905 research outputs found
Metal chelation therapy and Parkinson’s disease: A critical review on the thermodynamics of complex formation between relevant metal ions and promising or established drugs
No full textThe present review reports a list of approximately 800 compounds which have been
used, tested or proposed for Parkinson’s disease (PD) therapy in the year range 2014–2019 (April):
name(s), chemical structure and references are given. Among these compounds, approximately 250
have possible or established metal-chelating properties towards Cu(II), Cu(I), Fe(III), Fe(II), Mn(II),
and Zn(II), which are considered to be involved in metal dyshomeostasis during PD. Speciation
information regarding the complexes formed by these ions and the 250 compounds has been collected
or, if not experimentally available, has been estimated from similar molecules. Stoichiometries and
stability constants of the complexes have been reported; values of the cologarithm of the concentration
of free metal ion at equilibrium (pM), and of the dissociation constant Kd (both computed at pH = 7.4
and at total metal and ligand concentrations of 106 and 105 mol/L, respectively), charge and
stoichiometry of the most abundant metal–ligand complexes existing at physiological conditions,
have been obtained. A rigorous definition of the reported amounts is given, the possible usefulness
of this data is described, and the need to characterize the metal–ligand speciation of PD drugs
is underlined
Revisiting Lead(II)-1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic Acid Coordination Chemistry in Aqueous Solutions: Evidence of an Underestimated Thermodynamic Stability
No full textThe complexes formed between Pb2+ and 1,4,7,10-tetraazacyclododecane-1,4,7,10-tetraacetic acid (DOTA) were reinvestigated in aqueous solutions using a combination of pH potentiometry, UV-vis spectroscopy, and NMR spectroscopy. The thermodynamic data were supported by kinetics assays. Differently protonated complexes, i.e., [PbH3L]+, [PbH2L], [PbHL]-, and [PbL]2-, were detected, and the corresponding stability constants (logβ) at T = 298 K and I = 0.1 M NaCl were 33.1 ± 0.2, 32.00 ± 0.06, 29.28 ± 0.06, and 25.3 ± 0.1, respectively. Results differed significantly from those previously reported by Chaves et al. (Talanta 1992, 39, 249) and Pippin et al. (Inorg. Chim. Acta 1995, 239, 43) in both the speciation and the overall complex stability; the latter in particular was found to be remarkably higher. The work disclosed herein provides revised data on the Pb2+-DOTA complexes, which should be used as a new stability benchmark during the development of lead chelators
Power supply quality improvement by short-circuit current limitation on distribution nets
No full textCannabis and cognition: connecting the dots towards the understanding of the relationship
No full textSeveral studies have advanced the understanding of the effects of cannabis on cognitive function. A comprehensive reappraisal of such literature may help in drawing conclusions about the potential risks associated with cannabis use. In summary, the evidence suggests that earlier age of use, high-frequency and high-potency cannabis use, as well as sustained use over time and use of synthetic cannabinoids, are all correlated with a higher likelihood of developing potentially severe and persistent executive function impairments. While the exact mechanisms underlying the adverse effects of cannabis on cognition are not completely clear, Magnetic Resonance Imaging (MRI) studies support the presence of both structural and functional alterations associated with cannabis use. Cognitive dysfunction is also a core feature of many neuropsychiatric disorders and care must be taken regarding the effects of cannabis use in these patient populations. Cognitive impairments affect patients' daily functions, sociability, and long-term outcome, posing elevated economic, social, and clinical burdens. There is, thus, a compelling case for implementing behavioral and cognitive rehabilitation therapies for these patients, as well as investigating the endocannabinoid system in the development of new psychopharmacological treatments
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