Mitochondrial DNA error prophylaxis: assessing the causes of errors in the GEP'02-03 proficiency testing trial

A qualitative and quantitative analytical method was developed and validated for the determination of 49 licit and illicit drugs in oral fluid. Small oral fluid samples, volume 1mL, were collected from volunteers using a modified Omni-Sal device and the analytes were extracted from an oral fluid/buffer mixture using a single Bond Elut Certify solid phase extraction cartridge. Liquid chromatography-tandem mass spectrometry (LC-MS-MS) and gas chromatography-repetitive full scan mass spectrometry (GC-MS) were used in parallel to analyze the extracts for the targeted drugs. Extracts were analyzed by GC-MS in their underivatized form and as their pentafluoropropionyl derivatives. Deuterated internal standards were used for quantification of drugs of abuse by LC-MS-MS to minimize matrix effects. Methadone-d(9) and tumoxetine were used as the internal standards for quantification of non-derivatized and derivatized analytes respectively by GC-MS. Linearity was demonstrated over the range 5-200 ng/mL and limits of detection were less than 4 ng/mL for each drug analyzed. The method demonstrated acceptable recoveries for most of the analytes and good intra- and inter-day precision. Acquisition of data by repetitive full scan GC-MS allows the addition of further analytes to the target menu.     

A DNA microarray system for forensic SNP analysis

Forensic DNA analysis is routinely performed using polymorphic short tandem repeat (STR) markers. However, for degraded or minute DNA samples, analysis of autosomal single nucleotide polymorphisms (SNPs) in short fragments might be more successful. Furthermore, sequencing of mitochondrial DNA (mtDNA) is often performed on highly degraded or scarce samples due to the high copy number of mtDNA in each cell. Due to the increasing number of complete mtDNA genome sequences available, the limited discrimination power of an mtDNA analysis, may be increased by analysis of coding region polymorphisms in addition to the non-coding variation. Since sequence analysis of the coding region would require more material than generally present in forensic samples, an alternative SNP analysis approach is required. We have developed a one-colour microarray-based SNP detection system for limited forensic materials. The method is based on minisequencing in solution prior to hybridisation to universal tag-arrays. In a first outline of a forensic chip, a combination of 12 nuclear and 21 mitochondrial SNP markers are analysed simultaneously. The mitochondrial markers on the chip are polymorphisms within the hypervariable region as well as in the coding region. Even though the number of markers in the current system is limited, it can easily be extended to yield a greater power of discrimination. When fully developed, microarray analysis provides a promising system for efficient sensitive SNP analysis of forensic samples in the future.     

Linking arson incidents on the basis of crime scene behavior

The present study investigated the possibility of statistically linking arson cases based on consistency of behaviors from one crime scente to another. Serial and spree arson cases were studied to differentiate underlying themes and to link cases committed by the same offender. The material consisted of 248 arson cases which formed 42 series of arsons. A content analysis using 45 dichotomous variables was carried out and principal compnents (PCA) analysis was performed to identify underlying themes. Summary scores reflecting the themes were calculated. Linking effectiveness was tested with a discriminant analysis using the summary scores. The PCA analysis was successful and underlying themes which were in accordance with previous studies could be identified. Six factors were retained, in the PCA. The linking of the arson cases was possible to a satisfactory level: 33% of the cases could be correctly linked and for over 50% of the cases, the series they actually belonged to was among the ten series identified as most probable on the basis of the linking analysis. From a practical point of view, the results could be used as a basis for developing support systems for police investigations of arson. This research was financially supported by the Finnish Ministry of Interior and by Grant 54456 from the Academy of Finland.     

Legal and ethical issues in microbicides research and development in Canada

The Canadian AIDS Society (CAS) recently completed a report entitled Microbicides Development and Delivery in Canada: Legal, Ethical and Human Rights Issues. The report builds on Canadian and international experience and was written in consultation with Canadian community and international experts. It is available on the CAS website (www.cdnaids.ca) and from the Canadian HIV/AIDS Information Centre (www.aidssida.cpha.ca) as of September 2004. In this article the report's author, Anna Alexandrova, argues that Canada needs to develop a microbicides development and delivery strategy that addresses research and development issues, outlines possible roles for meaningful community participation, and provides guidelines on funding, promotion, licensing, and distribution.     

Relationships between the deinstitutionalization of healthcare for patients with mental disorder, substance abuse, and isolated death

Isolated death (ID) (i.e., dying alone without anyone noticing for several days) has been suggested to be related to social isolation, mental disorder, and alcohol and/or drug abuse. A major transfer of patients with a mental disorder and/or alcohol and/or drug abuse from institutionalized care to treatment as outpatients has been enacted in Sweden during the past decade. On the basis of the assumption that such deinstitutionalization is likely to result in increased social isolation, our working hypothesis was that the incidence of ID among patients belonging to these categories has increased in Sweden. The present study involved all deaths subjected to a medicolegal examination in Stockholm County (with a population of approximately 1.9 million people) during the period 1992-2000. The pattern of ID (defined as cases involving a postmortem delay between death and discovery of at least 1 week), as well as the incidence of fatalities subjected to medicolegal examination with a record of mental disorder and/or alcohol and/or drug abuse was evaluated. Throughout this period, the proportion of the deceased with a record of a mental disorder was high among all the cases examined and higher still among the cases of ID, especially among those younger than 65 years of age. There was a rather limited increase in the incidence of ID and a much more pronounced increase in the number of former psychiatric patients whose deaths were subjected to medicolegal examination, but did not satisfy the criteria for ID. A record of alcohol and/or drug abuse was more common than a diagnosis of mental disorder among both the males and females who died at an age of less than 65, with a clear difference between the cases of ID and non-ID in the case of men. There was no significant increase in incidence over the course of this study. Thus, this study reveals a slight increase in the number of IDs and a more pronounced increase in the number of medicolegal examination of non-IDs of individuals with a record of a mental disorder.     

Y-chromosome STR system, Y-PLEX 12, for forensic casework: development and validation

The Y-PLEX 12 system, developed for use in human identification, enables simultaneous amplification of eleven polymorphic short tandem repeat (STR) loci, namely DYS392, DYS390, DYS385 a/b, DYS393, DYS389I, DYS391, DYS389II, DYS 19, DYS439 and DYS438, residing on the Y chromosome and Amelogenin. Amelogenin provides results for gender identification and serves as internal control for PCR. The validation studies were performed according to the DNA Advisory Board's (DAB) Quality Assurance Standards. The minimal sensitivity of the Y-PLEX 12 system was 0.1 ng of male DNA. The mean stutter values ranged between 3.76-15.72%. A full male profile was observed in mixture samples containing 0.5 ng of male DNA and up to 400 ng of female DNA. Amelogenin did not adversely affect the amplification of Y-STRs in mixture samples containing male and female DNA. The primers for the Y-STR loci present in Y-PLEX 12 are specific for human DNA and some higher primates. None of the primate samples tested provided a complete profile at all 11 Y-STR loci amplified with the Y-PLEX 12 system. Y-PLEX 12 is a sensitive, valid, reliable, and robust multiplex system for forensic analysis, and it can be used in human forensic and male lineage identification cases.