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Biomedical subjects

Tetsuo Maeda

Publications and source records attributed to Tetsuo Maeda.

At least 19 recordsLinked to original sources
PubMed2006

Distant metastasis of prostate cancer: early detection of recurrent tumor with dual-phase carbon-11 choline positron emission tomography/computed tomography in two cases.

Several types of recurrence may be detected by radiologic assessment after treatment in patients with prostate cancer. However, early detection of distant metastasis using positron emission tomography has so far never been published. We report two patients who underwent hormone therapy or surgical resection for prostate cancer. They developed distant metastases which were detected on whole body [C-11] choline positron emission tomography/computed tomography with significant elevation of serum PSA level. In one patient, recurrent tumor of the supraclavicular node (6 mm) diminished in size after subsequent hormone therapy. Surgical resection of recurrent tumor of the lung (12 mm) was performed in the other patient, the pathology of which confirmed the metastatic adenocarcinoma derived from the prostate. The recurrent tumor can be correctly detected by dual-phase whole body [C-11] choline positron emission tomography/computed tomography.

Adenocarcinoma↗
PubMed2006

Identification of amino-terminal region of adiponectin as a physiologically functional domain.

Adiponectin is an abundant adipose-specific protein, which acts as an anti-diabetic, anti-atherogenic, and anti-inflammatory adipokine. Although recent advances in the field of adiponectin have been made by the identification of adiponectin receptors and by the understanding about relationship between its multimerization and functions, detailed molecular background remains unclear. Our established anti-human adiponectin antibodies, ANOC 9103 and ANOC 9104, blocked some adiponectin functions such as the growth inhibition of B-lymphocytes on stromal cells and the inhibition of acetylated LDL uptake in macrophages, suggesting that they may recognize important functional regions of adiponectin. As a result of epitope mapping based on the ability to bind to the deleted adiponectin mutants, we identified that these antibodies recognize amino-terminal region of adiponectin before the beginning of the collagen-like domain. Notably, a peptide fragment (DQETTTQGPGVLLPLPKGACTGWMA) corresponding to amino acid residues 17-41 of human adiponectin could bind to restricted types of cells and block adiponectin-induced cyclooxygenase-2 gene expression and prostaglandin E2 production in MS-5 stromal cells. Moreover, the deletion of its amino-terminal region reduced the abilities to inhibit not only collagen-induced platelet aggregation but also diet-induced hepatic steatosis. These data indicate that amino-terminal region of adiponectin is a physiologically functional domain and that a novel receptor, which recognizes amino-terminal region of adiponectin, may exist on some types of cells. Further investigations will contribute to the understanding of molecular mechanisms about adiponectin functions as well as to the designing of novel strategies for the treatment of patients with insulin-resistance, vascular dysfunction, and chronic inflammation.

Adiponectin↗
PubMed2006

CT and MRI findings in KIT-weak or KIT-negative atypical gastrointestinal stromal tumors.

The large majority of gastrointestinal stromal tumors (GIST) can be diagnosed on the basis of KIT immunoreactivity. However, some atypical tumors show weak or negative KIT expression. We studied the imaging characteristics of atypical GIST, reviewing CT and MRI findings in ten patients (eight men, two women; mean age 59 years) with atypical GIST. Radiological studies were evaluated by two radiologists by consensus and included CT and MR imaging in all patients. Pathological diagnoses were made from surgery and confirmed by the polymerase-chain reaction (PCR) to amplify both exons of the c-kit gene and PDGFRA gene. The CT and MR examinations revealed a heterogeneous mass of the stomach containing cystic regions and soft tissue elements in all cases. All lesions were extraluminal masses and had an exophytic epicenter. On T1-weighted MR images soft tissue elements of the tumors were of homogeneously low- (n=3) or iso-signal intensity (n=7) compared with the liver parenchyma. On fast spin-echo T2-weighted MR images soft tissue elements of all tumors showed cystic regions of significantly high signal intensity interspersed with septumlike structures of low signal intensity. All lesions exhibited homogeneously (n=4) or heterogeneously (n=6) mild to moderate enhancement of soft tissue elements. Despite the relatively small number of patients CT and MRI findings of atypical GIST are a submucosal mass with soft tissue elements and cystic regions.

Aged↗
PubMed2006

A case of ganglioneuroma presenting abnormal FDG uptake.

We report a case of ganglioneuroma with abnormal 18F-fluorodeoxyglucose (FDG) uptake. A 26-year-old woman presented to the hospital with a slowly growing abdominal tumor without symptoms. She was diagnosed with neuroblastoma in childhood and treated by surgery and chemotherapy. Computed tomography (CT) revealed huge retroperitoneal tumors and fused 18F-fluorodeoxyglucose positron emission tomography (FDG-PET)/CT image showed abnormal accumulation of FDG in tumors with maximal standardized uptake value of 2.02. Considering her past history, ganglioneuroma matured from neuroblastoma was considered, the most likely diagnosis. However, a second primary malignant tumor, such as malignant peripheral nerve sheath tumor arising in ganglioneuroma, could not be ruled out. Then, an excisional biopsy was performed and the diagnosis of mature ganglioneuroma was made. Pathological investigation may be needed to differentiate ganglioneuroma from other malignant tumors and, therefore, FDG-PET/CT findings can be helpful for biopsy planning.

Abdominal Neoplasms↗
PubMed2006

Diaphyseal medullary stenosis with pleomorphic malignant fibrous histiocytoma of the bone: 99mTc hydroxymethylenediphosphonate and 201Tl chloride scintigraphy findings.

Diaphyseal medullary stenosis (DMS) is an extremely rare hereditary bone dysplasia, which was first described by Arnold in 1973. DMS has a high incidence of pleomorphic malignant fibrous histiocytoma (MFH). In this paper, we report the imaging findings of DMS with pleomorphic MFH of the bone, mainly describing 99mTc hydroxymethylenediphosphonate (HMDP) and thallium-201 (201Tl) chloride scintigraphy findings. On 99mTc HMDP scintigraphy, focal increased uptake area of the right femur corresponded to the area of bone marrow invasion of the tumor and bone infarction. The mechanism of the uptake of 99mTc HMDP to the extraosseous lesion was not clear. On 201Tl chloride scintigraphy, the increased uptake of the periphery of the mass seemed to reflect the aggressiveness of invasion and the cellularity.

Adult↗
PubMed2006

CT and MRI features of low-grade fibromyxoid sarcoma in the shoulder of a pediatric patient.

We report the computed tomography (CT) and magnetic resonance imaging (MRI) features of a 10-year-old boy with low-grade fibromyxoid sarcoma (LGFMS) in the shoulder and correlate them with the clinicopathological features. LGFMS, a rare soft tissue sarcoma with bland histological features and paradoxically aggressive behavior, tends to occur in superficial regions and in children more than previously recognized. To date, few imaging studies have been reported, particularly in pediatric patients. In this case, precontrast CT showed a low- to isodensity mass and punctate calcification. On contrast-enhanced CT, heterogeneous enhancement was seen. MRI findings correlated well with the pathological features of the tumor. The myxoid area showed high signal intensity on T2-weighted MR images and heterogeneous enhancement after administration of contrast material; the hypercellular area demonstrated lower signal intensity on T2-weighted MR images and slight enhancement.

Child↗
PubMed2006

Leiomyosarcoma of the renal vein: arterial encasement on contrast-enhanced dynamic computed tomography.

We report a case of leiomyosarcoma of the renal vein, which is a rare tumor with no more than 30 cases found in the published English language literature. This case demonstrates encasement of the renal artery by the tumor mass, a previously unreported manifestation. The present study could be useful in considering this rare tumor in the differential diagnosis of renal hilar tumors.

Aged↗
PubMed2006

Expression of CD27 on peripheral CD4+ T-lymphocytes correlates with the development of severe acute graft-versus-host disease after allogeneic bone marrow transplantation.

Allogeneic immune responses during hematopoietic reconstitution play central roles in beneficial and adverse effects after allogeneic bone marrow transplantation (allo-BMT). Appropriate regulation of the immune responses might improve the outcome of allo-BMT. However, a useful marker for monitoring allogeneic immune responses remains to be established. We enrolled 22 consecutive patients who underwent myeloablative allo-BMT between March 2002 and March 2006 and examined the relationship between CD27 expression on peripheral blood T-lymphocytes, a possible marker for naive/effector phenotypes, and clinical events, especially acute graft-versus-host disease (aGVHD). In 8 patients with aGVHD of grades II to IV, the CD27+/CD27- ratios of CD4+ (but not CD8+) T-lymphocytes were significantly higher after allo-BMT, even at day 21, than the ratios in patients with aGVHD of grade 0 or I and remained high after day 21. In contrast, the ratios were low after day 21 following allo-BMT in 14 patients with aGVHD of grade 0 or I. Moreover, the clinical analysis suggested a relationship between the ratio and aGVHD grade. Thus, we showed that the CD27+/CD27- ratio in CD4+ T-lymphocytes may have value in predicting the development of severe aGVHD and may correlate with clinical symptoms of aGVHD.

Acute Disease↗
PubMed2005

Sclerosing perineurioma: Tumor of the hand with a short T2.

We present two cases of sclerosing perineurioma, a rare soft tissue tumor, in the palm and the ring finger respectively, presenting as a small, painless and subcutaneous mass. This tumor has a predilection for the digits and palms of young, predominantly male adults. In the present cases the tumors showed very low signal intensity on T2-weighted magnetic resonance (MR) images. Histologically they contained abundant collagen and hyalinized stroma, which would account for areas of low signal intensity on T2-weighted MR images. Immunohistochemically, the tumor cells were positive for vimentin, epithelial membrane antigen and human erythrocyte glucose transporter 1 and negative for S-100 protein. To the best of our knowledge, the appearance of sclerosing perineurioma on MR imaging has not been previously reported in the English-language literature. Sclerosing perineurioma should be considered in the differential diagnosis of hand tumors when the tumor shows low signal intensity on T2-weighted MR images.

Adolescent↗
PubMed2005

Direct determination of several elements in MIBK extract by high-power nitrogen-oxygen mixed gas microwave-induced plasma optical emission spectrometry.

A nitrogen-oxygen mixed gas microwave-induced plasma with an Okamoto cavity was employed as an atomization and excitation source for emission spectrometric analysis of organic solvent samples. Nitrogen-oxygen mixed gas produces very a stable microwave-induced plasma that is highly robust to the loading of 4-methyl-2-pentanone (MIBK), possibly because the organic solvent is completely combusted in the oxygen-containing plasma. After extracting test solutions containing Al, Co, Cr(III), Cu, Fe(III), Mo(VI), Ni, Pb with MIBK, both the aqueous phase and the organic phase were aspirated into the microwave-induced plasma, yielding linear calibration curves for both the species in the aqueous phase (Al, Co, Cr, Ni, and Pb) and those in the organic phase (Fe and Mo). These results indicate that Fe and Mo can be extracted with MIBK, which is explained by the partition coefficients of these elements in MIBK.

Journal Article↗
PubMed2005

Extraskeletal osteosarcoma: extensive tumor thrombus on fused PET-CT images.

A 30-year-old woman developed extraskeletal osteosarcoma in the right buttock and thigh. Radiographs and unenhanced computed tomography (CT) showed a large, multilobulated mass accompanied by mineralized matrix. Contrast-enhanced CT and magnetic resonance (MR) images showed extensive tumor thrombus in the right internal- and external iliac veins. Co-registered positron emission tomography (PET) and CT images showed abnormal F-18 2-fluoro-2-deoxy-D-glucose (FDG) uptake in the tumor thrombus. PET study in our patient provided information concerning disease extent and viability of tumor thrombus.

Adult↗
PubMed2005

Hepatic hemangioma presenting atypical radiologic findings: a case report.

A 69-year-old woman was referred to our hospital due to a liver tumor that was incidentally noted on ultrasound (US). US revealed a pedunculated mass of 5 cm in diameter, with a heterogeneous echo pattern. On arterial phase dynamic contrast-enhanced computed tomography (CT), a tiny enhancing dot in the upper aspect of the mass was seen; whereas, the main portion of the lesion appeared as hypoattenuating. The tumor was of low intensity on T1-weighted magnetic resonance (MR) images, and showed slightly heterogeneous high intensity on T2-weighted MR images. The most characteristic feature of the tumor was its exophytic appearance. On post-gadolinium hepatic arterial dominant-phase MR images, the tumor showed nodular enhancement centrally, with progressive spread of enhancement on later images. Angiography showed dilatation of the right posterior inferior branch of the hepatic artery and C-shaped opacification. Since we could not rule out malignancy for these nonspecific radiologic findings, a partial resection of the liver was carried out, resulting in a pathological diagnosis of hepatic hemangioma. This hemangioma had marked hyalinization and fibrosis, causing a heterogeneous appearance on MR images. The tumor presented an exophytic appearance, which caused some diagnostic confusion.

Aged↗
PubMed2005

Pulmonary involvement of malignant melanoma: thin-section CT findings with pathologic correlation.

OBJECTIVES: The purpose of this study was to characterize the thin-section computed tomography (CT) findings of primary and secondary pulmonary malignant melanoma and to correlate them with the histopathologic features. MATERIALS AND METHODS: Patients were identified from a pathologic registration system database through a query for patients with diagnosed primary or secondary pulmonary melanoma who had undergone surgical resection. A total of 19 pulmonary malignant melanomas, including one primary and 18 secondary involvements, from 10 patients were enrolled into this study. The patients consisted of 3 men and 6 women, with a mean age of 55 years (range, 28 to 71 years). Thin-section CT findings evaluated by consensus between two radiologists were compared with the histopathologic specimens. RESULTS: Tumor size ranged from 4 to 62 mm (mean, 19 mm) on thin-section CT images. Four characteristic patterns including solitary or multiple solid nodule, endobronchial lesion, cavitary nodule, and nodule with ground-glass attenuation were disclosed by correlation between thin-section CT and pathologic findings. The most common thin-section CT finding was a solid nodule with a well-defined, smooth margin (n=14). Endobronchial lesions were seen in one primary and one secondary involvement (n=2). Less common CT findings were cavitary nodule (n=1) and nodule with ground-glass attenuation (n=1). CONCLUSION: Primary and secondary pulmonary malignant melanomas show various patterns of involvement on thin-section CT.

Adult↗