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H Oe

Publications and source records attributed to H Oe.

At least 37 records · Page 2Linked to original sources
PubMed1991

The mode of vasorelaxing action of melatonin in rabbit aorta.

1. The vasorelaxing effect of melatonin on the contractile response to 5-hydroxytryptamine (5-HT) was investigated in rabbit isolated aorta. 2. Melatonin (10(-5)-10(-3) M) caused relaxation of the 5-HT (10 M) response in a concentration-dependent manner. Nifedipine (10(-6) M) did not affect the relaxing action of melatonin. 3. Pretreatment with methylene blue (10(-5) M) or nitroglycerin (3 x 10(-8) M) inhibited or potentiated, respectively, the relaxing action of melatonin. 4. Pretreatment with melatonin (10(-3) M) or M&B 22.948 (10(-3) M) potentiated the relaxing effect of nitroglycerin (10(-9)-10(-5) M) on the contraction induced by PGF2 alpha (4 x 10(-6) M). The effect of a combined treatment with melatonin and M&B 22.948 was not significantly different from that of a single treatment with M&B 22.948. 5. Melatonin (10(-5)-10(-3) M) inhibited the activity of cGMP-phosphodiesterase, in a concentration-dependent manner. 6. These results suggest that the vasorelaxing action of melatonin may be due to an increase in the level of cGMP.

3',5'-Cyclic-GMP Phosphodiesterases↗
PubMed1991

Vasorelaxing action of melatonin in rat isolated aorta; possible endothelium dependent relaxation.

1. Melatonin (10(-4)-10(-3) M) inhibited contractile response to 5-hydroxytryptamine (5-HT) and KCl in rat isolated aorta. 2. In the presence of verapamil but not nifedipine, melatonin failed to inhibit residual response to KCl. 3. In the aorta precontracted with 5-HT, PGF2 alpha, or KCl, melatonin (10(-6)-10(3) M) caused relaxation. Removal of endothelium only inhibited the melatonin relaxation on the 5-HT response. Methylene blue also inhibited the melatonin relaxation. 4. Nifedipine and verapamil partly inhibited the melatonin relaxation on the 5-HT response. In the absence of endothelium, verapamil but not nifedipine further inhibited the melatonin relaxation. 5. M & B 22,948 inhibited the melatonin relaxation. Melatonin potentiated the nitroglycerin relaxation. In the absence of endothelium, nitroglycerin and melatonin potentiated the relaxation by melatonin and nitroglycerin, respectively. 6. These results suggest that the mode of inhibitory action of melatonin is somewhat similar to that of verapamil. In addition, the vasorelaxing effect of melatonin on the 5-HT response is endothelium dependent and also may be related to the inhibition of cGMP metabolism.

3',5'-Cyclic-AMP Phosphodiesterases↗
PubMed1989

Effects of anion binding on the conformations of the two domains of ovotransferrin.

A previous paper (Harris (1985) Biochemistry 24, 7412-7418) reported the occurrence of two classes of anion binding sites in transferrin. To evaluate the locations of the two anion binding sites in relation to the two major domains of transferrin we determined the binding constants of whole ovotransferrin and its two half-molecules by means of the difference UV spectroscopic technique. Anions induced strong negative absorbance at 245 nm in the order: citrate greater than phosphate greater than bicarbonate for whole ovotransferrin and the N-terminal half-molecule; and: phosphate greater than citrate greater than bicarbonate for the C-terminal half-molecule. The anion dissociation constants of the N-terminal half-molecule were consistent with lower dissociation constants, and those of the C-terminal half-molecule, with higher dissociation constants of whole ovotransferrin, indicating that the two classes of anion binding sites correspond to the binding sites in individual structural domains. Anion binding markedly protected the N-terminal half-molecule, but not the C-terminal half-molecule from digestion with trypsin and disulfide reduction with dithiothreitol. As to the far and near ultraviolet CD spectra data, however, there was no significant difference between in the presence and absence of an anion. Therefore, the binding of an anion would induce some conformational changes which were not reflected by the CD spectrum.

Anions↗
PubMed1988

Analyses of intramolecular disulfide bonds in proteins by polyacrylamide gel electrophoresis following two-step alkylation.

A method that makes use of polyacrylamide gel electrophoresis was developed for the analysis of intramolecular disulfide bonds in proteins. Proteins with different numbers of cleaved disulfide bonds are alkylated with iodoacetic acid or iodoacetamide as the first step. The disulfide bonds remaining were reduced by excess dithiothreitol, and the newly generated free sulfhydryl groups were alkylated with the reagent not yet used (iodoacetamide, iodoacetic acid, or vinyl-pyridine) as the second step. This treatment made it possible for lysozyme (Mr, 14,000; 4 disulfides), the N-terminal half-molecule of conalbumin (Mr, 36,000; 6 disulfides), the C-terminal half-molecule of conalbumin (Mr, 40,000; 9 disulfides), and whole conalbumin (Mr, 78,000; 15 disulfides) to be separated by acid-urea polyacrylamide gel electrophoresis into distinct bands depending on the number of disulfide bonds cleaved. The method allowed us to determine the total number of disulfide bonds in native proteins and to assess the cleaved levels of disulfide bonds in partially reduced proteins. Two-step alkylation used in combination with radioautography was especially useful for the analysis of disulfide bonds in proteins synthesized in complex biological systems.

Alkylation↗
PubMed1988

Amino-terminal and carboxyl-terminal half-molecules of ovotransferrin: preparation by a novel procedure and their interactions.

The amino- (N-) and carboxyl- (C-)terminal half-molecules of ovotransferrin were prepared by a novel procedure. The trypsin-nicked ovotransferrin (Ikeda et al. (1985) FEBS Lett. 182, 305-309), in which the two half-molecules interact non-covalently forming a stable dimer, was purified by gel filtration and anion-exchange column chromatography. By subsequent cation-exchange chromatography, the nicked form was distinctly separated into an equivalent amount of the N-terminal and C-terminal half-molecules. Analyses of the N-terminal and C-terminal sequences indicated that the N-terminal and C-terminal half-molecules comprised the alignments of residues 1-332 and 342-686 of ovotransferrin, respectively. Anion-exchange chromatography, gel filtration chromatography, and non-denaturing polyacrylamide gel electrophoresis revealed that the isolated half-molecules had the ability to re-associate in solution. The contents of alpha-helix and beta-sheet of the two half-molecules, as determined by circular dichroism (CD) spectra, were very similar to those of intact ovotransferrin. No prominent alteration in the secondary structure of the two half-molecules was induced by the re-association.

Amino Acids↗
PubMed1983

Radioassay of the folate-hydrolyzing enzyme activity, and the distribution of the enzyme in biological cells and tissues.

A sensitive radioassay method has been developed to quantitate the activity of the folate-hydrolyzing enzyme which catalyzes the hydrolysis of folic acid to pteroic acid and glutamic acid. The method is based on analyzing [2-14C]pteroic acid separated by a thin-layer chromatography on an Avicel SF cellulose plate using 0.1 M potassium phosphate buffer, pH 7.0, as a solvent. This method was found to be more sensitive than a conventional photometric method to determine the activity of the folate-hydrolyzing enzyme. High activities of the enzyme were found in Crithidia fasciculata ATCC 12857, Neurospora crassa IFO 6979 and rat liver. Smaller activities of the enzyme were widely distributed in other microbial cells and mammalian tissues.

Animals↗
PubMed1981

A random controlled study of the prophylactic effect of lysozyme chloride on post-transfusion hepatitis.

In a study designed to determine the preventive effect of lysozyme on post-transfusion hepatitis, 260 patients with orthopedic diseases, who received blood by transfusion during a period of 5 years from June 1970 to May 1975, were divided at random into a group of 123 patients treated with lysozyme is doses of 60 to 170 mg/day for 4 to 24 weeks, and a control group of 137 patients. The incidence of post-transfusion hepatitis was 10 (8.1%) out of 123 patients for the treated group, and 28 (20.4%) out of 137 patients for the control group. Icteric hepatitis occurred in 1 (0.8%) patient in the treated group, while its incidence in the control group was 8 (5.8%) out of 137 patients.

Adult↗