumatoid nodules in rheumatoid arthritis, and the nodules regressed spontaneously. The final diagnosis was benign rheumatoid nodules. Recognition of this rare clinical entity is important to avoid unnecessary examination and treatment.

Aged, 80 and over↗
PubMed2006

A maximum likelihood approach to density estimation with semidefinite programming.

Density estimation plays an important and fundamental role in pattern recognition, machine learning, and statistics. In this article, we develop a parametric approach to univariate (or low-dimensional) density estimation based on semidefinite programming (SDP). Our density model is expressed as the product of a nonnegative polynomial and a base density such as normal distribution, exponential distribution, and uniform distribution. When the base density is specified, the maximum likelihood estimation of the polynomial is formulated as a variant of SDP that is solved in polynomial time with the interior point methods. Since the base density typically contains just one or two parameters, computation of the maximum likelihood estimate reduces to a one- or two-dimensional easy optimization problem with this use of SDP. Thus, the rigorous maximum likelihood estimate can be computed in our approach. Furthermore, such conditions as symmetry and unimodality of the density function can be easily handled within this framework. AIC is used to choose the best model. Through applications to several instances, we demonstrate flexibility of the model and performance of the proposed procedure. Combination with a mixture approach is also presented. The proposed approach has possible other applications beyond density estimation. This point is clarified through an application to the maximum likelihood estimation of the intensity function of a nonstationary Poisson process.

Data Interpretation, Statistical↗
PubMed2005

Long-term prevention of skeletal complications by pamidronate in a patient with bone metastasis from endometrial carcinoma: a case report.

INTRODUCTION: Bisphosphonates are an effective treatment for bone metastases from breast cancer. However, it is unclear whether they are effective for bone metastases from endometrial carcinoma. CASE: A 70-year-old woman previously treated for endometrial carcinoma was referred to our hospital due to osteolytic destruction of the left ischial tuberosity. Technetium-99m-HMDP bone scintigraphy revealed abnormal uptake in the ischium. Biopsy revealed a metastatic bone tumor, but computed tomography scans did not show general metastatic spread. The patient received intravenous administration of pamidronate and three cycles of chemotherapy (epirubicin + paclitaxel + carboplatin). Three years later, the bone lesion showed prominent sclerotic changes with no evidence of disease recurrence radiologically. CONCLUSION: Pamidronate may prevent skeletal complications in selected patients with bone metastasis due to endometrial carcinoma.

Aged↗
PubMed2005

Methylation status of EXT1 and EXT2 promoters and two mutations of EXT2 in chondrosarcoma.

Germline mutation and functional loss of EXT1 or EXT2 are commonly found in multiple osteochondromas and predispose to the development of chondrosarcoma. Mutations of EXT1 and EXT2 have rarely been detected in sporadic secondary chondrosarcomas from osteochondroma; these frequently display loss of heterozygosity at the EXT1 and EXT2 loci, but primary chondrosarcomas typically do not. To evaluate promoter methylation (which is an epigenetic gene silencing mechanism) of EXT1 and EXT2, we performed methylation-specific polymerase chain reaction (PCR) for 20 chondrosarcoma cases (12 primary, 3 secondary to osteochondroma, 2 secondary to enchondromatosis, 2 extraskeletal ordinary, and 1 clear cell) and in five cell lines. In addition, mutation analysis of the EXT1 and EXT2 coding regions was performed using PCR-single-strand conformation polymorphism and sequencing analysis for 12 of the 20 chondrosarcoma cases (8 primary, 1 secondary to enchondromatosis, 1 secondary to osteochondroma, and 2 extraskeletal ordinary) and five cell lines. Promoter methylation of EXT1 and EXT2 was not detected in any of the cases, and both EXT1 and EXT2 were expressed in all cell lines. Two missense mutations in EXT2 (D227E and R299H) were detected among the chondrosarcoma cases. When considering tumor development in primary chondrosarcoma, we should include mutations in EXT2, along with the status of other members of the EXT gene family.

5' Untranslated Regions↗
PubMed2005

Mode of progression of intraductal papillary-mucinous tumor of the pancreas: analysis of patients with follow-up by EUS.

BACKGROUND: We investigated the mode of progression of intraductal papillary-mucinous neoplasm of the pancreas (IPMN) in patients who underwent follow-up in order to elucidate the characteristics of malignancy and to establish an effective treatment strategy. METHODS: Fifty-one patients with IPMN (branch-duct type, 47; main-duct type, 4) who had undergone follow-up study by endoscopic ultrasonography (EUS) were included (mean follow-up duration, 41.0+/-32.3 months; average number of EUS examinations performed during follow-up, 4.4). Chronological changes in EUS findings and histological findings of resected specimens were evaluated. RESULTS: Of the patients with the branch-duct type, only 2% showed enlargement of the dilated branches. In the main-duct-type group, an increase in size of the main pancreatic duct (MPD) was observed in 75% of the patients. In 14 patients with papillary protrusions, an increase in size and lateral spread was observed in 71% and 43%, respectively. No patients developed invasive cancer. In 15 patients who had thick septum-like structures (TSS), the development of papillary protrusions and that of invasive cancer were observed in 53% and 13%, respectively. Twenty-nine patients who had thin septum-like structures showed no change. Two patients with dense multilocular large cysts and TSS developed invasive cancer without change in the cystic lesions. One patient developed carcinoma with multifocal stromal invasion. CONCLUSIONS: Patients with branch-duct type IPMNs without papillary protrusions or TSS are not immediate candidates for surgery. Those who have small papillary protrusions have a benign course. It is recommended that patients with the large branch-duct type with TSS should undergo surgery. Attention should be paid to the entire pancreas when performing follow-up examinations in patients with branch-duct type IPMN, as invasive ductal adenocarcinoma can develop at a site in the pancreas different from that of the IPMN.

Adenocarcinoma, Mucinous↗
PubMed2004

Deep venous thrombosis during neoadjuvant chemotherapy in a patient with osteosarcoma: a case report.

A 29-year-old man with an osteosarcoma of the left distal femur developed asymptomatic deep venous thrombosis (DVT) during neoadjuvant chemotherapy. The thrombotic event occurred in the left common iliac vein and was revealed by pelvic computed tomography (CT). We successfully performed a limb salvage operation with placement of a permanent inferior vena cava filter. The thrombus spontaneously regressed without thrombolytic therapy after surgery. We should consider DVT in patients with musculoskeletal sarcomas who are under long-term hospitalization and immobilization associated with not only surgery but also chemotherapy. To screen for both metastasis and DVT, we recommend contrast-enhanced whole-body CT, including scans of the pelvis.

Adult↗
PubMed2003

Dendritic cell and effector cell infiltration in soft tissue sarcomas with reactive lymphoid hyperplasia.

The lymph node is the site of antigen presentation, and dendritic cells are sentinels for anti-tumor immunity. However, little is known about the histological features of lymph nodes and dendritic cells in soft tissue sarcomas. The reactive lymph node and infiltration of dendritic cells or effector cells were studied histologically in 10 soft tissue sarcomas with reactive lymphoid hyperplasia. The cases included four malignant fibrous histiocytomas, two malignant peripheral nerve sheath tumors, one synovial sarcoma, one epithelioid sarcoma, one malignant granular cell tumor, and one liposarcoma. The proportions of the T zone, lymphoid follicle, and lymphoid sinus (which was occupied by cells immunopositive for antibodies against CD3, CD20, or CD68) were 33.4% +/- 11.0%, 6.1% +/- 4.9%, and 13.5% +/- 6.5%, respectively. T zone hyperplasia was observed in all cases, and sinus histiocytosis was found in four. The proportion of the T zone in regional lymph nodes of soft tissue sarcoma patients was significantly higher than that in adult autopsy cases without a cancer history. CD8-, TIA-1-, or granzyme B-positive effector cells were found in each sarcoma tissue. Whereas CD1a-positive dendritic cells were not detected, S-100 protein-positive or CD83-positive dendritic cells were observed in five sarcoma tissues. The coefficient correlation between the numbers of effector cells and dendritic cells positive for CD83 or S-100 protein were demonstrated. Although this is a preliminary report, the present study demonstrated that some soft tissue sarcoma patients showed reactive lymphoid hyperplasia. Furthermore, the association between the infiltration of dendritic cells and that of effector cells was observed in patients with soft tissue sarcomas.

Adolescent↗
PubMed2003

A versatile route to 3-benzoheteroepines containing group 15 and 16 heavier elements involving several novel ring systems, and their thermal stabilities.

The C-unsubstituted 3-benzoheteroepines (2a-g) containing group 15 (P, As, Sb, and Bi) and group 16 (S, Se, and Te) heavier elements were prepared by the reaction of the corresponding metal reagents with (Z,Z)-o-bis(beta-lithiovinyl)benzene (5) which was derived in two steps from a common o-phthalaldehyde (3). The heteroepines (2) thus obtained were thermally labile towards heteroatom extrusion, and their half-lives on heating estimated from (1)H-NMR spectral analysis showed that the 3-benzoheteroepines (2) were far less stable than the corresponding 1-benzoheteroepines (1). The 2,4-bis(trimethylsilyl)-3-benzoheteroepines (17) containing Sb, Bi, and Te were also prepared from o-diiodobenzene (9) in 6 steps and were found to be more stable than the corresponding C-unsubstituted heteroepines (2).

Chemical Phenomena↗
PubMed2003

Synovial sarcoma with massive ossification--a case report.

Synovial sarcoma with extensive osteoid production is rare. We report a case of synovial sarcoma of monophasic type with massive ossification. The diagnosis was confirmed by reverse-transcripitase polymerase chain reaction (RT-PCR). The patient was an-81-year-old woman with recurrent synovial sarcoma in her right knee. The tumor was primarily excised in 1989. It recurred and was removed again in 1996. However, in 1999 a painful mass appeared in the same site. Preoperative plain radiography and computed tomography revealed a 5 x 5 cm soft tissue mass with extensive ossification in the medial side of the right knee joint. The tumor was widely excised in 2000. Soft X-ray examination revealed a trabecular pattern of ossification in the excised tumor. Microscopically the tumor was composed of hypercellular spindle cells with fascicular arrangement with prominent ossification but no epithelial component. The tumor cells were positive for vimentin and focally positive for cytokeratin. The tumor expressed a sequence of SYT-SSX1 fusion gene transcript demonstrated by RT-PCR. Twelve years long survival of the present case without metastasis in spite of repeated recurrence suggests a better prognosis of synovial sarcomas with ossification.

Aged↗
PubMed2002

Analysis of genetic and epigenetic alterations of the PTEN gene in gastric cancer.

The PTEN tumor suppressor gene on 10q23.3, responsible for the Cowden and Bannayan-Zonana syndromes, encodes a dual-specificity phosphatase able to dephosphorylate both tyrosine phosphate and serine/threonine phosphate residues. Mutational inactivation of PTEN has been reported in various malignancies, including endometrial cancers, ovarian cancers, and glioblastomas. In this study, we investigated PTEN gene mutations in 10 gastric cancer cell lines and 58 primary gastric cancers by polymerase chain reaction single strand conformation polymorphism (PCR-SSCP). Hypermethylation of promoter region CpG islands, an alternative mechanism of gene inactivation to coding region mutations, was also evaluated by methylation specific PCR (MSP). Only one (1.7%) of the 58 primary tumors carried a somatic 5-bp deletion in intron 7 of PTEN, which did not alter the mRNA sequence, and no mutations were detected in any of the cell lines. Similar levels of PTEN mRNA expression were observed in all cell lines and primary tumors studied by RT-PCR, and PTEN promoter CpG islands remained unmethylated. Therefore, we conclude that PTEN does not participate in gastric carcinogenesis as a tumor suppressor gene.

Adenocarcinoma↗
PubMed2002

Promoter methylation status of E-cadherin, hMLH1, and p16 genes in nonneoplastic gastric epithelia.

Silencing of tumor suppressor and tumor-related genes by hypermethylation at promoter CpG islands is one of the major events in human tumorigenesis. Promoter methylation is also present in nonneoplastic cells as an age-related tissue-specific phenomenon that precedes the development of neoplasia. To clarify the significance of promoter methylation in nonneoplastic gastric epithelia as a precancerous signal, we investigated promoter methylation status of E-cadherin, hMLH1, and p16 genes in nonneoplastic cells of various organs obtained at autopsy, and compared the results with those of nonneoplastic epithelia of a cancerous stomach. Methylation of these genes was not seen in nonneoplastic cells of organs from people who were 22 years and younger (0%, 0 of 6). In contrast, E-cadherin and p16 were methylated in nonneoplastic gastric epithelia of persons who were 45 years or older. The numbers were 86% (12 of 14) and 29% (4 of 14), respectively. E-cadherin methylation occurred preferentially in the intestines, whereas p16 methylation was almost restricted to the stomach. For samples obtained from patients with stomach cancer, methylation was frequently observed in both neoplastic and corresponding nonneoplastic gastric epithelia: 47% (44 of 94) and 67% (63 of 94) for E-cadherin, 32% (30 of 94) and 24% (23 of 94) for hMLH1, and 22% (21 of 94) and 44% (41 of 94) for p16, respectively. hMLH1 methylation was not seen in nonneoplastic gastric epithelia from autopsy samples but occurred significantly in samples from nonneoplastic tissues of individuals with stomach cancer. Therefore, detection of hMLH1 methylation in nonneoplastic gastric epithelia may be useful for screening patients who may be at risk of developing gastric cancer.

Adaptor Proteins, Signal Transducing↗
PubMed2002

E-cadherin expression in follicular carcinoma of the thyroid.

Follicular carcinoma (FC) of the thyroid is distinguished from follicular adenoma (FA) by confirmation of invasion or metastasis. However, it is still unknown how FC acquires the potential for invasion or metastasis. Twenty early FC (pT1 and pT2) were analyzed for immunohistochemical E-cadherin (E-CD) expression. Four of four (100%) widely invasive FC showed reduced E-CD expression, whereas only two of 16 minimally invasive FC showed reduced expression. In most of the minimally invasive FC, both E-CD and beta-catenin were expressed on cell-cell boundaries, even in areas where capsular invasion occurred. These results suggest that the mechanism of invasion may be different between widely invasive FC and minimally invasive FC, and that E-CD is probably responsible for the invasion of widely invasive FC. Analysis of methylation of the E-CD gene promoter using the methylation-specific polymerase chain reaction (MSP) method revealed no methylated alleles in the DNA from FC.

Adenocarcinoma, Follicular↗
PubMed2002

Magnetic resonance imaging characteristics of bizarre parosteal osteochondromatous proliferation of the hand: a case report.

Bizarre parosteal osteochondromatous proliferation (BPOP) is a reactive lesion of cortical bone. A case of fifth metacarpal BPOP with intramedullary inflammatory extension is shown by magnetic resonance imaging. Histologically the intramedullary extension showed fibrosis with inflammatory cell infiltration. The surrounding adipose tissue showed fibrosis, focal inflammatory cell infiltration, and vascular proliferation. It is important to recognize that BPOP can bear radiologic resemblance to malignant lesions or osteomyelitis when there is an intramedullary inflammatory extension. Preservation of cortical bone under the osteocartilaginous mass on T1-weighted magnetic resonance imaging, and homogenous intramedullary enhancement with gadolinium diethylenetriamine pentaacetic acid (Gd-DTPA), can be helpful for distinguishing BPOP from malignant lesions.

Aged↗
PubMedDate not supplied

Hibernomas show intense accumulation of FDG positron emission tomography.

We present 2 cases of hibernoma. Positron emission tomography using the glucose analog [18F]fluoro-2-deoxy-d-glucose (FDG) of 2 patients with hibernoma showed intense accumulation. Standardized uptake values (SUVs) in these patients were 11.93 and 26.74, values much higher than the SUVs reported in published studies of liposarcomas. Standardized uptake values of FDG positron emission tomography may thus be able to differentiate hibernomas from liposarcomas.

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