Forensic wound examination

Review of the current and potential use of biological and molecular methods for the estimation of the postmortem interval in animals and humans

We provide here an overview of the state of applied techniques in the estimation of the early period of the postmortem interval (PMI). The biological methods included consist of body cooling, CSF potassium, body cooling combined with CSF potassium, and tissue autolysis. For each method, we present its application in human and veterinary medicine and provide current methodology, strengths, and weaknesses, as well as target areas for improvement. We examine current and future molecular methods as they pertain to DNA and primarily to messenger RNA degradation for the estimation of the PMI, as well as the use of RNA in aging wounds, aging blood stains, and the identification of body fluids. Various types of RNA have different lengths, structures, and functions in cells. These differences in RNAs determine various intrinsic properties, such as their half-lives in cells, and, hence, their decay rate as well as their unique use for specific forensic tests. Future applications and refinements of RNA-based techniques provide opportunities for the use of molecular methods in the estimation of PMI and other general forensic applications.

Detection of multiple biomarkers associated with satellite cell fate in the contused skeletal muscle of rats for wound age estimation

From the perspective of forensic wound age estimation, experiments related to skeletal muscle regeneration after injury have rarely been reported. Here, we examined the time-dependent expression patterns of multiple biomarkers associated with satellite cell fate, including the transcription factor paired box 7 (Pax7), myoblast determination protein (MyoD), myogenin, and insulin-like growth factor (IGF-1), using immunohistochemistry, western blotting, and quantitative real-time PCR in contused skeletal muscle. An animal model of skeletal muscle contusion was established in 30 Sprague-Dawley male rats, and another five rats were employed as non-contused controls. Morphometrically, the data obtained from the numbers of Pax7 + , MyoD + , and myogenin + cells were highly correlated with the wound age. Pax7, MyoD, myogenin, and IGF-1 expression patterns were upregulated after injury at both the mRNA and protein levels. Pax7, MyoD, and myogenin protein expression levels confirmed the results of the morphometrical analysis. Additionally, the relative quantity of IGF-1 protein > 0.92 suggested a wound age of 3 to 7 days. The relative quantity of Pax7 mRNA > 2.44 also suggested a wound age of 3 to 7 days. Relative quantities of Myod1, Myog, and Igf1 mRNA expression > 2.78, > 7.80, or > 3.13, respectively, indicated a wound age of approximately 3 days. In conclusion, the expression levels of Pax7, MyoD, myogenin, and IGF-1 were upregulated in a time-dependent manner during skeletal muscle wound healing, suggesting the potential for using them as candidate biomarkers for wound age estimation in skeletal muscle.

Novel insights into wound age estimation: combined with "up, no change, or down" system and cosine similarity in python environment

Wound age estimation is a complex, multifactorial issue. It is considered to have great practical significance that combining multi-biomarkers and multi-methods for injury time estimation. We optimized our earlier "up, no change, or down" model by adding data on the expression levels of mRNAs encoding ABHD2, MAD2L2, and ARID5A, and we converted the relative quantitative expression levels of seven genes into a vector rather than a color model. We used Python to derive the cosine similarity (CS) between a test set and the vector matrix; the highest similarity most accurately reflected the injury time. For the optimized model, the internal and external verifications were approximately 0.71 and 0.66, respectively. The good double-blinded results indicated that the model was stable and reliable. In summary, we used a vector matrix and cosine similarities derived by Python to mine the levels of genes expressed in contused skeletal muscle. We are the first to combine several biomarkers and methods for wound age estimation.

Regulation of miRNAs as new tool for cutaneous vitality lesions demonstration in ligature marks in deaths by hanging

This study aims to demonstrate that the application of miRNA expression in forensic pathology, in cases of hanging, applying the method on skin samples. The proposed investigative protocol allowed us to highlight a different miRNA expression in the skin ligature marks of subjects who died by hanging compared to healthy skin control samples. The results obtained showed an increase in the expression of miRNAs recognized as regulators of the inflammatory response in skin lesions such as miR125a-5p and miR125b-5p. Furthermore, overexpression of additional miRNAs - miR214a-3p, miR128-3p, miR130a-3p, and miR92a-3p - with anti-inflammatory activity was highlighted. It was possible to document a statistical significance to control skin samples only for miR103a-3p (p < 0.05), miR214-3p and miR92a-3p (p < 0.01) The upregulation of miR222-3p and miR150-5p, respectively related to mast-cell activation and neutrophils after the application of traumatic stimuli supports the immunohistochemical data showed in literature. The diagnostic accuracy of miRNAs could expand the range of diagnostic tools available in the assessment of the vitality of a lesion.

Determination of skin wound age by using cytokines as potential markers

Interleukin-1 beta (IL-1β), IL-6, tumour necrosis factor-alpha (TNF-α) and epidermal growth factor (EGF) play important roles in the wound healing process. In the present study, human wound specimens (n = 50) were collected from cases of death due to injuries from firearms, penetrating trauma by sharp objects and blunt trauma with a known time of injury and death identified by forensic autopsy. Full-thickness tissue specimens were obtained from injured skin sites, and equally sized intact tissues obtained from the same person were used as controls. Protein determination was performed using ELISA according to the Bradford method for each specimen, and results were provided for individual proteins. IL-1β levels did not reach statistical significance in any of the wound groups and were not markedly higher than those in the control group. However, IL-6 showed a biphasic pattern and reached statistical significance in the group with wounds less than 30 min old and in the group with wounds more than 18 h old. IL-6 was consistently higher in all wound groups than in the control group. TNF-α showed a statistically significant increase within the first 30 min and remained at a high level in all groups except for those with wounds 2-4 h old. On the other hand, EGF was high in all groups excluding those with wounds 2-4 h old and more than 18 h old, but statistical significance was not reached. Our results suggest that IL-6 and TNF-α in particular may be used as early-phase markers. We believe that IL-1β and EGF should be more extensively evaluated in further studies.

Immunohistochemical detection of CD14 and combined assessment with CD32B and CD68 for wound age estimation

Estimation of wound age is a major topic of study for forensic pathologists, but few markers exist that can indicate a specific period 1-5 days postinfliction, and a method to estimate wound age with high accuracy has not yet been established. This study examined CD14 as such a marker in mouse skin wounds of different ages (0min and 1, 2, 3, 5, 7, and 9 days) and in human subjects (group 1, 0-1 day; group 2, 1-5 days; group 3, >7 days) using Western blot analysis and/or immunohistochemical staining. In addition, we evaluated a combination of immunohistochemical markers in human skin wounds using transmembrane proteins, CD14, CD32B, and CD68, expressed on inflammatory cells. The expression of CD14 was detected only during 1-5 days postinfliction and, thus, the evaluation of CD14-expressing cells could specify wound age during 1-5 days postinfliction in mouse skin wounds. The ratio of samples assessed to be CD14(+) was significantly high in human skin wounds in group 2. Combined assessment using the three markers increased the specificity of diagnosis and shortened the range of wound age, compared with the assessment using a single marker. Our results indicate that CD14 may be a useful marker of wound age, 1-5 days postinfliction, and that combined assessment with CD14, CD32B, and CD68 may be a good method for the accurate estimation of wound age.

Detection of endothelial progenitor cells in human skin wounds and its application for wound age determination

Endothelial progenitor cells (EPCs), a newly identified cell type, are bone marrow-derived progenitor cells that co-express stem cell markers and vascular endothelial growth factor (VEGF) receptor (Flk-1). In this study, a double-color immunofluorescence analysis was carried out using anti-CD34 and anti-Flk-1 antibodies to examine the time-dependent appearance of EPCs, using 52 human skin wounds with different wound ages (Group I, 0-1 days; Group II, 2-6 days; Group III, 7-14 days; and Group IV, 17-21 days). In wound specimens with an age of less than one day, CD34(+)/Flk-1(+) EPCs were not detected. EPCs were initially observed in wounds aged two days, and their number was increased in lesions with advances in wound age. In morphometrical analysis, the average number of EPCs was the highest in the wounds of Group III. Especially, 20 out of 21 wounds aged 7-12 days had >20 EPCs, and all wound samples with postinfliction intervals of 14-21 days had <15 EPCs. These observations at least showed that >20 EPCs would indicate a wound age of 7-12 days. Taken together, our observations indicate the detection of EPCs would be useful for wound age determination.

The time-dependent expression of α7nAChR during skeletal muscle wound healing in rats

The study on time-dependent expression of α7 nicotine acetylcholine receptor (α7nAChR) was performed by immunohistochemistry, Western blotting, and real-time PCR during skeletal muscle wound healing in rats. Furthermore, co-localization of α7nAChR with macrophage or myofibroblast marker was detected by double immunofluorescence. A total of 50 Sprague-Dawley male rats were divided into control and contusion groups (3 h, 6 h, 12 h, 1 day, 3 days, 5 days, 7 days, 10 days, and 14 days post-injury). In the uninjured controls, α7nAChR positive staining was observed in the sarcolemma and sarcoplasm of normal myofibers. In wounded specimens, a small number of polymorphonuclear cells, a number of macrophages and myofibroblasts showed positive reaction for α7nAChR in contused zones. Morphometrically, the average ratios of α7nAChR-positive cells were over 50 % from 3 to 10 days after contusion, and exceeded 60 % at 5 and 7 days post-injury. Besides, the positive ratios of α7nAChR were <50 % at the other posttraumatic intervals. By Western blotting analysis, the average ratio of α7nAChR protein expression maximized at 7 days after injury, which was >2.13. Similarly, the relative quantity of α7nAChR mRNA expression peaked at 7 days post-wounding as compared with control by real-time PCR detection, showing a relative quantity of >2.65. In conclusion, the expression of α7nAChR is upregulated and temporally distributed in macrophages and myofibroblasts during skeletal muscle wound healing, which might be closely involved in inflammatory response and fibrotic repair after injury. Moreover, α7nAChR is promising as a useful marker for wound age determination of skeletal muscle.

Forensic molecular pathology: its impacts on routine work, education and training

The major role of forensic pathology is the investigation of human death in relevance to social risk management to determine the cause and process of death, especially in violent and unexpected sudden deaths, which involve social and medicolegal issues of ultimate, personal and public concerns. In addition to the identification of victims and biological materials, forensic molecular pathology contributes to general explanation of the human death process and assessment of individual death on the basis of biological molecular evidence, visualizing dynamic functional changes involved in the dying process that cannot be detected by morphology (pathophysiological or molecular biological vital reactions); the genetic background (genomics), dynamics of gene expression (up-/down-regulation: transcriptomics) and vital phenomena, involving activated biological mediators and degenerative products (proteomics) as well as metabolic deterioration (metabolomics), are detected by DNA analysis, relative quantification of mRNA transcripts using real-time reverse transcription-PCR (RT-PCR), and immunohisto-/immunocytochemistry combined with biochemistry, respectively. Thus, forensic molecular pathology involves the application of omic medical sciences to investigate the genetic basis, and cause and process of death at the biological molecular level in the context of forensic pathology, that is, 'advanced molecular autopsy'. These procedures can be incorporated into routine death investigations as well as guidance, education and training programs in forensic pathology for 'dynamic assessment of the cause and process of death' on the basis of autopsy and laboratory data. Postmortem human data can also contribute to understanding patients' critical conditions in clinical management.

Long-term RNA persistence in postmortem contexts

Ribonucleic acids (RNA) are generally considered fragile molecules that are readily degraded. However, there is growing documentation of long-term (from days to centuries) RNA persistence in a variety of contexts and tissue types, and as such a number of academic disciplines are beginning to exploit degraded RNA. While the reasons for its survival are not fully understood, there are several plausible mechanisms that would safeguard this molecule against degradation. However, after examining the literature available on the postmortem instability and decay mechanisms of RNA, it has become clear that limited experimental studies and no reviews offer an overview of these mechanisms. Hence in this review we outline molecular reasons for RNA surviving long-term postmortem, and provide specific examples of RNA survival in forensic, archival and archaeological contexts. A better understanding of the mechanisms of RNA decay will be crucial for developing expectations on its long-term survival.

Some challenges in forensic veterinary pathology: a review

Forensic veterinary pathology is a diverse discipline that is in an early phase of its development. Common challenges include estimation of the age of skin wounds and bruises, the diagnosis of drowning and estimation of the time since death. However, many details of the pathological findings related to these various aspects await validation. The 'multispecies' nature of veterinary pathology, combined with the preponderance of published observations originating from animal experimentation, rather than casework, poses two challenges. Firstly, extrapolation of results between species may jeopardize the reliability (and credibility) of the forensic opinion. Secondly, experimental studies may not truly reflect the spectrum of changes seen in actual cases (e.g. extent of injuries, infection, age and health of victim). With regard to drowning, diagnosis based on post-mortem findings remains problematical. Methods for estimation of the time since death (also known as the post-mortem interval) continue to be a major focus of study, with fresh avenues such as post-mortem diagnostic imaging offering interesting possibilities.

Histological analysis of short-term vital reactions in skin wounds: potential applications in forensic work

In forensic medical work, in cases with homicide suspicion, it is important to be able to determine with the greatest possible precision when injuries occurred and whether during vital, or post-mortem conditions. Although several markers of vitality can be employed, it has been attested that components of the extra-cellular matrix, such as fibrin, are among the earliest to be evidenced. In the present study, the histological-histochemical Mallory's Trichrome staining method, previously selected was tested to determine the presence of vital reaction in Wistar rats through fibrin accumulation by testing three short reaction time intervals: 15, 30 and 60 minutes after the skin wound infliction. For all time intervals tested, including the shortest (15 minutes), the presence of fibrin at the edges of the skin wound was evidenced. The accumulation of fibrin was, nevertheless, more pronounced at 30 and 60 minutes after the wound. It could be concluded that fibrin is a good marker for vital reaction and that it can be detected very early, within a few minutes after the injury. It is proposed that histological method coupled to the histochemical staining technique here tested can be incorporated into routine forensic work as a tool for evidencing the existence or not of vital reaction.

The use of the anti-Glycophorin A antibody in the detection of red blood cell residues in human soft tissue lesions decomposed in air and water: a pilot study

The distinction between antemortem and postmortem wounds is one of the most important medico-legal problems. In fresh cadavers the macroscopic examination of haemorrhagic infiltration can be sufficient to reveal the vitality of a wound but in more difficult cases (putrefied corpses) histological and histochemical analyses need to be performed. The scope of this study was to detect the vitality of soft tissue samples in an advanced state of putrefaction using a monoclonal anti-human Glycoforin A antibody in order to evaluate the presence of red blood cells or red blood cell residues. Samples of skin wounds were taken from cadavers with a known time survival between trauma and death, and then submitted to a simulated putrefaction procedure. The skin samples were left to decompose for 30 days in air and in water and analyzed at a time interval of 3-6-15-30 days. These samples were stained with haematoxylin eosin stain, trichrome stain and with immunohistochemical stains. Results showed that in the air red blood cells could be seen for up to six days and granular deposits of Glycophorin reactive material for up to 15 days whereas no red blood cells were recognizable after 30 days. In water red cell putrefaction (or non-detection) was faster than in the air: after six days only amorphous granular deposits slightly reactive to Glycophorin could be seen. Nonetheless results showed that extravasated red blood cell residues can still be detected in skin bruises left to decompose in air and water, for up to at least 15 days in the open air and one week in water.

Phosphoprotein stability in clinical tissue and its relevance for reverse phase protein microarray technology

Phosphorylated proteins reflect the activity of specific cell signaling nodes in biological kinase protein networks. Cell signaling pathways can be either activated or deactivated depending on the phosphorylation state of the constituent proteins. The state of these kinase pathways reflects the in vivo activity of the cells and tissue at any given point in time. As such, cell signaling pathway information can be extrapolated to infer which phosphorylated proteins/pathways are driving an individual tumor's growth. Reverse phase protein microarrays (RPMAs) are a sensitive and precise platform that can be applied to the quantitative measurement of hundreds of phosphorylated signal proteins from a small sample of tissue. Pre-analytical variability originating from tissue procurement and preservation may cause significant variability and bias in downstream molecular analysis. Depending on the ex vivo delay time in tissue processing, and the manner of tissue handling, protein biomarkers such as signal pathway phosphoproteins will be elevated or suppressed in a manner that does not represent the biomarker levels at the time of excision. Consequently, assessment of the state of these kinase networks requires stabilization, or preservation, of the phosphoproteins immediately post-tissue procurement. We have employed RPMA analysis of phosphoproteins to study the factors influencing stability of phosphoproteins in tissue following procurement. Based on this analysis we have established tissue procurement guidelines for clinical research with an emphasis on quantifying phosphoproteins by RPMA.

Tissue is alive: New technologies are needed to address the problems of protein biomarker pre-analytical variability

Instability of tissue protein biomarkers is a critical issue for molecular profiling. Pre-analytical variables during tissue procurement, such as time delays during which the tissue remains stored at room temperature, can cause significant variability and bias in downstream molecular analysis. Living tissue, ex vivo, goes through a defined stage of reactive changes that begin with oxidative, hypoxic and metabolic stress, and culminate in apoptosis. Depending on the delay time ex vivo, and reactive stage, protein biomarkers, such as signal pathway phosphoproteins will be elevated or suppressed in a manner which does not represent the biomarker levels at the time of excision. Proteomic data documenting reactive tissue protein changes post collection indicate the need to recognize and address tissue stability, preservation of post-translational modifications, and preservation of morphologic features for molecular analysis. Based on the analysis of phosphoproteins, one of the most labile tissue protein biomarkers, we set forth tissue procurement guidelines for clinical research. We propose technical solutions for (i) assessing the state of protein analyte preservation and specimen quality via identification of a panel of natural proteins (surrogate stability markers), and (ii) using multi-purpose fixative solution designed to stabilize, preserve and maintain proteins, nucleic acids, and tissue architecture.

Wound age estimation by simultaneous detection of 9 cytokines in human dermal wounds with a multiplex bead-based immunoassay: an estimative method using outsourced examinations

Wound age estimation for human dermal wounds was performed based on quantification of interleukin 1beta (IL 1beta), IL 5, IL 7, IL 12 p70, IL 13, IL 17, granulocyte colony-stimulating factor (G-CSF), monocyte chemoattractant protein 1 (MCP 1), and macrophage inflammatory protein 1beta (MIP 1beta). IL 5, IL 12 p 70, IL 13, and IL 17 increased from the early phase, MCP 1 exclusively in the middle phase, and IL 1beta, G-CSF, and MIP 1beta from the middle phase to the late phase. IL 7 decreased from the early phase. Among the cytokines analyzed in the present study, MCP 1 was the most plentiful cytokine. In addition, an outsourced examination, which could be available to any forensic institute, was performed in two cases for confirmative purposes. Many factors have been proposed as markers for dermal wound age estimation, but the set of cytokines selected for the outsourced examination in the present study wound be useful in daily forensic practice.

Simultaneous detection of eight cytokines in human dermal wounds with a multiplex bead-based immunoassay for wound age estimation

We performed quantification of IL 2, IL 4, IL 6, IL 8, IL 10, GM-CSF, IFN gamma, and TNF alpha in human dermal wounds for wound age estimation. The proliferation of dermal cells and infiltration of inflammatory cells were also analyzed. Neutrophils and macrophages were detected from 2 h post-injury, and strong infiltrations were seen at 33-49 h. T and B lymphocytes also infiltrated simultaneously from 71 h. Strong proliferation of fibroblasts were shown from 246 h, and thickening of the epidermis from 71 h. IL 10, GM-CSF, IFNgamma, and TNF alpha increased from the early phase of dermal wound healing, IL 6 exclusively in the middle phase, IL 2, IL 4, and IL 8 from the middle phase to the late phase. Among the cytokines analyzed in the present study, IL 6, IL 8, IFNgamma, and TNF alpha were strongly expressed. Results of the present study suggest that multiplex cytokine analysis at the wound site can be useful for wound age estimation. In addition, multiplex data obtained from the same sample with a single method would demonstrate more accurate interactions of cytokines during dermal wound healing. Although the present study was oriented to practical forensic pathology, the data obtained would be informative for various fields of medicine.

The biomechanical modelling of non-ballistic skin wounding: blunt-force injury

Knowledge of the biomechanical dynamics of blunt force trauma is indispensable for forensic reconstruction of a wounding event. In this study, we describe and interpret wound features on a synthetic skin model under defined laboratory conditions. To simulate skin and the sub-dermal tissues we used open-celled polyurethane sponge (foam), covered by a silicone layer. A drop tube device with three tube lengths (300, 400, and 500 mm), each secured to a weighted steel scaffold and into which a round, 5-kg Federal dumbbell of length 180 mm and diameter 8 cm was placed delivered blows of known impact. To calculate energy and velocity at impact the experimental set-up was replicated using rigid-body dynamics and motion simulation software. We soaked each foam square in 500 mL water, until fully saturated, immediately before placing it beneath the drop tube. We then recorded and classified both external and internal lacerations. The association between external wounding rates and the explanatory variables sponge type, sponge thickness, and height were investigated using Poisson regression. Tears (lacerations) of the silicone skin layer resembled linear lacerations seen in the clinical literature and resulted from only 48.6% of impacts. Poisson regression showed there was no significant difference between the rate of external wounding for different sponge types (P = 0.294) or different drop heights (P = 0.276). Most impacts produced "internal wounds" or subsurface cavitation (96%). There were four internal "wound" types; Y-shape (53%), linear (25%), stellate (16%), and double crescent (6%). The two-way interaction height by sponge type was statistically significant in the analysis of variance model (P = 0.035). The other two-way interactions; height by thickness and sponge type by thickness, were also bordering on statistical significance (P = 0.061 and P = 0.071, respectively). The observation that external wounds were present for less than half of impacts only, but that nearly all impacts resulted in internal wounds, might explain the observed haematoma formation and contusions so often associated with blunt-force injuries. Our study also confirms the key role of hydrodynamic pressure changes in the actual tearing of subcutaneous tissue. At the moment and site of impact, transferred kinetic energy creates a region of high pressure on the fluid inside the tissue. As a result of the incompressibility of the fluid, this will be displaced away from the impact at a rate that depends on the velocity (or kinetic energy) of impact and the permeability and stiffness of the polymeric foam and skin layer.

A study on mRNA expressions of fibronectin in dermal and cerebral wound healing for wound age estimation

We investigated mRNA expressions of fibronectin for wound age estimation during dermal and cerebral wound healing. Fibronectin mRNA expressions in the injured skin peaked at 8h post-injury. The expressions were detected in endothelial cells before and after injury, whereas they were detectable in the epidermal cells at 1-240 h, in fibroblasts at 1-72 h, in neutrophils and macrophages at 8-72 h, respectively. However, the expressions in epidermal cells became relatively weak in the subacute phase. Fibronectin mRNA expressions of the injured cerebrum increased after the intervention and peaked at 48 h, whereas there was a slight decrease during 24h post-injury. Although fibronectin mRNA was seen exclusively in the endothelial cells of the intact cerebrum, it was also detected in astrocytes during wound healing. From these findings, it was considered that fibronectin played an important role in dermal and cerebral wound healing. Expression of fibronectin mRNA was considered to indicate the acute phase of dermal wound healing, and the subacute phase of cerebral wound healing.

Time-course changes in the expression of heme oxygenase-1 in human subcutaneous hemorrhage

To determine the time-course of human subcutaneous hemorrhage, heme oxygenase (HO)-1 expression and macrophage infiltration were observed using an immunohistochemical technique and semiquantitative analysis. The number of immunoreactive cells and the number of all infiltrating cells of each microscopic field were counted, and the ratio of the former to the latter was calculated as the positive cells ratio. An increase in the HO-1-positive cells ratio was observed starting at 3 h after injury, and the maximum ratio was observed 3 days after injury. The pattern of the increase in the macrophage ratio was similar to that of the HO-1-positive cells ratio in the early period after injury. Observation of serial sections revealed that the expression of HO-1 in the cells corresponded to the localization of macrophage. The present results suggest that the determination of HO-1 expression, as derived from macrophages, might be useful for the estimation of the time-course of subcutaneous hemorrhage.

Expression of fibronectin suicidal in gunshot wounds

Fibronectin has been proposed as the reliable marker of wound vitality and potent tool for age estimation in cases where survival time is at least few minutes. Cases of suicidal gunshot wounds were divided into two groups according to projectile energy and damage of the vital structures. Immunohistochemical reaction on fibronectin was evaluated with semiquantitative scale, which included sum of intensity and widespread of the reaction. Mann-Whitney test has shown statistical significant difference between groups (P< or =0.001).

Albumin as a marker of plasma transudation in experimental skin lesions

Liquid chromatography measurements of albumin levels were obtained for experimental incision wounds, excoriations, and heat and freezing injuries of different ages. Hemoglobin levels in tissue specimens were measured and an equivalent amount of blood-related albumin was subtracted from the analysis results. In specimens taken immediately after death, the mean albumin level as compared to control skin was increased by about 2-fold in freezing injuries aged 60 min. In all other lesions, the same increase was observed even after 30 min. The mean albumin level was about 3-fold as compared with the control skin in excoriations aged 30 min, heat and freezing injuries aged 4 h, and incision wounds aged 12 h. An approximately 5-fold increase was seen in heat and freezing injuries aged 1 and 2 weeks. A marked decrease occurred in mean albumin levels in all lesions aged 4 weeks. An increase in albumin in wounds and excoriations was demonstrable also in specimens taken 3 days postmortem. Postmortem hypostasis resulted in a 1.1 to 1.4-fold increase in mean albumin levels in wounds and excoriations inflicted 1 min postmortem.

Immunohistochemical detection of chemokines in human skin wounds and its application to wound age determination

Immunohistochemical studies on the time-dependent expression of the chemokines such as interleukin (IL)-8, monocyte chemoattractant protein (MCP)-1 and macrophage inflammatory protein (MIP)-1alpha were performed on 50 human skin wounds with different wound ages (group I 0-12 h, group II 1-4 days, group III 7-14 days and group IV 17-21 days). In the wound specimens with wound ages between 4 and 12 h, neutrophils mainly showed positive reactions for IL-8, MCP-1 and MIP-1alpha. With increasing wound ages, macrophages and fibroblasts were positively stained with anti-IL-8, MIP-1alpha and MCP-1 antibodies. Morphometrically, there was a similar distribution in the positive ratios of the inflammatory cells among IL-8, MCP-1 and MIP-alpha. The positive ratios of each chemokine were very low in group I and a considerable increase of the positive ratios in each chemokine was observed in group II (mean +/- standard error IL-8: 59.8 +/- 2.1%, MCP-1: 42.4 +/- 3.1% and MIP-1alpha: 50.4 +/- 3.7%). Although the positive ratios for each chemokine gradually decreased according to the wound age, the mean positive ratios in groups III and IV were significantly higher than those in group I. From the forensic aspect, these chemokines are considered useful markers for wound age determination. Thus, ratios of > 50% for IL-8, > 30% for MCP-1 or > 40% for MIP-1alpha indicate a wound age of at least I day. Moreover, the combined investigation of these three chemokines can make wound age determination more objective and accurate.