• Polymer(Korea)
• /
• v.27 no.4
• /
• pp.330-339
• /
• 2003

Three kinds of macro-reticular bead-typed chelating resins having thiol groups were obtained from basic resins like poly(strene-co-divinylbenzene) (PSD) and poly(styrene-co-methyl methacrylate-co-divinylbenzene) (PSMD): the chelating resin (I) was prepared by chloromethylation of phenyl rings of PSD followed by thiolation using thiourea. The chelating resin (ll) was designed to provide enough space to chelate heavy metal ions; one chloromethyl group was obtained by chlorination of hydroxymethyl group provided by reduction of carboxylic ester group of PSMD and another chloromethyl group was obtained by direct chloromethylation of pendent phenyl group using chloromethyl methyl ether. Both of chloromethyl groups were thiolated by using thiourea. The chelating resin (III) was prepared by chlorosulfonation of phenyl rings of PSD followed by thiolation using sodium hydrosulfide. The adsorbtivity toward heavy metal ions was evaluated. The hydrophobic chelating resin (I) with thiol groups showed highly selective adsorption capacity f3r mercury ions. However, the chelating resin (II) with thiol groups showed mere effective adsorption capacity toward mercury ions than chelating resin (I) with thiol groups, and showed some adsorption capacity for other heavy metal ions like Cu$\^$2＋/, Pb$\^$2＋/, Cd$\^$2＋/ and Cr$\^$3＋/. On the other hand, the chelating resin (III) which have hydrophilic thiosulfonic acid groups was found to be effective adsorbents for some heavy metal ions such as Hg$\^$2＋/, Cu$\^$2＋/, Ni$\^$2＋/, Co$\^$2＋/, Cr$\^$3＋/ and especially Cd$\^$2＋/ and Pb$\^$2＋/.

• Journal of Life Science
• /
• v.18 no.11
• /
• pp.1485-1492
• /
• 2008

Prostaglandin $A_2$ ($PGA_2$), one of cyclopentenone PGs, induced both apoptosis and heme oxygenase (HO)-1 expression in U2OS cells. $PGA_2$-induced apoptosis was not perturbed by either over-expression or knock-down of HO-1, whereas $H_2O_2$-induced cell death was inversely modulated by the expression level of HO-1. In addition, N-acetyl-L-cysteine (NAC), a thiol antioxidant, blocked both apoptosis and HO-1 expression induced by $PGA_2$. But, non-thiol antioxidants like butylated hydorxyanisole (BHA) and ascorbic acid did not block either apoptosis or HO-1-induction. Taken together, these results suggest that $PGA_2$ induces both apoptosis and HO-1 expression, which are critically related to the thiol- reactivity of $PGA_2$, but not oxidative stress, and HO-1 expression may be independent or functionally located downstream of apoptosis by $PGA_2$ without contribution to apoptosis progression.

• Proceedings of the Korean Society of Toxicology Conference
• /
• 2002.05a
• /
• pp.93-93
• /
• 2002

Oxidative stress has been associated with a number of diseases in humans. Among the sources that can generate oxidative stress, it has been reported that iron can generate reactive oxygen species (ROS) with thiol. In iron overload state, increased thiol levels in plasma appeared to be associated with human mortality.(omitted)

• Analytical Science and Technology
• /
• v.8 no.3
• /
• pp.383-389
• /
• 1995

A new approach for the measurement of the surface coverages of monomolecular films fabricated by spontaneous adsorption of thiol compounds on gold is described. It is based on the mass change measurement with EQCM for the reductive electrochemical desorption of thiol in aqueous KOH solution. The results were compared with that of charge calculation during electrochemical desorption. The surface coverage value for eicosanethiol agrees with that obtained by charge calculation of electrochemical reduction as well as that expected from a geometrical model of the compact monolayer.

• Bulletin of the Korean Chemical Society
• /
• v.24 no.10
• /
• pp.1512-1514
• /
• 2003

• Proceedings of the Korean Biophysical Society Conference
• /
• 1997.07a
• /
• pp.15-15
• /
• 1997

Recent studies indicate that hydrogen peroxide (H$_2$O$_2$), which is one of the reactive oxygen species involved in the oxidative stress, is an intracellular secondary messenger in the signal transduction. A novel family of thiol specific antioxidant (TSA) enzymes with a peroxidase activity shows no sequence homology to previously known antioxidant enzymes.(omitted)

• Toxicological Research
• /
• v.32 no.2
• /
• pp.133-140
• /
• 2016

Sulfasalzine is a widely administered drug against inflammatory-based disorders in human. However several cases of liver injury are associated with its administration. There is no stabilized safe protective agent against sulfasalazine-induced liver injury. Current investigation was designed to evaluate if N-acetylcysteine (NAC) and dithioteritol (DTT) as thiol reducing agents and/or vitamins C and E as antioxidants have any protective effects against sulfasalazine-induced hepatic injury in an ex vivo model of isolated rat liver. Rat liver was canulated and perfused via portal vein in a closed recirculating system. Different concentrations of sulfasalazine and/or thiol reductants and antioxidants were administered and markers of organ injury were monitored at different time intervals. It was found that 5 mM of sulfasalazine caused marked liver injury as judged by rise in liver perfusate level of alanine aminotransferase (ALT), aspartate aminotransferase (AST), and lactate dehydrogenase (LDH) (p < 0.05). A significant amount of lipid peroxidation and hepatic glutathione depletion were detected in drug-treated livers, accompanied with significant histopathological changes of the organ. Administration of NAC ($500{\mu}M$), DTT (${400\mu}M$), Vitamin C ($200{\mu}M$), or vitamin E ($200{\mu}M$) significantly alleviated sulfasalazine-induced hepatic injury in isolated perfused rat liver. The data obtained from current investigation indicate potential therapeutic properties of thiol reductants and antioxidants against sulfasalazine-induced liver injury.

• Journal of Microbiology and Biotechnology
• /
• v.23 no.5
• /
• pp.699-706
• /
• 2013

We have previously reported that N-acetylcysteine (NAC) not only delayed apoptosis but also enhanced the production of recombinant erythropoietin (EPO) in Chinese hamster ovary (CHO) cell culture. To investigate the production enhancement mechanism, the effects of similar thiol-reducing agents were studied. Intriguingly, all mild reducing agents examined including mercaptoethanesulfonic acid (MESNA), thiolactic acid (TLA), and thioglycolate (TG) were shown to block apoptosis and increase EPO production. A pulse-chase study of EPO secretion revealed that all four thiol-reducing agents increased the EPO secretion rate; among them TLA showed the highest rate. In terms of product quality, the sialic acid content of the glycoprotein is one of the most important factors. It was reported that a number of glycoproteins produced by CHO cells often have incomplete sialylation, particularly under high-producing conditions. Human ${\alpha}2,3$-sialyltransferase (${\alpha}2,3$-ST) was introduced into EPO-producing CHO cells in order to compensate for the reduced sialylation during supplementation with NAC. When ${\alpha}2,3$-ST was expressed in the presence of NAC, reduced sialylation was restored and an even more sialylated EPO was produced. Thus, our study is significant in that it offers increased EPO production while still allowing the prevention of decreased sialylation of EPO.

• Polymer(Korea)
• /
• v.34 no.5
• /
• pp.469-473
• /
• 2010

The curing mechanism and characteristics of UV curable acrylate resins were studied using Photo-DSC, FTIR, and Raman spectroscopy. Effects of chemical structures of acrylate, numbers of functional group, and UV intensity on curing kinetics were investigated with Photo-DSC. FTIR and Raman spectroscopy has been used to understand curing mechanisms and reaction conversion. In order to investigate the effect of oxygen on the photo-curing reaction, the curing process was compared between the acrylate and thiol-ene resins. The reaction conversion was found to be less than 80% for acrylate resins. The photo-curing reaction of the acrylate resin could not proceed to the end because of oxygen which acts as a reaction inhibitor while the thiol-ene resin was hardly affected from oxygen during the curing process.

• Korean Chemical Engineering Research
• /
• v.46 no.6
• /
• pp.1069-1074
• /
• 2008

In this work, we made a study for the 3D SAM formation of octanethiol, decanethiol, and dodecanethiol on copper nanoparticles and we verified stability of the copper particle depending on the ratio of dodecanethiol to copper. The reaction was performed in a one-phase system under nitrogen atmosphere and the thiolated copper particles could be obtained by centrifugation. We could confirm that the nanoparticles consisted of a spherical shape of 3~6 nm from TEM images. FT-IR, XPS and TGA results showed that alkanethiols were chemisorbed via thiol group and the packing density of the alkanethiols on copper surface increased with the alkyl chain lengths. XRD patterns gave us useful information about superlattice formations. Finally, $Cu_2O$ was formed when the molar ratio of dodecanethiol to copper is less than unity and copper nanoparticles formed more compact 3D SAMs when the molar ratio of dodecanethiol to copper was 1.25.