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.

[The succession of the Hippocratic corpus in modern Greece].

This paper examines how the Hippocratic corpus was passed on during the Enlightenment of modern Greece, introducing part of the latest Greek research on the history of medicine. Although classical studies at large had stagnated at the time under the rule of the Ottoman Empire, with the movement toward independence in the second half of the 18th century the Greeks raised their consciousness of the fact that they were the successors to their ancestral great achievements. From that time classical studies, including the history of medicine, had been activated. From some medical dissertations and books written by Greek doctors or researchers of those days, we will recognize that they made efforts to deepen the substance of modern Greek medicine, seeking the principles of medical practice from the ancient heritage.

Severe Cardiac Rupture by Only One Blow to the Chest in a Young Boy: An Autopsy Case.

Cardiac rupture by blunt chest trauma is commonly seen after motor vehicle accidents and falls; however, it is rarely caused by a blow to the chest. We herein report an autopsy case of a high school boy who sustained severe right ventricular rupture by only one knee kick to the chest during a quarrel. He was hospitalized and developed cardiopulmonary arrest. Emergency surgery was performed, but the patient died. The autopsy revealed no external severe trauma or deformation, but the side wall of the right ventricle contained a large V-shaped laceration. The other thoracic organs had no injuries. This case illustrates that severe cardiac rupture can occur by only one blow to the chest. Blunt cardiac injuries can occur even if no severe injuries are present on the body surface. We should consider the possibility of severe cardiac injuries regardless of the presence of external injuries.

DNA extraction for short tandem repeat typing from mixed samples using anti-human leukocyte CD45 and ABO blood group antibodies.

DNA testing from mixed cell samples can be difficult to use successfully in criminal investigations. Here, we present a method for the extraction of DNA from mixed bloodstains involving plural contributors, after antibody-microbead captured cell separation. This method, together with the multiplex short tandem repeat typing presented, has proven highly successful in the recovery of DNA profiles corresponding to the ABO blood type. Methodological steps include magnetic separation using leukocyte specific CD45 antibody-coated microbeads and centrifugal separation of leukocyte agglutination by ABO antibody. The detection results of variable mixed ratio showed that the target DNA was detected accurately as low as 1:512 mixed ratio, regardless of the large amount of the background DNA present. The method presented here is applicable to PCR-based identification for various kinds of mixed samples.

Application of a novel multiplex polymerase chain reaction system for 12 X-chromosomal short tandem repeats to a Japanese population study.

The analysis of X-chromosomal short tandem repeat (X-STR) polymorphisms has been the focus of attention in several researches, mainly due to its applicability in the investigation of complex kinship cases. A new 12 X-STR multiplex system (GATA172D05, DXS7423, DSX6809, DXS10134, DXS7132, DXS9902, DXS6789, DXS10074, DXS8378, DXS9898, DXS10147, and GATA31E08) was developed and applied to a Japanese population study. DNA samples from 290 males and 160 females were successfully analyzed using the 12 X-STR multiplex system. No mutation was detected in the kinship cases involving 34 family trios. The combined powers of discrimination of the 12 X-STR loci in males and females were 0.999997 and 0.9999999996, respectively. We conclude that the combined analysis of 12 X-STR loci using this single multiplex polymerase chain reaction system is a powerful tool in forensic DNA testing.

Vanadium accelerates polymerase chain reaction and expands the applicability of forensic DNA testing.

Polymerase chain reaction (PCR) has been rapidly established as one of the most widely used techniques in molecular biology. Because most DNA analysis is PCR-based, the analysis of unamplifiable DNA of poor quality or low quantity is nearly impossible. However, we observed that if an appropriate concentration of vanadium chloride is added to the standard reaction mixture, the enzymatic amplification of DNA could be enhanced. Using multiplex PCR with the addition of vanadium, DNA typing was possible from even trace amounts of DNA that we were unable to amplify using normal reaction conditions. This method might be an effective tool for not only criminal investigations and ancient DNA analysis, but also for nearly all fields using DNA technology.