Research and Publications
The Toxicology Unit is carring out internationally recognised research in the field of forensic toxicology.
Below are our Current research projects or see our completed research projects.
Current research
Cannabinoids in hair
Three cannabinoids are routinely looked for in hair, cannabinol (CBN), cannabidiol (CBD) and delta 9-tetrahydrocannabinol (THC). These drugs are present in smoke and can be absorbed in to hair from the smoke. This means that a person can have these compounds present in their hair just from being present in the room where cannabis smoking is taking place. Using hair, in order to prove that cannabis has actually been ingested, the metabolite carboxy-tetrahydrocannabinol (THC-COOH) has to be detected.
The vast majority of people who carry out analysis of hair for cannabinoids are analysing for CBN, CBD and THC only; they are not analysing for THC-COOH. It has been demonstrated that the technique of choice for detection of THC-COOH in hair is 2D GC-MS. The Toxicology Unit uses this technique and is developing a method for the simultaneous assay of CBN, CBD, THC and THC-COOH in hair.
Distribution of β-hydroxybutyrate and related parameters in post-mortem cases as markers to distinguish between diabetic and alcoholic ketoacidosis
Diabetic ketoacidosis (DKA) is concomitant with severe hyperglycemia due to increased glucose production and impaired peripheral glucose use caused by insulin deficiency. Alcoholic ketoacidosis (AKA) is associated with a history of chronic alcohol abuse and decreased food intake. It presents normal or low blood glucose concentration due to prolonged starvation with hepatic glycogen depletion and impaired gluconeogenesis caused by decreased nicotinamide adenosine dinucleotide (NAD+).
Typical markers for ketoacidosis are increased concentrations of β-hydroxybutyrate (β-HB) and acetone in the blood. Traditionally acetone only has been analysed for as this can be measured simultaneously with ethanol; ethanol measurement is carried out on virtually every case submitted by HM Coroners. It has been suggested that β-HB is a preferable marker for AKA as it has a stronger relationship with the NADH/NAD+ ratio and accounts for two-thirds of all ketone bodies in healthy people. Pathologists are now increasingly asking for analysis for β-HB in addition to acetone in order to distinguish between AKA and DKA.
Glucose is not stable in post-mortem blood. The concentration of glucose in vitreous humor remains more stable after death and is thought to be equivalent to the blood glucose concentration. In some post-mortem cases vitreous humor is submitted for glucose analysis. A high glucose concentration is indicative of hyperglycaemia but a low value cannot be used to demonstrate hypoglycaemia because it could be due to glucose break-down.
The proposed study is investigating the suggestion that β-HB is a preferable marker for alcoholic ketoacidosis.
