Incidence and factor analysis of laryngohyoid fractures in hanging individuals-computed tomography study.

OBJECTIVES: Although laryngohyoid fracture indicates the applied neck pressure and is an important finding in hanging individuals, the reported rate varies widely and its true incidence remains controversial. We used computed tomography (CT) studies to investigate the incidence of laryngohyoid fracture in hanging individuals and identify factors contributing to such fractures. METHODS: Considered for inclusion in this study were 107 attempted or successful hanging individuals subjected to CT studies between 2005 and 2019. After excluding 19 whose images were inadequate for evaluation, 88 subjects were included. Body suspension was complete in 20, partial in 49, and unknown in 19; 54 (61.4%) individuals died. Two radiologists performed image analysis and recorded the presence and site of laryngohyoid fractures. Multiple logistic regression analysis was used for factor analysis of laryngohyoid fractures; it included the gender, the age (< or ≧ 40 years), the type of suspension (complete or incomplete), and the outcome (death or survival). RESULTS: Of the 88 subjects, 35 (39.8%) presented with laryngohyoid fractures on CT images; the superior horn of the thyroid cartilage was fractured in 32 (91.4%) of the 35. Age was the only factor significantly related to laryngohyoid fracture (odds ratio = 2.85, 95% confidence interval = 1.08-7.52). CONCLUSIONS: In hanging individuals, the incidence of laryngohyoid fracture on CT images was 39.8%. The superior horn of the thyroid cartilage was the most frequent fracture site. KEY POINTS: • The incidence of laryngohyoid fracture on CT images of hanging individuals was almost 40%; the superior horn of the thyroid cartilage was the most frequent fracture site. • In older hanging individuals, attention must be paid to laryngohyoid fractures on CT images.

The Sarin-like Organophosphorus Agent bis (isopropyl methyl)phosphonate Induces Apoptotic Cell Death and COX-2 Expression in SK-N-SH Cells.

Organophosphorus compounds, such as sarin, are highly toxic nerve agents that inhibit acetylcholinesterase (AChE), but not cholinesterase, via multiple mechanisms. Recent studies have shown that organophosphorus compounds increase cyclooxygenase-2 (COX-2) expression and induce neurotoxicity. In this study, we examined the toxicity of the sarin-like organophosphorus agent bis(isopropyl methyl)phosphonate (BIMP) and the effects of BIMP on COX-2 expression in SK-N-SH human neuroblastoma cells. Exposure to BIMP changed cell morphology and induced caspase-dependent apoptotic cell death accompanied by cleavage of caspase 3, caspase 9, and poly (ADP-ribose) polymerase (PARP). It also increased COX-2 expression, while pretreatment with a COX inhibitor, ibuprofen, decreased BIMP-dependent cell death and COX-2 expression in SK-N-SH cells. Thus, our findings suggest that BIMP induces apoptotic cell death and upregulates COX-2 expression.

Experimental studies of remarkable monoamine releases and neural resistance to the transient ischemia and reperfusion.

INTRODUCTION: The literature described that neural damage caused by ischemia definitely occurs in brain areas. However, few studies have shown real-time changes of extracellular monoamine levels at the time of transient ischemia. METHODS: We examined changes in the responses of dopamine (DA) and serotonin (5-HT) release in the nucleus accumbens (ACC) of rats treated with four-vessel occlusion (4VO) in experiment 1. In the second experiment, we investigated the selective neural vulnerabilities among the ACC, lateral hypothalamus (LH), and frontal cortex (FC) of rats treated with 4VO and four days of reperfusion. RESULTS: The extracellular levels of DA and 5-HT were remarkably increased 200- and 20-fold upon the 10-min clipping of both common carotid arteries in transient cerebral ischemia, respectively. Each increased monoamine release returned to the baseline levels immediately. The release of DA in the ACC and FC was significantly decreased in the rats treated with the coagulation of bilateral vertebral arteries (2VO), compared with that of sham-operated rats. K(+)-induced DA release in the ACC and FC of 4VO-treated rats was increased without alteration of DA content. DISCUSSION: Surviving dopaminergic neurons in the ACC and FC showed neural hyperfunction associated with the monoamine release, serotonergic neurons in particular these areas exhibiting functional resistance to the transient ischemic change. CONCLUSION: It is suggested that the remarkable extracellular release of DA and 5-HT was not the cause of the ischemic delayed neural degeneration in each brain area, and that the functions of neurotransmitter release involved remarkable resistance to the transient ischemia.

[Cross-reactivity of Instant-View M-1 for detection of benzodiazepine-related drugs and their metabolites in urine].

Immunoassays are useful methods for the determination of regulated drugs in clinical and forensic laboratories. Although the Instant-View M-1 (IV M-1) immunoassay kit is frequently used to screen drugs in laboratories in Japan, basic information about the IV M-1 such as its specificity and reactivity is not available. In this study, we determined the specificity and cross-reactivity of IV M-1 for the detection of benzodiazepine-related drugs and their metabolites in urine. The IV M-1 could detect triazolobenzodiazepines such as triazolam in urine at concentrations > or = 300 ng/mL. However, thienodiazepines such as etizolam could not be detected because of lack of cross reactivity. A correlation was observed between the structure of the metabolites and the reactivity of the kit; 4-hydroxy metabolites of alprazolam and triazolam were detectable, whereas a-hydroxy metabolites were not. Furthermore, 7-amino metabolites such as nitrazepam could not be detected at any concentration, including high concentrations. The specificity and reactivity of various kits used for detection of drugs in urine are different. Therefore, it is necessary to consider the basic features of the kit used while assessing the results obtained.

Metal component of dental restorations and fixed prostheses in the oral cavity of 43 cases of adults aged 55 years or older in forensic autopsy.

Characterization of the metal component of dental restorations and fixed prostheses is useful for the treatment of dental metal allergies and personal identification. This study aimed to describe the composition of metal elements in dental restorations and fixed prostheses in the oral cavity of 43 cadavers of Japanese adults aged 55 years or older in forensic autopsies conducted at a university. In this study, Ag-Pd-Au alloys were most frequently detected, and the percentage of Ni alloys was smaller than that reported in patients with dental metal allergies. Furthermore, alloys containing other elements, such as Fe or Hg, were also detected in some cases.

Development of a deep-learning algorithm for age estimation on CT images of the vertebral column.

PURPOSE: The accurate age estimation of cadavers is essential for their identification. However, conventional methods fail to yield adequate age estimation especially in elderly cadavers. We developed a deep learning algorithm for age estimation on CT images of the vertebral column and checked its accuracy. METHOD: For the development of our deep learning algorithm, we included 1,120 CT data of the vertebral column of 140 patients for each of 8 age decades. The deep learning model of regression analysis based on Visual Geometry Group-16 (VGG16) was improved in its estimation accuracy by bagging. To verify its accuracy, we applied our deep learning algorithm to estimate the age of 219 cadavers who had undergone postmortem CT (PMCT). The mean difference and the mean absolute error (MAE), the standard error of the estimate (SEE) between the known- and the estimated age, were calculated. Correlation analysis using the intraclass correlation coefficient (ICC) and Bland-Altman analysis were performed to assess differences between the known- and the estimated age. RESULTS: For the 219 cadavers, the mean difference between the known- and the estimated age was 0.30 years; it was 4.36 years for the MAE, and 5.48 years for the SEE. The ICC (2,1) was 0.96 (95 % confidence interval: 0.95-0.97, p < 0.001). Bland-Altman analysis showed that there were no proportional or fixed errors (p = 0.08 and 0.41). CONCLUSIONS: Our deep learning algorithm for estimating the age of 219 cadavers on CT images of the vertebral column was more accurate than conventional methods and highly useful.

Acute effects of a sarin-like organophosphorus agent, bis(isopropyl methyl)phosphonate, on cardiovascular parameters in anaesthetized, artificially ventilated rats.

The organophosphorus compound sarin irreversibly inhibits acetylcholinesterase. We examined the acute cardiovascular effects of a sarin-like organophosphorus agent, bis(isopropyl methyl)phosphonate (BIMP), in anaesthetized, artificially ventilated rats. Intravenous administration of BIMP (0.8mg/kg; the LD50 value) induced a long-lasting increase in blood pressure and tended to increase heart rate. In rats pretreated with the non-selective muscarinic-receptor antagonist atropine, BIMP significantly increased both heart rate and blood pressure. In atropine-treated rats, hexamethonium (antagonist of ganglionic nicotinic receptors) greatly attenuated the BIMP-induced increase in blood pressure without changing the BIMP-induced increase in heart rate. In rats treated with atropine plus hexamethonium, intravenous phentolamine (non-selective α-adrenergic receptor antagonist) plus propranolol (non-selective ß-adrenergic receptor antagonist) completely blocked the BIMP-induced increases in blood pressure and heart rate. In atropine-treated rats, the reversible acetylcholinesterase inhibitor neostigmine (1mg/kg) induced a transient increase in blood pressure, but had no effect on heart rate. These results suggest that in anaesthetized rats, BIMP induces powerful stimulation of sympathetic as well as parasympathetic nerves and thereby modulates heart rate and blood pressure. They may also indicate that an action independent of acetylcholinesterase inhibition contributes to the acute cardiovascular responses induced by BIMP.

Dental radiographic information of term newborn babies within the first month: Analyzing five radiographic cases along with physical attributes in Japan.

BACKGROUND: Although dental radiography is a valuable tool for age estimation in forensic anthropology and odontology, very limited radiological data are available regarding tooth development in healthy newborn babies during the first month of life. AIM: This study aimed to describe the radiological findings of tooth development in babies aged 0 days to 1 month. DESIGN: We analyzed the postmortem findings of five newborn babies with no known natural cause of death who had undergone autopsy, computed tomography (CT), and dental radiography. We estimated the gestational age for the babies aged 0 days and analyzed the condition of mandibular symphysis, existence of tooth germs, and presence or absence of calcification of the first permanent molars of all the babies. RESULTS: The calcified form of 20 deciduous teeth, tooth germs of the permanent upper and lower first molars, and non-calcified mandibular symphysis were observed in each case. However, calcification of the first permanent molar was observed in only two 1-month-old babies. CONCLUSION: The dental radiographic findings and anthropometric measurements of non-skeletonized, non-mummified term babies confirmed calcification of all the deciduous teeth and the first permanent molar at the age of 0 days and 1 month, respectively.

Age estimation using post-mortem computed tomography and fetal dental radiographic findings in an early to mid-pregnancy fetus: A case report.

Parameters for body size growth are essential to evaluate the relationship between fetal growth and accurate age estimation in forensics. Size values measured postmortem are also affected by the postmortem environment. On the contrary, when using hard tissue maturation criteria, age estimation remains unaffected by the degree of fetal preservation. In Japan, a fetus dying 12 weeks after pregnancy must be reported as a stillbirth. A Japanese stillborn infant buried without reporting to the authorities underwent a forensic autopsy. The gestational age was 4-5 months, based on the mother's description. The body was not fixed, and it was macerated and flattened along the sagittal plane; therefore it was difficult to correctly measure indicators involving soft tissue. The bone size and tooth development were evaluated using postmortem computed tomography (CT) images and intraoral radiography to estimate the age. Considering all the information, including age estimation based on bone sizes referenced in a Japanese study, calcified upper central incisors, we estimated fetal gestational age for our sample as 14-17 gestational weeks finally. However, there were discrepancies between age estimations based on bone size (20-25 gestational weeks, bone radiographic imaging standards; or 4-6 gestational months, an average of the extremity-bones by a Japanese study) and tooth development (14-17 gestational weeks). Deep discussions based on multiple indices with professionals should be applied to forensic age estimation since existing methods may be based on data for different races, use other measurement tools, or apply different sample conditions even if the targets are the same.

Comparison of therapeutic effects of mesenchymal stem cells derived from superficial and deep subcutaneous adipose tissues.

BACKGROUND: Fibrosis is a common histological feature in the process from chronic organ injury to organ failure. Chronic tissue injury causes inflammatory cell infiltration into the injured tissue. The persistence of this inflammatory cell infiltration leads to fibrosis and organ failure. Adipose-derived mesenchymal stem cells (ASCs) have received much attention as a regenerative therapeutic tool to prevent progression from organ injury to failure. Subcutaneous abdominal adipose tissue is divided into superficial and deep layers by a superficial fascia. Adipose tissue easily collected by liposuction is usually obtained from a deep layer, so ASCs derived from a deep layer are generally used for regenerative medicine. However, no research has been conducted to investigate differences in the therapeutic effects of ASCs from the superficial and deep layers (Sup-ASCs and Deep-ASCs, respectively). Therefore, we compared the therapeutic potencies of Sup-ASCs and Deep-ASCs. METHODS: ASCs were isolated from superficial and deep subcutaneous abdominal adipose tissues collected from patients who underwent breast reconstruction. We first compared cell characteristics, such as morphology, cell proliferation, cell surface markers, adipogenic and osteogenic differentiation, cell senescence markers, and expression of coagulation and anticoagulant factors between Sup-ASCs and Deep-ASCs. Furthermore, we compared their ability to promote polarization of M2 macrophages and to inhibit transforming growth factor (TGF)-ß/Smad signaling using THP-1 cells and TGF-ß1 stimulated HK-2 cells incubated with conditioned media from Sup-ASCs or Deep-ASCs. In in vivo experiments, after renal ischemia-reperfusion injury (IRI) procedure, Sup-ASCs or Deep-ASCs were injected through the abdominal aorta. At 21 days post-injection, the rats were sacrificed and their left kidneys were collected to evaluate fibrosis. Finally, we performed RNA-sequencing analysis of Sup-ASCs and Deep-ASCs. RESULTS: Sup-ASCs had greater proliferation and adipogenic differentiation compared with Deep-ASCs, whereas both ASC types had similar morphology, cell surface markers, senescence markers, and expression of coagulation and anticoagulant factors. Conditioned media from Sup-ASCs and Deep-ASCs equally promoted polarization of M2 macrophages and suppressed TGF-ß/Smad signaling. Moreover, administration of Sup-ASCs and Deep-ASCs equally ameliorated renal fibrosis induced by IRI in rats. RNA-sequencing analysis revealed no significant difference in the expression of genes involved in anti-inflammatory and anti-fibrotic effects between Sup-ASCs and Deep-ASCs. CONCLUSIONS: These results indicate that both Sup-ASCs and Deep-ASCs can be used effectively and safely as an intravascular ASC therapy for organ injury.

Sequential extraction of inorganic arsenic compounds and methyl arsenate in human urine using mixed-mode monolithic silica spin column coupled with gas chromatography-mass spectrometry.

A sequential analytical method was developed for the detection of arsenite, arsenate, and methylarsenate in human urine by gas chromatography-mass spectrometry (GC-MS). The combination of a derivatization of trivalent arsenic compounds by 2,3-dithio-1-propanol (British antilewisite; BAL) and a reduction of pentavalent arsenic compounds (arsenate and methylarsenate) were accomplished to carry out the analysis of arsenic compounds in urine. The arsenic derivatives obtained using BAL were extracted in a stepwise manner using a monolithic spin column and analyzed by GC-MS. A linear curve was observed for concentrations of arsenic compounds of 2.0 to 200 ng/mL, where the correlation coefficients of calibration curves were greater than 0.996 (for a signal-to-noise (S/N) ratio >10). The detection limits were 1 ng/mL (S/N > 3). Recoveries of the targets in urine were in the range 91.9-106.5%, and RSDs of the intra- and interday assay for urine samples containing 5, 50, and 150 ng/mL of arsenic compounds varied between 2.95 and 13.4%. The results from real samples obtained from a patient suspected of having ingested As containing medications using this proposed method were in good agreement with those obtained using high-performance liquid chromatography with inductively coupled plasma mass spectrometry.

Acute intoxication caused by overdose of flunitrazepam and triazolam: high concentration of metabolites detected at autopsy examination.

A 52-year-old woman was found dead on the floor of the living room on the first floor of a house, which belonged to the man with whom she shared the house. On visiting the site, her clothes were found to be undisturbed. Packages of flunitrazepam (Silece, 2 mg/tablet) and triazolam (Halcion, 0.25 mg/tablet) were found strewn around the victim. Toxicological analysis was performed, and the concentrations of flunitrazepam, triazolam, and their metabolites in the victim's blood and urine were measured by high-performance liquid chromatography coupled with photodiode array and mass spectrometry. A high blood concentration of 7-aminoflunitrazepam was detected (1,270 ng/g), and further metabolites such as 7-acetamidoflunitrazepam, 7-acetamidodesmethylflunitrazepam, and 7-aminodesmethylflunitrazepam were detected in the blood and urine samples. In addition, 4-hydroxytriazolam and α-hydroxytriazolam were detected in her urine at a concentration of 950 and 12,100 ng/mL, respectively.On the basis of the autopsy findings and toxicology results of high concentrations of both flunitrazepam and triazolam derivatives, the cause of death was determined to be acute intoxication from flunitrazepam and triazolam.

Gender differences in D-aspartic acid content in skull bone.

In forensic medicine, the personal identification of cadavers is one of the most important tasks. One method of estimating age at death relies on the high correlation between racemization rates in teeth and actual age, and this method has been applied successfully in forensic odontology for several years. In this study, we attempt to facilitate the analysis of racemized amino acids and examine the determination of age at death on the basis of the extent of aspartic acid (Asp) racemization in skull bones. The specimens were obtained from 61 human skull bones (19 females and 42 males) that underwent judicial autopsy from October 2010 to May 2012. The amount of D-Asp and L-Asp, total protein, osteocalcin, and collagen I in the skull bones was measured. Logistic regression analysis was performed for age, sex, and each measured protein. The amount of D-Asp in the female skull bones was significantly different from that in the male skull bones (p = 0.021), whereas the amount of L-Asp was similar. Thus, our study indicates that the amount of D-Asp in skull bones is different between the sexes.

A method for determining valproic acid in human whole blood and urine via gas chromatography-mass spectrometry and small-scale inter-laboratory trial.

A simple and cost-effective method for analyzing valproic acid (VPA) in biological samples was developed. VPA was extracted in methyl tertiary-butyl ether (MTBE) and derivatized using trimethylsilyldiazomethane. The MTBE extract was analyzed by gas chromatography-mass spectrometry (GC-MS). The extraction recovery in human whole blood and urine was over 90 %, with good linearity in the range of 1.0 to 250 µg/mL of VPA. The RSD for 2.0, 20, and 200 µg/mL VPA in whole blood ranged from 0.9 to 4.7 % for intra-day and 1.5 to 5.9 % for inter-day. The RSD for 2.0, 20, and 200 µg/mL VPA in urine ranged from 1.9 to 2.6 % for intra-day and 1.2 to 2.9 % for inter-day. As a preliminary cross-validation study, a cross-check was conducted using blinded concentration samples. The results demonstrated that the assay data of the two laboratories were comparable.

Global illumination rendering versus volume rendering for the forensic evaluation of stab wounds using computed tomography.

We compared three-dimensional (3D) CT images of stabbing victims subjected to volume-rendering (VR) or global illumination-rendering (GIR), a new technique now available for the reconstruction of 3D CT images. It simulates the complete interactions of photons with the scanned object, thereby providing photorealistic images. The diagnostic value of the images was also compared with that of macroscopic photographs. We used postmortem 3D CT images of 14 stabbing victims who had undergone autopsy and CT studies. The 3D CT images were subjected to GIR or VR and the 3D effect and the smoothness of the skin surface were graded on a 5-point scale. We also compared the 3D CT images of 37 stab wounds with macroscopic photographs. The maximum diameter of the wounds was measured on VR and GIR images and compared with the diameter recorded at autopsy. The overall image-quality scores and the ability to assess the stab wounds were significantly better on GIR than VR images (median scores: VR = 3 vs GIR = 4, p < 0.01). The mean difference between the wound diameter measured on VR and GIR images and at autopsy were both 0.2 cm, respectively. For the assessment of stab wounds, 3D CT images subjected to GIR were superior to VR images. The diagnostic value of 3D CT GIR image was comparable to that of macroscopic photographs.

Four cases of cytokine storm after COVID-19 vaccination: Case report.

The global coronavirus disease 2019 (COVID-19) pandemic has led to the rapid development of vaccines against this disease. Despite the success of the international vaccination program, adverse events following vaccination, and the mechanisms behind them, remain poorly understood. Here we present four cases of death following receipt of a second dose of COVID-19 vaccine, with no obvious cause identified at autopsy. Using RNA sequencing, we identified genes that were differentially expressed between our post-vaccination cases and a control group that died of blood loss and strangulation. Three hundred and ninety genes were found to be upregulated and 115 genes were downregulated in post-vaccination cases compared with controls. Importantly, genes involved in neutrophil degranulation and cytokine signaling were upregulated. Our results suggest that immune dysregulation occurred following vaccination. Careful observation and care may be necessary if an abnormally high fever exceeding 40°C occurs after vaccination, even with antipyretic drugs.

Confirmation that SNPs in the high mobility group-A2 gene (HMGA2) are associated with adult height in the Japanese population; wide-ranging population survey of height-related SNPs in HMGA2.

Adult height is a highly heritable trait in that multiple genes are involved. Recent genome-wide association studies have identified a novel single-nucleotide polymorphism (SNP) rs1042725 in the high mobility group-A2 gene (HMGA2) and shown it to be associated with human height in Caucasian populations. We performed a replication study to examine the associations between SNPs in HMGA2 and adult height in the Japanese population based on autopsy cases. Although we could not confirm a significant association between rs1042725 in HMGA2 and adult height, another SNP, rs7968902, in the gene achieved significance for its association in the same populations, and the effect was the same as that documented previously. These findings permit us to conclude that the SNPs in HMGA2 are common variants influencing human height across different populations. Moreover, a worldwide population study of these SNPs using 14 different populations including Asians, Africans and Caucasians demonstrated that both haplotypes and genotypes for three height-related SNPs (rs1042725, rs7968682 and rs7968902) in HMGA2 were distributed in an ethnicity-dependent manner. This information will be useful for clarifying the genetic basis of human height.

Simultaneous extraction of acidic and basic drugs from urine using mixed-mode monolithic silica spin column bonded with octadecyl and cation-exchange group.

A method coupling spin column extraction with gas chromatography-mass spectrometry was developed for the simultaneous extraction of acidic and basic drugs from urine. Benzodiazepines, local anaesthetics, antidepressants, and barbiturates were used as model drugs. Sample loading, washing, and elution of the target drugs were accomplished by centrifugation of the column. In this study, mixed-mode monolithic silica bonded with a C18 reversed-phase and a strong cation exchange phase was packed in a spin column. The pH of a urine sample (0.2 mL) was adjusted to 3 and the analytes adsorbed onto the column were eluted with 0.1 mL of MeOH containing 2% NH3; all the tested drugs were simultaneously extracted from urine. The recovery of the tested drugs was 65-123%. Up to a concentration of 2500 ng/mL of the target drugs in urine, a linear curve was observed (r(2)>0.996). The intra- and interday RSDs at three different concentrations in urine were 2.1-14.7%. For RSDs lower than 15%, the limits of detection were 1-25 ng/mL. The proposed method was successfully applied for clinical and forensic cases and the results thus obtained were in good agreement with those obtained by conventional methods.

[Comparison of four immunoassay screening devices for detection of benzodiazepine and its metabolites in urine: mainly detection of etizolam, thienodiazepine and its metabolites].

The immunoassay screening of benzodiazepines in urine is one of the most important methods of drug analysis in clinical and forensic laboratories. We experienced an unusual case of poisoning wherein the result of Triage DOA immunoassay screening was negative, although Depas (etizolam) was detected in the blood of the victim who had been suspected to prescribe Depas by gas chromatography-mass spectrometry. Depas has been widely used for the treatment of anxiety in Japan. Three immunoassay screening devices (AccuSign BZO, Monitect-3, and Fastect II) were evaluated for their specificity for etizolam, its 2 major metabolites M-III and M-VI, and other metabolites of benzodiazepines in urine. With AccuSign BZO, etizolam, M-III, and M-VI could be detected at concentrations of 1,000 ng/mL in urine; however, they could not be detected even at concentrations of 25,000 ng/mL with the other kits. In the case of etizolam poisoning, the result of AccuSign BZO was positive; however, Triage DOA, which is mainly used for the detection of drugs in urine at intensive care units (ICUs) or forensic laboratories, showed negative result for benzodiazepines. The concentrations of etizolam and its metabolites in urine were measured by the established high-performance liquid chromatographic method. The concentrations of M-III and M-V were 700 and 1,600 ng/mL, respectively. AccuSign BZO demonstrated higher specificity-than the other screening kits for the detection of etizolam and its metabolites in urine. Therefore, the types of drugs detected would be increased by combining Triage DOA with AccuSign BZO in ICUs or forensic laboratories.

BIMP affects tubulin structure and causes abnormalities in cell division.

Although organophosphorus agents are used worldwide as pesticides, there have been many reports of pesticide poisoning. Nerve agents are organophosphorus agents that interfere with neurotransmission and have been used as chemical weapons in wars. These agents mainly irreversibly inhibit the action of acetylcholinesterase, an enzyme that breaks down acetylcholine, a neurotransmitter, and are believed to cause acute symptoms of poisoning. However, in recent years, the presence of subacute, delayed toxicity independent of acetylcholinesterase inhibition has been reported for some organophosphorus agents. We analyzed the subacute and delayed toxicity of bis(isopropylmethyl)phosphonate (BIMP), which has the same phosphonate group as sarin. BIMP rounded out the morphology of the cells and reduced the proportion of cells in the G1 phase of the cell cycle over time. No DNA damage was observed, suggesting that BIMP may affect cell division.