Tomomi Ishida

Pattern of poisoning in Japan: selection of drugs and poisons for systematic toxicological analysis

Patterns of poisoning are known to be different in different countries, because of the local environmental, cultural, and religious situations. Therefore, in Japan, it is important to know the pattern of poisoning in our own country and to prepare for every poisoning case by establishing an efficient systematic toxicological analysis system in forensic practice. We conducted a retrospective study of the kinds of compounds causing poisonings and the frequency of their use based on two series of reports dealing with poisoning cases in Japan prepared by the National Research Institute of Police Science and the Japanese Society of Legal Medicine for 2003 to 2006. From these reports, 459 and 177 compounds, respectively, were extracted as poisonous compounds over the study period. After data analysis, we selected 314 drugs and poisons as important target compounds for systematic drug analysis in Japan; they included 36 volatile compounds, 14 abused drugs, 170 medical drugs, 60 pesticides, 13 natural toxins, and 21 others. This is the first study to show the toxic drugs and poisons to be analyzed in Japan based on frequency of use, and as such the list will be useful in establishing the most efficient screening system in forensic practice.

Construction of calibration-locking databases for rapid and reliable drug screening by gas chromatography-mass spectrometry

Unique calibration-locking databases were constructed for rapid and semiquantitative drug screening by gas chromatography-mass spectrometry (GCMS). In addition to the free-drug database of 127 drugs, a drug database with acetylating reagents was constructed to increase the number of detectable compounds in the analysis by GC-MS; 156 drugs, including 30 drugs of abuse, 42 hypnotics and their metabolites, 18 antipsychotic drugs, 15 antidepressants, and 12 antipyretic analgesic agents, were registered with parameters, such as the mass spectrum, retention time, qualifier ion/target ion percentage, and calibration curve using the novel GC-MS software NAGINATA. Diazepam-d5 was used as internal standard for construction of each calibration curve in the range of 0.01–5.0 μg/ml for most drugs. We examined the applicability of the constructed database to analyzing whole blood samples spiked with 40 drugs most commonly encountered in toxicological cases in Japan. The drugs in blood were extracted using enhanced polymer columns (Focus), subjected to GC-MS after incubation with acetylating reagents, and screened by the drug database. Among the 40 drugs examined, 38 and 30 drugs were successfully identifi ed at the level of 1 and 0.1 μg/ml, respectively, without using standard compounds. The time required for data analysis was less than 1 min, and semiquantitative data were also obtained simultaneously. Because new drugs and metabolites can easily be added to the databases, we can recommend them as useful tools in clinical and forensic toxicological screening.

Rapid and quantitative screening method for 43 benzodiazepines and their metabolites, zolpidem and zopiclone in human plasma by liquid chromatography/mass spectrometry with a small particle column

Benzodiazepines and their pharmacologically related drugs, zolpidem and zopiclone are widely prescribed as safe drugs, but these drugs are also abused in cases of crime, suicide and drug-facilitated sexual assault. We developed a rapid and quantitative screening method for 43 benzodiazepines, their metabolites, zolpidem and zopiclone in human plasma by liquid chromatography/mass spectrometry with a small particle column. All drugs were successfully separated within 12 min using combined scan and selected ion recording (SIR) mode. The calibration curves of most drugs were linear in the concentration range 0.5-250 ng/mL with correlation coefficients exceeding 0.99. Within-day precisions (RSD, %) of this method were 1.8-15.6% (10 ng/mL) and 0.6-10.1% (100 ng/mL) and between-day precisions (RSD, %) were 1.6-16.9% (10 ng/mL) and 0.6-16.7% (100 ng/mL). The average recoveries were 70.1% (10 ng/mL) and 87.1% (100 ng/mL). The limit of detection ranged from 0.2 to 8.0 ng/mL in 37 drugs and was below 0.2 ng/mL in 6 drugs. The established method is sensitive and rapid, thus it should be useful in forensic and clinical toxicological analyses.

Vulnerability of experimentally induced fatty liver to heat stress in rats

BackgroundThe aim of this study was to confirm the vulnerability of fatty liver to heat stress using fatty liver rats from the viewpoint of the induction of apoptosis.MethodsWe exposed rats with and without a fatty liver to heat stress and then looked for apoptotic cells within the liver tissue using two apoptosis detection kits. We also determined the mRNA expression of heat shock protein (HSP) 70, caspase-3, bcl-2, and bax using a quantitative reverse transcription-polymerase chain reaction method.ResultsFollowing heat stress, apoptosis was strongly visible in the fatty liver comparing with that noted in the normal liver. The expression of HSP70 was increased following heat stress in both livers, but the volume of its expression was significantly less in the fatty liver than in the normal liver. The ratio of bcl-2/bax expression tended to increase in the normal liver but decrease in the fatty liver following heat stress. Caspase-3 demonstrated no significant change following heat stress in both livers.ConclusionsThe detection of apoptosis, together with changes in the mRNA expression of HSP70 and the expression ratio bcl-2/bax mRNA may indicate vulnerability of a fatty liver to heat stress and may support the hypothesis that morphologic change is induced in a fatty liver by exposure to heat stress. These results suggest that fatty liver may be more vulnerable to heat stress than normal liver.

A Case of Poisoning in a Man who Drank a Nutrition Supplement Containing Methomyl, A Carbamate Pesticide

A 50-year-old man was admitted to the emergency room complaining oppression on his chest, sweating and vomiting. He had drunk a 30 ml volume nutrition supplement 60 minutes before. As myosis and decrease of serum choline esterase activity were observed on admission examination, poisoning was suspected and toxicological analyses were carried out on the heeltap of the drink. Drug screening by gas chromatography-mass spectrometry (GC/MS) revealed the presence of methomyl and the concentration of methomyl in the heeltap determined by liquid chromatography was 2.1 mg/ml. Methomyl concentrations in the serum and urine were determined after converting methomyl to its oxime form followed by derivatization and GC/MS. Methomyl concentration in the serum collected 6 hours after ingestion was 0.63 microg/ml, and that in the urine collected 7-20 hours after ingestion was 0.10 microg/ml. Based on these values and reported data, the amount of methomyl contaminated to the drink was considered to be a toxic dose.

Disposition and metabolism of [14C]lemborexant, a novel dual orexin receptor antagonist, in rats and monkeys

Abstract The disposition and metabolism of lemborexant, a novel dual orexin receptor antagonist currently under development as a therapeutic agent for insomnia disorder, were evaluated after a single oral administration of [14C]lemborexant in Sprague-Dawley rats (10 mg/kg) and cynomolgus monkeys (3 mg/kg). In both species, [14C]lemborexant was rapidly absorbed: radioactivity concentration in blood peaked at 0.83–1.8 h, and decreased with elimination half-life of 110 h. The radioactivity administered was excreted primarily into faeces, with relatively little excreted into urine. Lemborexant was not detected in bile, urine or faeces, indicating that lemborexant administered orally was completely absorbed from the gastrointestinal tract and that the main elimination pathway was metabolism in both species. In rats, lemborexant was found to be minor in plasma (≤5.2% of total radioactivity), and M9 (hydroxylated form) was the major circulating metabolite. In monkeys, the major circulating components were lemborexant, M4 (N-oxide metabolite), M13 (di-oxidised form), M14 (di-oxidised form) and M16 (glucuronide of mono-oxidised form). In both species, lemborexant was metabolised to various metabolites by multiple pathways, the primary of which was oxidation of the dimethylpyrimidine or fluorophenyl moiety.