Fast LC-MS/MS method for the determination of amphetamine, methamphetamine, MDA, MDMA, MDEA, MBDB and PMA in urine

A fast method was designed for the simultaneous determination of amphetamine (A), methamphetamine (MA), PMA, MDA, MDMA, MDEA and MBDB in urine. The drugs were analysed by LC (ESI)-MS/MS, after a simple liquid-liquid extraction in the presence of the deuterated analogues. Reverse phase separation on an Atlantis dC18 Intelligent Speed column was achieved in less than 4 min under gradient conditions, and the total run time was 8 min. The method was fully validated, including linearity (1-1000 ng/mL for A, MDMA, MDEA and MBDB; 2-1000 ng/mL for MDA and PMA; 1-200 ng/mL for MA; r2>0.99 for all compounds), recovery (>80%), within-day and between-day precision and accuracy (CV and MRE<12.7% for intermediate level and ULOQ, and <17.2% for LLOQ), limit of detection (0.2 ng/mL for MDMA, MDEA and MBDB; 0.5 ng/mL for A, MA and PMA; 1 ng/mL for MDA) and quantitation (1 ng/mL for A, MA, MDMA, MDEA and MBDB; 2 ng/mL for MDA and PMA) and relative ion intensities. No matrix effect was observed. The procedure proved to be sensitive, specific and rapid, and was applied to real forensic cases.     

Establishing identity using cheiloscopy and palatoscopy

Establishing a person's identity can be a very difficult process. Dental, fingerprint and DNA comparisons are probably the most common techniques used in this context, allowing fast and secure identification processes. However, since they cannot always be used, sometimes it is necessary to apply different and less known techniques. In this paper, the authors describe two unusual techniques: cheiloscopy and palatoscopy. It is known that due to their special features, both lip grooves and palatal rugae can be used successfully in human identification. This paper reviews the techniques of cheiloscopy and palatoscopy, and describes the different classifications and their advantages and limitations.     

Nucleotide variability of HV-I in Afro-descendents populations of the Brazilian Amazon Region

The analysis of genetic variation in the nucleotide sequences of mitochondrial DNA, provides unique information about the population diversity and human identification. In this study, the mitochondrial DNA sequences of the first hypervariable region (HV-I) were analyzed in 243 unrelated individuals of seven Afro-descendents populations of the Amazon Region. Sequence polymorphisms were detected using PCR and direct sequencing analysis. A total of 133 different haplotypes were found determined by 97 variable nucleotides. Each one of the three more frequent haplotypes was shared by 9 samples and 91 sequences were unique. The genetic diversity was estimated to 0.9898+/-0.0016 and the probability of two random individuals showed identical mitochondrial DNA (mtDNA) haplotypes were 1.2%.     

Analysis of body fluid mixtures by mtDNA sequencing: An inter-laboratory study of the GEP-ISFG working group

The mitochondrial DNA (mtDNA) working group of the GEP-ISFG (Spanish and Portuguese Group of the International Society for Forensic Genetics) carried out an inter-laboratory exercise consisting of the analysis of mtDNA sequencing patterns in mixed stains (saliva/semen and blood/semen). Mixtures were prepared with saliva or blood from a female donor and three different semen dilutions (pure, 1:10 and 1:20) in order to simulate forensic casework. All labs extracted the DNA by preferential lysis and amplified and sequenced the first mtDNA hypervariable region (HVS-I). Autosomal and Y-STR markers were also analysed in order to compare nuclear and mitochondrial results from the same DNA extracts. A mixed stain prepared using semen from a vasectomized individual was also analysed. The results were reasonably consistent among labs for the first fractions but not for the second ones, for which some laboratories reported contamination problems. In the first fractions, both the female and male haplotypes were generally detected in those samples prepared with undiluted semen. In contrast, most of the mixtures prepared with diluted semen only yielded the female haplotype, suggesting that the mtDNA copy number per cell is smaller in semen than in saliva or blood. Although the detection level of the male component decreased in accordance with the degree of semen dilution, it was found that the loss of signal was not consistently uniform throughout each electropherogram. Moreover, differences between mixtures prepared from different donors and different body fluids were also observed. We conclude that the particular characteristics of each mixed stain can deeply influence the interpretation of the mtDNA evidence in forensic mixtures (leading in some cases to false exclusions). In this sense, the implementation of preliminary tests with the aim of identifying the fluids involved in the mixture is an essential tool. In addition, in order to prevent incorrect conclusions in the interpretation of electropherograms we strongly recommend: (i) the use of additional sequencing primers to confirm the sequencing results and (ii) interpreting the results to the light of the phylogenetic perspective.     

A X-chromosome STR hexaplex as a powerful tool in deficiency paternity cases

The X-chromosome short tandem repeat (STR) markers have been described as very adequate tools for solving deficiency paternity cases and kinship tests when women are involved. In the absence of the alleged father, presumed paternal relationship can be more efficiently investigated by using a set of six to ten X-STR markers compared to fifteen autosomal STR. For this study, we compared the usefulness of a X-STR hexaplex developed in our laboratory (DXS7133, DXS7424, DXS8378, DXS6807, DXS7423 and DXS8377) and the commercial kit Identifiler in solving deficiency paternities. We have worked on distinct groups of caseworks involving daughters, their mothers and presumed paternal grandmothers or putative half sisters and their respective mothers. The PCR products were separated by capillary electrophoresis and detected in an ABI Prism 3100. In the majority of the caseworks (>90%), the likelihood ratio (LR) obtained by using the X-STR hexaplex was higher than the LR value observed when the Identifiler kit was used for genotyping. The combination of the two STR typing systems was able to solve all the cases.     

15 STR loci frequencies in the population from Santa Catarina, Southern Brazil

Allele frequencies for 15 short tandem repeats (STR) loci were determined with a sample of 3000 unrelated individuals from the population of Santa Catarina, Southern Brazil. The loci are most commonly used in forensic and paternity testing, being analyzed by the Powerplex 16 (Promega) commercial kit. The data shows that most polymorphic loci were Penta E and FGA. The distributions of the genotypes in the evaluated loci are in Hardy–Weinberg equilibrium. Comparative analyses between our population data and other Brazilian populations are presented. The calculated forensic parameters showed that the loci are useful for the solution of forensic problems in Brazilian Southern region.     

Cyberbullying in Portuguese Schools: Prevalence and Characteristics

This study examined the extent and nature of cyberbullying in 23 Portuguese schools. A sample of 3,525 sixth-, eighth-, and eleventh-grade students completed a self-response questionnaire assessing their perceptions and experiences of cyberbullying. The findings showed that 7.6% of students have been victimized, and 3.9% have bullied others at least once over the last year. The incidences of victimization were higher for females and for the older students. In contrast, more boys reported having bullied others in the eleventh grade. The most frequent medium of cyberbullying was via websites, whilst sending offensive messages was the most widely reported type of behavior. Telling someone about cyberbullying is among the most frequent coping strategies used by cybervictims, who usually chose to tell their friends rather than adults. Implications of these findings for students, schools, and parents are discussed.     

High‐Resolution Melting (HRM) of Hypervariable Mitochondrial DNA Regions for Forensic Science

Forensic strategies commonly are proceeding by analysis of short tandem repeats (STRs); however, new additional strategies have been proposed for forensic science. Thus, this article standardized the high‐resolution melting (HRM) of DNA for forensic analyzes. For HRM, mitochondrial DNA (mtDNA) from eight individuals were extracted from mucosa swabs by DNAzol reagent, samples were amplified by PCR and submitted to HRM analysis to identify differences in hypervariable (HV) regions I and II. To confirm HRM, all PCR products were DNA sequencing. The data suggest that is possible discriminate DNA from different samples by HRM curves. Also, uncommon dual‐dissociation was identified in a single PCR product, increasing HRM analyzes by evaluation of melting peaks. Thus, HRM is accurate and useful to screening small differences in HVI and HVII regions from mtDNA and increase the efficiency of laboratory routines based on forensic genetics.     

Extraction and isolation of cannabinoids from marijuana seizures and characterization by 1H NMR allied to chemometric tools

Marijuana, a drug derived from the Cannabis sativa L. plant, is the world's most consumed illicit drug. In this paper, a total of 156 marijuana samples seized in the state of Espírito Santo (ES), Brazil were studied and analysed by proton nuclear magnetic resonance (¹H NMR) spectroscopy to identify the major cannabinoids present. A crude extract of all samples was purified using high performance liquid chromatography so that these compounds could serve as reference substances. Nine fractions were obtained and analysed by ¹H NMR and gas chromatography–mass spectrometry (GC–MS), with five presented cannabinoids. ?⁹-THC (Δ⁹-trans-tetrahydrocannabinol), ?⁹-THCA (?⁹-tetrahydrocannabinolic acid), ?⁸-THC (?⁸-tetrahydrocannabinol), 11-hydroxycannabinol, CBV (cannabivarin), and CBN (cannabinol) were found, and their chemical structures were confirmed by GC–MS. The latter compound was obtained with high purity (≈100%), while the others were obtained as less complex mixtures with purity higher than 75% (except for Δ⁸-THC). Principal component analysis (PCA) was used on the ¹H NMR spectra of the 156 samples, and it was found that the samples were grouped according to the months, differentiating into two groups (from July 2014 to January 2015 and from February 2015 to July 2015), where non-grouping was observed from four macro-regions of the ES state (North, Central, Metropolitan, and South). The chemical profile of the seized samples was correlated to the ¹H NMR spectrum of an isolated CBN sub-fraction, in which the group formed by samples seized in the year 2015 presented lower CBN content in the chemical composition. From the PCA score plot, two groups of samples were confirmed using the partial least squares discriminant analysis and orthogonal projections to latent structures classification methods.