Immunostaining by complement C9: a tool for early diagnosis of myocardial infarction and application in forensic medicine

Before the first 12 hours, diagnosis of early myocardial infarctions is always difficult for forensic pathologists. We tested complement C9 expression in 121 formalin-fixed and paraffin-embedded heart samples by an immunohistochemical procedure. The heart specimens were separated into four groups: 33 cases in group 1 with typical ischemic damages histologically located, 20 cases in group 2 with death related to myocardial infarction on the basis of ischemic presentation on electrocardiogram but no obvious histological ischemic damage, 35 cases in group 3 with severe coronary disease without cause of death found at the autopsy, and 33 cases in group 4 without sign of myocardial infarction and without coronary disease. In the first group, all 33 heart samples showed a well-defined C9 expression in the necrotic areas. The second group in 17 of 20 cases showed positive areas for C9 expression. In the other three heart specimens, only few stained cells were observed whereas the painful symptoms had begun less than 1 h before death. The third group showed C9 immunopositive areas in six of 35 cases, few stained cells in 8 cases, and no C9 deposition in the 21 other cases. The last group showed no staining area. To avoid nonspecific C9 staining due to tissue autolysis, we studied C9 expression during a controlled putrefactive process in four cases included in group 1; staining was found only in infarcted myocardial areas, and was observed up to ten days. Specificity of C9 expression was evaluated to be 100% [89.4 to 100%] and sensitivity to be 85% [62.11 to 96.79%]. In conclusion, evaluation of immunohistochemical expression of C9 appears to be a highly sensitive and specific marker of early myocardial infarction, useful in forensic medicine if survival is more than 1 h after the beginning of myocyte damage.     

NIST mixed stain studies #1 and #2: interlaboratory comparison of DNA quantification practice and short tandem repeat multiplex performance with multiple-source samples

The Mixed Stain Study 1 (MSS1, Apr.-Nov. 1997) and Mixed Stain Study 2 (MSS2, Jan.-May 1999) evaluated multiplexed short-tandem repeat (STR) DNA typing systems with samples containing DNA from more than one source. These interlaboratory challenge studies evaluated forensic STR measurement, interpretation, and reporting practice using well-characterized samples of very different analytical difficulty. None of the relatively few errors reported in either exercise resulted in a false identification of a reference source; several errors in evaluating the unknown source in three-source samples would hinder matching the profile in any archival database. None of the measurement anomalies reported is associated with any particular STR multiplex; all DNA amplification anomalies are associated with inefficient DNA extraction, inaccurate DNA quantitation, and/or analytical threshold policies.     

Glycine toxicity and unexpected intra-operative death

A rare complication of the use of glycine irrigation fluid during prostatic surgery in a 69-year-old man is described. Following cystolithopexy and transurethral resection of the prostate for benign prostatomegaly, abdominal distension developed with increasing ventilatory pressures. Despite retroperitoneal fluid evacuation at subsequent urgent laparotomy, cardiac arrest occurred that was not amenable to resuscitation. At autopsy a traumatic defect in the posterior bladder wall filled with calculus debris was confirmed that did not communicate with the peritoneal cavity. Hyponatremia with markedly elevated levels of blood, urine, and body fluid glycine were demonstrated. Death was, therefore, attributed to glycine toxicity following tracking of glycine through a surgical defect in the posterior bladder wall. Careful dissection of surgical sites is required in such cases to demonstrate any additional trauma that may be associated with the fatal episode. Analysis of body fluids for glycine and electrolytes is also necessary to assist in the determination of possible mechanisms of death.     

Forensic chemical testing of cadaveric material for acetonitrile

Gas chromatographic conditions for qualitative and quantitative evaluation of acetonitrile in biological material were determined, including those for reactive gas chromatography. Absolute and relative time of acetonitrile and concomitant substances retention in three columns of different polarity was determined. Study of the time of acetonitrile retention in biological material showed that acetonitrile concentration in the blood virtually did not change in cadaveric material stored in a hermetically closed flask for 2 weeks at 20 +/- 3 degrees C, while its concentration in the stomach decreased by 10-15%. Distribution of acetonitrile in human viscera in lethal poisoning was studied; the agent was evenly distributed in the gastric wall, intestine, liver, and kidney, while its concentrations in the lung and brain were 2-3 times higher. Forensic chemical expert analyses of the blood, urine, and viscera from corpses of humans dead from lethal acetonitrile poisoning showed that lethal concentration in the blood was 28.3-57.0 mg and in the urine 23.2-40.6 mg/100 ml.