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Y Oda

Publications and source records attributed to Y Oda.

At least 451 records · Page 25Linked to original sources
PubMed1992

Use of a newly developed tester strain Salmonella typhimurium NM2009 for the study of metabolic activation of carcinogenic aromatic amines by rat liver microsomal cytochrome P-450 enzymes.

Using an O-acetyltransferase-overexpressing strain Salmonella typhimurium NM2009 we measured the activities for metabolic activation of several carcinogenic arylamines to genotoxic products by rat liver microsomal cytochrome P-450 enzymes, and compared them with the activities obtained in the original tester strain Salmonella typhimurium TA1535/pSK1002 or the O-acetyltransferase-defective strain Salmonella typhimurium NM2000. Since all of the tester strains had introduced the umuC'-'lacZ gene, we could detect the genotoxic activities by measuring bacterial beta-galactosidase activity resulting from the DNA damage. In the O-acetyltransferase-defective strain NM2000 most of the arylamines tested showed weak responses in inducing umu gene expression after metabolic activation by liver microsomes. The strain NM2009, on the other hand, was found to be highly sensitive towards a variety of aromatic amines, and these activities were greater than those seen in the original tester strain S. typhimurium TA1535/pSK1002. The chemicals which marked responses in strain NM2009 include 2-aminoanthracene, 6-aminochrysene, 2-aminofluorene, 2-acetylaminofluorene, 3-methoxy-4-aminoazobenzene, O-aminoazotoluene, Glu-P-1, Trp-P-2, A alpha C, MeA alpha C, MeIQ, MeIQx and IQ. Of these procarcinogens tested MeIQ, MeIQx and IQ also showed strong cytotoxic effects in S. typhimurium NM2009 after metabolic activation by liver microsomes. Only PhIP was the substrate showing similar responses in strains TA1535/pSK1002 and NM2009. The results with the reconstituted monooxygenase system containing purified cytochrome P-450 enzymes support the above findings obtained with the liver microsomal enzyme system. Thus, the usefulness of the newly developed strain NM2009 for the detection of reactive metabolites of several carcinogenic aromatic amines after metabolism by the liver microsomal cytochrome P-450-linked monooxygenase system has been ascertained.

Amines↗
PubMed1992

A complementary DNA for human choline acetyltransferase induces two forms of enzyme with different molecular weights in cultured cells.

Complementary DNA (cDNA) clones containing the entire coding region of human choline acetyltransferase (ChAT) were isolated from cDNA libraries prepared from the autopsied spinal cord. In the human cDNA, the ATG codon assigned to the putative initiation codon for pig, rat and mouse ChAT cDNAs was replaced by ACG. The human cDNA contained an in-frame ATG codon 324 nucleotides upstream of the ACG codon. Therefore, human ChAT cDNA should code for a 748 amino acid polypeptide of 82.6 kDa. This deduced molecular weight was larger than that of ChAT protein purified from the human brain and placenta (64-70 kDa). The human ChAT cDNA containing the entire coding region was ligated to an expression vector and introduced into African green monkey kidney (COS) cells and Chinese hamster ovary (CHO) cells. The cells expressed high ChAT activity and produced two protein bands immunostained with an antibody to monkey ChAT. The molecular weight of the proteins was estimated to be approximately 70 and 80 kDa by polyacrylamide-SDS gel electrophoresis. When partial cDNAs that lacked the first ATG but contained the replaced ACG codon were introduced into COS cells, the cells expressed moderate ChAT activity and an immunoreactive protein band of 70 kDa. These results indicate that translation of human ChAT mRNA starts at two sites and produces two enzyme proteins with different molecular weights. It might be that the larger form of ChAT molecule is an enzyme precursor for processing or that the N-terminal extrapeptide is needed for subcellular localization of the enzyme.

Amino Acid Sequence↗
PubMed1992

On-line determination and resolution of the enantiomers of ketoprofen in plasma using coupled achiral-chiral high-performance liquid chromatography.

High-performance liquid chromatography (HPLC) using a column-switching technique has been applied to the on-line determination and resolution of the enantiomers of ketoprofen (KPF) as an acidic model compound. The system incorporates a mobile phase conversion stage (LC-2), which has a dilution tube and a trapping column, between the achiral chromatography stage (LC-1) and the chiral chromatography stage (LC-3). KPF in plasma was separated from plasma components and was determined with the aid of an internal standard in LC-1. The eluate containing KPF was selectively transferred to LC-2, where the eluate was adequately diluted with a new mobile phase by using the dilution tube to reduce the influence of the mobile phase from LC-1, and KPF was reconcentrated on the trapping column. Then the KPF enantiomers were resolved in LC-3 after column-switching. This system is accurate and rapid compared with conventional HPLC. Very high sensitivity could be achieved with our system when a microbore ovomucoid column was employed in LC-3. Incorporation of LC-2 allows the most favourable mobile phases for LC-1 and LC-3 to be used independently. This method is greatly superior to usual column-switching HPLC.

Chromatography, High Pressure Liquid↗
PubMed1992

Participation of rat liver cytochrome P450 2E1 in the activation of N-nitrosodimethylamine and N-nitrosodiethylamine to products genotoxic in an acetyltransferase-overexpressing Salmonella typhimurium strain (NM2009).

The possible roles of cytochrome P450 (P450) enzymes in the metabolic activation of N-nitrosodimethylamine (NDMA) and N-nitrosodiethylamine (NDEA) by rat liver microsomes have been examined in a system containing the bacterial tester strain Salmonella typhimurium NM2009, a newly developed strain showing high O-acetyltransfer activities. The DNA-damaging activity could be determined by measuring expression of the umu gene in a plasmid containing the fused umuC-lacZ gene construct in the bacteria. The following lines of evidence support the view that both NDMA and NDEA are principally oxidized to reactive products by P450 2E1 in rat liver microsomes. First, NDMA and NDEA were activated by rat liver microsomes in a protein- and substrate-dependent manner and the former chemical was more active than the latter; both activities were induced in rats treated with P450 2E1 inducers such as ethanol, acetone and isoniazid and by starvation. Second, activation of NDMA and NDEA were both inhibited significantly by antibodies raised against rat P450 2E1 and by P450 2E1 inhibitors such as diethyldithiocarbamate and 4-methylpyrazole in rat liver microsomes. Finally, in reconstituted monooxygenase systems containing purified rat P450 enzymes, P450 2E1 gave the highest rates of the activation of both NDMA and NDEA; the addition of rabbit cytochrome b5 to the system caused about a 1.5-fold increase in both reactions. In separate experiments we also found that N-nitrosomethylacethoxymethylamine, a compound that reacts with DNA after ester cleavage, is more genotoxic in S.typhimurium NM2009 than in S.typhimurium NM2000, a strain that is defective in O-acetyltransferase activity. Part of the pathway involved in the activation of nitrosamines is suggested to be acetylation of alkyldiazohydroxides formed by P450 or acetylesterase, because the genotoxic activity of N-nitrosomethylacethoxymethylamine in S.typhimurium NM2009 could be inhibited by the O-acetyltransferase inhibitor pentachlorophenol. These results indicate that NDMA and NDEA are oxidized to gentoxoic products by rat liver microsomes and that a P450 2E1 enzyme plays a major role in the activation of these two potent carcinogens. The activation pathway of N-nitrosodialkylamines through acetylation by O-acetyltransferase has been proposed. This simple bacterial system for measuring genotoxicity should facilitate studies on the activation of N-nitroso alkylamines.

Acetyltransferases↗
PubMed1992

Collagenous and basement membrane proteins of chordoma: immunohistochemical analysis.

Tissue localization of collagenous and basement membrane proteins in the extracellular matrix of five sacro-coccygeal chordomas and human fetal notochords was examined immunohistochemically to assess the implications for the histogenesis and histological diagnosis of chordoma. Human fetal notochords and conventional chordomas both exhibited basement membrane proteins (such as type IV collagen and laminin) and type VI collagen on the surfaces of cellular cords. Type II collagen, a main structural protein of cartilage, was also present in both tissues. In the chordomas, however, type II collagen was not so widespread as it was in the notochords, and the predominant collagenous protein was type I. In contrast, an altered deposition of these proteins was noticed in a recurrent tumour which, histologically, showed considerable atypia and eventually metastasized to the liver. The characteristic cartilage-type and basement membrane proteins disappeared and unusual collagen types, such as types III and V, appeared in the stroma. The results further support the notochordal origin of chordoma and suggest that the immunohistochemistry of collagenous and basement membrane proteins may be a helpful criterion for the histological diagnosis and prediction of the biological aggressiveness of chordomas.

Adult↗
PubMed1992

Two children with bromate intoxication due to ingestion of the second preparation for permanent hair waving.

We report two children who suffered from sodium bromate intoxication due to ingestion of the second preparation for permanent hair waving (the second permanent preparation). One child suffered from gastrointestinal symptoms only. The other exhibited slight acute renal insufficiency. Results of the histological examination of the kidney in the sick child with acute renal insufficiency showed sporadic epithelial separation of the proximal tubuli under light microscopy. In addition, we could demonstrate more clearly epithelial separation and unbroken tubular basement membranes under electron microscopy (EM). To our knowledge, this is the first report of EM findings in this disease. The mechanism of epithelial injuries by bromate is not clear.

Acute Kidney Injury↗
PubMed1992

Collagens in human atherosclerosis. Immunohistochemical analysis using collagen type-specific antibodies.

This study represents a systematic analysis of the distribution of collagen types in human atherosclerotic lesions. Formalin-fixed, paraffin-embedded aortic tissues of 40 lesions from 16 different individuals ranging in age from 1 month to 84 years were examined immunohistochemically using antibodies to type I, III, IV, V, and VI collagens. Preembedding immunoelectron microscopy was used to simultaneously localize type V and VI collagens within the lesions. Localization of type III collagen was very similar to that of type I, and type VI collagen appeared together with these two types of collagen in the thickened intimas of all stages of the lesion. Type V collagen was not detected in either fatty streaks or the mild intimal thickening of the aortas of children. With advancing age and lesion progression, the immunoreactivity with anti-type V collagen antibody became more intense. Type IV collagen was detected in the basement membrane region of intimal cells. In advanced lesions thick deposits of type IV collagen were found around the elongated smooth muscle cells. Using immunoelectron microscopy, type V collagen was found to be localized to cross-banded collagen fibers, and type VI collagen was found to be localized to beaded filaments present throughout the interstitium of the thickened intima. These findings suggest that collagens preserve the pathophysiological and functional integrity of the vascular wall by providing mechanical support as well as assuring the proper interaction of cells during the formation of atherosclerotic lesions.

Adult↗
PubMed1992

Establishment of a new cell line derived from a human gliosarcoma.

A permanent cell line, GI-1, was established from a human gliosarcoma, and its characteristics were investigated. The original tumor was a mixture of two different neoplasms which had components of both glioma and sarcoma. The established cell line expressed various mesenchymal antigens, but not neuroepithelial antigens. It was noted, however, that the cell line produced tumors with the morphological features of human glioma after inoculation in athymic mice. The contrast of the pathological characteristics in tissue culture and in xenograft was unique, and this finding suggests that the GI-1 cell line may have the features of both glioma and sarcoma.

Aneuploidy↗
PubMed1992

Human glioma-specific antigens detected by monoclonal antibodies.

Three murine monoclonal antibodies, designated GA-17, GB-4, and GC-3, were prepared by the hybridization of murine myeloma cells (NS-1) and spleen cells of BALB/c mice immunized with the crude membrane fraction of cultured human gliosarcoma cells (GI-1). Two of them (GA-17 and GB-4) reacted exclusively with the membrane of glioma cells, and the other (GC-3) reacted with the membrane of glioma cells and a T cell line (MOLT-4). Although these antibodies reacted with almost all of the gliomas, the reactions differed. GA-17 reacted equally well with all glioblastoma (17 cases) and low-grade astrocytoma (10 cases), whereas GB-4 reacted poorly with 7 cases of glioblastoma and GC-3 did not react with 7 cases of low-grade astrocytoma. The antigens, exclusively expressed on the cell surface, were analyzed by surface labeling with 125I followed by a cell lysis and immunoprecipitation with these antibodies. The findings obtained by sodium dodecyl sulfate-polyacrylamide gel electrophoresis revealed that GA-17, GB-4, and GC-3 reacted with Mr 140,000-145,000, Mr 160,000, and Mr 145,000-150,000 proteins, respectively. Some evidence has been obtained indicating that these antigens are composed of the same polypeptide chain (Mr 120,000) with the carbohydrate chains being different.

Animals↗
PubMed1992

Mechanism of interferon gamma-induced protection of human gliosarcoma cells from lymphokine-activated killer lysis: division of lymphokine-activated killer cells into natural killer- and T-like cells.

The mechanism by which interferon gamma (IFN-gamma) decreases the susceptibility of the established cultured gliosarcoma line Gl-1 to lymphokine-activated killer (LAK) lysis was analyzed. The results of monolayer depletion and lectin-dependent cellular cytotoxicity assays by LAK cells revealed that the resistance to LAK lysis of IFN-gamma-treated Gl-1 cells is manifested at the stage of LAK cell target recognition alone. We have also divided LAK cells into populations of phenotypically natural killer (NK)- and T-like cells with monoclonal antibodies and complement, respectively. We have used these cells to examine the mechanism of IFN-gamma-induced protection of Gl-1 cells from LAK lysis in cold target inhibition, monolayer depletion, and direct binding assays. The results revealed that NK-like cells do not recognize IFN-gamma-treated Gl-1 cells as efficiently as they do untreated targets, whereas T-like cells show the opposite tendency. In conclusion, we have demonstrated that the IFN-gamma induced protection of tumor cells from LAK lysis is predominantly regulated by the target recognition of NK-like cells. On the other hand, IFN-gamma-treated tumor cells may bind to T-like cells but fail to trigger them to initiate further stages for lysis as effectively as NK-like cells.

Cell Division↗
PubMed1992

Correlation of basic fibroblast growth factor expression levels with the degree of malignancy and vascularity in human gliomas.

Basic fibroblast growth factor (FGF) is a mitogen, a differentiation factor for neuroectoderm-derived cells, and a potent angiogenic factor. The authors have previously demonstrated that the messenger ribonucleic acid of basic FGF is expressed in more than 90% of human gliomas. In the present study, they examined the expression of basic FGF in human glioma tissues using immunohistochemical techniques with a mouse monoclonal antibody against human basic FGF. They also correlated the basic FGF level with the histological grades of malignancy assessed by the number of nucleolar organizer regions (NOR's). Basic FGF was detected in 18 of 19 gliomas, whereas it was undetectable in two normal brains. The expression level of basic FGF peptide increased proportionally with the degree of malignancy. There was also a tendency for the number of NOR's in glioma cells to increase in glioma samples with a high level of basic FGF expression. Furthermore, most of the cases with increased vascularity demonstrated on cerebral angiograms showed a relatively high level of basic FGF expression of tumor cells and a large number of NOR's in endothelial cells in tumor tissues. These results suggest that basic FGF is actually produced in most gliomas and is involved in tumorigenesis and malignant progression as an autocrine growth factor. Moreover, basic FGF may play an important role in tumor neovascularization as a paracrine angiogenic factor.

Animals↗
PubMed1992

[A case of systemic lupus erythematosus associated with Sjögren's syndrome diagnosed by lung localization].

A 30-year-old female, diagnosed as having SLE and followed at our hospital while receiving oral prednisolone (5 mg/day) for about 6 months, was admitted because of fever and productive cough. Chest X-ray and CT scan showed a tumor-like homogeneous shadow in the right middle lobe. Antibiotic treatment was not effective. Specimens obtained by TBLB revealed massive infiltration of mature plasma cells and lymphocytes into the alveolar septa and interstitial tissues. These findings were considered compatible with lymphoid interstitial pneumonia. Associated conditions such as Sjögren's syndrome were suggested, but the diagnostic criteria of Sjögren's syndrome were not satisfied. Both the abnormal shadow on chest X-ray and the clinical symptoms markedly improved by increasing the dose of prednisolone (20 mg/day). After 3 months, however, bilateral BAL findings showed alveolar lymphocytosis, providing evidence that subclinical diffuse pulmonary involvement had continued. This case indicates that radiological appearance may vary depending on the extent of lung involvement, even if the histological features are identical. It is concluded that the present diagnostic criteria of Sjögren's syndrome must be reconsidered so as not to overlook subclinical and asymptomatic cases of Sjögren's syndrome.

Adult↗
PubMed1992

[Effect of intravenous pirenzepine on hemodynamics and gastric juice volume as well as pH in surgical patients].

The effects of pirenzepine on blood pressure, heart rate and gastric juice volume as well as pH were evaluated and compared with those after atropine and cimetidine in 54 adult patients divided into five groups. Patients in Groups A, P, AP, AC and ACP received atropine, pirenzepine, atropine plus pirenzepine, atropine plus cimetidine, or atropine, cimetidine plus pirenzepine, respectively. Atropine 0.5 mg and cimetidine 200 mg were given intramuscularly 60 min before induction of anesthesia, and pirenzepine 10 mg was given intravenously 5 min before induction. Gastric juice was aspirated just after, 60 and 120 min after induction of anesthesia. Mean blood pressure and heart rate remained unchanged following intravenous pirenzepine in Group P, whereas heart rate increased significantly in Groups AP and ACP. There were no significant differences in mean volume and pH of gastric juice among the groups just after and 120 min after induction of anesthesia, although gastric volume in Group AC was significantly less than in Groups P, AP and ACP 60 min after induction. Gastric pH increased gradually and gastric volume decreased slightly following intravenous pirenzepine. The incidence of samples with a pH higher than 2.5 was greater in Group AC than in Group P just after and 60 min after induction, whereas there was no difference between the two groups after 120 min. We conclude that intravenous pirenzepine 10 mg is effective to reduce gastric juice volume and acidity, and it should be given at least 60 min before induction of anesthesia.

Adult↗
PubMed1992

[Two cases of renal oncocytoma].

Two cases of renal oncocytoma are reviewed. A 67-year-old man and a 21-year-old man with a right renal mass were incidentally revealed by echography. Selective renal angiogram showed no spoke-wheel configuration of vessels in either case. Both cases were pathologically diagnosed as oncocytomas, constructed of large eosinophilic cells with granular cytoplasm and small regular nuclei. The electron micrograph showed cytoplasm packed abundantly with mitochondria. The two patients are in good condition 2.5 and 1.5 years after diagnosis.

Adenoma↗
PubMed1991

How does RNase H recognize a DNA.RNA hybrid?

The mechanism of RNase H substrate recognition is proposed from a model of a chemically modified DNA.RNA hybrid Escherichia coli RNase H complex. Site-directed mutagenesis of the enzyme and substrate titration observed by heteronuclear two-dimensional NMR spectra have been carried out. A model complex has been built, based on free structures of the enzyme and the substrate independently determined by x-ray crystallography and NMR distance geometry, respectively. In addition to steric and electrostatic complementarities between the molecular surfaces of the enzyme and the minor groove of the hybrid in the model, putative hydrogen bonds between the polar groups in the enzyme and 2'-oxygens of the RNA strand of the hybrid fix the hybrid close to the active site of the enzyme. The enzymatic activities of the mutant proteins and the changes in NMR spectra during the course of substrate titration are consistent with the present model. Moreover, the specific cleavage of the RNA strand in DNA.RNA hybrids can be explained as well as cleavage modes in modified heteroduplexes. A mechanism of enzymatic action is proposed.

Amino Acid Sequence↗
PubMed1991

Avidin protein-conjugated column for direct injection analysis of drug enantiomers in plasma by high-performance liquid chromatography.

A new concept in high-performance liquid chromatography supports is proposed for the direct injection analysis of drug enantiomers in plasma. The new supports are designed with disuccinimidyl suberate as a hydrophobic internal region, and avidin protein as a hydrophilic and bulky surface region. Plasma proteins are excluded by the avidin phase and are eluted immediately from the column, whereas low-molecular-mass analytes can penetrate the surface region and interact with disuccinimidyl suberate. Enantiomers interact differentially with avidin, and are thereby separated. This column was used in reversed-phase high-performance liquid chromatographic analysis to determine ketoprofen enantiomers in plasma by direct injection. The recovery of racemic drug from plasma was almost 100%.

Acetonitriles↗
PubMed1991

Expression of the RAG-2 gene in murine central nervous system tumor cell lines.

Two tightly linked recombination activating genes, RAG-1 and RAG-2, are involved in VDJ recombination of the immune system. Although these genes were originally thought to be expressed exclusively in precursor B and T cells, RAG-1 transcripts were recently found in the murine central nervous system (CNS) [Chun et al., Cell 6, 189, (1991)]. We found that the RAG-2 gene was expressed in CNS tumor cell lines, melanoma (B-16) and skin fibroblast (A9). RAG-1 expression was not found in any non-lymphoid cell lines examined including CNS tumor cell lines. Another VDJ recombination-related gene RBP-Jk was expressed in all tumor cell lines examined. It remains to be seen whether expression of RAG-1 and RAG-2 in CNS is abortive or functionally important.

Animals↗