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Biomedical subjects

H Kumamoto

Publications and source records attributed to H Kumamoto.

At least 37 records · Page 2Linked to original sources
PubMed2001

Genetic analysis of DNA microsatellite loci in salivary gland tumours: comparison with immunohistochemical detection of hMSH2 and p53 proteins.

To investigate genetic alterations in salivary gland tumours, microsatellite instability at eight representative loci and loss of heterozygosity (LOH) on chromosome 17 were analysed by polymerase chain reaction amplification. The results were compared with immunohistochemical expression of the hMSH2 and p53 proteins. Microsatellite instability and expression loss of hMSH2 protein were not recognized in the salivary gland tumours, suggesting a low frequency of abnormalities of the mismatch repair system. LOH associated with the p53 gene was detected in approximately one-half of pleomorphic adenomas and salivary carcinomas, which often showed strong p53 immunoreactivity. These features suggest that the p53 gene plays an important role in malignant transformation of salivary gland tumours. The genetic characteristics of pleomorphic adenomas might reflect a low-grade potential for malignant progression.

Adenoma, Pleomorphic↗
PubMed2001

Stereo- and regioselective radical cyclization of 6-(bromomethyl)dimethylsilyl-1',2'-unsaturated uracil nucleosides: synthesis of 1'-alpha-hydroxymethyl nucleosides.

Mode of radicalcyclization (5-exovs. 6-endo) was investigated by using 6-(bromomethyl)dimethylsilyl derivatives of 1',2'-unsaturated uridine with an aim to develop a new stereoselective method for the introduction of an alpha-hydroxymethyl group at the anomeric position. Although the 2'-unsubstituted derivative underwent only 6-endo-cyclization, substrates bearing 2'-CO2Me or 2'-OBz group gave exclusively 5-exo-cyclized products with a high stereoselectivity.

Bromine Compounds↗
PubMed2001

Immunohistochemical detection of amelogenin and cytokeratin 19 in epithelial odontogenic tumors.

OBJECTIVE: Epithelial odontogenic tumors exhibit considerable histological variation and are classified into several benign and malignant entities. Expression of amelogenin and cytokeratin 19 (CK19), that are potentially useful polypeptides for identification of odontogenic epithelial components, was evaluated in various types of epithelial odontogenic tumors. MATERIALS AND METHODS: Specimens of 33 ameloblastomas, three calcifying epithelial odontogenic tumors (CEOTs), two clear cell odontogenic tumors (CCOTs) and five malignant ameloblastomas were examined by immunohistochemistry using anti-amelogenin and anti-CK19 antibodies. RESULTS: Immunohistochemical reactivity for amelogenin was detected in many peripheral columnar or cuboidal cells and some central polyhedral cells in ameloblastomas, and histological variants showed various degrees of amelogenin expression. Expression of CK19 was diffusely present in neoplastic cells in ameloblastomas, and decreased expression was found in keratinizing cells of acanthomatous variants and some neoplastic cells of desmoplastic variants. In CEOTs, immunohistochemical reactivity for amelogenin was detected in neoplastic cells and intercellular amyloid-like materials, whereas CK19 was expressed in neoplastic cells. CCOTs showed positive reactivity for amelogenin and CK19 in neoplastic cells. Malignant ameloblastomas exhibited various degrees of amelogenin expression with constant CK19 expression in neoplastic cells. CONCLUSION: Diverse types of epithelial odontogenic tumors express amelogenin and CK19, suggesting that these tumors have ameloblastic differentiation or odontogenic epithelial properties.

Ameloblastoma↗
PubMed2001

Sarpogrelate diminishes changes in energy stores and ultrastructure of the ischemic-reperfused rat heart.

Although the involvement of serotonin in exacerbating vascular abnormalities in ischemic heart disease has been established, its role in mediating changes in cardiac function due to ischemia reperfusion (IR) is poorly understood. The aim of this study was to investigate the effect of a serotonin blocker, sarpogrelate (5-HT2A antagonist), in preventing cardiac injury due to IR. Isolated rat hearts were subjected to 30 min of global ischemia followed by 1 h of reperfusion. Sarpogrelate (50 nM-0.9 microM) was infused 10 min before ischemia as well as during the reperfusion period. The IR-induced changes in left ventricular developed pressure, left ventricular end diastolic pressure, rate of pressure development, and rate of pressure decay were attenuated (P < 0.05) with sarpogrelate treatment. Sarpogrelate also decreased the ultrastructural damage and improved the high energy phosphate level in the IR hearts (P < 0.05). This study provides evidence for the attenuation of IR-induced cardiac injury by 5-HT2A receptor blockade and supports the view that serotonin may contribute to the deleterious effects of IR in the heart.

Animals↗
PubMed2000

Clear cell odontogenic tumor in the mandible: report of a case with duct-like appearances and dentinoid induction.

A case of clear-cell odontogenic tumor with unusual histological features is presented. A 61-year-old Japanese man was admitted because of swelling of the left premolar-molar region of the mandible. Radiological examination revealed a multilocular radiolucency with irregular margins. Histological examination of the resected specimen showed infiltrative proliferation of both clear and eosinophilic cells into the adjacent soft tissue without encapsulation, suggesting the malignant potential of the tumor. The tumor cells sporadically formed cystic lesions. In addition, several tumor cell nests showed duct-like characteristics, and many eosinophilic dentin-like structures were attached to the tumor cell nests, suggesting the potential for epithelial-mesenchymal induction. Histochemically, the clear tumor cells possessed cytoplasmic glycogen granules. Both clear and eosinophilic tumor cells showed positive immunoreactivities for cytokeratin 19, epithelial membrane antigen and filaggrin, indicating an odontogenic epithelial origin.

Dentin↗
PubMed2000

Suppressive effect of saprogrelate hydrochloride on Raynaud's phenomenon and respiratory failure in patients with systemic sclerosis.

OBJECTIVE: In seven patients with systemic sclerosis (SS), we evaluated the clinical effectiveness of oral administration of saprogrelate hydrochloride (SH: 300 mg/day) for 2 months on Raynaud's phenomenon (RP) and respiratory failure estimated by Hugh-Jones classification. METHODOLOGY: We evaluated laboratory data (arterial blood gas (pH, PaO2 and PaCO2), pulmonary function tests (%VC, FEV1/FVC and %DL(CO)), mean pulmonary arterial pressure (mPAP), white blood cell count, C-reactive protein and the plasma levels of fibrinopeptide A (FPA), beta-thrombogloblin (beta-TG), platelet factor 4 (PF4) and thrombomodulin (TM)) before and after SH administration. RESULTS: The frequency and duration of RP, as well as the coldness, numbness and pain of RP were significantly decreased after SH administration (P < 0.05, P < 0.01 and P < 0.001). Respiratory failure estimated by Hugh-Jones classification was also significantly decreased after SH administration (P < 0.05), and the %DL(CO) was significantly increased (P < 0.01). The mPAP decreased significantly after SH administration (P < 0.05). Plasma FPA, beta-TG and PF4 significantly decreased after administration (P < 0.05 and P < 0.01). CONCLUSIONS: SH therapy could prevent RP and respiratory failure in patients with SS.

Adult↗
PubMed2000

Lithiation study on D4T.

Upon treatment with LTMP, 5'-O-protected D4T undergoes deprotonation of the vinylic proton (H-3' or H-2'): when 5'-O-silyl derivative was used, the 3'-C-silylated product was formed as a result of C3'-lithiation and subsequent O-->C silyl migration, while deprotonation at the 2'-position led to the formation of an allene derivative. A stannyl version of this reaction was also examined to develop a method for C3'-functionalization of D4T.

Lithium↗
PubMed2000

Alveolar soft-part sarcoma of the cheek: report of a case with a review of the literature.

An alveolar soft-part sarcoma (ASPS) occurring in the cheek is described, with a review of the literature. The subject was a 25-year-old woman who presented with a large swelling in the left cheek. The lesion, initially diagnosed as a benign tumor on radiographic and computed tomographic examinations, was surgically excised. Histopathological examination of the mass revealed a nest-like or organoid cellular arrangement as confirmed by three-dimensional computer graphic reconstruction. The cytoplasm of the large polygonal tumor cells contained abundant diastase-resistant, PAS-positive inclusions, ultrastructurally confirmed to be crystalloid materials. The tumor cells were immunoreactive for anti-myoglobin, sarcomeric actin, and neuron-specific enolase antibodies, suggesting a myogenic origin.

Adult↗
PubMed1999

Expression of 5-HT2A and 5-HT1B receptor mRNA in blood vessels.

Expression of two subtypes of 5-hydroxytryptamine (5-HT) receptors, 5-HT1B and 5-HT2A, was investigated in normal rat arteries (abdominal aorta) and veins (inferior vena cava) by the quantitative reverse transcription-polymerase chain reaction (RT-PCR). The arterial 5-HT2A receptor mRNA level in artery was 25-fold (p < 0.01) higher than the venous level, and the arterial 5-HT1B receptor mRNA level was at least 7000-fold (p < 0.005) higher the venous level.

Animals↗
PubMed1999

Expression of E-cadherin and alpha-catenin in epithelial odontogenic tumors: an immunohistochemical study.

To clarify the possible role of cell adhesion in epithelial odontogenic tumors, expression of E-cadherin and alpha-catenin was examined by an immunohistochemical method. These molecules showed pericellular distribution in epithelial cells of the tooth germ and its derived tumors. In ameloblastomas, E-cadherin and alpha-catenin were expressed strongly in central polyhedral cells and slightly in peripheral columnar cells. These features resembled those of epithelial components in the tooth germ tissues, retaining cytodifferentiation of odontogenic epithelium. Expression of the molecules in the variants of ameloblastomas showed loss in the keratinizing areas and reduction in the granular cell clusters, suggesting terminal differentiation of the tumor cells. Calcifying epithelial odontogenic tumors and a clear cell odontogenic tumor preserved E-cadherin and alpha-catenin expression without a specific feature for histogenesis or cytodifferentiation. One case of two malignant ameloblastomas showed prominent reduction in expression of E-cadherin and alpha-catenin.

Ameloblastoma↗
PubMed1999

Clear cell variant of calcifying epithelial odontogenic tumor (CEOT) in the maxilla: report of a case with immunohistochemical and ultrastructural investigations.

A rare case of clear cell variant of calcifying epithelial odontogenic tumor is presented with immunohistochemical and ultrastructural investigations. A 14-year-old Japanese girl was admitted with a complaint of swelling in the right posterior maxilla. Radiological examination showed a well-circumscribed radiolucent lesion located close to the impacted third molar. After only a partial tumor excision, the tumor recurred 13 years later. It appeared radiologically as an irregular radiodensity, and a subtotal maxillectomy was performed. Histological examination showed sheets and/or strands composed almost entirely of clear vacuolated epithelial cells in a stroma containing intercellular amyloid-like material and calcification. Histochemical and ultrastructural analysis detected cytoplasmic glycogen granules in the clear cells, and positive immunoreactivities for cytokeratins 8, 13 and 19; filaggrin and anti-ameloblastoma antibodies suggested an odontogenic epithelial origin.

Adolescent↗
PubMed1999

Immunohistochemical analysis of bcl-2 family proteins in benign and malignant ameloblastomas.

To study the possible roles of bcl-2 family proteins in oncogenesis and cytodifferentiation of odontogenic epithelium, the expression of bcl-2, bcl-x and bax proteins was examined immunohistochemically in tooth germs and various types of ameloblastoma. In ameloblastomas, bcl-2 and bcl-x proteins were expressed intensely in peripheral columnar cells and weakly in central polyhedral cells, while bax protein reactivity was low. In variants of ameloblastoma, no expression of these proteins was found in the keratinizing areas or granular cell clusters. Basal cell ameloblastomas showed intense reactivity for bcl-2 and bcl-x proteins, but slight or no reactivity for bax protein. These results indicate that in ameloblastomas the bcl-2 family proteins might function primarily as anti-apoptotic factors, reflecting proliferative activity. Malignant ameloblastomas showed decreased reactivity for bcl-2 protein and increased levels of bax protein as compared with benign ones.

Ameloblastoma↗
PubMed1999

Beneficial effect of myocardial angiogenesis on cardiac remodeling process by amlodipine and MCI-154.

The present study examined the effect of long-term treatment with amlodipine and MCI-154 (a Ca2+ sensitizer) on progressive cardiac dysfunction and microvasculature in the dilated cardiomyopathic (DCM) hamster heart. After treatment of DCM hamsters (Bio 53.58) with amlodipine or MCI-154 for 15 wk from the age of 5 wk, amlodipine and MCI-154 were found to cause an increase in left ventricular percent fractional shortening and decreases in left ventricular diastolic dimension and isovolumic relaxation time in echocardiograms (P < 0.01). A hemodynamic study showed that the diastolic time constant decreased in the amlodipine-treatment group (P < 0.05). In a morphometric study employing a double-staining method that discriminated arteriolar and venular capillaries, amlodipine and MCI-154 caused increases in total capillary density (P < 0.05) and the proportion of venular capillaries (P < 0.05). Moreover, Northern blot analysis showed that the expression of mRNA for vascular endothelial growth factor was significantly increased by amlodipine and MCI-154. They preserve coronary microvasculature in the DCM hamster and might induce angiogenesis of small vessels, thereby contributing to preservation of cardiac systolic and diastolic function.

Amlodipine↗
PubMed1999

Inhibition of serotonin-induced vascular smooth muscle cell proliferation by sarpogrelate.

Antiproliferative behavior of sarpogrelate (Anplag, MCI-9042, (+/-)-1-[2-[2-(3-methoxyphenyl)ethyl]phenoxy]-3-(dimethylamino)-2-pro pyl hydrogen succinate hydrochloride), a serotonin 2A (5-HT2A) receptor antagonist, was established using radioactive incorporation of [(3)H]thymidine, [(3)H]uridine, and [(3)H]phenylalanine in cultured rat aortic smooth muscle cells in response to a 5-HT-induced cytokine trigger. Fluorescence-activated cell sorting was used to confirm these observations. 5-HT-induced DNA, RNA, and protein synthesis were inhibited maximally at a concentration of 1 microM sarpogrelate. Although other cytokines such as platelet-derived growth factor and endothelin also induced DNA, RNA, and protein synthesis in rat aortic smooth muscle cells, cell proliferation was not influenced by sarpogrelate, even at large pharmacological concentrations (10 microM). Sarpogrelate's antiproliferative actions were found to be more potent than ketanserin. These data indicate that sarpogrelate operates as a specific inhibitor of 5-HT-mediated cell proliferation and is a good candidate for preventing serotonin-induced neointimal hyperplasia.

Animals↗
PubMed1998

Multiple organ failure associated with extensive metastatic calcification in a patient with an intermediate state of human T lymphotropic virus type I (HTLV-I) infection: report of an autopsy case.

A patient with an intermediate state of human T lymphotropic virus type I (HTLV-I) infection and in whom autopsy showed multiple organ failure (MOF) associated with extensive metastatic calcification in systemic organs is described. A 56-year-old man presented with signs and symptoms of advanced cardiac insufficiency, respiratory disturbance and renal failure. Serologically, the anti-human T lymphotropic virus type I (HTLV-I) antibody titer and the levels of both calcium and parathyroid hormone-related peptide (PTHrP) were distinctly elevated. These data suggested a diagnosis of adult T cell lymphoma/leukemia (ATLL). However, examination of a peripheral blood sample revealed only a few atypical lymphoid cells (3%) associated with mild leukocytosis (white blood cell count, 13.7 x 10(3)/mm3). Lymph node swelling was systemic but mild, with some nodes up to 10 mm in diameter. The patient died of MOF. Adult T cell leukemia/lymphoma was unable to be diagnosed definitively because of the short duration of laboratory abnormalities and because of the discrepancy between the laboratory data and the magnitude of lymphoproliferation in both the lymph nodes and peripheral blood. At autopsy, the most conspicuous finding was extensive metastatic calcification in the multiple organs, including the heart, lungs, kidneys, tongue, liver, pancreas, spleen and systemic arterial walls. Very small numbers of medium-sized atypical lymphoid cells admixed with small reactive lymphocytes were identified in multiple organs, with no evidence of massive infiltration. Molecular analyses could not detect monoclonal integration of HTLV-I provirus DNA or monoclonality of T cell lineage cells. Parathyroid hormone-related peptide was demonstrated in the cytoplasm of the atypical lymphoid cells on immunohistochemical examination. The bone trabeculae generally showed distinct evidence of resorption associated with marked proliferation of osteoclasts. These findings suggested that the hypercalcemia in the present case was categorized as humoral hypercalcemia of malignancy rather than local osteolytic hypercalcemia.

Autopsy↗
PubMed1998

Clear cell odontogenic tumor in the mandible: report of a case with an immunohistochemical study of epithelial cell markers.

A rare case of clear cell odontogenic tumor is presented with an immunohistochemical study using epithelial cell markers. A 35-year-old Japanese man was admitted with a complaint of painless swelling in the anterior region of his mandible. Radiological examination showed a relatively well-defined multilocular radiolucency with root resorption of the adjacent teeth. Despite a subtotal mandibulectomy, the tumor recurred three times. Histologically, the tumor was composed of proliferating clear cells and infiltrated through the cancellous bone. Histochemical and ultrastructural analyses detected cytoplasmic glycogen granules in the clear cells. They showed immunoreactivities for cytokeratin 8, 13 and 19, filaggrin and anti-ameloblastoma antibodies, suggesting an odontogenic epithelial origin.

Adenocarcinoma, Clear Cell↗