Marine taphonomy: adipocere formation in a series of bodies recovered from a single shipwreck.

Taphonomy of marine environments has been studied mostly from individual cases. The formation of adipocere, or "grave-wax," is an important indicator of the postmortem interval. In the present paper, the conditions and the timing of adipoceric formation are observed in a series of 15 cadavers recovered at different times, over a period of 433 days, from the same contained environment. Initial foci of adipocere on the subcutaneous tissue of the cadavers were detected as early as 38 days from the time of immersion in cold (10-12 degrees C) sea water. The discrepancies between our findings and previous reports on the correlation between time since death and decomposition stages in marine environments are discussed.     

Preservation of human tissue immersed for five years in fresh water of known temperature

Two human bodies were recovered from the waters of the Duluth, Minnesota harbor. Extensive adipocere formation resulted in remarkable preservation of gross anatomic features of internal organs. Total time of immersion could be precisely estimated at five years. Water temperature during those five years could also be accurately estimated by direct measurements taken during the year following recovery of the bodies and from information supplied by a local electric power generating company. Immersion occurred at the time of the year when water temperature was highest (70 degrees F [21 degrees C]) facilitating the rapid formation of adipocere. A proposed mechanism for formation of adipocere is described.     

Forensic Use of A Subtropical Blowfly: The First Case Indicating Minimum Postmortem Interval (mPMI) in Southern Brazil and First Record of Sarconesia Chlorogaster from a Human Corpse

Southern Brazil is unique due to its subtropical climate. Here, we report on the first forensic entomology case and the first record of Sarconesia chlorogaster (Wiedemann) in a human corpse in this region. Flies' samples were collected from a body indoors at 20°C. Four species were found, but only Chrysomya albiceps (Wiedemann) and S. chlorogaster were used to estimate the minimum postmortem interval (mPMI). The mPMI was calculated using accumulated degree hour (ADH) and developmental time. The S. chlorogaster puparium collected was light in color, so we used an experiment to establish a more accurate estimate for time since initiation of pupation where we found full tanning after 3 h. Development of C. albiceps at 20°C to the end of the third instar is 7.4 days. The mPMI based on S. chlorogaster (developmental time until the third instar with no more than 3 h of pupae development) was 7.6 days.     

Adipocere formation via hydrogenation of linoleic acid in a victim kept under dry concealment

Adipocere formation is well known as a later post-mortem change. We experienced a female victim who had been sealed up in a clothes box for approximately 4 years. We collected several subcutaneous fats as well as visceral fats from the victim to investigate adipocere formation. Fresh subcutaneous fats of one female and five male victims who suddenly died were used as the control. These samples were homogenized and the lipids were extracted with chloroform and methanol followed by injection into gas chromatography-mass spectrometry and gas chromatography. We detected a hydroxy fatty acid in the fat of the case, but not in the controls. Using standard synthetic hydroxy fatty acid, the lipid extract component was identified as 10-hydroxyoctadecanoic acid (10-OH 18:0) and this concentration was quantified. Consequently we confirmed that adipocere was formed much slowly in dry concealment. In addition, the fatty acid composition was compared with the control. Most of the linoleic acid (18:2) disappeared and a peak developed instead. Using standard synthetic fatty acid, this peak was identified as cis-12-octadecenoic acid (cis-12-18:1). This suggests that linoleic acid is hydrogenated to cis-12-octadecenoic acid in the process of adipocere formation.     

Evidence of adipocere in a burial pit from the foot and mouth epidemic of 1967 using gas chromatography-mass spectrometry

Gas-chromatography-mass spectrometry was used to characterise the fatty acids from soils and associated tissues excavated from a 1967 Foot and Mouth burial pit. Subcutaneous fats were mainly comprised of 55-75% palmitic acid, 17-22% stearic acid and 3-16% oleic acid as well as 5-7% myristic acid. The distribution of fatty acids confirmed that the tissues were decayed to adipocere. The loss of oleic acid to <3% in two of the decayed fats suggested advanced stages of adipocere. However, adipocere formation was limited in a third tissue sample recovered from greater depth. Inductively coupled plasma atomic emission spectrometry of the pore waters revealed a decrease in Ca concentration and concurrent increase in Na concentrations this suggested that insoluble calcium salt had formed through displacement of sodium. The use of fatty acid profiles from soils and soil interstitial pore waters provide complementary evidence of adipocere formation in foot and mouth burial pits.     

The formation of early stage adipocere in submerged remains: a preliminary experimental study

In some circumstances, the presence of adipocere may retard decomposition and complicate postmortem interval estimation. This article explores the correlation between Accumulated Degree Days (ADD) and early stage formation of adipocere. Sixty wild rabbit (Oryctolagus cuniculus) carcasses were used in this experiment; a control group (N = 30) deposited directly on the ground surface and an experimental group (N = 30) completely submersed in water in individual buckets. Data (water and inner body temperature, pH, and total body score) were collected every 100 ADD. Results indicated that early stage adipocere is correlated to ADD and that its formation on submersed remains is more likely to occur after 630 ADD. Skin sloughing promoted the formation of adipocere. No adipocere was formed on any of the control group rabbits. This study also highlights the fact that multiple factors influence adipocere formation and it is suggested that further research needs to be conducted into this area.     

Forensic toxicological study on adipocere formation in submerged cadavers of female albino rats intoxicated with cadmium

There is a dearth of information on the mutual interaction between metal intoxication and adipocere formation. Herein, 40 adult female albino rats were distributed into two equal groups, one used as control while the other orally administered single dose of cadmium chloride (CdCl₂) 225 mg/kg·bw (LD_min). Control group was killed by cervical dislocation. Half of dead rats of both groups were subjected for determination of iodine value and estimation of cadmium (Cd) residues while the other half of both groups were submerged in opened glass container previously filled with 4 L dechlorinated tap water kept in closed room with an open air access (one cadaver/container). Gross morphological changes of submerged cadavers were recorded weekly along the experiment. At the end of the experiment, after 3 months, samples were collected again for iodine value determination and estimation of Cd residues. The obtained results revealed the depressant effect of Cd toxicity on development of adipocere. Cd residues were found in different tissues of cadavers at time of death with the highest amount in the intestines followed by the liver and kidneys, then lungs, adipose tissue, muscles, and finally the bones. After 3 months of water submersion, tissues exhibited significant decrease in the amount of Cd residues but to a limit that was still detected. This study concluded the possibility of detection of Cd residues even after adipocere formation. Additionally, it shed light on the possibility of the interference of environmental pollution with the natural rate of decomposition especially adipocere formation.     

Retrospective analysis of factors affecting rate of skeletonization within a tropical climate

Estimating the post mortem interval (PMI) in skeletonized cases is an extremely challenging exercise. Sri Lanka lacks adequate taphonomic research which is a serious limitation when assessing PMI in forensic death investigations. Methods that have been proposed to estimate PMI using the total body score (TBS) and accumulated degree days (ADD) are mainly based on data from continental and temperate climates and have shown less reliability in tropical climates. With the intention of developing a region-specific, evidence-based guide which would be applicable to tropical climates like Sri Lanka, we selected thirteen skeletonized remains with known PMIs from forensic case records and analysed their taphonomy in relation to selected weather data. We also compared the ADD values within our dataset with reference ranges calculated using published formula.All except one were found from outdoor locations. The TBS ranged from 24 to 32 and had a weak positive correlation with the PMI. The earliest appearance of skeletonization was 15 days in a body found indoors. The highest rate of skeletonization was seen in a body with a TBS of 32 and a PMI of 23 days. The average daily temperature and relative humidity were similar across all the cases however, the amount of rainfall varied. Bodies exposed to monsoon rains (n = 6) had a lower mean rate of skeletonization compared to those that were not exposed (n = 4) suggesting lower rates of decomposition during periods of heavy rainfall.No correlation was found between ADD and TBS. In 9 (69.2%) cases, the actual ADD was much lower than reference ADD ranges for TBS values, indicating poor applicability of TBS and ADD based formulae in estimating PMI within the Sri Lankan climate. Our study shows a strong need for taphonomic and entomological research in tropical climates to further explore the impact of monsoons on biotic and abiotic factors affecting skeletonization.     

The Initial Changes of Fat Deposits During the Decomposition of Human and Pig Remains

Abstract:  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.     

The effect of the burial environment on adipocere formation

Adipocere is a decomposition product comprising predominantly of saturated fatty acids which results from the hydrolysis and hydrogenation of neutral fats in the body. Adipocere formation may occur in various decomposition environments but is chiefly dependent on the surrounding conditions. In a soil burial environment these conditions may include such factors as soil pH, temperature, moisture and the oxygen content within the grave site. This study was conducted to investigate the effect of these particular burial factors on the rate and extent of adipocere formation. Controlled laboratory experiments were conducted in an attempt to form adipocere from pig adipose tissue in model burial environments. Infrared spectroscopy, inductively coupled plasma-mass spectrometry, and gas chromatography-mass spectrometry were employed to determine the lipid profile and fatty acid composition of the adipocere product which formed in the burial environments. The results suggest that adipocere can form under a variety of burial conditions. Several burial factors were identified as enhancing adipocere formation whilst others clearly inhibited its formation. This study acts as a preliminary investigation into the effect of the burial environment on the resultant preservation of decomposing tissue via adipocere formation.     

The effect of the method of burial on adipocere formation

A controlled laboratory experiment was conducted in order to investigate the effect of the method of burial (i.e. the presence of coffin and clothing) on the formation of adipocere. This study follows previous studies by the authors who have investigated the effect of physical conditions on the formation of adipocere present in a controlled burial environment. The study utilises infrared spectroscopy to provide a preliminary lipid profile of the remains following a 12 month decomposition period. Inductively coupled plasma-mass spectrometry was employed as a technique for determining the salts of fatty acids present in adipocere. Gas chromatography-mass spectrometry (GC-MS) was used as the confirmatory test for the identification and determination of the chemical composition of adipocere which formed in the controlled burial environments. The results suggest that coffins will retard the rate at which adipocere forms but that clothing enhances its formation. The results concur with previous observations on adipocere formation in burial environments.     

Postmortem changes of human bodies on the bathyal sea floor--two cases of aircraft accidents above the open sea

Forensic taphonomy in the marine context recently received growing attention. However, only limited information is available about the fate of human bodies at greater sea depth. Following two fatal aircraft accidents (west of Namibia, south of Sicily) human remains were recovered from a depth of 540-580 m (both cases) after 3 months (Namibia)/34 days (Sicily). In the Namibia case fully skeletonized bones were lifted. In the Sicily case a complete, dressed body was found exhibiting a partially skeletonized skull, starting adipocere formation and pink teeth. The rate and mode of decomposition of human bodies in the deep sea varies considerably and is mainly influenced by the local faunal composition. Of special relevance for the understanding of both cases was the oceanographic observation that the highly efficient necrophageous lyssianassids are abundant off Namibia but are rare in the Mediterranean, emphasizing the importance of collaboration of forensic and marine scientists in such case work.     

Modern concepts of adipocere formation mechanisms

Biochemical parameters of transformation of fresh subcutaneous fat into adipocere have been studied in experiment. Activation of lipid peroxidation is a significant component of the mechanism of adipocere transformation, which is proven by a drastic increase in the level of Schiff's bases in adipocere in comparison with subcutaneous fat. The concentrations of myristic, palmitic, and stearic fatty acids increase during the formation of adipocere, while the content of linoleic acid decreases in comparison with the unchanged human subcutaneous fat.     

Chemical Analysis in the Corpus Callosum Following Traumatic Axonal Injury using Fourier Transform Infrared Microspectroscopy: A Pilot Study

Evaluating traumatic axonal injury remains challenging in clinical and forensic sciences as its identification is difficult using routine diagnostic methods. This study used Fourier transform infrared microspectroscopy to detect TAI within the corpus callosum in an animal model. Protein conformational analysis revealed significantly increased β-sheet and β-turn contents paralleled by a decrease in α-helix content at 24 h postinjury, while the antiparallel β-sheet content was decreased at 12 h postinjury. Compared with the control group, the lipid/protein ratio was significantly reduced in all of the injured groups. At 24 h postinjury, there were increases in the olefinic=CH and CH₃ group of lipids accompanied by the decreased CH₂ group, but the results at 12 and 72 h were contrary to that at 24 h. Our study showed that FTIRM could differentiate injured from normal white matter at different time points following TBI via examination of these infrared spectral parameters.     

Evaluating the use of hypoxia sensitive markers for body fluid stain age prediction

To augment DNA profiling and body fluid identification techniques efforts are being made to increase the amount of information available from a crime scene stain, which includes efforts to identify externally visible characteristics through phenotypic analysis. A key question surrounding crime scene stains is the length of time between deposition of the stain and its subsequent recovery, in that is the stain recovered related to the incident in question or from a previously deposited stain number of weeks earlier? The inability to answer this fundamental question has a detrimental effect upon the successful completion of a criminal investigation. Once a body fluid leaves the body, the oxygen concentration in the environment changes; therefore, it may be that this change could cause a change in the expression of hypoxia-sensitive biomarkers. Here, a range of bloodstains, liquid saliva and liquid semen samples were collected at 0 days, 7 days, 14 days, 21 days and 28 days of degrading at room temperature (19–22 °C), before undergoing total RNA extraction and cDNA synthesis. Blood was recovered from filter paper with 3 mm², with saliva and semen being left in their tubes and swabbed at the appropriate times. All samples then underwent quantitative PCR targeting Vascular Endothelial Growth Factor A (VEGFA) and Hypoxia-Inducible Factor 1 Alpha (HIF1A), with B-Actin (ACTB) as a reference gene. A range of linear and quadratic correlation values was obtained from the qPCR data and used to develop a predictive model with a mean absolute deviation (MAD) of 4.2, 2.1, and 5 days for blood, saliva, and semen respectively. Blind testing indicated that a stain age prediction model based upon VEGFA with ACTB as a reference gene could be used on samples up to four weeks old with a margin of error ranging from 2 days through to 5 days. While a sizeable potential time frame exists using this model; this represents a significant step towards the target of having an accurate stain age prediction model.     

Postmortem red coloration of teeth. A retrospective investigation of 26 cases

Postmortem red coloration of teeth (pink teeth) was found in 26 of 119 consecutive autopsy or forensic dental identification cases during 1973-1984. The present study confirms that red coloration of teeth may occur some time after death under conditions that promote putrefaction and adipocere formation. The red coloration is due to hemolysis after exudation of hemoglobin derivatives through the dentine tubules in cases in which blood has accumulated in the head, either due to congestion or by a postmortem head-down position, as after submersion in water.     

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.     

Gross and histologic postmortem changes of the skin

Many methods have been attempted to accurately and systematically determine the estimated time of death in autopsy cases. Gross changes of the skin which occur during the postmortem interval have occasionally been used to estimate the time of death under different conditions; however, the postmortem gross and histologic changes of the skin have not been systematically analyzed. We sequentially studied the gross and microscopic appearance of skin in 3 individuals during the early postmortem interval (<1 week) in an outdoor, shaded, cool to temperate climate. Photos and skin biopsy specimens were taken from 4 sites (acral skin, scalp, dependent truncal skin, and nondependent truncal skin) every 12-24 hours on each individual. The gross appearance of the skin remarkably did not change significantly in any of the sites after 1 week of decomposition. Three main histologic changes were seen in the skin biopsy specimens: focal dermal-epidermal separation, eccrine duct necrosis, and dermal degeneration. Although bullae were not present in the gross examination of the skin, focal separation of the epidermis from the dermis was appreciated in several skin biopsies; however, the timing of development was unpredictable. Eccrine duct necrosis was another histologic finding and was relatively predictable, occurring in dependent and nondependent truncal skin biopsies from all 3 individuals between days 4 and 7. Dermal degeneration was a uniform histologic finding only in biopsies from nondependent truncal skin, occurring in all individuals on day 2. Although this study is limited by the small number of subjects and uncontrolled extrinsic factors, histologic findings, such as eccrine gland necrosis and dermal degeneration, in select cutaneous biopsies may be useful in estimating the time of death in the early postmortem interval.     

Preliminary quantitative investigation of postmortem adipocere formation

The accurate determination of postmortem interval (PMI) using the formation of adipocere presents a significant challenge to forensic scientists interested in determining the time of death. Several attempts have been made to determine the time since the occurrence of death. However, up to date, this has been difficult because previous approaches have been mainly qualitative, focusing on the later stages of degradation processes. This work presents preliminary results of an experimental model of postmortem adipocere formation using liquid chromatography. Three pig cadavers were submerged in distilled water, chlorinated water, and saline water. Fresh specimens resulting from the degradation in the subcutaneous fat were obtained from the pigs at two-week intervals for a period of ten weeks, and were subjected to chromatographic analysis. By correlating the ratio of the disappearance of hydrolyzed fatty acids with the formation of hydroxystearic and oxostearic acids after death, a simple, quantitative analytical method was developed for the determination of PMI. Experimental observation of the chemistry of adipocere formation indicated that adipocere can be formed only a few hours after an incidence of death and this continues until the saturation of oleic acid degradation after several weeks. Different time courses were obtained for cadavers immersed in distilled, chlorinated, and saline water, respectively. This work has not in any way solved the time since death problem. But it may be an approach to the problem that has not been adequately explored.