Rapid determination of carboxyhemoglobin in blood by Oximeter

Different methods to determine carboxyhemoglobin (COHb) in blood are described in the literature. In our laboratory three methods to analyze COHb in post-mortem blood samples were compared: the spectrophotometric method of Maehly, a gas chromatographic method with a thermal conductivity detector (GC-TCD) and the Oximeter. Several COHb containing blood samples of deceased persons were analyzed. Results of all three methods were comparable for low concentrations (ca. 10% COHb) as well as for high concentrations (ca. 80% COHb) regardless of the viscosity of the blood samples. The advantages of the Oximeter when compared to Maehly's method and GC-TCD are extreme short time of analysis (<1min), very small blood volume required (<0.1ml) and easy handling. In our opinion application of the Oximeter is not limited to analyses of blood samples from living persons (e.g. in clinical toxicology); it can as well be used for the determination of COHb in post-mortem blood samples. Hence it is a useful and time saving tool in forensic toxicology.     

Biostatistical basis of individualization and segregation analysis using the multilocus DNA probe MZ 1.3: results of a collaborative study.

A collaborative study using the multilocus minisatellite DNA probe MZ 1.3 was carried out to investigate segregation information, mutation rate, DNA fragment frequencies as well as band sharing characteristics. The fingerprint patterns of 393 children as well as 694 unrelated individuals were analysed after digestion of DNA with the restriction enzyme HinfI. A mutation rate of 1% per meiosis or 0.04% per band was found with a mean number of 26 bands/individual. It was shown that maternal and paternal fragments are inherited in equal proportions. Population frequencies of restriction fragments demonstrated a distribution with increasing frequencies in the small fragment size range below 10 kb as well as the absence of very common or very rare fragments. Our data can be used to calculate simple exclusion probabilities based on the number of non-maternal bands in the child.     

Identification of skulls by video superimposition

A method of matching skulls with photographic portraits or impressions of the face in clay by video superimposition is described. Two different practical cases are presented. The first one deals with the identification of a skull of a six-year-old girl, the second with the identification of the skull of the famous Swiss Pedagogue Johann Heinrich Pestalozzi, who died about 160 years ago. The advantages and versatility of this method are shown; also the setup of the equipment and the working technique.     

Suicide by severing blood vessels using local anesthesia: reduced risk in extraction of HIV infected tissue using a stomacher

Authors report an unusual suicide undertaken by a medical person who after applying the local anesthetic lidocaine, opened a leg vein with a scalpel. The cause of the suicide was presumed advanced AIDS symptoms with a progressive Kaposi sarcoma and Non-Hodgkin lymphoma. For the toxicological investigation of the tissue we used the stomacher extraction system, a method not widely known in Forensic science, however, recommended for the extraction of all infectious tissues.     

Beta-hydroxybutyric acid--an indicator for an alcoholic ketoacidosis as cause of death in deceased alcohol abusers

We analyzed the postmortem blood of a total of 100 fatal cases for beta-hydroxybutyric acid (BHBA). In 25 cases of sudden and unexpected death of alcoholics we found pathologically increased levels of BHBA of 1260 to 47200 (median 8000) micromol/L. This led us to the diagnosis of an alcoholic ketoacidosis (AKA) as cause of death in these cases. The control group of 69 postmortem cases revealed that BHBA concentrations below 500 can be regarded as normal, and values up to 2500 micromol/L as elevated. Our study shows that BHBA values over 2500 micromol/L could lead to death, if no medical attention is sought. During storage we did not find any indication of postmortem formation or decomposition of BHBA in blood in vitro or in the corpses. In our opinion, BHBA should be considered the diagnostic marker of choice for the postmortem determination of alcoholic ketoacidosis (AKA) as the cause of death. The classical indications of such deaths are: unexpected death of a chronic alcoholic; none or only traces of ethanol in the blood; increased acetone blood concentration; and neither autopsy, histology, microbiology, nor toxicology reveal the cause of death. In six further cases a diabetic ketoacidosis (DKA) was diagnosed as the cause of death.