[Cause of Death: 'Intoxication' - a Matter of the Concentration?]

Cause of Death: 'Intoxication' - a Matter of the Concentration? Abstract. Elucidation of the cause of death is one of the main reasons for medico-legal investigations. In clinical toxicology, the severity of a given poisoning is typically assessed with the blood concentration of a pharmacologically or toxicologically active compound. Such an interpretation proves to be difficult or even impossible in postmortem toxicology. Numerous biochemical and biological processes beginning immediately after death may render the calculated drug concentration unreliable. Concentrations obtained from postmortem samples do not necessarily reflect the blood concentration at the time of death. A prediction if and to what extent such postmortem changes might have occurred is still impossible for individual cases. Interpretation therefore needs to be done with care, considering case circumstances and all available information.

Preanalytic aspects in postmortem toxicology

The preanalytic phase has been recognized to have a substantial role for the quality and reliability of analytical results, which very much depend on the type and quality of specimens provided. There are several unique challenges to select and collect specimens for postmortem toxicology investigation. Postmortem specimens may be numerous, and sample quality may be quite variable. An overview is given on specimens routinely collected as well as on alternative specimens that may provide additional information on the route of administration, a long term or a recent use/exposure to a drug or poison. Autolytic and putrefactive changes limit the selection and utility of specimens. Some data from case reports as well as experimental investigations on drug degradation and/or formation during putrefaction are discussed. Diffusion processes as well as postmortem degradation or formation may influence ethanol concentration in autopsy specimens. Formalin fixation of specimens or embalmment of the corpse may cause considerable changes of initial drug levels. These changes are due to alterations of the biological matrix as well as to dilution of a sample, release or degradation of the drug or poison. Most important seems a conversion of desmethyl metabolites to the parent drug. Some general requirements for postmortem sampling are given based on references about specimen collection issues, for a harmonized protocol for sampling in suspected poisonings or drug-related deaths does not exist. The advantages and disadvantages of specimen preservation are shortly discussed. Storage stability is another important issue to be considered. Instability can either derive from physical, chemical or metabolic processes. The knowledge on degradation mechanisms may enable the forensic toxicologist to target the right substance, which may be a major break down product in the investigation of highly labile compounds. Although it is impossible to eliminate all interfering factors or influences occurring during the preanalytic phase, their consideration should facilitate the assessment of sample quality and the analytical result obtained from that sample.

Effect of post-mortem changes on peripheral and central whole blood and tissue clozapine and norclozapine concentrations in the domestic pig (Sus scrofa)

Interpretation of the results of psychoactive or other drug measurements in post-mortem blood specimens may not be straightforward, in part because analyte concentrations in blood may change after death. There is also the issue of comparability of plasma (or serum) results to those obtained in whole blood. To investigate these problems with respect to clozapine, this drug (10mg/kg daily) was given orally to two pigs. Blood was collected 3h post-dose on day 7, the animals were sacrificed, and blood taken from central and peripheral veins for up to 48 h after death. Tissue samples were also collected immediately after death and at 48 h. Ante-mortem whole blood clozapine/N-desmethylclozapine (norclozapine) concentrations were 0.86/1.07 and 1.11/1.15 mg/l in pigs 1 and 2, respectively. Blood clozapine and norclozapine concentrations generally increased after death (central vein: clozapine up to 300%, norclozapine up to 460%; peripheral vein: clozapine up to 155%, norclozapine up to 185%). Initial blood and kidney clozapine and norclozapine concentrations were comparable in both animals, but were some two-fold higher in heart, liver and striated muscle in pig 2. In both animals, the heart and striated muscle clozapine and norclozapine concentrations had increased some two- to three-fold at 48 h, whilst the liver and kidney concentrations were essentially unchanged. The reason for the increase in heart and striated muscle concentrations at 48 h is unclear, but could be simple variation in sample site. The plasma:whole blood distribution of clozapine and norclozapine was studied in vitro. In human blood (one volunteer donor, haematocrit 0.50) the plots of plasma versus whole blood concentration were linear for both analytes across the range 0.1-1.5mg/l, although clozapine favoured plasma (plasma:whole blood ratio=1.12), whereas norclozapine favoured whole blood (ratio 0.68). In pig blood, the plots of plasma versus whole blood were non-linear in both cases, although clozapine favoured plasma to a greater extent than norclozapine. This may be due to lower plasma clozapine and norclozapine protein binding capacity in the pig as compared to man.

Medicolegal anthropology in France

Medicolegal anthropology has a very long history in France. Basic studies on human skeletal remains started as early as the 18th century. The 19th century produced many medical theses and research papers on age, sex, as well as stature estimation. The research proliferated in the first 60 years of the 20th century, much of which is still in use in France and abroad. The later half of the 20th century, however, was dormant in research on human skeletal biology at a time when forensic anthropology was becoming an active field worldwide. In the last decade, medicolegal anthropology took a different perspective, independent of its traditional roots. Research and practice have both been in the professional domain of forensic physicians unlike the situation in many other countries. Population based studies requiring large databases or skeletal collections have diminished considerably. Thus, most research has been on factors of individualization such as trauma, time since death, crime scene investigation, and facial reconstruction. It is suggested that there is a need for cooperation between the forensic physician and anthropologist to further research. This also encourages anthropologists to carry out research and practice that can fulfill the needs of the medicolegal system of the country.