Layer-specific proteomic profiling of human normal heart.

BACKGROUND: The organized functioning of the anisotropic myocardial layers-including the inner longitudinal, middle circular, and outer longitudinal layers-is essential for stable systemic circulation. However, the proteomic profile of each myocardial layer has not been studied yet. Here, we aimed to elucidate the layer-specific proteomic profile of human cardiac tissue using microscopic sampling. METHODS: Normal hearts were obtained from five autopsy cases, and cardiomyocytes were microdissected separately from the three myocardial layers of the left ventricle. Histological analysis and shotgun proteomic profiling were performed, followed by immunohistochemical analysis. RESULTS: Histologically, no significant changes were observed among the three layers regarding cardiomyocyte diameter and myocardial fibrosis. Totally 1220 proteins-comprising 9404 peptides-were identified from 15 samples, of which the expression levels of 92 proteins were significantly altered among the layers. Gene ontology enrichment analysis revealed that the proteins specifically elevated in the inner and outer layers mostly belonged to the actin filament-binding protein group. In particular, MYH1 was highly expressed in cardiomyocytes in the outer layer, and CTNNA3 was highly expressed at the intercalated disc in the inner layer. CONCLUSIONS: This is the first report on layer-specific proteomic profiling of human normal hearts. Anisotropic profiles of actin filament-binding proteins in myocardial layers may contribute to the anisotropic contractile and conductive abilities of the heart. Knowledge of the layer-specific proteome profiles of a human heart in the normal state can aid in further research on cardiac pathology, such as the prognosis and treatment of focal myocardial infarction.

Construction of 13-locus X-STR multiplex PCR system that reinforces Argus X-12 kit discrimination capacity: Application to the Malay population.

Closely linked groups of markers on the X chromosome are very useful for testing complex kinship relationships involving X-STR transmission. The Argus X-12 kit, a unique commercially available kit, can obtain haplotypes of 4 linkage groups (LGs) consisting of 3 markers. Although many population data have been reported for forensic purposes, differences in discrimination ability exist between LG1 and LG2, 3, and 4 in East Asian populations, and the data of this kit would become more useful if the discrimination ability of the latter groups were increased. Therefore, for matches found using this kit for some linkage group data, then to increase the identification ability, we additionally introduced 13 X-STR loci and established a method allowing comparison using data from 25 loci. The 13X-STRs add two locus data to each of LG2, 3, and 4, and also add two closely linked group (CLG) data between LG2 and 3 and LG3 and 4 in one multiplex PCR. Assessment of this method for a Malay population for which data by Argus X-12 had already been reported showed that the frequencies of distinct haplotypes in LG2, 3, and 4 were increased by 33.0-42.6 %, and frequencies of unique haplotypes increased by 45.4-59.2 %. The respective haplotype diversity values of the additional 3-locus and 4-locus CLGs were 0.9838 and 0.9939, which helps to improve discriminatory power and to predict recombination locations on the X chromosome. Although we have been testing these loci with Japanese subjects, this system would also be useful for the Malay population.

Forensic Characteristics of Body Abandonment by Housemates in Japan.

INTRODUCTION:  In Japan, many cases occur wherein housemates fail to report dead bodies found in their homes. However, only individual cases are reported through press and court records, and analysis including unreported cases has not been conducted. In this study, we evaluated cases handled by our Forensic Science Department in which housemates did not immediately report a dead body found in their home. We analyzed the overall picture and forensic characteristics of such cases, stratifying whether the abandoners were estimated hikikomori. METHODS:  Of the 1,179 legal autopsy cases handled by the Department of Forensic Medicine of Tokai University from January 1, 2017, to July 1, 2023, we evaluated 45 cases in which housemates did not immediately report dead bodies. The characteristics analyzed were body age, cause of death, autopsy findings, duration from the body's discovery by the abandoner to the police report, the reason for the lack of report in the first body discovery by the abandoner, and the reason for the report. In this study, the criteria for estimating whether a hikikomori abandoned the body were (1) the police provided the information that the person was a hikikomori or (2) the person met the following four criteria: 20-64 years old, unemployed, not in school, and living with parents. RESULTS:  Positive significant differences were found in the body's decomposition and the time from the body's discovery to the report to the police when the abandoner was suspected to be a hikikomori for more than one, four, or eight days. No significant differences were found in the cause of death. Regarding the reported characteristics, when the abandoner was an estimated hikikomori, positive and significant differences were found for recognizing the body and did not report immediately due to shock. Conversely, negative and significant differences were found for the person who reported as the abandoner. CONCLUSION:  This is the first study that reports on body abandonment by housemates and elaborates on its complications to forensic doctors. The incidence rate of abandonment is higher than expected. This study suggests that hikikomori are more likely to hide the bodies for longer, which hinders the death cause investigation.

Unexpected sudden death on arrival in a healthy middle-aged man associated with COVID-19-related diffuse cardiac injury: A case report.

Coronavirus disease 2019 (COVID-19) is an emerging respiratory infectious disease caused by severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2). COVID-19 has been reported to lead to acute cardiac injury, but previous research indicated that the mechanism is different from that of other viruses and remains poorly understood. Herein, we describe a case of COVID-19-associated sudden death, in a healthy 47-year-old man after developing diffuse cardiac necrosis. Two days before death, the patient developed general malaise without respiratory symptoms. The patient's fatigue worsened with time, and he ultimately developed cardiac arrest in an ambulance; however, resuscitation was unsuccessful. Antigen testing performed at the hospital revealed that the patient was positive for SARS-CoV-2 virus. At autopsy, contraction band necrosis was observed insularly in all areas of the myocardium. CD42b immunohistochemical staining indicated platelet aggregation in the microvessels around the cardiac necrosis area, suggesting COVID-19 can be fatal for healthy people by microcirculatory disturbance due to diffuse cardiac injury arising from platelet activiation. This unique mechanism can be a novel therapeutic target of COVID-19-related cardiac injury.

A case of a motor vehicle collision suspected as associated with development of angiosarcoma.

Trauma has been suspected as a factor leading to development of angiosarcoma, a malignant soft-tissue tumor. We conducted a forensic autopsy to investigate a putative relation between a motor vehicle collision and the driver's later death from angiosarcoma. A vehicle operated by a man in his 60 s collided with an oncoming vehicle at a curve. The victim noticed no injury at the scene. However, 45 days later, he was transferred to an emergency room with dyspnea and bloody sputum. After diagnosis of angiosarcoma, he died of respiratory failure 132 days later. The bereaved family speculated about a relation between the collision and angiosarcoma onset. At autopsy, tumor cells of the scalp had metastasized to the lung, pleura, liver, and spleen. Histopathological examinations revealed characteristic features of angiosarcoma with positive immune-staining for CD31, CD34, and factor VIII. When a person dies some time after a collision, it is designated as a delayed death. In such cases, the relevance of trauma to the person's death is often an issue of concern. Because the interval between trauma and angiosarcoma development was short, only 45 days, the angiosarcoma might be coincidental. Therefore, we rejected the relation. Forensic experts sometimes need to investigate such inquiries.

Proteomic profiling of sudden cardiac death with acquired cardiac hypertrophy.

BACKGROUND: Cardiac hypertrophy, which develops in middle-aged and older individuals as a consequence of hypertension and obesity, is an established risk factor for sudden cardiac death (SCD). However, it is sometimes difficult to differentiate SCD with acquired cardiac hypertrophy (SCH) from compensated cardiac hypertrophy (CCH), at autopsy. We aimed to elucidate the proteomic alteration in SCH, which can be a guideline for future postmortem diagnosis. METHODS: Cardiac tissues were sampled at autopsy. SCH group consisted of ischemic heart failure, hypertensive heart failure, and aortic stenosis. CCH group included cases of non-cardiac death with cardiac hypertrophy. The control group comprised cases of non-cardiac death without cardiac hypertrophy. All patients were aged > 40 years, and hypertrophic cardiomyopathy was not included in this study. We performed histological examination and shotgun proteomic analysis, followed by quantitative polymerase chain reaction analysis. RESULTS: Significant obesity and myocardial hypertrophy, and mild myocardial fibrosis were comparable in SCH and CCH cases compared to control cases. The proteomic profile of SCH cases was distinguishable from those of CCH and control cases, and many sarcomere proteins were increased in SCH cases. Especially, the protein and mRNA levels of MYH7 and MYL3 were significantly increased in SCH cases. CONCLUSION: This is the first report of cardiac proteomic analysis in SCH and CCH cases. The stepwise upregulation of sarcomere proteins may increase the risk for SCD in acquired cardiac hypertrophy before cardiac fibrosis progresses significantly. These findings can possibly aid in the postmortem diagnosis of SCH in middle-aged and older individuals.

Physical health risks of middle-aged people with low social independence: fatal diseases in men, and little attendance to cancer screenings in both sexes.

Background: The existence of social withdrawal (Hikikomori), which meets the conditions "not attending school", "not working", and "isolated at home for more than 6 months", is gradually being discovered by the world, and their mental health and healing is being highlighted. However, there are very few Hikikomori-related surveys searching their physical health, as it is generally believed that most Hikikomori are adolescents. Middle-aged Hikikomori are also found outside Japan, and their physical health is more important, because Hikikomori have difficulty managing their health due to the socially isolated circumstances and lack of sociability. Although "isolated at home for more than 6 months" could not be used, we extracted a group with low social independence with reference to Hikikomori-related surveys. We estimate that people with low social independence have similar characteristics and problems to Hikikomori, because they share many causes for the problem of difficulty in managing their own health. People with low social independence were identified, and their physical health, such as smoking and drinking status, consultation rates of various diseases, and how often they attend cancer screenings, was analyzed. Methods: We extracted middle-aged people with low social independence and a control group from the national survey in Japan and stratified them by sex and age. Their health risks were assessed by univariate analysis. Criteria for the experimental group were set with reference to Hikikomori-related surveys. Criteria for the control group included "aged 40-69", "living with parents", "not receiving care for disabilities", and "working". Results: Low-social-independent men had higher consultation rates for diabetes, stroke or cerebral hemorrhage, myocardial infarction or angina, gastric and duodenum diseases, kidney disease, anemia, and depression, while lower consultation rates for dyslipidemia and hypertension. The tendency of non-smoking and non-drinking was found among them. They seldom attended cancer screenings. Low-social-independent women had higher consultation rates for liver and gallbladder diseases, other digestive diseases, kidney diseases, anemia, osteoporosis, and depression. The tendency of non-drinking was the same as men. More heavy smokers were found among those aged 40-49 years, with no significant differences in other age groups. They seldom attended cancer screenings, as well as men. Conclusions: In terms of current physical health, low-social-independent men have more fatal diseases. Both sexes with low social independence seldom attend cancer screenings and have an increased risk of developing progressive cancer in the future. At least in terms of non-smoking and non-drinking, they live healthier lives than the control group, and what makes low-social-independent men have various fatal diseases is still unclear.

An instance of homicide by electrocution with hand-made electrode plates.

Homicide by electrocution is rare in forensics, and the identification of the cause of death can be quite difficult when the electric device is removed from the scene. We present an instance where the police were unsure of homicide in the initial investigation. The offender used hand-made electrode plates for electrocution, which produced unique electric marks different from those produced by common electric devices such as electric wires. To the best of our knowledge, this is the first report of homicide by electrocution with electrode plates. We believe that the macroscopic and microscopic findings in this instance are quite valuable for forensic practitioners.

Gastric aspiration in sudden unexpected infant death of Prader-Willi syndrome: immunohistochemical detection of feeding components.

Prader-Willi syndrome (PWS) in infants is characterized by hypotonia and poor sucking with feeding difficulties. Two autopsy cases of sudden unexpected death during sleep after tube feeding are described herein. For one, gastric aspiration caused by the possible milk regurgitation was suspected. Immunohistochemical examination of lung sections was performed using three antibodies to human α-lactalbumin, human gross cystic disease fluid protein 15, and cow whey ß-lactoglobulin. Five cases of sudden unexpected infant death occurring earlier than at 6 months old were selected as controls. Marked immune-staining for infant formula in one PWS subject was evident within terminal bronchioles and alveoli with granular and amorphous features. However, no positive staining was apparent in the other subject, who exhibited contrasting features in milk distribution. Among control cases, one showed mild staining in the bronchiole, but the others did not. The antibody to ß-lactoglobulin reacted specifically with formula, with no nonspecific background. Gastric contents in the airway can be a difficult issue because of the consequent terminal gasping. However, because of an episode of antemortem symptoms of potential regurgitation, and from findings at autopsy such as petechiae, we inferred that fatal regurgitation occurred in this PWS infant after tube feeding. Several clinical reports have described milk aspiration, but this pathological report is the first related to aspiration in PWS during tube feeding.

Non-polyalanine repeat mutation in PHOX2B is detected in autopsy cases of sudden unexpected infant death.

BACKGROUND: Congenital central hypoventilation syndrome (CCHS), which is caused by PHOX2B with phenotypic variations, has a point of controversy: CCHS is putatively involved in autopsy cases of sudden unexpected infant death (SUID) including sudden infant death syndrome. OBJECTIVE: The relation of CCHS to SUID cases was investigated by extensive genotyping of PHOX2B. METHODS: We analyzed 93 DNA samples of less than one-year-old SUID cases that were autopsied in our department. Unrelated adult volunteers (n = 942) were used as the control. RESULTS: No polyalanine tract expansion was detected in the SUID cases. The allelic frequencies of repeat contractions and SNP (rs28647582) in intron 2 were not significantly different from that in those control group. Further extensive sequencing revealed a non-polyalanine repeat mutation (NPARM) of c.905A>C in a sudden death case of a one-month-old male infant. This missense mutation (p.Asn302Thr), registered as rs779068107, was annotated to 'Affected status is unknown', but it might be associated with the sudden death. CONCLUSION: NPARM was more plausibly related to sudden unexpected death than expansions because of severe clinical complications. This finding indicates possible CCHS involvement in forensic autopsy cases without ante-mortem diagnosis.

Removal effect of DNA contamination by hydrogen peroxide plasma compared to ethylene-oxide gas.

We examined the ability of hydrogen peroxide plasma (HPP) to remove DNA contamination, to evaluate whether it is a suitable forensic-grade treatment under ISO 18385. HPP treatment was compared to ethylene-oxide gas (EOG) treatment, which is required by ISO 18385. For the evaluation, commercial control DNA solution and cultured cells sprinkled on Petri dishes were used, and the DNA fragments (214 and 80 bp autosomal DNA fragments and 75 bp Y chromosome fragment) were quantified. HPP treatment was performed up to four times and EOG treatment was performed once. Performing HPP treatment three times was as effective as EOG treatment, with all fragments decreasing to below 1/1,000 in DNA solution. With STR and Y-STR typing, no alleles were detected for three HPP treatments of control DNA using the original amount, i.e., 1 ng. Therefore, HPP appears useful for removing DNA contamination. For cells sprinkled on Petri dishes, the DNA degradation abilities of the HPP and EOG were comparable. However, less DNA was degraded with the HPP and EOG and neither met the ISO criteria. Although the current version of ISO 18385 recommends an evaluation method using cultured cells sprinkled on Petri dishes, it needs to be revised. These findings should be considered when revising ISO 18385.

Nonocclusive mesenteric ischemia secondary to spinal cord injury: an autopsy case.

INTRODUCTION: Spinal cord injury (SCI) is a major direct cause of accidental death. Cervical SCI can lead to death in a short time period by neurogenic shock. Prompt vasopressor administration is recommended for patients with SCI accompanied by hypotension (systolic blood pressure < 90 mmHg). We herein present the first fatal case of nonocclusive mesenteric ischemia (NOMI) secondary to cervical SCI in a patient who suddenly died 1 week after an accidental fall. CASE PRESENTATION: A 72-year-old man without medical history of cardiovascular disease suffered tetraplegia with a neurological level at C4 after a fall accident. He was fully conscious with stable respiratory ability, and the systolic blood pressure was maintained at >90 mmHg without vasopressor agents. High fever occurred 7 days after the accident and he died in the next morning. Autopsy revealed segmental intestinal necrosis from the ileum to the ascending colon, without mesenteric embolism, or severe arteriosclerosis. DISCUSSION: This case implies that maintenance of >90-mmHg systolic blood pressure can insufficiently keep the blood flow to prevent NOMI, and the mean arterial blood pressure of >85 mmHg can be more plausible as suggested in the guideline. Monitoring the mean arterial blood pressure in acute SCI is useful not only for neurological recovery but also for the maintenance of vital intestinal perfusion.

Y chromosome analysis for common surnames in the Japanese male population.

For many years of Japan's long history, Japanese surnames have been handed down patrilineally. This study investigated relations between major surnames and Y chromosomal polymorphism among the Japanese male population. To analyze genetic phylogeny in namesakes, the Y-single nucleotide polymorphism (SNP) plus Y-short tandem repeat (STR) approach was employed. A haplogroup based on SNPs and haplotypes at 17 STR loci were typed in 567 unrelated volunteers recruited in Kanagawa, Japan. Samples covered 27 common surnames such as Satoh and Suzuki, each name having 10-55 bearers. Significant difference was found for SNP haplogroup compositions and a multidimensional scaling plot using STR haplotypes in several surname groups. By contrast, these common surnames displayed wide diversity with phylogenetic networks, suggesting that no genetic drift event has occurred in their history. In all, 22 descent clusters were found, as judgcriteria ed by ad hoc of groups within five mutational steps in the 15 STR loci with the same haplogroup. The times of the most recent common ancestor ranged from 279 to over 2577 years. According to the approximate millennium span of Japanese surname history, descent criteria are expected to be reasonable for grouping within four step-neighbors. High heterogeneity of common surnames resembles that observed for England and Spain, but not for Ireland. Our results highlight that common Japanese surnames consist of descent clusters and many singletons, reflecting a mixture of long-term bearers and short-term bearers among the population. The genetic study of this population revealed characteristic features of Japanese surnames.

Cutoff value for hypertrophic heart weight in the Japanese population.

BACKGROUND: Cardiac hypertrophy is a clinical risk factor for cardiovascular death (CVD) frequently recorded in autopsy reports, but the diagnostic criteria for the condition have not been clearly-established for autopsy. This study aimed to estimate the cutoff value for hypertrophic heart weight that can efficiently assist the postmortem diagnosis of CVD. METHODS: We analyzed accumulated autopsy data from 3534 individuals aged 0-101 years. RESULTS: We found that heart weight increased linearly with a person's age until 20 years, after which it remained stable. The mean heart weight in CVD cases was 473 g in men and 379 g in women. The mean heart weight in non-CVD cases was 385 g in men and 320 g in women. Receiver operating characteristic curve analysis for CVD assessment revealed that the cutoff value of heart weight was 407 g (odds ratio of 4.2) in men and 327 g (2.6) in women, and that of heart weight/body height was 2.38 g/cm (4.0) in men and 2.15 g/cm (2.6) in women, respectively. Overall, heart weight was a more useful predictor of CVD in men than in women. In logistic regression analysis, the predictive power of heart weight for CVD was higher than that of body mass index in both sexes. CONCLUSION: Thus, the criteria for hypertrophic heart weight are practical and useful for autopsy recordings, and it can be helpful for postmortem diagnosis of CVD. Our report is the first to reveal the cutoff value for hypertrophic heart weight in the Japanese population.

Jervell and Lange-Nielsen syndrome with novel KCNQ1 and additional gene mutations.

We encountered a boy with Jervell and Lange-Nielsen syndrome (JLNS) with compound heterozygous KCNQ1 mutations, maternal Trp248Phe and a novel paternal mutation, Leu347Arg. His father showed long QT (LQT) and arrhythmia. His mother was asymptomatic with no ECG abnormalities. The proband and his father had an additional mutation (SNTA1 Thr372Met), which is reportedly related to SIDS. These results suggest that multiple gene mutations influence the phenotype of KCNQ1 mutation-related arrhythmia.

Circumstances and factors of sleep-related sudden infancy deaths in Japan.

BACKGROUND: Sudden unexpected death in infancy (SUDI) comprises both natural and unnatural causes of death. However, few epidemiological surveys have investigated SUDI in Japan. OBJECTIVE: This retrospective study was conducted to investigate the latest trends of circumstances and risk factors of SUDI cases in which collapse occurred during sleep. METHODS: Forensic pathology sections from eight universities participated in the selection of subjects from 2013 to 2018. Data obtained from the checklist form were analyzed based on information at postmortem. RESULTS: There were 259 SUDI cases consisting of 145 male infants and 114 female infants with a mean birth weight of 2888 ± 553 and 2750 ± 370 g, respectively. Deaths most frequently occurred among infants at 1 month of age (18%). According to population data as the control, the odds ratio (95% confidence interval) of mother's age ≤19 years was 11.1 (6.9-17.7) compared with ages 30-39. The odds ratio for the fourth- and later born infants was 5.2 (3.4-7.9) compared with the frequency of first-born infants. The most frequent time of day for discovery was between 7 and 8 o'clock, and the time difference from the last seen alive was a mean of 4.1 h. Co-sleeping was recorded for 61%, and the prone position was found for 40% of cases at discovery. Mother's smoking habit exhibited an odds ratio of 4.5 (2.9-5.8). CONCLUSION: This study confirmed the trends that have been observed for sudden infant death syndrome; particularly, very high odds ratios were evident for teenage mothers and later birth order in comparison with those in other developed countries. Neglect was suspected in some cases of the prolonged time to discovery of unreactive infants. To our knowledge, this is the first report of an extensive survey of SUDI during sleep in Japan.

Myocardial cathepsin D is downregulated in sudden cardiac death.

Cathepsins are the major lysosomal proteases that maintain intracellular homeostasis. Herein, we investigated the alterations in myocardial cathepsin expression during aging, cardiac hypertrophy, and sudden cardiac death (SCD). Cardiac tissue and blood were sampled from autopsy cases. Subjects were classified into three groups: SCD with cardiac hypertrophy (SCH), compensated cardiac hypertrophy (CCH), and control. Immunoblotting was performed for the major cardiac cathepsins and their targets: cathepsin B, D, and L (CTSB/D/L), p62, ATP synthase subunit c (ATPSC), and α-synuclein (ASNC). Immunohistochemical analysis and ELISA using serum samples were performed for CTSD. Cardiac CTSB and CTSD were upregulated with age (r = 0.63 and 0.60, respectively), whereas the levels of CTSL, p62, ATPSC, and ASNC remained unchanged. In age-matched groups, cardiac CTSD was significantly downregulated in SCH (p = 0.006) and CTSL was moderately downregulated in CCH (p = 0.021); however, p62, ATPSC, and ASNC were not upregulated in cardiac hypertrophy. Immunohistochemistry also revealed decreased myocardial CTSD levels in SCH, and serum CTSD levels were relatively lower in SCH cases. Overall, these results suggest that upregulation of cardiac CTSB and CTSD with age may compensate for the elevated proteolytic demand, and that downregulation of CTSD is potentially linked to SCH.

MicroRNA profiling of gastric content from breast-fed and formula-fed infants to estimate last feeding: a pilot study.

Recently, we were consulted about a challenging case, where an infant died by poisoning and the drug-dependent mother insisted that she unintentionally gave the toxic drug through breast milk. Accordingly, we investigated the utility of immunoblotting and microRNA (miRNA) profiling of the infant's gastric content (GC) to differentiate between breast-feeding and formula-feeding. As a pilot study, we sampled the GC from breast-fed (GCB) and formula-fed (GCF) infants, as well as gastric juice (GJ) from fasted adults at autopsy. Breast milk (BM) samples were collected from volunteers within 1 year post-delivery. By immunoblotting, lactoferrin and gross cystic disease fluid protein (GCDEP) were clearly detected in BM, but could not be detected in GCB. Similarly, ß-lactoglobulin was detected in formula milk, but could not be detected in GCF. Meanwhile, miRNA sequencing revealed that the miRNA expression profile of GCB was closer to BM than GCF and GJ. Especially, miR-151a and miR-186 were more abundant in BM and GCB than in GCF and GJ. Our study is the first to elucidate the human GJ miRNA profile and demonstrate the possibility that miR-151a and miR-186 in GC may be the biomarker of breast-feeding.

The Impact of Discontinuation of the Medical Examiner System: Cases of Drowning in the Bathtub at Home.

The incidence of death by drowning greatly varies among different prefectures in Japan, mainly due to climate difference. However, there could be other factors affecting the incidence of deaths besides climate, for example, differences in regional death investigation systems. Here, we aimed to elucidate other such factors affecting the mortality data of drowning in the bathtub, especially the effects of discontinuing the medical examiner system. Police data in Kyoto and ambulatory care information in Yokohama were used. Data on cases of elderly individuals found dying or dead in the bathtub at home in winter 2014-2015 were obtained. The following data were collected for each case: age, gender, presence/absence of ambulatory transport, performance of autopsy, and cause of death. The autopsy and drowning rates in Kyoto were 0%, whereas both values in Yokohama were significantly higher at 93.1% and 89.4%, respectively (the denominator of each of the rates is the total number of elderly (aged 65 or over) individuals found dying or dead in the bathtub at home in each city during each winter). Despite no significant difference of incidence of total bath-related death, the proportion of drowning-related deaths was overwhelmingly higher in Yokohama than in Kyoto. The difference can be attributed to the difference in autopsy rates between the two cities, mainly caused by the presence/absence of a medical examiner system. Therefore, we should pay careful attention to future changes in autopsy/drowning rates in Yokohama, and ascertain whether the change might be continuously influenced by the abolishment of this system.