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Natsuki Ikematsu

Bio: Natsuki Ikematsu is an academic researcher from Fukuoka University. The author has contributed to research in topics: Subarachnoid hemorrhage & Solid-phase microextraction. The author has an hindex of 5, co-authored 21 publications receiving 80 citations.

Papers
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Journal ArticleDOI
TL;DR: Using a detection method that has been rarely utilized to analyze these types of compounds, gas chromatography with positive chemical ionization and tandem mass spectrometry (GC-PCI-MS/MS), 5 psychotropic compounds were detected in an actual forensic autopsy case.

20 citations

Journal ArticleDOI
TL;DR: Simple and efficient extraction methods have been developed for the screening of a wide array of drugs in postmortem autopsy specimens that could easily be incorporated into a forensic laboratory's daily routine for screening many different compounds from postmortem samples.

17 citations

Journal ArticleDOI
TL;DR: This is the first instance of suvorexant being quantitated from actual autopsy cases and it is likely that this compound will be encountered more often by the forensic toxicology community going forward.
Abstract: Suvorexant (Belsomra®) is a relatively new insomnia medication that has been available in USA and Japan since 2014. It is a dual orexin receptor antagonist that promotes sleep by inhibiting the binding of orexin neurons to the OX1R and OX2R receptors. In this report, we describe the detection and quantitation of suvorexant from the postmortem specimens of three separate autopsy cases handled by our department. Suvorexant was identified by fast gas chromatography/mass spectrometry during routine screening, and quantitated by a fully validated liquid chromatography-tandem mass spectroscopy method. Quantitation was achieved by positive electrospray ionization in the selected reaction monitoring mode. Monitored transitions were m/z 451 > 186 for quantitation and m/z 451 > 104 for qualification. To our knowledge, this is the first instance of suvorexant being quantitated from actual autopsy cases. It is likely that this compound will be encountered more often by the forensic toxicology community going forward.

9 citations

Journal ArticleDOI
TL;DR: In this article, the distribution of p-cresolin in the blood, urine, lungs, liver, and kidneys of hemodialysis patients from forensic autopsy cases was investigated.
Abstract: Background p-Cresol concentrations are high in the blood of hemodialysis (HD) patients. However, its organ distribution has not yet been investigated in detail. We herein report the distribution of p-cresolin HD patients from forensic autopsy cases. Methods p-Cresol was measured in the blood, urine, lungs, liver, and kidneys from 4 HD and 4 non-HD cases. Samples were extracted with p-cresol-d8 (internal standard), derivatized,and injected on the GC-MS. Results and discussion The total urinary p-cresol/Cr was 79.73 ng/ml in HD cases,which was 16-fold higher than that in non-HD cases. p-Cresol in the blood and kidneys were 30-fold higher or more at 11.92 and 13.08 µg/mL(g), respectively. p-Cresol in the liver and lungs were approximately 20-fold higher at 4.82 and 9.99 µg/g, respectively. p-Cresol was markedly increased in not only the blood, but also the urine and organs of HD cases. The distribution of p-cresol in the blood, urine, and organs differed between HD and non-HD cases. In HD cases, the percentages of conjugated (C) and protein-bound conjugated (PC) urinary p-cresol were 57 and 41%, respectively. C and PC p-cresol was 66% and 25% in the kidneys, respectively, and similar results were obtained in the lungs. J. Med. Invest. 66 : 81-85, February, 2019.

8 citations

Journal ArticleDOI
TL;DR: Investigation of the frequency of the p.R1193Q substitution in more than 4000 genomic DNA samples from 34 Asian, European, and African populations using TaqMan and/or APLP (amplified product length polymorphism) assays demonstrated that thep.R 1193 Q substitution is characteristic of Asian populations.

8 citations


Cited by
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Journal ArticleDOI
01 Feb 1963-Nature
TL;DR: Experimental NeurologyBy Prof. Paul Glees.
Abstract: Experimental Neurology By Prof Paul Glees Pp xii + 532 (Oxford: Clarendon Press; London: Oxford University Press, 1961) 75s net

1,559 citations

Journal ArticleDOI
TL;DR: Various microextraction methods are reviewed, which include solid-based microextracted, such as solid-phase microextractions, microext extraction by packed sorbent and stir-bar sorptive extraction, and liquid-basedmicroextraction, as well as their applications to forensic toxicology analysis.
Abstract: Sample preparation is a critical step in forensic analytical toxicology. Different extraction techniques are employed with the goals of removing interferences from the biological samples, such as blood, tissues and hair, reducing matrix effects and concentrating the target analytes, among others. With the objective of developing faster and more ecological procedures, microextraction techniques have been expanding their applications in the recent years. This article reviews various microextraction methods, which include solid-based microextraction, such as solid-phase microextraction, microextraction by packed sorbent and stir-bar sorptive extraction, and liquid-based microextraction, such as single drop/hollow fiber-based liquid-phase microextraction and dispersive liquid-liquid microextraction, as well as their applications to forensic toxicology analysis. The development trend in future microextraction sample preparation is discussed.

48 citations

Journal ArticleDOI
TL;DR: Its dynamic regulation, the nanoscale architecture of its synaptic lattice, and the implications of gephyrin dysfunction for neuropathologic conditions, such as Alzheimer’s disease and epilepsy are discussed.
Abstract: Scaffolding proteins underlying postsynaptic membrane specializations are important structural and functional components of both excitatory and inhibitory synapses. At inhibitory synapses, gephyrin was identified as anchoring protein. Gephyrin self-assembles into a complex flat submembranous lattice that slows the lateral mobility of glycine and GABAA receptors, thus allowing for their clustering at postsynaptic sites. The structure and stability of the gephyrin lattice is dynamically regulated by posttranslational modifications and interactions with binding partners. As gephyrin is the core scaffolding protein for virtually all inhibitory synapses, any changes in the structure or stability of its lattice can profoundly change the packing density of inhibitory receptors and, therefore, alter inhibitory drive. Intriguingly, gephyrin plays a completely independent role in non-neuronal cells, where it facilitates two steps in the biosynthesis of the molybdenum cofactor. In this review, we provide an overview of the role of gephyrin at inhibitory synapses and beyond. We discuss its dynamic regulation, the nanoscale architecture of its synaptic lattice, and the implications of gephyrin dysfunction for neuropathologic conditions, such as Alzheimer's disease and epilepsy.

38 citations

Journal ArticleDOI
TL;DR: It is demonstrated that cold electron ionization produced enhanced molecular ion intensity for most of the bath salts considered, as well as more informative fragmentation, and MS/MS can offer improved confidence in synthetic cathinone identification even in cases where the relative intensity of the molecular ion is very low in MS spectra.

34 citations

Journal ArticleDOI
TL;DR: The purpose of this review is to describe the basic genetic and pathophysiological findings of the IPAS, particularly LQTS and Brugada syndrome, and to outline a rational approach to genetic testing, management, and family screening.

30 citations