Validation and optimization of the diatom L/D ratio as a diagnostic marker for drowning.

If a dead body is discovered in water, it nearly always raises the question about the cause of death, often associated with the persistent problem to differentiate between a drowning incident and post-mortem immersion. In numerous cases, a reliable confirmation of death by drowning is often only possible by a combination of diagnoses obtained from autopsy and additional investigations. As to the latter, the use of diatoms has been suggested (and debated) since decades. Based on the consideration that diatoms are present in almost every natural waterbody and are unavoidably incorporated when water is inhaled, their presence in the lung and other tissues can provide evidence of drowning. However, the traditional diatom test methods are still subject of controversial discussion and suspected of erroneous outcome, predominantly through contamination. A promising alternative to minimize the risk of erroneous outcome seems to be disclosed by the recently suggested MD-VF-Auto SEM technique. Especially the establishment of a new diagnostic marker (L/D ratio), which represents the factorial proportion between the diatom concentration in lung tissue and the drowning medium, allows for clearer distinction of drowning and post-mortal immersion and is largely robust to contamination. However, this highly elaborated technique requires specific devices which are frequently unavailable. We therefore developed a modified method of SEM-based diatom testing to enable the use on more routinely available equipment. Process steps such as digestion, filtration, and image acquisition were thoroughly broken down, optimized, and ultimately validated in five confirmed drowning cases. Taking certain limitations into consideration, L/D ratio analysis provided promising results, even in cases of advanced decomposition. We conclude that our modified protocol indeed opens a way for a broader use of the method in forensic drowning investigation.

Fatal course of undetected Ewing-like sarcoma in a 9-year-old boy with uncharacteristic clinical presentation.

A 9-year-old boy collapsed shortly after complaining of shortness of breath. Despite immediate resuscitation measures, the boy died. A few weeks earlier, he had received antibiotic treatment for respiratory infection. However, the post-mortem examination revealed an advanced tumor mass of the mediastinum with infiltration of vital structures, which was identified as a small blue round neoplasm with aspects of an extramedullary Ewing-like sarcoma by supplementary histological and immunohistochemical examinations.This dramatic clinical course of events shows that the possible presence of serious diseases should always be considered behind harmless symptoms, even in children.

Suitability of specific soft tissue swabs for the forensic identification of highly decomposed bodies.

When decomposition of a recovered body is fairly advanced, identification based on common morphologic features is often impossible. In these cases, short tandem repeat (STR) marker genotyping has established itself as a convenient and reliable alternative. However, at very progressed stages of decomposition, postmortem tissue putrefaction processes can decrease DNA yields considerably. Hence, not all types of tissue are equally suitable for successful STR marker-based postmortem identification. Bone or dental material is often analysed in corpses with advanced decompositional changes. However, processing of these materials is very elaborate and time and resource consuming. We have therefore focused on the suitableness of various types of soft tissue swabs, where DNA extraction is easier and faster. By sampling 28 bodies at various stages of decomposition, we evaluated the suitability of different tissues for genotyping at varying degrees of physical decay. This was achieved by a systematic classification of the sampled bodies by morphological scoring and subsequent analysis of multiple tissue swabs of the aortic wall, urinary bladder wall, brain, liver, oral mucosa and skeletal muscle. In summary, we found variable degrees of suitability of different types of soft tissue swabs for DNA-based identification. Swabs of the aortic wall, the urinary bladder wall and brain tissue yielded the best results - in descending order - even at advanced levels of decay.

Study of backspatter using high-speed video of experimental gunshots.

Backspatter is biological material that is ejected from the entry wound against the line of fire. This phenomenon was also observed in wound ballistic simulations using so called "reference cubes" (12 cm edge length, 10% gelatin, 4 °C, paint pad beneath the cover). High-speed video records from 102 experimental shots to these target models using full metal jacketed bullets in the calibers .32 auto, .38 special, 9 mm Luger and .357 Magnum were analyzed for chronology, morphological appearance and velocity of fluid ejection. Generally, a short tail splashing of surface material occurred when the bullet was penetrating the target. In 51 shots from distance (≥ 5 cm), regardless of caliber and shot range, a linear jet of fluid started in connection with the first collapse of the temporary cavity. The initial velocity of the jet was measured between 6 and 45 m/s. The jet was streaming on for about 60 to 100 ms with a stochastic deviation of ± 13° to the horizontal. Close range and contact shots showed earlier and faster (up to 330 m/s) backspatter depending on the cartridge and the gap between muzzle and target. Gaseous aerosol-like spray and cone-like spatter indicated an increasing influence of muzzle gases with decreasing shot range. Even under standardized experimental conditions, variations of backspatter were observed in near/contact shots.

Correction to: Intra- and intermuscular variations of postmortem protein degradation for PMI estimation.

The above article was published online with an error in the article title.

Intra- and intermuscular variations of postmortem protein degradation for PMI estimation.

In recent years, protein decomposition has become of increasing interest for the use in forensic estimation of the postmortem interval (PMI). Especially skeletal muscle tissue has proven to be a prime target tissue, among other reasons, due to its large abundance in the human body. In this regard, it is important to know whether there are any intra- and intermuscular differences in the behavior of protein degradation. Thus, samples from different locations within several skeletal muscles as well as from cardiac and smooth muscle tissue samples were collected from three autopsy cases with varying degree of decomposition. Samples were analyzed by SDS-PAGE and Western blotting and compared for protein degradation patterns. Intramuscular variations turned out to be minimal and without major influence for the use of the method. Observed intermuscular differences provide possibilities for future improvement of the precision and temporal application range. The results of this study show the strengths and current limitations of protein degradation-based PMI estimation and provide a deeper understanding of intraindividual postmortem protein degradation processes.

Layering of stomach contents in drowning cases in post-mortem computed tomography compared to forensic autopsy.

BACKGROUND: In forensic autopsy, the analysis of stomach contents is important when investigating drowning cases. Three-layering of stomach contents may be interpreted as a diagnostic hint to drowning due to swallowing of larger amounts of water or other drowning media. The authors experienced frequent discrepancies of numbers of stomach content layering in drowning cases between post-mortem computed tomography (PMCT) and autopsy in forensic casework. Therefore, the goal of this study was to compare layering of stomach contents in drowning cases between PMCT and forensic autopsy. METHODS: Drowning cases (n = 55; 40 male, 15 female, mean age 45.3 years; mean amount of stomach content 223 ml) that received PMCT prior to forensic autopsy were retrospectively analyzed by a forensic pathologist and a radiologist. Number of layers of stomach content in PMCT were compared to number of layers at forensic autopsy. RESULTS: In 28 of the 55 evaluated drowning cases, a discrepancy between layering of stomach contents at autopsy compared to PMCT was observed: 1 layer at autopsy (n = 28): 50% discrepancy to PMCT, 2 layers (n = 20): 45% discrepancy, and 3 layers (n = 7): 71.4% discrepancy. Sensitivity of correctly determining layering (as observed at forensic autopsy) in PMCT was 52% (positive predictive value 44.8%). Specificity was 46.6% (negative predictive value 53.8%). In a control group (n = 35) of non-drowning cases, three-layering of stomach contents was not observed. CONCLUSION: Discrepancies of observed numbers of stomach content layers between PMCT and forensic autopsy are a frequent finding possibly due to stomach content sampling technique at autopsy and movement of the corpse prior to PMCT and autopsy. Three-layering in PMCT, if indeed present, may be interpreted as a hint to drowning.

Radiologic identification of disaster victims: a simple and reliable method using CT of the paranasal sinuses.

OBJECTIVE: To assess the reliability of radiologic identification using visual comparison of ante and post mortem paranasal sinus computed tomography (CT). SUBJECTS AND METHODS: The study was approved by the responsible justice department and university ethics committee. Four blinded readers with varying radiological experience separately compared 100 post mortem to 25 ante mortem head CTs with the goal to identify as many matching pairs as possible (out of 23 possible matches). Sensitivity, specificity, positive and negative predictive values were calculated for all readers. The chi-square test was applied to establish if there was significant difference in sensitivity between radiologists and non-radiologists. RESULTS: For all readers, sensitivity was 83.7%, specificity was 100.0%, negative predictive value (NPV) was 95.4%, positive predictive value (PPV) was 100.0%, and accuracy was 96.3%. For radiologists, sensitivity was 97.8%, NPV was 99.4%, and accuracy was 99.5%. For non-radiologists, average sensitivity was 69.6%, negative predictive value (NPV) was 91.7%, and accuracy was 93.0%. Radiologists achieved a significantly higher sensitivity (p < 0.01) than non-radiologists. CONCLUSIONS: Visual comparison of ante mortem and post mortem CT of the head is a robust and reliable method for identifying unknown decedents, particularly in regard to positive matches. The sensitivity and NPV of the method depend on the reader's experience.

A picture is worth a thousand words--the utility of 3D visualization illustrated by a case of survived pancreatic transection.

It is one of the most important tasks of the forensic pathologist to explain the forensically relevant medical findings to medical non-professionals. However, it is often difficult to comment on the nature and potential consequences of organ injuries in a comprehensive way to individuals with limited knowledge of anatomy and physiology. This rare case of survived pancreatic transaction after kicks to the abdomen illustrates how the application of dedicated software programs for three-dimensional reconstruction can overcome these difficulties, allowing for clear and concise visualization of complex findings.

Suicidal knife wound to the heart: challenges in reconstructing wound channels with post mortem CT and CT-angiography.

We present a case of an individual who stabbed himself through the heart with a large knife. Post mortem computed tomography (CT) and CT-angiography were used to assess the stab channel and to reconstruct the sequence of events. After penetrating injuries to the chest, both the intra-thoracic organs and the injury causing instrument may shift (e.g. from pnemothorax) and render forensic reconstructions more challenging. This case report illustrates the potentials and the pitfalls of CT for the reconstruction of penetrating injures to the chest.