A series of 3-amino-2-phenylpropene (APP) derivatives have been synthesized and characterized as novel competitive inhibitors, with K(i) values in the microM range, for the bovine chromaffin granule membrane monoamine transporter(s) (bVMAT). Although, these inhibitors are structurally similar to the bVMAT substrate tyramine, none of them were measurably transported into the granule. Structure-activity studies have revealed that, while the 3'- or 4'-OH groups on the aromatic ring enhance the inhibition potency, Me or OMe groups in these positions reduce the inhibition potency. Halogen substitution on the 4'-position of the aromatic ring causes gradual increase of the inhibition potency parallel to the electron donor ability of the halogen. Substituents on the NH(2) as well as on the 3-position of the alkyl chain reduce the inhibition potency. Comparative structure-activity analyses of APP derivatives with tyramine and the neurotoxin 1-methyl-4-phenylpyridinium suggest that the flexibility of the side chain and the relative orientation of the NH(2) group may be critical for the efficient transport of the substrate through the bVMAT. Comparable bVMAT affinities of these inhibitors to that of DA and other pharmacologically active amines suggest that they are suitable for the structure-activity and mechanistic studies of monoamine transporters and may also be useful in modeling the mechanism of action of amphetamine-related derivatives.

The active metabolite of 1-methyl-4-phenyl-1,2,3,6-tetrahydropyridine (MPTP), N-methyl-4-phenylpyridinium (MPP(+)), selectively destroys the dopaminergic neurons and induces the symptoms of Parkinson's disease. Inhibition of mitochondrial complex I and/or the perturbation of dopamine metabolism through cellular and granular accumulation have been proposed as some of the major causes of neurotoxicity. In the present study we have synthesized and characterized a number of MPTP and MPP(+) derivatives that are suitable for the comparative neurotoxicity and complex I inhibition versus dopamine metabolism perturbation studies. Structure-activity studies with bovine chromaffin granule ghosts show that 3'-hydroxy-MPP(+) is one of the best known substrates for the vesicular monoamine transporter (VMAT). A series of compounds that combine the structural features of MPP(+) and a previously characterized VMAT inhibitor, 3-amino-2-phenyl-propene, have been identified as the most effective VMAT inhibitors. These derivatives have been used to define the structural requirements of the VMAT substrate and inhibitor activities.

The present study is to point out the outcomes of the Seminar on the Chemical Weapon Convention and Chemical Safety and Security Management for Member States in the Asia Region held by Organization for the Prohibition of Chemical Weapons in Doha, Qatar, in February 2017. The seminar was aimed at supporting chemical safety and security (CSS) management in the chemical industry in Asian countries. Overall goal was to sensitize States Parties to the new approaches that can be adopted in relation to CSS management, with a particular focus on providing assistance to small and medium‐sized enterprises. This article reflects the observations made by keynote speakers via their interaction with participants from Asian State Parties during presentations' questions & answers sessions and following workshops. The article is an attempt to highlight the challenges in security risk assessment and management of chemical facilities and discuss some new trends for further improvements. © 2017 American Institute of Chemical Engineers Process Saf Prog 37: 211–220, 2018

We have recently characterized a series of 3-amino-2-phenylpropene (APP) derivatives as reversible inhibitors for the bovine adrenal chromaffin granule vesicular monoamine transporter (VMAT) that have been previously characterized as potent irreversible dopamine-␤-monooxygenase (D␤M) and monoamine oxidase (MAO) inhibitors. Halogen substitution on the 4Ј-position of the aromatic ring gradually increases VMAT inhibition potency from 4Ј-F to 4Ј-I, parallel to the hydrophobicity of the halogen. We show that these derivatives are taken up into both neuronal and non-neuronal cells, and into resealed chromaffin granule ghosts efficiently through passive diffusion. Uptake rates increased according to the hydrophobicity of the 4Ј-substituent. More importantly, these derivatives are highly toxic to human neuroblastoma SH-SY5Y but not toxic to M-1, Hep G2, or human embryonic kidney 293 non-neuronal cells at similar concentrations. They drastically perturb dopamine (DA) uptake and metabolism in SH-SY5Y cells under sublethal conditions and are able to deplete both vesicular and cytosolic catecholamines in a manner similar to that of amphetamines. In addition, 4Ј-IAPP treatment significantly increases intracellular reactive oxygen species (ROS) and decreases glutathione (GSH) levels in SH-SY5Y cells, and cell death is significantly attenuated by the common antioxidants ␣-tocopherol, N-acetyl-L-cysteine and GSH, but not by the nonspecific caspase inhibitor N-benzyloxycarbonyl-Val-Ala-Asp-fluoromethyl ketone. DNA fragmentation analysis further supports that cell death is probably due to a caspase-independent ROSmediated apoptotic pathway. Based on these and other findings, we propose that drastic perturbation of DA metabolism in SH-SY5Y cells by 4Ј-halo APP derivatives causes increased oxidative stress, leading to apoptotic cell death.Oxidative stress in the central and peripheral nervous systems plays a significant role in neurodegenerative disorders, aging, and the toxicity of a large number of neurotoxins (Cadet and Brannock, 1998;Halliwell, 2006). Auto-oxidizable catecholamines dopamine (DA), NE, and E and their metabolites are known to generate H 2 O 2 , reactive oxygen species (ROS), and organic radicals under aerobic conditions because of their intrinsic redox properties (Hald and Lotharius, 2005;Ogawa et al., 2005). Therefore, catecholaminergic neurons are inherently subjected to higher oxidative stress and more free radical damage than other types of neurons (Graham, 1978;Adams et al., 2001). Although most reactive radical species are effectively scavenged by enzymatic defense mechanisms and cellular antioxidants in vivo, excessive generation may lead to extensive cellular damage (Fridovich, 1986;Frei et al., 1989).Numerous studies indicate that efficient uptake, biosynthetic conversion, and storage of catecholamines in vesicles are mandatory for proper functioning of catecholaminergic neurons. The vital proteins responsible, including vesicular H ϩ -ATPase (V-H ϩ -ATPase), cytochrome b 561 (b 561 ), dopamine-␤...