Biomedical subjects

T Watabe

Publications and source records attributed to T Watabe.

At least 19 recordsLinked to original sources

PubMed1992

[2D MR angiography of the aortic aneurysm--effectiveness of oblique saturation pulses for selective angiogram].

2D time-of-flight MR angiography was performed in 6 cases of thoracic aortic aneurysm. Oblique saturation pulses were used to suppress the signals of the pulmonary artery and SVC, providing excellent selective MR aortograms. 3 dimensional extension of the aneurysm and its relation with cervical branches were easily assessed. It could be possible to replace invasive aortography by this technique.

Aorta, Thoracic↗

PubMed1992

Vitreous, retinal and subretinal hemorrhages associated with von Willebrand's syndrome.

Two patients with von Willebrand's syndrome had intraocular hemorrhages without trauma or neovascularization. A 13-year-old Japanese girl complained of sudden spotted vision in her left eye. Vitreous, peripapillary retinal, and subretinal hemorrhages were seen by ophthalmoscopy in the affected eye. In addition, a 19-year-old Japanese man had repeated vitreous hemorrhage and epistaxis. Also noted was gyrate atrophy of the choroid and retina. Analysis of the coagulation-fibrinolysis system revealed decreased activities of Factor VIII and von Willebrand's factor in both patients. The amount of von Willebrand's factor antigen also was decreased. These results suggested that the patients had von Willebrand's syndrome. The bleeding tendency in the disorder appeared to be responsible for the pathogenesis of the intraocular hemorrhages seen in these patients.

Adolescent↗

PubMed1992

Giant air cell of the petrous apex: a possible cause of facial hypalgesia.

A giant air cell of the left petrous apex was found in a 23-year-old man with ipsilateral facial hypalgesia. The size of the giant air cell depicted on computed tomography was 1.5 x 2.0 x 2.0 cm. A coronal T1-weighted magnetic resonance image showed that the trigeminal nerve was compressed superomedially by a large signal void area that was probably a result of excessive pneumatization of the petrous apex. It is suggested that the facial hypalgesia was caused by the compression by the giant air cell of the petrous apex on the trigeminal nerve.

Adult↗

PubMed1991

Molecular cloning and amino acid sequencing of rat liver class theta glutathione S-transferase Yrs-Yrs inactivating reactive sulfate esters of carcinogenic arylmethanols.

A cDNA containing the entire coding sequence for the subunit protein of rat liver class theta glutathione S-transferase (GST) Yrs-Yrs was isolated from a rat liver lambda gt11 cDNA library. The cDNA, designated GST theta-1, consisted of 1,258 bp which had an open reading frame of 732 bp encoding a polypeptide of 244 amino acid (AA) residues, including the leading AA Met to be removed on expression. The authenticity of the cDNA structure was supported by matching its deduced AA sequence with N-termini of Yrs and peptides obtained thereof by tryptic digestion as well as by CNBr cleavage. The deduced AA sequence of the subunit Yrs (M.W. 27,311) had only a weak homology (19-23%) with those of rat liver classes alpha, mu, and pi GST isozymes. Thus, the first evidence for the molecular cloning of the class theta GST was provided.

Amino Acid Sequence↗

PubMed1991

Occurrence of cholesterol 7 alpha- and 7 beta-hydroperoxides in rat skin as aging markers.

Evidence for presence of cholesterol 7 alpha- and 7 beta-hydroperoxides in rat skin was presented for the first time. The 7-hydroperoxides in rat skin were reduced with sodium borohydride and trimethylsilylated for identification with the authentic compounds by gas chromatography/mass spectrometry. A content of cholesterol 7-hydroperoxides in rat skin, determined by high performance liquid chromatography with a chemiluminescence detector, highly correlated with the age of rats (r = 0.874; between 1 and 45 weeks old), indicating that cholesterol 7 alpha- and 7 beta-hydroperoxides were good markers for aging.

Aging↗

PubMed1991

Reductive metabolism of nitro-p-phenylenediamine by rat liver.

Reductive metabolism of the hair dye constituent, nitro-p-phenylenediamine (2-nitro-1,4-diaminobenzene, NPDA), and its acetylated metabolite, NPDA N4-acetate, was investigated with rat liver subcellular fractions, microsomes and cytosol. Under anaerobic conditions, these compounds were reduced to their corresponding amines by these fractions. The microsomal nitro-reducing activity was retarded completely by air and strongly by carbon monoxide. Reduced nicotinamide adenine dinucleotide phosphate (NADPH) functioned more effectively than reduced nicotinamide adenine dinucleotide (NADH) as an electron donor in the microsomal reduction of the nitro compounds, and flavin mononucleotide (FMN) gave rise to a marked enhancement in the microsomal activity, especially when added to an anaerobic incubation mixture containing both NADH and NADPH. The cytosolic nitro-reducing activity was attributed to xanthine oxidase, aldehyde oxidase and other unknown enzyme(s), based on the results of cofactor requirements and inhibition experiments.

Animals↗

PubMed1991

Ontogeny of corticotrophin-releasing factor (CRF) in the ovine fetal hypothalamus: use of multiple CRF antibodies.

In previous studies, using one particular antibody, immunohistochemical localization of corticotrophin-releasing factor (CRF) in ovine fetal brain was not possible before 90 days of gestation (term is approximately 150 days), although radioimmunoassay of hypothalamic extracts, using a different antibody, had shown CRF to be present from 63 days. The purpose of this study was to use a variety of CRF antibodies in both immunohistochemistry and radioimmunoassay to determine the presence and concentration of the CRF peptide as early in gestation as possible, and to determine whether more than one molecular size of CRF is detectable at any time in gestation. Seven different antibodies were used on hypothalamic tissue or extracts from seven adult sheep and 37 fetuses from 48 to 140 days of gestation. With one ovine CRF antibody (provided by Dr W. Vale, Salk Institute) immunohistochemical detection of CRF-labelled neurones and nerve fibres of the paraventricular nucleus and median eminence was possible from 49 days. The antibody with the greatest sensitivity in radioimmunoassay was one raised against human CRF, Ab-code R1 (provided by Dr E. Hillhouse, University of Newcastle upon Tyne). The hypothalamic contents of CRF (ng/whole hypothalamus) were 0.28 +/- 0.06 (mean +/- S.E.M.) (n = 4), 9.0 +/- 0.6 (n = 5), 14.3 +/- 0.6 (n = 5), 30.0 +/- 3.4 (n = 4) in fetuses at 48-50, 100-109 and 139-140 days of gestation and in adult sheep respectively. At all ages only one peak of CRF-like activity, which co-eluted with synthetic ovine CRF, was observed after chromatography of hypothalamic extracts, and assays performed with three different antibodies.(ABSTRACT TRUNCATED AT 250 WORDS)

Animals↗

PubMed1991

DNA polymerase action blocked by adenine adducts induced by 5-hydroxymethylchrysene sulfate.

Modification of M13mp10 single-stranded DNA with 5-hydroxymethylchrysene (5HCR) sulfate, the ultimate carcinogenic metabolite of 5-methylchrysene, resulted in formation of N6[(chrysen-5-yl)methyl]adenine and N2[(chrysen-5-yl)methyl]-guanine at the ratio of 2.7:1. Measurement of DNA synthesis using this modified template and E.coli DNA polymerase I (Klenow fragment) demonstrated that increasing levels of adducts caused a progressive decline in replication. Analysis of reaction products on DNA-sequence gels revealed DNA elongation to be arrested exclusively at adenine adducts in -AAAGGA- and -AACA- sequences.

Adenine↗

PubMed1990

A new class of rat glutathione S-transferase Yrs-Yrs inactivating reactive sulfate esters as metabolites of carcinogenic arylmethanols.

A glutathione (GSH) S-transferase (GST), catalyzing the inactivation of reactive sulfate esters as metabolites of carcinogenic arylmethanols, was isolated from the male Sprague-Dawley rat liver cytosol and purified to homogeneity in 12% yield with a purification factor of 901-fold. The purified GST was a homo-dimeric enzyme protein with subunit Mr 26,000 and pI 7.9 and designated as Yrs-Yrs because of its enzyme activity toward "reactive sulfate esters." GST Yrs-Yrs could neither be retained on the S-hexylglutathione gel column nor showed any activity toward 1,2-dichloro-4-nitrobenzene, 4-nitrobenzyl chloride, and 1,2-epoxy-3-(4'-nitrophenoxy)propane. 1-Chloro-2,4-dinitro-benzene was a very poor substrate for this GST. 1-Menaphthyl sulfate was the best substrate for GST Yrs-Yrs among the examined mutagenic arylmethyl sulfates. The enzyme had higher activities toward ethacrynic acid and cumene hydroperoxide. N-terminal amino acid sequence of subunit Yrs, analyzed up to the 25th amino acid, had no homology with any of the known class alpha, mu, and pi enzymes of the Sprague-Dawley rat. Anti-Yrs-IgG raised against GST Yrs-Yrs showed no cross-reactivity with any of subunits Ya, Yc, Yb1, Yb2, and Yp. Anti-IgGs raised against Ya, Yc, Yb1, Yb2, and Yp also showed no cross-reactivity with GST Yrs-Yrs. The purified enzyme proved to differ evidently from the 12 known cytosolic GSTs in various tissues of the rat in all respects. Immunoblot analysis of various tissue cytosols of the male rat indicated that apparent concentrations of the GST Yrs-Yrs protein were in order of liver greater than testis greater than adrenal greater than kidney greater than lung greater than brain greater than skeletal muscle congruent to heart congruent to small intestine congruent to spleen congruent to skin congruent to 0.

Amino Acid Sequence↗

PubMed1990

[MR imaging of aortic arch anomalies--an analysis of MR visualization of ductus arteriosus].

MR imaging of 10 patients with aortic arch anomaly was performed on a 1.0 T system. Coronal and sagittal images with a 5 to 6-mm-thick slice were taken in each patient and the visibility of the ductus arteriosus (ductus ligament) was detected on the sagittal images including its anatomical connection between the pulmonary trunk and arch vessel. The result indicates that MR imaging is of great help for detection of the ductus in case of aortic arch anomaly.

Adult↗

PubMed1990

cDNA cloning of the hydroxysteroid sulfotransferase STa sharing a strong homology in amino acid sequence with the senescence marker protein SMP-2 in rat livers.

A cDNA encoding hydroxysteroid sulfotransferase a (STa), which catalyzes activation of carcinogenic polycyclic hydroxymethyl-arenes, was isolated from a lambda gtll cDNA expression library constructed from poly(A)+RNA of a female Sprague-Dawley (SD) rat liver. The cDNA, designated as ST-40, consisted of 1,015 base pairs which had an open reading frame of 852 base pairs encoding the entire rat STa subunit of 284 amino acids. The nucleotide base sequence of the ST-40 cDNA shared a strong homology of 94.4% with that of ST-20 cDNA encoding a hydroxysteroid ST which had been reported by us. The deduced amino acid sequence of STa had a homology of 73.7% with that of an SD rat liver senescence marker protein (SMP-2) consisting of 282 amino acid residues. However, STa was found to share a much stronger homology of 92% on the average with SMP-2 in their four specific regions corresponding to about 60% of the total sequences, indicating SMP-2 to be an isozyme of hydroxysteroid ST.

Amino Acid Sequence↗

PubMed1990

Lack of effect of granulocyte-macrophage colony stimulating factor on the rat aorta or human saphenous vein.

1. In order to assess whether the observed hypotensive response in some patients given human granulocyte-macrophage colony stimulating factor (GM-CSF) is caused by a direct vascular effect of the GM-CSF, the effects of mouse and human GM-CSF were examined in rat aortic rings and human saphenous veins respectively. 2. No effects of GM-CSF were observed, either in the presence or absence of endothelium, on responses to the alpha-adrenoceptor agonist phenylephrine. 3. These data suggest that GM-CSF does not have direct effects on either vascular endothelium or smooth muscle, and that a direct vascular effect of GM-CSF is not the explanation for the observed clinical response.

Animals↗

PubMed1990

Crystallization of R-form lipopolysaccharides from Salmonella minnesota and Escherichia coli.

Salmonella minnesota Re and Ra lipopolysaccharides (LPSs) and Escherichia coli K-12 LPS formed three-dimensional crystals, either hexagonal plates (preferential growth along the a axis) or solid columns (preferential growth along the c axis), when they were precipitated by the addition of 2 volumes of 95% ethanol containing 375 mM MgCl2 and incubated in 70% ethanol containing 250 mM MgCl2 at 4 degrees C for 10 days. Analyses of crystals suggested that they consist of hexagonal lattices with the a axis (a side of the lozenge as a unit cell on the basal plane) of 0.462 nm for all these three kinds of LPSs and the c axes (perpendicular to the basal plane) of 5.85, 8.47, and 8.75 nm for S. minnesota Re and Ra LPSs and E. coli K-12 LPS, respectively, and that hydrocarbon chains of the lipid A portion play the leading part in crystallization, whereas the hydrophilic part of the lipid A (the disaccharide backbone) and R core exhibit a disordered structure or are in a random orientation. The phenomenon of doubling of the a axis to 0.924 nm was observed with crystals of S. minnesota Re LPS when they were incubated in 70% ethanol for an additional 180 days, but not with crystals of S. minnesota Ra LPS or E. coli K-12 LPS. S. minnesota S-form LPS possessing the O-antigen-specific polysaccharide and S. minnesota free lipid A obtained by acid hydrolysis of Re LPS did not crystallize under the same experimental conditions.

Carbohydrate Conformation↗

PubMed1990

Regioselective N-acetylation as a route of nitro-9-phenylenediamine metabolism by rat liver cytosol.

Regioselectivity in N-acetylation of nitro-0-phenylenediamine, a widely used hair dye component, by rat liver cytosolic N-acetyltransferases was studied in relation to its substituent effects on enzymatic N-acetylation of mono-substituted anilines. Nitro-p-phenylenediamine was acetylated specifically at the N4-position to afford the N4-monoacetate, a major urinary metabolite in the rat, when incubated with rat liver cytosol fortified with acetyl-coenzyme A. N1-Acetylation of nitro-p-phenylenediamine did not take place even when the N4-monoacetate was used as a substrate, suggesting a strong steric hindrance effect of the ortho nitro group on the enzymatic N1-acetylation. The steric hindrance effect of the nitro group on the cytosolic N-acetylation of the ortho amino group was revealed by a comparative study carried out by using aniline, three respective regioisomers of nitroanilines and phenylenediamines as model substrates. The comparative study also indicated the enzymatic N-acetylation of the mono-substituted anilines to be strongly influenced by the electronic effect of the substituents. Regioselective N-acetylation in the hepatic cytosol was also investigated with N1- and N4-monoacetates of 1,2,4-triaminobenzene. The monoacetates yielded the N1,N4-diacetate, another major urinary metabolite of the hair dye component, in the rat, without concomitant formation of the N2,N4-diacetate or the N1,N2,N4-triacetate. The triacetate was formed only from the N1,N2-diacetate in the enzymatic reactions. A comparative study, carried out by using N-mono-acetates of three regioisomeric phenylenediamines, indicated that the N-acetyl group had a potent steric hindrance effect on the primary amino group at the ortho position.(ABSTRACT TRUNCATED AT 250 WORDS)

Acetylation↗

PubMed1990

Rat liver cytosolic hydroxysteroid sulfotransferase (sulfotransferase a) catalyzing the formation of reactive sulfate esters from carcinogenic polycyclic hydroxymethylarenes.

Female rat liver cytosol contained at least three sulfotransferases (STs) that were separable on a DEAE-Sephadex A-50 column and transformed the carcinogen 5-hydroxymethylchrysene (5-HCR) to the potent mutagen 5-HCR sulfate. The STs also catalyzed sulfation of dehydroepiandrosterone (DHA), a typical substrate for hydroxysteroid STs. Of these three isozymes, the one (STa) with the highest 5-HCR-sulfating activity was isolated and purified (100-fold) as a homogeneous protein, in 15% yield, by successive column chromatography on agarose modified with 3'-phosphoadenosine 5'-phosphate as an affinity ligand and on Sephadex G-100. Purified STa was classified as a hydroxysteroid ST because the 5-HCR- and DHA-sulfating activities were inseparable from each other throughout the purification steps. Sulfation of 5-HCR by purified STa was competitively inhibited by DHA. STa also catalyzed sulfation of other potent carcinogens, 7-hydroxymethylbenz[a]anthracene, 7-hydroxymethyl-12-methylbenz[a]anthracene, and 7,12-dihydroxymethylbenz[a], anthrocene, to produce sulfate esters with high reactivity and mutagenicity. However, STa had no activity with 4-nitrophenol, a typical substrate for phenol STs, or with N-hydroxy-2-acetylaminofluorene. STa had a pl value of 6.4 and existed on a gel filtration column as a homooligomer of a subunit protein with Mr 30,500, determined by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. The N-terminal amino acid sequence of STa was as follows: Pro-Asp-Tyr-Thr-Trp-Phe-Glu-Gly-Ile-Pro-Phe-Pro-Ala-Phe-Gly-Ile- Pro-Lys-Glu-Thr-. Immunoblot analysis of female and male rat liver cytosol, carried out by using rabbit antiserum raised against the purified enzyme STa and sodium dodecyl sulfate-polyacrylamide gel electrophoresis, indicated that the female liver contained a much higher level of the enzyme than did the male liver. The marked sex difference in STa level was in good accordance with the previous demonstration that cytosol from the liver of female rats catalyzed sulfation of 5-HCR to a greater extent than did cytosol from the liver of male rats.

9,10-Dimethyl-1,2-benzanthracene↗

PubMed1990

Novel type of ornithine-glutathione double conjugate excreted as a major metabolite into the bile of rats administered clebopride.

Rats orally given radioactive Clebopride [[14C]CP; N-(1'-benzyl-4'-piperidyl)-2-[14C]methoxy-4-amino-5-chlorobenzamide++ +], an antiulcer agent, excreted a novel type of ornithine (Orn)-GSH double conjugate in the bile as a major metabolite [( 14C]BMCP), corresponding to 18% of the dose. The present study provides the first evidence for Orn conjugation of a xenobiotic in mammals and demonstrates that the structure of the radioactive conjugate differs fundamentally from those known in birds and reptiles. The structure of the biliary metabolite, [14C]BMCP, purified to homogeneity by silica gel thin layer and reverse phase high pressure liquid chromatography, was elucidated as S-[2-ornithylamino-4-[14C]methoxy-5-(1'-methyl-4'-piperidylamin o) carboxyphenyl]glutathione, based mainly on the following facts: 1) BMCP showed a protonated molecular ion (M + H)+ peak at m/z 683 in the secondary ion mass spectrum and 2) [14C]BMCP afforded Orn, glutamic acid, glycine, S-(2-amino-4-[14C]methoxy-5-carboxyphenyl)cysteine [( 14C]AMCC), and 1-methyl-4-aminopiperidine (MAP) quantitatively, in an equal molar ratio, by complete hydrolysis with peptidase. Thus, BMCP was a metabolite with three enzymatically hydrolyzable amide bonds in addition to the one existing originally in the parent structure of the drug, which produces MAP by peptic digestion. Of the three additional amide bonds of BMCP, one was a novel type of bond formed by condensation of the alpha-carboxylic acid group of Orn with the primary aromatic amino group of the drug and the other two were in the S-glutathionyl residue, substituted for the chlorine atom vicinal to the Orn-conjugating primary amino group in the aromatic ring and affording glutamic acid, glycine, and the S-cysteine conjugate AMCC by hydrolysis of BMCP with the peptidase. Substitution of a methyl group for the benzyl group at the piperidine ring nitrogen atom, leading to the formation of MAP by peptic digestion, also occurred during metabolism of CP to BMCP.

Animals↗

PubMed1989

Glutathione conjugation of styrene 7,8-oxide enantiomers by major glutathione transferase isoenzymes isolated from rat livers.

Male Sprague-Dawley rat liver cytosol mediated regioselective conjugation of styrene 7,8-oxide (STO) enantiomers with glutathione in completely trans-ring-opening manner to afford (1S)-S-(1-phenyl-2-hydroxyethyl)glutathione and (2R)-S-(2-phenyl-2-hydroxyethyl)glutathione in the ratio 22:1 for (R)-STO and also to afford (1R)-S-(1-phenyl-2-hydroxyethyl)glutathione and (2S)-S-(2-phenyl-2-hydroxyethyl)glutathione in the ratio 12:1 for (S)-STO. In the above cytosolic reactions, (R)-STO was conjugated 1.8 times faster than (S)-STO, while the (R)- to (S)-ratio in rate of the conjugation was 2.7 when racemic STO was used as a substrate. A kinetic study, carried out by using six major glutathione transferase (GST) isoenzymes isolated from the cytosol, indicated that GSTs 3-3, 3-4 and 4-4 (class mu enzymes) had much higher Kcat/Km values towards both STO enantiomers than the other three major isoenzymes, GSTs 1-1, 1-2 and 2-2 (class alpha enzymes). All the class mu enzymes mediated preferential glutathione conjugation of (R)-STO to (S)-STO. On the contrary, the class alpha enzymes catalysed the conjugation of (S)-STO preferentially to (R)-STO. The kinetic study strongly suggested that GSTs determining the higher enantioselectivity towards (R)-STO in the rat liver cytosol were the class mu enzymes, especially GST 3-3, which had the highest Kcat/Km value towards (R)-STO as well as the highest (R) to (S) ratio in the enantioselectivity among the six isoenzymes examined. GST 7-7, isolated as a major enzyme from the liver cytosol of the animals bearing hepatic hyperplastic nodules which were induced by chemical carcinogens, catalysed preferential GSH conjugation of (S)-STO to (R)-STO.

Animals↗

PubMed1989

Cloning and sequence analysis of a rat liver cDNA encoding hydroxysteroid sulfotransferase.

Nothing has been known of the cDNAs encoding sulfotransferases (STs) that catalyze sulfation of steroids and xenobiotics. In the present study, a female Sprague-Dawley (SD) rat liver cDNA library was screened with rabbit anti-serum raised against hydroxysteroid ST a (STa) purified from female SD rat liver cytosol. The cDNA isolated from the library consisted of 1,028 base pairs which had an open reading frame of 852 base pairs encoding the entire rat ST subunit of 284 amino acids. The N-terminal amino acid sequences of STa and the rat liver hydroxysteroid ST, bile acid ST I, both elucidated previously by the chemical method, had a strong homology with that deduced from the cDNA. Northern blot analysis of total RNAs from female and male rat livers showed a marked sex difference (female much greater than male) in the expressed level of the mRNA for the predicted ST subunit protein. A remarkable sex difference (female much greater than male) was also observed by immuno-blot analysis in the level of the hydroxysteroid ST protein(s) cross-reacting with the anti-serum in the rat liver cytosols.

Amino Acid Sequence↗