Development of age-estimation formula using postmortem oral findings: A pilot study.

The goal of this pilot study was to develop an age-estimation formula and assess its effectiveness after evaluating individual intraoral findings. A total of 198 Japanese adults were included, and intraoral findings were collected from the corpses. To analyze the condition of each tooth, 20 items were established for intraoral findings, and seven tooth states were established. Logistic regression analysis was used to estimate the impact of age on each intraoral finding. Sequentially, linear regression was applied to verify the correlation between age and type of tooth, and multiple regression was used to correlate age-dependent factors. The intraoral findings with age dependency were tooth stump, edentulous jaw, attrition, no caries, dental prostheses, partial dentures, and complete dentures. Tooth stump, attrition, and dental prostheses showed positive multicollinearity. Missing tooth, extant tooth, normal teeth, and untreated lost teeth were age-correlated. Multiple regression analysis included age as the response variable and five factors as the explanatory variables in a new age-estimation formula, resulting in ± 10 years for 86.96% of cases (60-69 years old), 76.47% (70-79 years old), and 61.05% of all cases. The multiple correlation was 0.551, and the contribution rate of the multiple regression formula was 0.304. The accuracy of the proposed age-estimation formula was within ± 10 years for 61.05% of all subjects. However, the accuracy of age estimation in subjects aged 60-79 years was excellent (76.47-86.96%), which showed that this age-estimation formula would be effective for estimating the age of middle-aged to older subjects.

Accurate interpretation of genetic variants in sudden unexpected death in infancy by trio-targeted gene-sequencing panel analysis.

In sudden unexpected death in infancy cases, postmortem genetic analysis with next-generation sequencing potentially can extract candidate genes associated with sudden death. However, it is difficult to accurately interpret the clinically significant genetic variants. The study aim was to conduct trio analysis of cases of sudden unexpected death in infancy and their parents to more accurately interpret the clinically significant disease-associated gene variants associated with cause of death. From the TruSight One panel targeting 4813 genes we extracted candidate genetic variants of 66 arrhythmia-, 63 inherited metabolic disease-, 81 mitochondrial disease-, and 6 salt-losing tubulopathy-related genes in 7 cases and determined if they were de novo or parental-derived variants. Thirty-four parental-derived variants and no de novo variants were found, but none appeared to be related to the cause of death. Using trio analysis and an in silico algorithm to analyze all 4813 genes, we identified OBSCN of compound heterozygous and HCCS of hemizygous variants as new candidate genetic variants related to cause of death. Genetic analysis of these deceased infants and their living parents can provide more accurate interpretation of the clinically significant genetic variants than previously possible and help confirm the cause of death.

Body temperature-dependent microRNA expression analysis in rats: rno-miR-374-5p regulates apoptosis in skeletal muscle cells via Mex3B under hypothermia.

Forensic diagnosis of fatal hypothermia is considered difficult because there are no specific findings. Accordingly, exploration of novel fatal hypothermia-specific findings is important. To elucidate the molecular mechanism of homeostasis in hypothermia and identify novel molecular markers to inform the diagnosis of fatal hypothermia, we focused on microRNA expression in skeletal muscle, which plays a role in cold-induced thermogenesis in mammals. We generated rat models of mild, moderate, and severe hypothermia, and performed body temperature-dependent microRNA expression analysis of the iliopsoas muscle using microarray and quantitative real-time PCR (qRT-PCR). The results show that rno-miR-374-5p expression was significantly induced only by severe hypothermia. Luciferase reporter assay and qRT-PCR results indicated that Mex3B expression was regulated by rno-miR-374-5p and decreased with decreasing body temperature. Gene ontology analysis indicated the involvement of Mex3B in positive regulation of GTPase activity. siRNA analysis showed that Mex3B directly or indirectly regulated Kras expression in vitro, and significantly changed the expression of apoptosis-related genes and proteins. Collectively, these results indicate that rno-miR-374-5p was activated by a decrease in body temperature, whereby it contributed to cell survival by suppressing Mex3B and activating or inactivating Kras. Thus, rno-miR-374-5p is a potential supporting marker for the diagnosis of fatal hypothermia.

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.