[Creation of 3D Stereo and MPR Color Anatomical Charts in the Hepatic Segments].

We used the Voronoi diagram of a computed tomography (CT) application (i.e., CT liver volume measurement) to depict the liver area, and we obtained depictions of the hepatic segments as a three-dimensional (3D) image based on clinical data; this information can be used for the patient's education and for surgical planning. The hepatic segments use the inter-relationships among the eight subsegments illustrated by Couinaud, those indicated by the portal veins and those provided by hepatic veins. The liver has dual portal and arterial innervation, with the thick portal vein intertwined with thin arteries similar to the intertwining of ivy plants. Couinaud divided the liver into eight segments (S1 to S8) based on portal vein casts. The Voronoi diagram estimates the dominant region of the portal vein, divides the liver into segments, and produces 3D images and multiplanar reconstruction (MPR) images in color. To support understanding of Couinaud's eight hepatic segments (which are explained only in the illustration of the frontal view of the liver), using 3D images created by the Voronoi diagram, we created 3D stereo color anatomical charts of the liver that Couinaud's eight hepatic segments can be confirmed from multiple directions. In addition, we created the MPR color anatomical charts of the liver (S1 to S8) that can be confirmed by color from three directions: axial images, coronal images, and sagittal images in the same way. We converted the data of this anatomical chart into an electronic file that provides a tool that can be easily used in radiological examinations, and we were able to make improvements based on requests from users.

Development of two fully automated quick, easy, cheap, effective, rugged, and safe pretreatment methods for the extraction of psychotropic drugs from whole blood samples.

Quick, easy, cheap, effective, rugged, and safe extraction strategies are becoming increasingly adopted in various analytical fields to determine drugs in biological specimens. In the present study, we developed two fully automated quick, easy, cheap, effective, rugged, and safe extraction methods based on acetonitrile salting-out assisted liquid-liquid extraction (method 1) and acetonitrile salting-out assisted liquid-liquid extraction followed by dispersive solid-phase extraction (method 2) using a commercially available automated liquid-liquid extraction system. We applied these methods to the extraction of 14 psychotropic drugs (11 benzodiazepines and carbamazepine, quetiapine, and zolpidem) from whole blood samples. Both methods prior to liquid chromatography-tandem mass spectrometry analysis exhibited high linearity of calibration curves (correlation coefficients, > 0.9997), ppt level detection sensitivities, and satisfactory precisions (< 8.6% relative standard deviation), accuracies (within ± 16% relative error), and matrix effects (81-111%). Method 1 provided higher recovery rates (80-91%) than method 2 (72-86%), whereas method 2 provided higher detection sensitivities (limits of detection, 0.003-0.094 ng/mL) than method 1 (0.025-0.47 ng/mL) owing to the effectiveness of its dispersive solid-phase extraction cleanup step. These fully automated extraction methods realize reliable, labor-saving, user-friendly, and hygienic extraction of target analytes from whole blood samples.

Human and rat microsomal metabolites of N-tert-butoxycarbonylmethamphetamine and its urinary metabolites in rat.

PURPOSE: N-tert-Butoxycarbonylmethamphetamine (BocMA), a masked derivative of methamphetamine (MA), converts into MA under acidic condition and potentially acts as a precursor to MA following ingestion. To investigate the metabolism and excretion of BocMA, metabolism tests were conducted using human liver microsomes (HLM), rat liver microsomes (RLM) and rat. METHODS: BocMA metabolites were analyzed after 1000-ng/mL BocMA incubation with microsomes for 3, 8, 13, 20, 30, and 60 min. Rats were administered intraperitoneal injections (20 mg/kg) of BocMA and their urine was collected in intervals for 72 h. Metabolites were detected by liquid chromatography-tandem mass spectrometry with five authentic standards. RESULTS: Several metabolites including 4-hydroxy-BocMA, N-tert-butoxycarbonylephedrine and N-tert-butoxycarbonyl-cathinone were detected for HLM and RLM. In the administration test, three glucuronides of hydroxylated metabolites were detected. The total recovery values of BocMA and the metabolites during the first 72 h accounted for only 0.3% of the administered dose. Throughout the microsomal and administration experiments, MAs were not detected. CONCLUSION: Hydroxylation, carbonylation and N-demethylation were proposed as metabolic pathways. However, BocMA and phase I metabolites were hardly detected in urine. This study provides useful information to interpret the possibility of BocMA intake as the cause of MA detection in biological sample.

Easily Operable Quantification Method of 21 Plant-Derived Alkaloids in Human Serum by Automatic Sample Preparation and Liquid Chromatography-Tandem Mass Spectrometry.

In this study, we developed an easily operable quantification method for 21 plant-derived alkaloids in human serum by automatic sample preparation and liquid chromatography-tandem mass spectrometry. We designed to perform parallel sample preparation by a developed apparatus, which increased sample throughput. We conducted an automatic sample preparation through de-proteinization with 0.1% formic acid in methanol and achieved recovery rates of 89-107% (2.0-14% RSD) for all targeted analytes, demonstrating its high repeatability. The method validation results were satisfactory as follows: the linearity (r 2) of each calibration curve ranged from 0.978 to 1.000; the inter- and intra-day accuracies were 89.0-125% and 82.1-110%, respectively; the inter- and intra-day precisions were below 13% and 10%, respectively. Additionally, the lower limits of detection and quantification were 0.0044-0.047 and 0.013-0.14 ng/mL, respectively. Finally, the developed method was applied to pseudo-protoveratrine A poisoning serum and pseudo-colchicine poisoning serum, which were prepared by diluting acute-poisoning mice serum with human serum. Our method successfully quantitated protoveratrine A (0.15-0.25 ng/mL) and colchicine (4.8-6.0 ng/mL). Thus, our method is essential for prompt clinical treatment and critical care on patient in acute intoxication cases caused by plant-derived alkaloids. Supplementary Information: The online version contains supplementary material available at 10.1007/s10337-022-04212-5.

Dynamic Cloth Manipulation Considering Variable Stiffness and Material Change Using Deep Predictive Model With Parametric Bias.

Dynamic manipulation of flexible objects such as fabric, which is difficult to modelize, is one of the major challenges in robotics. With the development of deep learning, we are beginning to see results in simulations and some actual robots, but there are still many problems that have not yet been tackled. Humans can move their arms at high speed using their flexible bodies skillfully, and even when the material to be manipulated changes, they can manipulate the material after moving it several times and understanding its characteristics. Therefore, in this research, we focus on the following two points: (1) body control using a variable stiffness mechanism for more dynamic manipulation, and (2) response to changes in the material of the manipulated object using parametric bias. By incorporating these two approaches into a deep predictive model, we show through simulation and actual robot experiments that Musashi-W, a musculoskeletal humanoid with a variable stiffness mechanism, can dynamically manipulate cloth while detecting changes in the physical properties of the manipulated object.

[Creation of a Stereo-paired Bone Anatomical Chart Using Human Bone Specimens for X-ray Anatomical Education Part III: Addition of Anaglyph Three-dimensional Images for Those Who Hardly See Stereo-paired Photographs with the Naked Eye].

We published a report entitled "Creation of a stereo-paired bone anatomical chart using human bone specimen for radiation education" in this journal in order to accurately understand the surface structure and three-dimensional structure of bones, and assist in bone image interpretation. However, some people cannot see stereoscopically with the naked eye. Therefore, we created anaglyph three-dimensional (3D) images from stereo-paired images of the stereo X-ray anatomical chart of the bone specimen. The anaglyph of the bone surface and X-ray images facilitates stereoscopic viewing with red-blue 3D glasses. The stereo X-ray anatomical chart of the bone specimen with anaglyph 3D images was converted into an electronic data file in the same manner as the stereo X-ray anatomical chart of the bone specimen, which can be easily used in any radiological examination rooms or at home through an electronic medium. We made it possible to perform correlative stereoscopic observations of the bone surface and X-ray images using red-blue 3D glasses.

[Creation of Bone X-ray Radiography Manual Using Human Bone Specimens for Bone X-ray Radiography Education].

Senior radiological technologists have made various improvements and have supported the clinical and educational fields by explaining bone X-ray radiography to students and junior radiological technologists to understand the procedure using illustrations, X-ray images, and photographs in a way that corresponds to the design software available for that era. Because human bone specimens are only available in the anatomy laboratory of medical schools, they could not be used for the explanation of bone X-ray radiography until now. Therefore, we have developed a bone X-ray radiography manual using bone specimens for the bone X-ray radiography education, which helps students to understand the procedure of bone X-ray radiography. Previous bone X-ray radiography manuals had not been illustrated by bone specimens and bone specimen X-ray images, but this bone X-ray radiography manual using bone specimens has made it possible to understand the surface morphology of bone specimens and X-ray images of them. In addition, the data of bone X-ray radiography using this bone specimen were made into an electronic file, which can be easily used at the place of radiological examination or at home through electronic media.

[Creation of Stereo-paired Color Vascular Anatomical Charts Using 3-dimentional Images].

Three-dimensional (3D) images of blood vessels in the human body, which are acquired by X-ray computed tomography (CT) and cone-beam CT of Angiography devices, are widely used in medical diagnosis and treatment. Using the 3DCT images of blood vessels, we created stereo-paired color vascular anatomical charts for better understanding of vascular anatomy in clinical settings, patient explanations, and student education. Since it is difficult to distinguish branches of blood vessels that show three-dimensionally complicated running such as cerebral blood vessels, we made it easier to identify them anatomically by color-coding each branch of the blood vessel. Also, by using stereo-paired images, we can see the three-dimensional blood vessel running. In the past anatomical books and vascular anatomy atlas, there was no anatomical chart of the whole body blood vessels that could be color-coded and stereoscopically viewed. We have made it possible to identify blood vessels by the stereoscopic vision of the blood vessels using this stereo-paired color anatomical chart. In addition, this vascular anatomical chart can be additionally revised according to the needs of the clinical and educational settings to be used, and the data can be converted into an electronic file so that it can be easily used in the field of radiological examination or at home through electronic media.

[Creation of a Stereo-paired Bone Anatomical Chart Using Human Bone Specimens for X-ray Anatomical Education Part II: Addition of Stereo-paired X-ray Bone Images to the Anatomical Chart].

In a previous issue of this journal, we published a report entitled "Creation of Stereo-paired Bone Anatomical Charts Using Human Bone Specimens for Radiation Education" To understand how the bone specimen is visualized as an X-ray image, we newly created a bone specimen stereo-paired X-ray anatomical chart by adding the X-ray images of the same bone specimen. When a bone is X-rayed, the surface structure and internal structure of the bone are visualized as a composite image of the difference in X-ray absorption, and each bone becomes a unique X-ray image. Therefore, we took stereo-paired X-ray images of the bone specimens by the same method as the stereo-paired anatomical chart of the bone specimens. Then, we arranged the stereo-paired X-ray images and surface images of the same bone specimen in the one sheet to be readily compared. Similar to the previous bone specimen anatomical charts, these data of X-ray image anatomical chart were also made into an electronic file, so that we can do the three-dimensional observation of bone X-ray images even at the place of radiological examination or at home through electronic media. Until now, none of the specialized anatomy books and pictorial books are available for stereoscopic viewing of bone specimens and bone X-ray images. However, this stereo-paired X-ray image anatomical chart enabled us to learn accurate three-dimensionalization of bones by comparing the bone surface morphology and bone X-ray images.

Incorporation of Methoxyphenamine into Hair in Early Stage after Intake.

In order to investigate the incorporation behavior of drugs into hair in early stage (within 24 h) after intake, time-course changes in drug distribution in black hair were carefully analyzed after a single oral administration of methoxyphenamine (MOP), a non-regulated analog of methamphetamine. Single-hair specimens collected by plucking with the roots intact at appropriate intervals post-intake were each divided into 1-mm segments from the proximal end, and MOP in each segment was determined by a validated liquid chromatography-tandem mass spectrometry procedure. At 10 min after intake, MOP was not detected in any of the segments. MOP became detectable 30 min after intake in the hair bulb (0-1-mm segment from the proximal end) and 1 h after intake in the upper dermis zone (1-2-mm to 4-5-mm segments). The amount of MOP in the hair bulb increased rapidly over 3 h after intake and reached a maximum concentration of ∼100-900 pg/1-mm single hair (11-95 ng/mg) around 3-10 h after intake, whereas that in the upper dermis zone increased at a more gradual pace over 24 h and reached a plateau at ∼30-100 pg/1-mm hair (3-11 ng/mg). These differences can be attributed to the different incorporation mechanisms of the drug. Results from this study can further elucidate the drug incorporation mechanism, which is crucial for accurately interpreting results in hair analyses. Our findings also suggest that hair drug analysis with special attention to the hair root can serve as a useful complementary approach to urine- and blood-based testing in the field of forensic toxicology.

[Creation of Stereo-paired Bone Anatomical Charts Using Human Bone Specimens for Radiation Education].

In radiological examinations of patients, we often take stacked images and three-dimensional (3D) images of human bone radiological images such as X-ray images and CT images. In general, learning of bone structure using specialized anatomy books is currently performed at medical radiological technologist education facilities. In the anatomy education of the medical school, in order to understand the structure of human and the individual bone shapes in detail, a real human bone specimen is used to gain knowledge of skeleton, bone shape, bone name and bone function. But it is actually difficult for a radiological technologist to obtain such learning opportunities. Therefore, we had to depend on two-dimensional information from an anatomical atlas so far. Therefore, as a method to solve this, we devised this stereo-paired bone anatomical chart by stereoscopic photography of a real human bone specimen that is available only in the anatomy laboratory. In classical anatomy textbooks, there are no figures that enable us to view 3D structures of human bones. Our stereo-paired bone anatomical charts make it possible to observe accurate bone structures three-dimensionally. In addition, we saved the data as a PDF file and uploaded to an internet server so that we can freely download and readily observe 3D images of human bones at all times and all places with a tablet or a PC monitor.

[Creation of Stereo Color Anatomical Charts Showing Nerve Fibers in the Cerebral Lobe and Gyrus of the Brain for Use in the MR Examination].

In anatomical charts in conventional books, the pathways of nerve fibers are drawn in illustrations. Conversely, with diffusion tensor tractography (DTT), we can visually understand the trajectory of nerve fibers through color. We created a stereo color anatomical chart of the nerve fibers that can be used for magnetic resonance (MR) examination to diagnose the pathway of nerve fibers and that can be used to explain the results of MR examination to visually understand how nerve fiber information is transmitted from the frontal lobe, parietal lobe, occipital lobe, temporal lobe, cerebellar lobe, and cerebral cortex.

High Spatial-Resolution Matrix-Assisted Laser Desorption/Ionization-Ion Trap-Time-of-Flight Tandem Mass Spectrometry Imaging for Depicting Longitudinal and Transverse Distribution of Drugs Incorporated into Hair.

This study aims to achieve high spatial-resolution tandem mass spectrometry (MS/MS) imaging for depicting longitudinal and transverse distribution of drugs in hair, which can provide indispensable information for the proper interpretation of hair test results, including the mechanism of drug incorporation into hair. Two types of hair samples were obtained and analyzed: User's Hair, sampled from a volunteer who took an over-the-counter medicine containing methoxyphenamine (MOP), a nonregulated analogue of methamphetamine; and Soaked Hair, prepared by soaking blank hair in MOP solution. Longitudinal and transverse-sectioning of single hair shafts was accomplished by freeze-sectioning using customized microtomes. Vapor deposition of α-cyano-4-hydroxycinnamic acid provided the finest matrix layer (resolution <1 µm, 0.7-µm thickness), although it provided less effective ionization of MOP compared to aerosol spraying or a combination of both. Matrix-assisted laser desorption/ionization (MALDI)-ion trap (IT)-time-of-flight (TOF) MS/MS permitted the imaging of trace-level MOP in hair with a MS/MS window setting of ±0.02 Da and a spatial resolution setting at 5 or 10 µm. For Soaked Hair, localization of MOP in the peripheral part was clearly depicted, but no such biased distribution was observed in the transverse sections of User's Hair. MOP-positive bands generated corresponding to the time periods of MOP intake could be observed on the longitudinal sections of User's Hair. This method can provide forensically crucial information regarding hair analysis for drugs: drug incorporation mechanism into hair, discrimination of undesired surface contamination from endogenous incorporation of ingested drugs, and precise elucidation of drug-use history.

Effects of lipophilicity and functional groups of synthetic cannabinoids on their blood concentrations and urinary excretion.

The influence of lipophilicity and functional groups of synthetic cannabinoids (SCs) on their blood concentrations and urinary excretion has been studied by analyzing blood and urine specimens sampled from drivers who were involved in a car crashes under the influence of SCs. A total of 58 specimens (26 urine and 31 blood specimens), sampled within 13h of the occurrence, were analyzed by liquid chromatography-tandem mass spectrometry. Fifteen SCs were detected in those specimens; the SCs detected were categorized as follows: Class 1, Naphthoyl/Benzoyl indole (EAM2201 and three other analogs); Class 2, Indole-3-carboxylate/carboxamide containing naphthol/quinol (5F-PB-22 and four other analogs); and Class 3, Indazole-3-carboxamide containing valine/tert-leucine derivative (5F-AMB and five other analogs). The calculated lipophilicity index log P, the octanol/water participation coefficient, of those SCs in Classes 1, 2, and 3 ranged between 5.01-8.14, 5.80-6.74 and 2.29-3.81, respectively. Class 3 SCs were detectable in 12 out of 13 urine specimens, but those in Classes 1 and 2 were not detected in urine. Our analytical results indicated that the boundary line for their detectability in urine lies between log P 4 and 5. The blood concentrations of Class 3 SCs varied widely (0.0036-31ng/ml) depending on their log P, while much smaller variation was observed among those in Class 2 (0.10-5.0ng/ml).

Incorporation of zolpidem and methoxyphenamine into white hair strands after single administrations: Influence of hair pigmentation on drug incorporation.

In order to investigate the influence of pigmentation on the incorporation of drugs into hair, time-course changes in drug distribution along non-pigmented (white) hairs as well as pigmented (black) hairs plucked from the same subject was observed following single administrations of two basic drugs with different properties, zolpidem and methoxyphenamine. These drugs in 1-mm sections of single hair specimens were each determined by a liquid chromatography-tandem mass spectrometric procedure. During the early stage (12-36 h) after intake, for black hairs, both drugs were detected over the entire area of hair root (4-5 mm in length), in which notable concentration of these drugs in the hair bulb (0-1-mm segment from the bottom of hair root, Region 1) and lower concentrations in the upper dermis zone (1-2-mm to 3-4-mm or to 4-5-mm segments, Region 2) were commonly observed. Meanwhile, for white hairs, high drug concentrations in Region 1 as detected in black hairs were not observed although only small amounts of these drugs were detected over Region 2. Subsequent time-course changes in the concentration of drugs in hair demonstrated that the drugs once incorporated into white hair via Region 2 decreased gradually over the period from 24 h to 35 days after intake, but those of black hairs remained almost unchanged. These findings revealed here suggest that hair pigments have two important roles in the distribution of drugs: (1) incorporation of drugs into hair via Region 1, and (2) retention of already incorporated drugs in the hair tissue. These findings would be useful for discussing individual drug-use history based on hair analysis in the forensic fields.

[Research on Utilization of LCD Monitors Substitute for Light Box about Hard-copy Diagnosis in an Emergency by Using Receiver Operating Characteristic Analysis].

The creation of the business continuity plan (BCP) for disaster key hospitals were mandated by the Ministry of Health, Labor and Welfare on March 31, 2017. The creation of BCP must take countermeasures assuming damage at all levels. In Japan, a light box is no longer being used by a shift to soft-copy diagnosis. However, supposing the hospital network failure occurred, we assumed the film diagnosis was necessary for radiological examination images. The purpose of this study is to investigate whether the film diagnosis using a medical monitor with high luminance (410, 800 cd/m2) instead of the light box is inferior or not to a monitor diagnosis (410 cd/m2) in detecting pulmonary nodules. Ten radiological technologists participated in the observer tests for detection of nodules, respectively. In each observer test, radiological technologists marked their confidence levels for the diagnosis of pulmonary nodules. The detection performance of radiological technologists was evaluated by receiver operating characteristic (ROC) analysis. The average area under the ROC curve (AUC) value in detecting pulmonary nodules with monitor (410 cd/m2) and film (410 cd/m2), film (800 cd/m2) were 0.770 and 0.754, 0.806 respectively. There was no statistically significant difference between monitor (410 cd/m2) and film (410, 800 cd/m2) for detection of pulmonary nodules (P=0.32, 0.09). Therefore, we believe that the film diagnosis can be used for the medical monitor instead of the light box when film operation in case of a disaster inevitable.

[Hair Testing for Drugs in the Field of Forensics].

Hair testing for drugs has been used extensively in the field of forensics since the 1990s as a means of obtaining firm evidence of drug ingestion. In addition to its longer detection windows, hair is the only specimen that can provide chronological information on individual drug use. Illicit drugs and hypnotics account for the majority of substances involved in crimes; they are usually analyzed to prove an addictive use or an exposure to drugs in drug-facilitated crimes. The mechanism of drug incorporation into hair has been intensively investigated to properly interpret the results of hair analysis. However, the exact mechanism remains under much discussion, despite the growing application of hair tests. Recently, the authors have applied matrix-assisted laser desorption/ionization-mass spectrometry (MALDI-MS) imaging and sectional hair analysis of 1-mm segments using liquid chromatography-tandem mass spectrometry (LC-MS/MS) for single-strand hair, to investigate the incorporation pathways of drugs into hair. Time-course changes in drug distribution along single-strand hair suggest that the incorporation of drugs occurs in two regions of the hair root, the hair bulb and the upper part of hair root, and suggest that incorporation from the hair bulb continues for about 2 weeks. Distribution profiles of different drugs in hair additionally revealed that the main incorporation pathway varies (i.e., via the hair bulb or the upper part of hair root) depending on the properties of the drug/metabolite. These findings should be taken into account upon discussing individual drug-use history based on the results of hair analysis.

Metabolism of α-PHP and α-PHPP in humans and the effects of alkyl chain lengths on the metabolism of α-pyrrolidinophenone-type designer drugs.

PURPOSE: This study aims to investigate the urinary metabolites of two common α-pyrrolidinophenones (PPs), α-pyrrolidinohexiophenone (α-PHP) and α-pyrrolidinoheptanophenone (α-PHPP). This report also aims to discuss the effects of alkyl chain lengths on the metabolism of PPs. METHODS: Urinary metabolites of α-PHP and α-PHPP have been investigated by analyzing urine samples from their users (n = 13 each) by liquid chromatography-high-resolution tandem mass spectrometry using reference standards of the metabolites synthesized in our laboratory. RESULTS AND CONCLUSIONS: For both drugs, metabolites via reduction of the keto moiety (1-OH metabolites) and via oxidation of the pyrrolidine ring (2″-oxo metabolites) were identified, and those via oxidation of the terminal (ω) or penultimate (ω-1) positions of the alkyl chain were tentatively identified. Quantitative analysis indicated oxidation of the pyrrolidine ring to be the major metabolic pathway for α-PHP (side chain R: hexyl), but ω or ω-1 oxidation was the major metabolic pathway for α-PHPP (R: heptyl). Comparison of their metabolic profiles with those of analogs with a longer or shorter side chain (studied previously for R: butyl, pentyl, and octyl) revealed that the alkyl chain length strongly influences the metabolic pathway. In addition, to the best of our knowledge, this is the first report describing the quantification of metabolites of α-PHP and α-PHPP in authentic urine specimens collected from the users using their reference standards synthesized.

Detection of butane gas inhalation at 16days after hypoxic encephalopathy: A case report.

In Japan, there are increasing reports of death by poisoning following butane abuse. To determine the specific cause of death in such cases, it is important to confirm the presence of fuel gas components in the body, although careful analysis is required because of their volatile properties. In most reported cases, the subject died suddenly during or immediately after butane aspiration. Thus, the butane concentration in the samples from the deceased should be relatively high. Herein, we present a case of an 18-year-old man found with cardiopulmonary arrest, who then exhibited hypoxic encephalopathy for 16days in a hospital. At autopsy, we detected hypoxic encephalopathy, pneumonia, and ischemia-reperfusion injury of the myocardium, while the cause of cardiac arrest remained unclear. Toxicological analysis was then performed for fuel gas components in several specimens collected at autopsy. Results showed that n-butane and isobutane were detected in the adipose tissue at 16days after inhalation, indicating a role of butane gas inhalation as the cause of death. These data suggest that adipose tissue may be the most appropriate analysis sample to be collected at postmortem in cases where involvement of volatile and fat-soluble gas inhalation is suspected.

Incorporation of Zolpidem into Hair and Its Distribution after a Single Administration.

To obtain fundamental information on the drug incorporation into hair, time-course changes in drug distribution along single-strand hair were observed after a single oral administration of zolpidem (ZP), one of the most frequently used hypnotic agents. Quantitative sectional hair analyses of 1-mm segments were performed for each single-strand hair using a validated LC-MS/MS procedure. ZP was detected in all specimens plucked at 10 and 24 hours after a single dose, and the distribution ranged over the whole hair root (4-5 mm in length). A significantly high concentration of ZP was detected in the hair bulb region, whereas much lower concentrations were widely observed in the upper part of the hair root of those samples; this suggested that the incorporation of ZP occurred in two regions, mainly in the hair bulb and to a lesser extent in the upper dermis zone. The ZP-positive area formed lengths of up to 10-12 mm after a single administration, indicating that its incorporation from the hair bulb would continue for about 2 weeks. Time-course changes in the ZP concentration in the hair root additionally revealed that only a small portion of ZP that initially concentrated in the bulb was successively incorporated into the hair matrix and moved toward the keratinized region as hair grew. These findings should be taken into account upon discussing individual drug-use history based on hair analysis. The matrix-assisted laser desorption/ionization mass spectrometry imaging of ZP in the same kinds of hair specimens was also successfully achieved.