Formation of an interfering substance, 3,4-dimethyl-5-phenyl-1,3-oxazolidine, during a pseudoephedrine urinalysis

During fatal aviation accident investigations, biosamples from the victims are submitted to the FAA Civil Aeromedical Institute (CAMI) for drug analysis. In the process of one such analysis by CAMI, an unknown substance was found in a urine sample. Simultaneous screening by thin layer chromatography (TLC) and gas chromatography/FID (GC/FID) suggested the presence of pseudoephedrine. A subsequent routine confirmation analysis of a separate urine aliquot by GC Fourier transform infrared (GC/FTIR) and GC mass spectrometry (GC/MS) indicated that the retention times of the unknown substance matched with those of pseudoephedrine. However, its infrared and mass spectra were different--the -OH and -NH groups were missing, a C-O-C group was present, and the molar mass was 12 atomic mass units (amu) more than that of pseudoephedrine. A subsequent literature search suggested that ephedrine-like amines react with aldehydes to form oxazolidines. Therefore, the 12-amu increase could be accounted for by condensation of pseudoephedrine with formaldehyde. Since this aldehyde is present in various grades of methanol and ethyl acetate, and these solvents were used during the solid-phase extraction, 3,4-dimethyl-5-phenyl-1,3-oxazolidine was synthesized by using (+)-pseudoephedrine HCl and formaldehyde. The analytical findings of the synthesized compound were consistent with those of the unknown interfering substance, confirming that it was the oxazolidine. Aldehyde contaminants in solvents or specimens can transform drugs of interest and may result in misidentification of a compound originally present in specimens. Therefore, chemicals used in analyses should be of the highest available purity, and a multi-analytical approach should be adopted to maintain a high degree of quality assurance.     

Unusual cases of suicide among health care workers

We describe three unusual cases of suicide committed by health care workers. The aim of this paper was to analyze and evaluate the evidence of general diagnostic elements of poisoning in these cases.     

Expert significance of evaluating volatile non-metal combustion products in analysis of blood from subjects dead in fire

Qualitative and quantitative composition and time course of formation of toxic substances during burning of polymers have been studied for two polymers, P-53-P and STBO. The most toxic gaseous products of nitrogen combustion are listed: hydrogen cyanide, nitrites, acid nitriles, aldehydes, aromatic carbohydrates, alkanes, and carbon oxide. Two expert conclusions are presented, including analysis of blood and viscera from subjects who died during fire. The following toxic substances were detected: carbon oxide, hydrogen cyanide, nitrites, acrylonitrile, acetonitrile, benzene, and methane in one case and the same products except carbon oxide in the other. The author considers that the list of tested toxic substances should be extended, particularly in cases with negative results of blood testing for carbon oxide and carboxyhemoglobin.     

Advances in the diagnosis of wound vitality: a review

The diagnosis of the vital origin of wounds in many cases remains an unsolved problem for the forensic pathologist. Practical experience enables the expert to diagnose the vital or postmortem origin of wounds on the basis of macroscopic examination. In some cases, optic microscopy is used to confirm the diagnosis. In many other cases, additional more sensitive and specific markers of vitality are required. In the past 50 years, comprehensive research on this topic has resulted in a better understanding of the acute inflammatory reaction. The development and application of sensitive and specific markers through research in the areas of histochemistry, enzymology, and biochemistry has provided a partial solution to the problems involved in wound vitality diagnosis. A review of this challenging area of forensic pathology, including an explanation of these methods and markers, is presented in this paper.     

Arterial-esophageal fistulae in patients requiring nasogastric esophageal intubation

A rare and potentially fatal cause of hematemesis is fistula formation between the esophagus and the vascular system. A case report of a 39-year-old woman with congenital aortic arch anomalies hospitalized for treatment of head injuries demonstrates the potential for iatrogenic esophageal trauma to initiate fistula formation between the esophagus and an anomalous arterial system. A literature review revealed 6 other cases of vascular-esophageal fistulae caused by nasogastric esophageal intubation. It is concluded that aortic arch anomalies increase the risk of esophageal injury and subsequent fistula formation from nasogastric esophageal intubation. In addition, the clinical features and pathologic findings of vascular-esophageal fistulae are reviewed.     

A deadly anti-SIDS device

The diagnosis of sudden infant death syndrome (SIDS) has been an enigma to medical examiners and coroners for decades. The recent drastic decrease in the number of SIDS cases has been associated with infants sleeping supine instead of prone. The apparent relation between sleeping position and SIDS has led to the marketing of several positioning sleep aids. We report a case of the improper use of one such device which resulted in the death of an infant.