TY  - JOUR
PY  - 2021//
TI  - Experimental water injection into lungs using an animal model: verification of the diatom concentration test to diagnose drowning
JO  - Forensic science international
A1  - Kihara, Yuko
A1  - Makino, Yohsuke
A1  - Nakajima, Makoto
A1  - Tsuneya, Shigeki
A1  - Tanaka, Aki
A1  - Yamaguchi, Rutsuko
A1  - Torimitsu, Suguru
A1  - Hayama, Shin-Ichi
A1  - Iwase, Hirotaro
SP  - e110983
EP  - e110983
VL  - 327
IS  - 
N2  - BACKGROUND: In forensic medicine, the diatom test is used to diagnose drowning. Drowning and postmortem immersion can be distinguished by calculating the ratio of diatom concentration in the lungs and drowning water (L/W ratio). However, this claim was based on the unproven hypothesis that diatoms may be concentrated in the lungs due to respiratory movements. This study was conducted to examine whether the L/W ratio increased with experimental water injection. <br><br>METHODS: A total of two experiments was performed using 22 non-drowned cat carcasses found on dry land. First, for the experimental postmortem immersion, we soaked seven whole-body cat carcasses in pond water for an hour. Second, the pond water was experimentally injected one or ten times into each harvested lung from seven and eight cats, respectively. In the diatom test, two diatom species (Aulacoseira ambigua and Discostella asterocostata) that were dominantly observed in pond water as well as other diatom species were counted separately. The L/W ratios of each cat were calculated. Univariate linear regression analysis was performed to demonstrate the association among L/W ratios and the three categories of the experiments. The L/W ratios of the two experiments were compared with those of drowning or postmortem immersion cases of humans or cats. <br><br>RESULTS: It was revealed that the clear L/W ratio differences between the three groups (experimental postmortem immersion<0.02, 1-injection < 0.2, 10-injection > 0.9 for all diatom counting) were with statistically significant as proven by the univariate regression analyses. In actual cases of cats and humans, L/W ratios were>0.4 for drowning and<0.04 for postmortem immersion. <br><br>CONCLUSION: The L/W ratio increased with multiple experimental water injections into the lungs, thereby verifying the validity of the diatom concentration test to diagnose drowning. The diatom test can be used to distinguish between drowning and postmortem immersion in humans and cats by calculating the L/W ratio.<p />  <p>Language: en</p>
LA  - en
SN  - 0379-0738
UR  - http://dx.doi.org/10.1016/j.forsciint.2021.110983
ID  - ref1
ER  -