Temporal course of intravital and postmortem proliferation of epidermal cells after mechanical injury. An immunohistochemical study using bromodeoxyuridine in rats

Bone Marrow-Derived Cells and Wound Age Estimation

Appropriate technology as well as specific target cells and molecules are key factors for determination of wound vitality or wound age in forensic practice. Wound examination is one of the most important tasks for forensic pathologists and is indispensable to distinguish antemortem wounds from postmortem damage. For vital wounds, estimating the age of the wound is also essential in determining how the wound is associated with the cause of death. We investigated bone marrow-derived cells as promising markers and their potential usefulness in forensic applications. Although examination of a single marker cannot provide high reliability and objectivity in estimating wound age, evaluating the appearance combination of bone marrow-derived cells and the other markers may allow for a more objective and accurate estimation of wound age.

Electric or traumatic injury? The role of histopathological investigations

Analysis of wounds is crucial in forensic medicine to prove how an injury was caused. In many cases, microscopic analysis may be decisive. It is often difficult to distinguish macroscopic skin lesions resulting from electrical, mechanical and from thermal trauma where these occur simultaneously and to formulate a correct differential diagnosis. We report two cases in which the injuries found on the bodies and the manner of death raised uncertainty. An autopsy was performed. External examination of the bodies showed skin injuries that needed histopathological analysis to reconstruct the dynamics and the manner of death which has an important role in doubtful cases.

Characteristics of electrically injured skin from human hand tissue samples using Fourier transform infrared microspectroscopy

This technical note describes a method for distinguishing normal skin tissue samples from those electrically injured by Fourier transform infrared microspectroscopy (FTIR MSP). Furthermore, the infrared spectral features of electrically injured cells and tissues were evaluated to identify molecular changes in epidermal cells. In the present study, 20 human hand tissue samples were evaluated macroscopically and histopathologically. The electrically injured skin samples were subdivided into 2 regions [normal cell regions (NCRs) and polarized cell regions (PCRs)] and 14 major spectral absorption bands were selected. The spectral results showed that the band absorbance at 1080, 1126, 1172, 1242, 1307, 1403, 1456, 1541, 2852, 2925, 2957, 3075, and 3300cm(-1) increased significantly both in the stratum and non-stratum corneum of the PCRs in electrically injured skin tissues samples. No significant difference was found between normal skin and the NCR of the electrically injured skin samples. The band absorbance ratios of A1172/A1126, A1456/A1403, and A2925/A2957 were significantly increased, whereas the A1652/A1541 ratio was decreased in the PCR of the stratum corneum and non-stratum corneum. Baseline changes from 4000 to near 1737cm(-1) were observed in the spectra of the electrically injured skin samples, which were interpreted in terms of the pathological process involved in electrical injury. FTIR-MSP presents a useful method to provide objective spectral markers for the assisted diagnosis of electrical marks.

Histopathological differentiation of skin lesions caused by electrocution, flame burns and abrasion

The aim of this study was to reveal histopathological features for differential diagnosis of skin lesions caused by electrocution, flames and abrasions. Based on the causes of the lesions, cases were assigned into three groups. Group 1 included 30 deaths from electric shock. Group 2 included 30 individuals with flame burns who died in the fires. Group 3 included 30 deaths from traffic accidents, from which the individuals had abrasions. Data from the crime scene investigations and macroscopic and microscopic findings from the autopsies allowed determination of the cause of death in all cases. The features of the lesions examined under the light microscope were intraepidermal separation, subepidermal (dermoepidermal) separation, coagulation necrosis in the epidermis, nuclear elongation in the epidermis, dark-staining epidermal nucleus, depth of homogenization in the dermis, and nuclear elongation in the epithelium of hair follicles. A significantly high rate of electrical lesions had intraepidermal separation. The rate of subepidermal separation was slightly more significant in flame burns. A significantly higher rate of electrical lesions had both intraepidermal and subepidermal separation. The rate of coagulation necrosis in the epidermis was significantly the highest in electrical lesions. Although the severity of nuclear elongation was the most significant in electrical lesions, varying degrees of nuclear elongation in the epidermis were present in all three groups. Dark staining of the epidermal nuclei was present in all lesions except for one electrical lesion, though the severity of staining was significant in the abrasion group. The depth of homogenization was slightly more significant in the abrasion group. The rate of nuclear elongation in the epithelium of the hair follicles was significantly lower in the abrasion group. The results of this study revealed that certain morphological changes determined under a light microscope could help the differential diagnoses of electrical lesions, flame burns and abrasions.

Forensic application of VEGF expression to skin wound age determination

An immunohistochemical study combined with morphometry was carried out to examine the time-dependent expression of vascular endothelial growth factor (VEGF) using 53 human skin wounds with different wound ages (groups I: 0-12 h, II: 1-4 days, III: 7-14 days and IV: 17-21 days). In the human wound specimens aged 4-12 h, neutrophils recruited at the wound showed no positive signals for VEGF. With an increase in wound ages of > or =7 days, granulation tissue and angiogenesis were observed, with the migration of macrophages and fibroblasts of which the cytoplasm expressed VEGF-positive reactions. Morphometrically, the average VEGF-positive ratio was highest in group III, followed by that of group IV. In groups III and IV, 13 out of 26 wound samples had VEGF-positive ratios of more than 50%. However, all of the wound samples in groups I and II showed VEGF-positive ratios of less than 50%. With regard to the practical applicability and forensic validity, these observations suggest that a VEGF-positive ratio of more than 50% possibly indicates a wound age of 7 days or more.

Proliferative Activity of Epidermal Basal Cells after Wounding

Quantitative changes in nucleolus organizer regions (NORs) are known markers of proliferation that can be demonstrated by a specific silver staining technique on paraffin-embedded sections. Wounding of skin induces proliferation of basal epidermal cells at the wound margin. The degree of proliferation depends on the survival time and can be measured by morphometric assessment of argyrophilic NORs (AgNORs). Following incision wounding of the pinnae, rats were allowed to survive for different intervals (7 rats per interval) up to 120 hours. Before each sacrifice, biopsies were taken and incubated in a bromodeoxyuridine (BrdU) solution, embedded in paraffin, and stained with an antibody against BrdU. At the same time morphometric analysis of AgNOR counts was performed on sections made from the same material. BrdU incorporating nuclei were assessed by simple counting, whereas morphometric analysis of AgNOR counts was computer aided. Both methods revealed an increase in the number of proliferating cells, a plateau phase being reached after about 36 hours, followed by a decline after about 70 hours. Both methods thus allowed a reliable temporal classification of the skin injury according to survival time. The molecular background of the AgNOR changes in relation to the proliferation of cellular elements is discussed in detail.

Forensic wound examination

Wound examination is of prime importance in forensic pathology, and it is desirable to establish a wound examination system in order to evaluate and record the nature of wound more accurately and objectively. Modern diagnostic techniques and devices as well as advanced cell-biological methods should be introduced as the means for this aim. For example, radiological, endoscopic or magnetic resonance imaging (MRI) examination have been used in addition to examination with the naked eye. In our department, a binocular surgical operating microscope is routinely employed at forensic autopsy, which is useful for elucidating the nature of wound in more detail. It is also necessary to determine whether a wound has vitality, and, if antemortem, how long before death the wound has been sustained. For the determination of wound age including vitality, various biological factors such as cytokines and extracellular matrix components involved in wound healing have been examined by histopathological methods. Our studies have shown that interleukin (IL)-1alpha, IL-1 b, IL-6, IL-10 and tumor necrosis factor-alpha are possibly useful markers for wound age determination as well as cell-biological indicators of vitality. Furthermore, molecular biological techniques have been intended to be applied to wound examination; our experimental study has shown that even mRNA of cytokines mentioned above can be histologically detected by reverse transcriptase-polymerase chain reaction or in situ hybridization. A trial of forensic wound examination from macroscopic to molecular level is discussed.

Advances in the diagnosis of wound vitality: a review

The diagnosis of the vital origin of wounds in many cases remains an unsolved problem for the forensic pathologist. Practical experience enables the expert to diagnose the vital or postmortem origin of wounds on the basis of macroscopic examination. In some cases, optic microscopy is used to confirm the diagnosis. In many other cases, additional more sensitive and specific markers of vitality are required. In the past 50 years, comprehensive research on this topic has resulted in a better understanding of the acute inflammatory reaction. The development and application of sensitive and specific markers through research in the areas of histochemistry, enzymology, and biochemistry has provided a partial solution to the problems involved in wound vitality diagnosis. A review of this challenging area of forensic pathology, including an explanation of these methods and markers, is presented in this paper.

Forensic diagnosis of death from cold

To clarify the forensic diagnosis of hypothermia, the postmortem changes in the bodies of 211 cases of hypothermia (partly including death from diseases) encountered between January 1990 and January 1999 were studied as follows:i) The rectal temperature had been measured in 83 cases in which the time after death was known relatively clearly, and the rate of decrease in the rectal temperature per hour was evaluated. The rate of decrease in the rectal temperature was 2.3 +/- 1.2 degrees C, 2.7 +/- 1.5 degrees C and 3.6 +/- 1.9 degrees C per hour (mean +/- SD) when the ambient temperature was > or = 0 degrees C, 0 degrees C > to >-10 degrees C and -10 degrees C > or =, respectively. ii) The color of blood collected from the right and left hearts was different in 43 (33.6%) of the 128 cases of death from cold that underwent inquest and in 20 (87.0%) of the 23 cases that underwent forensic autopsy. This color difference was useful for the diagnosis of fatal hypothermia. iii) Gastric or duodenal submucosal bleeding (Wishnewski's spots) was noted in 10 (43.5%) of the 23 cases that underwent forensic autopsy. iv) Paradoxical undressing was observed in 35 (21.3%) of the 164 cases that underwent inquest.

RNA and DNA synthesis of epidermal basal cells after wounding. Comparison of vital and postmortem investigations

Incision wounds were made on both of the pinnae of each rat, and two biopsies from both the ears were taken for examination after different survival times of the wounds. Two biopsies were taken from each ear, four from each animal, two intravitally and two postmortem after 24 hours storage at 8 degrees C. One each of the intravital and one each of the postmortem biopsies were prepared and evaluated for quantification of RNA and DNA synthesis rate using an in vitro incorporation model with 3H-cytidine and bromodeoxyuridine (BrdU) as markers. The intravital specimens showed a significant increase in 3H-cytidine incorporation in the basal cell layer after survival times of 10 to 24 hours. No increase in the rate of RNA synthesis in the basal cell layer as a function of wound age was seen in postmortem specimens. In both intravital and postmortem biopsies the labelling indices after BrdU exposition increased significantly in the period from 32 to 60 hours post-injury. This suggest that DNA synthesis induced during life continues after death. Applied to forensic practice, these findings point to the possibility of determining the vitality of a wound in postmortem tissue. The RNA synthesis, obviously, precedes the DNA synthesis after mechanical trauma.

The dynamics of inflammatory cytokines in the healing process of mouse skin wound: a preliminary study for possible wound age determination

The dynamics of inflammatory cytokines such as interleukin-1 alpha (IL-1 alpha), interleukin-1 beta (IL-1 beta), interleukin-6 (IL-6) and tumor necrosis factor-alpha (TNF alpha) during the healing process of mouse skin wounds were examined using the enzyme-linked immunosorbent assay and immunostaining. The applicability of this examination for wound age estimation is discussed from the perspective of forensic pathology. After wound induction, mice were sacrificed at intervals ranging from 0 to 240 h. The levels of TNF alpha and IL-1 beta began to elevate rapidly after wounding and reached a peak at 3 h. The IL-1 alpha level reached a peak at 6 h, and IL-6 peaked at 12 h. An infiltration of numerous leukocytes, indicating acute inflammation, was observed at 3 and 6 h, and the main source of the cytokines was immunohistochemically identified as neutrophils. These results indicate that TNF alpha and IL-1 beta play an important role in the commencement of inflammation. "Rebound" of cytokine levels, i.e. a re-increase, was observed at 72 h after wounding. Histological examination of the 72-h-old wound showed migration of fibroblasts and the formation of new granulation tissues, indicating the proliferative stage of the wound healing process. These experimental findings indicate that these cytokines have a close relationship to wound remodeling as well as to inflammation. From the viewpoint of forensic pathology, it is considered that inflammatory cytokines may become one of the markers for wound age estimation, but further studies are needed, especially those involving the investigation using human wound specimens with known time intervals after injury.