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Biomedical subjects

M Kai

Publications and source records attributed to M Kai.

At least 181 records · Page 10Linked to original sources
PubMed1985

High-performance liquid chromatographic method for monitoring leupeptin in mouse serum and muscle by pre-column fluorescence derivatization with benzoin.

A high-performance liquid chromatographic method is described for the determination of leupeptin, a possible therapeutic drug for muscular dystrophy, in mouse serum and muscle. Leupeptin is reduced with sodium borohydride to leupeptinol, and then converted to a fluorescent derivative with benzoin. The derivative is separated on a reversed-phase column (LiChrosorb RP-18) with isocratic elution and determined with fluorescence detection. The detection limits of leupeptin in serum and muscle are 250 pmol/ml (107 ng/ml) and 500 pmol/g (214 ng/g), respectively, corresponding to approximately 150 fmol each in a 100-microliters injection volume. This method is simple and sensitive enough to permit the quantification of leupeptin in biological samples from mice dosed with leupeptin.

Animals↗
PubMed1985

Determination of p-hydroxybestatin in human serum by high-performance liquid chromatography using fluorescence detection.

A high-performance liquid chromatographic method is described for the fluorimetric determination of p-hydroxybestatin (an active metabolite of bestatin) in human serum. p-Hydroxybestatin is formylated in an alkaline medium in the presence of chloroform, and converted to a fluorescent derivative with 1,2-diamino-4,5-dimethoxybenzene. This derivative is then separated on a reversed-phase column (TSK gel ODS-120T) with isocratic elution. The detection limit of p-hydroxybestatin in serum is 15 ng (46 pmol) per ml serum (115 pg in a 100-microliters injection volume). This method is simple and sensitive enough to determine p-hydroxybestatin in serum (200 microliters) from muscular dystrophic patients and from healthy subjects dosed with bestatin.

Chemical Phenomena↗
PubMed1984

High-performance liquid chromatographic measurement of guanidino compounds of clinical importance in human urine and serum by pre-column fluorescence derivatization using benzoin.

High-performance liquid chromatographic microanalyses for guanidino compounds in human physiological fluids have been accomplished by means of a pre-column fluorescence derivatization method using benzoin. The guanidino compounds in urine or deproteinized serum after ultrafiltration are converted to the fluorescent derivatives with benzoin in an alkaline medium, and the derivatives are separated simultaneously within 25 min on a reversed-phase column (mu Bondapak Phenyl) with a linear gradient elution of methanol in aqueous mobile phase (pH 8.5). The method permits the quantitative determination of guanidinosuccinic acid, methylguanidine, taurocyamine and guanidinobutyric acid at concentrations of as low as 8-78 pmol/ml in human urine and serum.

Adult↗
PubMed1984

Measurement of enkephalin peptides in canine brain regions, teeth, and cerebrospinal fluid with high-performance liquid chromatography and mass spectrometry.

Endogenous enkephalin pentapeptides are measured with unambiguous molecular specificity in canine and human tissue and fluid extracts. Both field desorption and fast atom bombardment mass spectrometry have been used to produce a protonated molecular ion of the peptide high-performance liquid chromatography fraction. The protonated molecular ion is subjected to collision-activated dissociation processes and a linked-field scan (B/E) selects a unique amino acid sequence-determining ion for monitoring and measurement. Stable isotope-incorporated peptide internal standards are used for quantification. Endogenous enkephalins are measured in hypothalamus, cerebrospinal fluid, pituitary, caudate nucleus, and tooth pulp extracts. Part-per-billion levels of endogenous peptide are measured.

Animals↗
PubMed1984

High-performance liquid chromatographic analyser for guanidino compounds using benzoin as a fluorogenic reagent.

An automatic analyser based on high-performance liquid chromatography has been developed for the quantification of biogenic guanidino compounds in human physiological fluids. Fourteen guanidino compounds are mutually separated within 35 min on a cation-exchange column with a stepwise gradient elution of pH and/or ionic strength in the mobile phase and then converted automatically to their fluorescent derivatives with benzoin. The method in this system is simple, rapid and sensitive; the lower limits of detection are 5-50 pmol for monosubstituted guanidino compounds, 1 nmol for creatine and 20 nmol for creatinine in 100 microliter of injection volume.

Benzoin↗
PubMed1984

Determination of bestatin in serum by high-performance liquid chromatography with fluorescence detection.

A simple method for the determination of bestatin and its major metabolite in man, p-hydroxybestatin, in human serum was investigated; the method employs high-performance liquid chromatography with fluorescence detection. Bestatin and p-hydroxybestatin are oxidized to phenylacetaldehyde and p-hydroxyphenylacetaldehyde, respectively, with periodate, which are then converted into fluorescent compounds with 4,5-dimethoxy-1,2-diaminobenzene. The compounds are separated by reversed-phase chromatography on LiChrosorb RP-18. The detection limits of bestatin and p-hydroxybestatin are 0.2 and 0.4 microgram/ml serum, respectively. This method permits the precise determination of bestatin in serum (20 microliter) from patients administered bestatin. p-Hydroxybestatin in serum can not be measured by this method because of its low concentration (less than the detection limit).

Chromatography, High Pressure Liquid↗