Biomedical subjects

Takeshi Fukushima

Publications and source records attributed to Takeshi Fukushima.

At least 19 recordsLinked to original sources

PubMed2006

Hair analysis of histamine and several metabolites in C3H/HeNCrj mice by ultra performance liquid chromatography with electrospray ionization time-of-flight mass spectrometry (UPLC-ESI-TOF-MS): influence of hair cycle and age.

BACKGROUND: According to a previous study, the concentration of HA in the hair of SD rats was similar in each rat and the variation in HA concentration was not so great. However, the concentration in human hair was fairly different in each person. As possible reasons for the higher variation in human hair, the differences in hair cycles and age in each person may be considerable. Based on this idea, the studies using C3H/HeNCrj mice who can synchronize their hair cycle were performed for resolution of the influence of hair cycle and age. METHODS: The effects of hair cycle and age on the concentration of histamine (HA) and several metabolites, i.e., 1-methylhistamine (MHA), imidazole-4-acetic acid (IAA), and 1-methyl-4-imidazole-acetic acid (MIAA), in C3H/HeNCrj mice hair were investigated by ultra-performance liquid chromatography (UPLC) with electrospray ionization time-of-flight mass spectrometry (ESI-TOF-MS). HA and the metabolites were labeled with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) and 4-(N,N-dimethylaminosulfonyl)-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ). The resulting derivatives were separated by UPLC and determined with ESI-TOF-MS. RESULTS: A good linearity was achieved from the calibration curves, obtained by plotting the peak area ratios of the analytes relative to the internal standard (IS), i.e., histamine-alpha,alpha,beta,beta-d4 (HA-d4) or 4-imidazolecarboxylic acid (ICA), against the injected amounts of each compound. The detection limits of HA, MHA, IAA, and MIAA on mass chromatograms were 0.21, 1.0, 0.17, and 0.11 pmol, respectively. The concentrations of HA and the metabolites in the hair shafts and hair root of C3H/HeNCrj mice were determined by this method. The concentration of HA in the hair shaft was relatively higher in the telogen phase. In contrast, the HA content in the anagen phase was increased only in the hair root of old mice. CONCLUSION: HA appears to possess some effect on hair growth, although the exact reason was not obvious. The HA metabolites, i.e., MHA, MIAA and IAA, were also determined the same as HA; however, the difference in the metabolite concentrations between the hair cycle and age was not clear in both hair shaft and hair root. Such studies of the effect of hair cycle and age on these concentrations are the first report. This analytical technique may be applicable to the determination of various biological compounds in hair.

Age Factors↗

PubMed2006

Determination of kynurenic acid in human serum and its correlation with the concentration of certain amino acids.

BACKGROUND: Kynurenic acid (KYNA)--a tryptophan metabolite--elicits antagonistic activity against glutaminergic and cholinergic receptors; it has been suggested to have some relationship with neurological disorders. Considering this, serum KYNA may be an important marker in clinical diagnosis. We determined serum KYNA concentration and elucidate its correlation with several amino acids in human serum. METHODS: KYNA and amino acids concentrations in human serum of healthy subjects [n=35 (21 males and 14 females)] were determined by HPLC with fluorescence detection; thus, the correlation between KYNA concentration and that of several amino acids was examined in these subjects. RESULTS: Of the amino acids examined in this study, a significant negative correlation was observed between KYNA and glutamine (Gln) concentrations (r=-0.452, p<0.01) in the healthy subjects, particularly males (r=-0.687, p<0.01), and age-related changes were not observed. In addition to Gln, Gly and Ala concentrations showed a significant negative correlation with KYNA concentration in the serum of male subjects (r=-0.440 and -0.456, respectively, p<0.05). CONCLUSION: The significant correlation between KYNA and Gln concentrations in vivo may support the previous finding that kynurenine aminotransferase I (KAT I), responsible for the biosynthesis of KYNA, was identical to Gln transaminase K (GTK), which catalyses the transamination of Gln to 2-oxoglutamic acid. Both KYNA and Gln concentrations in vivo might be influenced due to altered KAT I/GTK activity.

Adolescent↗

PubMed2006

Rapid determination of histamine and its metabolites in mice hair by ultra-performance liquid chromatography with time-of-flight mass spectrometry.

The rapid determination of histamine (HA) and several metabolites, i.e., 1-methylhistamine (MHA), imidazole-4-acetic acid (IAA), and 1-methyl-4-imidazole-acetic acid (MIAA), in mice hairs was performed by ultra-performance liquid chromatography with time-of-flight mass spectrometry (UPLC-TOF-MS). HA and MHA, having a primary amino group (NH(2)) in their structures, were first labeled with 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) at 60 degrees C for 45 min in the mixture of 0.1M borax (pH 9.3) and acetonitrile (CH(3)CN). On the other hand, 4-(N,N-dimethylaminosulfonyl)-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ) was used for the labeling of a carboxylic acid group (COOH) in IAA and MIAA in the presence of 2,2'-dipyridyl disulfide (DPDS) and triphenylphosphine (TPP). The reaction with DBD-PZ was completed at 50 degrees C after 2h. The resulting derivatives of HA and the metabolites were perfectly separated using an ACQUITY UPLCtrade mark BEH C(18) column (1.7 microm, 100 x 2.1mm, i.d.) with the mixture of 20 mM HCOONH(4) and CH(3)CN (8:2). The structures of HA and the metabolites were identified from the protonated-molecular ions [M+H](+) and the de-protonated-molecular ions [M-H](-) of authentic compounds, obtained from TOF-MS measurement. A good linearity was achieved from the calibration curves, obtained by plotting the peak area ratios of the analytes relative to the internal standard (IS), i.e., histamine-alpha,alpha,beta,beta-d(4) (HA-d(4)) or 4-imidazolecarboxylic acid (ICA), against the injected amounts of each compound (1.0-25 pmol, r(2)=0.998). The detection limits of HA and the metabolites were less than 1 pmol. The proposed method was applied to the determination in the hair shafts of C3H mice. The average concentrations of HA, MHA, IAA and MIAA in 1mg of the hair shafts were 16.3 pmol (n=7), 21.6 pmol (n=3), 6.6 pmol (n=3) and 7.1 pmol (n=3), respectively. Because the proposed method provides good mass accuracy and the trace detection of HA and several metabolites in hair, this analytical technique seems to be applicable for the determination of various biological compounds in hair.

Animals↗

PubMed2006

Synthesis of the isotope-labeled derivatization reagent for carboxylic acids, 7-(N,N-dimethylaminosulfonyl)-4-(aminoethyl)piperazino-2,1,3-benzoxadiazole (d6) [DBD-PZ-NH2 (D)], and its application to the quantification and the determination of relative amount of fatty acids in rat plasma samples by high-performance liquid chromatography/mass spectrometry.

The isotope-labeled benzofurazan derivatization reagent for carboxylic acids, 7-(N,N-dimethylaminosulfonyl)-4-(aminoethyl)piperazino-2,1,3-benzoxadiazole (d6) [DBD-PZ-NH2 (D)] was synthesized. DBD-PZ-NH2 (D) was used for the accurate quantification of fatty acids by liquid chromatography/mass spectrometry (LC/MS). The standard fatty acids were derivatized with DBD-PZ-NH2 (D) to the stable isotope-labeled compounds for the fatty acids derivatives of DBD-PZ-NH2 and used for the internal standards. The obtained calibration curves for fatty acids were linear over the range 0.1-200 microM (r2 > 0.999). Fatty acids in plasma samples were determined after derivatization with DBD-PZ-NH2 and analyzed by LC/MS using standard fatty acid DBD-PZ-NH2 (D) derivatives as internal standards. Furthermore, the relative amounts of fatty acids in two plasma samples were determined after derivatization with DBD-PZ-NH2 and DBD-PZ-NH2) (D). The isotope-labeled derivatization reagent was useful for accurate quantification and the determination of relative amounts of the metabolites in biological samples having the target functional group.

Animals↗

PubMed2006

A further study on the combined use of internal standard and isotope-labeled derivatization reagent for expansion of linear dynamic ranges in liquid chromatography-electrospray mass spectrometry.

The combined use of a so-called internal standard and the isotope-labeled derivatization reagent for the quantification of analytes for liquid chromatography-mass spectrometry (LC/MS) was further studied. The sample solution (containing the analytes and an internal standard) was derivatized with the light form of the derivatization reagent, 7-(N,N-dimethylaminosulfonyl)-4-(aminoethyl)piperazino-2,1,3-benzoxadiazole (DBD-PZ-NH(2)) or 7-(N,N-dimethylaminosulfonyl)-4-piperazino-2,1,3-benzoxadiazole (DBD-PZ). A standard solution of the analytes (containing an internal standard) was derivatized with the isotope (d(6))-labeled derivatization reagent, DBD-PZ-NH(2) (D) or DBD-PZ (D), and served as the isotope-labeled internal standards. The peak heights of the targeted analytes derivatives in the sample solution were corrected using those of the internal standard and the heavy form derivatives of the standards, and the calibration curves were constructed. The curve bending of the calibration curves caused by the ion suppression at the ion source was suppressed and the linear dynamic ranges of the calibration curves were expanded. The derivatives of DBD-PZ-NH(2) were about 10 times more sensitively detected than those of DBD-PZ derivatives and, therefore, DBD-PZ-NH(2) might be suitable for sensitive detection.

Chromatography, Liquid↗

PubMed2006

Steroidal glycosides from the underground parts of Solanum sodomaeum.

A new steroidal glycoside has been isolated from the underground parts of Solanum sodomaeum L., along with seven known steroidal glycosides. Their chemical structures were determined on the basis of spectroscopic data and chemical evidence, and the structure of one known pregnane type glycoside was corrected. In addition, their antiproliferative activity against human promyelocytic leukemia (HL-60) cells was investigated, and five compounds exhibited stronger activity than cisplatin.

Antineoplastic Agents, Phytogenic↗

PubMed2005

Resolution of N-linked oligosaccharides in glycoproteins based upon transglycosylation reaction by CE-TOF-MS.

The resolution of asparagine-type oligosaccharides in glycoproteins was carried out by combination of the transglycosylation reaction and CE-TOF-MS. The oligosaccharides enzymatically transferred to a fluorescent acceptor (NDA-Asn-GlcNAc) with Endo-M. The resulting fluorescent-oligosaccharides were separated by CE and detected by TOF-MS. Disialo-Asn was successfully identified by the proposed procedure. Application to oligosaccharides in ovalbumin was also described in this communication.

Acetylglucosamine↗

PubMed2005

Synthesis of fluorescent label, DBD-beta-proline, and the resolution efficiency for chiral amines by reversed-phase chromatography.

DBD-d(and l)-beta-proline, new fluorescent chiral derivatization reagents, were synthesized from the reaction of 4-(N,N-dimethylaminosulfonyl)-7- fl uoro-2,1,3-benzoxadiazole (DBD-F) with beta-proline. The racemic mixture synthesized was separated by a chiral stationary phase (CSP) column, Chiralpak AD-H, with n-hexane-EtOH-TFA-diethylamine (70:30:0.1:0.1) as the mobile phase. The dl-forms were decided according to the results obtained from a circular dichroism (CD) detector after separation by the CSP column. The fractionated enantiomers reacted with chiral amine to produce a couple of diastereomers. The labeling proceeded in the presence of 1-ethyl-3-(3-dimethylaminopropyl)carbodiimide (EDC) and pyridine as the activation reagents. The reaction conditions were mild and no racemization occurred during the diastereomer formation. The resulting diastereomers fluoresced at around 570 nm (excitation at around 460 nm). Good linearity of the calibration curves was obtained in the range 1-75 pmol and the detection limits on chromatogram were less than 1 pmol. The separability of the diastereomers was compared with the diastereomers derived from DBD-d(or l)-proline. The resolution values (Rs) obtained from the diastereomers of three chiral amines with DBD-d(or l)-beta-proline were higher than those derived from DBD-d(or l)-proline, e.g. dl-phenylalanine methylester (dl-PAME), 2.23 vs 1.37; (R)(S)-1-phenylethylamine [(R)(S)-PEA], 2.09 vs 1.13; and (R)(S)-1-(1-naphthyl)ethylamines [(R)(S)-NEA], 5.19 vs 1.23. The results suggest that the position of COOH group on pyrrolidine moiety in the structures is one of the important factors for the efficient separation of a couple of the diastereomers.

Amines↗

PubMed2005

Development of an HPLC-fluorescence determination method for carboxylic acids related to the tricarboxylic acid cycle as a metabolome tool.

We report the simultaneous determination of the carboxylic acids related to the tricarboxylic acid (TCA) cycle, which plays an important role in producing adenosine triphosphate (ATP) and generating energy in mitochondria. Seven carboxylic acids from the TCA cycle, and pyruvic acid and 2-methylsuccinic acid, as an internal standard, were derivatized with a fluorescent reagent for carboxyl groups, 4-N,N-dimethylaminosulfonyl-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ), in the presence of 1-ethyl-3-(3-dimethylaminopropyl) carbodiimide and 4-N,N-dimethyaminopyridine as the coupling reagents, at 60 degrees C for 120 min. Subsequently, the excess DBD-PZ was removed efficiently using a cation-exchange cartridge, SDB-RPS (Empore). These fluorescent derivatives were separated well from each other on an octadecyl silica column (TSKgel ODS-80Ts, 250 x 4.6 mm, i.d.) with an eluent of acetonitrile-water containing 1% formic acid at a flow rate of 0.8 mL/min, and were detected fluorometrically at 560 nm, with excitation at 450 nm. The validation data were satisfactory in the range of 2.5-100 microm citric acid, isocitric acid, 2-oxoglutaric acid, succinic acid and fumaric acid. The detection limit (S/N = 3) for citric acid was 2 fmol on the column. The structures of these derivatives were confirmed by high-performance liquid chromatography-mass spectrometry, which proved that their carboxylic groups were completely labeled with DBD-PZ, except for oxaloacetic acid. This HPLC method was successfully applied to the analysis of TCA cycle metabolites in rat urine. The method will also be useful for metabolome research, such as for target analyses of metabolites with carboxyl groups, not only in urine but also in cells and organs.

Animals↗

PubMed2004

Hair analysis of histamine after fluorescence labeling by column-switching reversed-phase liquid chromatography with electrospray ionization mass spectrometry and application to human hair.

Sensitive determination of histamine (HA) in hair was carried out by column-switching reversed-phase high-performance liquid chromatography coupled with electrospray ionization mass spectrometry (HPLC-ESI-MS). HA was labeled with excess amounts of 4-(N,N-dimethylaminosulfonyl)-7-fluoro-2,1,3-benzoxadiazole (DBD-F) at 60 degrees C for 30 min in a mixture of 0.1 M borax (pH 9.3) and acetonitrile (CH(3)CN). The resulting DBD-HA derivative was roughly separated by a Mightysil RP-18 GP (100 x 2mm i.d., 3 microm) with an acidic mobile phase containing 0.1% trifluoroacetic acid. DBD-HA in the fraction flowing due to a position change in the six-port column-switching valve was then completely separated by a Wakopak Navi C30 (150 x 2mm i.d., 5 microm) with 20 mM AcONH(4)-CH(3)CN (8:2). The mass spectrometer was operated in the selected reaction monitoring (SRM) mode for the product ion (m/z 292) obtained from MS-MS measurement using the protonated molecular ion [M+H](+) (m/z 337) as the precursor ion. Good linearity was achieved from the calibration curve obtained by plotting peak area ratios of the internal standard (HA-d(4)) against the injected amounts of HA (1.66-16.6 pmol, r(2)=0.999). The coefficients of variation, at 1.66- and 16.6-pmol injections, were 5.6 and 3.7%, respectively (n=6). Furthermore, the detection limit was 0.167 pmol. The efficiency of the recommended procedure was identified from the determination in the rat hair root after intraperitoneal administration of HA. The proposed method was applied to HA determination in the hair shaft of Dark Agouti rats and healthy volunteers. The variations in the concentrations in 1mg of hair shaft were 0.80-1.84 pmol (mean+/-SD=1.33+/-0.33, n=12) in rats and 0.94-72.3 pmol (17.2+/-21.5, n=16) in humans. The determination of HA in the plasma of rats and humans was also performed successfully by this method. Because the proposed method provides good precision and trace detection of HA in hair, the analytical technique seems to be applicable for the determination of various biogenic amines in hair.

Animals↗

PubMed2004

Determination of rat blood S-D-lactoylglutathione by a column-switching high-performance liquid chromatography with precolumn fluorescence derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole.

A method for the determination of S-d-lactoylglutathione (SLG), an intermediate metabolite of the glyoxalase system, in rat blood is described. After hemolysis and deproteinization of 30 microl of rat blood, SLG in the blood was determined by a column-switching HPLC system with precolumn fluorescence derivatization with a fluorogenic reagent, 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F). Calibration curves for the determination of SLG showed a good linearity (r2 > 0.999) over the range of 20-100 pmol SLG spiked in rat blood samples. The accuracy was in the range of 97-104% (20-100 pmol SLG spiked in rat blood sample, N = 4). The detection limit was 8.12 fmol, and the quantitation limit was 27.07 fmol, respectively. The intra- and interday coefficients of variance were 4.63% (N = 5) and 9.98% (N = 5), respectively. The concentrations of SLG in whole blood from male Wistar-Kyoto rats (12 weeks old) were 3.48+/-0.78 microM (N = 4, mean+/-SE). In streptozotocin-induced diabetic rats, the concentration of SLG was significantly increased, approx 5-fold, compared with normal rats, suggesting that the metabolic flux of the glyoxalase system increases in red blood cells during hyperglycemia.

4-Chloro-7-nitrobenzofurazan↗

PubMed2004

A fully automated amino acid analyzer using NBD-F as a fluorescent derivatization reagent.

A fully automated amino acid analyzer using NBD-F (4- fluoro-7-nitro-2,1,3-benzoxadiazole) as a fluorescent derivatization reagent was developed. The whole analytical process was fully automated from derivatization, injection to HPLC separation and quantitation. The derivatization reaction conditions were re-evaluated and optimized. Amino acids were derivatized by NBD-F for 40 min at room temperature in the borate buffer (pH 9.5). The derivatives were separated within 100 min and fluorometrically detected at 540 nm with excitation at 470 nm. The detection limits for amino acids were in the range of 2.8-20 fmol. The calibration curves were linear over the range of 20 fmol to 20 pmol on column with the correlation coefficients of 0.999. The coefficients of variation were less than 5% at 3 pmol injection for all amino acids. Amino acids in rat plasma were determined by the proposed HPLC method.

4-Chloro-7-nitrobenzofurazan↗

PubMed2004

Intravenous administration of 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxy chroman (gamma-CEHC) to rats and determination of its plasma concentration and urinary sodium excretion.

A natriuretic hormone, 2,7,8-trimethyl-2-(beta-carboxyethyl)-6-hydroxy chroman (gamma-CEHC) was administered intravenously to male Sprague-Dawley rats and the plasma concentration of gamma-CEHC along with urinary sodium (Na+) excretion was investigated. The plasma gamma-CEHC concentrations were fluorimetrically determined by a column-switching HPLC method consisting of both phenyl and octadecyl silica columns, following a pre-column fluorescence derivatization with a fluorescence reagent, 4-N,N-dimethylaminosulfonyl-7-piperazino-2,1,3-benzoxadiazole (DBD-PZ). In rats fed with a high-NaCl (8.0%) diet, plasma gamma-CEHC concentrations rapidly decreased by 20% in 15-45 min after the administration of gamma-CEHC, while Na+ excretion gradually increased with time. Considering these results, the Na+ excretion effect appeared not to be associated with plasma gamma-CEHC concentration. In addition, attempts were made to examine a main urinary metabolite of gamma-CEHC, a large amount of 6-O-sulfated gamma-CEHC found to be present in the urine using an HPLC-tandem mass spectrometry. Thus, it is plausible that gamma-CEHC was easily metabolized to 6-O-sulfated metabolite and excreted into urine in rats.

Animals↗

PubMed2004

Simultaneous determination of D- and L-serine in rat brain microdialysis sample using a column-switching HPLC with fluorimetric detection.

Both D- and L-serine in rat brain microdialysis sample were simultaneously determined by pre-column fluorescence derivatization with 4-fluoro-7-nitro-2,1,3-benzoxadiazole (NBD-F), separation of the derivatives on ODS column, TSKgel ODS-80TsQA, followed by Pirkle type chiral columns, Sumichiral OA-2500 (S), which gave a sufficient enantiomeric separation of NBD-D-serine and NBD-L-serine, and fluorimetric detection at a wavelength of 540 nm with an excitation wavelength of 470 nm. The peaks of NBD-D-serine and NBD-L-serine in the rat brain microdialysis sample were clearly found, and the validation study showed satisfactory results; the precision and accuracy were within 5.14 and 109%, respectively. Using the proposed HPLC method, the time-course profile of D-serine concentration in rat prefrontal cortex following intraperitoneal administration of D-serine was investigated. As a consequence, D-serine appeared to be rapidly distributed in the brain, and then decreased gradually with time in the extracellular fluid of the rat prefrontal cortex. The proposed HPLC method will be useful for in vivo studies on D-serine, which acts as a coagonist for N-methyl-D-aspartate receptor, to the extracellular fluid of rat brain.

4-Chloro-7-nitrobenzofurazan↗

PubMed2004

Possible role of D-serine in the pathophysiology of Alzheimer's disease.

Several lines of evidence suggest that D-serine may function as an endogenous agonist of the glycine site on the N-methyl-D-aspartate (NMDA) receptor that has been implicated in the pathophysiology of Alzheimer's disease (AD). The purpose of the study was to determine whether serum levels of D- and L-serine in patients with AD are altered as compared with normal controls. Serum levels of D- and L-serine in patients of AD and age- and gender-matched normal controls were determined using a high-performance liquid chromatography (HPLC). Serum levels of D-serine in the patients with AD were slightly (z=-1.77, p=0.078) lower than those of normal controls. In contrast, serum levels of L-serine in the patients were slightly (z=-1.73, p=0.083) higher than those of controls. In addition, the percentage (%) of D-serine in the total (L+D) serine in the patients was significantly (z=-2.36, p=0.018) lower than that of controls. The present study suggests that the reduced activity of serine racemase, an enzyme catalyzing the formation of D-serine from L-serine may play a role in the pathophysiology of AD.

Aged↗

PubMed2003

Determination of serum D-lactic and L-lactic acids in normal subjects and diabetic patients by column-switching HPLC with pre-column fluorescence derivatization.

d-Lactic and l-lactic acids were simultaneously determined by means of a column-switching high-performance liquid chromatography (HPLC) with fluorescence detection. As a fluorescence reagent, 4-nitro-7-piperazino-2,1,3-benzoxadiazole (NBD-PZ) was employed for the fluorescence derivatization of lactic acid. The proposed HPLC system adopted both octylsilica (Cadenza CD-C8) and amylose-based chiral columns (CHIRALPAK AD-RH), which proved to give a sufficient enantiomeric separation of the lactic acid derivatives with a separation factor ( alpha) of 1.32 and a resolution ( R(s)) of 1.98. Moreover, the features of the first elution of d-lactic acid peak in the proposed HPLC were convenient for the determination of trace amount of serum d-lactic acid, which is known to increase under diabetes. Intra-day and inter-day accuracies were in the range of 90.5-101.2 and 89.0-100.7%, and the intra-day and inter-day precisions were 0.3-1.2 and 0.4-4.8%, respectively. The proposed method was applied to determine d-lactic and l-lactic acids in human serum of normal subjects and diabetic patients, showing that both d-lactic and l-lactic acid concentrations were significantly increased in the serum of diabetic patients ( n=31) as compared with normal subjects ( n=21). This fact was found for the first time owing to the development of the proposed HPLC method which is able to determine d-lactic and l-lactic acid simultaneously. Finally, serum d-lactic acid concentrations determined by the proposed HPLC method were compared with those from a reported enzymatic assay, and the smaller p value between normal subjects and diabetic patients was shown by the proposed HPLC method.

Adult↗

PubMed2003

Recent progress in derivatization methods for LC and CE analysis.

The derivatization procedure with a suitable fluorescence or chemiluminescence reagent is performed for the purpose of increasing the detection sensitivity and selectivity, in high-performance liquid chromatography (HPLC) and/or capillary electrophoresis (CE). In this article, recent derivatization methods and their applications to biosamples are described. In HPLC, femto mol order of mass detection limits are obtained by derivatization. Regarding the fluorescence reagents, the use of water-soluble reagents has been effective to avoid an undesired adsorption in the process of determination of peptides. In CE, the advantages of having extremely low mass detection limits (ranging from atto to yocto mol level) and requiring only a very short analysis time (less than a few minutes) are made possible by using laser-induced fluorescence or near infra-red detections.

Chromatography, High Pressure Liquid↗

PubMed2003

Decreased serum levels of D-serine in patients with schizophrenia: evidence in support of the N-methyl-D-aspartate receptor hypofunction hypothesis of schizophrenia.

BACKGROUND: The hypofunction of the N-methyl-D-aspartate (NMDA) subtype of glutamate receptors has been implicated in the pathophysiology of schizophrenia. Several lines of evidence suggest that D-serine may function as an endogenous agonist of the glycine site of the NMDA receptor. The aim of this study was to examine whether serum levels of D- and L-serine in patients with schizophrenia are different from those of healthy controls. METHODS: Forty-two patients with schizophrenia and 42 age- and sex-matched healthy controls were enrolled in this study. Symptoms were assessed using the Brief Psychiatric Rating Scale. Serum levels of total serine and D- and L-serine were measured by high-performance liquid chromatography. RESULTS: Serum levels of D-serine in the patients with schizophrenia were significantly (z = -3.30, P =.001) lower than those of healthy controls. In contrast, serum levels of total (D and L) serine (z = -2.40, P =.02) and L-serine (z = -2.49, P =.01) in the schizophrenic patients were significantly higher than those of controls. In addition, the percentage of D-serine in the total serine in the schizophrenic patients was significantly (z = -4.78, P<.001) lower than that of controls, suggesting that the activity of serine racemase, an enzyme catalyzing the formation of D-serine from L-serine, may have been reduced in the schizophrenic patients. CONCLUSIONS: Reduced levels of D-serine may play a role in the pathophysiology of schizophrenia, and serum D- and L-serine levels might provide a measurable biological marker for schizophrenia.

Adolescent↗