Hitoshi Tsuchihashi

Osaka Medical College, Takatuki, Ōsaka, Japan

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Publications (103)227.89 Total impact

  • [Show abstract] [Hide abstract]
    ABSTRACT: Little information is available on the amounts of hypnotics incorporated into hair after a single administration and about effective analytical procedures to document cases like drug-facilitated sexual assaults. To obtain basic information, single-hair specimens from a volunteer who took a single dose of 10-mg zolpidem (ZP) were analyzed by a newly established liquid chromatography–tandem mass spectrometry procedure, using a one-pot pulverization extraction method. The detection limit of ZP was 50 fg/2-cm single hair, and ZP in each segment was determined for the single black hair specimens (n = 15). ZP was detectable in 14 hairs (positive for all the proximal 0–2 cm segments, negative for all 2–4 cm segments), but was not detected in a single hair (probably in the telogen stage). The amounts of ZP detected in each positive 2-cm segment of single hair ranged from 27 to 63 pg (average 43 pg). The estimated total incorporation of ZP in the scalp hair (black hair ~110,000 strands) was about 4.7 μg, which corresponds to about 0.06 % of the single 10-mg dose (8.03 mg as free ZP). In addition, the direct detection of single-dose ZP incorporated in hair and its imaging were successfully achieved by matrix-assisted laser desorption ionization-mass spectrometry. It is suggested that a combination of these methodologies will provide the highest-level evidence to document such exposure to a hypnotic drug.
    Forensic Toxicology 12/2014; · 5.76 Impact Factor
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    ABSTRACT: Traumatic cerebellar hemorrhagic contusions are infrequent, and the pathogenic mechanism involves a coup injury that is associated with motor vehicle accidents in most cases. Traumatic basal subarachnoid hemorrhage (TBSAH) is commonly reported after blunt trauma to the neck or unrestricted movement of the head, and the source of the hemorrhage is most frequently identified in the vertebrobasilar arteries. A 55-year-old woman who was addicted to alcohol was found dead in her bed. She had a bruise on the left side of her posterior parietal region, and autopsy revealed massive subarachnoid hemorrhage at the base of the brain; the hematoma was strongly attached to the right lower surface of the cerebellar hemisphere. No ruptured cerebral aneurysms, arteriovenous malformations or vertebrobasilar artery leakage were detected. Hemorrhagic cerebellar contusions were regarded as the source of the TBSAH. This is the first report of TBSAH suspected to have been caused by contrecoup cerebellar contusions.
    Legal Medicine 03/2014; · 1.44 Impact Factor
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    ABSTRACT: Urinary metabolites of α-pyrrolidinovalerophenone (α-PVP) in humans were investigated by analyzing urine specimens obtained from abusers. Unambiguous identification and accurate quantification of major metabolites were realized using gas chromatography–mass spectrometry and liquid chromatography-tandem mass spectrometry with newly synthesized authentic standards. Two major metabolic pathways were revealed: (1) the reduction of the β-keto moiety to 1-phenyl-2-(pyrrolidin-1-yl)pentan-1-ol (OH-α-PVP, diastereomers) partly followed by conjugation to its glucuronide, and (2) the oxidation at the 2″-position of the pyrrolidine ring to α-(2″-oxo-pyrrolidino)valerophenone (2″-oxo-α-PVP) via the putative intermediate α-(2″-hydroxypyrrolidino)valerophenone (2″-OH-α-PVP). Of the metabolites retaining the structural characteristics of the parent drug, OH-α-PVP was most abundant in most of the specimens examined.
    Forensic Toxicology 01/2014; 32(1). · 5.76 Impact Factor
  • Japanese Journal of Forensic Science and Technology 01/2014; 19(2):77-89.
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    ABSTRACT: A rapid and convenient extraction method has been developed for the determination of various drugs and metabolites of forensic interest in blood by modifying the dispersive solid-phase extraction method "QuEChERS". The following 13 analytes with various chemical properties were used for the method development and its validation: amphetamine, methamphetamine, zolpidem, the carboxylate-form major metabolite of zolpidem M-1, flunitrazepam, 7-aminoflunitrazepam, phenobarbital, triazolam, α-hydroxytriazolam, brotizolam, α-hydroxybrotizolam, chlorpromazine, and promethazine. The modification of the QuEChERS method includes the use of relatively large amounts of inorganic salts in order to coagulate blood, which allows easy isolation of the organic extract phase. A combination of 100mg anhydrous magnesium sulfate as a dehydrating agent, 50mg sodium chloride as a salting-out agent, and 500μL acetonitrile containing 0.2% acetic acid as the organic solvent provided the optimum conditions for processing a 100μL whole blood sample. The recoveries of the analytes spiked into whole blood at 0.5μg/mL ranged between 59% and 93%. Although the addition of the graphitized carbon Envi-carb for cleanup decreased the recoveries of zolpidem and its carboxylate-form metabolite M-1, it was very effective in avoiding interferences by cholesterol. The present method can provide a rapid, effective, user-friendly, and relatively hygienic method for the simultaneous extraction of a wide range of drugs and metabolites in whole blood specimens.
    Forensic science international 10/2013; 232(1-3):40-5. · 2.10 Impact Factor
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    ABSTRACT: The metabolic profiles of urine and blood plasma in drug-addicted rat models based on morphine (MOR), methamphetamine (MA), and cocaine (COC)-induced conditioned place preference (CPP) were investigated. Rewarding effects induced by each drug were assessed by use of the CPP model. A mass spectrometry (MS)-based metabolomics approach was applied to urine and plasma of MOR, MA, and COC-addicted rats. In total, 57 metabolites in plasma and 70 metabolites in urine were identified by gas chromatography-MS. The metabolomics approach revealed that amounts of some metabolites, including tricarboxylic acid cycle intermediates, significantly changed in the urine of MOR-addicted rats. This result indicated that disruption of energy metabolism is deeply relevant to MOR addiction. In addition, 3-hydroxybutyric acid, L-tryptophan, cystine, and n-propylamine levels were significantly changed in the plasma of MOR-addicted rats. Lactose, spermidine, and stearic acid levels were significantly changed in the urine of MA-addicted rats. Threonine, cystine, and spermidine levels were significantly increased in the plasma of COC-addicted rats. In conclusion, differences in the metabolic profiles were suggestive of different biological states of MOR, MA, and COC addiction; these may be attributed to the different actions of the drugs on the brain reward circuitry and the resulting adaptation. In addition, the results showed possibility of predict the extent of MOR addiction by metabolic profiling. This is the first study to apply metabolomics to CPP models of drug addiction, and we demonstrated that metabolomics can be a multilateral approach to investigating the mechanism of drug addiction.
    Analytical and Bioanalytical Chemistry 08/2013; · 3.66 Impact Factor
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    ABSTRACT: Mass spectrometric differentiation of the six isomers of mono-methoxyethylamphetamines (MeO-EAs) and mono-methoxydimethylamphetamines (MeO-DMAs) by gas chromatography–electron ionization–tandem mass spectrometry (GC–EI–MS–MS) was investigated. Based on their EI-mass spectra, the fragment ions at m/z 121 and 72 were selected as precursor ions for their regioisomeric and structurally isomeric differentiation, respectively. Collision-induced dissociation provides intensity differences in product ions among the isomers, enabling mass spectrometric differentiation of the isomers. Furthermore, high reproducibility of the product ion spectra at the optimized collision energy was confirmed, demonstrating the reliability of the method. To our knowledge, this is the first report on mass spectrometric differentiation of the six isomers of MeO-EAs and MeO-DMAs by GC–EI–MS–MS. Isomeric differentiation by GC–EI–MS–MS has a high potential to discriminate isomers of newly encountered designer drugs, making GC–MS–MS a powerful tool in the forensic toxicology field.
    Forensic Toxicology 07/2013; 31(2). · 5.76 Impact Factor
  • Kei Zaitsu, Munehiro Katagi, Hitoshi Tsuchihashi, Akira Ishii
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    ABSTRACT: The aim of this review is to present the chemical aspects, pharmacology, acute toxicities, and metabolisms of α-pyrrolidinophenone derivatives, a new group of synthetic cathinones. Compared to other synthetic cathinones, α-pyrrolidinophenone derivatives have high lipophilicity due to the pyrrolidine ring substitution at the nitrogen atom, resulting in higher blood–brain barrier permeability. To date, some acute intoxication and fatal cases involving α-pyrrolidinophenone derivatives have been reported, and the symptoms induced by their high dosages are due to central nervous system and cardiovascular toxicities. Based on the previous metabolism studies, reduction of the β-ketone moiety to the corresponding alcohol metabolites and oxidation to the 2′′-oxo metabolites are the main metabolic pathways observed among α-pyrrolidinophenone derivatives. In addition to such pathways, specific metabolic pathways like hydroxylation followed by oxidation of the 4′-methyl group, O-demethylation of the 4′-methoxyl group, and demethylenation followed by O-methylation of the 3′,4′-methylenedioxy group can be observed for the corresponding ring-substituted compounds.
    Forensic Toxicology 01/2013; 32(1). · 5.76 Impact Factor
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    ABSTRACT: A liquid chromatography-electrospray ionization tandem mass spectrometry (LC-ESI-MS/MS) procedure was developed for the simultaneous determination of enantiomers of the prevalent designer drug 3,4-methylenedioxymethamphetamine (MDMA) and its phase I and phase II metabolites in urine with chiral derivatization. The analytes in urine were directly derivatized with chiral Marfey's reagent, N (α)- (5-fluoro-2,4-dinitrophenyl)-D-leucinamide, without extraction. The diastereomers of the N (α)-(2,4-dinitrophenyl)-D-leucinamide derivatives generated were determined by LC-MS/MS. Satisfactory chromatographic separation was achieved for the enantiomers of MDMA and its metabolites 3,4-methylenedioxyamphetamine, 4-hydroxy-3-methoxymethamphetamine (HMMA), HMMA glucuronide, and HMMA sulfate on a semimicro octadecylsilane column using linear gradient elution. With use of multiple reaction monitoring mode, the limits of detection of these analytes ranged from 0.01 to 0.03 μg/mL. Linear calibration curves were obtained for all enantiomers from 0.1 to 20 μg/mL in urine. The method showed sufficient reproducibility and quantitative ability. This is the first report of a simple LC-MS/MS-based analytical procedure with direct chiral derivatization in aqueous media that allows simultaneous enantiomeric determination of drugs and their metabolites, including glucuronide and sulfate derivatives.
    Analytical and Bioanalytical Chemistry 09/2012; 404(8):2427-35. · 3.66 Impact Factor
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    ABSTRACT: Transmesenteric hernias are internal hernias caused by a congenital defect in the mesentery. They are rare causes of intestinal obstruction, but most commonly affect the small bowel. We report an unexpected death of an infant with a bowel obstruction caused by a congenital mesenteric defect, which was undiagnosed despite visits to three different hospitals. Mesenteric defects are usually 2-3 cm in diameter. At autopsy, we found an oval, 14 × 7 cm congenital defect in the ileal mesentery through which the small bowel had herniated. Diagnosis of such defects remains difficult, even with currently available imaging techniques. Diagnosis is particularly difficult in infants who usually have nonspecific symptoms. Therefore, it is important that sudden unexpected deaths in children undergo full forensic evaluation to establish the precise cause of death. It is also important for forensic physicians to inform clinicians of the risk of such diseases, particularly in emergency situations.
    Legal Medicine 02/2012; 14(3):157-9. · 1.44 Impact Factor
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    ABSTRACT: Cathinone-derived designer drugs have recently grown to be popular as drugs of abuse. 3,4-Dimethylmethcathinone (DMMC) has recently been abused as one of the alternatives to controlled cathinones. In the present study, DMMC and its major metabolites, 3,4-dimethylcathinone (DMC), 1-(3,4-dimethylphenyl)-2-methylaminopropan-1-ol (β-OH-DMMC, diastereomers), and 2-amino-1-(3,4-dimethylphenyl)propan-1-ol (β-OH-DMC, diastereomers), have been identified and quantified in a DMMC user’s urine by gas chromatography–mass spectrometry and liquid chromatography–tandem mass spectrometry using newly synthesized authentic standards. Other putative metabolites including oxidative metabolites of the xylyl group and conjugated metabolites have also been detected in urine. The identified and putative phase I metabolites indicated that the metabolic pathways of DMMC include its reduction of the ketone group to the corresponding alcohols, N-demethylation to the primary amine, oxidation of the xylyl group to the corresponding alcohol and carboxylate forms, and combination of these steps. Concentrations of the identified metabolites were found to increase slightly after enzymatic hydrolysis, suggesting that these compounds are partially metabolized to the respective conjugates.
    Forensic Toxicology 01/2012; 31(1). · 5.76 Impact Factor
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    ABSTRACT: Cross-reactivities of 76 kinds of phenethylamine-type designer drugs and related compounds to the urine drug tests Instant-View ™ (IV) (the Methamphetamine (MA) test, the Amphetamine 300 test, and the MDMA test) have been investigated. An on-site urine test kit consisting of these three IV tests has been evaluated for the on-site screening of MA users, and the kit has been found to have satisfactory specificity for drug enforcement purposes by separately detecting both MA and its metabolite amphetamine. The cross-reactivity profiles of Emit(®) II Plus Amphetamines Assay, Emit(®) II Plus Ecstasy assay, and Emit(®) d.a.u.(®) Amphetamine Class assay have also been investigated and discussed.
    Forensic science international 12/2011; 217(1-3):174-81. · 2.10 Impact Factor
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    ABSTRACT: β-Keto derivatives of 3,4-methylenedioxyphenylalkylamines (bk-MDPAs), especially 2-methylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (methylone), 2-methylamino-1-(3,4-methylenedioxyphenyl)butan-1-one (bk-MBDB), and 2-ethylamino-1-(3,4-methylenedioxyphenyl)propan-1-one (bk-MDEA), are abused as substitutes for 3,4-methylenedioxyphenylalkylamines in some countries, causing increased social problems. With the widespread abuse of bk-MDPAs, the analysis of bk-MDPAs and their metabolites in human specimens is quite important in forensic and clinical toxicology. In this review, the metabolisms of bk-MDPAs and simultaneous analytical methods for bk-MDPAs and their metabolites by gas chromatography–mass spectrometry, liquid chromatography–mass spectrometry, and liquid chromatography–tandem mass spectrometry are presented. Keywordsβ-Keto-3,4-methylenedioxyphenylalkylamines–bk-MDPAs–Methylone–bk-MBDB–bk-MDEA–Designer drug
    Forensic Toxicology 07/2011; 29(2):73-84. · 5.76 Impact Factor
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    ABSTRACT: Matrix-assisted laser desorption ionization (MALDI)–time-of-flight (TOF) mass spectrometry (MS) was used for visual demonstration of methamphetamine (MA) incorporation into human hair. Longitudinal sections of human scalp hair shafts from chronic MA users were directly subjected to imaging MS. Numerous MA-positive spots with various intensities were observed in the specimens, which probably reflect habitual MA abuse and the different MA blood levels upon each administration. This imaging MS method for drugs in hair seems to give much more accurate chronological information on drug use, and clearer discrimination between deliberate drug use and passive exposure, using only a single hair shaft. This is the first report of imaging MS applied to forensic toxicology. This method is expected open a new field in analyses of drugs in hair. KeywordsHair analysis–Imaging MS–Mass microscopy–MALDI-TOF–Methamphetamine–Visual demonstration
    Forensic Toxicology 07/2011; 29(2):111-116. · 5.76 Impact Factor
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    ABSTRACT: Methamphetamine (MA) is an illicit psychostimulant, and its abuse has become an international public health problem. MA intoxication can cause life-threatening hyperthermia, renal and liver failure, cardiac arrhythmias, and neurological damage. To investigate the relationship between the underlying mechanism of such intoxication and metabolic networks, mass spectrometry-based metabolomics experiments were performed on Sprague-Dawley rats treated with MA at 10mgkg(-1)h(-1) for 4h. Using a combination of gas chromatography-time-of-flight mass spectrometry and capillary electrophoresis-tandem mass spectrometry, global and targeted analyses were performed on biological samples collected during 0-24 and 72-96h (for urine), and at 24 and 96h (for plasma) after the last drug administration. Body temperature and plasma biochemical parameters were also measured to detect abnormal reactions in neuronal and other several tissues. 5-Oxoproline, saccharic acid, uracil, 3-hydroxybutyrate (3-HB), adipic acid, glucose, glucose 6-phosphate, fructose 1,6-bisphosphate, and tricarboxylic acid (TCA) cycle intermediates, such as fumarate, were proposed as potential biomarkers related to MA-induced intoxications. In particular, the observation of decreased TCA cycle intermediates and 3-HB and increased glucose suggested that high doses of MA inhibit biogenic energy production by glycolysis, oxidative phosphorylation via the TCA cycle, and the beta-oxidation of fatty acids. These results may provide not only a clue to clarify the underlying mechanism of diverse intoxication effects, but also biological fluid-based diagnostic and forensic methods with which to objectively demonstrate intoxication without directly determining the drug.
    Toxicology 05/2011; 287(1-3):29-37. · 3.75 Impact Factor
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    ABSTRACT: A new approach is described for imaging mass spectrometry (IMS) of methamphetamine (MA) incorporated into human hair using matrix-assisted laser desorption/ionization (MALDI)-time-of-flight (TOF) and MALDI-Fourier transform ion cyclotron resonance (FTICR). A longitudinal section of a lengthwise manually-cut single human hair shaft from a chronic MA user was directly analyzed by MALDI-TOF-IMS after deposited with α-Cyano-4-hydroxycinnamic acid matrix. A barcode-like image, which was most probably generated with repeated intakes of MA, was for the first time obtained by monitoring MA-specific product ion in the selected reaction monitoring mode. Laser beam scan lengthwise-cut hair shafts gave only poor mass spectra of MA, probably due to the loss of MA and/or the thermal denaturation of hair. The identity of MA detected in hair was further confirmed by MALDI-FTICR mass spectrometry. A combination with ultra-high resolution mass spectrometry by FTICR provided indisputable identification of MA. The MALDI-FTICR-IMS of another hair shaft from the same MA user also provided a barcode-like image by monitoring the protonated molecule of MA with ultra-high resolution. The two barcode-like images exhibited a close resemblance. Thus, MALDI-IMS can offer a new perspective: 'imaging hair analyses for drugs'.
    Biological Mass Spectrometry 04/2011; 46(4):411-6. · 2.71 Impact Factor
  • Japanese Journal of Forensic Science and Technology 01/2011; 16(2):73-90.
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    ABSTRACT: 5-Methoxy-N,N-dialkyltryptamines are tryptamine derivatives that possess strong hallucinogenic effects. Because of their escalating popularity and potent physiological effects, an increasing number of acute poisoning cases have been reported in various countries. For their metabolism in humans, only a few studies have been reported. Thus, based on previous studies, the authors forecasted and synthesized authentic standards of their expected metabolites, which retained the structural characteristics of the parent drugs. Using these authentic standards, several urine specimens from abusers and rats were analyzed by gas chromatography mass spectrometry, high-performance liquid chromatography mass spectrometry, and high-performance liquid chromatography tandem mass spectrometry. The present study reveals that four metabolic pathways of great quantitative significance for 5-Methoxy-N,N-dialkyltryptamines to four characteristic metabolites, which retain structural characteristics identifiable with the parent compound, exist in humans and rats. The finding in the present study will be of great importance in the study on the metabolism of other psychotomimetic tryptamine-derived drugs of abuse and in forensic toxicologic analyses.
    Therapeutic drug monitoring 04/2010; 32(3):328-31. · 2.43 Impact Factor
  • Tooru Kamata, Munehiro Katagi, Hitoshi Tsuchihashi
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    ABSTRACT: Hallucinogenic tryptamine analogues, an important class of drugs of abuse, can be naturally occurring or chemically synthesized compounds. In Japan, psilocin and psilocybin (ingredients of “magic mushrooms”) and 5-methoxy-N,N-diisopropyltryptamine (5-MeO-DIPT; a synthetic tryptamine) seem to be particularly problematic due to their extensive abuse. This review is focused on human metabolism and forensic toxicological analyses of the above three tryptamine analogues. In humans, psilocybin is rapidly dephosphorylated to form psilocin, and most of the psilocin is eventually conjugated to form its glucuronide. On the other hand, 5-MeO-DIPT is mainly metabolized via O-demethylation, 6-hydroxylation, and N-deisopropylation, partly followed by conjugation to form their sulfates and glucuronides. Suitable hydrolysis should be, therefore, applied for sensitive and effective analysis of the metabolites. In analyzing psilocin and psilocybin by gas chromatography-mass spectrometry (GC-MS), derivatization is necessary for their discriminative identification. Although 5-MeO-DIPT and its three major metabolites can be analyzed by GC-MS without any derivatization, trimethylsilyl derivatization provides improvement of their peak shapes and intensities. In contrast to GC-MS, liquid chromatography-mass spectrometry and liquid chromatography-tandem mass spectrometry allow us not only to discriminate psilocin and psilocybin without derivatization, but also to directly analyze their conjugated metabolites.
    Forensic Toxicology 01/2010; 28(1):1-8. · 5.76 Impact Factor
  • Japanese Journal of Forensic Science and Technology 01/2010; 15(2):75-84.

Publication Stats

965 Citations
227.89 Total Impact Points


  • 2011–2014
    • Osaka Medical College
      • Department of Legal Medicine
      Takatuki, Ōsaka, Japan
  • 2004
    • Kansai Medical University
      • Department of Legal Medicine
      Moriguchi, Osaka-fu, Japan
  • 1991
    • Kinki University
      • Department of Pharmaceutical Science
      Ōsaka, Ōsaka, Japan