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.     

DNA typing of samples for polymarker, DQA1, and nine STR loci from a human body exhumed after 27 years

A body was exhumed from the ground after 27 years. Samples of femur bone, tooth, and a fingernail were collected and successfully subjected to DNA extraction, quantitation, amplification, and subsequently typed for DQA1, polymarker, and nine STR loci. All three types of samples were typed for D3S1358, vWA, FGA, D8S1179, D21S11, D18S51, D5S818, D13S17, D7S820, and amelogenin using ABI Prism 377 DNA sequencer.     

The Frye hearing in Florida: an attempt to exclude scientific evidence

State Supreme Courts require a minimum threshold of reliability and acceptance in the scientific community for all medical and similar evidence to be admitted at trial. In Florida and some other states, the courts adhere to what is known as the Frye standard, whereas in most states and in Federal Courts, it is the so-called Daubert standard. The jurisdiction of the present case is Hillsborough County (Tampa), Florida. Forensic pathologists seldom, if ever, are requested to participate in such hearings, unlike their toxicological and basic science colleagues who are more involved in research methodology and technical procedures. The burden is on the proponent of the evidence to prove the general acceptance of both the underlying scientific principle of the test and procedures used to apply that principle to the facts of the case at hand. The trial judge has the sole discretion to determine this question and general acceptance must be established by a preponderance of the evidence. The authors describe in detail a hearing in a case in which they were all involved. One author (WQS) had researched and documented the original scientific methodology in the literature. The situation involved a car and tractor trailer crash with the two occupants of the car dying of multiple trauma, whereas the truck driver was not injured. Autopsy of the auto driver revealed multiple injuries with exsanguination, and only vitreous humor and liver tissue, but not blood, were tested for ethyl alcohol. The estate of the driver of the automobile brought suit against the owner of the trucking company for wrongful death. The plaintiff requested a Frye hearing to question the reliability of testing other body specimens to translate to probable blood alcohol level. The testimony, submitted documents, and eventual decision by the judge are discussed.     

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.     

Population genetics of HPRTB, F13B, and LPL in Pernambuco, Northeast Brazil

One hundred thirty-four unrelated Northeast Brazilian individuals were typed for the HPRTB, F13B, and LPL short tandem repeats (STRs). DNA was amplified by specific primers and identified by silver staining of polyacrylamide gels. The allelic frequencies of these loci were in agreement with Hardy-Weinberg proportions. The most frequent alleles were HPRTB*13, F13B*10, LPL*10. The combined probability of paternity and the discrimination power of these 3 STRs were high, permitting their utilization for forensic science purposes.     

The Slovenian population data on the PCR based loci HLA-DQA1, LDLR, GYPA, HBGG, D7S8, GC, and D1S80

Allele frequencies for the loci HLA-DQA1, LDLR, GYPA, HBGG, D7S8, GC, and D1S80 were determined for a sample population of unrelated individuals from Slovenia. All loci meet Hardy-Weinberg expectations, except the loci GYPA (p = 0.041) and D1S80 (p = 0.009). There is little evidence for association of alleles among the seven loci. Only one out of 21 pairwise comparisons demonstrated departures from independence (HLA-DQA1/HBGG, p = 0.008). The allelic frequency data generally are similar to that of U.S. Caucasians.     

A sandwich enzyme-linked immunosorbent assay for ABO blood typing of semen by using anti-p 84 monoclonal antibody as a marker of blood group substance in semen

A blood group substance (BGS), a protein with ABH antigenic activity, was isolated from human seminal plasma and designated as p 84 (Sato, 1995). We have developed a method for determining the ABO blood type of semen by performing a sandwich enzyme-linked immunosorbent assay (ELISA) in which p 84 is captured with an anti-p 84 monoclonal antibody, and evaluated the specificity and sensitivity of this method. Although BGS activity was detected in semen sensitively by this method, it was not detected in saliva, urine, breast milk, blood or vaginal secretions. Since the concentration of p 84 in semen was independent of the secretion status, the status can be determined as non-secretor when p 84 but not BGS activity was detected. To determine the stability of BGS activity on p 84, dried stains of semen on filter paper were kept at 4, 26, and 37 degrees C for 8 months, 2 years and 1 month, respectively, and their BGS activities were examined. After 8 months at 4 degrees C, over 60% of the original BGS activity was recovered from the stain. The activity could be detected even from a square as small as 0.25 by 0.25 cm. After 1 month at 37 degrees C and 2 years at 26 degrees C, 31 and 20% of the BGS activity, respectively, still remained. It could be detected from the pieces of 1.0 by 1.0 cm and 0.5 by 0.5 cm squares, kept for 1 month at 37 degrees C and 2 years at 26 degrees C, respectively. Finally, semen was mixed with saliva or blood at varying volumetric ratios and used for the sources of dried stains. The BGS activity of p 84 could be detected in the stains until the ratio between semen and saliva or blood reached 1:4. We conclude that this sandwich ELISA offers a more sensitive and specific method for determining the ABO blood type of semen samples obtained from sexual assault victims than existing methods, such as the conventional absorption-elution and classical hemagglutination-inhibition tests.     

Comparison of patterns of decomposition in a hanging carcass and a carcass in contact with soil in a xerophytic habitat on the Island of Oahu, Hawaii

Decomposition studies were conducted to determine differences in rates and patterns of decomposition of carcasses hanging and exposed on the surface of the soil. These studies were conducted between 17 October and 17 December 1997 inside of Diamond Head Crater on the island of Oahu, Hawaii. The animal model was the domestic pig. Sus scrofa. The rate of biomass removal from the hanging carcass was significantly slower than that observed for the control carcass during the bloat and decay stages of decomposition. Internal temperatures for the control carcass were elevated above the ambient air temperatures during the earlier stages of decomposition (bloated and decay), while those recorded for the hanging carcass approximated the ambient air temperatures. There was a greater diversity of arthropod species recorded and numbers of individuals observed were higher for the control carcass. A significant site of arthropod activity was observed on the surface of the soil immediately under the hanging carcass and this became the primary site of arthropod activity as decomposition progressed.     

Suicide by electrocution with low-voltage current

Three cases of suicide by electrocution with low-voltage current were observed in five years (1994-1998) by medical clinical forensic examiners of an Emergency Forensic Unit of the Paris suburb among 2,000 external death examinations. The cases involved one woman, aged 72 and two men, aged 38 and 41. In the last two cases, electric burns were retrieved under bared electric wires, placed on the arms or fingers in order to realize a hand-to-hand electric circuit involving the heart muscle. In the other case, the electric circuit between mouth and foot also involved the heart muscle. Household low-voltage current delivered (220 V in France) had a sufficient strength to induce local muscular paralysis and heart fibrillation. In the three cases, blood samples taken have retrieved very high levels of muscular enzymes (CPK, LDH) correlated to the mechanism of electric death. The rareness of suicide by electrocution and its forensic characteristics are detailed in order to help the clinical forensic examiners, prosecutors, and police officers concerned by such death examinations.