Several aspects of vertical transmission of Moloney virus.
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Abortion, Spontaneous↗
Biomedical subjects
Y Ohba
Publications and source records attributed to Y Ohba.
Aminopyrazine analogues as chemiluminescence derivatization reagents for pyruvic acid.
Aminopyrazine analogues were studied as sensitive and selective chemiluminescence derivatization reagents for pyruvic acid. These analogues reacted with pyruvic acid under acidic conditions at 100 degrees C to produce Cypridina luciferin derivatives, which exhibit chemiluminescence by reaction with hydrogen peroxide in the presence of potassium t-butoxide in dimethylformamide. Of the four aminopyrazine analogues (2-amino-5-phenylpyrazine, 2-amino-5-(4-hydroxyphenyl)pyrazine, 2-amino-5-(3,4, 5-trimethoxyphenyl)pyrazine, and 2-aminoquinoxaline), in the present test 2-amino-5-(3,4,5-trimethoxyphenyl) pyrazine was the most sensitive for pyruvic acid, and the chemiluminescence intensity was about four times higher than that obtained with aminopyrazine.
Indicators and Reagents↗
Determination of urinary free cortisol by high performance liquid chromatography with sulphuric acid-ethanol derivatization and column switching.
A rapid and highly sensitive determination method for urinary free cortisol has been developed using reversed phase high performance liquid chromatography (HPLC) with a precolumn for sulphuric acid-ethanol fluorescence derivatization and column switching. Urinary cortisol, eluted from the octadecylsilane-bonded silica (ODS) minicolumn with 90% aqueous ethanol, was derivatized with the addition of sulphuric acid only at ambient temperature. Cortisol derivatives injected directly onto the ODS precolumn were purified on-line. After switching the columns, the cortisol derivative was separated on an ODS analytical column with a retention time of 15.3 min and monitored at an emission wavelength of 520 nm (exitation wavelength of 365 nm) to decrease the detection limit to 0.26 microgram/dL (signal-to-noise ratio = 3). The automated HPLC operation resulted in good reproducibility and recovery of the stable cortisol derivative at 5 degrees C.
Chromatography, High Pressure Liquid↗
Cardiohaemodynamic effects of long-term intravenous administration of N-(2-hydroxyethyl)nicotinamide nitrate (SG-75), a potent coronary vasodilator: comparison with glyceryl trinitrate.
1. Cardiohaemodynamic changes have been studied in beagle dogs treated with intravenous injections of either 300 micrograms/kg of N-(2-hydroxyethyl)nicotinamide nitrate (SG-75) or 30 micrograms/kg of glyceryl trinitrate three times a day for 1-2 months. Throughout the experimental period, no significant changes in general behaviour, body weights and plasma levels of enzymes and substrates were observed in either the SG-75-or glyceryl-trinitrate-treated groups. 2. At 1 and 2 months after the start of chronic drug administrations, the dogs were anaesthetized and measurements were made of resting systemic blood pressure, pulse pressure, heart rate, right atrial pressure, coronary blood flow, aortic blood flow, left ventricular (LV) pressure and LVdP/dt: there were no significant differences between non-treated dogs and dogs treated chronically with SG-75 or glyceryl trinitrate. 3. The effects of the acute intravenous administration of SG-75 and glyceryl trinitrate were examined in dogs pretreated intravenously with SG-75 (300 micrograms/kg) and glyceryl trinitrate (30 micrograms/kg), respectively, three times a day for 1-2 months. The depressor and coronary vasodilator responses to the two drugs remained unchanged in comparison with those in non-treated dogs. 4. These results indicated that, with the doses used, neigher SG-75 nor glyceryl trinitrate produced changes in sensitivity or tolerance after long-term intravenous administration.
Animals↗
Preference of human cdc2 kinase for peptide substrate.
Human cyclin B1-bound cdc2 kinase phosphorylated the threonine residue in the sequence -Thr-Pro-Lys-Lys-Ala- but hardly phosphorylated it in the sequence -Thr-Pro-Lys-Ala-Lys. The sequence -Thr-Pro-Ala-Pro-Lys-, as found in p53 protein, was also phosphorylated by this enzyme, but less efficiently than in the sequence described above. When the threonine residue in -Thr-Pro-Lys-Lys-Ala- was changed to a serine or a tyrosine residue, the enzyme phosphorylated the serine, but not the tyrosine residue. Changing the lysine next to the proline to alanine reduced its efficiency as a substrate. The peptide, Ala-Ala-Ala-Ala-Lys-Thr-Pro-Ala-Lys-Ala-Ala, containing the -Thr-Pro-Ala-Lys- sequence, but not the other lysine residues, was not used as a substrate by the kinase.
Amino Acid Sequence↗