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T Tanimoto

Publications and source records attributed to T Tanimoto.

At least 199 records · Page 11Linked to original sources
PubMed1991

Localization, isolation and properties of three NADPH-dependent aldehyde reducing enzymes from dog kidney.

Three kinds of NADPH-dependent aldehyde reducing enzymes were present in the dog kidney. Aldose reductase was located in the inner medulla region and aldehyde reductase in all regions of the renal cortex, outer medulla and inner medulla. In addition, a new reductase designated tentatively as high-Km aldose reductase, which was converted into an aldose reductase-like enzyme, was present in the inner medulla region of the kidney. Aldose reductase, aldehyde reductase and high-Km aldose reductase were purified to homogeneity from each region of the dog kidney. The molecular weight of aldose reductase was estimated to be 38,500 by SDS-polyacrylamide gel electrophoresis and the isoelectric point was found to be 5.7 by chromatofocusing. Aldose reductase had activity for aldo-sugars such as D-xylose, D-glucose and D-galactose as substrates and utilized both NADPH and NADH as coenzymes. Sulfate ions resulted in over 2-fold activation of aldose reductase. All aldehyde reductases from the three regions had the same properties. The molecular weights and isoelectric points of aldehyde reductases were 40,000 and 6.1, respectively. The aldehyde reductases were inactive for D-hexose, utilized only NADPH as coenzyme and were not affected by sulfate ions. High-Km aldose reductase had a molecular weight of 38,500 and an isoelectric point of 5.4. It had activity for aldo-sugars, but showed much higher Km and lower kcat/Km values than aldose reductase. Sulfate ions inhibited high-Km aldose reductase. It was converted into an aldose reductase-like enzyme by incubation in phosphate buffer at pH 7.0. The three kinds of enzymes were strongly inhibited by the known aldose reductase inhibitors. However, aldehyde reductase and high-Km aldose reductase were, in general, less susceptible than aldose reductase.

Alcohol Dehydrogenase↗
PubMed1991

Purification and characterization of the recombinant human aldose reductase expressed in baculovirus system.

Large quantities of recombinant human aldose reductase were produced using Spodoptera frugiperda cells and properties of the enzyme were characterized. Direct purification of the recombinant aldose reductase by affinity column chromatography using Matrex gel orange A yielded a single 36 kDa band, similar in size to the purified human muscle aldose reductase, on a sodium dodecyl sulfate-polyacrylamide gel after silver staining. The isoelectric point of the recombinant enzyme was 5.85 which is identical to the human muscle aldose reductase. Following the treatment with an acylamino-acid releasing enzyme, the blocked NH2-terminal amino acid was identified to be acetylalanine. The successive NH2-terminal sequence and that of the COOH-terminal peptide concurred with the expected translated sequence. Kinetic analyses of the recombinant enzyme activity for various substrates and the cofactor, NADPH, demonstrated a good agreement with the previously reported kinetic data on the purified human aldose reductase. A high concentration of (NH4)2SO4 elicited a significant increase in both Km and Kcat for DL-glyceraldehyde as well as D-glucose. Although IC50 values for most of the aldose reductase inhibitors with recombinant enzyme were found to fall within the comparable range of those obtained with nonhuman mammalian enzymes, the IC50 value for epalrestat was more than 10-fold higher in the recombinant enzyme. These results indicate that the recombinant human aldose reductase expressed in the baculovirus system possesses structurally and enzymatically similar properties as those reported for the native human enzyme and should serve as a superior enzyme preparation to nonhuman mammalian enzymes for the screening of the efficacy and potency of newly developed aldose reductase inhibitors.

Aldehyde Reductase↗
PubMed1991

Denitrification by the fungus Fusarium oxysporum and involvement of cytochrome P-450 in the respiratory nitrite reduction.

From conditions for production in Fusarium oxysporum of the unique nitrate/nitrite-inducible cytochrome P-450, tentatively called P-450dNIR, it was expected that the fungus is capable of metabolizing nitrate dissimilatively. Here we report that F. oxysporum exhibits a distinct denitrifying ability which results in the anaerobic evolution of nitrous oxide (N2O) from nitrate or nitrite. Comparison of the cell growth during denitrification indicated that the dissimilatory reduction of nitrate to nitrite is an energetically favorable process in F. oxysporum; however, further reduction of nitrite to N2O might be energy-exhausting and may function as a detoxification mechanism. A potent nitrite reductase activity to form N2O could be reconstituted by combination of the cell-free extract prepared from the denitrifying cells and an NADH-phenadinemethosulfate-dependent reducing system. The activity was strongly inhibited by carbon monoxide, cyanide, oxygen (O2), and the antibody against P-450dNIR. The results, along with those concerning inducing conditions of P-450dNIR, were highly indicative that the cytochrome is involved in the denitrifying nitrite reduction. This work has thus presented not only the first demonstration that a eukaryote exhibits a marked denitrifying ability, but also the first instance of a cytochrome P-450 that is involved in a reducing reaction with a distinct physiological significance against a hydrophilic, inorganic substrate.

Cytochrome P-450 Enzyme System↗
PubMed1991

Determination of non-protein-bound iron in rat tissue by ion chromatography with electrochemical detection.

A new, rapid, sensitive, and specific method combining ion chromatography with electrochemical detection was developed for measuring non-protein-bound Fe(II) and Fe(III) in biological samples. The procedure was based on the separation of the iron-diethylenetriaminepentaacetic acid complex formed directly on the chromatographic column with anion-exchange resin followed by electrochemical detection. The method enabled more than 0.5 microM Fe(II) and Fe(III) to be determined for injection volumes of 10 microliters. This method was applicable for the determination of Fe(II) and Fe(III) in ultrafiltrates of the rat liver cytosolic fraction. It was found that release of iron from iron-bound proteins was pH dependent and that non-protein-bound iron in the tissues was determined in a ferrous state at low pH values.

Animals↗
PubMed1991

Purification and characterization of human testis aldose and aldehyde reductase.

1. Aldose reductase and aldehyde reductase were purified to homogeneity from human testis. 2. The molecular weight of aldose reductase and aldehyde reductase were estimated to be 36,000 and 38,000 by SDS-PAGE, and the pI values of these enzymes were found to be 5.9 and 5.1 by chromatofocusing, respectively. 3. Aldose reductase had activity for aldo-sugars, whereas aldehyde reductase was virtually inactive for aldo-sugars. The Km values of aldose reductase for D-glucose, D-galactose and D-xylose were 57, 49 and 6.2 mM, respectively. Aldose reductase utilized both NADPH and NADH as coenzymes, whereas aldehyde reductase only NADPH. 4. Sulfate ion caused 3-fold activation of aldose reductase, but little for that of aldehyde reductase. 5. Sodium valproate inhibited significantly aldehyde reductase, but not aldose reductase. Aldose reductase was inhibited strongly by aldose reductase inhibitors being in clinical trials at concentrations of the order of 10(-7)-10(-9) M. Aldehyde reductase was also inhibited by these inhibitors, but its susceptibility was less than aldose reductase. 6. Reaction of aldose reductase with pyridoxal 5'-phosphate (PLP) resulted ca 2.5-fold activation, but aldehyde reductase did not cause the activation. PLP-treated aldose reductase has lost the susceptibility to aldose reductase inhibitor.

Alcohol Dehydrogenase↗
PubMed1991

CYP52 (cytochrome P450alk) multigene family in Candida maltosa: molecular cloning and nucleotide sequence of the two tandemly arranged genes.

Southern blot analysis under low-stringency conditions using a previously isolated n-alkane-inducible cytochrome P450 (P450alk) gene as a probe revealed the presence of multiple P450alk-related genes in the genome of Candida maltosa. Nine P450alk-related genes (one reported previously and eight in the present report) were isolated from a genomic library constructed from this strain, and these were classified on the basis of sequence similarities into three pairs of putative allelic genes and three nonallelic genes. Two pairs of these alleles were tandemly arranged in the genome. The complete nucleotide sequences of one of these pairs were determined and compared to other members of this P450 family (CYP52) in C. maltosa and C. tropicalis. Northern blot analysis further showed that these genes were regulated by carbon sources. These results provide evidence for a P450alk (CYP52) multigene family in C. maltosa.

Amino Acid Sequence↗
PubMed1991

Characterization of contaminants in EMS-associated L-tryptophan samples by high-performance liquid chromatography.

To identify chemical contaminant(s) associated with eosinophilia-myalgia syndrome (EMS), case and control lots of tryptophan were analyzed by HPLC with both UV and FL detection. Numerous contaminant peaks appeared on the chromatograms and some of them were identified as 5-hydroxytryptophan, indol aldehyde, indol, etc; from the retention time of authentic compounds. Among these, three peaks were significantly associated with case lots. One corresponds to di-tryptophan aminal of aldehyde (peak E). Others are unknown contaminants, UV-5 (FL-7) and UV-28 (FL-36). The structural elucidation and toxicological implication of UV-5 (FL-7) are currently in progress.

Chromatography, High Pressure Liquid↗
PubMed1991

Coagulopathy in chronic subdural hematoma.

Coagulation factors were studied in 30 fluids aspirated from 25 patients with chronic subdural hematoma. Compared with the normal range for plasma, the hematoma fluids demonstrated a marked reduction in factors II, V, VII, VIII, and X, moderate reduction of factors IX and XI, and slight reduction of XII. Factor VII and IX inhibitors were not present or negligible. Activated protein C and antithrombin III were decreased and fibrinopeptide A was markedly increased. No case had a basic disorder causing these abnormal data spontaneously. The decrease in activated protein C possibly caused the marked reduction of factor VIII, therefore the intrinsic and extrinsic clotting pathways were affected differently. The results show excessive activation of coagulation, predominantly via the extrinsic clotting pathway in hematoma, suggesting its importance in the growth of chronic subdural hematoma.

Aged↗
PubMed1991

Evidence that more than one gene encodes n-alkane-inducible cytochrome P-450s in Candida maltosa, found by two-step gene disruption.

An n-alkane-assimilating yeast, Candida maltosa, has a diploid genome. Probed with the previously isolated gene of n-alkane-inducible cytochrome P-450 (P-450alk), its allelic gene had been isolated, its nucleotides sequenced, and the interallelic divergence examined. Using one of the allelic genes, we disrupted the two alleles of the cytochrome P-450alk gene by a two-step gene disruption system. Surprisingly, the disruptant still assimilated n-alkane and contained n-alkane-inducible cytochrome P-450. This result indicates that, other than the disrupted two alleles, there is at least one other gene that encodes an n-alkane-inducible cytochrome P-450.

Alkanes↗
PubMed1991

[Transesophageal Doppler echocardiographic imaging and blood flow measurements for the diagnosis of stenotic left coronary arteries].

To evaluate the usefulness of transesophageal Doppler echocardiography (TEE) in diagnosing left coronary artery (LCA) stenosis, we studied 26 patients with 33 proximal LCA lesions, including 5 with lesions of the left main trunk (LMT), 21 proximal anterior descending arteries (LAD), 7 proximal circumflex arteries (LCx), and 20 with normal coronary arteries. We measured blood flow velocity along the LCA using the pulsed Doppler mode (PD) and obtained velocities at multiple neighboring sites in 13 normal coronary arteries and in 12 of 26 LMTs or LADs with lesions. In all 13 normals, peak velocity tended to decline towards the periphery. By contrast, in one LMT and 10 LADs with lesions, marked increase in peak velocity (1.7 to 3.9 times) was observed at the sites diagnosed as stenotic lesions by coronary angiography. Using two-dimensional echocardiography (2DE), 24 LMTs including 3 with lesions, 4 LADs including 3 with lesions and 13 LCxs including 4 with lesions were imaged. Among them, 3 LMT, one LAD and 2 LCx lesions were correctly diagnosed. The diagnostic ratio by both PD and 2DE was 60% for LMT (PD: 20%, 2DE: 60%), 48% for LAD (PD: 48%, 2DE: 5%) and 29% for LCx (PD: 0%, 2DE: 29%) lesions. In conclusion, TEE proved to be useful in diagnosing proximal LCA stenosis. The coronary flow measurement by PD especially has the potentiality for the diagnosis of proximal LAD stenosis.

Adult↗
PubMed1991

[The influence of aging on the development of rat galactosemic cataract].

In order to investigate the effect of age on the rat galactosemic cataract, 3, 6, 12 and 24-week-old rats were fed with a 50% galactose diet. The cataractous lenses were observed by light microscopy, and the amount of galactitol measured. All rats fed with 50% galactose developed cataracts in the equatorial region. However, the morphological and biochemical development of the galactose cataract in old rats was slower than in young rats. These results suggested that older diabetic patients are less likely to develop diabetic cataract than younger patients.

Aging↗
PubMed1991

[Imaging of coronary arteries and measurement of coronary flow using transesophageal Doppler echocardiography: a comparison with transthoracic Doppler echocardiography].

Recent advances in Doppler echocardiographic techniques, especially using transesophageal approach, enable us to observe coronary arteries and their blood flow. However, the advantages of transesophageal approach in the evaluation of coronary artery are indistinct. The aim of this study was to examine the ability of transesophageal Doppler echocardiography (TED) and transthoracic Doppler echocardiography (TTD) to visualize coronary artery and measure its flow. The study population consisted of 17 healthy subjects and 41 patients with heart diseases (arrhythmia in 2, valvular disease in 10, ischemic heart disease without complete or subtotal obstruction of coronary artery in 22, congenital heart disease in two, cardiomyopathy in four, and infective endocarditis in one). Thirty subjects were examined by TED, and 44 subjects were examined by TTD. Two patients with complete obstruction of the proximal right coronary artery (RCA), who were not included in the above-mentioned subjects, were examined by TED. The results were as follows: 1) The detection rate of coronary arteries by TED and TTD were: left main trunk (LMT); 96.7/86.4%, left anterior descending artery (LAD) and left circumflex artery (LCx); 83.3/56.8%, and RCA; 63.3/38.6%, respectively. 2) Visible length from the orifice: LMT to LAD; 22.2/30.8 mm, RCA; 20.4/22.3 mm. 3) The detection rate of coronary flow by pulsed Doppler of the two methods: LMT; 66.8/0%, LAD; 70.0/31.8%, LCx; 6.6/0%. RCA; 26.7/0%. 4) Coronary flow was detected by transesophageal two-dimensional Doppler in 73.3% of LMT, 76.6% of LAD, 6.6% LCx and 43.3% of RCA. 5) RCA flow was not detected by transesophageal two-dimensional Doppler in two patients who had complete obstruction of the proximal RCA although RCA near the orifice was obviously imaged by two-dimensional echocardiography. In conclusion, TED had an advantage over TTD in detecting coronary arteries and their blood flow, but TTD had an advantage over TED as to the visible length of coronary artery. When RCA near the orifice was clearly visualized, the absence of RCA flow by TED implied complete obstruction of the proximal RCA.

Arteries↗
PubMed1990

Isolation and characterization of three positional isomers of diglucosylcyclomaltoheptaose.

Three positional isomers of diglucosylcyclomaltoheptaose [(G)2-beta-cyclodextrin], 6(1),6(4)-di-O-(a-D-glucopyranosyl)-cyclomaltoheptaose (1), 6(1),6(3)-di-O-(a-D-glucopyranosyl)-cyclomaltoheptaose (2), and 6(1),6(2)-di-O-(a-D-glucopyranosyl)-cyclomaltoheptaose (3) were isolated by h.p.l.c. on a reversed-phase column from the mother liquors of a large-scale preparation of beta CD with Bacillus ohbensis cyclomaltodextrin glucanotransferase (EC 2.4.1.19) and were characterized by h.p.l.c. analysis of partial hydrolyzates and by 13C-n.m.r. spectroscopy. Their molecular weights were confirmed by f.a.b.-m.s. Their characteristic chromatographic behavior on four h.p.l.c. columns of different separation modes was found to be very useful for their identification. It is particularly noteworthy that the first application of a graphitized carbon column to CDs enabled a fine separation of all three positional isomers.

Carbohydrate Sequence↗
PubMed1990

Purification and properties of aldose reductase and aldehyde reductase from EHS tumor cells.

Engelbreth-Holm-Swarm (EHS) tumor cells were utilized as a model for investigating the production of basement membrane components. These cells contain two immunologically distinct NADPH-dependent reductases, aldose reductase (EC 1.1.1.21) and aldehyde reductase (EC 1.1.1.2), which were purified to apparent homogeneity by a combination of procedures which included ammonium sulfate fractionation, Sephadex G-75 gel filtration, Matrex Gel Orange A affinity chromatography, and chromatofocusing on Pharmacia Mono P. The molecular weights of aldose and aldehyde reductases were estimated to be 38K and 40K, respectively, by sodium dodecyl sulfate-polyacrylamide gel electrophoresis. Substrate specificity studies showed that both enzymes were capable of reducing a variety of aldehydes to their respective alcohols; however, only aldehyde reductase oxidized L-gulonic acid. Surprisingly, both enzymes showed similar reactivities with D-glucose and D-galactose, suggesting that both aldose and aldehyde reductases may contribute to sorbitol production in the EHS tumor cell. The activities of both enzymes were increased by the presence of sulfate ion, but chloride ion decreased the activity of aldose reductase. Both aldose and aldehyde reductases were inhibited by a series of structurally diverse aldose reductase inhibitors.

Alcohol Dehydrogenase↗
PubMed1990

Characterization of aldose reductase and aldehyde reductase from the medulla of rat kidney.

Aldose reductase and aldehyde reductase from the medulla of the rat kidney have been purified to homogeneity by using affinity chromatography, gel filtration and chromatofocusing. The molecular weights of aldose reductase and aldehyde reductase by sodium dodecyl sulfate (SDS)-polyacrylamide gel electrophoresis were found to be 37000 and 39000, respectively. The isoelectric points of aldose reductase and aldehyde reductase were found to be 5.4 and 6.2 by chromatofocusing, respectively. The major differences of amino acid compositions between both enzymes were found in serine, alanine and aspartic acid. Substrate specificity studies showed that aldose reductase utilized aldo-sugars such as D-glucose and D-galactose, but aldehyde reductase did not use them. The Km values of aldose reductase for various substrates were lower than those of aldehyde reductase. Aldose reductase utilized both reduced nicotinamide adenine dinucleotide phosphate (NADPH) and reduced nicotinamide adenine dinucleotide (NADH) as coenzymes, whereas aldehyde reductase utilized only NADPH. The presence of the sulfate ion resulted in a dramatic activation of aldose reductase whereas it did not affect aldehyde reductase activity. These enzymes were strongly inhibited by the known aldose reductase inhibitors. However, aldose reductase was more susceptible than aldehyde reductase to inhibition by the aldose reductase inhibitors.

Aldehyde Oxidoreductases↗
PubMed1990

Optic nerve degeneration caused by supraophthalmic carotid artery infusion with cisplatin and ACNU. Case report.

A 28-year-old woman with a left frontoparietal anaplastic astrocytoma was treated postoperatively with a combination of cisplatin and 1-(4-amino-2-methylpyrimidine-5-yl) methyl-3-(2-chloroethyl)-3-nitrosourea hydrochloride (ACNU). The drugs were infused via the left supraophthalmic internal carotid artery in an attempt to avoid ocular toxicity. The patient subsequently developed blindness in the left eye and a right temporal hemianopsia from marked degeneration of the left optic nerve and tract. It is apparent that the placement of a catheter into the supraophthalmic carotid artery does not exclude visual complications.

Adult↗