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Biomedical subjects

J M Curran

Publications and source records attributed to J M Curran.

9 recordsLinked to original sources

Genetic matches and the logic of the law.

In a recent article Levine and Kobilinsky (1997) point out that current methods in forensic DNA 'identification' are inadequate because the commercial kits commonly used in forensic practice do not detect the true genotype, but rather a genotype based on convenient categorization. For this reason, Levine and Kobilinsky argue that statistics attached to such categorizations are invalid. The authors believe that the arguments of Levine and Kobilinsky are logically flawed.

Criminal Law↗

Interpreting DNA mixtures in structured populations.

DNA profiles from multiple-contributor samples are interpreted by comparing the probabilities of the profiles under alternative propositions. The propositions may specify some known contributors to the sample and may also specify a number of unknown contributors. The probability of the alleles carried by the set of people, known or unknown, depends on the allelic frequencies and also upon any relationships among the people. Membership of the same subpopulation implies a relationship from a shared evolutionary history, and this effect has been incorporated into the probabilities. This acknowledgment of the effects of population structure requires account to be taken of all people in a subpopulation who are typed, whether or not they contributed to the sample.

Alleles↗

Combining a continuous Bayesian approach with grouping information.

When someone breaks glass a number of tiny fragments may be transferred to that person. If the glass is broken in the commission of a crime then these fragments may be used as evidence. A Bayesian interpretation of this evidence relies on, among other things, the forensic scientist's ability to assess the likelihood that the glass recovered from the suspect may have come from more than one source. This paper will examine the effect of including this information in the interpretation. We envisage working towards a system whereby the information loss that occurs during the normal casework activities of sample selection and glass fragment grouping is quantified.

Algorithms↗

A screening test for subclinical liver disease in horses affected by pyrrolizidine alkaloid toxicosis.

OBJECTIVE: To evaluate various biochemical tests as indicators of subclinical liver disease in horses exposed to pyrrolizidine alkaloid toxicosis. DESIGN: A clinical pathology field study. ANIMALS: Twenty-two clinically normal horses from four properties in the Kimberley region of Western Australia. PROCEDURE: Serum samples from each horse were assayed for gamma glutamyltransferase, alkaline phosphatase and aspartate aminotransferase activities, and for serum bile acid concentration, albumin and total protein. Serum protein electrophoresis was performed and their amino acid profiles determined. Bromosulphophthalein half-clearance times were measured. Horses were then subjected to a single liver biopsy. Results were analysed by, variance of group means, the Fisher-Irwin exact test, and by sensitivity and specificity calculation. RESULTS: Horses were classified into 2 groups, of 10 unaffected and 12 subclinically affected, on the basis of liver histology. Significant differences between the unaffected and subclinical groups were observed for gamma glutamyltransferase and alkaline phosphatase activities (P < 0.01). Gamma glutamyltransferase had sufficient sensitivity (75%) and specificity (90%) to function as a primary screening test for subclinical liver disease in horses exposed to pyrrolizidine alkaloids. Alkaline phosphatase was useful, but with lower sensitivity (58%). CONCLUSION: Serum gamma glutamyltransferase activity is a useful screening test for detecting subclinical liver disease in horses exposed to pyrrolizidine alkaloids under field conditions in northern Australia.

Alkaline Phosphatase↗

Evaluating the statistical significance of single band profiles in VNTR analyses.

VNTR profiles may present either a single band or two bands. If two bands are present then the individual is a heterozygote for these two bands. However, if only one band is present there is ambiguity as to the true genotype of the individual. This person may be a homozygote in that he has two copies of the same allele, or he may be a heterozygote for two very close bands that cannot be separated on the gel. The second NRC report proposed the use of the '2p' rule, or Formula 4.10a in the sub-structure case, as a conservative upper bound in the statistical interpretation. However, further examination suggests that these formulae are not necessarily conservative. In this paper we examine this phenomenon by deriving a formula that contains both the corrections for null alleles and for subpopulation effects.

DNA Fingerprinting↗

Assessing transfer probabilities in a Bayesian interpretation of forensic glass evidence.

When someone breaks glass a number of tiny fragments may be transferred to that person. If the glass is broken in the commission of a crime then these fragments may be used as evidence. A Bayesian interpretation of this evidence relies on the forensic scientist's ability to assess the probability of transfer. This paper examines the problem of assessing this probability and suggests some solutions.

Bayes Theorem↗

Sampling in forensic comparison problems.

When someone breaks glass a number of tiny fragments may be transferred to that person. If the glass is broken in the commission of a crime then these fragments may be used as evidence. If a large number of fragments are recovered from the suspect, then it may be more efficient for the forensic scientist to examine a subset of these fragments. Such sampling incurs information loss. This paper will derive an expression that allows a partial quantification of this loss. The loss of such information due to the examination of a subset of recovered material arises with many forms of evidence.

Forensic Medicine↗