Dog Cadavers Research Articles

Ultrasonographic and anatomic study of the canine elbow joint.

To (1) assess the canine elbow joint using a high frequency transducer (18 MHz); (2) describe the echogenicity and echo texture of the joint; and (3) correlate the ultrasonographic images with transparent plastinated anatomic sections. Descriptive study. German Shepherd cross-breed dogs (cadavers, n = 10; live dogs, n = 5). Elbow joints of 10 adult German Shepherd cross-breed dog cadavers were examined by ultrasonography and then 5 cadavers were selected for use in an anatomic study, in which 2 mm thick sections were obtained in the same planes as in the ultrasonographic protocol. Sections were plastinated using the E-12 plastination method and correlated to the corresponding ultrasonographic images. The elbow joints of 5 German Shepherd adult dogs were assessed by ultrasonography for comparison with cadaver images. Good correspondence of soft tissue and bone structures was obtained between ultrasound images and anatomic sections. There was no difference in the ultrasonographic appearance of elbows of cadavers and live dogs in which the muscular, ligamentous, and bone components of the joints were evaluated. This study presents a descriptive comparison of anatomic and ultrasonographic images, which will offer clinicians a more comprehensive understanding of the anatomic structures of the canine elbow joint and serve as reference for further imaging diagnostic studies because of the precise correspondence between anatomic plastinated sections and ultrasonographic images.

Optimized canine dental computed tomographic protocol in medium-sized mesaticepahlic dogs.

The purpose of this study was to develop an optimized imaging protocol for canine dental imaging using single-detector row CT and multidetector row CT. Two medium-sized mesaticephalic cadaver dog heads were scanned using varying slice thickness, sequential vs. helical scanning mode, sequential CT table increment, pitch, image reconstruction algorithm, and an additional moderate edge enhancement filter. For each series, two reviewers scored dental roots as not visible (score: 0), partially visible (score: 1) or completely visible (score: 2). Sharpness of the dento-alveolar margin was scored as blurry (score: 0), sharp (score: 1) or very sharp (score: 2). Consensus reader scores were compared among CT protocols. For single-detector row CT, complete visualization of all tooth roots was only achieved with 1 mm slice thickness and image interval sequential or helical series (pitch of 1 or 2) using a high-frequency image reconstruction algorithm with or without additional edge enhancement. For four-detector row CT, complete visibility of all tooth roots was recorded in all series. For single-detector row CT, all medium frequency algorithm series yielded blurry margin scores and all other series yielded sharp margin scores. For four-detector row CT, sequential and helical 0.5 mm thickness images yielded very sharp dento-alveolar margin scores, whereas the 1 mm series yielded only sharp margin scores. Authors concluded that the optimal dental imaging protocol was a sequential mode 1 mm slice thickness and interval with a high-frequency image reconstruction algorithm and an additional moderate edge enhancement filter.

Lacustrine flow (divers, side scan sonar, hydrogeology, water penetrating radar) used to understand the location of a drowned person

An unusual application of hydrological understanding to a police search is described. The lacustrine search for a missing person provided reports of bottom-water currents in the lake and contradictory indications from cadaver dogs. A hydrological model of the area was developed using pre-existing information from side scan sonar, a desktop hydrogeological study and deployment of water penetrating radar (WPR). These provided a hydrological theory for the initial search involving subaqueous groundwater flow, focused on an area of bedrock surrounded by sediment, on the lake floor. The work shows the value a hydrological explanation has to a police search operation (equally to search and rescue). With hindsight, the desktop study should have preceded the search, allowing better understanding of water conditions. The ultimate reason for lacustrine flow in this location is still not proven, but the hydrological model explained the problems encountered in the initial search.

Scavenging in Northwestern Europe: A Survey of UK Police Specialist Search Officers

Physical search methods used by police specialist searchers are based on counter-terrorism methods and not on the search and recovery of outdoor surface deposited human remains, nevertheless these methods are applied to scenes involving human remains. Additionally, there is limited published forensic literature within Northwestern Europe on the potential taphonomic agents within this region that are capable of modifying human remains through scavenging, scattering and removal. The counter-terrorism basis in physical search methods and the gap in published forensic literature regarding scavenging in this region can potentially impede searchers’ abilities to adapt physical search methods to their full efficiency in the search and recovery of scavenged human remains. This paper analysed through a questionnaire survey of 111 police specialist searchers, within the U.K., the impact of animal scavenging on the search and recovery of human remains.According to questionnaire respondents’ experiences and knowledge, the occurrence of scavenging at scenes in which respondents took part in a physical search for human remains was common (63.46%,n= 66) and happened most frequently with surface deposits (68.25%,n= 43). Scavenging resulted in the recovery of incomplete sets of remains (59.79%, n= 58) and influenced search perimeters (58.33%, n= 35). Scavenging also affected recovery rates at scene searches (80.43%,n= 74) that included the use of cadaver dogs with police handlers. The impact scavengers within this region have on different crime scene scenarios and search methods is not reflected in current published literature or search standards.

Development and validation of a new TD-GC/MS method and its applicability in the search for human and animal decomposition products

Differentiation between human and animal remains by means of analysis of volatile compounds released during decomposition is impossible since no volatile marker(s) specific for human decomposition has been established today. Hence, the identification of such a marker for human decomposition would represent great progression for the discovery of buried cadavers by analytical techniques. Cadaver dogs can be trained more efficiently, the understanding of forensic entomology can be enhanced, and the development of a portable detection device may be within reach. This study describes the development and validation of a new analytical method that can be applied in the search of such (a) specific marker(s). Sampling of the volatile compounds released by decomposing animal and human remains was performed both in a laboratory environment and outdoors by adsorption on sorbent tubes. Different coatings and several sampling parameters were investigated. Next, the volatile compounds were analyzed and identified by a thermal desorber combined with gas chromatography coupled to mass spectrometry (TD-GC/MS). Different GC columns were tested. Finally, the analytical method was validated using a standard mixture of nine representative compounds.

COMPARISON BETWEEN COMPUTED TOMOGRAPHY, FLUOROSCOPY, AND ULTRASONOGRAPHY FOR GUIDING PERCUTANEOUS INJECTION OF THE CANINE INTERVERTEBRAL DISC

A minimally invasive method for delivering injectable therapeutic agents would be desirable for the treatment of intervertebral disc disease in dogs. The purpose of this study was to compare computed tomography (CT), ultrasonography (US), and fluoroscopy modalities for guiding percutaneous injection into canine intervertebral discs. Intervertebral discs of 14 dog cadavers were injected with a gelified ethanol therapeutic agent. Successful injectate placement and injectate leakage were determined based on necropsy inspection of discs. Injection into the nucleus pulposus was successful in 55 of 78 (71%) of all injected discs. Injections guided using CT and fluoroscopy were significantly more successful than US-guided injections. Odds of successful injection without leakage were greater for CT vs. US (P = 0.0026) but there was no significant difference between CT and fluoroscopy (P = 0.0620). Injection success rates did not differ among vertebral sites or dog cadavers of varying weights. Forty-nine (63%) of injection sites had injectate leakage outside the disc and 10 of these involved structures within the vertebral canal. The highest rate of injection success with the least amount of leakage was achieved with CT guidance. Findings indicated that CT, fluoroscopy, and US are feasible modalities for guiding percutaneous injection of a gelified ethanol therapeutic agent into the canine intervertebral disc, with moderate to high success rates for different regions of the spine. However, a moderately high rate of injectate leakage occurred outside of the disc and this should be taken into consideration for future safety and efficacy studies.

Intra-oral mandibular sagittal osteotomy technique to correct mandibular distocclusion and mesio-occlusion

Skeletal malocclusions may be due to disturbances in the growth of the mandible or maxilla. In most cases, discomfort is the result of tooth-to-tooth malocclusion or tooth-to-soft-tissue contact. Currently, in veterinary medicine, these problems are treated palliatively. In humans, orthognathic surgery is indicated to correct severe skeletal malocclusions, offering aesthetic and functional benefits to the patients. This research evaluated the effects of an intra-oral mandibular sagittal split osteotomy in 20 dog cadavers with skeletal malocclusion. After sagittal osteotomy and mandibular repositioning, the osteotomies were fixed with titanium mini-plates and 1.5 mm diameter screws or 1.5 mm bicortical screws. The statistical analysis revealed a significant occlusion difference in the treated cadavers (Wilcoxon test, p<0.05). In 19/20 cadavers there was correction of the angular osteotomy while the mandibular alveolar vessels and nerve were preserved during osteotomy and fixation in all cadavers. In conclusion, intra-oral mandible sagittal osteotomy allowed correction of malocclusion in cadavers. However, it would be important to prepare a preoperative orthodontic-surgical treatment plan to obtain a satisfactory occlusion during the surgery in clinical patients.

Magnetic Resonance Imaging in Cadaver Dogs With Metallic Vertebral Implants at 3 Tesla

Laboratory investigation, ex vivo. Postoperative complications are common after spinal implantation procedures, and magnetic resonance imaging (MRI) would be the ideal modality to image these patients. Unfortunately, the implants cause artifacts that can render MRI nondiagnostic. The WARP-turbo spin echo (TSE) sequence has been developed to mitigate artifacts caused by metal. The objective of this investigation was to evaluate the performance of the WARP-TSE sequence in canine cadaver specimens after implantation with metallic vertebral implants. Magnetic field strength, implant type, and MRI acquisition technique all play a role in the severity of susceptibility artifacts. The WARP-TSE sequence uses increased bandwidth, view angle tilting, and SEMAC (slice-encoding metal artifact correction) to correct for susceptibility artifact. The WARP-TSE technique has outperformed conventional techniques in patients, after total hip arthroplasty. However, published reports of its application in subjects with vertebral column implants are lacking. Ex vivo anterior stabilization of the atlantoaxial joint was performed on 6 adult small breed (<8 kg) cadaver dogs using stainless steel screws and polymethylmethacrylate. Axial and sagittal T2-weighted and short tau inversion recovery MRI was performed using conventional pulse sequences and WARP-TSE sequences at 3 T. Images were assessed qualitatively and quantitatively. Images made with the WARP-TSE sequence had smaller susceptibility artifacts and superior spinal cord margin depiction. WARP-TSE sequences reduced the length over which susceptibility artifacts caused spinal cord margin depiction interference by 24.9% to 71.5% with scan times of approximately 12 to 16 minutes. The WARP-TSE sequence is a viable option for evaluating the vertebral column after implantation with stainless steel implants. N/A.

Pericardioscopic imaging findings in cadaveric dogs: Comparison of an apical pericardial window and sub‐phrenic pericardectomy

To compare the pericardioscopic cardiovascular anatomy visible between apical pericardial window (PW) and sub-phrenic pericardectomy (SPP). Experimental study. Canine cadavers (n = 5). Thoracoscopy was performed using a transdiaphragmatic subxyphoid and right and left intercostal portals. A 4 cm × 4 cm apical PW was created with endoscopic scissors. The intra-pericardiac structures were then pericardioscopically assessed using a subjective ordinal scale (0: not visible, 1: <50% seen, 2: >50% seen) before SPP. Assessment was repeated after SPP. An apical PW provided limited access to the cardiac structures, with only the right ventricle >50% visible in all cadavers. The right atrium, right auricle, left ventricle, right coronary artery, and interventricular paraconal branch of the left coronary artery were observed but were typically <50% visible after apical PW. The left atrium and auricle, and heart base could not be consistently seen through an apical PW. Sub-phrenic pericardectomy significantly improved observation of all intrapericardiac structures assessed, except for the right atrium and right ventricle. PW centered over the cardiac apex limits evaluation of the pericardial space during pericardioscopy compared to SPP in cadaveric dogs.

Biomechanical evaluation of the stabilizing function of the atlantoaxial ligaments under shear loading: A canine cadaveric study

To evaluate the stabilizing function of atlanto-axial ligaments in dogs. Cadaveric biomechanical study. Beagle dog cadavers (n = 10). The craniocervical region was collected from 10 Beagle cadavers, and the occipito-atlanto-axial region was prepared and freed from the surrounding muscles. Care was taken to preserve integrity of the atlantoaxial ligaments and atlantoaxial joint capsule. The atlanto-occipital joints were blocked with 2 diverging transarticular 1.8 mm positive threaded K-wires. Specimen extremities were embedded in polymethylmethacrylate (PMMA) and mounted on a simulator testing shear load at the atlantoaxial joint. Range of motion (ROM) and neutral zone (NZ) were determined with all ligaments intact, after cutting the apical ligament, both alar ligaments, the transverse ligaments and finally after cutting the dorsal atlantoaxial ligament. ROM increased similarly and stepwise during testing. The most significant increase was observed after transection of the alar ligaments. The alar ligaments seem to be the most important ligamentous structures for stabilization of the atlantoaxial joint under shear load.

Femoral nerve block: a novel psoas compartment lateral pre-iliac approach in dogs

ObjectiveTo describe a new approach to block the femoral nerve and to evaluate the distribution of a dye injected into the psoas compartment using a new femoral nerve block approach; to assess its clinical application, when combined with a sciatic nerve block, for surgical anaesthesia/analgesia of the pelvic limb in dogs. Study designProspective anatomical, research and clinical study. AnimalsTwo dog cadavers; two dogs that had to be euthanized for reasons unrelated to this study, and 15 dogs undergoing pelvic limb orthopaedic surgery. MethodsPhase 1: anatomical dissections were performed to determine a simple method to approach the femoral nerve within the psoas compartment. Phase 2: 0.1 mL kg−1 of a lidocaine-new methylene blue solution was injected bilaterally after successful electrolocation of the femoral nerve in two anaesthetized dogs. Colorant spread was evaluated through femoral nerve dissections after euthanasia. Phase 3: in 15 dogs undergoing pelvic limb orthopaedic surgery under light general anaesthesia with isoflurane, intra-operative analgesic effect (cardiovascular responses) and early post-operative pain score, of the novel femoral nerve block combined with a sciatic nerve block as the sole analgesic protocol, were evaluated. ResultsPhase 1: a needle inserted from the lateral aspect of the lumbar muscles, cranially to the iliac crest and with a 30–45° caudo-medial direction, reaches the femoral nerve in the caudal portion of the psoas compartment. Phase 2: Four femoral nerves were stained >2 cm. Phase 3: this novel lateral pre-iliac approach, combined with the sciatic nerve block, blunted the intra-operative cardiovascular response to surgical stimulation in 13 out of 15 anaesthetized dogs. In addition, rescue analgesia was not required in the early post-operative 2-hour period. Conclusion and clinical relevanceThe lateral pre-iliac femoral nerve block technique may provide adequate intra- and early post-operative pain relief in dogs undergoing pelvic limb surgery.

Evaluation of a novel suture material for closure of intestinal anastomoses in canine cadavers

To compare leakage and maximum intraluminal pressures for a novel suture material with pressures for comparable suture material when used in closure of intestinal anastomoses in canine cadavers. Healthy intestines from cadavers of dogs euthanized for reasons unrelated to the study. 18 anastomoses were performed on intestinal sections within 72 hours after dogs were euthanized and intestinal samples collected. Anastomoses were performed with a simple continuous suture pattern. Leakage and maximum intraluminal pressures were measured and recorded for 6 control segments and 18 anastomosed sections. A barbed glycomer 631 suture (size 4-0 United States Pharmacopeia [USP]) was compared with glycomer 631 sutures (sizes 3-0 and 4-0 USP). Results for leakage and maximum intraluminal pressures were compared via an ANOVA. The barbed glycomer 631 suture material leaked at a significantly higher pressure than did the comparable glycomer 631 suture materials. Maximum intraluminal pressures were not significantly different among the suture materials. Barbed glycomer 631 4-0 USP suture material was as effective as glycomer 631 suture materials and may be a safe alternative for use in closure of enterectomies in dogs.

Ultrasound-guided ‘two-in-one’ femoral and obturator nerve block in the dog: an anatomical study

ObjectiveTo evaluate the dye extent and distribution at the lumbar plexus (LP) of three volumes of local anaesthetic-methylene-blue solution administered close to the femoral nerve (FN) by the use of a ventral ultrasound (US)-guided suprainguinal approach (SIA). Study designProspective experimental trial. AnimalsTwenty mongrel canine cadavers weighing 17.7 ± 3.8 kg (mean ± SD). MethodsThe left and right LP of two cadavers were dissected to identify the FN, obturator nerve (ON) and lateral femoral cutaneous nerve (LFCN). The extent and distribution of dye at the LP of each of three volumes of injectate of 0.2, 0.4 and 0.6 mL kg−1 administered close to the FN by a ventral US-guided SIA then were studied in a further 18 dog cadavers (n = 6 per group). Staining of ≥2 cm along the target nerves was indicative of sufficient spread to produce a nerve block. ResultsThe ventral US-guided SIA allowed the observation of the FN within the iliopsoas muscle (IPM) in a total of 17 cadavers. The assessment of the dye extent and distribution revealed a similar pattern regardless of the injected volume. From the injection site, the spreading of injectate occurred in cranial, lateral and caudal directions. The FN and ON were effectively stained in all the cases. The LFCN was not effectively stained in any case. Conclusions and clinical relevanceA volume of 0.2 mL kg−1 administered close to the FN by a ventral US-guided SIA produced a sufficient distribution of the injectate within the IPM to produce effective staining of the FN and ON. This US-guided technique may be an appropriate alternative to previously reported techniques based on electrolocation to block the FN and ON in the dog.

Investigation into scatter radiation dose levels received by a restrainer in small animal radiography

To measure the intensity and distribution of scatter radiation received by a restrainer in veterinary radiography including the intensity of scatter radiation passing through lead protective devices at pre-defined positions. Anthropomorphic phantoms and a Labrador dog cadaver were used to simulate a restrainer and patient. Scatter dose measurements were recorded at the position of the restraining hands, thyroid, breast and gonads with and without appropriate lead protection. This was repeated for the eight most common projections as identified in an initial retrospective survey. Manual restraint of an animal for a radiographic procedure will result in a scatter radiation dose to the restrainer. The level of radiation dose varies between body regions and between projections. The use of appropriate lead protection resulted in statistically significant dose reductions to all body regions with maximum scatter dose reductions between 93 and 100%. While the doses recorded were small (μGy) in terms of associated risk, they are nonetheless cumulative which can result in a more significant dose. Therefore manual restraint should be avoided and forms of immobilisation should be used such as mechanical means, sedation or general anaesthesia. However, if completely necessary both principles of distance and adequate lead protection should be employed.

Normograde and Retrograde Pinning of the Distal Fragment in Humeral Fractures of the Dog

To determine if normograde and retrograde pinning of the distal humeral fragment, to maximize pin purchase in this fragment, would damage vital structures in and around the elbow and shoulder joints in dogs. Anatomic study. Cadaveric dogs (n = 12; 12 thoracic limb pairs). Twelve thoracic limb pairs were harvested from cross-breed dogs and 1 thoracic limb from each pair was allocated to 1 of 3 groups. A transverse osteotomy was created at the junction of the middle and distal thirds in the diaphyseal fracture group (n = 8) and proximal to the supracondylar foramen in the metaphyseal fracture group (n = 8). The humeri in the normograde group (n = 8) were left intact. In all specimens in the distal and supracondylar fracture groups, retrograde pinning of the distal fragment was performed with the elbow flexed. The pins were driven into the medial epicondyle until they exited the skin caudal to the elbow. Dissection of the soft tissues around the exit tract of the pin was performed. The fracture was then reduced and the pin was advanced until it exited the proximal humeral fragment. In the specimens in the normograde group, pinning was initiated on the distal aspect of the medial epicondyle. The pin was directed parallel to the caudal aspect of the medial epicondyle and driven proximally into the humerus until it exited the proximal humerus. Pins exiting the distal aspect of the medial epicondyle passed through muscle origins in 7 specimens in the diaphyseal osteotomy group and in all 8 specimens in the metaphyseal group. The ulnar nerve was entrapped in 1 specimen in the metaphyseal osteotomy group; however, it was not entrapped in any of the specimens in the diaphyseal osteotomy group. The articular cartilage of the trochlea was damaged in 2 specimens in each of the retrograde pinned groups. There was no damage to articular or periarticular structures by pins exiting the proximal humerus. Retrograde pinning of the distal fragment in humeral fractures in the dog may damage the articular cartilage and cannot be recommended.

Cannabinoid receptor type 1 and 2 expression in the skin of healthy dogs and dogs with atopic dermatitis

To determine the distribution of cannabinoid receptor type 1 (CB1) and cannabinoid receptor type 2 (CB2) in skin (including hair follicles and sweat and sebaceous glands) of clinically normal dogs and dogs with atopic dermatitis (AD) and to compare results with those for positive control samples for CB1 (hippocampus) and CB2 (lymph nodes). Skin samples from 5 healthy dogs and 5 dogs with AD and popliteal lymph node and hippocampus samples from 5 cadavers of dogs. CB1 and CB2 were immunohistochemically localized in formalin-fixed, paraffin-embedded sections of tissue samples. In skin samples of healthy dogs, CB1 and CB2 immunoreactivity was detected in various types of cells in the epidermis and in cells in the dermis, including perivascular cells with mast cell morphology, fibroblasts, and endothelial cells. In skin samples of dogs with AD, CB1 and CB2 immunoreactivity was stronger than it was in skin samples of healthy dogs. In positive control tissue samples, CB1 immunoreactivity was detected in all areas of the hippocampus, and CB2 immunoreactivity was detected in B-cell zones of lymphoid follicles. The endocannabinoid system and cannabimimetic compounds protect against effects of allergic inflammatory disorders in various species of mammals. Results of the present study contributed to knowledge of the endocannabinoid system and indicated this system may be a target for treatment of immune-mediated and inflammatory disorders such as allergic skin diseases in dogs.

Anatomical and radiological study of the thoracic paravertebral space in dogs: iohexol distribution pattern and use of the nerve stimulator

ObjectiveTo describe the landmarks and methodology to approach the thoracic paravertebral space in dogs; to evaluate if intercostal muscular response could be evoked by a nerve-stimulator; to radiographically assess the distribution pattern of a radio-opaque contrast medium after thoracic paravertebral injections. Study designRandomized, controlled, experimental trial. AnimalsTwo mongrel dog cadavers (anatomical study) and 24 mongrel dogs (experimental study). MethodsFor the anatomic study 0.2 mL kg−1 of new methylene blue (NMB) was injected at the 5th thoracic paravertebral space; for the experimental study dogs were divided into three groups and received 1 (T5), 2 (T4 and T6) or 4 (T4, T5, T6 and T7) paravertebral injections of iohexol. The paravertebral approach was performed with insulated needles using landmarks and a blind technique. When the needle tip reached the respective thoracic paravertebral space, the nerve-stimulator was switched-on and the presence/absence of intercostal muscular twitch was registered, thus a total volume of 0.2 mL kg−1 of iohexol, divided into equal parts for each injection point, was administered. Radiological studies were performed with two orthogonal projections at different times. Positive injection was confirmed when the paravertebral space was occupied by iohexol in both projections. ResultsNMB was distributed in the T5 paraverterbal space. In the experimental study, when the needle tip reached the respective paravertebral space, intercostal twitching was obtained in 80% of the total injections with a stimulating current of 0.5 mA. The incidence of positive cases when the intercostal twitch was obtained with 0.5 mA was 83.3%. The main distribution pattern observed was cloud like without longitudinal diffusion. Conclusion and clinical relevanceIntercostal muscular responses obtained with a stimulating current of 0.5 mA could be useful to locate thoracic spinal nerves in dogs and in our study the injected solution was confined to one thoracic paravertebral space.

MAGNETIC RESONANCE IMAGING OF THE LIGAMENTOUS STRUCTURES OF THE OCCIPITOATLANTOAXIAL REGION IN THE DOG

Our objectives were to establish a magnetic resonance (MR) protocol for the examination of, and then describe, the normal ligaments and the supporting structures of the occipitoatlantoaxial region. This was done in 10 cadaver dogs. In addition, MR images of three patients with cervical pain localized to the occipitoatlantoaxial region are included to provide examples of ligamentous abnormalities. All ligaments were hypointense in all pulse sequences. The apical, dorsal atlantoaxial, and dorsal longitudinal vertebral ligaments were seen best in the sagittal T1W and PD-weighted images. The transverse ligament was best visualized in the transverse plane in all pulse sequences and appeared to be confluent with the dorsal longitudinal vertebral ligament dorsal to the dens in the sagittal plane. A 20° dorsal plane reconstructed image in 0.6-mm slice thickness was necessary to visualize the alar ligaments, which were visible in 9/10 dogs. The dorsal longitudinal vertebral ligament appeared continuous with the apical ligament and tectorial membrane. Abnormalities in clinically affected dogs included thickening of the alar ligaments, absence of transverse ligament and elongation, and irregularity of the apical ligament.

Odor mortis

This study, the third of a series on the odor signature of human decomposition, reports on the intermittent nature of chemical evolution from decomposing human remains, and focuses primarily on headspace analysis from soil associated with older human remains (10–60+ years) from different environments around the globe. Fifty grams of soil were collected in 40mL glass vials with polypropylene sealed lids from soil above known or suspected graves and from subsurface chemical plumes associated with human decompositional events. One hundred eighty six separate samples were analyzed using gas chromatography–mass spectrometry (GC–MS). After comparison to relevant soil controls, approximately fifty volatile chemical compounds were identified as being associated with human remains. This manuscript reports these findings and identifies when and where they are most likely to be detected showing an overall decrease in cyclic and halogenated compounds and an increase in aldehydes and alkanes as time progresses. This research identifies the “odor signatures” unique to the decomposition of human remains with projected ramifications on cadaver dog training procedures and in the development of field portable analytical instruments which can be used to locate human remains in shallow burial sites.

Analysis of synthetic canine training aids by comprehensive two-dimensional gas chromatography–time of flight mass spectrometry

Cadaver dogs are trained on a variety of materials, including artificial or pseudo scents. The chemical components of commercially available pseudo scents are not known, so their accuracy as a decomposition odour mimic and their effectiveness as a canine training aid have not been evaluated. Two pseudo scents that are commercially available and used for training cadaver dogs were analysed using comprehensive two-dimensional gas chromatography–time of flight mass spectrometry (GC×GC–TOFMS). The two formulations were determined to be simplistic in their composition, compared to real cadaveric volatile organic compound (VOC) mixtures, with only a few major components. The enhanced GC×GC–TOFMS peak capacity was nevertheless useful to discriminate less intense peaks from large overloaded peaks. The availability of both dimension retention times combined with the peak finding and deconvolution algorithm, enabled the chemical characterization of the two formulations. Additionally, high resolution (HR) TOFMS was used to extract molecular formulae and confirm identities of analytes. The seven compounds identified by this work have not been reported previously as volatile products of decomposition, indicating that these pseudo scents are not to be considered as an accurate representation of cadaveric decomposition odour. Further research on the olfaction of scent detection canines and the chemical composition of their target odourants needs to be conducted to develop improved canine training aids.