The persistent problem of drowning - A difficult diagnosis with inconclusive tests

Diatoms pass through the gastrointestinal barrier and lead to false-positive: an animal experiment

The diatom test has been used by forensic pathologist as standard for drowning, but the occurrence of false-positive results (presence of diatoms found in the tissues of subjects who died from causes other than drowning) draws criticism regarding the specificity of the test. Diatoms within food or water can be ingested through the gastrointestinal tract. However, the mechanisms of how the diatoms reach distant organs such as the lung, liver, and kidney have not been studied. In this article, we simulated the process of diatoms entering the gastrointestinal tract using gastric lavage on experimental rabbits. Diatoms are detected in lymph from a lymphatic vessel at the root of the mesentery, portal vein blood, aortic blood, lung, liver, and kidney samples in the gavage group. Of diatoms, 76.24% were the centric diatom, 99.86% of diatoms have a maximum size of less than 50 µm, and most of diatoms concentrate in the lung. Our study provided the evidence supporting the theory that the diatoms could pass through the gastrointestinal barrier and reach the rabbits' other internal organs. The diatoms could reach internal organs through the portal vein and lymphatic vessel at the root of the mesentery. This provides us new insight into our understanding of false-positive diatom test in forensic pathology.

The death of Rasputin-A forensic evaluation

Grigori Yefimovich Rasputin, a confidant of Tsar Nicholas and his wife, was murdered by Prince Yussupov and his co-conspirators in the cellar of the prince's Moika Palace in St Petersburg, Russia, on the evening of December 30th, 1916 (December 17th in the Russian calendar). The narrative of his death is largely based on Prince Yussupov's published memoirs and has Rasputin being poisoned with cyanide, shot, bludgeoned, and finally drowned. A review of the available forensic material, however, shows a photograph with a contact gunshot wound to Rasputin's forehead. This would indicate that he was dead prior to being dropped into the Little Nevka River. His distaste for sweet foods and the absence of poison at autopsy would also suggest that the story of cyanide toxicity was fabricated. Yussupov's description of Purishkevich firing at Rasputin from a distance as he ran across the courtyard in an attempt to escape would also not be consistent with the post mortem photograph. The simplest version of the events would be that Rasputin was executed by a contact gunshot wound to the forehead when he visited the Yussupov Palace. While it appears that the events of that fateful evening have been embellished, it is certainly not uncommon for perpetrators of homicides to provide histories that are later shown to be at odds with the truth. Re-evaluation of historic cases may provide compelling evidence for alternative interpretations to the popular historic record.

A comparative assessment of time-consuming and laborious diatom analysis：Brief experimentation with suggestion of automatic identification

Diatom testing is considered a useful method for providing supportive evidence for the diagnosis of drowning in forensic pathology. However, various factors remain controversial for recognizing diatoms, such as being time-consuming and laborious and influencing the consistency of the results. Given the absence of precise and well-defined studies on this subject, this study aimed to determine the relationship between the ability to identify diatoms and researchers with different technical backgrounds. A total of 55 samples from 18 cases, including water, lungs, liver, and kidneys, were treated using the microwave digestion-vacuum filtration-automated scanning electron microscopy (MD-VF-Auto SEM), which was used to compare diatom analyses among three groups of well-trained forensic pathologists (FPs), trained junior employees (JEs), and new trainees (TEs). In addition to achieving similar accuracy of positive findings from drowning cases, counting efficiency was evaluated based on taxonomy records and counting time after viewing more than 5500 diatom images. In contrast to the higher counting efficiency of the JE group than that of the TE group, we observed a statistically significant difference (p < 0.05) in the diatom classification between these two groups. Based on our experiments, an efficient analysis for automatically identifying and classifying diatoms is urgently required.

The role of paranasal sinus fluid in determining drowning as the cause of death: A systematic review and meta-analysis

Drowning is a significant global cause of unintentional injury fatalities, and accurate forensic diagnosis of drowning remains a challenge due to the nonspecific nature of post-mortem findings obtained through classical autopsy methods. Our manuscript addresses this issue by focusing on the emerging use of paranasal sinus fluid as a valuable tool in determining the cause of death, specifically in distinguishing drowning from non-drowning cases. The study provided a comprehensive summary of available evidence from observational studies that compared findings in the paranasal sinuses between drowning and non-drowning victims, analyzing parameters such as the presence of fluid, fluid volume, and density. The study encompassed a total of 14 selected studies involving 1044 subjects and utilized rigorous risk of bias assessment and data synthesis techniques. The meta-analysis demonstrated a strong association between the presence of fluid in the paranasal sinuses and drowning (OR = 17.1; 95% CI 7.2 to 40.5; p < 0.001). In addition, drowning victims had a significantly greater volume of fluid (SMD = 0.8; 95% CI 0.5 to 1.2; p < 0.001) and lower fluid density (SMD = -1.4; 95% -2.5 to -0.4; p = 0.008) compared to non-drowning cases. The results support the utility of paranasal sinus fluid analysis as a valuable diagnostic method in cases where drowning is suspected but cannot be definitively confirmed through traditional approaches.

Influence of the toxicological status on the diagnosis of fatal drowning

Drowning is the leading cause of death by accident of everyday life in people under 25 years of age. Xenobiotics are frequently involved in drowning cases but their influence on the diagnosis of fatal drowning has not been studied so far. This preliminary study aimed to assess the influence of an alcohol and/or a drug intoxication on the autopsy signs of drowning, and on the results of diatom analyses in drowning deaths. Twenty-eight autopsy cases of drowning including 19 freshwater drownings, 6 seawater drownings, and 3 brackish water drownings were prospectively included. Toxicological and diatom tests were performed in each case. The influence of alcohol and other xenobiotics on drowning signs and diatom analyses was assessed separately then in combination through a global toxicological participation score (GTPS). Diatom analyses showed positive results in lung tissue in every case. No significant association was found between the degree of intoxication and the diatom concentration in the organs, even after considering freshwater drowning cases only. The vast majority of the traditional autopsy signs of drowning were not significantly affected by the individual toxicological status either, with the exception of lung weight which tended to raise in case of intoxication, probably due to the pulmonary edema and congestion increase. Further research on larger autopsy samples is needed to confirm the results of this exploratory study.

Emerging issues in the approach to submerged bodies: Water-related deaths in Friuli, northeastern Italy (1993-2020). Analysis of post-mortem reports and some unusual cases

When analysing bodies recovered from a watery environment, all manners of death, a variety of causes of death and the possibility of body disposal have to be considered. Unclear circumstances of death, unidentified victims and body decomposition may hamper a forensic investigation. The lack of specific and sensitive drowning-related autopsy findings and post-mortem blood alcohol levels (blood alcohol concentrations (BACs)) may also lead to erroneous conclusions. We reviewed the autopsy records for all bodies recovered from water in Friuli, northeastern Italy, over a 28-year period, focusing on death circumstances, autopsy findings and blood alcohol levels. Some unusual cases were examined separately. Among the 69 cases, there were 32 accidents, 13 suicides, 4 homicides, 6 natural and 14 undetermined deaths. Causes of death included 51 drownings, 6 undetermined, 5 cardiac deaths and 7 non-drownings. Six deaths in a bathtub and one diving-related death were also included. Acute alcohol intoxication was ascertained in 22 of 40 victims. Some significant limitations in the approach to water-related deaths have been highlighted: although emphysema aquosum and external foam resulted to be the most reliable indicators, a determination of drowning based exclusively on autopsy findings cannot be ascertained with certainty. Furthermore, it was found that the standard definitions of wet and dry drowning in the literature differ widely from a morphological perspective and this may lead to misleading outcomes. Post-mortem BAC changes have been critically analysed only in bodies found in cold water, and, in the absence of an alternative to blood specimens, the use of pre-set cut-off values is still necessary.

DiatomNet v1.0: A novel approach for automatic diatom testing for drowning diagnosis in forensically biomedical application

BACKGROUND AND OBJECTIVE

Diatom testing is supportive for drowning diagnosis in forensic medicine. However, it is very time-consuming and labor-intensive for technicians to identify microscopically a handful of diatoms in sample smears, especially under complex observable backgrounds. Recently, we successfully developed a software, named DiatomNet v1.0 intended to automatically identify diatom frustules in a whole slide under a clear background. Here, we introduced this new software and performed a validation study to elucidate how DiatomNet v1.0 improved its performance with the influence of visible impurities.

METHODS

DiatomNet v1.0 has an intuitive, user-friendly and easy-to-learn graphical user interface (GUI) built in the Drupal and its core architecture for slide analysis including a convolutional neural network (CNN) is written in Python language. The build-in CNN model was evaluated for diatom identification under very complex observable backgrounds with mixtures of common impurities, including carbon pigments and sand sediments. Compared to the original model, the enhanced model following optimization with limited new datasets was evaluated systematically by independent testing and random control trials (RCTs).

RESULTS

In independent testing, the original DiatomNet v1.0 was moderately affected, especially when higher densities of impurities existed, and achieved a low recall of 0.817 and F1 score of 0.858 but good precision of 0.905. Following transfer learning with limited new datasets, the enhanced version had better results, with recall and F1 score values of 0.968. A comparative study on real slides showed that the upgraded DiatomNet v1.0 obtained F1 scores of 0.86 and 0.84 for carbon pigment and sand sediment, respectively, slightly worse than manual identification (carbon pigment: 0.91; sand sediment: 0.86), but much less time was needed.

CONCLUSIONS

The study verified that forensic diatom testing with aid of DiatomNet v1.0 is much more efficient than traditionally manual identification even under complex observable backgrounds. In terms of forensic diatom testing, we proposed a suggested standard on build-in model optimization and evaluation to strengthen the software's generalization in potentially complex conditions.

Forensic application of aquaporins

Aquaporins (AQPs) are a family of water channel proteins that primarily elicit the basic functions of water transport and osmotic homeostasis. To date, at least 17 mammalian AQPs have been identified, AQP-0 to -12 have been found in higher orders including human, and AQP-13 to -16 have been described in older lineages. Moreover, these proteins have recently been shown to regulate many biological processes through unique activities, such as cell proliferation, migration, apoptosis, and mitochondrial metabolism. Several studies have focused on the involvement of AQPs in cell biology aspect, showing that they are involved in a variety of physiological processes and pathophysiological conditions. Furthermore, in the field of forensic medicine, studies on whether AQPs can be a useful marker for diagnosing various causes of death have been conducted using autopsy samples and animal experiments, which have produced interesting results. Herein, we review certain observations regarding AQPs and discuss their potential to contribute to the future practice of forensic research.

Relevance of diatom testing on closed organs of a drowned cadaver who died after receiving treatment for 10 days: A case report

A male in his late adolescence fell into the sea and was found 50 min later with cardiopulmonary arrest. He was revived approximately 260 min after he drowned. Although he received several treatments, including venoarterial extracorporeal membrane oxygenation and continuous hemodiafiltration, he was clinically diagnosed with brain death. He died 10 days after the accident. The autopsy did not reveal any unremarkable findings other than those associated with post-resuscitation changes and medical treatment. The diatom test revealed 47.9, 311.6, and 577.5 diatom particles per gram from water, left lung, and right lung samples, respectively. No diatoms were detected in a 10 g liver sample, and 1 diatom was detected in each of approximately 12 g of bilateral kidney samples, which was different from the abundant species in the lung samples. The diatom test of the closed organs could be considered false negative for confirming drowning death since diatoms can also be detected in non-drowned cadavers on dry land. This suggests that diatoms might not reach the closed organs via circulation and that the diatom test of closed organ samples might no longer be necessary to confirm drowning deaths.

The epidemiology, risk factors and impact of exposure on unintentional surfer and bodyboarder deaths

Surfing and bodyboarding (SAB) are popular activities, but not without risk. Limited SAB mortality and exposure risk explorations exist, so this cross-sectional study explores epidemiology and risk factors for SAB deaths (1 July, 2004-30 June,2020) in Australia: including decedent and incident profiles, causes of death, differences between fatalities during SAB and other coastal activities; and the impact of exposure on SAB mortality risk. Fatality data were sourced from the National Coronial Information System, incident and media reports. Tide-state data, population data and participation data were sourced from relevant authorities. Analyses included chi-square testing and simple logistic regression with odds ratios. There were 155 SAB deaths (80.6% surfing; 96.1% male; 36.8% aged 55+years; 0.04/100,000 residents; 0.63/100,000 surfers). Drowning was the most common cause of death (58.1%; n = 90), but higher in bodyboarding, with bodyboarders 4.62 times more likely to drown than surfers (95%CI: 1.66-12.82; p = 0.003). Almost half (44.5%; n = 69; χ22 = 9.802; p = 0.007) were with friends/family, and the largest proportion occurred during a rising tide (41.3%; n = 64; χ23 = 180.627; p<0.001) followed by a low tide (36.8%;n = 57). Australians surf 45.7 times each year, for 1.88 hours each visit equalling 86.1 'exposed' hours. With exposure-time considered, exposure-adjusted surfer mortality rate (0.06/1 million hours) is lower than other in-water activities (0.11/1 million hours). Younger surfers (14-34 years) surfed more yet had the lowest mortality rate (114.5 hours/year; 0.02/1 million hours). Older surfers (55+ years) had a lower SAB mortality rate (0.052) than the all-cause crude mortality rate of their average population counterparts (1.36). Cardiac conditions were identified in 32.9% (n = 69) of SAB deaths. SAB are relatively safe, with lower exposure mortality rates than other activities. Prevention should target older surfers, inland residents, and identification of surfers with risk factors for cardiac events.

Use of cadaveric vitreous humor as an innovative substrate for diatoms research and forensic diagnosis of drowning

The search for diatoms is the test that most of all may contribute to the forensic diagnosis of drowning. Diatoms can be extracted through different methods, which are all complex and long. In this preliminary study, we assessed human vitreous humor as an innovative substrate on which to research diatoms. Sampling and analyses were performed on 3 groups of 10 corpses each. The first one was composed of drowned victims. The second one of victims of traffic accidents with subsequent projection in water; based on the severe traumatic injuries reported at autopsy, we considered such victims as ideally assimilable to bodies immersed in water postmortem. The third group was composed of subjects who died for natural causes and without any relationship with water. The vitreous humor was centrifugated and cytocentrifuged and spotted on two different histological slides: one was left blank and the other one was assessed with hematoxylin and eosin staining. Microscopic observation successfully revealed diatoms in all cases of the first group; in the second group diatoms were not detected in 6 cases; in the third group, no diatoms at all were observed. Diatoms were always qualitatively and quantitatively consistent with those found in the corresponding viscera and waters, which had been investigated through classical acid digestion. Our analyses have demonstrated that the vitreous humor behaves in a completely similar way to the other viscera in cases of drowning. Although further investigations are necessary, vitreous humor has proved to be an innovative, suitable, and reliable substrate for the forensic research of diatoms.

Epidemiology and autopsy findings of 500 drowning deaths

INTRODUCTION

Drowning is a significant public health problem worldwide and the WHO reported that drowning is the world's third leading unintentional injury death. Nevertheless, there is still uncertainty regarding the estimate of local and global drowning deaths. In addition, the postmortem diagnosis of drowning is challenging and the physiological mechanisms of death by drowning are complex and not very well understood.

PURPOSE

To analyze a large series of bodies retrieved from the water in Connecticut (U.S.) in order to compare epidemiologic and toxicological data with those of the literature, as well as to examine the weights of the lungs and brains in drowning deaths.

MATERIAL AND METHOD

We conducted a descriptive, retrospective, population-based analysis of all bodies retrieved from the water and subjected to a forensic autopsy at the Office of the Chief Medical Examiner in Connecticut (2008-2020, n = 500). Variables collected were sex, age, date of death, location of drowning, season, type of water, cause of death, manner of death, circumstances of death, signs of decomposition, BMI, brain weight, lung weight, presence of pulmonary edema, stomach contents, and toxicological analysis.

RESULTS

The death rates of drownings in Connecticut ranges from 0.75 to 1.28/100,000/year. They occurred predominantly in males (73.4%) and most were accidents (75.6%), though this gender difference diminishes in suicides (55.4% of males). Sex distribution is also different in bathtub drownings, where women drown more frequently (67.3%). Weights of the brains (p = 0.013) and lungs (p < 0.001) were higher in saltwater drownings.

CONCLUSIONS

Drowning is more frequently an accident involving men, except for suicides where there is only a slight difference among sex. Heavy lungs and cerebral edema continue to be identified in numerous drowning deaths. These anatomic findings, however, must still be interpreted in the context of the entire case investigation. Weights of the brains and lungs are higher in salt water, although these organs' weights are mostly dependent on other variables such as BMI and decomposition.

Sternal aspirate sampling of Bacillariophyceae (diatoms) and Cyanobacteria in suspected drowning cases

A diagnosis of drowning is not always possible based on the traditional autopsy findings. The most widely used ancillary methods are based on the detection of diatoms and other waterborne organisms in the organs of the systemic circulation by light microscope or polymerase chain reaction (PCR). One of the greatest concerns is sample contamination. Bone marrow is a favourable source because the compact bone protects the sample from water ingress in the case of advanced decay. In our pilot study, we aimed to adopt sternal bone marrow aspiration - which is a widely used technique in haematology - for postmortem sampling. Control experiments of non-drowning victims showed that cleaning the skin over the sternum can prevent external contamination. Sternal aspirate samples were taken from seven suspected drowning victims along with lung, spleen, and femoral bone marrow samples. All specimens were examined for the presence of diatoms by light microscope and Cyanobacteria-specific DNA by PCR. We were able to obtain bone marrow aspirates from all cases without complications. In four of the sternal samples both diatoms and cyanobacterial DNA were detected, while one additional sternum sample was tested positive with PCR, but no diatom shells were detectable. Sternal bone marrow aspiration is simple and quick, which can be performed at the beginning of an autopsy, minimizing the chance of contamination. We have shown that this sampling method can be adopted for postmortem diatom testing. This minimally invasive technique might be used in virtual autopsy (postmortem computed tomography, PMCT) settings without opening body cavities.

Relationships between Diatom Abundances in Rat Organs and in Environmental Waters

OBJECTIVE

A diagnosis of drowning remains one of the most challenging issues in forensic science, especially for decomposed bodies. Diatom analysis is considered as an encouraging method for diagnosing drowning. In this study, we developed a drowned rat model using different diatom densities in water.

METHODS

A total of 120 adult Sprague-Dawley rats were used and divided into six groups, wherein experimental groups 1-5 were drowned rats (group A) and postmortem submersion rats (group B) that were submerged in water with five different Cyclotella sp. diatom densities, while the remaining group was used as a blank control. The combination of microwave digestion and vacuum filtration method was used to accomplish efficient tissue digestion and ascertain higher accuracy of diatom determinations within organs.

RESULTS

The abundances of diatoms in the lungs, livers, and kidneys were significantly different. The diatom abundances in the lungs, livers, and kidneys were directly proportional to the water diatom densities, and specific quantitative relationships could be approximated by separate regression equations for each organ type. However, the trends associated with the diatom increases among organs slightly differed. In addition, the diatom abundances in the lungs, livers, and kidneys were all positively correlated. Diatoms were not observed in the postmortem submersion groups nor in the blank control groups.

CONCLUSION

The results of this study provide valuable information for establishing a quantitative diatom framework for informing future forensic medicine efforts.

Trace elements in forensic human lung: A new approach to the diagnosis of seawater drowning. A preliminary study

The diagnosing of drowning remains one of the most challenging activities for the forensic pathologist. There is little information on the impact on the lung as a target organ in death by drowning. We aimed to investigate the concentration of trace elements in the lungs of people who had suffered different types of death to evaluate the discriminating ability of trace elements to identify seawater drowning (SWD). A total of 11 trace elements were analyzed by Inductively Coupled Plasma-Mass Spectrometry in 74 forensic cases. Sampler scanning electron microscopy and Energy Dispersive X-ray spectroscopy (EDX) were used to identify ultrastructural lung alterations. A Principal Component Analysis (PCA) of trace elements was carried out. The trace elements in SWD lungs were detected in the following order of concentration: Br˃Zn˃Sr˃Cr˃Cu˃As˃Pb˃Se˃Mn˃Ni˃Cd. Our results showed significantly higher concentrations of Br and Sr (P = 0.010 and P = 0.000) and significantly lower concentrations of Zn, Pb, Cu, Cd, and Se in SWD compared with other causes of death. After adjusting by confounder factors, Sr and Br remained as predictive independent factors for diagnosis of drowning (p = 0.042, in both cases). These results were confirmed by PCA, which revealed a wide separation between SWD and the rest of the causes of death. Our SWD cohort was characterized by high concentrations of the trace elements Br and Sr and low concentrations of Zn, Pb, Cu, Cd, and Se in lung tissue, while PCA showed its discriminatory capacity to identify death by seawater drowning. These findings, together with those obtained using other techniques, can be of great importance in the diagnosis of SWD.

Fatal coastal drowning incidents: A 10-year review of body recovery times in New Zealand

Despite drowning being a leading cause of unintentional injury worldwide, gaps in the data still exist. One area where limited data is available to guide lifeguards, police, search and rescue agencies, accident and forensic investigators, ocean scientists, and the coroner, is how far from the last known point (displacement) a missing person is likely to be found, and the time frame for this to occur. This lack of certainty can exacerbate the emotional toll on family, friends, and rescuers. This study aimed to describe body recovery times and displacement for fatal coastal drowning incidents in New Zealand. Using DrownBase™, the National Coronial Information System, and media reports, data were extracted for all fatal coastal-missing-person drowning incidents from 2008 to 2017. A total of 219 cases were selected. Almost all incidents involved males (92%) and minority groups (e.g., Māori and Pasifika) were over-represented. Older adults (> 42 years) were more likely to be engaged in boating, whereas for younger adults (≤ 42 years), it was swimming. Most missing persons were described as good swimmers (51%) and wearing everyday clothing (48%), yet only 4% wore a lifejacket. Most incidents were observed (63%), and rescue was attempted in 86% of cases. Most bodies (58%) were recovered within 24h, and only 15% were not found (9%) or not reported (6%). Most missing persons (64%) were either found in the same location (57%) or <1km from where they entered the water (7%). The quality of on-scene data limited some analysis, and the results of this study may not apply to all aquatic locations. Improved data collection could inform real-time predictive modelling of where and when a missing person might be found. The involvement of forensic and ocean scientists in future study design to widen applicability to these domains is also recommended. Fewer lives would be lost to drowning, however, if safer practices were adopted when recreating or working in, on, or around water.

Development of 18S rRNA gene arrays for forensic detection of diatoms

Diatom test is the most commonly used method to diagnose drowning in forensic laboratories. However, microscopic examination and identification of diatom frustules is time-consuming and requires taxonomic expertise. At present, the identification of drowning is still a challenge in forensic casework. In this study, we developed a novel diatom microarray based on the detection of specific 18S rRNA gene fragments of diatom species. The array covers 169 diatom species which were documented as commonly found in a wide range of fresh waters in China. Diatom arrays were prepared from species specific oligonucleotide probes targeting to variable regions of the 18S rRNA gene. We also developed an auxiliary sample preparation method for isolation of diatom DNA from tissues, which enabled detection of diatom species in real forensic samples as well as environmental waters. We applied the diatom arrays to analyze six drowned cases and eight environmental samples. The diatom arrays showed much better sensitivity and more consistent results than those of the conventional SEM methods. We discovered major discrepancies between results generated by the diatom arrays and the routinely used SEM based diatom tests. We verified the results of our diatom arrays by species specific PCR and Sanger sequencing and found that the currently used SEM diatom test method has a serious deficiency in sensitivity due to high loss rate of frustules in the sample preparation procedure. We anticipate that the application of diatom arrays will transform current forensic practice of diagnosing drowning deaths.

Characteristics of drowning deaths in an inner city river

A study was undertaken of all drowning deaths that occurred over a 30-year period from 1988 to 2017 in the urban section of the River Torrens, Adelaide, South Australia, an augmented waterway that runs through the central business district. Autopsy records from Forensic Science South Australia (FSSA) were reviewed. There were 34 drownings (0-5 cases/yr) with 28 males and 6 females (M;F = 4.6:1), with an age range for males of 18-76yrs (mean 42.0; SD 18.0) and for females of 20-84yrs (mean 69.3; SD 24.5). There were 15 (44%) accidents, 11 (32%) suicides, 1 (3%) homicide and 7 (21%) undetermined. Of the 22 cases during or after 1994 with complete toxicology reports, 10 (45%) had a blood alcohol concentration (BAC) of greater than 0.05% (g/100 mL) with an illicit substance detected in 4 (18%) cases: (MDMA (3,4-methylenedioxymethamphetamine), methylamphetamine and THC (delta-9-tetrahydrocannabinol) acid). The presence of various therapeutic drugs was also detected in 10 cases (45%) including temazepam, fluoxetine, diazepam, olanzapine, amitriptyline, carbamazepine, codeine, citalopram and valproate. Although the numbers of cases were not high, the urban portion of the River Torrens had a much higher number of drowning events per kilometre compared to other inland waterways in South Australia such as the Murray River. This is most likely due to the vulnerability that exists for intoxicated individuals in the city from falls into the water and to the availability of the river as a means of suicide to members of the adjacent urban population.

Annie, Annie! Are You Okay?: Faces Behind the Resusci Anne Cardiopulmonary Resuscitation Simulator

We investigated the history of Resusci Anne, the well-known cardiopulmonary resuscitation (CPR) simulation trainer. The creation of Resusci Anne began with Peter J. Safar, an accomplished anesthesiologist who experimented with resuscitation of respiration and cardiac function. He collaborated with Asmund S. Laerdal, whose early experimentation with soft plastics allowed him to create a human simulator that could be used to teach the skills of resuscitation to both medical care practitioners and individuals of all walks of life. A special face was chosen for the simulation mannequin, one based on a mysterious death mask of a beautiful woman from the late 19th century. The success of Resusci Anne led to the widespread acceptance of CPR and simulation use in medical training.

Diatomological mapping of water bodies in Chongqing section of the Yangtze River and Jialing River

The diagnosis of drowning is one of the most difficult in forensic medicine. Forensic diatomology has been proposed to be useful in solving the diagnosis of drowning and considered to be a reliable indicator of the site of drowning. The Yangtze River and Jialing River are the main rivers in the Chongqing area (China), and a large number of corpses are found in the rivers every year. However, the distribution of diatoms in the rivers was not fully studied. In the presented study, a Microwave Digestion-Vacuum Filtration-Scanning Electron Microscopy (MD-VF-SEM) method was performed to acquire the qualitative and quantitative data of diatoms of water samples collected from 10 different sites of the Yangtze River and Jialing River in Chongqing section during different seasons. Our study not only created the diatomological maps of water bodies in Chongqing section of the Yangtze River and Jialing River for the first time but also identified some seasonal and site-specific diatoms that can be taken as markers of particular sites or seasons of drowning. The results of our study may provide forensic scientists helpful reference in solving the drowning cases.

Immunohistochemical renal expression of aquaporin 2, arginine-vasopressin, vasopressin receptor 2, and renin in saltwater drowning and freshwater drowning

The diagnosis of drowning is considered one of the most difficult in forensic medicine. Due to the paucity of signs, it is a classical diagnosis by exclusion. For this reason, specific immunohistochemical markers would be useful. Far too little has been done to analyze in-depth the differences between SWD and FWD. We focused on the renal immunohistochemical expression of aquaporin 2, AVP, V2R, and renin in cases of drowning. This study has two purposes: (1) to better understand the differences between saltwater drowning (SWD) and freshwater drowning (FWD), which may indicate different pathophysiology and (2) to eventually identify markers useful for the diagnosis of drowning. We retrospectively investigated 10 cases of SWD gathered from the Institute of Legal Medicine in Genoa (Italy), and 10 cases of FWD from the University Center of Legal Medicine in Geneva (Switzerland). As a control group, we investigated 10 cases of death by gunshot to the head. A strong expression of AQP2 and AVP was significantly (p < 0.05) more evident in cases of SWD than in FWD and control cases. Regarding the V2R, no statistically significant differences were found between the studied groups. The renin tubular expression was particularly intense (p < 0.05) both in SWD and in FWD compared controls. According to our results, AQP2 and AVP represent potential useful markers for the differential diagnosis between SWD and other causes of death, including FWD. Renin may be a useful marker in the diagnosis of drowning but it does not allow for differentiation between FWD and SWD.

Back hemorrhage in bath-related deaths: Insights into the mechanism of bath-related deaths

Forensic pathologists often encounter difficulties while diagnosing bath-related deaths owing to a lack of specific findings for determining the cause. This study reports the characteristic findings noted during autopsy associated with bath-related deaths. The subjects included individuals found deceased in water-filled bathtubs. Originally, a "bathtub death" was defined as a case of drowning in a bathtub without a known cause despite complete investigation including a complete autopsy and examination of the death scene. We also excluded cases with ethanol and/or high drug concentrations in the blood from "bathtub death" cases. Muscular hemorrhages around the scapula were the most common in cases of accidental drowning (72.7%). The frequency of muscular hemorrhages around the scapula was low in cases involving bathtub deaths (11.1%) and natural disease. Subcutaneous hemorrhages in the back were the most frequent in cases of bathtub death (88.9%), followed by accidental drowning (81.8%). The frequency of subcutaneous hemorrhages in the back was low in cases involving suicide and natural disease. The presence of subcutaneous hemorrhages in the back without muscular hemorrhages around the scapula were strongly associated with bathtub deaths (Fisher's exact test, P < 0.0001; sensitivity, 0.84; specificity, 0.91). Subcutaneous hemorrhages were the most frequent in the waist (68.8%), followed by the upper back (50%). Subcutaneous hemorrhages in the back without muscular hemorrhages around the scapula indicated that the deceased had hit their back on falling from a standing position after experiencing disturbances of consciousness. We found the occurrence of orthostatic hypotension while getting out of the bathtub to be the most likely cause for these autopsy findings. Subcutaneous hemorrhages in the back without muscular hemorrhages around the scapula is a characteristic finding of "bathtub deaths". Although this was a preliminary study, the presence of this finding may aid in clarifying the mechanism of bath-related deaths.