Spatial Distributions of Oxygen Stable Isotope Ratios in Tap Water From Mexico for Region of Origin Predictions of Unidentified Border Crossers

One of the many difficulties associated with identifying undocumented border crossers stems from an inability to narrow down the search area for the region of origin and family members to obtain family reference samples for DNA comparison. While the geography of regions of origins is wide, the biological profiles of the undocumented border crossers often show strong similarities, young and male. The isotopic composition of human bones, teeth, and hair has been demonstrated to be useful biomarkers for tracing locations and movements of individuals and for aiding in the identification of human remains. Data obtained from human remains can be compared to and aligned with various reference sources, such as soils and bedrock, archaeological remains, or cultural data. Here, the spatial deficiency in isotopic reference data for Mexico, specifically for oxygen (δ¹⁸O) isotopes in tap water, is being addressed through the collection and analysis of over 150 water samples and explored with tooth enamel isotopic values from recently identified Mexican nationals. The isoscape was developed using a Spine with Barriers interpolation method and shows sufficient detail to narrow down the regions where specific isotopic values are represented. The individuals were plotted on the developed isoscape using conditional correlations. The methodology was successful in assigning the correct regions of origin for the two individuals, which shows the tremendous potential of the developed isoscape. Nonetheless, there is more research needed to further improve upon this geolocation method, including analysis of multiple isotopes in different tissues, and the development of new isotopic methods.     

SCIENTIFIC‐BUREAUCRATIC MEDICINE AND UK HEALTH POLICY1

One prominent method for controlling health costs is to find measures for the management of demand. Various options exist for this; and many of them have been tried during the fifty years of the UK's National Health Service. Current policy now focuses on what may be called “scientific‐bureaucratic medicine.” This policy is based on the assumptions that valid medical knowledge is derived from accumulated research evidence and that such knowledge should be implemented through clinical guidelines which are enforced to some extent. This UK development has parallels with the US Agency for Health Care Policy and Research whose experience, therefore, raises some policy issues for the UK.     

Identifying the dead: methods utilized by the Pima County (Arizona) office of the medical examiner for undocumented border crossers: 2001-2006

The Pima County (Arizona) Office of the Medical Examiner has seen a dramatic rise over the past 6 years in the number of deaths related to the illegal crossing of our international border with Mexico. This rise in deaths is undoubtedly related to an increase in the number of foreign nationals who cross into the various Arizona jurisdictions that utilize the Pima County Medical Examiner to investigate their unnatural deaths. Because of the utterly dangerous nature of trekking across the Sonoran Desert, especially in the summer months, many of these unfortunate migrants succumb to the effects of heat-related illness and perish along the journey. The combined effects of a dry, hot environment and the remoteness of some of the trekking corridors can quickly render a deceased person unidentifiable by visual means. Thus, our office is faced with not only an increase in the number of deaths requiring medico-legal investigation but also an increase in the number of decedents needing additional specialized examinations in an effort to effect identification. This paper attempts to outline the problems and the methods utilized by our office over the past 6 years in the identification process of undocumented border crossers. It is hoped that this paper, as well as the others presented at this symposium, will allow for the sharing of information amongst all medical investigators who assist in the identification of these migrants. The identification of these individuals takes on added importance when one considers the possible nationalities, and perhaps motivation for entering into the US, of those that remain unidentified.     

A survey of background levels of explosives and related compounds in the environment

In this paper, swabbings from various public areas in 28 different cities throughout the United States were collected. A wide variety of objects were tested, ranging from park benches and telephones to sign posts and mailboxes. Inorganic anions and cations common in low explosives were detected simultaneously using capillary zone electrophoresis. Organic high explosives including nitroaromatics, nitramines, and nitrate esters were detected using gas chromatography with a pulsed-discharge electron capture detector. Confirmation of selected results was performed by ion chromatography and negative ion chemical ionization GC/MS. In general the results provide two major conclusions: (i) with the exception of nitrate, most low explosive oxidizers are rare in the environment; (ii) no organic explosives or significant interferences to these explosives were detected.     

Identifying Southwest Hispanics using nonmetric traits and the cultural profile

Due to the increasing number of Southwest Hispanics in the United States, as well as the overwhelming number of foreign nationals that die every year trying to enter the United States along the southern United States border with Mexico, new methods for classifying individuals have been established at the Pima County Office of the Medical Examiner in Tucson, Arizona (PCOME). For each of the past 5 years, the PCOME has investigated a record number of deaths associated with these border crossings. The overwhelming majority of the identified decedents are Mexican Nationals. However, approximately 25% of these undocumented border crossers have yet to be identified, making it clear that improved methods for human identification are greatly needed. The first goal of this paper is to delineate the suite of skeletal nonmetric traits utilized in assessing Southwest Hispanic ancestry at the PCOME. This suite of nonmetric traits has proven to be an effective component in establishing the "biological profile" of unknown individuals in these cases. The second goal of this paper is to introduce methods used at the PCOME to establish the "cultural profile" of individuals in these cases. The "cultural profile" is a set of identification criteria that include: the geographic context of recovery, personal effects, dental health, and cultural accoutrements. Establishing the "cultural profile" in these cases is essential in identifying individuals as foreign nationals who have died trying to cross the border.     

Evaluation and quantification of nuclear DNA from human telogen hairs

Nuclear DNA was extracted from human telogen hairs from 60 individuals. Six to nine hairs from each individual were individually extracted. The amount of DNA recovered from each individual varied greatly, and most samples yielded a quantity of 550 pg or less per hair. A selective extraction buffer was used to remove epithelial cell DNA and the amount of exogenous DNA was determined. DNA was also quantified by real time PCR using three different sized amplicons targeting an Alu sequence. The results were used to determine the state of degradation of the extracted DNA. Different quantities of sample (<100 pg, 100-500 pg, >500 pg) were amplified with the Miniplex kits to determine the minimum DNA template required for successful amplification. DNA recovered from hair showed degradation; however, partial profiles were obtained for those samples containing at least 60 pg using MiniSTRs.     

Interdisciplinary evaluations for guardianships and conservatorships

The adequacy of forensic evaluations by an individual expert representing one discipline has increasingly been questioned. A growing awareness has developed that such evaluations can best be conducted by an interdisciplinary team of health-related professionals pooling their respective expertises. Nevertheless, a review of state laws pertaining to evaluations in connection with guardianship and/or conservatorship proceedings show that in most states little provision is made for the utilization of such interdisciplinary teams. In light of the grave risks resulting from an inappropriate evaluation in these proceedings. support is given to a model guardianship and conservatorship statute proposed by the Developmental Disabilities State Legislative Project of the American Bar Association's Commission on the Mentally Disabled which incorporates an interdisciplinary approach for such evaluations (Sales, Powell, Van Duizend, and Associates, 1982).