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Biomedical subjects

J Kawakami

Publications and source records attributed to J Kawakami.

48 records · Page 3Linked to original sources
PubMed1992

Pharmacokinetic profile of glycyrrhizin in healthy volunteers by a new high-performance liquid chromatographic method.

An improved high-performance liquid chromatographic method was developed for the quantification of glycyrrhizin and its metabolites in human plasma. The improved method was selective and made it possible to determine precisely glycyrrhizin at levels as low as 500 ng/mL. The pharmacokinetic behavior of glycyrrhizin and its metabolites after oral and intravenous administration of glycyrrhizin to normal subjects was investigated. After oral administration of glycyrrhizin (100 mg) to three normal subjects, the major metabolite of glycyrrhizin (glycyrrhetic acid) appeared in plasma (less than 200 ng/mL), but glycyrrhizin was not found. On the other hand, glycyrrhizin was found in urine, and the amount excreted was 1.1-2.5% of the dose. This finding suggests that glycyrrhizin is partly absorbed in the intact form from the gastrointestinal tract. The concentration of glycyrrhizin in plasma after intravenous administration of glycyrrhizin (40, 80, and 120 mg) showed biexponential profiles during the 24-h period after administration of each dose. The glycyrrhizin metabolites, glycyrrhetic acid and glycyrrhetic acid-3-O-glucuronide, were not detected in either plasma or urine. The terminal half-life of glycyrrhizin, the apparent volume of the central compartment, the steady-state distribution volume, and the total body clearance in three dosing experiments were 2.7-4.8 h, 37-64 mL/kg, 59-98 mL/kg, and 16-25 mL/kg/h, respectively. Glycyrrhizin was not detected in plasma after oral administration of the usual therapeutic dose of glycyrrhizin, and no dose dependency of the drug was observed in the dose range of 40-120 mg.

Administration, Oral↗
PubMed1992

Identification of important bases for the self-cleavage activity at two single-stranded regions of genomic HDV ribozyme.

In order to determine important bases at two single-stranded regions [SSrA (726-731 nt) and SSrB (762-766)] derived mainly from secondary structure models in genomic hepatitis delta virus (HDV) ribozyme possessing self-cleavage activity, we have constructed several point mutants at these two regions on the HDV88 molecule (683-770). Among the bases at SSrA and SSrB regions C763 was found to play an essential role during self-cleavage process since substitutions to any other bases viz. A or G or U completely abolished the activity.

Base Sequence↗
PubMed1991

Selective high-performance liquid chromatographic method for the determination of glycyrrhizin and glycyrrhetic acid-3-O-glucuronide in biological fluids: application of ion-pair extraction and fluorescence labelling agent.

A selective high-performance liquid chromatographic method has been developed for the simultaneous determination of glycyrrhizin and glycyrrhetic acid-3-O-glucuronide in biological fluids of the rat. The procedure is based on the ion-pair formation using tetra-n-amylammonium bromide, extraction with ethyl acetate-n-heptane from the salt-saturated aqueous phase, labelling with 4-bromomethyl-7-methoxycoumarin, followed by chromatographic separation with fluorescence detection. Glycyrrhizin in plasma, bile and urine could be precisely determined in concentrations as low as 1, 1 and 2.5 micrograms/ml, respectively, in a 0.1-ml sample. The equivalent values for the glucuronide were 1, 2.5 and 2.5 micrograms/ml, respectively. The method is applicable in pharmacokinetic studies of glycyrrhizin in small animals.

Animals↗
PubMed1987

The corneal endothelium in xeroderma pigmentosum.

The corneal endothelia of 8 xeroderma pigmentosum patients were evaluated by means of a specular microscope. All cases but 1 showed decreased cell density and all cases of this series showed an increased coefficient of variation in cell area, compared to that of normal persons. The regression analysis between the cell density and age revealed a close affinity to that of the normal aging process when the ultraviolet-survival lethal dose of each patient was taken into consideration. The loss of corneal endothelial cells in the xeroderma pigmentosum patients may be caused at an extraordinary high rate, in proportion to their clonogenic ultraviolet-survival rate.

Adolescent↗
PubMed1979

Uroporphyrinogen I synthase from human erythrocytes: separation, purification, and properties of isoenzymes.

Uroporphyrinogen I synthase [porphobilinogen ammonia-lyase (polymerizing), EC 4.3.1.8] from human erythrocytes was separated into two active protein peaks (A and B on DEAE-cellulose, by ammonium sulfate fractionation, on Sephadex G-100, and on DEAE-Sephadex A-50 with a NaCl gradient. The final purification was 613 and 743 times for A and B, respectively. The corresponding yields were 2.2 and 3.4% Fraction A was separated further into two (A1 and A2) active protein bands and fraction B into three (B1, B2, and B3) on analytical polyacrylamide disc gel electrophoresis. Bands A1 and A2 were identical with B1 and B2; B3 represented a third isoenzyme. Molecular weights (mean +/- SEM), measured by gel filtration and sodium dodecyl sulfate/polyacrylamide gel electrophoresis, were 38,000 +/- 1000 for B1 and 40,000 +/- 1000 for B2 and B3. Isoelectric focusing on 4% polyacrylamide gel separated both fractions A and B into three active protein bands. Maximal activity of the enzyme was found in gel cuts (5-mm) at pH 5.6 for both fractions A and B.

Ammonia-Lyases↗