Dynamics of somatostatin 4 receptor expression during chronic-stress loading and its potential as a chronic-stress marker.

Chronic stress has been implicated in mental illnesses and depressive behaviors. Somatostatin 4 receptor (SSTR4) has been shown to mediate anxiolytic and depression-like effects. Here, we aimed to explore the potential of SSTR4 as a diagnostic marker for chronic stress in mice. The mice were divided into single stress, chronic restraint stress, and control groups, and Sstr4 mRNA expression in the pituitary, lungs, and thymus, its protein expression in the thymus, were analyzed. Compared to controls, Sstr4 mRNA expression decreased significantly in the pituitary gland of the chronic and single-stress groups (P = 0.0181 and 0.0022, respectively) and lungs of the single-stress group (P = 0.0124), whereas it significantly increased in the thymus of the chronic-stress group (P = 0.0313). Thymic SSTR4 expression did not decrease significantly in stress groups compared to that in the control group (P = 0.0963). These results suggest that SSTR4 expression fluctuates in response to stress. Furthermore, Sstr4 mRNA expression dynamics in each organ differed based on single or chronic restraint stress-loading periods. In conclusion, this study suggests that investigating SSTR4 expression in each organ could allow for its use as a stress marker to estimate the stress-loading period and aid in diagnosing chronic stress.

Immunohistochemical study of chicken fat clots: Investigation of the formation mechanism.

In forensic practice, the presence of chicken fat clots (CFCs) in the heart and/or large blood vessels of cadavers has been empirically used to estimate the time from the onset of fatal events to death. However, little scientific evidence of its significance exists, and the mechanism of its formation has not been elucidated. CFCs contain large amounts of leukocytes; thus, we hypothesized that leukocytes might contribute to their formation. Since leukocytes, especially neutrophils, are considered to be involved in blood coagulation through the formation of neutrophil extracellular traps (NETs), we aimed to investigate whether NETs are related to the formation of CFCs through immunohistochemistry. Most cells in the CFCs were myeloperoxidase- and neutrophil elastase-positive, strongly suggesting that they were neutrophils. Since chromatin is released extracellularly during NET formation, immunostaining was performed against some types of histones in CFCs. A certain number of neutrophils in CFCs showed positive extra-nuclear and extracellular signals of histones. In addition, citrullination of histone H3, which is considered important for histone release, was immunohistochemically detected in some neutrophils. These results suggest that neutrophils may affect the formation of CFCs through histone release. Although it was not clear how and when citrullination and extracellular release of histones in CFCs occur in this study, our findings provide insights into the events occurring at the time of death in a human body.

Wound age estimation based on chronological changes in chitinase 3-like protein 1 expression.

In forensic practice, wound age estimation is essential for making assessments of injuries; however, it remains challenging, and markers which correctly indicate wound age are required. Since our previous study showed that chitinase 3-like protein 3 (CHI3L3) expression changed chronologically in murine skin wounds, we hypothesized that other proteins of chitinase and chitinase-like protein (C/CLP) family, which CHI3L3 belongs to, might also have varied expression in wound healing. Therefore, we considered that some proteins of the C/CLP family could be used as markers of wound age estimation, and we aimed to test this hypothesis. Examinations of murine skin wounds revealed that the expression of chitinase 3-like protein 1 (CHI3L1) changed chronologically. CHI3L1 expression in human cadaver skin wounds, which was immunohistochemically analyzed by the average ratio of CHI3L1-expressed cells/total cells in 10 microscopic fields, was weak in wounds from days 0 to 1 after injury (0.11 ± 0.024; mean ± standard error of the mean); however, CHI3L1-positive cells appeared in wounds from days 2 to 3 (1.65 ± 0.19). The number of CHI3L1-expressed cells increased in wounds from days 4 to 6 (5.35 ± 0.35) but dropped from days 7 to 13 (1.53 ± 0.24). Receiver operating characteristic curve analysis indicated that wounds from days 4 to 6 after injury could be clearly distinguished from other wounds based on a cutoff value of 2.75, sensitivity of 92.31%, and specificity of 85.14%. Our findings suggest that CHI3L1 could be a reliable marker for wound age estimation in forensic practice.

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.