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T Manabe

Publications and source records attributed to T Manabe.

At least 127 records · Page 7Linked to original sources
PubMed1999

Energy filtering transmission electron microscopy using the new JEM-2010FEF.

The new JEM-2010FEF electron microscope provides useful techniques based on energy filtering as an omega-type energy filter is integrated into a thermal field-emission 200 kV transmission electron microscope. For example, the zero-loss imaging improves the contrast of high resolution lattice images as well as images of precipitates or lattice defects in alloys. The acquisition time for elemental mapping with core-loss electrons is one order in magnitude shorter than with energy-dispersive X-ray spectroscopy. The removal of inelastically scattered electrons enables us to observe weak lines in convergent-beam electron diffraction patterns from a thicker specimen with a probe size 1-2 nm in diameter. A combination of the field emission gun and sensitive recording media such as an imaging plate and a slow-scan CCD camera makes the energy filtering more powerful.

Journal Article↗
PubMed1999

Solid-pseudopapillary carcinoma of the pancreas.

A case of solid-pseudopapillary carcinoma (SPC) of the pancreas in a 34-year-old Japanese woman is presented. An abdominal ultrasonography revealed a mass, which measured 10 cm in diameter, in the body and tail of the pancreas. The tumor was resected and it was originally diagnosed as a non-functioning islet cell tumor. One year and five months later, the patient was re-admitted to hospital, and liver metastasis was confirmed by ultrasonography. The patient died 6 days after the second transcatheter arterial embolization (TAE) required for the metastasis. The autopsy showed small foci of liver metastasis. A retrospective examination of the tumor suggested the diagnosis of SPC because of its characteristic solid and pseudopapillary structures, immunohistochemical findings, and liver metastasis. This case suggests that capsular invasion, specifically found at the surgical margin of the peritoneal side, may be an important pathological finding that is suggestive of malignant potential in solid-pseudopapillary tumor. If there is such a finding in a surgical specimen, an intensive follow up should be advised to the clinician.

Adult↗
PubMed1999

Cutaneous granulocytic sarcoma mimicking immunoblastic large cell lymphoma.

A peculiar case of cutaneous granulocytic sarcoma without leukemic manifestation (so-called aleukemic leukemia cutis) that developed in the skin of the back of a 69-year-old man is reported. A skin biopsy specimen showed atypical cells with a prominent nucleolus proliferating around dermal blood vessels and along adnexa without epidermotropism. Atypical cells similar to those of the skin had infiltrated diffusely into the interfollicular area of an inguinal lymph node. Flow cytometric and immunohistochemical studies with a panel of monoclonal antibodies revealed neoplastic cells that had a biphasic phenotype of myeloid and T cell precursors. They expressed CD13, CD15, CD33, lysozyme, CD3epsilon, CD4, CD7 and terminal deoxynucleotidyl transferase (TdT). Gene analysis showed no rearrangement of the immunoglobulin heavy chain or T cell receptor beta and gamma genes. Ultrastructurally, the tumor cells exhibited a few intracytoplasmic electron-dense granules and well-developed rough endoplasmic reticulum with an occasional whorling arrangement. The initial diagnosis was immunoblastic large cell lymphoma, and the patient was treated with six courses of ProMACE-CytaBOM. In spite of the high-grade cytological characteristics of this tumor, the patient has been free of disease for 5 years.

Aged↗
PubMed1999

Immunohistochemical assessment of human bone marrow macrophages in hematologic disorders.

Changes in bone marrow macrophages may be associated with abnormal hematopoiesis in various hematologic disorders. We immunohistochemically evaluated the density of macrophages in bone marrow trephine biopsies. In reactive erythroid hyperplasia (hemolytic anemia and megaloblastic anemia), the macrophages slightly increased in density, extending their cytoplasmic processes between hematopoietic cells. In erythroid hypoplasia (pure red cell aplasia), they became rounded and frequently had hemosiderin granules. There was no significant difference in the macrophage density in the hematopoietic area between erythroid hyperplasia and hypoplasia. The macrophages increased in density in myeloproliferative disorders (polycythemia vera, chronic myelogenous leukemia and primary thrombocythemia). In myelofibrosis, some macrophages became extremely elongated along the line of the fibroblastic cells. In contrast, in conditions in which myelopoietic activity is considerably impaired (aplastic anemia, acute leukemia and multiple myeloma), they significantly decreased in density. These results suggest that the morphologic change in bone marrow macrophages is associated with erythropoietic activity and that there is a correlation between macrophage density and myelopoietic activity.

Antibodies, Monoclonal↗
PubMed1999

Platelet-activating factor receptor is not required for long-term potentiation in the hippocampal CA1 region.

From pharmacological studies, platelet-activating factor (PAF) has been proposed as a retrograde messenger for long-term potentiation (LTP) in the hippocampal CA1 region. We re-examined a possible contribution of PAF to LTP with a more specific approach using mice deficient in the PAF receptor. The PAF receptor-deficient mice exhibited normal LTP and showed no obvious abnormality in excitatory synaptic transmission. We also performed pharmacological experiments on the wild-type mice. Two structurally different antagonists of PAF receptors had no effects on LTP. Furthermore, the application of PAF itself caused no detectable changes in excitatory synaptic transmission. Thus, we conclude that the PAF receptor is not required for LTP in the CA1 region. Introduction

Animals↗
PubMed1999

Calcium-dependent mechanisms involved in presynaptic long-term depression at the hippocampal mossy fibre-CA3 synapse.

Long-term potentiation (LTP) and long-term depression (LTD) are induced presynaptically at the hippocampal mossy fibre-CA3 synapse. Activation of presynaptic metabotropic glutamate receptors (mGluRs) is necessary, but not sufficient for the LTD induction. Using mouse hippocampal slices, we attempted to identify additional presynaptic factors involved in the induction of mossy fibre LTD. Suppression of a rise in the presynaptic intracellular Ca2+ concentration ([Ca2+]i) with a membrane-permeable Ca2+ chelator, 1, 2-bis(2-aminophenoxy)ethane-N,N,N',N'-tetraacetic acid tetraacetoxymethyl ester (BAPTA-AM), reduced the magnitude of LTD, whereas an increase in Ca2+ influx induced LTD, suggesting that an elevation of presynaptic [Ca2+]i is crucial for the LTD induction. A broad-spectrum protein kinase inhibitor, H-7, blocked LTD without affecting a presynaptic inhibition induced by an mGluR agonist. Furthermore, LTD was reduced by an inhibitor of calmodulin or Ca2+/calmodulin-dependent protein kinases. Thus, we conclude that mossy fibre LTD requires an increase in presynaptic [Ca2+]i and subsequent activation of Ca2+/calmodulin-dependent protein kinases. Because mossy fibre LTP may also require a rise in presynaptic [Ca2+]i, bidirectional long-term plasticity at the mossy fibre synapse is likely to be regulated by presynaptic Ca2+-dependent processes.

1-(5-Isoquinolinesulfonyl)-2-Methylpiperazine↗
PubMed1999

Doc2alpha is an activity-dependent modulator of excitatory synaptic transmission.

Doc2alpha is a synaptic vesicle-associated Ca2 + -binding protein. To study the role of Doc2alpha in synaptic transmission and modulation, we generated homozygous null Doc2alpha mutant mice. In the CA1 region of hippocampal slices in the mutant mice, excitatory synaptic responses evoked with prolonged 5 Hz stimulation showed a significantly larger frequency facilitation followed by a steeper depression than those in wild-type mice, whereas there was no difference in synaptic transmission at lower frequencies or in paired-pulse facilitation. These results suggest that Doc2alpha regulates synaptic transmission when high Ca2 + concentrations in the presynaptic terminal are sustained. Furthermore, the mutant mice showed impairment in long-term potentiation and passive avoidance task. Thus, Doc2alpha may regulate transmitter release during repetitive synaptic activation, thereby contributing to memory formation.

6-Cyano-7-nitroquinoxaline-2,3-dione↗
PubMed1999

p53 mutations in tumor and non-tumor tissues of thorotrast recipients: a model for cellular selection during radiation carcinogenesis in the liver.

Concerns over cancer development from exposure to environmental sources of densely ionizing, high linear energy transfer (LET) radiation, such as alpha-particles from radon, is a current public health issue. The study of tumors attributable to high LET irradiation would greatly augment our insights into the biological mechanisms of carcinogenesis. Chronic low-dose-rate internal exposure to alpha-radiation from thorium dioxide deposits following intravascular administration of the radiographic contrast agent Thorotrast is known to markedly increase the risk of cancer development, especially that of hepatic angiosarcomas and cholangiocarcinomas. Although the mechanism is hypothesized to be via cellular damage, DNA being a major target, wrought by the high LET alpha-particles, the specific genes and the actual sequence of events involved in the process of transforming a normal cell into a malignant one are largely unknown. To shed some light on the molecular mechanisms of cancer development during a lifetime exposure to alpha-radiation, we analyzed the most commonly affected tumor suppressor gene in humans, p53, in 20 Thorotrast recipients who developed cancer, mostly of hepatic bile duct and blood vessel origin. Of the 20 cases, 19 were found to harbor p53 point mutations. Moreover, the accompanying non-tumor tissues from these patients also had p53 mutations, albeit at lower frequency. The distribution pattern of the point mutations was significantly different between the non-tumor and tumor tissues, with most mutations in malignant tissues located in the highly conserved domains of the p53 gene. Our results support the idea that p53 mutations are important in the genesis of Thorotrast-induced tumors but that these point mutations are a secondary outcome of genomic instability induced by the irradiation. Additionally, non-tumor cells harboring p53 mutations may gain some survival advantage in situ but mutations in the domains responsible for the formation of structural elements critical in binding DNA may be necessary for a cell to reach full malignancy.

Aged↗
PubMed1999

Basement membrane material in ovarian clear cell carcinoma: correlation with growth pattern and nuclear grade.

Stromal hyalinization in ovarian clear cell carcinomas has been suggested to be caused by deposition of basement membrane (BM) material, but the biological and diagnostic significance of this finding remains unknown. The distribution of BM material in 17 primary ovarian clear cell carcinomas was examined semiquantitatively using hematoxylin and eosin-stained sections and immunohistochemistry with antibodies to laminin and type IV collagen. For comparison, other surface epithelial tumors, including 8 serous tumors of low malignant potential, 10 serous adenocarcinomas, 6 mucinous tumors of low malignant potential, 5 mucinous adenocarcinomas, 6 endometrioid carcinomas, 4 Brenner tumors, 1 transitional cell carcinoma, and 3 undifferentiated carcinomas, were examined. Stromal hyalinization was found in all 17 clear cell carcinomas and was immunoreactive for type IV collagen and laminin. Other types of surface epithelial tumor lacked these findings. In clear cell carcinoma, areas showing a papillary pattern tended to show abundant deposition regardless of nuclear grade, whereas in solid, tubular, or cystic areas, the deposition was more prominent in areas showing high-nuclear-grade features (grade 2 and 3) than in areas with low-nuclear-grade features (grade 1). Dense deposition of BM material recognized as stromal hyalinization on hematoxylin and eosin-stained sections in primary ovarian clear cell carcinoma is a characteristic feature that is not seen in other ovarian surface epithelial tumors. This matrix production correlates with high-nuclear-grade features and papillary growth pattern.

Adenocarcinoma, Clear Cell↗
PubMed1999

Basaloid type adenoid cystic carcinoma of the breast.

We report a case of adenoid cystic carcinoma (ACC) of the breast with a prominent basaloid feature. The patient was a 62-year-old Japanese woman with a right breast mass, measuring 1.5 cm in diameter. Histologically, the tumor was composed of basal cell-like tumor cells, and it was originally diagnosed as invasive ductal carcinoma. The presence of PAS-positive basement membrane material around the tumor cell nests may be a diagnostic clue to ACC. The prognosis of ACC of the breast is considered to be favorable. However, basaloid type ACC may represent a poor prognosis, since our case revealed an aggressive behavior in spite of its small size.

Breast Neoplasms↗
PubMed1999

Bamboo-joint-like appearance of the stomach: a histopathological study.

A bamboo joint-like (BJL) appearance is an endoscopic finding characterized by swollen longitudinal folds transversed by erosive fissures or linear furrows, and it seems to be associated with Crohn's disease (CD). We performed gastroduodenoscopy in 1781 patients, and found BJL lesions in 15 (65.2%) of 23 CD patients and 20 (1.1%) of 1758 non-CD patients. Histological examination of the biopsy specimens showed sharp, fissure-like erosion or mucosal cleft in 7 (50%) out of 14 CD patients and one (20%) out of 5 non-CD patients. All cases with fissure-like erosion or, mucosal cleft revealed lymphoid aggregates, eosinophilic infiltration and edema in the superficial portion of the surrounding lamina propria. Epithelioid granuloma was seen at the base of the fissure-like erosion in two cases with CD. Our results indicated that fissure-like erosion or mucosal cleft in gastric biopsy specimens reflects the BJL appearance, and that such findings may provide a diagnostic clue to CD.

Adult↗
PubMed1999

Intraosseous epithelioid malignant peripheral nerve sheath tumor of the phalanx. Case report.

We report the first case of intraosseous epithelioid malignant peripheral nerve sheath tumor (MPNST) occurring in the phalanx. The patient was a 50-year-old Japanese man with an intramedullary lytic lesion of the proximal phalanx. Microscopically, the tumor was composed of epithelioid cells or polygonal cells, forming large cell nests with central necrosis. Most tumor cells were diffusely and strongly immunopositive for S-100 protein and vimentin, and negative for cytokeratin, epithelial membrane antigen, carcinoembryonic antigen, alpha-smooth muscle actin, and HMB-45. Laminin-positive material was discontinuously demonstrated between the individual tumor cells. Electron microscopy showed prominent external lamina. Our case indicated that laminin is useful for differentiating epithelioid MPNST from metastatic carcinoma and malignant melanoma.

Bone Neoplasms↗
PubMed1999

Clinicopathological features of serrated adenoma of the colorectum: comparison with traditional adenoma.

AIM: Serrated adenoma is a recently described category of colorectal adenoma. The aim of this study was to determine whether serrated adenomas have clinicopathological findings distinct from "traditional" adenoma. METHODS: Colonoscopy records for 1995-1998 were reviewed, and all traditional adenomas and serrated adenomas identified. Tumour site and endoscopic configuration were compared between the two types of adenoma. In polypectomised lesions, size and grade of dysplasia were compared between the two groups. RESULTS: There were 3305 traditional adenomas and 43 serrated adenomas. Serrated adenomas were more often found in the rectosigmoid colon than the traditional adenomas (67.5% v 41.2%, p = 0.0008). Polypectomy was more often done for serrated adenomas (27 of 43 lesions, 62.8%) than for traditional adenomas (626 of 3305 lesions, 18.9%, p < 0.0001). Size (mean (SD) maximum dimension, 12 (6) mm v 13 (3) mm) and incidence of high grade dysplasia (14.8% v 13.6%) in endoscopically removed specimens were not different between the two types. CONCLUSIONS: The therapeutic judgement applied to the management of traditional adenoma seems to be appropriate for serrated adenoma.

Adenoma↗
PubMed1999

Noncardiogenic pulmonary edema as the chief manifestation of a pheochromocytoma: a case report of MEN 2A with pedigree analysis of the RET proto-oncogene.

Pheochromocytomas are rare neoplasias of the adrenal medulla which generally present with paroxysmal or sustained hypertension. Cardiogenic pulmonary edema is a common feature of these tumors, but few cases have been described with noncardiogenic pulmonary edema. We report a pheochromocytoma with the principle manifestation of noncardiogenic pulmonary edema and characterize a genetic lesion associated with the disorder. A 30-year-old man was admitted with abdominal pain and breathlessness. x-Ray examination of the chest revealed a massive, diffuse infiltration of the left lung without cardiomegaly. No paroxysmal blood pressure fluctuations or heart failure were evident during the entire course, and the infiltrate and dyspnea resolved in three days without inotropic or diuretic agents. Serum norepinephrine and epinephrine levels were elevated twenty and fifty times above normal, respectively. The patient was ultimately diagnosed with multiple endocrine neoplasia type 2A (MEN 2A). Mutations in the RET proto-oncogene have been described recently in patients with MEN 2A. Mutation analysis of selected RET exonic sequences identified a germline mutation at codon 634 in exon 11 of the RET proto-oncogene. The mutation introduces a transition encoding a non-conservative substitution from TGC (Cys) to CGC (Arg) and creates a novel restriction site recognized by HhaI. We further screened for this mutation among four of the proband's relatives by HhaI restriction analysis. One asymptomatic family member was identified who subsequently elected prophylactic total thyroid removal. Histological examination of this specimen confirmed the presence of medullary thyroid carcinoma.

Adrenal Gland Neoplasms↗
PubMed1999

[A case of hepatocellular carcinoma with tumor thrombus in the right atrium successfully treated by arterial administration of lipiodol-SMANCS].

In February, 1996, a 73-year-old male with liver dysfunction was admitted to our hospital for further examination and treatment of liver tumor. The liver tumor was revealed by imaging examination, which was mainly in the S4-S8 of liver with a thrombus growing from the right anterior branch to the right branch of the portal vein, and from the right hepatic vein to the inferior vena cava and right atrium. The serum AFP and PIVKA-II levels were elevated to 3.610 ng/ml and 54 AU/ml, respectively. The patient was diagnosed as having hepatocellular carcinoma, and was treated by arterial administration of anticancer drugs (epirubicin hydrochloride, mitomycin C and carboplatin) and TAE. Though the main tumor (S4-S8 of liver) was reduced by TAE, the portal and atrial tumor thrombus did not respond. One month after TAE (20 May, 1996), the first arterial administration of Lipiodol-SMANCS was given, followed by 4 successive procedures with an interval of about 1.5 months (total dose 15 mg), resulting in remarkable tumor thrombus shrinkage and reduction of AFP levels to 80 ng/ml. This case shows that arterial administration of SMANCS may be one of the effective treatments for hepatocellular carcinoma, even with tumor thrombus of hepatic vein, IVC and right atrium.

Aged↗
PubMed1999

[Prognostic factors for oral tongue carcinoma treated with intra-oral cone electron beam irradiation].

Twenty-five patients with squamous cell carcinoma of the oral tongue were treated with intra-oral cone electron beam irradiation (IOC) during the period from 1985 to 1995. We analyzed the prognostic factors for local control and complications. IOC was applied for T1 (16 cases) and T2 (9 cases) tumors. Hypofractionation was used for IOC (20, 10, or 8 Gy/fr, 1f/wk). The total dose delivered ranged from 40 Gy to 78 Gy. Radiation dose homogenization was done through calculation of the normalized total dose (NTD) for alpha/beta = 10 (tumor) and alpha/beta = 3 (late normal tissue). The two-year local control rates for T1 and T2 were 80.4% and 77.8%, respectively. The two-year local control rates for patients whose overall treatment time (OTT) was < or = 28 days (n = 16) was 100% vs. 41.7% for patients whose OTT was > 28 days (n = 9) (p = 0.002). Multivariate analysis was applied to identify possible prognostic factors for local control. OTT (p = 0.02) was the only variable that significantly influenced local control. The incidence of radiation ulcer was 33.3% (7/21). Significant indicators of ulceration were fraction size (>> 10 Gy) and NTD (alpha/beta = 3) (>> 130 Gy) (p < 0.05). These results indicate that prolonged OTT was the major reason for the failure of IOC radiotherapy to control local disease and that the relatively high rate of ulceration was due to large fraction size and high NTD (alpha/beta = 3).

Adult↗