Death associated with volatile substance inhalation--histologic, scanning electron microscopic and energy dispersive X-ray spectral analyses of lung tissue

The investigation of deaths due to the inhalation of volatile substances may be complicated by a lack of scene and autopsy findings. Mechanisms of death may not be determinable at autopsy, and there may be very few markers of inhalant abuse. A 21-year-old man is reported who died from the combined effects of methadone toxicity and toluene inhalation. Histological examination of the lungs revealed congestion and edema, as well as particles of blue, pigmented material within the interstitium and in macrophages. Scanning electron microscopy was undertaken, revealing that the particles contained granules that measured 0.15-0.2microm in diameter, within the range of mean particle sizes for inorganic paint pigments. Energy dispersive X-ray spectral analysis of the granules demonstrated a significant percentage of titanium (12%) confirming their origin from paint. Ancillary investigations such as electron microscopy and X-ray spectral analysis in cases of possible lethal volatile inhalation may prove useful adjuncts in determining the type of substance inhaled and in providing evidence of previous non-lethal episodes.     

Validation of reduced-scale reactions for the Quantifiler Human DNA kit

Accurate quantification of DNA samples is an important step in obtaining accurate and reproducible short tandem repeat (STR) profiles. Quantitative real-time-PCR has improved the speed and accuracy of DNA quantification over earlier methods, albeit at significantly greater cost per reaction. Here, the performance of reduced volume (10 microL) DNA quantification assays using the Quantifiler Human DNA Quantification Kit was evaluated using commercial standards and single source biological stains (e.g., venous blood, saliva, and semen). In addition, casework-type samples including those subjected to environmental contaminants containing PCR inhibitors and samples having undergone extensive DNA degradation were also quantified. The concentration of DNA in various forensic samples ranged from 0 to 2.9 ng/microL depending on sample source and/or environmental insult. Compared to full-scale reactions, reduced volume assays displayed equivalent to improved amplification efficiency and sample-to-sample reproducibility (+/-0.01-0.17 C(T FAM)). Furthermore, the use of data from reduced-scale Quantifiler reactions facilitated the accurate determination of the amount of sample DNA extract needed to generate quality STR profiles. The use of 10 microL-scale Quantifiler reaction volumes has the practical benefit of increasing the effective number of reactions per kit by 250%; thereby reducing the cost per assay by 60% while consuming less sample. This is particularly advantageous in cases of consumptive testing.