Simultaneous determination of N-acetylaspartic acid, N-acetylglutamic acid, and N-acetylaspartylglutamic acid in whole brain of 3-mercaptopropionic acid-treated rats using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

The measurement of N-acetylaspartic acid (NAA), N-acetylglutamic acid (NAG), and N-acetylaspartylglutamic acid (NAAG) in the whole brain of 3-mercaptopropionic acid (3-MPA)-treated rats has been developed using liquid chromatography-mass spectrometry with an atmospheric pressure ionization interface system. The recoveries of these compounds were 90.85 +/- 3.43% for NAA, 91.62 +/- 5.47% for NAG, and 92.29 +/- 4.44% for NAAG. The detection limits for NAA, NAG, and NAAG were 12, 15, and 20 microg/ml, respectively. After administration of 3-MPA, the concentrations of NAA, NAG, and NAAG in the whole brain over 10 min increased 177.25, 134.23, and 127.70%, respectively. These concentrations then decreased over the next 60 min. The simultaneous determination of NAA, NAG, and NAAG using this method was found to be very useful for studies of metabolism of NAA, NAG, and NAAG in biological samples.

Simultaneous determination of gamma-aminobutyric acid and glutamic acid in the brain of 3-mercaptopropionic acid-treated rats using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

The measurement of gamma-aminobutyric acid (GABA) and glutamic acid (Glu) in the whole brain and in various regions of the brain in 3-mercaptopropionic acid (3-MPA)-treated rats has been developed using liquid chromatography-mass spectrometry with an atmospheric pressure ionization interface system. The recoveries of these compounds were 94.90+/-4.18% for GABA, 95.60+/-2.86% for Glu after ion-exchange treatment. The detection limits for GABA and Glu were 2.5+/-0.3 microg/ml and 5.0+/-0.8 microg/ml, respectively, when 20 microl sample were injected. GABA concentration in the whole brain decreased gradually to 5 min and reached 63% of normal value after administration of 3-MPA, and the concentration increased gradually thereafter until 60 min. Conversely, the concentration of Glu in the whole brain increased gradually to 10 min and reached 154% of normal value, and after that decreased gradually and reached almost normal level at 60 min after administration of 3-MPA. GABA concentration in various regions of brain decreased to 5 min in all regions after administration of 3-MPA, and reached normal levels at 60 min as in the whole brain. This method was found to be useful for studies of metabolism of GABA and Glu in biological samples.

Simultaneous determination of creatinine, creatine, and guanidinoacetic acid in human serum and urine using liquid chromatography-atmospheric pressure chemical ionization mass spectrometry.

A rapid and direct method for simultaneous determination of creatinine, creatine, and guanidinoacetic acid in biological samples has been developed by using column liquid chromatography-mass spectrometry (LC/APCI-MS). The determinations of creatinine, creatine, and guanidinoacetic acid in the samples of human urine and serum were carried out by scanning the [M + H]+ ions of each compound. The recoveries of authentic compounds were 93.87 +/- 6.00% (n = 5) for creatinine, 94.80 +/- 8.93% (n = 5) for creatine, and 90. 92 +/- 7.96% (n = 5) for guanidinoacetic acid after ion-exchange resin treatment. The content of creatinine in human urine and serum was also measured by the Jaffé method, a common method of determination of creatinine currently used in hospitals. The contents of creatinine, creatine, and guanidinoacetic acid obtained using LC/APCI-MS coincided well with those reported in previous papers.

Simultaneous determination of urinary cystathionine, lanthionine, S-(2-aminoethyl)-L-cysteine and their cyclic compounds using liquid chromatography-mass spectrometry with atmospheric pressure chemical ionization.

A measurement system for cystathionine (Cysta) lanthionine (LT), and S-(2-aminoethyl)-L-cysteine (AEC), and reduced products of their ketimines, perhydro-1,4-thiazepine-3,5-dicarboxylic acid (PHTZDC), 1,4-thiomorpholine-3,5-dicarboxylic acid (TMDA) and 1,4-thiomorpholine-3-carboxylic acid (TMA) in the urine samples of a patient with cystathioninuria and normal human subjects has been developed, using column liquid chromatography-mass spectrometry. The recoveries were about 90-105% for Cysta, LT and AEC, and about 77-87% for PHTZDC, TMDA and TMA after ion-exchange treatment. The concentrations of Cysta and PHTZDC in the urine of a patient with cystathioninuria were much higher compared with those in the urine of normal human subjects. The concentrations of AEC and TMDA were almost the same. LT and TMA could not be detected in the urine samples by this method. This method proved useful for the determination of sulfur-containing amino acids and their cyclic compounds in biological samples.

Characteristics of partially purified prolidase and prolinase from the human prostate.

Both prolidase and prolinase from the human prostate were separated into two peaks by TSK DEAE-5PW chromatography. These peaks of prolidase isozymes I and II differed from each other in their responses to preincubation with Mn2+, their substrate specificity, optimal pH, and heat stability. The molecular weights of prolidases I and II were estimated to be 110,000 and 165,000, respectively, by gel filtration. Substrate specificity of prolinase peaks I and II was almost the same, but they differed in optimal pH and heat stability. The molecular weights of prolinases I and II were about 85,000 and 63,000, respectively. These results indicate that two isozymes of prolidase and of prolinase, which differ in various characteristics, are present in the human prostate.

[Augmentation of resistance against metastatic tumor cells after local administration of PSK].

Local administration of PSK augmented the generation of cytotoxic lymphocytes and the induction of resistance against metastatic tumor. Augmented generation of cytotoxic lymphocytes may be ascribed to local effects of PSK in the lymph nodes, since this is mediated by Lyt-1+2+ cells. Local administration of PSK increased the threshold number of metastatic tumors eliminated by hosts. This finding seems to be important in relation to augmentation of resistance against metastasis or local implantation with a limited number of tumor cells.