Establishment of a random forest regression model to estimate the age of bloodstains based on temporal colorimetric analysis.

Bloodstain age estimation is important in forensic science. Although several studies have used spectroscopy to estimate bloodstain ages, this method has not yet been practically applied due to the need for expensive equipment and low reproducibility. Thus, we aimed to develop a bloodstain age estimation model that can be easily performed using a spectrophotometric colorimeter. First, bloodstains were prepared by placing blood obtained from five healthy volunteers on a plastic plate. The bloodstains were kept on conditions with various brightness and temperatures. Then, each bloodstain was dissolved in saline every 24 h to a final concentration of 1%, measured with a spectrophotometric colorimeter, and subjected to machine learning to generate a random forest regression (RFR) model, and finally, the prediction accuracy of the bloodstain age was verified. We also elucidated the mechanism of the color changes utilizing aminoguanidine, which is an inhibitor of Maillard reaction. Finally, we measured the time-dependent color changes of the blood fluids obtained from healthy volunteers and examined if the method could be potentially applied to estimate postmortem interval (PMI). Our results showed that the RFR model estimated the bloodstain age with no substantial assessment, and it was applicable to bloodstains, regardless of the brightness or temperature. The color changes were affected by the addition of aminoguanidine. Furthermore, the method could be applied to blood fluids, suggesting its potential usefulness for PMI estimation. Considering its feasibility, the present method could potentially be introduced to practical forensic sciences in the near future.

Postmortem genetic analysis of 17 sudden cardiac deaths identified nonsense and frameshift variants in two cases of arrhythmogenic cardiomyopathy.

Sudden death, or unexpected natural death of a healthy individual, is a serious problem in all nations. Sudden cardiac death (SCD) mainly due to ischemic heart diseases is the top cause of sudden death. However, there are pathophysiological conditions, referred to as sudden arrhythmic death syndrome, in which no apparent lesion can be identified even after complete conventional or ordinary autopsy. While postmortem genetic analyses have accumulated evidence about underlying genetic abnormality in such cases, the precise relationships between genetic background and the phenotype have been largely elusive. In this study, a retrospective investigation of 17 autopsy cases in which lethal arrhythmia was suspected to be the cause of death was carried out. Genetic analysis focusing on 72 genes reported to be associated with cardiac dysfunctions was performed, in combination with detailed histopathological and postmortem imaging examination, and a family study. As a result, in two cases of suspected arrhythmogenic cardiomyopathy (ACM), we found a nonsense variant in PKP2 and frameshift variant in TRPM4 gene. In contrast, the other 15 cases showed no morphological changes in the heart despite the presence of a frameshift variant and several missense variants, leaving the clinical significance of these variants obscure. The findings of the present study suggest that nonsense and frameshift variants could be involved in the morphological abnormality in cases of SCD due to ACM, while missense variants alone rarely contribute to massive structural changes in the heart.

A case with prolonged headache after COVID-19 vaccination and later developed Bell's palsy.

PURPOSE: During COVID-19 pandemic, the authorization of emergent usage of new vaccine has raised suspicions and doubts about potential adverse events related to vaccination. Among the reported adverse events related to ChAdOx1/nCoV-19 vaccine, facial paralysis did not have an incident rate higher than natural occurrence like mRNA vaccines. However, temporal association between vaccination and facial palsy have been documented in several studies. Here, we report a case of an otherwise healthy 23-year-old Taiwanese female who experienced prolonged headache since the second day postvaccination and developed facial palsy on the tenth day. CASE REPORT: A 23-year-old Taiwanese female who was previously healthy experienced intermittent right side throbbing headache, general malaise, myalgia and fever. Headache, transient ear pain and right scalp numbness developed in the next few days but quickly resolved. On day ten after vaccination, signs of facial palsy on the right side of her face was noticed. The results of brain Magnetic Resonance Imaging (MRI) with contrast displayed no abnormality. Facial stimulation and blink reflex tests were compatible with right facial neuropathy. CONCLUSION: Reactivation of latent herpes virus has been suggested as one of the possible mechanisms underlying the phenomenon, but the causal pathophysiology related to the symptom needs further validation. Moreover, in the event of facial palsy post-vaccination, alternative diagnoses such as Guillain-Barre syndrome (GBS), Ramsey-Hunt syndrome, Lyme disease, trauma, central nervous system infection (CNS) infection, or stroke should also be considered.

Development of a detector tube for screening tadalafil and its analogues in adulterated sexual enhancement products.

Sexual enhancement products adulterated with phosphodiesterase 5 inhibitors (PDE-5i) pose a serious public health concern. Tadalafil and its analogues (Tds) are PDE-5i frequently detected as adulterants. In this study, a Td detector tube for the rapid detection of Tds was developed based on the color change reaction between sulfuric acid and Tds. The specificity of this test method was evaluated using 13 Tds, all of which elicited positive results. Additionally, 30 commonly found adulterants in dietary supplements, 11 active pharmaceutical ingredients of psychotropic drugs and 18 food ingredients were tested and obtained no false-positive results, except levomepromazine. The test tube accurately detected the presence or absence of Tds in 54 commercially available products. The visual detection limit was 2-50 and 5-20 µg/ml for Tds and tadalafil-spiked samples with matrix, respectively. The applicability of the developed detector tube to a semiquantitative test using digital image analyses were investigated using red, green, and blue color values. The results of the recovery test suggested that the tube test was affected by the dark-colored matrix. The results of semiquantitative analyses of tadalafil for five marketed products were consistent with the liquid chromatographic quantification results, except for the blue value. The detector tube developed in this study can facilitate with the rapid screening of Tds in adulterated sexual enhancement products.