SUMMARY1. In human blood, heroin is rapidly hydrolysed by sequential deacylation of two ester bonds to yield first 6-monoacetylmorphine (6-MAM), then morphine.2. Serum butyrylcholinesterase (BuChE) hydrolyses heroin to 6-MAM with a catalytic efficiency of 4.5/min per mol/L, but does not proceed to produce morphine.3. In vitro, human erythrocyte acetylcholinesterase (AChE) hydrolyses heroin to 6-MAM, with a catalytic efficiency of 0.5/min per mol/L under first-order kinetics. Moreover, erythrocyte AChE, but not BuChE is capable of further hydrolysing 6-MAM to morphine, albeit at a considerably slower rate.4. Both hydrolysis steps by erythrocyte AChE were totally blocked by the selective AChE inhibitor BW284c51 but were not blocked by the BuChE-specific inhibitor, iso-OMPA (tetraisopropylpyrophosphoramide).5. The brain synaptic form of AChE, which differs from the erythrocyte enzyme in its C-terminus, was incapable of hydrolysing heroin.6. Heroin suppressed substrate hydrolysis by antibodyimmobilized erythrocyte but not by brain AChE.7. These findings reveal a new metabolic role for erythrocyte AChE, the biological function of which is as yet unexplained, and demonstrate distinct biochemical properties for the two AChE variants, which were previously considered catalytically indistinguishable.
Quantitative data are reported for the first time on the amounts of iron, which are transferred to the hand upon holding a firearm. Iron levels between 21–315 ng/cm2 were found on volunteers' palms after a single holding of a handgun. Determination of the iron traces was accomplished spectrophotometrically using 3-(2-pyridyl)-5, 6-diphenyl-1,2,4-triazine (PDT) as a complexing agent. The transfer of iron from firearms to the palm was found to be, by and large a chemical (dissolution) rather than mechanical dislodgement. The prime factor that determines the amount of iron transferred from the firearm to the hand is the moisture level on the palm. These findings are likely to be of importance in courts of law, as well as in the war against terrorism and serious crime.
Various factors governing the detectability of explosive traces after being soaked in water were studied. The variables are: the type of the surface (surfaces liable to be found in aircraft were chosen), the type of explosive, the type of water (tap or seawater), and movement of the immersed surface in the water. The maximal immersion times (tmax) after which explosive detection was possible were evaluated. This datum was found to depend on the type of explosive (one of the important factors is solubility in water), the surface material and the environmental conditions (tap or seawater movement). Detection of PETN on high-density polyethylene, linoleum, glass and aluminum, by the chemical Explosive Testing Kit (ETK), was possible even after a month of soaking in seawater. In addition, it has been found that movement of bulk water around the samples with deposited explosives considerably decreases tmax values. It is, therefore, recommended to retrieve samples for explosive analysis as soon as possible and in areas where the currents of water is minimal.
Pyridyldiphenyl triazine (PDT) and three of its analogues were compared as practical reagents for visualizing unseen impressions left on the hands of a person who has held a firearm. The parent compound, PDT, gave the best results using intensity and clarity as measuring criteria. The effectiveness of the PDT reaction was then studied on 147 volunteers who had held firearms in their hands. Identifiable impressions of the metallic parts of the weapons were developed on the hands of 103 volunteers (70%). Results with females were slightly higher than with males, however, the difference was possibly statistically insignificant, and needs further study. Ferroprint™ and Ferrotrace™,5 commercial preparations that are based on the PDT reaction, have become a part of the professional equipment of every crime scene technician in Israel.
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