The aim of this study was to investigate the effect of acid challenge on the activation of matrix metalloproteinases (MMPs) in the Dentinoenamel junction of primary and permanent teeth submitted to radiotherapy. For this purpose, a total of 178 dental fragments obtained from molars were used, and randomly divided into 2 groups (primary and permanent teeth) / 4 experimental subgroups (irradiated and non-irradiated, demineralized and non-demineralized). The fragments were exposed to radiation, with a dose fraction of 2 Gy, for 5 consecutive days, until a total dose of 60 Gy was reached, with a total of 30 cycles, for 6 weeks. To determine the activity of MMPs on the dentinoenamel junction (DEJ), in situ zymography assays on 0.6mm dental fragments were performed. To assess whether MMP activity would be impacted by an acidic environment, the fragments were placed in a demineralizing solution (pH of 4.8). The finding was that irradiation activated MMPs in DEJ and these effects were more evident in permanent when compared with primary teeth. When the effect of an acid challenge on MMPs activity was investigated, demineralization was observed not to increase MMPs activity in non-irradiated teeth, but it did increase MMPs activity in irradiated teeth. In conclusion, an acid challenge was found to exacerbate activation of MMPs in DEJ of permanent teeth submitted to irradiation, but not in primary teeth.
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http://dx.doi.org/10.1590/1807-3107bor-2024.vol38.0034 | DOI Listing |
New Phytol
January 2025
Université de Lorraine, INRAE, LAE, 54000, Nancy, France.
Specialized metabolites are molecules involved in plants' interaction with their environment. Elucidating their biosynthetic pathways is a challenging but rewarding task, leading to societal applications and ecological insights. Furanocoumarins emerged multiple times in Angiosperms, raising the question of how different enzymes evolved into catalyzing identical reactions.
View Article and Find Full Text PDFDiscov Nano
January 2025
Particle Engineering Centre, Department of Chemical Engineering, Norwegian University of Science and Technology, Trondheim, 7491, Norway.
The increasing demand for magnetic iron oxide nanoparticles (IONPs) in biomedicine necessitates efficient and scalable production methods. Thermal decomposition offers excellent tailoring of the particle properties but its discontinuous batch-operation is restricting scale-up and industrial application. To overcome these challenges, several studies have demonstrated semi-continuous thermal decomposition by slowly injecting the precursor, though only half of them produce magnetite IONPs and even fewer use iron oleate precursors.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
Western University, Chemistry, 1151 Richmond Street, N6A3K7, London, CANADA.
This work addresses fundamental questions that deepen our understanding of secondary coordination sphere effects on carbon dioxide (CO2) reduction using derivatized hydride analogues of the type, [Cp*Fe(diphosphine)H] (Cp* = C5Me5-) - a well-studied family of organometallic complex - as models. More precisely, we describe the general reactivity of [(Cp*-BR2)Fe(diphosphine)H], which contains an intramolecularly positioned Lewis acid, and its cooperative reactivity with CO2. Control experiments underscore the critical nature of borane incorporation for CO2 to reduced products, a reaction that does not occur for unfunctionalized [Cp*Fe(diphosphine)H]).
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
New York University, Chemistry, 29 Washington Place, RM 10001, 10003, New York, UNITED STATES OF AMERICA.
Herein, we report a Lewis acid-mediated ring expansion of donor-acceptor cyclopropanes (DACs) to substituted azetidines via nucleophilic nitrogen group transfer from readily accessible iminoiodinane. This protocol operates under mild, transition-metal-free conditions, and showcases excellent chemoselectivity, along with broad functional group tolerance. We report for the first time that challenging alkyl donor-acceptor cyclopropanes can undergo ring expansion leading to aliphatic azetidines without relying on external oxidants or precious transition-metal catalysts.
View Article and Find Full Text PDFAngew Chem Int Ed Engl
January 2025
University of California, San Diego, Chemistry and Biochemistry, 9500 Gilman Drive, Urey Hall 4120, 92093, La Jolla, UNITED STATES OF AMERICA.
Membrane-forming phospholipids are generated in cells by enzymatic diacylation of non-amphiphilic polar head groups. Analogous non-enzymatic processes may have been relevant at the origin of life and could have practical utility in membrane synthesis. However, aqueous head group diacylation is challenging in the absence of enzymes.
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