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In forensic toxicology studies, drug concentrations must be estimated by the analytical data of formalin-fixed tissues if fresh or frozen tissue specimens are not available. We wished to investigate the stability and time-course of metabolism/degradation of drugs in formalin-fixed tissues using porcine liver homogenates (PLHs) instead of human tissue. Ten psychotropic drugs (amitriptyline, brotizolam, diazepam, diphenhydramine, estazolam, etizolam, levomepromazine, paroxetine, quetiapine and triazolam) were added to PLHs. After the PLHs had been fixed with neutral buffered formalin at room temperature, the concentrations of the drugs in the PLHs were determined by liquid chromatography-tandem mass spectrometry after 3 days, 1 week, 2 weeks, 4 weeks, 2 months, 4 months and 6 months. After 6 months, the residual ratio of amitriptyline, diphenhydramine and quetiapine was 80 %-95 %; that of diazepam, paroxetine and triazolam was 10 %-45 %; and that of brotizolam, etizolam and levomepromazine was 1 %-5 %. Estazolam was not detected from the first day of formalin fixation. These data suggest that the concentrations of drugs in PLHs measured after formalin fixation decreased to varying degrees compared with their initial concentrations. These time-dependent changes in drug concentration were due to degradation during preservation in formalin solution and metabolism by hepatic microsomal enzymes., Competing Interests: Declaration of Competing Interest There are no financial or other relationships that could lead to a conflict of interest., (Copyright © 2019 Elsevier B.V. All rights reserved.)

The case of a suicide of a 32-year-old female using an electric circular saw is herein described. The decedent was suffering from depression and was found dead in her room. Beside her right hand was lying a circular saw, which was not running. The autopsy revealed a large gaping wound measuring 15.5 cm in length on the right side of her neck. The right external carotid artery, the right internal jugular vein, and the right internal carotid artery were cut and the injury reached to the cervical vertebra. Therefore, the cause of death was exsanguination. An individual who commits suicide with an electric saw, such as a chain saw, band saw, and circular saw is rare; in particular females rarely select this method as the means of suicide. However, we herein report the case of a female patient with a psychiatric disease who successfully committed suicide with a circular saw.

Adipocere formation is well known as a later post-mortem change. We experienced a female victim who had been sealed up in a clothes box for approximately 4 years. We collected several subcutaneous fats as well as visceral fats from the victim to investigate adipocere formation. Fresh subcutaneous fats of one female and five male victims who suddenly died were used as the control. These samples were homogenized and the lipids were extracted with chloroform and methanol followed by injection into gas chromatography-mass spectrometry and gas chromatography. We detected a hydroxy fatty acid in the fat of the case, but not in the controls. Using standard synthetic hydroxy fatty acid, the lipid extract component was identified as 10-hydroxyoctadecanoic acid (10-OH 18:0) and this concentration was quantified. Consequently we confirmed that adipocere was formed much slowly in dry concealment. In addition, the fatty acid composition was compared with the control. Most of the linoleic acid (18:2) disappeared and a peak developed instead. Using standard synthetic fatty acid, this peak was identified as cis-12-octadecenoic acid (cis-12-18:1). This suggests that linoleic acid is hydrogenated to cis-12-octadecenoic acid in the process of adipocere formation.

Diquat can be extracted with 1-butanol from high pH solution in the presence of several moderate reductants. The red colored reduced compound of diquat in water turns to a purple compound in 1-butanol. The absorption of the purple compound is 0.105 at 383 nm and 0.119 at 520 nm in 1 microgram diquat/ml 1-butanol. The latter value is a little higher than that of the red compound at 495 nm in water. The purple compound is much more stable than the red compound in water. More than 80% of 10 ppm diquat added can be extracted from serum, blood, tissues, urine and some drinks. The extraction with 1-butanol is useful for concentration of diquat contained in large volume. The lower limit of detection is 0.1 microgram/ml 1-butanol. Paraquat is insoluble in 1-butanol under the same condition. Therefore, this method is applicable for the determination of diquat when paraquat is also contained in the solution.

A very simple and sensitive method for quantitative measurement of paraquat in plasma, urine and some drinks is described. The paraquat radical formed by its reduction can be detected by electron spin resonance spectroscopy (ESR) at room temperature without clean-up or concentration process of samples. The sensitivity limit is 0.1 microgram paraquat/ml and the required amount of sample is 100 microliter. The time needed for the measurement is within 10 min.