The initial changes of fat deposits during the decomposition of human and pig remains

The early stages of adipocere formation in both pig and human adipose tissue in aqueous environments have been investigated. The aims were to determine the short-term changes occurring to fat deposits during decomposition and to ascertain the suitability of pigs as models for human decomposition. Subcutaneous adipose tissue from both species after immersion in distilled water for up to six months was compared using Fourier transform infrared spectroscopy, gas chromatography-mass spectrometry and inductively coupled plasma-mass spectrometry. Changes associated with decomposition were observed, but no adipocere was formed during the initial month of decomposition for either tissue type. Early-stage adipocere formation in pig samples during later months was detected. The variable time courses for adipose tissue decomposition were attributed to differences in the distribution of total fatty acids between species. Variations in the amount of sodium, potassium, calcium, and magnesium were also detected between species. The study shows that differences in total fatty acid composition between species need to be considered when interpreting results from experimental decomposition studies using pigs as human body analogs. © 2008 American Academy of Forensic Sciences

Reflections on a 'virtual' practice development unit: changing practice through identity development

Aims. This paper draws together the personal thoughts and critical reflections of key people involved in the establishment of a ‘virtual’ practice development unit of clinical nurse specialists in the south of England. Background. This practice development unit is ‘virtual’ in that it is not constrained by physical or specialty boundaries. It became the first group of Trust-wide clinical nurse specialists to be accredited in the UK as a practice development unit in 2004. Design and methods. The local university was asked to facilitate the accreditation process via 11 two-hour audio-recorded learning sessions. Critical reflections from practice development unit members, leaders and university staff were written 12 months after successful accreditation, and the framework of their content analysed. Findings and discussion. Practice development was seen as a way for the clinical nurse specialists to realize their potential for improving patient care by transforming care practice in a collaborative, interprofessional and evolutionary manner. The practice development unit provided a means for these nurses to analyse their role and function within the Trust. Roberts’ identity development model for nursing serves as a useful theoretical underpinning for the reflections contained in this paper. Conclusions. These narratives provide another example of nurses making the effort to shape and contribute to patient care through organizational redesign. This group of nurses began to realize that the structure of the practice development unit process provided them with the means to analyse their role and function within the organization and, as they reflected on this structure, their behaviour began to change. Relevance to clinical practice. Evidence from these reflections supports the view that practice development unit participants have secured a positive and professional identity and are, therefore, better able to improve the patient experience

Enhanced Characterization of the Smell of Death by Comprehensive Two-Dimensional Gas Chromatography-Time-of-Flight Mass Spectrometry (GCxGC-TOFMS)

Soon after death, the decay process of mammalian soft tissues begins and leads to the release of cadaveric volatile compounds in the surrounding environment. The study of postmortem decomposition products is an emerging field of study in forensic science. However, a better knowledge of the smell of death and its volatile constituents may have many applications in forensic sciences. Domestic pigs are the most widely used human body analogues in forensic experiments, mainly due to ethical restrictions. Indeed, decomposition trials on human corpses are restricted in many countries worldwide. This article reports on the use of comprehensive two-dimensional gas chromatography coupled with time-of-flight mass spectrometry (GCxGC-TOFMS) for thanatochemistry applications. A total of 832 VOCs released by a decaying pig carcass in terrestrial ecosystem, i.e. a forest biotope, were identified by GCxGC-TOFMS. These postmortem compounds belong to many kinds of chemical class, mainly oxygen compounds (alcohols, acids, ketones, aldehydes, esters), sulfur and nitrogen compounds, aromatic compounds such as phenolic molecules and hydrocarbons. The use of GCxGC-TOFMS in study of postmortem volatile compounds instead of conventional GC-MS was successful

Post-mortem volatiles of vertebrate tissue

Volatile emission during vertebrate decay is a complex process that is understood incompletely. It depends on many factors. The main factor is the metabolism of the microbial species present inside and on the vertebrate. In this review, we combine the results from studies on volatile organic compounds (VOCs) detected during this decay process and those on the biochemical formation of VOCs in order to improve our understanding of the decay process. Micro-organisms are the main producers of VOCs, which are by- or end-products of microbial metabolism. Many microbes are already present inside and on a vertebrate, and these can initiate microbial decay. In addition, micro-organisms from the environment colonize the cadaver. The composition of microbial communities is complex, and communities of different species interact with each other in succession. In comparison to the complexity of the decay process, the resulting volatile pattern does show some consistency. Therefore, the possibility of an existence of a time-dependent core volatile pattern, which could be used for applications in areas such as forensics or food science, is discussed. Possible microbial interactions that might alter the process of decay are highlighted

Interneuron- and GABAA receptor-specific inhibitory synaptic plasticity in cerebellar purkinje cells

Inhibitory synaptic plasticity is important for shaping both neuronal excitability and network activity. Here we investigate the input and GABA(A) receptor subunit specificity of inhibitory synaptic plasticity by studying cerebellar interneuron-Purkinje cell (PC) synapses. Depolarizing PCs initiated a long-lasting increase in GABA-mediated synaptic currents. By stimulating individual interneurons, this plasticity was observed at somatodendritic basket cell synapses, but not at distal dendritic stellate cell synapses. Basket cell synapses predominantly express β2-subunit-containing GABA(A) receptors; deletion of the β2-subunit ablates this plasticity, demonstrating its reliance on GABA(A) receptor subunit composition. The increase in synaptic currents is dependent upon an increase in newly synthesized cell surface synaptic GABA(A) receptors and is abolished by preventing CaMKII phosphorylation of GABA(A) receptors. Our results reveal a novel GABA(A) receptor subunit- and input-specific form of inhibitory synaptic plasticity that regulates the temporal firing pattern of the principal output cells of the cerebellum

The formation of adipocere in aquatic environments

University of Technology, Sydney. Faculty of Science.NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. The hardcopy may be available for consultation at the UTS Library.NO FULL TEXT AVAILABLE. This thesis contains 3rd party copyright material. ----- The term adipocere refers to a waxy substance that is associated with dead bodies that have been under water, in moist soil or in other moist environments for prolonged periods of time. Adipocere is comprised of a mixture of saturated fatty acids that result from the late post mortem changes associated with the decomposition of adipose tissue in the body. In a forensic context, its presence becomes significant because of its ability to slow decomposition and, in some cases, preserve remains. The particular factors associated with aqueous environments on adipocere formation have been investigated. The aims were to determine the effect of these factors on the rate and extent of adipocere formation and the ability of these factors to characterise the chemical composition of this product. Interest in this decomposition product has been growing rapidly since the discovery of the "Iceman", a well preserved 5300•-year old corpse discovered in an Alpine glacier. Knowledge of adipocere formation is limited although most studies have focussed on its chemical components and microscopic properties. To date, no one has undertaken a systematic characterisation of its formation in both human and non-human tissue submerged in aquatic environments. Furthermore, its potential to be useful in a forensic context highlighted the need for a comprehensive analysis of adipocere formation in aquatic burial environments. In order to investigate this post-mortem product. a rapid and reliable method was created to separate and identify fatty acids present in adipocere. This involved the development and validation of a simplified solid-phase extraction-gas chromatography mass spectrometry method for the quantification of free fatty acids commonly found in adipocere. The method described in this study has comparable limits of quantification to the more sensitive methods previously reported in the literature for adipocere, but has significant advantages in that it has greater recoveries, is consistently reproducible, less complicated and less time consuming. This allows for the rapid and accurate determination of low levels of fatty acids in adipocere samples from an aqueous environment. The formation of model adipocere was used as the basis for experimental work involving the analysis of aquatic burial factors. Whilst human adipose tissue was obtained for this research, it was not possible to attain the quantity required to conduct a large scale systematic investigation. Instead, a comparison study was conducted between pig and human adipose tissue to determine the suitability of pigs to model human adipocere formation. The experiments reported were also designed to illustrate the changes in fat deposits of human and pig adipose tissue during the initial month of decomposition and, thereby, determine the chemical profile of early-stage adipocere formation. This work indicates that although pig adipose tissue is similar to human adipose tissue and therefore suitable to mimic human decomposition, some margins of error exist when comparisons are being made between the species. The formation of model adipocere allowed for the analysis of individual factors present in the burial environment and their effect on the rate of formation and composition of adipocere. The formation of adipocere within the control series, which acted as the benchmark for comparison with the other experiments is described. Those conditions known to favour adipocere formation; the complete submergence in a warm, anaerobic and aquatic environments, adequate skin and adipose tissue and sufficient bacteria were used in this research. The factors investigated included pH and the influence of various cations across the pH range, different types of water and the influence of temperature and body wrappings on adipocere formation. The majority of burial environments successfully formed adipocere at various stages of formation. Comparison with the control series allowed the various burial factors to be linked with either an acceleration or retardation of the decomposition process and, hence, the formation of adipocere. A field study was included in this research to address any differences associated with laboratory and field conditions. A comparison of field samples with experimentally created adipocere using water collected from the field site is described. Both human and pig adipose tissue was included in the study, which also allowed for an investigation of the variations associated with human and pig decomposition and subsequent adipocere formation. The study identified differences between the formation of adipocere from laboratory and field sites and between pig and human adipose tissue. The results emphasise the importance of using field sites and human tissue to simulate adipocere formation. The results of this research confirm previous field observations regarding adipocere formation in aquatic environments and identify new aspects of its formation which were previously unknown. The findings represent an important contribution to the field of forensic science by providing valuable insights into an area of decomposition in which limited research and knowledge exists

The Effect of Body Coverings on the Formation of Adipocere in an Aqueous Environment

Adipocere is a postmortem decomposition product that consists of a mixture of fatty acids. The rate of formation of adipocere from pig adipose tissue in an aqueous environment has been monitored. The effect of various clothing and carpet material types on the process was investigated. The fatty acid composition of the adipocere was determined at regular intervals using gas chromatography-mass spectrometry. Examination of the changes to fatty acid concentrations allowed the degree of adipocere formation in the different environments to be estimated. The study demonstrated that the rate at which adipocere forms is particularly accelerated by the presence of coverings produced from natural materials. Elemental analysis by inductively coupled plasma-mass spectrometry revealed, for the most part, little change to the cations present in the adipocere formed. However, an increase in Ca concentration was observed for tissue wrapped in acrylic carpet, which was associated with a CaCO 3 additive used in the carpet manufacture. © 2011 American Academy of Forensic Sciences

Adipocere formation in a river environment

Adipocere is a late post-mortem decomposition product that consists of a mixture of fatty acids. The rate of formation of adipocere in a river water environment has been monitored. Adipocere formed from pig adipose tissue has been analysed using gas chromatography mass spectrometry (GCMS ) in order to determine the fatty acid composition, and hence, the degree of formation in the different environments. The study shows that the rate at which adipocere forms depends on the type of aqueous environment

Solid-phase extraction in combination with GC/MS for the quantification of free fatty acids in adipocere

Current research investigating the effect of specific aquatic microenvironments on the formation of adipocere using domesticated pigs (Sus scrofa) has demonstrated the need for a fast and reliable method to separate and identify fatty acids present in adipocere. Adipocere is defined as a late-stage post-mortem decomposition product consisting of a mixture of free fatty acids (FPA), which have formed under favorable conditions due to the hydrolysis of triglycerides in adipose tissue. Whilst good separations of adipocere lipids have been achieved using TLC, this method is time consuming when processing large numbers of samples. This paper describes a rapid and simple method for the extraction, identification and quantification of FFA commonly found in adipocere, by solid-phase extraction (SPE) using aminopropyl disposable columns in combination with GC/MS. The recoveries of FFA associated with adipocere were all above 90%, with coefficients of variation below 10%, indicating that the technique was reproducible. The limits of quantification were registered at levels of parts per million. Standard curves were linear over the range of 50-1000 μg/mL, with all correlation coefficient values greater than 0.998. A marked increase in concentration of saturated fatty acids was observed during adipocere formation, ranging from 20 to 55% for palmitic acid, 13 to 23% for stearic acid and 2.8 to 4.1% for myristic acid. These results demonstrate the suitability of aminopropyl disposable SPE columns to efficiently and rapidly isolate FFA from adipocere prior to quantitative GC/MS analysis. © 2008 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim

The formation of adipocere in model aquatic environments

© 2015, Springer-Verlag Berlin Heidelberg. An examination of the chemistry of adipocere formation in aquatic systems provides insight into how environmental factors affect the decomposition processes of human remains. Gas chromatography–mass spectrometry (GC-MS) and inductively coupled plasma–mass spectrometry (ICP-MS) have been employed to monitor the changes to the chemistry of adipocere formed in aquatic environments used to model seawater, river and chlorinated water systems. Seawater was shown to inhibit adipocere formation, and a distinctively different elemental composition was produced in this environment due to the high concentrations of salts. By comparison, river water has been shown to accelerate the formation of adipocere. Chlorinated water appears to significantly enhance adipocere formation, based on a comparison with established fatty acid concentration values. However, a competing reaction to form chlorohydrins in chlorinated water is believed to be responsible for the unusual findings in this environment. The application of the chemical characterisation of adipocere to an understanding of how this particular decomposition product forms in different water environments has been demonstrated, and there is potential to utilise this approach to identify the environment in which a body has been immersed