Search PubMed⌕ Search

Biomedical subjects

T Tsuda

Publications and source records attributed to T Tsuda.

At least 415 records · Page 23Linked to original sources
PubMed1990

Stimulation of platelet-derived growth factor-induced DNA synthesis by angiotensin II in rabbit vascular smooth muscle cells.

In cultured rabbit vascular smooth muscle cells (VSMCs), angiotensin II by itself had little mitogenic effect even in the presence of cell-free plasma-derived serum (PDS), but markedly stimulated the platelet-derived growth factor (PDGF)-induced DNA synthesis in the presence of PDS. The maximal extent of DNA synthesis induced by PDGF plus angiotensin II was about twice that induced by PDGF alone. The stimulatory effect of angiotensin II was dose-dependent with the maximal response seen at 1 microM and was inhibited by the specific angiotensin II receptor antagonist, [Sar1, Ile8]angiotensin II. In VSMCs, both PDGF and angiotensin II induced expression of the c-fos gene in dose-dependent manners. In contrast to the synergistic effect of angiotensin II and PDGF on DNA synthesis, they induced expression of the c-fos gene in an additive manner. These results suggest that angiotensin II may act as a growth regulator for VSMCs in addition to acting as a vasoconstrictor.

Angiotensin II↗
PubMed1990

Two distinct light regulated G-proteins in octopus photoreceptors.

Two distinct light-regulated G-proteins were found in octopus photoreceptors. Gip, a 41 kDa protein from washed microvilli, was ADP ribosylated by pertussis toxin in the presence of GDP in the dark. Light and GTP analogues were inhibitory as with transducin (Gt; G-protein in vertebrate photoreceptors). G34, a 34 kDa protein from fresh octopus retina, was ADP ribosylated by both cholera and pertussis toxin in the dark. Light inhibited labeling of the 34 kDa protein by both toxins. Unlike Gip, G34 is soluble and is very labile to heat, freezing and thawing. Prolonged incubation of octopus retina with cholera toxin and labeled NAD produced an additional radioactive band at 46 kDa. Labeling of the 46 kDa protein, Gsp, was greatly enhanced by GTP analogues, but inhibited by a GDP analogue as with Gs in hormone-sensitive adenylate cyclase. In contrast to Gip and G34, labeling of the 46 kDa protein (Gsp) was not influenced by light. The two distinct light-regulated G-proteins, Gip and G34, found in octopus photoreceptors might be involved in either phototransduction or photoadaptation. The function of Gsp is not known.

Adenosine Diphosphate Ribose↗
PubMed1990

Molecular genetic survey of five Japanese families with high-molecular-weight kininogen deficiency.

Analyses of the kininogen (KGN) molecule and KGN gene status in five Japanese families with high-molecular-weight (HMW) KGN deficiency were performed by the immunoblotting method with monoclonal antibodies to HMW-KGN, and by the Southern blotting method with the cDNA for human low-molecular-weight prekininogen. No molecular abnormality of KGN was detected in the DNA from four patients with total KGN deficiency or one patient with isolated HMW-KGN deficiency. In the former, the KGN gene appeared to be grossly normal at the level of the whole genome on Southern blotting. In isolated HMW-KGN deficiency, a partial deletion in intron 7 was found by restriction analyses of EcoRI, BamHI, HindIII, Sca I, and Bgl II fragments. This partial deletion is assumed to be related to an abnormality of the alternative RNA splicing events for HMW-prekininogen mRNA.

Antibodies, Monoclonal↗
PubMed1990

[The role of gallium-67 citrate scintigraphy in gastro-intestinal malignant lymphoma].

To evaluate the clinical usefulness of gallium-67 scintigraphy in the detection of the gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, gallium-67 scintigraphy was reviewed on 24 cases (25 lesions; stomach in 20, ileum in 2, and terminal ileum and/or cecum in 3). Twenty-three out of the 25 lesions (92.0%) were detected by gallium-67 scintigraphy, while barium study could detect all of the 25 lesions. The sizes of the gallium-67 negative 2 lesions were the smallest of all (2.5 and 3.0 cm). The tumor size was considered to the most important factor in the detection by gallium-67 scintigraphy, while the histological classification and the location of the tumor were not related to its detectability. Findings in follow-up gallium-67 scintigraphy after therapy on 10 cases were correlated well with the therapeutic effects. These data suggest that gallium-67 scintigraphy is useful for the detection of GI involvement of NHL and for the assessment of therapeutic effects.

Adult↗
PubMed1990

EGF and TGF-alpha, the ligands of hyperproduced EGFR in human esophageal carcinoma cells, act as autocrine growth factors.

In order to ascertain autocrine growth factors in esophageal carcinomas, we analysed expression of mRNAs and proteins for epidermal growth factor (EGF), transforming growth factor-alpha (TGF-alpha) and epidermal growth factor receptor (EGFR) in 6 esophageal carcinoma cell lines. Gene alterations were also examined. All of the esophageal carcinoma cell lines expressed mRNA for EGFR and TGF-alpha genes. Interestingly, EGF mRNA of about 5.0 kb was also detected in TE-1, TE-2, and TE-8 cells. Production of protein was also confirmed by binding assay and ELISA on 3 of the 6 cell lines. The cells had a relatively high number of EGFRs and produced TGF-alpha and EGF protein at the same time. Furthermore, anti-EGF (KEM-10) and anti-TGF-alpha (WA-3) monoclonal antibodies (MAbs) inhibited spontaneous uptake of tritiated thymidine (3H-TdR) by TE-1 cells which expressed EGF, TGF-alpha and EGFR mRNA and protein. These results strongly suggest that EGF and/or TGF-alpha produced by carcinoma cells function as autocrine growth factors for human esophageal carcinomas.

Adenocarcinoma↗
PubMed1990

Angiotensin II stimulates phosphorylation of nuclear lamins via a protein kinase C-dependent mechanism in cultured vascular smooth muscle cells.

Angiotensin II (ang II) induces c-fos gene expression in part via a protein kinase C-dependent mechanism in cultured vascular smooth muscle cells (VSMC). However, little is known about the mechanisms by which protein kinase C regulates nuclear functions. We examined the ability of ang II to phosphorylate nuclear lamina proteins in VSMC and the possibility that protein kinase C is involved in these putative phosphorylation events. Ang II stimulated the phosphorylation of Triton X-100- and high salt-insoluble nuclear envelope proteins with molecular weights of 70,000, 67,000, and 60,000. These proteins were identified as lamins A, B, and C, respectively, based on their mobilities on two-dimensional gel electrophoresis and interaction with antibodies to lamins as detected by immunoblot analyses. After a 2-min delay, phosphorylation levels of lamins increased, peaked at 20-30 min, and were sustained for at least 60 min after ang II stimulation. The threshold, half-maximal, and maximal concentrations of ang II which induced phosphorylation of lamins were 0.1, 0.5-1, and 100 nM, respectively. Phorbol 12-myristate 13-acetate also induced these reactions, whereas ionomycin did not. Down-regulation of protein kinase C by prolonged treatment with phorbol 12,13-dibutyrate attenuated ang II-induced phosphorylation of lamins. In vitro phosphorylation of nuclear envelope proteins by protein kinase C revealed that lamins served as substrates for this enzyme. These results indicate that ang II induces phosphorylation of lamins in cultured VSMC and suggest that protein kinase C is either directly or indirectly involved in these reactions. The results raise the possibility that phosphorylation of nuclear proteins is one of the important steps by which the protein kinase C signaling pathway regulates agonist-induced nuclear events.

Angiotensin II↗
PubMed1990

Degradation peptides of secretin after storage in acid and neutral aqueous solutions.

During the storage of secretin in acid and neutral aqueous solutions, five degradation peptides (A1, A2, A3, A4, A5) and one degradation peptide (N1) were produced, respectively. They were isolated in pure form by HPLC, and the intramolecular structures were studied by a combination of amino acid analysis, enzymatic digestions, HPLC, and Fab-mass spectroscopy. Although the degradation peptides are composed of the same amino acids as secretin after acid hydrolysis (except A1 and A4 which are cleavage products S16-27 and S4-27, respectively), reversed-phase HPLC analysis of their digestive fragments with trypsin and alpha-chymotrypsin are different from those of secretin. By Fab-mass spectroscopy, the m/z values for the S1-6 fragments obtained from secretin, A2, and A3 were 663, 663, and 645, respectively. When S1-6 from A2 was treated with aminopeptidase M, a fragment obtained was identical with the synthetic beta-aspartyl3 S3-6, as determined by HPLC. The A2 and N1 peptides are completely the same based on various chemical analyses. The A3 peptide can also be rapidly degraded to secretin and beta-aspartyl3 secretin. Consequently, A1 and A4 are concluded to be the cleavage peptides of secretin, S16-27 and S4-27, respectively, A2 and N1 are concluded to be beta-aspartyl3 secretin, and A3 is concluded to be aspartoyl3 secretin.

Amino Acid Sequence↗
PubMed1990

Mechanism and kinetics of secretion degradation in aqueous solutions.

In order to clarify the mechanism of secretin degradation in aqueous solutions, the formation of degradation products from secretin, aspartoyl3 secretin and beta-aspartyl3 secretin was investigated; the stabilities of these three peptides were investigated as well. Aspartoyl3 secretion and beta-aspartyl3 secretin, degradation peptides produced during the storage of secretin in aqueous solutions, were isolated by preparative reversed-phase HPLC (RP-HPLC). The amounts of secretin and its two degradation peptides resulting from storage of secretin in various buffer solutions (pH 2.3 to 10.0, mu = 0.5 M, 60 degrees C) were determined by analytical RP-HPLC. Secretin and the isolated degradation peptides were stored separately in various aqueous buffer solutions resulting in the degradation of each peptide. A mixture of secretin and its degradation or cleavage peptides was formed in each solution. The observed degradation rates for each peptide approximately followed first-order kinetics. The pH-rate profiles for conversion of secretin and beta-aspartyl3 secretin were similar, while that for aspartoyl3 secretin was different from these two. Aspartoyl3 secretin was more stable than the others at pH 2.3 to 4.0, but it was easily degraded between pH 5.0 and 10.0. Investigation of aspartoyl3 secretin degradation showed that its degradation was related to the pH value of the solution, and that hydroxide ion catalyzes the ring opening of the aspartoyl peptide. Secretin was most stable in pH 7.0 buffer solution and more stable in acidic solutions than in alkaline solutions. Secretion was mainly degraded through the following pathways: cleavage peptides reversible secretin in equilibrium aspartoyl peptide in equilibrium beta-aspartyl peptide vector cleavage peptides.

Buffers↗
PubMed1990

The role of gallium 67 imaging in non-Hodgkin's lymphoma of the gastrointestinal tract.

To evaluate the clinical usefulness of gallium 67 imaging in the detection of gastrointestinal (GI) non-Hodgkin's lymphoma (NHL) and in the assessment of the therapeutic effects, images were reviewed in 24 cases (25 lesions: stomach, 20; ileum, 2; and terminal ileum and or cecum, 3) and were compared using barium studies and, in 16 cases, computerized tomography (CT). In all, 23 (92.0%) of the 25 lesions were detected by 67Ga citrate imaging, the barium studies detected all 25, and CT detected 15 of 16 lesions (93.8%). The two lesions not identified by imaging and the one not found by CT were the smallest of all. In 2 (8.7%) of the 23 lesions positively identified by 67Ga-citrate imaging, both CT and imaging revealed the extent of the tumor more accurately than did the barium studies. In all but one of the patients, a close correlation existed between the imaging results and the therapeutic effects. These data suggest that 67Ga imaging is useful in conjunction with CT and barium studies for the detection of GI NHL and for the assessment of both the spatial extent of disease and the therapeutic effects, although a lack of 67Ga uptake after therapy does not always indicate a good therapeutic effect.

Barium Sulfate↗
PubMed1990

DNA ploidy pattern and amplification of ERBB and ERBB2 genes in human gastric carcinomas.

The DNA ploidy pattern and amplification of ERBB and ERBB2 genes were examined in paraffin-embedded tissue from gastric carcinomas using flow cytometry and a slot-blot hybridization technique. The incidence of aneuploidy in well differentiated adenocarcinomas (56%) was significantly higher (p less than 0.05) than that in poorly differentiated adenocarcinomas (21%). The DNA ploidy pattern was not remarkably different between the primary tumors and metastatic deposits in lymph nodes. Of the nine specimens having an aneuploid stem cell line in the primary tumor and/or in metastases, three showed ERBB2 gene amplification and one showed ERBB gene amplification. The incidence of epidermal growth factor (EGF) immunoreactivity in tumor cells showed no difference between diploid and aneuploid tumors. These findings indicate that aneuploidy is frequently associated with amplification of ERBB and ERBB2 genes.

DNA, Neoplasm↗
PubMed1990

Radioimmunoscintigraphy of human pancreatic carcinoma xenografts in nude mice with 131I-labeled monoclonal antibody.

Encouraged by reports of radioimmunoimaging of colorectal carcinomas and by examining an immunohistochemical report on resected pancreas cancer tissues, we studied the diagnostic potential of radioimmunoimaging with the radioiodinelabeled monoclonal antibody to the surface antigen of a pancreas cancer cell line. A monoclonal antibody (MoAb; HC-1) to a human pancreas cancer cell line (HGC25)5 was labeled with radioiodine and injected into athymic nude mice implanted with human pancreas cancer cells. Antibody HC-1 was cleared from the circulation and accumulated significantly in the implanted tumor sites.

Animals↗
PubMed1990

Pulmonary corpora amylacea contain surfactant apoprotein.

The case of a 53-year-old female with interstitial pneumonitis is described with special regard to biochemical characterization of pulmonary corpora amylacea which were found in the lung specimen obtained by bronchial biopsy from the patient. The main protein component in bronchoalveolar lavage (BAL) fluid of the patient was albumin, but proteins in the precipitate fraction of BAL fluid, where the corpora amylacea were recovered, predominantly consisted of 36 kD protein which was stained with the monoclonal antibody PE 10 to human pulmonary surfactant apoprotein by immunoblot. Histologically the pulmonary corpora amylacea were stained with eosin and PAS. The particles were stained immunohistochemically by immunoperoxidase reaction using PE 10, but not by antibodies to human albumin. The pulmonary surfactant apoprotein seems, therefore, to be not simply adsorbed in the particles, but to be contained in them. Thus, the surfactant apoprotein may, at least in this case, be involved in the formation of pulmonary corpora amylacea.

Apoproteins↗
PubMed1990

Transient abnormal myelopoiesis and diffuse hepatic necrosis in Down's syndrome with prominent bleeding diathesis.

The first case known to us with Down's syndrome with transient abnormal myelopoiesis and diffuse hepatic necrosis is reported. The infant had prominent bleeding diathesis and hepatosplenomegaly. She died on the 7th day because of intractable bleeding. The autopsy disclosed extramedullary hematopoiesis and extensive hepatic cell necrosis. Characteristic in our case was the outstanding bleeding diathesis due to coagulopathy.

Bone Marrow↗
PubMed1990

Interactions of hemopoietic cytokines on differentiation of HL-60 cells. Nerve growth factor is a basophilic lineage-specific co-factor.

Nerve growth factor (NGF) is a neurotropic polypeptide which has broad biological activity other than support of growth and survival of sympathetic, sensory and central neurons. NGF promotes rat mast cell hyperplasia in vivo and human granulopoiesis in vitro, selectively augmenting basophil/mast cell differentiation in the presence of T cells or conditioned medium derived from a human T cell line (Mo-CM), a source of granulocyte-macrophage colony-stimulating factor (GM-CSF). NGF also synergizes with GM-CSF to promote human basophil/mast cell differentiation in both methylcellulose and suspension cultures of myeloid progenitors. In the current studies, we examined the interactions of NGF and several cytokines considered to be involved in human basophil/mast cell and eosinophil growth and differentiation, including interleukin (IL)-3, IL-4, IL-5, GM-CSF and granulocyte colony-stimulating factor (G-CSF). NGF synergistically enhanced IL-5 induced dose-dependent increases in histamine content and basophilic cell differentiation of myeloid leukemic HL-60 cells, but was only additive to similar effects of IL-3. In contrast, IL-4 and G-CSF did not promote basophilic differentiation of HL-60 cells in the presence or absence of NGF. Various combinations of GM-CSF, G-CSF, IL-3, IL-4 and IL-5 could not reproduce the synergy observed between NGF and either IL-5 or GM-CSF. NGF appears to represent a class of lineage-specific co-factors, in this case being involved in GM-CSF- or IL-5-induced basophilic lineage differentiation, thus contributing to tissue inflammation or repair.

Animals↗
PubMed1990

Mass analysis of 1,2-diacylglycerol in cultured rabbit vascular smooth muscle cells. Comparison of stimulation by angiotensin II and endothelin.

We compared the effects of angiotensin II and endothelin on mass levels of 1,2-diacylglycerol, and endogenous activator of protein kinase C, in cultured rabbit vascular smooth muscle cells with the effects of these vasoconstrictors on contractile responses of rabbit aortic strips. At a high concentration (1 microM), both angiotensin II and endothelin induced a biphasic formation of 1,2-diacylglycerol with an early transient phase and a late sustained phase. At this high concentration, angiotensin II caused a transient contraction followed by a gradual relaxation, whereas endothelin caused a slowly developing and sustained contraction. At a low concentration (EC50 for the early phase of 1,2-diacylglycerol formation), angiotensin II also induced a biphasic formation of 1,2-diacylglycerol and caused a transient contraction, but endothelin induced a monophasic formation of 1,2-diacyglycerol with only an early peak. Despite a rapid decrease of 1,2-diacylglycerol, endothelin at this low concentration still caused a sustained contraction. At both the high and low concentrations, the 1,2-diacylglycerol level was sustained higher for angiotensin II, whereas the tension during the late tonic phase of contraction was greater for endothelin. These results suggest that the unique persistent nature of endothelin-induced contraction is not attributed simply to the stimulatory effect of this peptide on the 1,2-diacylglycerol/protein kinase C pathway.

Angiotensin II↗
PubMed1990

A serological comparison of 4 Japanese isolates of porcine enteroviruses with the international reference strains.

The reference strains of four serotypes (J6, J8, J9 and J10) of porcine enterovirus isolated in Japan were compared with the international reference strains of 11 serotypes (W1 to W11) by cross neutralization tests. No cross reactions were observed between the two groups, although there were minor one-way crosses between W10 and J10, W11 and J9, and W4 and J9. This leads to our conclusion that all 4 Japanese serotypes can be newly added to 11 international serotypes. J9 virus produced type 1 of CPE (CPE I), J6 and J8 did CPE II, and J10 did CPE III. J10 grew in Vero, HeLa cells, and the primate cells, but J6, J8 and J9 did not.

Animals↗
PubMed1990

Feasibility of intraoperative cytodiagnosis of lung cancer.

Of 354 thoracotomies, 114 cases involved intraoperative cytopathologic evaluation. The study included 86 men and 28 women, and 184 specimens were examined. Smears were taken from the lung lesion or lymph node and the chest wall or bronchial stump by imprint or needle aspiration. Intraoperative evaluations were compared with histologic findings. In 85 cases not diagnosed as malignant preoperatively, malignancy was confirmed in 97.6 percent of cases and histologic type in 71.8 percent. In the 28 cases diagnosed as malignant preoperatively, there was only one false-negative. The most important finding during thoracotomy is whether a lesion is malignant or not. The time required to obtain a pathologic diagnosis also is important. We are able to obtain the results of a cytologic diagnosis within 10 min. Cytologic diagnosis of malignancy during thoractomy may be a feasible and convenient method of diagnosis, especially where malignancy is suspected.

Adenocarcinoma↗