Gunshot residue on dark materials: a comparison between infrared photography and the use of an alternative light source.

The pattern of gunshot residue (GSR) includes important information about muzzle-target distance since a larger GSR distribution diameter indicates a larger shooting distance. GSR may not be visible to the naked eye when, for example, it is located on dark textiles. In such cases, further procedures need to be performed in order to visualize the pattern of GSR. Besides chemical procedures, an alternative light source or infrared photography can be utilized for non-destructive GSR visualization. In the work presented, these two techniques are compared based on shooting experiments using 26 different dark textiles. Within the range of the alternative light source, the use of a 440-nm light in combination with an orange-colored filter led to the best visualization of GSR in the form of fluorescent particles. Infrared photography, on the other hand, visualized GSR as dark particles, whereas-ideally-the dark textile reflected the infrared light and appeared bright. The comparison of both techniques revealed that the GSR distribution visualized by infrared photography was not identical to the GSR distribution visualized with 440-nm illumination in combination with an orange-colored filter. We concluded that infrared photography visualizes the inner powder soot zone, whereas illumination at 440 nm leads to fluorescence of the outer powder soot zone, which can be visualized using an orange-colored filter. Knowledge of this difference in visualization of the two powder soot zones is important for forensic practitioners assessing firing distances. In the literature, however, this difference is not noted as clearly.

Fracture energy threshold in parry injuries due to sharp and blunt force.

Blows with axes, machetes or blunt objects such as baseball bats, truncheons, etc. are often parried, resulting in typical parry injuries, or so-called nightstick fractures to the ulna. In this study, we sought to assess the impact energy required to break the ulna in such parry incidents in an experimental setting using semisynthetic and fully synthetic models. Twenty-seven sheep radii and 33 polyurethane synthetic bones were cast into gelatin prior to being fired at with missiles made of a section of an axe blade or steel rod at different firing velocities using a compressed-nitrogen cannon. Each model was then examined as to the presence of hair-line fractures or complete fractures. Sheep bones and synthetic bones displayed comparable results when struck by the axe missile; here, a clear fracture threshold was evident between 14.00 and 15.26 J. When struck by the rod missile, only the synthetic bones produced significant results, namely a fracture threshold between 20.15 and 23.59 J. In conclusion, our results show an ulnar fracture threshold of approximately 15 J when struck by an axe. The experiments regarding blows with a rod displayed a fracture threshold of around 22 J, but, as this could not be validated with biological bones, this result is questionable.

Annular distribution patterns of .357 Magnum fragments in soft tissue simulants after striking hard material that prevented the bullet from exiting.

The distribution of bullet fragments inside the body can provide information for the reconstruction of events in shooting incidents. The formation of an annular distribution pattern of bullet fragments was recently presented in a case report. The fragments were scattered radially around an exit-re-entrance wound resulting from collision of the bullet with a floor tile immediately after perforating the body. Such an annular distribution pattern of bullet fragments around an exit-re-entrance wound would indicate that a body was in close contact with hard material, for instance, lying on hard ground or leaning against a concrete wall, when the shot was fired. The aim of this experimental study was to investigate the formation and reproducibility of the annular distribution pattern of bullet fragments. It was assumed that the distribution pattern would be formed when hard material blocks a bullet from exiting a soft tissue simulant. Furthermore, the dependency of this distribution pattern on the impact angle was assessed. For this purpose, .357 Magnum bullets were fired at ballistic soap blocks with a steel plate at the rear end of the soap block. Six shots were performed at an impact angle of 90° (experiment 1), and six shots were performed at an impact angle of 45° (experiment 2). The distribution pattern of the fragments inside the individual soap blocks was examined via computed tomography (CT). In experiment 1, the bullets burst, and large fragments formed annular distribution patterns with a radial extent of approximately 4.9 cm and a maximum depth of approximately 2.3 cm. In experiment 2, the bullets ricocheted from the steel plate, and tiny fragments formed small annular distribution patterns at the points of ricochet with a radial extent of approximately 1.5 cm and a maximum depth of approximately 1.2 cm. The end position of the large main fragments was approximately 9.7 cm distant from the point of ricochet at a mean depth of 2.7 cm. The mean kinetic energy of the bullets at the time of impact was 580 J in experiment 1 and 394 J in experiment 2. Distribution patterns of bullet fragments in the body may provide information not only on the impact angle of a bullet but also on whether the body was in contact with a hard material that blocked the bullet from exiting the body. CT proved to be an appropriate imaging method for such investigations.

Crucial role of tumor necrosis factor receptor 1 expression on nonhematopoietic cells for B cell localization within the splenic white pulp.

During immune responses the initial activation of B cells takes place in T cell zones of periarteriolar lymphoid sheaths (PALS) of the splenic white pulp. After initial activation, B cells migrate into the primary follicles and, in association with follicular dendritic cells (FDCs), undergo clonal expansion and differentiation giving rise to germinal centers (GCs). Peanut agglutinin binding (PNA+) cells of the GC differentiate further into memory or plasma cells. Here we report that in tumor necrosis factor receptor 1-deficient mice (TNFR1(-/-)), the location of B cells was altered and that plasma cells were abnormally distributed in the splenic PALS. In contrast to lymphotoxin alpha-deficient mice (LTalpha-/-), bone marrow or fetal liver transplantation did not correct the abnormal organization of the spleen, location of B cells, the lack of an FDC network, nor the antibody response in TNFR1(-/-) mice. These results argue for a crucial role of TNFR1 expression on nonhematopoietic cells for the maintenance of the splenic architecture and proper B cell location. In addition, the lack in development of an FDC network after adoptive transfer suggests that either FDCs are not of bone marrow origin or that they depend on signals from nonhematopoietic cells for maturation.

Virtopsy: fatal stab wounds to the skull--the relevance of ante-mortem and post-mortem radiological data in case reconstructions.

Homicides with a survival of several days are not uncommon in forensic routine work. Reconstructions of these cases by autopsy alone are very difficult and may occasionally lead to unsatisfying results. For the medico-legal reconstruction of these cases, ante-mortem and post-mortem radiological imaging should always be included in the expertise. We report on a case of fatal penetrating stab wounds to the skull in which a case reconstruction was only possible by combining the radiological ante- and post-mortem data with the autopsy findings.

A fully synthetic lung model for wound-ballistic experiments-First results.

PURPOSE: Today, synthetic models have all but replaced animal and corpse models in examining damage to soft-tissues and skeletal structures by ballistic trauma. As, however, non-solid organs such as the lungs, have not been able to be replaced by a fully synthetic model we attempted to create such a model. MATERIAL AND METHODS: 20% ordnance gelatine was frothed with a household mixer and cooled to stable foam. Several of these foam blocks were then stuck together with liquid gelatine and placed between 10% gelatine blocks. As controls, we embedded pig lungs in gelatine and compared the wound channels seen in computed tomography created upon shooting with 9mm Luger. RESULTS: The fully synthetic models displayed radiological and physical densities comparable to real lungs. The wound profile characteristics of the fully synthetic lung models were very similar to the semisynthetic swine-gelatine models regarding the permanent wound cavity. Furthermore, in both semi- and fully synthetic models we detected a ring surrounding the permanent wound channel, most likely representing the remnants of the temporary wound cavity. CONCLUSION: Our results indicate that this fully synthetic lung model is a viable substitute for ballistic experiments on lungs. We believe that further research on the temporary wound channel in lungs is possible with this model in order to provide more insight into the effect of ballistic trauma to the lungs not seen otherwise.

Forensic assessment of survived strangulation.

By a retrospective analysis of all survived strangulation cases examined at the Institute of Forensic Medicine of Berne, Switzerland between 1987 and 2002, the authors tried to find out, if findings and symptoms of victims could be related to the fierceness of the assault and the mode of strangulation and if general evaluation criteria could be established on the basis of objective findings. One hundred and thirty-four survived strangulation cases were analysed on the basis of written reports, photographies and schematical sketches. Findings and symptoms reflected the fierceness of the assault in 71% of all cases by displaying a continuum of findings from minor injuries to severe traumatisation. This applied especially for cases of manual strangulation while other modes of strangulation resulted in different constellations of findings. As a result of this study, the authors deem the following classification of three degrees of severity as practical on condition that a complete forensic medical examination was performed upon the surviving victim shortly after the incident of strangulation: Light strangulation, confined to skin abrasions and/or reddening of the skin of the neck. Moderate strangulation, defined as bruising to, and/or bleeding from the neck, and/or damage to deeper soft tissues or the larynx, as exhibited by the symptoms of sore throat, difficulty in swallowing, and hoarseness. Severe, life-threatening strangulation if the victim presents petechial bleedings as a result of venous congestion with or without accompanying loss of consciousness.

Application of Prionics Western blotting procedure to screen for BSE in cattle regularly slaughtered at Swiss abattoirs.

Disease-specific PrP (PrP(Sc)) is at least part of the infectious particle (prion) causing bovine spongiform encephalopathy (BSE) or scrapie in sheep. Digestion with protease allows a distinction between normal PrP (PrP(C)) and PrP(Sc) i.e. PrP(C) is completely digested while PrP(Sc) is cleaved at the N-terminus leading to a fragment of reduced molecular weight (PrP 27-30). Detection of this fragment by Western blotting has been described more than a decade ago for rodent PrP. We have now optimized the technique in order to allow rapid analysis of hundreds of samples per day. Here we report the application of this technique to the analysis of 3000 regularly slaughtered cattle from Swiss abattoirs. For comparison all the animals were subsequently examined by classical methods (i.e. histology and immunohistochemistry). All but one animal were negative for BSE by all methods. The Western blot positive animal was confirmed to be a BSE case and the carcass was removed from the food chain. We conclude that it is feasible to examine slaughtered cattle on a routine basis without causing delays to the meat processing industry.

"Blind spots" in forensic autopsy: improved detection of retrobulbar hemorrhage and orbital lesions by postmortem computed tomography (PMCT).

OBJECTIVES: The purpose of this study was to correlate the occurrence of retrobulbar hemorrhage (RBH) with mechanism of injury, external signs and autopsy findings to postmortem computed tomography (PMCT). METHODS: Six-teen subjects presented with RBH and underwent PMCT, external inspection and conventional autopsy. External inspection was evaluated for findings of the bulbs, black eye, raccoon eyes and Battle's sign. Fractures of the viscerocranium, orbital lesions and RBH were evaluated by PMCT. Autopsy and PMCT was evaluated for orbital roof and basilar skull fracture. RESULTS: The leading manner of death was accident with central regulatory failure in cases of RBH (31.25%). Imaging showed a high sensitivity in detection of orbital roof and basilar skull fractures (100%), but was less specific compared to autopsy. Volume of RBH (0.1-2.4ml) correlated positively to the presence of Battle's sign (p<0.06) and the postmortem interval. Ecchymosis on external inspection correlated with RBH. There was a statistical significant correlation between bulbar lesion and RBH. Orbital roof fracture count weakly correlated with the total PMCT derived RBH volume. Maxillary hemosinus correlated to maxillary fractures, but not to RBH. CONCLUSIONS: RBH are a specific finding in forensically relevant head trauma. PMCT is an excellent tool in detecting and quantifying morphological trauma findings particularly in the viscerocranium, one of the most relevant "blind spots" of classic autopsy. PMCT was superior in detecting osseous lesions, scrutinizing autopsy as the gold standard.

Radiological stab wound channel depiction with instillation of contrast medium.

The radiological depiction of stab wounds in soft-tissues using multislice computed tomography is difficult and the hereby obtained images often lack contrast. To overcome these shortcomings we tried a new method. We gently instilled the contrast medium Lipiodol((R)) Ultra-fluide into five experimentally induced stab wounds on a pork haunch. Subsequent MSCT reconstructions of the wounds delivered clear, for medical laymen easily appreciable images regarding the stab direction and the stab depth. We believe that this easy and rapid technique can be useful in the examination of stab wounds in living and dead victims of sharp trauma.

Injuries due to sharp trauma detected by post-mortem multislice computed tomography (MSCT): a feasibility study.

Modern cross-sectional imaging techniques are being increasingly implemented in forensic pathology. In order to assess the practicability of such a method, namely post-mortem multislice computed tomography (MSCT) in cases of fatal cut and stab injuries, 12 corpses underwent such an examination prior to forensic autopsy. The questions regarding detection of foreign bodies, wound channels, skeletal and organ injuries, as well as the cause of death were addressed at MSCT and autopsy. The results of the two techniques revealed that post-mortem MSCT a useful tool in the assessment of such injuries.

Incidence of auditory ossicle luxation and petrous bone fractures detected in post-mortem multislice computed tomography (MSCT).

As the auditory ossicles are difficult to display without harming them in conventional autopsies, lesions of these minute bones and the ossicular chain are regularly missed. In this study, the method of choice in clinical medicine for the examination of such lesions, namely multislice computed tomography, was applied to 100 corpses. The hereby obtained results regarding ossicle luxation and petrous bone fracture indicated that the lesions were not dependant on the amount, but rather on the type of energy inflicted to the head.

Post-mortem imaging of laryngohyoid fractures in strangulation incidents: first results.

Fractures and soft-tissue injuries of the neck are of great importance in forensic pathology, as they help in assessing whether strangulation took place, and if so, how severely. In this study, we examined the usefulness of post-mortem imaging with multislice computed tomography (MSCT) in detecting lesions of the laryngohyoid structures and the surrounding soft-tissues. For this purpose, we examined MSCT images of the neck of eight deceased persons who had suffered different types of strangulation and compared the findings with those obtained at the subsequent forensic autopsy. In six of the eight cases (75%), the fracture findings at autopsy were concordant with those found with MSCT. In the two non-congruent cases, MSCT revealed fractures, which were not discovered at autopsy. Soft-tissue haemorrhages were detected by autopsy in five cases, but only in one case with MSCT. MSCT does not suffice in detecting soft-tissue injuries. These preliminary results are promising regarding the detection of fractures in strangulation cases. If these results can be confirmed in larger studies, we believe that post-mortem MSCT may serve - in combination with a thorough external examination and a profound incident-scene investigation - as a useful decision-making tool regarding the necessity of further examinations, i.e. autopsy.

Correlation between skeletal trauma and energy in falls from great height detected by post-mortem multislice computed tomography (MSCT).

Fatal falls from great height are a frequently encountered setting in forensic pathology. They present--by virtue of a calculable energy transmission to the body--an ideal model for the assessment of the effects of blunt trauma to a human body. As multislice computed tomography (MSCT) has proven not only to be invaluable in clinical examinations, but also to be a viable tool in post-mortem imaging, especially in the field of osseous injuries, we performed a MSCT scan on 20 victims of falls from great height. We hereby detected fractures and their distributions were compared with the impact energy. Our study suggests a marked increase of extensive damage to different body regions at about 20 kJ and more. The thorax was most often affected, regardless of the amount of impacting energy and the primary impact site. Cranial fracture frequency displayed a biphasic distribution with regard to the impacting energy; they were more frequent in energies of less than 10, and more than 20 kJ, but rarer in the intermediate energy group, namely that of 10-20 kJ.

Gunshot injuries detected by post-mortem multislice computed tomography (MSCT): a feasibility study.

Modern cross-sectional imaging techniques are being increasingly implemented in forensic pathology. These methods may serve as an adjuvant to classic forensic autopsies or even replace them altogether in the future. In order to assess the practicability of such a method, namely post-mortem multislice computed tomography (MSCT) in fatal gunshot injuries, 22 corpses underwent such an examination prior to forensic autopsy. The cardinal questions of the location of entrance and exit wounds, the detection of bullets and bullet fragments in the body, the bullet course, inflicted injuries and cause of death were addressed at MSCT and autopsy. The results of the two techniques revealed that post-mortem MSCT can answer these questions reliably and is therefore a useful tool in the assessment of such injuries.

Extended CT scale overcomes restoration caused streak artifacts for dental identification in CT--3D color encoded automatic discrimination of dental restorations.

OBJECTIVE: Besides DNA, dental radiographs play a major role in the identification of victims in mass casualties or in corpses with major postmortem alterations. Computed tomography (CT) is increasingly applied in forensic investigations and is used to scan the dentition of deceased persons within minutes. We investigated different restoration materials concerning their radiopacity in CT for dental identification purposes. METHODS: Extracted teeth with different filling materials (composite, amalgam, ceramic, temporary fillings) were CT scanned. Radiopacities of the filling materials were analyzed in extended CT scale images. RESULTS: Radiopacity values ranged from 6000-8500HU (temporary fillings), 4500-17000HU (composite fillings) and >30710HU (Amalgam and Gold). The values were used to define presets for a 3D colored volume rendering software. CONCLUSIONS: The effects of filling material caused streak artifacts could be distinctively reduced for the assessment of the dental status and a postprocessing algorithm was introduced that allows for 3D color encoded visualization and discrimination of different dental restorations based on postmortem CT data.

Antibody studies in a patient with acute thrombocytopenia following infusion of plasma containing anti-PI(A1).

Immune thrombocytopenia due to passive transfer of anti-PI(A1) alloantibody has been noted as a rare but potentially dangerous complication of plasma transfusions. We report a patient with a preoperative platelet count of 241 x 10(9)/l who developed severe thrombocytopenia within 2 hr following transfusion of 2 U of fresh frozen plasma. The plasma donor was found to be a PI(A1)-negative woman. The platelet count of the PI(A1)-positive patient recovered within 7 days to normal values. In the frozen plasma, excessive antibody binding to GPIIb-IIIa on the recipient's platelets was detected. The antibody was shown to have anti-PI(A1)-specificity. Only 40 min after transfusion of the frozen plasma, no antibody was detected in the plasma of the recipient. This case suggests that passively administered anti-PI(A1) alloantibody is immediately adsorbed onto the recipient's platelets and thus removed from circulation.