Raman chemical imaging spectroscopy reagentless detection and identification of pathogens: signature development and evaluation.

An optical detection method, Raman chemical imaging spectroscopy (RCIS), is reported, which combines Raman spectroscopy, fluorescence spectroscopy, and digital imaging. Using this method, trace levels of biothreat organisms are detected in the presence of complex environmental backgrounds without the use of amplification or enhancement techniques. RCIS is reliant upon the use of Raman signatures and automated recognition algorithms to perform species-level identification.

Levels of 4-hydroxynonenal and malondialdehyde are increased in brain of human chronic users of methamphetamine.

Animal studies suggest that the widely used psychostimulant drug methamphetamine (MA) can harm brain dopamine neurones, possibly by causing oxidative damage. However, evidence of oxidative damage in brain of human MA users is lacking. We tested the hypothesis that levels of two "gold standard" products generated from lipid peroxidation, 4-hydroxynonenal (one of the most reactive lipid peroxidation aldehyde products) and malondialdehyde, would be elevated in post mortem brain of 16 dopamine-deficient chronic MA users compared with those in 21 matched control subjects.

Infrared and Raman microspectroscopy of foreign materials in tissue specimens.

Infrared and Raman spectra of materials found in tissue specimens submitted for histopathologic diagnosis have been recorded. These foreign materials range in size from approximately 5 to 50 microm, and the vibrational spectra have been used to identify them. Examples include cholesterol and polytetrafluoroethylene (PTFE) in an implant case, polyethylene terephthalate (PET) and polyacrylonitrile (PAN) in a pilonidal cyst, and carbenicillin in a skin biopsy.

Use of MDA (the "love drug") and methamphetamine in Toronto by unsuspecting users of ecstasy (MDMA).

It has recently been reported that purity of illicit tablets of ecstasy (MDMA) is now high. Our objective was to confirm whether hair of drug users, who request only ecstasy from their supplier, contains MDMA in the absence of other drugs. GC-MS analysis of scalp hair segments disclosed the presence of MDMA in 19 of 21 subjects and amphetamine/methamphetamine in eight subjects.

Brain antioxidant systems in human methamphetamine users.

Animal data suggest that the widely abused psychostimulant methamphetamine can damage brain dopamine neurones by causing dopamine-dependent oxidative stress; however, the relevance to human methamphetamine users is unclear. We measured levels of key antioxidant defences [reduced (GSH) and oxidized (GSSG) glutathione, six major GSH system enzymes, copper-zinc superoxide dismutase (CuZnSOD), uric acid] that are often altered after exposure to oxidative stress, in autopsied brain of human methamphetamine users and matched controls. Changes in the total (n = 20) methamphetamine group were limited to the dopamine-rich caudate (the striatal subdivision with the most severe dopamine loss) in which only activity of CuZnSOD (+ 14%) and GSSG levels (+ 58%) were changed.

Brain vesicular acetylcholine transporter in human users of drugs of abuse.

Limited animal data suggest that the dopaminergic neurotoxin methamphetamine is not toxic to brain (striatal) cholinergic neurons. However, we previously reported that activity of choline acetyltransferase (ChAT), the cholinergic marker synthetic enzyme, can be very low in brain of some human high-dose methamphetamine users. We measured, by quantitative immunoblotting, concentrations of a second cholinergic marker, the vesicular acetylcholine transporter (VAChT), considered to be a "stable" marker of cholinergic neurons, in autopsied brain (caudate, hippocampus) of chronic users of methamphetamine and, for comparison, in brain of users of cocaine, heroin, and matched controls.

Why is parkinsonism not a feature of human methamphetamine users?

For more than 50 years, methamphetamine has been a widely used stimulant drug taken to maintain wakefulness and performance and, in high doses, to cause intense euphoria. Animal studies show that methamphetamine can cause short-term and even persistent depletion of brain levels of the neurotransmitter dopamine. However, the clinical features of Parkinson's disease, a dopamine deficiency disorder of the brain, do not appear to be characteristic of human methamphetamine users.

Decreased striatal dopamine D1 receptor-stimulated adenylyl cyclase activity in human methamphetamine users.

Objective: It has been assumed that some behavioral changes associated with repeated exposure to dopaminergic psychostimulant drugs might be explained by changes in activity of dopamine receptors, including the dopamine D(1) receptor, which is linked by a stimulatory G protein to the effector enzyme adenylyl cyclase. To establish whether dopamine D(1) receptor function might be altered in human methamphetamine users, the authors measured dopamine-stimulated adenylyl cyclase activity in the brain of chronic human users of the drug.

Method: Adenylyl cyclase activity stimulated by dopamine and by guanylyl-imidodiphosphate (to assess G protein and adenylyl cyclase coupling) was determined in the postmortem brain tissue of 16 methamphetamine users who had used the drug both recently and chronically (i.

Cyclooxygenase inhibitor modulation of dopamine-related behaviours.

The sequential action of phospholipase A(2) and cyclooxygenase leads to the production of prostaglandins in the brain, an event hypothesised to cause dopaminergic stimulation. To investigate this further, we examined the effect of the nonselective cyclooxygenase inhibitors indomethacin and piroxicam on several indices of dopaminergic function in adult male rats. Both drugs inhibited catalepsy induced by the dopamine D1-like receptor antagonist R(+)-7-chloro-8-hydroxy-3-methyl-1-phenyl-2,3,4,5-tetrahydro-1H-3-benzazepine (SCH23390), the dopamine D2-like receptor antagonist raclopride and by haloperidol, findings in agreement with a dopaminergic effect of cyclooxygenase inhibitors.

Decreased activity of brain phospholipid metabolic enzymes in human users of cocaine and methamphetamine.

Phospholipids are essential components of cell membranes which may also function to mediate some of the behavioural effects of dopamine receptor stimulation caused by psychostimulant drugs. Neuroimaging and pharmacological data suggest that abnormal brain metabolism of phospholipids might explain some of the consequences of chronic exposure to drugs of abuse including drug craving. We previously reported decreased activity of calcium-stimulated phospholipase A(2) (Ca-PLA(2)) in autopsied putamen of human cocaine users.