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Biomedical subjects

M Tatsuno

Publications and source records attributed to M Tatsuno.

At least 19 recordsLinked to original sources
PubMed2002

Urinary excretion of selegiline N-oxide, a new indicator for selegiline administration in man.

1. The metabolism of selegiline (SG) has been studied by investigating the time-course of urinary excretion of SG and its metabolites using high-performance liquid chromatography-electrospray ionization mass spectrometry (LC-ESI MS) in combination with solid-phase extraction. 2. The excretion profiles of SG and its four major metabolites, selegiline-N-oxide (SGO), N-desmethylselegiline (DM-SG), methamphetamine (MA) and amphetamine (AP), were investigated in six healthy volunteers after oral administrations of SG hydrochloride in a single dose of 2.5 or 7.5mg, and a repeat twice-daily dose of 5.0 mg day(-1) (for 3 days). 3. The cumulative amount of SGO excreted within approximately the first 8-12h was comparable with MA, and the amount in the first 72 h was 2.0-7.8 times larger (2.8-13.2% of the dose) than that of DM-SG. 4. These results demonstrate that SGO can be used in place of DM-SG, which is known to be a main specific metabolite of SG, as a new indicator for the discrimination of SG use compared with MA abuse.

Adrenergic Uptake Inhibitors↗
PubMed2001

Simultaneous determination of selegiline-N-oxide, a new indicator for selegiline administration, and other metabolites in urine by high-performance liquid chromatography-electrospray ionization mass spectrometry.

In order to discriminate selegiline (SG) use from methamphetamine (MA) use, the urinary metabolites of SG users have been investigated using high-performance liquid chromatography (HPLC)-electrospray ionization mass spectrometry (HPLC-ESI-MS). Selegiline-N-oxide (SGO), a specific metabolite of SG, was for the first time detected in the urine, in addition to other metabolites MA, amphetamine (AP) and desmethylselegiline (DM-SG). A combination of a Sep-pak C18 cartridge for the solid-phase extraction, a semi-micro SCX column (1.5 mm I.D.x 150 mm) for HPLC separation and ESI-MS for detection provided a simple and sensitive procedure for the simultaneous determination of these analytes. Acetonitrile-10 mM ammonium formate buffer adjusted to pH 3.0 (70:30, v/v) at a flow-rate of 0.1 ml/min was found to be the most effective mobile phase. Linear calibration curves were obtained over the concentration range from 0.5 to 100 ng/ml for all the analytes by monitoring each protonated molecular ion in the selected ion monitoring (SIM) mode. The detection limits ranged from 0.1 to 0.5 ng/ml. Upon applying the scan mode, 10-20 ng/ml were the detection limits. Quantitative investigation utilizing this revealed that SGO was about three times more abundant (47 ng/ml, 79 ng/ml) than DM-SG in two SG users' urine samples tested here. This newly-detected, specific metabolite SGO was found to be an effective indicator for SG administration.

Chromatography, High Pressure Liquid↗
PubMed2001

Column-switching high-performance liquid chromatography-electrospray ionization mass spectrometry for identification of heroin metabolites in human urine.

In order to prove heroin (DAM) use, a simple, rapid and sensitive analytical method has been established by combining semi-microcolumn HPLC, a column switching technique and electrospray ionization mass spectrometry (ESI-MS). Urine samples were directly introduced to the system, and endogenous urinary constituents were removed by using on-line column switching solid-phase extraction with a strong cation-exchange (SCX) cartridge column (2.0 mm I.D. x 10 mm). Heroin and its metabolites enriched on the top of the column were then successfully analyzed with excellent separation by use of a SCX semi-microcolumn (1.5 mm I.D. x 150 mm), accompanied by ESI mass spectral detection. The proposed conditions are as follows: mobile phase, 10 mM ammonium acetate (pH 6.0)-acetonitrile (30:70, v/v) (for main separation) and 30 mM ammonium acetate (for trapping); flow-rates, 120 microl/min (for main separation) and 200 microl/min (for trapping); capillary voltage, +4.5 kV; cone voltage, 50 V. Linear calibration curves were obtained in the selected ion monitoring (SIM) mode using protonated molecular ions (m/z 370 for DAM, m/z 328 for MAM and m/z 286 for MOR) over the concentration ranges from 10 to 1000 ng/ml for morphine (MOR) and 1-100 ng/ml for DAM and 6-acetylmorphine (MAM). The detection limits were 0.1-3 ng/ml. Upon applying the scan mode, 2-30 ng/ml were the detection limits. The present HPLC-ESI-MS method was successfully applied to the determination of opiates in users' urine samples.

Chromatography, High Pressure Liquid↗
PubMed2000

A novel degradative pathway of 2-nitrobenzoate via 3-hydroxyanthranilate in Pseudomonas fluorescens strain KU-7.

A bacterial strain KU-7, identified as a Pseudomonas fluorescens by 16S rDNA sequencing, was one of the 12 new isolates that are able to grow on 2-nitrobenzoate as a sole source of carbon, nitrogen, and energy. Resting cells of KU-7 were found to accumulate ammonia in the medium indicating that degradation of 2-NBA proceeds through a reductive route. Metabolite analyses by thin layer chromatography and high pressure liquid chromatography indicated that 3-hydroxyanthranilate is an intermediate of 2-nitrobenzoate metabolism in KU-7 cells. This offers an alternative route to 2-nitrobenzoate metabolism since anthranilate (2-aminobenzoate) or catechol were detected as intermediates in other bacteria. Crude extracts of KU-7 cells converted 2-nitrobenzoate to 3-hydroxyanthranilate with oxidation of 2 mol of NADPH. Ring cleavage of 3-hydroxyanthranilate produced a transient yellow product, identified as 2-amino-3-carboxymuconic 6-semialdehyde, that has a maximum absorbance at 360 nm. The initial enzymes of the 2-nitrobenzoate degradation pathway were found to be inducible since succinate-grown cells produced very low enzyme activities. A pathway for 2-nitrobenzoate degradation in KU-7 was proposed.

3-Hydroxyanthranilic Acid↗
PubMed2000

Effect of brief maximal exercise on circulating levels of interleukin-12.

Interleukin-12 (IL-12) is a cytokine that was originally identified as natural killer cell stimulatory factor. It induces the activity of T-helper 1 (Th1) cells and exhibits strong anti-tumor activity. In this study, we studied the effects of brief anaerobic maximal exercise on circulating levels of IL-12. Six healthy males [mean (SD) 25.2 (2.6) years] performed a modified Wingate test exercise (resistance 0.075 kg/kg of body mass). The exercise consisted of five bouts of maximal cycling for 10 s, with rest intervals of 50 s between them. Blood samples were taken before, immediately after, 30 min after, 60 min after and 120 min after the exercise. Plasma concentrations of IL-12 were measured using an enzyme-linked immunosorbent assay. Data were corrected for hemoglobin and hematocrit measurements. Plasma concentrations of IL-12 averaged [mean (SD)] 234.2 (40.9) pg/ml before, 305.2 (62.1) pg/ml immediately after, 202.8 (24.2) pg/ml 30 min after, 239.7 (35.1) pg/ml 60 min after, and 199.6 (49.2) pg/ml 120 min after the exercise. We showed that plasma concentrations of IL-12 increased significantly immediately after brief anaerobic maximal cycle ergometer exercise (P < 0.01).

Adult↗
PubMed1999

On-line solid-phase extraction liquid chromatography-continuous flow frit fast atom bombardment mass spectrometric and tandem mass spectrometric determination of hydrolysis products of nerve agents alkyl methylphosphonic acids by p-bromophenacyl derivatization.

For proof of the presence of chemical warfare agents sarin, soman and VX, a rapid, accurate and sensitive method which allows us to determine their hydrolysis products ethyl methylphosphonic acid, isopropyl methylphosphonic acid and pinacolyl methyl phosphonic acid was explored by using continuous flow frit fast atom bombardment (FAB) LC-MS and LC-MS-MS. After derivatization of analytes with p-bromophenacyl bromide, LC-MS-MS analyses for screening were performed by a flow injection method. The three alkyl methylphosphonic acids (AMPAs) were eluted within 5 min, and the detection limits for the three AMPAs ranged from 1 to 5 ng/ml. For confirmation of the screening results, LC-MS-MS analysis with chromatographic separation was conducted by using a narrow bore column. The three AMPAs were all eluted with excellent separation within 25 min, and the detection limits ranged from 1 to 20 ng/ml. Quantitative measurement was performed by LC-MS in selected ion monitoring (SIM) mode with chromatographic separation. Linear calibration curves were obtained for the three AMPAs and the detection limits ranged from 0.5 to 3 ng/ml. The relative standard deviation for peak area ranged from 3.4 to 6.0% at 50 ng/ml for the three AMPAs.

Chemical Warfare Agents↗
PubMed1999

Liquid jets, accelerated thrombolysis: a study for revascularization of cerebral embolism.

A prior study has reported that a rapid recanalization therapy of cerebral embolism, using liquid jet impacts generated by the interaction of gas bubbles with shock waves, can potentially penetrate through thrombi in as little as a few microseconds with very efficient ablation (Kodama et al. 1997). The present study was undertaken to examine the liquid jet impact effect on fibrinolysis in a tube model of an internal carotid artery. First, the conditions for generating the maximum penetration depth of liquid jets in the tube were investigated. Gelatin was used to mimic thrombi. The shock wave was generated by detonating a silver azide pellet weighing about a few micrograms located in a balloon catheter. The collapse of the inserted gas bubbles and the subsequent liquid jet formation were recorded with high-speed photography. Second, thrombi were formed using fresh human blood from healthy volunteers. The fibrinolysis induced by the liquid jet impact with urokinase was explored. This was conducted under selected conditions based on the experiment using the gelatin. Fibrinolysis was calculated as the percentage of the weight loss of the thrombus. Fibrinolysis with urokinase alone and with a single liquid jet impact with urokinase was 1.9 +/- 3.7% (n = 16) and 20.0 +/- 9.0% (n = 35), respectively, for an incubation time of 60 min. Statistical differences were obtained between all groups (ANOVA). These results suggest that liquid jet impact thrombolysis has the potential to be a rapid and effective therapeutic modality in recanalization therapy for patients with cerebral embolism and other clinical conditions of intra-arterial thrombosis.

Carotid Artery, Internal↗
PubMed1999

Correlation between magnetic resonance imaging and clinical profiles of periventricular leukomalacia.

Magnetic resonance imaging (MRI) findings of 70 children with periventricular leukomalacia (PVL), examined between 1 year 2 months and 8 years of age (mean: 2 years 4 months of age), were analysed. Neurological assessments were made between 1 year 3 months and 15 years (mean: 4 years 9 months). The possible correlations between MRI findings and clinical profiles of PVL were investigated using three parameters of the MRI findings. The grade of ventriculomegaly correlated well with the severity of cerebral palsy (CP) but not with the severity of mental impairment. The grade of reduction of periventricular white matter correlated well with the severity of CP and mental impairment, and is the most reliable parameter for neurological prognosis. The degree of periventricular hyperintensity on T2-weighted images did not correlate well with severity of CP, but correlated to some degree with mental impairment. There was a significantly lower degree of periventricular hyperintensity in children at less than 28 weeks of gestation than at 28 or more weeks of gestation, but no significant difference in other parameters. The periventricular hyperintensity should be evaluated in view of the gestational age.

Cerebral Ventricles↗
PubMed1998

Maturational change of KCl-induced Ca2+ increase in the rat brain synaptosomes.

To investigate maturational change in the susceptibility of voltage-dependent calcium (Ca2+) channels (VDCC) in the brain to excessive depolarization, which is likely to occur during hypoxia or ischemia, we studied depolarization-induced increases in Ca2+ concentration in cortical synaptosomes ([Ca2+]i) obtained from young (8, 15, 22, 36, and 43-day-old) and adult rats using fura 2-AM as a Ca2+ indicator. The effects of Ca2+ antagonists on the increase were also studied. The maximal increase in [Ca2+]i caused by 50 mM KCl-induced depolarization was significantly lower in 8-day-old rats (73.3 nM) compared with that in adult rats (133.6 nM). On the other hand, the time necessary for [Ca2+]i to decrease to 50% of its maximal level (tau) was significantly shorter in immature rats compared with that in adult rats and was particularly short in 8- and 15-day-old rats (0.28 and 0.40 min vs. 3.85 for adult rats). The maximal increase in [Ca2+]i in 22-day-old rats and tau in adult rats were markedly reduced by verapamil, omega-agatoxin IVA, and omega-conotoxin GVIA (antagonists of L-, P-, and N-type Ca2+ channels, respectively) to similar extents, while a mixture of the three antagonists markedly decreased both maximal increase and tau in 8- and 22-day-old and adult rats. These results indicate that depolarization-induced Ca2+ influx through VDCCs in immature rat brain is less pronounced than that in adult rats, and suggest that the susceptibility of all of L-, N-, and P-type Ca2+ channels is increased during maturation in the first few weeks after birth. This lower susceptibility to depolarization might be involved in the resistance to hypoxia in immature animals.

Aging↗
PubMed1998

Identification of metabolites of nerve agent VX in serum collected from a victim.

A human serum sample collected from a victim of the Osaka VX incident was analyzed according to our developed technique for metabolites of VX. Gas chromatography-mass spectrometry (GC-MS) in full-scan electron impact and chemical ionization modes were used, and, for more reliable confirmation, GC-MS-MS was also employed. In the serum sample, both ethyl methylphosphonic acid and 2-(diisopropylamino-ethyl)methyl sulfide were detected. These results indicated that the techniques using GC-MS and GC-MS-MS were applicable to biological samples such as serum. These results also provide the first documented, unequivocal identification of the specific metabolites of VX in victim's serum and, furthermore, clarify a part of the metabolic pathway of VX in the human body.

Adult↗
PubMed1998

National survey of periventricular leukomalacia in Japan.

BACKGROUND: Clarification of the present status of periventricular leukomalacia (PVL) in Japan. METHODS: Questionnaires were mailed to the leading neonatal intensive care units (NICU) and rehabilitation centers for children. RESULTS: The incidence of PVL in the group of surviving preterm infants of gestational ages less than 33 weeks was 4.8-4.9% on ultrasound and 7.7-7.9% on magnetic resonance imaging and/or computed tomography. The incidence of PVL did not decrease between 1990 and 1994. The incidence of PVL in the NICU varied from 0 to 47.1%. Infants from multiple pregnancies had a higher incidence (9.1%) of PVL than those from single pregnancies (6.2%). The proportion of PVL in all patients in rehabilitation centers with cerebral palsy (CP) has increased recently. CONCLUSIONS: It was roughly calculated that about 750 cases of CP with PVL occurred annually in Japan, thus accounting for about one-third of the total number of cases of CP.

Cerebral Palsy↗
PubMed1998

Augmentation of mitochondrial reduced glutathione by S-adenosyl-L-methionine administration in ischemia-reperfusion injury of the rat steatotic liver induced by choline-methionine-deficient diet.

We examined whether warm ischemia-reperfusion (I/R) damage of the rat steatotic liver can be reduced by administration of S-adenosyl-L-methionine (SAMe). We examined the effect of SAMe on the mitochondrial reduced-glutathione (GSH) pool. Sixty minutes of partial left lobar vascular clamping followed by 2 h of reperfusion were employed for a model of hepatic warm ischemia. Either 5% dextrose or SAMe was injected intraperitoneally 2 h before I/R in steatotic rats (S-D5% or S-SAMe group). Serum liver enzyme concentrations 2 h after reperfusion were significantly lower in the S-SAMe group than in the S-D5% group. The cytosolic and mitochondrial GSH concentrations after I/R were significantly higher in the S-SAMe group than in the S-D5% group (p < 0.05). The cytosolic and mitochondrial oxidized-glutathione/GSH ratios after I/R were significantly greater in the S-D5% group than in the S-SAMe group (p < 0.01). The adenosine triphosphate concentration was higher in the S-SAMe group than in the S-D5% group (p = 0.0515). These results show that hepatocellular and mitochondrial oxidative stress after I/R in the steatotic liver can be reduced by administration of SAMe. The results also show that mitochondrial function and hepatocellular integrity can be restored by administration of SAMe in steatotic rats.

Animals↗
PubMed1997

Determination of the main hydrolysis products of organophosphorus nerve agents, methylphosphonic acids, in human serum by indirect photometric detection ion chromatography.

For the verification of the use of chemical warfare agents (CWA), sarin, soman and VX, a simple rapid and accurate method which allows us to simultaneously determine their degradation products, isopropyl methylphosphonic acid (IPMPA), pinacolyl methylphosphonic acid (PMPA), ethyl methylphosphonic acid (EMPA) and methylphosphonic acid (MPA), in human serum, was explored by indirect photometric detection ion chromatography (IPD-IC) which employs an anion-exchange column. IC analysis was performed after sample preparation with an Ag+-form cation-exchange resin cartridge, and the four methylphosphonic acids could be separated well. The proposed conditions are as follows: eluent, 0.5 mM phthalic acid-0.1 mM Tris (hydroxymethyl) aminomethane-5% acetonitrile; flow-rate, 1.0 ml/min; temperature, 50 degrees C; UV detector, 266 nm. All four methylphosphonic acids were eluted within 30 min with hardly any disturbance by impurities in the serum. Linear calibration curves were obtained for MPA, EMPA and IPMPA in the concentration range from 50 ng/ml to 1 microg/ml and for PMPA from 100 ng/ml to 1 microg/ml. The relative standard deviation for the methylphosphonic acids ranged from 3.8 to 6.9% at 500 ng/ml and the detection limits were 40 ng/ml for MPA, EMPA and IPMPA and 80 ng/ml for PMPA. The method would be suitable for analysis of human serum samples.

Chemical Warfare Agents↗
PubMed1997

Application of ion mobility spectrometry to the rapid screening of methamphetamine incorporated in hair.

Using ion mobility spectrometry (IMS), a simple, sensitive and rapid screening for methamphetamine (MA) incorporated in user's hair has been developed. To completely unbind MA from hair matrix and to achieve its effective vaporization for the IMS detection, the hair sample was digested in 5 M NaOH (methanol-water, 4:1, v/v) solution prior to IMS measurement. MA in hair was semi-quantitatively detected by monitoring the digested hair sample employing dibenzylamine (DBA) as internal standard. The minimum amount of hair sample required was 2 mg and its digested sample was ample for four IMS measurements. The detection limit of MA in hair was 0.5 ng mg(-1). This proposed method was applicable to the semi-quantitative detection of MA in users' hair samples, and to the sectional analysis for MA in a limited amount of user's hair. The IMS results obtained were in good agreement with their GC-MS determination.

Hair↗
PubMed1997

Determination of the main hydrolysis product of O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate, ethyl methylphosphonic acid, in human serum.

For the unequivocal proof of the use of a nerve agent O-ethyl S-2-diisopropylaminoethyl methylphosphonothiolate (VX), a rapid, accurate and sensitive method which allows us to identify its main hydrolysis product ethyl methylphosphonic acid (EMPA) in human serum was explored by GC-MS. GC-MS analysis was performed after solvent extraction with acetonitrile in acidic conditions from the serum sample, which was previously deproteinized by micro-ultrafiltration, and subsequent tert.-butyldimethylsilyl derivatization with N-methyl-N-(tert.-butyldimethylsilyl)trifluoroacetamide (MTBSTFA) with 1% tert.-butyldimethylsilyl chloride (t-BDMSC). Linear calibration curves were obtained in the concentration range from 50 to 500 ng/ml for EMPA in the full-scan EI mode and from 5 to 50 ng/ml for EMPA in the SIM EI mode. The relative standard deviation obtained at a sample concentration of 50 ng/ml was 8.4% in the full-scan mode and 7.3% in the SIM mode. Upon applying the full-scan EI and CI mode, 40 ng/ml and 80 ng/ml were the detection limits. Using the SIM-EI mode, in which the ion at m/z 153 was chosen, the limit was 3 ng/ml.

Cholinesterase Inhibitors↗
PubMed1997

The effects of N-acetylcysteine and anti-intercellular adhesion molecule-1 monoclonal antibody against ischemia-reperfusion injury of the rat steatotic liver produced by a choline-methionine-deficient diet.

Abundant fat in the liver has been implicated in poor outcome after liver transplantation or liver surgery, but the reasons for this association are still unclear. The aim of the present study was to examine mechanisms that may be involved in hepatic dysfunction after ischemia-reperfusion (I/R) of the steatotic rat liver. Steatosis was produced by a choline-methionine-deficient (CMDD) diet. In the first experiment, isolated perfused rat livers, subjected to 24-hour cold storage followed by 120-minute reperfusion, were used to investigate hypothermic I/R injury of the steatotic rat liver. In the second experiment, livers were subjected to 60-minute partial left lobar vascular clamping to allow study of normothermic I/R injury. In the first experiment, compared with normal nonsteatotic liver, steatotic livers showed significantly greater injury, as assessed by amounts of hepatic enzymes released into the perfusate, bile production, the concentrations of reduced glutathione (GSH) in the perfusate, as well as in the livers themselves, and electron microscopic findings of sinusoidal microcirculatory injury. The addition of N-acetylcysteine (NAC), a precursor of glutathione, to the liver before cold storage significantly improved these parameters in steatotic livers. The second experiment showed that, compared with nonsteatotic livers, steatotic livers had lower concentrations of GSH and impaired rates of bile production. There was also evidence of increased oxidative stress in polymorphonuclear leukocytes (PMNLs) in liver or peripheral blood of rats with fatty livers. An anti-rat intercellular adhesion molecule-1 (ICAM-1) monoclonal antibody inhibited neutrophil infiltration into pericentral sinusoids and improved these parameters in the steatotic rats. We conclude that sinusoidal microcirculatory injury is involved in hypothermic I/R injury, that oxidative stress produced by PMNLs is involved in normothermic I/R injury, and that NAC and anti-rat ICAM-1 monoclonal antibody restore liver integrity in I/R injury.

Acetylcysteine↗
PubMed1996

Simultaneous determination of illicit drugs in human urine by liquid chromatography-mass spectrometry.

The method for simultaneous determination and confirmation of illicit drugs (e.g., methamphetamine, amphetamine, ephedrine, methylephedrine, morphine, morphine-3-glucuronide, morphine-6-glucuronide, 6-acetylmorphine, cocaine, and benzoylecgonine) in human urine by thermospray liquid chromatography-mass spectrometry (LC-MS) was studied. The LC-MS separation was performed on a reversed phase column (L-column ODS; 150 mm x 4.6-mm i.d.) using a gradient mobile phase system of 100mM ammonium acetate for 1 min then linear ramps to 100mM ammonium acetate including 40% acetonitrile at 20 min. Extraction was conducted by solid-phase extraction using a Sep-pak C18 cartridge. The drugs were eluted with 2 mliters of 40% acetonitrile in 100 mM ammonium acetate, pH3 (adjusted with acetic acid), from the cartridge. A 50-microL volume of the eluate was injected into the LC-MS. The recoveries by this extraction were 88 to 99%. The mass spectra of methamphetamine, amphetamine, ephedrine, methylephedrine, morphine, 6-acetylmorphine, cocaine, and benzoylecgonine showed the quasi-molecular [M + H]+ ion as the base peak, whereas morphine-3-glucuronide and morphine-6-glucuronide showed [MH-glucuronide]+ ion as the base peak. The calibration graphs were linear and reproducible. Detection limits of these drugs ranged from 2 to 40 ng/mliters by selected ion monitoring (SIM) mode and from 50 to 400 ng/mliters by scan mode. The coefficients of variation for the analysis of these drugs ranged from 4.5 to 9.5% at a concentration of 0.4 micrograms/mliters (n = 10).

Chromatography, Liquid↗