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Biomedical subjects

Y Ueda

Publications and source records attributed to Y Ueda.

At least 433 records · Page 24Linked to original sources
PubMed1997

FK-506 and cyclosporin A potentiate the IgE antibody production by contact sensitization with hapten in mice.

Five repeated topical applications of 2,4-dinitrofluorobenzene to the ears of BALB/c mice resulted in contact dermatitis on the ears as well as significant elevation in dinitrophenol-specific IgE antibody and total IgE in the serum. FK-506 and cyclosporin A inhibited the development of contact dermatitis in terms of skin thickness and histopathological changes of skin lesions. On the contrary, these two drugs potentiated dinitrophenol-specific and total IgE antibody production without affecting IgG and IgM levels in serum. The expression of interferon-gamma mRNA in reverse transcriptase-polymerase chain reaction in the ear was inhibited by FK-506 and cyclosporin A. The expression of interleukin-4 mRNA, germline C epsilon and productive C epsilon in the auricular lymph node was not affected by these two drugs. Contrary to the above in vivo findings, the immunosuppressors, FK-506 and cyclosporin A, inhibited the production of interferon-gamma and interleukin-2 by cultured Th1 cells (1E10.H2 cells) and of interleukin-4 and -5 by Th2 cells (D10.G4.1 cells) in vitro. These results indicated that FK-506 and cyclosporin A selectively inhibited the Th1 cell-mediated contact dermatitis and potentiated the Th2 cell-mediated IgE antibody production in vivo. This potentiation is probably due to the down-regulation of interferon-gamma production by Th1 cells after the treatment with these drugs. However, because FK-506 and cyclosporin A inhibited the production of cytokines by both Th1 and Th2 cells in vitro and these two immunosuppressors showed higher selectivity toward inhibiting Th1 cell-mediated reactions by limitations in vivo experiments.

Animals↗
PubMed1997

Helicobacter pylori infection in early gastric adenocarcinoma: relationship between histologic subtypes and ulcer-formation.

Early stage of gastric cancers were divided into two subtypes; differentiated and undifferentiated adenocarcinomas, histologically. We examined the involvement of Helicobacter pylori (Hp) infection in the development and progression of cancer, and presence or absence of peptic ulcer (UL+/UL-). From the results, these findings obtained as follows; 1) Hp positive rate of UL+ group was significantly higher than that of UL-group. 2) Neither of gross features nor depth of the tumor did not correlate with Hp positive rates. 3) Hp positive rate of undifferentiated type carcinoma was significantly higher than that of differentiated type, contrarily to our expectation. These findings suggested that Hp infection might relate with ulcer formation in the cancerous lesion. The hypothesis which is "gastritis-intestinal metaplasia-differentiated type carcinoma sequence" was not supported by present study. Hence, Hp infection was suggested as an important factor of the gastric cancer development and progression, not only in differentiated type but also in undifferentiated type.

Adenocarcinoma↗
PubMed1996

Role of salt bridge formation in antigen-antibody interaction. Entropic contribution to the complex between hen egg white lysozyme and its monoclonal antibody HyHEL10.

For elucidation of the role of salt bridge formation in the antigen-antibody complex, the interaction between hen egg white lysozyme (HEL) and its monoclonal antibody HyHEL10, the structure of which has been well characterized and forms one salt bridge (Lys97 of HEL and Asp32 of HyHEL10 heavy chain variable region (VH)), was investigated. Asp32 of VH was substituted with Ala, Asn, or Glu by site-directed mutagenesis, and the interaction between HEL and the mutant fragments of the variable region of light chain was investigated by inhibition of the enzymatic activity of HEL and isothermal titration calorimetry. Inhibition assay indicated that these mutations lowered the inhibition only slightly. Thermodynamic study indicated that the negative enthalpic change in the interaction between each of the mutant variable regions of light chain and HEL was significantly increased, although the association constant was slightly decreased, suggesting that these mutations increased the entropy change upon antigen-antibody binding. These results indicate that the role of salt bridge formation in the HyHEL10-HEL interaction is to lower the entropic loss due to binding. In the mutant proteins, the numbers of residues that were perturbed structurally on binding increased, suggesting that the salt bridge suppresses excess structural movement of the antibody upon binding.

Animals↗
PubMed1996

Moving from the orphanin FQ receptor to an opioid receptor using four point mutations.

It is unclear how receptor/ligand families that are evolutionarily closely related achieve functional separation. To address this question, we focus here on the newly discovered Orphanin FQ, a peptide homologous to the opioid peptide Dynorphin, and its receptor, the Orphanin FQ receptor, which is highly homologous to the opioid receptors. In spite of this high degree of homology in terms of both ligands and receptors, there is little direct cross-talk between the Orphanin FQ system and the endogenous opioid system. Thus, the opioid peptides show either relatively low affinity or no affinity toward the Orphanin FQ receptor; conversely, Orphanin FQ has no affinity toward any of the opioid receptors. We sought to investigate the molecular basis of such discrimination by attempting to reverse it and endowing the Orphanin FQ receptor with the ability to bind opioids. We report that by mutating as few as four amino acids, we can produce a receptor that recognizes pro-Dynorphin products with very high affinity and yet still binds Orphanin FQ as well as the wild-type receptor. This suggests that the Orphanin FQ receptor has developed features that specifically exclude the opioids and that these features are distinct from those required for the high affinity binding of its own endogenous ligand.

Analgesics↗
PubMed1996

Intertrabecular pattern of tumors metastatic to bone.

BACKGROUND: The prevalence of radiologically invisible metastatic tumors to bone is not known. To clarify this, the authors examined histologic sections, radiographs, bone scans, and magnetic resonance (MR) images of autopsied patients with bone metastases. METHODS: Complete slices of the vertebral column, including C3-S1, were obtained from 52 cadavers with metastatic tumors to the spine. Macroscopic and histologic features were compared with postmortem roentgenographs (52 patients), bone scans with 99mTc-labelled methylene diphosphonate (17 patients), and MR images (4 patients). Morphologic patterns were classified into intertrabecular, osteoblastic, osteolytic, mixed, small lesion, and compression fracture. RESULTS: Metastatic lesions were found in 734 of the 1194 vertebral bodies. The lesions were intertrabecular in 255 vertebrae, osteoblastic in 185, osteolytic in 114, mixed in 70, small lesion in 83, and compression fracture in 27. Postmortem radiographs demonstrated lesions in 367 (50%) of the 734 vertebrae, bone scans in 103 (34.7%) of the 297 vertebrae examined, and MR images in all 42 (100%) vertebral bodies imaged. Lesions showing an intertrabecular pattern were detected in only 7.1% of the radiographs and 4.5% of the bone scans. CONCLUSIONS: Radiographs and bone scans often fail to show metastatic lesions, especially those with an intertrabecular pattern. The intertrabecular pattern is a unique histologic form that is difficult to detect on radiographs and bone scans.

Adult↗
PubMed1996

Protein kinase C activates the MEK-ERK pathway in a manner independent of Ras and dependent on Raf.

Although the involvement of protein kinase C (PKC) in the activation of the mitogen-activated protein (MAP) kinase pathway has been implicated through experiments using 12-O-tetradecanoylphorbol-13-acetate (TPA), there has been no direct demonstration that PKC activates the MAP kinase pathway. A Raf-dependent intact cell assay system for monitoring the activation of MAPK/ERK kinase (MEK) and extracellular signal-related kinase (ERK) permitted us to evaluate the role of PKC isotypes in MAP kinase activation. Treatment of cells with TPA or epidermal growth factor resulted in the activation of MEK and ERK. The activation of the MAP kinase pathway triggered by epidermal growth factor was completely inhibited by dominant-negative Ras (RasN17), whereas the activation triggered by TPA was not, consistent with previous observations. The introduction of an activated point mutant of PKCdelta, but not PKCalpha or PKCepsilon, resulted in the activation of the MAP kinase pathway. The activation of MEK and ERK by an activated form of PKCdelta requires the presence of c-Raf and is independent of RasN17. These results demonstrate that activation of PKCdelta is sufficient for the activation of MEK and ERK and that the pathway operates in a manner dependent on c-Raf and independent of Ras.

3T3 Cells↗
PubMed1996

Mapping the receptor domains critical for the binding selectivity of delta-opioid receptor ligands.

While a good deal has been learned about determinants of high affinity ligand/receptor interactions in G-protein-coupled receptors, less is known about mechanisms of ligand selectivity. The opioid receptors offer an excellent opportunity to study the mechanisms whereby structurally very similar receptors discriminate between different but structurally highly related ligands. In the current study, we use a series of chimeric constructs between the delta-opioid receptor and either the mu- or the kappa-opioid receptors to investigate the structural basis of binding selectivity of multiple classes of delta-opioid receptor selective ligands. Our results demonstrate that a region containing the sixth transmembrane domain (TM6) and the third extracellular loop (EL3) in the delta-opioid receptor is absolutely critical for delta-opioid receptor selectivity. The introduction of this region into the kappa-opioid receptor is sufficient to impart a delta profile for delta-opioid receptor selective alkaloids such as naltrindole and naltriben. In order to locate the amino acid residues that may be involved in ligand selectivity in TM6 and EL3 of the delta-opioid receptor, several mutations were introduced into that region. These mutations showed differential effects on peptide and alkaloid ligands. In addition, none of the individual mutations alone could account for the changes exhibited by the chimeric receptors. We conclude that the selectivity of most delta-opioid ligands is achieved through their interaction with many different residues in the TM6/EL3 region. Our results also support a view that the extracellular domains of peptide receptors may provide the basis of a sorting mechanism for ligand selectivity.

Binding, Competitive↗
PubMed1996

Identification of pentosidine as a native structure for advanced glycation end products in beta-2-microglobulin-containing amyloid fibrils in patients with dialysis-related amyloidosis.

beta-2-Microglobulin (beta-2m) is a major constituent of amyloid fibrils in patients with dialysis-related amyloidosis (DRA). Recently, we found that the pigmented and fluorescent adducts formed nonenzymatically between sugar and protein, known as advanced glycation end products (AGEs), were present in beta-2m-containing amyloid fibrils, suggesting the possible involvement of AGE-modified beta-2m in bone and joint destruction in DRA. As an extension of our search for the native structure of AGEs in beta-2m of patients with DRA, the present study focused on pentosidine, a fluorescent cross-linked glycoxidation product. Determination by both HPLC assay and competitive ELISA demonstrated a significant amount of pentosidine in amyloid-fibril beta-2m from long-term hemodialysis patients with DRA, and the acidic isoform of beta-2m in the serum and urine of hemodialysis patients. A further immunohistochemical study revealed the positive immunostaining for pentosidine and immunoreactive AGEs and beta-2m in macrophage-infiltrated amyloid deposits of long-term hemodialysis patients with DRA. These findings implicate a potential link of glycoxidation products in long-lived beta-2m-containing amyloid fibrils to the pathogenesis of DRA.

Amyloid↗
PubMed1996

Intracoronary morphology of culprit lesions after reperfusion in acute myocardial infarction: serial angioscopic observations.

OBJECTIVE: This study sought to elucidate the morphologic and pathologic characteristics of culprit lesions in patients with acute myocardial infarction. BACKGROUND: The pathogenic mechanisms of acute myocardial infarction have been discussed on the basis of postmortem histologic examinations. Disruption of lipid-rich plaques is thought to render them thrombogenic. However, the details of coronary morphology have not been elucidated in survivors of myocardial infarction. The quality of angioscopic images has been greatly improved, and clear visualization of the intracoronary milieu can now be obtained. METHODS: Eleven patients with acute myocardial infarction and angiographic demonstration of the culprit lesion were entered into the study. Angioscopic observations were made immediately after reperfusion and at 1-month follow-up. RESULTS: Angioscopic observations were successfully performed in 10 patients immediately after reperfusion and in 10 at 33 +/- 26 (mean +/- SD) days of follow-up. Immediately after reperfusion, red thrombus, white thrombus, yellow plaques and intimal flaps were recognized in 30% (95% confidence interval [CI] 25.7 to 35.7), 100%, 100% and 50% (95% CI 45.0 to 55.0) of patients, respectively. At follow-up, these were recognized in 10% (95% CI 6.6 to 16.4), 60% (95% CI 54.6 to 64.7), 100% and 40% (95% CI 35.3 to 45.4) of patients, respectively. CONCLUSIONS: The thrombus in acute myocardial infarction was always recognized over the yellow plaques. The thrombus formed directly over the plaque was mainly white. Red thrombus might be formed after the blood flow was obstructed by the white thrombus. At approximately 1 month, yellow plaques remained in all patients, and > 50% still had adherent white thrombus.

Aged↗
PubMed1996

A stable phage-display system using a phagemid vector: phage display of hen egg-white lysozyme (HEL), Escherichia coli alkaline, phosphatase, and anti-HEL monoclonal antibody, HyHEL10.

A stable expression system for displaying the pIII fusion protein on the surface of a filamentous phage was constructed. A phagemid pIII display vector, pLUCK, was constructed by inserting the gene encoding the pIII fusion protein in the opposite direction to that of the lac promoter of pTZ18U. Using this phage display system, two enzymes, hen egg-white lysozyme (HEL) and E. coli alkaline phosphatase, and the single-chain Fv fragment of anti-HEL monoclonal antibody HyHEL10, could be stably and functionally displayed. Northern and primer extension analyses showed that a small amount of the sense mRNA encoding pIII-fused HEL was transcribed from the minor phage promoter located in the region encoding the C-terminus of pIII. Repressed expression of the pIII fusion protein can lead to the display of a wide range of proteins on filamentous phages without the need for strict expression conditions.

Alkaline Phosphatase↗
PubMed1996

Tumor-specific rearrangements of the immunoglobulin heavy-chain gene in B-cell non-Hodgkin's lymphoma detected by in situ hybridization.

We have recently described the potential use of fluorescence in situ hybridization (FISH) to detect tumor-specific rearrangements of the immunoglobulin heavy-chain (IgH) gene in interphase nuclei. Using yeast artificial chromosome (YAC) clone Y6 containing variable region (VH) gene and bacteriophage clones Ig gamma, we analyzed 70 patients with B-cell non-Hodgkin's lymphoma (NHL) and compared the results with those obtained by the conventional G-banding method. Tumor-specific rearrangements of the IgH gene equivalent to 14q32 translocations were defined as separate signals of VH and Ig gamma genes or those of Ig gamma genes and referred to split signals. Twenty-nine patients (41.4%) showed split signals. Among these, 13 did not show 14q32 translocations by G-banding: three with other chromosomal abnormalities, one with normal karyotype, and nine with no analyzable metaphases. The partner sites of 14q32 translocations were identified in 17 patients by FISH: t(3;14)(q27;q32) including a complex variant was observed in nine patients, t(14;18)(q32;q21) in four, t(8;14)(q24;q32) in three, t(14;19)(q32;q13) in one, and t(11;14)(q13;q32) in one. Six of nine patients with t(3;14) or its variant and one of three with t(8;14) were diagnosed as having respective translocations only by FISH. Translocation t(3;14) was found most commonly, and was correlated histologically with diffuse lymphoma with large-cell components. These results indicate that interphase FISH with IgH gene probes promises to be a rapid and reliable method for use in the diagnosis of B-cell NHL.

Adult↗
PubMed1996

Free radical scavenging activity of the Japanese herbal medicine toki-shakuyaku-san (TJ-23) and its effect on superoxide dismutase activity, lipid peroxides, glutamate, and monoamine metabolites in aged rat brain.

The free radical scavenging activity of the Japanese herbal medicine, Toki-Shakuyaku-San (TJ-23; TSUMURA & Co., Tokyo, Japan), was examined using electron spin resonance (ESR) spectrometry. TJ-23 scavenged 1,1-diphenyl-2-picrylhydrazyl radicals (DPPH), superoxide (O2-), and hydroxyl radicals (.OH) dose-dependently. It also diminished carbon centered radicals (.C) generated by oxidative stress and inhibited thiobarbituric acid-reactive substances (TBARS) formation in mouse cortex homogenate. In addition, the effect of TJ-23 on the concentration of neurotransmitters and TBARS formation, and superoxide dismutase (SOD) activity in the cortex, hippocampus and striatum of the aged rat brain was studied. The concentrations of the metabolites of monoamines, glutamate and glutamine were decreased by 4 weeks of oral administration of TJ-23. The SOD activity of mitochondrial fraction was increased and TBARS formation was significantly suppressed. These results suggest that TJ-23 has an antioxidant action and would have a prophylactic effect against free radical-mediated neurological diseases associated with aging.

3,4-Dihydroxyphenylacetic Acid↗