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56. Interferon alpha therapy in hemodialysis patients with chronic hepatitis C.

Author

Iwata, Jiro, primary, Ohnishi, Takahiro, additional, Suga, Takaaki, additional, Hasegawa, You, additional, Nabeshima, Kazuo, additional, Hamada, Minoru, additional, Ueno, Toshimichi, additional, Ichikawa, Takehiko, additional, Mizutani, Yasuhide, additional, Fujimoto, Masao, additional, Murayama, Takashi, additional, Okuda, Yoshiro, additional, and Tameda, Yukihiko, additional

Published
1995
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61. Multiple Microhamartomas of the Biliary Tract System (Von Meyenburg Complexes) with Multiple Liver Cysts — Diagnostic Imaging and Laparoscopic Findings —

Author

TAMEDA, Yukihiko, primary, KOSAKA, Yoshitane, additional, SHIRAKI, Katsuya, additional, KIHIRA, Takayuki, additional, OHASHI, Yohei, additional, FUJIOKA, Hiromichi, additional, HAMADA, Minoru, additional, MIYAZAKI, Mitsukazu, additional, ITO, Nobuyasu, additional, TAKASE, Kojiro, additional, and NAKANO, Takeshi, additional

Published
1993
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63. Hepatitis in an Adult with Rubella.

Author

TAMEDA, Yukihiko, primary, KOSAKA, Yoshitane, additional, SHIRAKI, Katsuya, additional, OHASHI, Yohei, additional, HAMADA, Minoru, additional, MIYAZAKI, Mitsukazu, additional, ITO, Nobuyasu, additional, TAKASE, Koujiro, additional, and NAKANO, Takeshi, additional

Published
1993
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78. The Steady-State Kinetics of the Enzyme Reaction Tested by Site-Directed Mutagenesis of Hydrophobic Residues (Val, Leu, and Cys) in the C-Terminal α-Helix of Human Adenylate Kinase1.

Author

Ayabe, Takanori, Kyu Park, Seung, Takenaka, Hitoshi, Takenaka, Osamu, Maruyama, Hideharu, Sumida, Michihiro, Onitsuka, Toshio, and Hamada, Minoru

Subjects
RABIES, MUTAGENESIS, RADIOGENETICS, ADENYLATE cyclase, CATALYSIS
Abstract

To elucidate whether the C-terminal region in human adenylate kinase participates in the interaction with the substrate (MgATP2− and/or AMP2−), hydrophobic residues (Val-182, Vall86, Cysl87, Leul93, and Leul93) were substituted by site-directed mutagenesis and the steady-state kinetics of fifteen mutants were analyzed. A change in the hydro-phobic residues in the C-terminal domain affects the affinity for substrates (Km), that is, not only for MgATP2− but also for AMP2−, and the catalytic efficiency (kcat. The results obtained have led to the following conclusions: (i) Val182 may interact with both MgATP2− and AMP2− substrates, but to a greater extent with MgATP2−, and play a role in catalysis. (ii) Vall86 appears to play a functional role in catalysis by interacting with both MgATP2- and AMP2− to nearly the same extent, (iii) Cysl87 appears to play a functional role in catalysis, (iv) Leu 190 appears to interact with both MgATP2− and AMP2− substrates but to a greater extent with AMP2−, (v) Leul93 appears to interact with both MgATP2− and AMP2− but to a greater extent with AMP2−. The activity of all mutants decreased due to the change in substrate-affinity. The closer the residue is located to the C-terminal end, the more its mutation affects not only MgATP2− but also AMP2− substrate binding. The hydrophobic alterations disrupt hydrophobic interactions with substrates and that might destabilize the conformation of the active site. The more C-terminal part of the α-helixappears to interact with AMP, as if it has swung out and rotated to cover the adenine moieties. The C-terminal α-helix of human adenylate kinase appears to be essential for the interaction with adenine substrates by swinging out during catalysis. [ABSTRACT FROM AUTHOR]

Published
2000
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87. Effect of prolonged hypothermic ischaemia on myocardial sarcoplasmic reticular calcium transport.

Author

Fukumoto, Kohji, Takenaka, Hitoshi, Koga, Yasunori, and Hamada, Minoru

Abstract

Study objective – The aim of the study was to assess the effects of hypothermia on sarcoplasmic reticulum in myocardium subjected to prolonged ischaemia.Design – Calcium regulatory activity of myocardial sarcoplasmic reticulum was measured in hearts subjected to various periods of hypothermic ischaemia in comparison with hearts subjected to normothermic ischaemia.Subjects – Hearts (n = 5-9 per experiment) were obtained from male New Zealand white rabbits, 2.0-2.8 kg weight.Measurements and results – Calcium uptake and calcium dependent ATPase activity were measured in isolated sarcoplasmic reticulum vesicles after hypothermic ischaemia was produced by immersing hearts in saline at 4°C for 3,6, or 12 h. Normothermic hearts were immersed for 3 h at 37°C. Calcium uptake and calcium dependent ATPase (Ca-ATPase) activity were markedly inhibited by normothermic ischaemia. In hypothermic ischaemia, calcium uptake was only slightly depressed after 3 h, though longer periods of ischaemia resulted in significant depression of uptake. Ca-ATPase activity was unaffected after 6 h of hypothermic ischaemia. The ratio of calcium uptake to Ca-ATPase activity decreased after 3 h of hypotheric ischaemia. The phosphoenzyme concentration in sarcoplasmic reticulum was unaffected up to 6 h. The ratio of Ca-ATPase activity to phosphoenzyme concentration was not significantly altered until 12 h. Protein composition, examined by SDS-polyacrylamide gel electrophoresis, showed a decrease in 100 000 dalton polypeptide in normothermic ischaemia and after 12 h of hypothermic ischaemia.Conclusions – These results suggest that the depression of calcium uptake activity after 6 h of hypothermic ischaemia is likely to be due to uncoupling of calcium transport from ATP hydrolysis. Depressed Ca-ATPase activity at 12 h can be attributed to a reduction in the number of active calcium pump units. Hypothermia preserves function of myocardial sarcoplasmic reticulum during ischaemia for up to 3 h. [ABSTRACT FROM PUBLISHER]

Published
1990

89. RADIOPHOTOLUMINESCENCE DOSIMETRY USING A SMALL SPHERICAL GLASS: A PRELIMINARY PHANTOM STUDY.

Author

Nakagawa, Keiichi, Yoda, Kiyoshi, Shiraki, Takashi, Sasaki, Katsutake, Miyazawa, Masanori, Ishidoya, Tatsuyo, Ohtomo, Kuni, and Hamada, Minoru

Subjects
DOSIMETERS, RADIATION dosimetry, PHOTOLUMINESCENCE, PHOSPHATES, RADIOACTIVITY measurements, IONIZING radiation dosage, IMAGING phantoms, LUMINESCENCE, ABSORPTION
Abstract

A radiophotoluminescence dosimetry has been proposed using a spherical silver-activated phosphate glass with a diameter of 1.5 mm. A 6 MV photon dose of 2 Sv (2 Gy) was delivered to 14 spherical glass samples placed between two solid water phantoms at a depth of 10 cm. The samples were positioned within a 20 × 20 mm2 centred at beam axis to ensure uniform dose absorption. A normalised output from a read-out system was obtained by simultaneously measuring luminescence from a non-irradiated reference and that from an irradiated reference to eliminate background contamination and time-varying fluctuation of the readout system, leading to a normalised standard deviation of 1.8%. A dose up to 3.5 Sv (3.5 Gy) was delivered to three spherical glass samples positioned between two solid water phantoms at a depth of 10 cm. The normalised output increased linearly with the applied dose. [ABSTRACT FROM AUTHOR]

Published
2007
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90. Properties and Subunit Composition of the Pig Heart 2-Oxoglutarate Dehydrogenase

Author

Koike, Kichiko, Hamada, Minoru, Tanaka, Nobuyuki, Otsuka, Kin-Ichi, Ogasahara, Kyoko, and Koike, Masahiko

Abstract

The 2-oxoglutarate dehydrogenase, one of the component enzymes of the 2-oxoglutarate dehydrogenase complex, has been highly purified. The enzyme has a sedimentation coefficient (s020,w) of 10.3 S and diffusion coefficient (D020,w) of 3.92 x10-7cm2s-1. The weight average molecular weight was estimated to be about 216,000 from the sedimentation equilibrium data. The content of right-handed α helix in the enzyme molecule was estimated to be about 34% by both optical rotatory dispersion and circular dichroism. The enzyme was found to contain 1 molecule of protein-bound thiamine-PP per mole; some other kinetic and protein chemical properties are also reported.

Published
1974
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91. Mammalian α-Keto Acid Dehydrogenase Complexes

Author

Sakurai, Yukihiko, Fukuyoshi, Yukiko, Hamada, Minoru, Hayakawa, Taro, and Koike, Masahiko

Abstract

Lipoamide dehydrogenase (reduced nicotinamide adenine dinucleotide:lipoamide oxidoreductase, EC 1.6.4.3) has been isolated from the pig heart 2-oxoglutarate dehydrogenase complex, the pig heart pyruvate dehydrogenase complex, and a pig heart extract which was devoid of the two complexes. Two major molecular forms, designated as Fp-I and Fp-II in order of increasing anodic mobility, were detected in both electrophoretic patterns and triethylaminoethyl-cellulose column chromatograms of these three flavoprotein preparations. Fp-I is the main flavoprotein component of the 2-oxoglutarate dehydrogenase complex, and Fp-II is the main flavoprotein component of the pyruvate dehydrogenase complex. The uncomplexed form of lipoamide dehydrogenase appears to be a mixture of Fp-I and Fp-II. Ultracentrifugal analyses, absorption spectra, flavin contents, amino acid analyses, end group analyses, peptide mapping, and immunological experiments showed no significant differences between the two forms (Fp-I and Fp-II) of lipoamide dehydrogenase, thereby suggesting the identity of these two molecular forms of the enzyme. Comparison of enzymic activities, thiol contents, electrophoretic patterns after incubation with NADH and arsenite, and optical rotatory dispersion and circular dichroism spectra of the two forms suggests that these multiple forms may result from conformational differences around the active site, involving thiol groups and FAD. The two forms of lipoamide dehydrogenase are interchangeable with respect to both their function and ability to form the complexes; however, the enzymic, electrophoretic, and circular dichroism properties of OGDC-Fp-I were altered with respect to those of PDC-Fp-II when bound to the specific binding site in lipoate acetyltransferase molecule.

Published
1970
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92. Mammalian α-Keto Acid Dehydrogenase Complexes

Author

Tanaka, Nobuyuki, Koike, Kichiko, Otsuka, Kin Ichi, Hamada, Minoru, Ogasahara, Kyoko, and Koike, Masahiko

Abstract

Lipoate succinyltransferase (succinyl-CoA: dihydrolipoate S-succinyltransferase), a core enzyme of the 2-oxoglutarate dehydrogenase complex, has been highly purified. The enzyme has a sedimentation coefficient (s020,w) of 16.4 S and a diffusion coefficient (D020,w) of 1.65 x10-7cm2s-1. An average molecular weight was estimated to be about 1,000,000 from the sedimentation equilibrium data. The content of right-handed α helix in the enzyme molecule was estimated to be about 23% by optical rotatory dispersion and about 22% from circular dichroism spectra. The enzyme was found to contain 8 molecules of protein-bound lipoic acid per mole of enzyme; some other properties are also reported.

Published
1974
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93. Mammalian α-Keto Acid Dehydrogenase Complexes

Author

Tanaka, Nobuyuki, Koike, Kichiko, Hamada, Minoru, Otsuka, Kin-Ichi, Suematsu, Tadashi, and Koike, Masahiko

Abstract

The nonionic detergent Triton X-100 has been found to solubilize readily the pig heart 2-oxoglutarate dehydrogenase complex from the protamine precipitate eluate. A highly active preparation was obtained from the Triton X-100 extract by calcium phosphate gel-cellulose column chromatography.

Published
1972
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