Forensic identification of dyes extracted from textile fibers by liquid chromatography mass spectrometry (LC-MS)

LC-MS is used for the identification of dyes extracted from textile fibers and the utility of the method for forensic trace analysis is demonstrated. The technique is shown to provide a high degree of chemical structural information, making dye identification highly specific in comparison to optical and/or chromatographic methods of dye analysis. A UV-visible absorbance detector, placed in series before the MS detector, facilitates monitoring the elution of dyes in the presence of other non-dye components extracted from colored textile fibers. In this way, dye identification becomes practical, even when a dye standard is not available for comparison. A set of 22 reference dyestuffs and 10 dyes extracted from textile fibers were analyzed to demonstrate the utility of the method. Six of the extracted dyes corresponded to dyes also contained in the set of 22 reference dyestuffs. Reference dyestuffs were not available for four of the extracted dyes. Triethylamine (TEA) was shown to increase the electrospray ionization-mass spectrometry (ESI-MS) response of dyes containing multiple sulfonated groups.     

Validation study of the TrueAllele automated data review system

The New York State Convicted Offender DNA Databank is the first U.S. lab to complete an internal validation of the TrueAllele expert data review system. TrueAllele is designed to assess short tandem repeat (STR) DNA data based on several key features such as peak height, shape, area, and position relative to a standard ladder and use this information to make accurate allele calls. The software then prioritizes the allele calls based on several user-defined rules. As a result, the user need only review low-quality data. The validation of this system consisted of an extensive optimization phase and a large concordance phase. During optimization, the rule settings were tailored to minimize the amount of high-quality data viewed by the user. In the concordance phase, a large dataset was typed in parallel with the ABI software Gene Scan and Genotyper (manual review) and TrueAllele (automated review) for comparison of allele calls and sample state assignment. Only one significant difference was discovered out of 2048 samples in the concordance study. In this case, TrueAllele revealed a spike in the profile that was interpreted as a DNA peak by the analyst in Genotyper. TrueAllele was designed to focus the review on poor data and to eliminate the need for complete reanalysis technical review. This validation project proved TrueAllele to be dependable for use at the NYS Convicted Offender DNA Databank.     

Analysis of nitrite in adulterated urine samples by capillary electrophoresis

A simple method for analyzing nitrite in urine has been developed to confirm and quantify the amount of nitrite in potentially adulterated urine samples. The method involved separation of nitrite by capillary electrophoresis and direct UV detection at 214 nm. Separation was performed using a bare fused silica capillary and a 25 mM phosphate run buffer at a pH of 7.5. Sample preparation consisted of diluting the urine samples 1:20 with run buffer and internal standard, and centrifuging for 5 min at 2500 rpm. The sample was hydrodynamically injected, then separated using -25 kV with the column maintained at 35 degrees C. The method had upper and lower limits of linearity of 1500 and 80 microg/mL nitrite, respectively, and a limit of detection of 20 microg/mL. The method was evaluated using the National Committee for Clinical Laboratory Standards (NCCLS) protocol (Document EP10-A2), and validated using controls, standards, and authentic urine samples. Ten anions, ClO-, CrO4(-2), NO3-, HCO3-, I-, CH3COO-, F-, SO4-, S2O8(-2), and Cl-, were tested for potential interference with the assay. Interferences with quantitation were noted for only CrO4(-2) and S2O8(-2). High concentrations of Cl- interfered with the chromatography. The method had acceptable accuracy, precision, and specificity.     

A definition of the nomenclature of allele variants and a description of allele polymorphism within a molecular-genetic individualization system based on the pentanucleotide tandem replication of HUMCD4

While analyzing the available published data, we found significant differences in definition of alleles of the HUMCD4 polymorphic chromosome locus. It is an obstacle for comparing the expertise results obtained while using the locus as molecular individualization system in different laboratories and, as a consequence, it hinders the use of the said marker in building up a reference database. The structure of the HUMCD4 locus was analytically investigated and the distribution of the locus alleles was systemized in a sample of 407 persons (citizens of Russia who are not blood relatives) within the present case study for the purpose of a detailed definition of its allele's characteristics. We worked out recommendations related with the nomenclature standardization of alleles of the HIMCD4 locus and specified the main population features of the locus polymorphism on the bases of the studied sample of Russia's citizens. The results can be used as reference parameters in interpreting the findings of the molecular-genetic identification expertise and examinations and in building up databases.     

Toxicity of non-steroid anti-inflammatory drugs

Data are reported on toxicity of a majority of non-steroid anti-inflammatory drugs (NSAD), which are the most frequently used in clinical practice and whose chemical structures are different. The action mechanism and side effects of some NSAD, in particular, of diclofenac, ibuprofen and indometacin, are also in the focus of attention.     

Lineup Identification by Children: Effects of Clothing Bias

This study examined effects of clothing cues on children's identification accuracy from lineups. Four- to 14-year-olds (n = 228) saw 12 video clips of individuals, each wearing a distinctly colored shirt. After watching each clip children were presented with a target-present or target-absent photo lineup. Three clothing conditions were included. In 2 conditions all lineup members wore the same colored shirt; in the third, biased condition, the shirt color of only one individual matched that seen in the preceding clip (the target in target-present trials and the replacement in target-absent trials). Correct identifications of the target in target-present trials were most frequent in the biased condition, whereas in target-absent trials the biased condition led to more false identifications of the target replacement. Older children were more accurate than younger children, both in choosing the target from target-present lineups and rejecting target-absent lineups. These findings suggest that a simple clothing cue such as shirt color can have a significant impact on children's lineup identification accuracy.