![]() Additionally, the necessary steps to be taken before calculating the discriminating values between "normal" and "diseased" are described. The conceptual problems of reference values in vitreous humor as a mirror of blood are addressed. However, using another fluid compartment as a mirror of blood at the moment of death involves severe methodical problems. Due to the rapid postmortem breakdown of metabolism and active membrane transport only analytes which are stable in blood can be determined on this fluid compartment, other parameters have to be analysed on other fluid compartments like vitreous humor (VH). Postmortem biochemistry may provide significant information in determining the cause of death. These observations suggested the stability of UN, Cr and UA in the pericardial fluid within 48 h postmortem and their usefulness for the pathophysiological investigation of death involving azotemia. Although the pericardial levels were otherwise similar to the clinical serum reference ranges, only the drowning fatalities showed significantly lower levels for each marker. These postmortem findings showed azotemia due to renal failure, elevated protein catabolism and rhabdomyolysis. There was a significant elevation in the three markers for chronic renal failure, gastrointestinal bleeding, hyperthermia, hypothermia, methamphetamine fatalities and delayed traumatic death, which was comparable with the clinical criteria for their serum levels. The aim of the present study was to examine postmortem pericardial fluid for urea nitrogen (UN), creatinine (Cr) and uric acid (UA) levels to investigate the pathophysiology of death in forensic autopsy cases (total, n = 409 within 48 h postmortem), which included blunt, sharp instrument injury, asphyxiation, drowning, fire fatalities, hyperthermia, hypothermia, methamphetamine-related fatalities, other poisoning, delayed death from trauma and natural diseases. In postmortem biochemistry, there is insufficient data available for the practical analysis of factors in the pericardial fluid. This is the first systematic study of multiple metabolic changes post-mortem and demonstrates the nature and extent of the changes that occur, in addition to identifying potential markers for estimating post-mortem interval. The concentration of lactate increased and then remained at an elevated level and changes in the concentration were different in the rat compared to the human and pig. Concentrations of hypoxanthine, ammonia, NADH and formic acid all increased with time and these metabolites may be potential markers for post-mortem interval. Blood pH in corpses fell from 7.4 to 5.1. The pH and the concentration of all six metabolites changed post-mortem but the extent and rate of change varied. In this study blood pH and changes in concentration of six metabolites (lactic acid, hypoxanthine, uric acid, ammonia, NADH and formic acid) were examined post-mortem over a 96 hour period in blood taken from animal corpses (rat and pig) and blood from rats and humans stored in vitro. These biochemical changes may provide chemical markers for helping to more accurately determine the time since death (post-mortem interval), which is challenging to establish with current observation-based methodologies. Post-mortem blood should be sampled as soon as possible, as increased post-mortem intervals may heavily change marker levels in-situ in individual cases, whereas the markers are mostly unaffected by laboratory conditions.ĭeath is likely to result in very extensive biochemical changes in all body tissues due to lack of circulating oxygen, altered enzymatic reactions, cellular degradation, and cessation of anabolic production of metabolites. Potential contamination of arteriovenous blood did not influence the post-mortem marker levels. Furthermore, the markers were robust enough to withstand freeze-thaw cycles. ![]() Marker levels showed high intra-assay precision. Excessive increases were observed for cardiac and muscle markers. Significant marker level changes began two hours after death. For all markers, we observed increasing marker levels for longer post-mortem intervals. Serum creatinine, urea, 3-β-hydroxybutyrate, tryptase, myoglobin, troponin T, creatin kinase and creatin kinase-MB have been included. In 20 cases, peripheral venous samples were taken starting immediately after circulatory arrest and ending 48 hours after death. The aim of the study was to determine the post-mortem stability of commonly-used serum markers at predefined time points. ![]() Such laboratory analyses are especially necessary in the cases of functional deaths without morphological evidence of the death causes and also in cardiac death cases with only very short survival times. Post-mortem biochemistry of serum markers has been the subject of numerous studies, but in-situ marker stability after death has not been sufficiently evaluated yet. ![]()
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