Screening people for illicit substances: a survey of current portal technology.

The need to implement more effective, cost efficient, non-intrusive ways of screening people for concealed drugs, explosives and weapons is a major security initiative for the U.S. and elsewhere. A new generation of portals suitable for security checkpoints is under development. These will be able to find contraband with high probabilities of detection, and low false-alarm rates. Some portals image the body using either low dose X-rays or millimeter wave interrogation, and analyze the radiation back-scattered from the body, providing images of concealed objects. Other portals operate essentially as anomaly detectors, finding objects on the human body. A series of portals is also under development that can harvest and analyze vapors or particles of the contraband substances. Some of the issues surrounding portal development include perceived safety issues, privacy issues, and operational issues such as ease of operation, non-invasiveness, and ease of interpretation. It is believed that portal technology will mature, and the cost of portals will fall sufficiently to make widespread deployment of portals at security checkpoints a reality within the next decade.

Relative binding constants of arsenical-antidote adducts determined by NMR spectroscopy.

Proton nuclear magnetic resonance spectroscopy was used to determine relative binding constants for several arsenical-antidote adducts. It was found that BAL (2,3-dimercaptopropanol) and DMPS (2,3-dimercaptopropanesulfonic acid) had a higher affinity than DMSA (2,3-dimercaptosuccinic acid) for the two organic arsenicals studied.

Enzyme-amplified receptor assay screening test for chlorpromazine, trifluoperazine, and phencyclidine.

A new receptor based assay is described for the determination of classes of drugs which have high affinities for the acetylcholine receptor. The method is based upon the inhibition of the enzyme activity of an enzyme-drug conjugate by the binding to the receptor protein, and competition between free drugs and the enzyme-drug conjugate for a limited number of receptor sites. The activity of the enzyme marker system, glucose-6-phosphate dehydrogenase covalently conjugated to desipramine, is monitored by colorimetric detection of the rate of NADH formation at 340 nM. The procedure proposed is designed to provide a simple drug screen which can be done in a minimally equipped laboratory while achieving the required sensitivity. The technique is illustrated for three acetylcholine channel binding compounds: the hallucinogen phencyclidine (PCP) and the antipsychotic agents chlorpromazine and trifluoperazine. This procedure yields calibration curves with detection limits at nanomolar levels of drug, with binding responses dependent on the amounts of receptor and enzyme-labeled drug used. Aspecific binding responses of unlabeled enzyme to drug or receptor to compounds with low affinity for the receptor are shown to have minimal effect on the assay.

Reaction of trans-2-chlorovinylarsine oxide with polydeoxynucleotides.

Trans-2-chlorovinylarsine oxide (in DCl/acetone-d6) was added to various polydeoxynucleotides. The arsenical did react with poly[dG].poly[dC], releasing guanine, and resulting in a partial apurinic duplex.