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Biomedical subjects

Y Tezuka

Publications and source records attributed to Y Tezuka.

At least 109 records · Page 6Linked to original sources
PubMed1995

Expression of thrombomodulin in esophageal squamous cell carcinoma and its relationship to lymph node metastasis.

Thrombomodulin (TM) is thrombin receptor that was identified originally on the endothelium and acts as a natural anticoagulant. However, we reported previously that TM was also expressed in the squamous epithelium mainly at the intercellular bridges. In this study, we examined TM expression in the primary lesions of 106 patients with esophageal squamous cell carcinomas and in the lymph node metastatic lesions of 59 patients using immunohistochemical methods. The carcinoma tissues expressed TM mainly at the cell-cell boundaries and in the cytoplasm. When TM expression was compared between the primary and metastatic lesions in the 59 patients who had lymph node metastasis, 41 (69%) showed decreased TM expression, 18 (31%) showed no change, and none (0%) showed an increase in the metastatic lesions. Wilcoxon's signed-rank test indicated that tumor cells that were positive for TM expression were significantly rarer in the metastatic lesions than in the primary tumors (P < 0.0001). This result indicates that the decrease in TM expression is associated with metastasis of the carcinoma cells. This phenomenon is very similar to that of E-cadherin, although the structures of both molecules are quite different. The reduction of TM expression seems to play an important role in the metastatic process of esophageal cancer.

Adult↗
PubMed1995

Lymph node metastasis and the recurrence of esophageal carcinoma with emphasis on lymphadenectomy in the neck and superior mediastinum.

A series of 335 patients with squamous cell carcinoma of the thoracic esophagus undergoing resection and reconstruction via a right thoracotomy and laparotomy with cervical anastomosis between 1973 and 1990, were reviewed. Prior to 1982, the removal of lymph nodes was limited to the nodes in the mediastinum below the tracheal bifurcation and upper abdomen (142 patients). Nodal metastases were found in 89 of these patients at operation. The upper abdominal nodes were the most frequent sites of metastasis (47.2%). None of the 38 patients with positive nodes sampled from the neck and superior mediastinum survived for more than 45 months. In the 50 patients with recurrences, 30 were in the neck and/or superior mediastinum. During or after 1983, the superior mediastinal nodes, particularly the bilateral recurrent nerve nodal chains, were routinely removed (193 patients). Nodal metastasis was proven in 131 of the 193 patients, in whom 87 (45.1%) had metastasis in the neck and superior mediastinum. Eleven of these 87 patients survived for 45 months or more. In the 61 patients with recurrences, 20 were in the neck and/or superior mediastinum. These data suggest that recurrent nerve nodal chains should be removed to improve survival in patients with esophageal carcinoma.

Aged↗
PubMed1995

Studies on metabolites of mycoparasitic fungi. IV. Minor peptaibols of Trichoderma koningii.

Three minor peptaibols, trichokonins (TKs)-Ia, Ib, and IX, were obtained from the culture broth of Trichoderma koningii Oudemans. Primary structures of these peptaibols were elucidated by ion-spray ionization mass spectrometry (ISI-MS) including the collision-induced dissociation (CID) technique together with two-dimensional nuclear Overhauser enhancement spectroscopy (NOESY).

Alamethicin↗
PubMed1995

Studies on metabolites of mycoparasitic fungi. II. Metabolites of Trichoderma koningii.

Four peptaibols, named trichokonins (TKs) V, VI, VII, and VIII, were isolated from the culture broth of Trichoderma koningii Oudemans. Primary structures of these peptaibols were elucidated by electrospray ionization mass spectrometry (ESI-MS), FAB-MS, and collision-induced dissociation (CID) techniques along with nuclear Overhauser enhancement spectroscopy (NOESY).

Alamethicin↗
PubMed1994

Trichokonin VI, a new Ca2+ channel agonist in bullfrog cardiac myocytes.

The effects of trichokonin VI (= gliodeliquescin A), a peptaibol isolated from the culture broth of Trichoderma koningii Oudemans, on L-type Ca2+ channel currents in single bullfrog atrial cells were investigated. Our results showed that trichokonin VI is a new potent agonist of L-type Ca2+ channels in cardiac membranes.

Alamethicin↗
PubMed1994

Identification of matrix metalloproteinase 9 in rabbit osteoclasts.

Osteoclasts are multinucleate giant cells that play key roles in bone resorption. To identify genes predominantly expressed in osteoclasts, we screened a cDNA library of osteoclasts with cDNA probes of osteoclasts and alveolar macrophages. Clones specifically hybridizing to the osteoclast probe were isolated and sequenced. The nucleotide sequence of one such clone, F17, was found to share significant similarity with the sequences of human and mouse matrix metalloproteinase 9 (MMP-9) cDNA. By isolation and sequencing of the full-length cDNA, F17 was revealed to encode the rabbit counterpart of MMP-9. By Northern blotting, messenger RNA for MMP-9 was found to be highly and predominantly expressed in isolated osteoclasts when compared with its level in alveolar macrophages and other tissues. By gelatin zymography, gelatinase activity was detected in conditioned medium of isolated osteoclasts, suggesting that MMP-9 is secreted by isolated osteoclasts. Expression of MMP-9 was also observed in in vivo osteoclasts in metacarpal bones of newborn rabbits by in situ hybridization. These facts suggest that MMP-9 is one of the major proteases produced by osteoclasts and possibly plays a role in osteoclastic bone resorption.

Amino Acid Sequence↗
PubMed1994

Molecular cloning of a possible cysteine proteinase predominantly expressed in osteoclasts.

Osteoclasts are multinucleate giant cells playing key roles in bone resorption. These cells solubilize mineralized bone matrix by means of acid and protease action; however, the precise mechanism of this process is not well known. Recently, we succeeded in the isolation of pure osteoclasts from rabbit bones and constructed a cDNA library. Using a differential screening procedure, two genes expressed predominantly in osteoclasts compared with spleen cells were isolated (Tezuka, K., Sato, T., Kamioka, H., Nijweide, P. J., Tanaka, K., Matsuo, T., Ohta, M., Kurihara, N., Hakeda, Y., and Kumegawa, M. (1992) Biochem. Biophys. Res. Commun. 186, 911-917). One of them, OC-2, was found to encode a possible cysteine proteinase structurally related to cathepsins L and S. By in situ hybridization, OC-2 was confirmed to be expressed in osteoclasts in vivo. By Northern blot analysis, OC-2 was highly and preferentially expressed in osteoclasts compared with other tissues such as kidney, liver, spleen, and lung. The predominant expression of OC-2 in osteoclasts may suggest that OC-2 encodes a protein, possibly a cysteine proteinase, that plays an important role in osteoclastic bone resorption.

Amino Acid Sequence↗
PubMed1994

Nuclear Overhauser effect spectroscopy (NOESY) detection of the specific interaction between substituents in cellulose and amylose triacetates.

Nuclear Overhauser effect spectroscopy measurements on cellulose triacetate and on amylose triacetate with a mixing time of 500 ms, on the order of T1 of acetyl protons, were performed to detect the specific through-space interaction between acetyl groups arising from their helix structures in solution. For cellulose triacetate, cross peaks were detected in CDCl3 between acetyl proton signals at 3 and 6 positions on an anhydroglucose unit. In DMSO-d6, on the other hand, correlation peaks were observed not only between the 3 and 6 positions but also the 2 and 6 positions. For amylose triacetate, cross peaks were detected in CDCl3 between the acetyl proton signals at the 2 and 6 positions. The through-space interaction of acetyl groups in cellulose triacetate and in amylose triacetate in solution was then interpreted based on their three-dimensional structures in solid state determined by x-ray crystallography.

Amylose↗
PubMed1994

Expression of desmoglein I in squamous cell carcinoma of the esophagus.

Desmoglein I (DGI) is major component of the desmosomal membrane core that plays an important role in epithelial cell adhesion. The aim of this study was to explore the correlation between the expression of DGI and the clinicopathological findings of esophageal cancer. DGI expression was immunohistochemically examined using an anti-DGI monoclonal antibody in 139 patients with squamous cell carcinoma of the esophagus. Normal squamous epithelial cells strongly expressed DGI at their cell-cell boundaries. According to the intensity and pattern of DGI expression, the cancerous tissues were divided into three groups: DGI (++), DGI (+), and DGI (-). Of the 139 tumors, 35 (25%) were DGI (++), 65 (47%) were DGI (+), and 39 (28%) were DGI (-). A good inverse correlation between DGI expression and tumor invasion, lymph node metastasis, lymphatic invasion, and vessel invasion was observed. These results indicate that DGI expression may be a significant factor for invasion, metastasis, and prognosis of human esophageal cancer.

Adult↗
PubMed1993

Dauricoside, a new glycosidal alkaloid having an inhibitory activity against blood-platelet aggregation.

Dauricoside (1), a new glycosidal alkaloid, was isolated from the rhizomes of Menispermum dauricum DC. along with dauricine (2), daurisoline (3), dauriporphine (4), menisporphine (5), and 6-O-demethylmenisporphine (6), and its structure was determined by means of spectroscopic methods. Compounds 1, 2, and 3 inhibited blood-platelet aggregation induced by adenosine 5'-diphosphate (ADP).

Alkaloids↗
PubMed1992

Phenoxazinone synthesis by human hemoglobin.

We found that 2-amino-5-methylphenol was converted to the dihydrophenoxazinone with a reddish brown color by purified human hemoglobin, lysates of human erythrocytes, and human erythrocytes. The reddish brown compound was identified as 2-amino-4,4 alpha-dihydro-4 alpha,7-dimethyl-3H-phenoxazin-3-one by the measurement of NMR spectra, IR spectra, EI mass spectra, and absorption spectra. The changes in this phenoxazinone were studied under various conditions after mixing 2-amino-5-methylphenol with purified oxy- or methemoglobin, or with human erythrocytes. The production of 2-amino-4,4 alpha-dihydro-4 alpha,7-dimethyl-3H-phenoxazine-3-one from 2-amino-5-methylphenol was found to be tightly coupled with the oxidation of ferrous hemoglobin and reduction of ferric hemoglobin under aerobic conditions. By studying the production rates of the dihydrophenoxazinone and the oxido-reduction rates of ferrous and ferric hemoglobins during the reactions of ferrous or ferric hemoglobin with 2-amino-5-methylphenol under aerobic and anaerobic conditions, the reaction mechanism was extensively proposed.

Carbon Isotopes↗
PubMed1992

Scoparic acid A, a beta-glucuronidase inhibitor from Scoparia dulcis.

The 70% EtOH extract of Scoparia dulcis showed inhibitory activity against beta-glucuronidase from bovine liver. Bioassay-directed fractionation of the active extract led to the isolation of three labdane-type diterpene acids, scoparic acid A [1] [6-benzoyl-12-hydroxy-labda-8(17), 13-dien-18-oic acid], scoparic acid B [2] [6-benzoyl-14,15-dinor-13-oxo-8(17)-labden-18-oic acid], and scoparic acid C [3] [6-benzoyl-15-nor-14-oxo-8(17)-labden-18-oic acid], the structures of which were established by spectral means, including X-ray analysis. Scoparic acid A was found to be a potent beta-glucuronidase inhibitor.

Acetylation↗
PubMed1992

Isolation of novel lignans, heteroclitins F and G, from the stems of Kadsura heteroclita, and anti-lipid peroxidative actions of heteroclitins A-G and related compounds in the in vitro rat liver homogenate system.

From the stems of Kadsura heteroclita, two new lignans named heteroclitins F and G were isolated and their structures were determined by various spectroscopic means including an X-ray diffraction method. Dibenzocyclooctadiene type lignans and related compounds isolated from the stems of K. heteroclita, potently inhibited the lipid peroxidation in the rat liver homogenate stimulated by Fe(2+)-ascorbic acid, CCl4-reduced form of nicotinamide adenine dinucleotide phosphate (NADPH) and adenosine 5'-diphosphate-NADPH.

Animals↗
PubMed1992

Constituents of a fern, Davallia mariesii Moore. II. Identification and 1H- and 13C-nuclear magnetic resonance spectra of procyanidin B-5, epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin, and epicatechin-(4 beta----6)-epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin.

Procyanidin B-5 (1), epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin (2), and epicatechin-(4 beta----6)-epicatechin-(4 beta----8)-epicatechin-(4 beta----6)-epicatechin (3), which showed an inhibitory effect toward protein kinase C, were isolated from the rhizomes of Davallia mariesii Moore. Detailed analyses of their 1H- and 13C-nuclear magnetic resonance spectra were carried out by the use of two-dimensional nuclear magnetic resonance techniques.

Biflavonoids↗