Oral Cavity Fluid as an Alternative Postmortem Matrix: Comparison to Simultaneously Collected Blood and Urine Specimens.

ABSTRACT: In postmortem toxicology analysis, a variety of specimens consisting of fluids and tissues are often collected, each with an intrinsic value. Oral cavity fluid (OCF) is emerging as an alternative matrix in forensic toxicology for contributing to a diagnosis in postmortem cases; especially when blood is limited or not available. The aim of this study was to assess the analytical results obtained from OCF and compare them with blood, urine, and other traditional matrices collected from the same postmortem subjects. Of the 62 decedents studied (including 1 stillborn, 1 charred, and 3 decomposed subjects), 56 had quantifiable drugs and metabolites data in the OCF, blood, and urine. Notable findings were benzoylecgonine (24 cases), ethyl sulfate (23 cases), acetaminophen (21 cases), morphine (21 cases), naloxone (21 cases), gabapentin (20 cases), fentanyl (17 cases), and 6-acetylmorphine (15 cases), which were detected more frequently in OCF than in blood (heart, femoral, or body cavity) or urine. This study suggests that OCF is a suitable matrix for detecting and quantifying analytes in postmortem subjects compared with traditional matrices, particularly when other matrices are limited or difficult to collect because of body condition or putrefaction.

Strain-related differences in urine composition of male rats of potential relevance to urolithiasis.

In carcinogenicity studies with PPAR gamma and alpha/gamma agonists, urinary bladder tumors have been reported in Harlan Sprague-Dawley (HSD) and Charles River Sprague-Dawley (SD) but not Wistar (WI) rats, with urolithiasis purported to be the inciting event. In two 3-month studies, the authors investigated strain-related differences in urine composition by sampling urine multiple times daily. Urine pH, electrolytes, creatinine, protein, citrate and oxalate levels, and serum citrate were assessed; urine sediment was analyzed by scanning electron microscopy and energy dispersive x-ray spectroscopy. HSD rats had significantly higher urine calcium than SD or WI rats, primarily as calcium phosphate-containing precipitate. When compared to SD rats, HSD rats had lower urine volume, higher urine protein, and a comparable (week 4) to lower (week 13) burden of MgNH(4)PO(4) aggregates. Relative to WI rats, HSD rats had higher urine protein and magnesium and lower serum and urine citrate. Overall, the susceptibility to urolithiasis in male rats was HSD > SD > WI; this was likely due to strain-related differences in the amount of urine protein (a nidus for crystal formation), lithogenic ions, citrate (an inhibitor of lithogenesis), and/or volume. Strain-related differences in urine composition need to be considered when interpreting the outcome of studies with compounds that alter urine composition.

Oral Cavity Fluid as an Investigative Approach for Qualitative and Quantitative Evaluations of Drugs in Postmortem Subjects.

A relatively overlooked aspect of forensic science is the potential of oral cavity fluid for contributing to a forensic diagnosis. Although traditional specimens, like blood and urine, are routinely evaluated for forensic toxicology testing, fluid from the oral cavity has not been investigated as a matrix in postmortem cases. Our laboratory developed and validated qualitative and quantitative analytical methods for determining 47 medicinal and illicit drugs from oral cavity fluid. These developed methods aimed to compare results from liquid chromatography coupled with tandem mass spectrometry (LC-MS/MS) analyses of oral cavity fluid to those of traditional matrices collected from the same postmortem subjects. Of 34 cadavers studied, 32 (including two decomposed and two drowned subjects) had detectable and quantifiable drugs in the oral cavity fluid and/or blood, urine, bile, vitreous fluid and/or liver tissue. The most significant finding was that 6-acetylmorphine (6-AM) was detected more frequently in oral cavity fluid (11 cases) than in blood and urine combined (6 cases). Compounds with a short window of detection, like the heroin metabolite, 6-AM and even heroin, could be detected more readily in oral cavity fluid than in urine. In 2017, the incidence of heroin-related overdose deaths increased to 15,958. Those data have shed light on the practicality of testing oral cavity fluid postmortem and its significance in forensic toxicology. In conclusion, this study showed that oral cavity fluid could be useful for detecting and quantifying drugs in postmortem subjects; moreover, oral cavity fluid may be particularly suitable when other matrices are limited or difficult to collect, due to body condition or putrefaction.

Dietary ammonium chloride for the acidification of mouse urine.

A novel therapeutic compound was found to induce bladder tumors in male rats. Given the location of the tumors and the increased amounts of calcium- and magnesium-containing solids found in the urine of treated animals, we hypothesized that tumorigenesis was secondary to urine crystal formation rather than a direct effect of the drug on urothelium. To investigate the basis for the response, a method of acidifying rodent urine was needed. This study tested the efficacy of 1% dietary NH(4)Cl in reducing the urinary pH of male mice. After 1 wk, urinary pH (mean +/- SD) at 1 h after light onset was 7.51 +/- 0.32 among controls compared with 6.21 +/- 0.31 for the NH(4)Cl-fed group. After 2 wk of supplementation, urinary pH was 7.78 +/- 0.41 for controls and 6.20 +/- 0.30 for the NH(4)Cl-fed group. To investigate whether the time of collection altered urinary pH, samples also were collected 8 h after the start of the light cycle on the day of the 2-wk collection. Urinary pH was 7.12 +/- 0.28 for the control group and 5.80 +/- 0.23 for the NH(4)Cl-fed mice. The pH differences between control and NH(4)Cl-fed groups and the differences in pH within groups at 1 and 8 h were statistically significant. Dietary NH(4)Cl is an effective urinary acidifier for mice. When evaluating the pH of mouse urine, care should be taken to compare samples collected at the same time after the start of the light cycle.