Population genetic data of eight tetrameric short tandem repeats (STRs) in Casablanca resident population to use in forensic casework

The allele frequencies for eight short tandem repeat (STR) loci HUMvWA, HUMFES/FPS, HUMF13A, HUMF13B, HUMTHO1, HUMTPOX, HUMCSF1P0, HUMLPL included in Geneprint STR kits were obtained from 234 unrelated individuals in Casablanca.     

An evaluation of the Cozart RapiScan system as an on-site screening tool for drugs of abuse in a non-conventional biological matrix: vitreous humor

The aim of this project was to evaluate the Cozart RapiScan Oral fluid Drug Testing System as an on-site screening tool for vitreous humor samples collected during post-mortem examinations. Vitreous humor is easy to collect and as it is contained within the eye it is almost completely unaffected by post-mortem redistribution. The ability to carry out an initial drug screen on vitreous humor at the earliest stage of the death investigation process could contribute significantly to the assessment of the role drugs may have played prior to confirmation with toxicological analyses at the laboratory. Vitreous humor (n = 146) was collected from autopsy examinations (111 males and 35 females) with a specific focus on cases where death occurred following a road traffic accident or where an overdose was suspected. All samples were screened using the five-panel methadone Cozart RapiScan Cartridge with an overall positive rate of 29%. Of the positive results, 43% screened positive for benzodiazepines, 17% for cocaine, 7% for methadone and 33% for opiates. Positive samples, with the exception of benzodiazepines, and 20% of negative samples were analysed by GC/MS. This is the first reported use of this system as an on-site forensic tool in death investigation and for screening for drugs of abuse in vitreous humor. The conclusions from this study show that the Cozart RapiScan System could play an important role in obtaining information on the toxicological state of the person at the time of death.     

A comparison of efficiency of manual and automatic fibres search with the Maxcan fibre finder

The aim of this work was to study the efficiency of automatic fibre searching with the Maxcan fibre finder (Cox Analytical Systems, Sweden) in comparison to manual searching. The influence of some parameters (color, thickness, background noise) on the results of a fibre search was considered. Eighteen experimental tapes with different target fibres and different background noises were prepared in the laboratory. Searching of fibres was performed manually and with the Maxcan fibre finder by different operators from four European laboratories. Two laboratories have the Maxcan fibre finder system and the two instruments were used and compared in this study. The results show that searching with the Maxcan is generally as efficient as manual searching, except for very pale or very dark fibres. Note that the tapes used for these experiments were prepared in laboratory, and are not completely representative of the tape that could be obtained in real cases. To generalize the results obtained, further research on real case samples would be necessary.     

Correlation of Delta9-tetrahydrocannabinol concentrations determined by LC-MS-MS in oral fluid and plasma from impaired drivers and evaluation of the on-site Dräger DrugTest

Oral fluid (collected with the Intercept((R)) device) and plasma samples were obtained from 139 individuals suspected of driving under the influence of drugs and analyzed for Delta(9)-tetrahydrocannabinol (THC), the major psychoactive constituent of cannabis, using a validated quantitative LC-MS-MS method. The first aim of the study was to investigate the correlation between the analytical data obtained in the plasma and oral fluid samples, to evaluate the use of oral fluid as a 'predictor' of actual cannabis influence. The results of the study indicated a good accuracy when comparing THC detection in oral fluid and plasma (84.9-95.7% depending on the cut-off used for plasma analysis). ROC curve analysis was subsequently used to determine the optimal cut-off value for THC in oral fluid with plasma as reference sample, in order to 'predict' a positive plasma result for THC. When using the LOQ of the method for plasma (0.5 ng/mL), the optimal cut-off was 1.2 ng/mL THC in oral fluid (sensitivity, 94.7%; specificity, 92.0%). When using the legal cut-off in Belgium for driving under the influence in plasma (2 ng/mL), an optimal cut-off value of 5.2 ng/mL THC in oral fluid (sensitivity, 91.6%; specificity, 88.6%) was observed. In the second part of the study, the performance of the on-site Dr?ger DrugTest for the screening of THC in oral fluid during roadside controls was assessed by comparison with the corresponding LC-MS-MS results in plasma and oral fluid. Since the accuracy was always less than 66%, we do not recommend this Dr?ger DrugTest system for the on-site screening of THC in oral fluid.     

Validation of a large Italian Database of 15 STR loci

Results from a collaborative exercise with proficiency testing conducted by 20 Italian laboratories on the 15 loci included in the Identifiler kit were analyzed by allele sharing methods and by standard population genetics tests. The validated database, including about 1500 subjects, was merged with that of a previous exercise conducted on nine loci, and the resulting allele frequencies, subdivided by Italian region, were published on-line.     

Development of a pentaplex X-chromosomal short tandem repeat typing system and population genetic studies

Quadruplex and pentaplex systems for polymerase chain reaction amplification of X-chromosomal short tandem repeats DXS101, HPRTB, DXS8377, DXS981 (STRX1) and DXS6789 were developed for automated profiling of liquid and membrane-bound DNA samples. Chinese, Japanese and Thai populations were typed using a quadruplex system, while German and Philippine populations were analyzed using a five-locus system. Out of 88 meioses studied in Philippine family samples at each locus, a possible one repeat deletion (allele 51 to 50) at DXS8377 was observed in a father-daughter pair. Exact tests performed on genotype data from females in the Philippine, German and Thai populations indicated that these groups conform to Hardy-Weinberg equilibrium. Exact tests for population differentiation indicate significant variations in allele distributions, particularly at loci DXS101, DXS981 and DXS6789. Considered individually, DXS8377 was the most polymorphic and HPRTB the least polymorphic locus in these five populations. When the forensic efficiency of the quadruplex system was calculated, the combined power of discrimination among males (PD(M)) was no lower than 0.998, while among females the combined PD(F) was at least 0.9999 in all populations. The combined power of paternity exclusion was a minimum of 0.998 in trio cases and 0.98 in motherless cases. The addition of locus DXS6789 to the German and Philippine population databases using a pentaplex increased the forensic efficiency of the analysis system.     

A singular case of murder-suicide committed with a homemade firearm

The authors illustrate a peculiar case of murder-suicide committed with a homemade firearm loaded with 12-gauge cartridges (buckshot). The structure and function of this handcrafted firearm were simple but effective: an iron tube did duty as a barrel in this primitive firearm. The cartridges (modified by winding sticky tape around the external surface of the base) were inserted down one end of the tube (serving as the breech). A second iron tube with a larger diameter (so as to be able to run over each of the preloaded barrels) and with a jutting, cone-shaped metal wedge soldered to the base, was used as a rudimental firing pin. After loading the "barrel" with the modified cartridge, the gunman would ram the "firing pin" tube violently down to fire the shot. Autopsy of the woman's body showed the presence of 3 gunshot wounds caused by buckshot, while the man had a single buckshot wound in the head. Subsequent ballistic investigations enabled reconstruction of the event (typical of murder-suicide) and the functioning of the firearm, demonstrating its lethal nature, remarkably easy handling, and simplicity of production.     

Population data for 12 Y-chromosome STRs in a sample from Brescia (northern Italy)

Twelve Y-chromosome STRs--DYS19, DYS389-I, DYS389-II, DYS390, DYS391, DYS392, DYS393, DYS385, DYS437, DYS438, DYS439--were typed in a population sample (n=104) of unrelated males from Brescia (northern Italy). A total of 91 haplotypes were identified by the 12 Y-STR loci. The haplotype diversity (98.68%), discrimination capacity (87.50%) and gene diversity were calculated.     

Fatal workplace accident involving ethyl acetate: a distribution study

The tissue distribution of ethyl acetate and ethanol in a case of acute intoxication by ethyl acetate is presented. The victim was a 39-year-old man who was found dead lying on his abdomen in the interior of a tank containing ethyl acetate. Confirmation of ethyl acetate was obtained with static headspace gas chromatography with mass spectrometry. In blood, rapid biotransformation of ethyl acetate occurs by plasma esterases resulting in acetic acid and ethanol. Quantitation of ethyl acetate and ethanol in the postmortem samples was performed using static headspace gas chromatography with flame ionization detector. N-butanol was used as internal standard. Separation of the compounds was obtained on a Supelcowaxtrade mark-10 Fused Silica capillary column. The method was linear over the specific ranges investigated and showed a within-run accuracy of 99.8 and 101.0% and a precision of 0.5 and 2.0% for ethanol and ethyl acetate, respectively. The postmortem samples were analyzed in duplicate or triplicate. Coefficients of variation were < or =4.51% for ethyl acetate and < or =0.52% for ethanol. The low ratios of the ethyl acetate concentration to the ethanol concentration found in the postmortem tissue samples confirmed the rapid in vivo biotransformation of ethyl acetate. The highest concentration of ethyl acetate was found in the testis indicating that postmortem percutane absorption may have occurred. To our knowledge, this is the first reported tissue distribution study of ethyl acetate and ethanol in a case of acute intoxication by ethyl acetate.