Routine techniques in forensic neuropathology as demonstrated by gunshot injury to the head.

It will be vital to the practical activity of every forensic and/or clinical pathologist to be able to answer three questions regarding the reconstruction of a lethal event: the type and cause of death, as well as the survival time. The authors offer an overview of the application of selected morphological techniques in general forensic neuropathology, techniques that provide answers to some of the main questions in forensic neurotraumatology. The methods are illustrated by individual cases of lethal gunshot injury to the head from low velocity handguns. Besides the general forensic tasks of interpretation of the crime scene and postmortem external examination of the victim's body a computed tomography is recommended for documentation and reconstruction of the missile track. The microscopic techniques involve Nissl-stain for neurons, hematoxylin and eosin for delayed ischemic neuronal alterations, microtubule-associated protein (MAP) expression for acute neuronal ischemia, luxol-fast-blue-stain for myelin destruction (and demyelination), silver-stain for axons, beta-amyloid precursor protein (beta-APP) for axonal injury, glial fibrillary acidic protein (GFAP) for astrocytic characterization, naphthol AS-D-chloroacetate esterase for neutrophilic infiltration and CD68-expression for microglial reaction. The pattern of methods lead--in the case of gunshot injury as well as in any traumatic impact to the head--to answers according the extent of tissue destruction (and the cause of death), the biometric reconstruction of the criminal event, and the timing of (gunshot) wounds of the brain. These methods will be indispensable for the preparation of future neuropathological expert reports addressing questions of type of injury, the consequent pathological symptoms, timing of the injury, and the cause of death.

Pathomorphological staging of subdural hemorrhages: statistical analysis of posttraumatic histomorphological alterations.

We examined 10 histomorphological alterations of 222 cases of subdural hemorrhages following mechanical closed brain injury (MBI) to determine the posttraumatic interval (PTI). These morphological features included red blood cells (RBCs), polymorphonuclear leukocytes (PMNs), macrophages (Ms), RBC-containing Ms, hemosiderin-containing macrophages, hematoidin, fibroblasts, endothelial cells, collagenous fibers and membrane formation. The interval between the time of brain injury and death ranged from a few minutes to 33 years. Following routine staining and immunohistochemical staining of macrophages (CD68), paraffin sections were examined by light microscopy for the presence of the selected histomorphological features. An apparent correlation was found between the frequency of a given histomorphological phenomenon and the length of the PTI. Half of the cases (group 1; n=111) were used to develop a multistage evaluation system, the other half (group 2; n=111) to check its accuracy of prediction. Applying this multistage evaluation model and a special software, 85 of the 111 control group cases (76.6%) could be correctly classified and further 21 cases (18.9%) being assigned to an interval close to the correct interval. Therefore, classification of the correct PTI or an interval close to the correct PTI could be achieved in 95.5% of all cases.

Hypoxic-ischemic changes in SIDS brains as demonstrated by a reduction in MAP2-reactive neurons.

Sudden infant death syndrome (SIDS) is characterized by a lack of any known morphological or functional organ changes that could explain the lethal process. In the present study we investigated the hypothesis of an association between hypoxic/ischemic injury and SIDS deaths. In a previous study, we could demonstrate by quantitative immunohistochemistry a distinct drop in microtubule-associated protein (MAP2) reactivity in neurons of adult, human brains secondary to acute hypoxic-ischemic injuries. Here we applied the same method on sections of the frontal cortex and hippocampus of 41 brains of infants younger than 1 year of age. For each brain area 100 selected neurons were evaluated for their MAP2 reactivity in the different layers of the frontal cortex and in the different segments of the hippocampus. Three groups were compared: (1) SIDS victims (n = 17), (2) infants with hypoxia/ischemia (control group one; n = 14), (3) infants without hypoxic/ischemic injury (control group two; n = 10). The SIDS group and hypoxic/ischemic group exhibited a general reduction in the number of MAP2 reactive neurons in comparison with the non-hypoxic/ischemic injury group. The SIDS group also had a significantly lower (P < 0.05) number of reactive neurons in the CA2 and CA3 areas of the hippocampus than did control group two. No difference was detected between the SIDS group and control group one. The SIDS brains were thus found to display hypoxic/ischemic features without however providing evidence as to the cause of the oxygen reduction.

The 4977 bp deletion of mitochondrial DNA in human skeletal muscle, heart and different areas of the brain: a useful biomarker or more?

It has been suggested that deletions of mitochondrial DNA (mtDNA) are important players with regard to the ageing process. Since the early 1990s, the 4977 bp deletion has been studied in various tissues, especially in postmitotic tissues with high energy demand. Unfortunately, some of these studies included less than 10 subjects, so the aim of our study was to quantify reliably the deletion amount in nine different regions of human brain, heart and skeletal muscle in a cohort of 92 individuals. The basal ganglia contain the highest deletion amounts with values up to 2.93% and differences in deletion levels between early adolescence and older ages were up to three orders of magnitude. Values in frontal lobe were on average an order of magnitude lower, but lowest in cerebellar tissue where the amount was on average only 5 x 10(-3) of the basal ganglia. The deletion started to accumulate in iliopsoas muscle early in the fourth decade of life with values between 0.00019% and 0.0035% and was highest in a 102-year-old woman with 0.14%. In comparison to skeletal muscle, the overall abundance in heart muscle of the left ventricle was only one-third. The best linear logarithmic correlation between amount of the deletion and age was found in substantia nigra with r=0.87 (p<0.0005) followed by anterior wall of the left ventricle (r=0.82; p<0.0005). With regard to mitochondrial DNA damage, we propose to use the 4977 bp deletion as an ideal biomarker to discriminate between physiological ageing and accelerated ageing. The biological meaning of mitochondrial deletions in the process of ageing is under discussion, but there is experimental evidence that large-scale deletions impair the oxidative phosphorylation in single cells and sensitize these cells to undergo apoptosis.

Shaken baby syndrome: re-examination of diffuse axonal injury as cause of death.

The discussion surrounding shaken baby syndrome (SBS) arose from the lack of evidence implicating diffuse axonal injury (DAI) as a cause of death. It was assumed instead that injury to the cervical cord, medulla, and nerve roots played a causal role. The present pathomorphological study examines 18 selected infants (<1-year-old) whose deaths were highly suspicious for SBS, exhibiting the classical SBS triad of acute subdural hemorrhage (SDH), retinal bleeding, and encephalopathy. Gross autopsy and microscopic findings of these infants were compared with those of 19 victims of sudden infant death syndrome (SIDS; control group 1) and of 14 infants who died of disease or injuries/violence not involving the head, neck or eyes (control group 2). Symptoms of mechanical impact to the head were evident in seven of the SBS infants, but in none of the control infants. DAI was not detected in either the SBS or control cases. Localized axonal injury (AI) was regularly present in the brains of the SBS infants surviving longer than 1.5-3.0 h, but only occasionally in the craniocervical junction and within the nerve roots of the upper cervical cord; it was never present in the medulla. Epidural hemorrhage of the cervical cord was seen in four of the ten examined SBS cases, but in none of the control cases. Based on the absence of DAI in the brain and of signs of generalized cervical cord or nerve root injuries, we conclude that the cause of death in the SBS victims was a global cerebral ischemia secondary to SDH, focal vasospasm, trauma-induced transitory respiratory and/or circulatory failure.

Near-drowning and clinical laboratory changes.

Opposite to clinical laboratory findings in experimental drowning of animals (erythrocytic lysis, hyperkalemia, and final cardial fibrillation) are the observations in drowned humans (increase of pCO2, hypoxic encephalopathy), which leads to a different pathophysiological interpretation of the drowning process. This process, however, is recently discussed again, therefore an additional study seemed to be recommended. In a retrospective study, 31 cases of near-drowning (23 cases: fresh water; 8 cases: brackish water) clinical laboratory data were analysed. While 21 of the cases were fatal with a delay of up to 180 days, 10 individuals survived the accident, four cases with severe neurological deficits. Data of pH, potassium, sodium, chloride, hemoglobin and total protein were collected during the very early post-drowning period. Nearly all cases (96%) revealed a reduction of pH due to hypoxic acidosis, and only two cases (6.5%) exhibited a slight hyperkalemia. The hemoglobin level was normal in most of the cases (83%) and slightly reduced in the others (17%) while the protein level was slightly reduced in most of the fatalities (80%). As a result of our investigation we have to state the lack of hyperkalemia as well as of an increase of the hemoglobin level indicate that there is no distinct intravascular red cell lysis due to influx of water into the vascular compartment. Therefore the death by drowning in humans in most cases is the result of a hypoxic cerebral process. A comparison with animal experiments obviously is not helpful because the drowning process in humans leads to an aspiration of only 2-4 ml water/kg, while in animal experiments more than 10 ml water/kg will be artificially aspirated leading to red cell lysis as well as to electrolyte disturbances and cardial fibrillation.

[Significance of additional RFLP single locus probes analysis after STR based determination of sibship]. / Die Aussagekraft zusäitzlicher RFLP-analysen bei Abstammungsbegutachtung mittels STR-Analyse.

Autosomal STR typing alone seems to be no sufficient tool for resolving deficiency cases (e.g. cases of questioned paternity or half-sibships). Therefore, we investigated whether the additional analysis of RFLP single locus probes can improve the solution of such complicated kinship cases. We analyzed 207 children and men from 101 families using the AmpFlSTRIdentifiler multiplex PCR kit and three RFLP single locus probes. A comparison between each child and all unrelated men resulted in 11,023 man / child pairs. Less than three excluding STRs were found in 125 child / unrelated man pairs (1.13%). Additional analysis of RFLP results reduced the number of ambiguous cases to 35. Half-sibling pairs were simulated using STR results from 20 cases with high paternity probabilities (group 1) and relatively low paternity probabilities (group 2). Using a commercially available computer program we calculated probabilities for 778 half-sibling pairs. In 35 pairs (4.49%) half-sibling probabilities over 90.0% could be calculated. Additional investigation of RFLP single locus probes did not lead to a more reliable evaluation of these results. The combined investigation of autosomal STRs and RFLP single locus probes can satisfactorily solve deficient paternities but does not contribute to the solution of questioned half-sibships.

Cellular localization of pituitary adenylate cyclase-activating peptide (PACAP) following traumatic brain injury in humans.

The pituitary adenylate cyclase-activating peptide (PACAP) is involved in many processes of the developing and mature central nervous system, such as proliferation, differentiation, apoptosis, neurotransmission, inflammation and neuroprotection. Alternative posttranslational processing of PACAP results in two biologically active, amidated 27- and 38-amino acid peptides termed PACAP27 and PACAP38. In the present study, we examined whether traumatic brain injury (TBI) affects cellular immunopositivity for PACAP27 and PACAP38. Patients (n = 55) were classified into three groups dependent on their survival time (under 24 h, between 24 h and 7 days and between 7 days and 99 days postinjury). PACAP27 and PACAP38 were expressed by neurons and glial cells in normal human neocortex (n = 10). Following TBI, the total number of PACAP27- and PACAP38-positive cells was significantly decreased for a prolonged survival period within the traumatized neocortex. In the pericontusional cortex, the number of cells expressing PACAP27 and PACAP38 was significantly increased at all survival times examined. Triple immunofluorescence examinations revealed a significant increase in the absolute numbers of GFAP-positive reactive astrocytes as well as a decrease in the CNP-positive oligodendrocytes, each coexpressing PACAP27 or PACAP38 in the contusional and pericontusional cortex. We hypothesize that the increase of glial PACAP immunoreactivity may be interpreted as part of a complex endogenous neuroprotective response in the pericontusional regions, but the precise role of PACAP following TBI is yet to be determined.

Decreased expression of glutamate transporters in astrocytes after human traumatic brain injury.

The primary mechanism for eliminating synaptically released glutamate is uptake by astrocytes. In the present study, we examined whether traumatic brain injury (TBI) affects the cellular expression of glutamate transporters EAAT1 and EAAT2. Morphometrical immunohistochemical analysis demonstrated a predominant expression of EAAT1 and EAAT2 in astrocytes of normal human neocortex (n = 10). Following traumatic injury of human brain (n = 55), the number of EAAT2-positive cells was decreased for a prolonged survival period within the traumatized neocortex and the pericontusional region. GFAP-positive astrocytes decreased in number within the first 24 h. Thereafter, the number of GFAP-positive astrocytes increased again, indicating formation of reactive gliosis. Double immunofluorescence examinations revealed a reduction in absolute numbers of GFAP-positive astrocytes coexpressing EAAT1 or EAAT2 at survival times up to 7 days. In addition, the relative fractions of astrocytes coexpressing glutamate transporters decreased following TBI. We conclude that the posttraumatic reduction in cellular EAAT 1 and EAAT2 expression is predominantly due to degeneration of astrocytes and to downregulation in surviving astrocytes. Our results support the view that reduced glutamate uptake by astrocytes contributes to posttraumatic elevation of extracellular glutamate in humans.

Tissue-specific deletion patterns of the mitochondrial genome with advancing age.

Aging is a multifactorial process and a lot of theories have been put forward to explain the deterioration of organ function with advancing age. The free radical hypothesis developed by Harman is amongst the most prominent today and has been focused on mitochondrial aging in the last decades. Applying a long PCR approach we screened human skeletal muscle, heart, caudate nucleus and cerebellum of 50 individuals for large-scale deletions of mitochondrial DNA (mtDNA). The most important observation of our study was the detection of age dependent tissue specific deletion patterns of mtDNA. The pattern of the same tissue of different individuals was more similar than the pattern of different tissues of the same individuals. Whereas deletions were barely detectable in cerebellar tissue, in caudate nucleus a specific banding pattern with deletions of 4-8 kb was already observed around the age of thirty. However, the increase of these large-scale deletions in number and variety over lifetime was more pronounced in skeletal muscle or heart. Our data support the notion that different tissues accumulate mtDNA damage in a specific manner. Although functional consequences of mitochondrial deletions are clearly supported by experimental data on the single-cell level in model organisms and mammals, their role regarding impaired function of organs with advancing age in humans remains unresolved.

The problem of single parent/child paternity analysis--practical results involving 336 children and 348 unrelated men.

In a certain amount of paternity investigations, only DNA from child and alleged father is analyzed, thus increasing the possibility of false paternity inclusions. The aim of this study was to determine how many wrong paternity inclusions could be detected in a rather small geographical area comparing empirical results from 336 children and 348 men (13-15 STRs were investigated per person). This comparison between each child and all unrelated men (i.e. all putative fathers from the other cases) with an especially designed computer program resulted in 116,004 man/child pairs. Less than three excluding STRs were found in 1666 child/unrelated man pairs (1.44% of the comparisons). At least one unrelated man with only two or less STR mismatches could be determined for 322 children (95.8% of all investigated children). In 26 comparisons no STR mismatches between a child and an unrelated man were detected, thus at least one and up to three "second father(s)" under 350 men could be found for 23 children, if the mother is excluded. Paternity probabilities between 95.475% and 99.996% were calculated. Our results underline the difficulties in motherless paternity cases using only STR analysis and advise great precaution in assigning verbal predicates such as "paternity proven" in those investigations.

Microtubule-associated protein 2 (MAP2)--a promising approach to diagnosis of forensic types of hypoxia-ischemia.

The loss of neuronal immunoreactivity of the cytoskeletal microtubule-associated protein 2 (MAP2) is known to be a marker of--at least--transient functional failure of neurons following ischemia. Because there are no specific neuropathological findings in forensic types of acute hypoxia-ischemia, detection of this relevant cause of death is often complicated and a reliable ischemic biomarker would be of great importance. We therefore investigated the neuronal immunoreactivity of MAP2 in human cases of forensic significance. A control group (n=27) was compared to a group of cases of hypoxia-ischemia (n=45), comprising death due to hanging (n=19), drowning (n=14) and carbon monoxide (CO) poisoning (n=12). Using immunohistochemical staining, the percentage of MAP2-positive neurons in the hippocampus (areas CA1-CA4) and frontal cortex (layers II-VI) was evaluated and compared. The hypoxia-ischemia group showed decreased MAP2 immunostaining in the hippocampal areas CA2-CA4 (P<0.05) and in cortical layers II-VI (P<0.001) compared to controls. Most vulnerable regions seem to be the hippocampal CA4 area and cortical layers III-V. Within the hypoxia-ischemia group, death due to CO poisoning was characterized by the lowest MAP2 immunoreactivity. The hypoxic-ischemic groups differ from controls by a distinct decrease of MAP2 immunostaining. Thus, the loss of MAP2 immunoreactivity may support the diagnosis of neuronal injury in forensic types of hypoxia-ischemia, although investigations on postmortem tissue must be interpreted cautiously.

Lack of age-related increase of mitochondrial DNA amount in brain, skeletal muscle and human heart.

During the ageing process, an increase of mitochondrial DNA (mtDNA) deletions and other mutations have been reported. These structural alterations of mtDNA are assumed to cause a reduction in the respiratory chain activity and may contribute to the ageing process. Therefore, the question arises if the accumulation of deleted mtDNA is compensated in vivo by an increase of mtDNA synthesis via a feedback mechanism. We designed two human mtDNA-specific oligonucleotide probes for quantitative mtDNA analysis of 5 different tissues from 50 individuals aged from 8 weeks to 93 years. The amount of mtDNA was approximately 1.1 +/- 0.5% (4617 +/- 2099 copies) in the caudate nucleus, 1.0 +/- 0.5% (4198 +/- 2099 copies) in the frontal lobe cortex, 0.3 +/- 0.2% (1259 +/- 840 copies) in the cerebellar cortex, 1.0 +/- 0.4% (4198 +/- 1679 copies) in skeletal muscle and 2.2+/-1.3% (9235 +/- 5457 copies) in heart muscle. We did not observe any significant change in the absolute copy number during ageing in five different tissues, and therefore, found no evidence for the postulated feedback mechanism. Our study indicates that mtDNA copy number is tissue-specific and depends on the energy demand of the tissue.

A simple Duplex-PCR to evaluate the DNA quality of anthropological and forensic samples prior short tandem repeat typing.

Typing of DNA from ancient or otherwise highly degraded material, e.g. formalin fixed tissues, can be difficult, time consuming and costly. Very often, genetic typing is not possible at all. We present an inexpensive and easy to use Duplex-PCR that amplifies a 164 bp fragment specific for nuclear DNA together with a 260 bp mitochondrial DNA fragment and that can be employed as a pretest prior to short tandem repeat (STR) typing. All together, we analyzed DNA from 20 ancient bones, 20 formalin fixed tissues and 20 other forensic samples in different concentrations. Each sample that failed in the presented Duplex-amplification was also negative for STR typing, while samples that showed strong and clear signals in the Duplex-PCR led to reproducible genetic profiles using the multiplex kits AmpFLSTR Identifiler and Powerplex ES. The Duplex-PCR worked as a reliable indicator of DNA quality in the sample.

The use of different multiplex PCRs for twin zygosity determination and its application in forensic trace analysis.

STR typing becomes more and more valuable for different approaches of science. It revolutionized determining of zygosity in twin research and it is very often the only possibility for discrimination in forensic trace analysis. In this study 55 twin pairs from Denmark were genetically investigated to determine their zygosity. For analysis two multiplex PCR kits, the AmpFlSTR Identifiler kit, which comprises 15 loci plus the amelogenin gender determination and the Powerplex ES kit with eight different loci were employed. For a forensic approach every twin pair was regarded as being a forensic trace analysis, i.e. suspect or victim/biological trace and then we determined the security and precision with that a match of genetic patterns or an exclusion could be observed. Sixty percent of the twin pairs were di- and 40% monozygotic. There were no differences in zygosity determination between the two multiplex kits. The lowest number of exclusions by determining dizygosity was four loci for the Identifiler and three for Powerplex ES kit, the highest was 13 (Identifiler) and eight (Powerplex). It could be shown that the highly discriminative multiplex PCR kits gave matching probabilities of over 99.999999% (calculation based on data for unrelated individuals) even when only five or six STRs could be determined (assuming a trace analysis with some non-detectable STRs and therefore an incomplete genetic pattern). No questionable results regarding zygosity of the twin pairs were obtained even when only eight loci (using the Powerplex ES kit) were investigated. The simulated forensic results showed that matching probabilities should always be handled with care to not possibly come to wrong conclusions concerning the origin of the biological trace.

[Degradation of biomolecules: a comparative study of diagenesis of DNA and proteins in human bone tissue]. / Degradation von Biomolekülen: Eine vergleichende Studie zur Diagenese von DNA und Proteinen in humanem Knochengewebe.

Diagenesis of macromolecules is a not yet fully understood process that can be important for anthropological and forensic research. Trying to elucidate the diagenesis of DNA and proteins we investigated the process of fragmentation of DNA and razemisation of aspartic acid in human bone material. We created an in vitro-model of accelerated aging by incubating bone samples in hot water. A comparison of diagenesis of molecules in those artificially aged samples with altogether 30 historical bones from different regions and of different ages was carried out. The in vitro-model showed the expected positive correlation between the increase of razemisation of aspartic acid and DNA fragmentation, while there was a much lesser correlation when investigating historical bones. The in vitro-model showed the expected correlation between the increase of razemisation of aspartic acid and DNA fragmentation and to a much lesser extent in historical bones. This study shows that diagenesis is probably influenced by additional forces affecting different macromolecules in different ways.

[Paternity analysis in deficiency cases with related putative fathers: simulation of a deficiency analysis in 27 families]. / Abstammungsbegutachtungen in Defizienzfällen mit verwandten Putativvätern: eine simulierte Analyse in 27 Familien.

During the last few years, the number of privately ordered paternity investigations has increased considerably. Probably due to financial reasons in more and more cases only the putative father and the child are investigated. Additionally, very often only one method, such as STR analysis, is employed. This raises the question whether such a reduced analysis leads to reliable and clear results when investigating cases with related putative fathers. We investigated 165 individuals from 27 families using the AmpFlSTRIdentifiler multiplex PCR and calculated the paternity probabilities of the children to their biological fathers, uncles, grand fathers and other relatives. In more than 30% less than three exclusions between child and relative were detected. In five cases no exclusions were found between child and uncle, always leading to paternity probabilities >99.9%. These results show that the calculation of high probabilities (>99.9%) does not necessarily lead to the accurate conclusion of fatherhood. In many of our cases misleadingly the brother of the real father or another close relative would have been declared to be the biological father.

Methodical approach to brain hypoxia/ischemia as a fundamental problem in forensic neuropathology.

A review is given summarizing different methods that have been applied to the specific forensic neuropathological question of brain hypoxia/ischemia. On the microscopic level the authors applied routine stains and immunohistochemistry (MAP2, ALZ 50, GFAP, CD68, beta-APP) for characterization of the functional activity of neurons as well as of different cell types in various brain areas. Moreover, using molecular techniques for evaluation of the mitochondrial 4977-bp deletion in correlation to hypoxia and to age brain tissue and single cell analyses are described. The demonstrated scope of methods and results give evidence of the wide spectrum of possibilities to visualize hypoxic brain injuries for determining the cause (and matter) of death and for reconstructing the time-dependent process.

Active euthanasia and physician-assisted suicide: the German discussion.

The debate on legalization of active euthanasia in the Netherlands and Belgium and the refused legal right to choose the circumstances of Diana Pretty's own death are the last actual reasons for reconsidering the situation in Germany. Around the world heated debates have broken out on the topic of active euthanasia. Specialists in the field of 'forensic medicine' have taken full part in these discussions. The present survey from the point of view of forensic medicine begins with a look at current terminology and at the laws pertaining to euthanasia in Germany. These laws are then contrasted with actual practice, including a description of the increasing acceptance of active euthanasia by the German population. The main argument against legalization of active euthanasia is that its formal acceptance in law would cause the dam of restraint to burst, culminating in widespread misuse, as already seen in recent serial killings by nurses in hospitals and homes for the elderly around the world. Contrasted with this are the arguments for taking active steps at the end of life, including emotional considerations such as the revulsion against mechanized medicine and the fear of pain and rational arguments such as the necessity to end a 'life unworthy of life', to save medical costs, and obtaining prior consent in 'living wills'. Such considerations have put in jeopardy the moral integrity of the medical profession - and thus the layperson's trust in physicians--around the world. In Germany especially the history of mass killing during the Nazi era constitutes a fundamental argument against active euthanasia. As a consequence, in Germany active euthanasia will not receive legal sanction, although recommendations on rendering dying more bearable are permitted.

Extraction and amplification of nuclear and mitochondrial DNA from ancient and artificially aged bones.

An experimental design is presented that simulates an accelerated process of DNA degradation in human bone tissues and thus provides a possibility for a systematic investigation of factors hampering DNA extraction and amplification. Equal sized slices of human femoral bones were incubated in 90 degrees C water for 2 h up to 30 days. DNA was extracted and subjected to a human specific Duplex polymerase chain reaction (PCR) and also to a Multiplex short tandem repeat (STR) PCR. Additionally 24 ancient bones representing different age periods were investigated in the same way. The results were compared to those from the artificially aged samples. After just 12 h of incubation, DNA is totally degraded, but still fully typable. After 36 h no reproducible amplification of DNA is possible. Using Multiplex PCR the DNA from artificially aged bones shows the typical STR pattern for ancient samples suggesting that the in vitro approach provides a useful and comparable method to elucidate the DNA degradation process in bones.