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At least 19 recordsLinked to original sources
PubMed1999

Active oxygen species generation and cellular damage by additives of parenteral preparations: selenium and sulfhydryl compounds.

We investigated the relationship between active oxygen species (AOS) generation and cultured vascular endothelial cellular damage caused by simultaneous exposure to selenium compounds and sulfhydryl compounds such as cysteine (Cys) or reduced glutathione (GSH). Selenium compounds, selenite, selenate or selenomethionine (SeMet), are added to total parenteral nutrition (TPN) and intravenously administered. We confirmed by luminol dependent chemiluminescence, an indicator of AOS generation, that selenite generates AOS in the presence of clinical concentrations of sulfhydryl compounds, 0.5 mM Cys or 0.5 mM GSH, and that the amount of AOS generated reaches the maximum when their mole ratio is 1:50. However, AOS generation was not observed after simultaneous administration of various concentrations of selenate or SeMet with sulfhydryl compounds. Moreover, simultaneous exposure to 10 microM selenite and sulfhydryl compounds was found to result in significant increases in the [3H]-adenine and lactate dehydrogenase (LDH) release rates from cells, a significant decrease in the amount of cellular protein, and enhancement of cellular damage as compared with after exposure to selenite alone. However, simultaneous exposure to 10 microM selenate or 10 microM SeMet together with sulfhydryl compounds did not induce cellular damage. These findings revealed that selenite generates AOS and causes cellular damage in the presence of sulfhydryl compounds. Accordingly, it seems better to choose selenate or SeMet instead of selenite when a selenium compound is to be added to TPN.

Adenine↗
PubMed1992

Homocysteine and other sulfhydryl compounds enhance the binding of lipoprotein(a) to fibrin: a potential biochemical link between thrombosis, atherogenesis, and sulfhydryl compound metabolism.

We have previously shown that lipoprotein(a) [Lp(a)], an atherogenic lipoprotein that contains apolipoprotein(a), which shares partial structural homology to plasminogen, binds to a plasmin-modified fibrin surface, and we have postulated that this interaction may be atherogenic. Moderate elevations in blood homocysteine, a relatively common condition, predispose to premature atherosclerosis. The reasons for this are not established. We now report that homocysteine, at concentrations as low as 8 microM, significantly increases the affinity of Lp(a) for fibrin. Homocysteine induces a 20-fold increase in the affinity between Lp(a) and plasmin-treated fibrin and a 4-fold increase with unmodified fibrin. Lp(a) binding is inhibited by epsilon-aminocaproic acid, indicating lysine binding site specificity. Homocysteine does not enhance the binding of Lp(a) to other surface-bound proteins. Cysteine, glutathione, and N-acetylcysteine also increase the affinity between Lp(a) and fibrin. Homocysteine does not affect the binding of low density lipoprotein or plasminogen to fibrin, nor does it alter the gel-filtration elution pattern of Lp(a). Immunoblot analysis documents the fact that homocysteine partially reduces Lp(a). These results suggest that homocysteine alters the intact Lp(a) particle so as to increase the reactivity of the plasminogen-like apolipoprotein(a) portion of the molecule. The observation that sulfhydryl amino acids increase Lp(a) binding to fibrin suggests a biochemical relationship between sulfhydryl compound metabolism, thrombosis, and atherogenesis.

Blotting, Western↗
PubMed1991

The inhibition of metabolic oxalate production by sulfhydryl compounds.

A number of sulfhydryl compounds were shown to inhibit CO2 and oxalate formation from glyoxylate by rat liver homogenates and hepatocytes. The most significant inhibition occurred with cysteine and this inhibition was concentration-dependent. In rats made hyperoxaluric by administering ethylene glycol in their drinking water, daily intraperitoneal injections of cysteine caused a rapid and marked decrease in urinary oxalate excretion which was maintained over the duration of the treatment (28 days). Over this time period, the level of urinary oxalate excretion in these ethylene glycol-treated rats was reduced to that of the controls. It is postulated that the decrease is due to the formation of a cysteine-glyoxylate adduct, 2-carboxy-4-thiazolidine carboxylate, which prevents glyoxylate being further oxidized to oxalate. Cysteine or similar sulphydryl compounds may therefore have potential as therapeutic agents in the prevention of renal stones.

Aluminum↗
PubMed1987

False-positive results for ketone with the drug mesna and other free-sulfhydryl compounds.

All free-sulfhydryl compounds tested produced false-positive reactions in the Legal test for ketones. The color developed in the ketone pad of urine dipsticks [N-Multistix SG, Multistix 10 SG (Ames), and Chemstrip 9 (Boehringer-Mannheim)] was misinterpreted for ketone bodies, both by visual and automated reading. In contrast to the reaction with true ketones, a drop of glacial acetic acid added onto the ketone pad of dipsticks discharged the false-positive red color. A red-violet also developed instantly with free -SH compounds in the Acetest tablet assay (Ames), but quickly faded. In general, the presence of acidic groups such as -COOH and -SO3H in the structure appeared to increase the nitroprusside reactivity of free -SH compounds, whereas the presence of a -NH2 group appeared to decrease it. Currently, false-positive ketone reactions ascribable to a free -SH group are most likely to be seen for urine containing mesna. The false-positive test for ketones caused by free -SH compounds can be recognized and ruled out by proper procedures. On the other hand, this chromogenic reaction with free thiols might be used for monitoring urinary excretion of mesna.

False Positive Reactions↗
PubMed2003

Effects of sulfhydryl compounds on pancreatic cytoprotection in acute necrotic pancreatitis.

OBJECTIVE: To observe sulfhydryl compound variation in the injury of pancreatic cells and the effects of external sulfhydryl compounds on cytoprotection. METHODS: Male Wistar mice were divided randomly into three groups: groups A and B served as animal models (retrograde duct infusion with 5% sodium taurocholate), in group A, 45 animals were treated with normal saline therapy, in group B, 45 animals were treated with Tiopronin therapy; and group C, 15 animals, were designated as normal control. Animals were killed at 2, 4, 6, 12 and 24 h, and pancreatic tissue was analyzed for total sulfhydryl (TSH), nonprotein sulfhydryl (NPSH) and malondialdehyde (MDA). Histopathology, serum amylase (Sam) and C reactive protein (CRP) were assessed as well. RESULTS: Levels of Sam and CRP increased in both group A and group B, with corresponding pathological changes of acute nerotic pancreatitis (ANP). Levels of TSH, NPSH and protein sulfhydryl (PSH) in group A decreased markedly during pancreatitis (P < 0.01), but MDA increased significantly (P < 0.01). The depletion of NPSH in group B was markedly ameliorated at 4 h or 6 h, when Tiopronin was prophylactically administered (P < 0.05), after which the level of MDA showed very little increase when compared to group A (P < 0.01). Histopathological damage was attenuated to a certain extent, in regards to serum amylase and CRP. CONCLUSIONS: All sulfhydryl compounds decreased significantly during ANP; external sulfhydryl compound could protect the pancreatic cells most likely as a type of scavengers of oxygen free radicals, which are critically involved in the pathophysiology of ANP. Sulfhydryl plays an important role in the action of pancreatic cytoprotection.

Acute Disease↗
PubMed1984

Reactions of ferryl lactoperoxidase (compound II) with sulfide and sulfhydryl compounds.

Lactoperoxidase in the ferryl state (compound II) reacts with sulfide to form a typical sulfheme -containing hemoprotein as do hemoglobin, myoglobin, and catalase. Ferrous sulflactoperoxidase is primarily formed and then oxidized to its ferric form under aerobic conditions. Similar reactions of lactoperoxidase occurs when methylmercaptoimidazole (MMI) is substituted for sulfide. The yield of the adducts from one-turnover reactions of ferryl lactoperoxidase is 100% with sulfide and about 20% with MMI. Sulfur and MMI of the adducts appear to be removed from the enzyme upon reduction by dithionite. Upon the reactions with cysteine and dithiothreitol, the enzyme is converted to spectral species, which are less characteristic but are similar to ferrous and ferric sulflactoperoxidases , respectively. We conclude that there is no essential difference in the mechanism of reactions of lactoperoxidase with sulfide, MMI, cysteine, and dithiothreitol.

Animals↗
PubMed1988

Modulation of myoglobin-H2O2-mediated peroxidation reactions by sulfhydryl compounds.

The ability of specific low molecular weight sulfhydryl compounds to inhibit the myoglobin-H2O2 peroxidation of uric acid and arachidonic acid was investigated. alpha-Mercaptopropionyl glycine, N-acetylcysteine, and reduced glutathione inhibited both the oxymyoglobin and metmyoglobin H2O2-mediated peroxidation of uric acid in a dose-dependent manner. The IC50 for each drug ranged between 20 to 100 microM and was dependent on the presence of a reduced sulfhydryl group since neither oxidized glutathione nor methionine effectively blocked uric acid peroxidation. Similar inhibition of oxymyoglobin and metmyoglobin H2O2-mediated peroxidation of arachidonic acid was also observed with alpha-mercaptopropionyl glycine, reduced glutathione, and cysteine. Under conditions of this assay, the ferrous form of myoglobin and H2O2 produced approximately three times the amount of formaldehyde from dimethylsulfoxide than ferric myoglobin (metmyoglobin) and H2O2. However, metmyoglobin and H2O2 were more effective than either oxymyoglobin and deoxymyoglobin in mediating arachidonic acid peroxidation. Further, neither mannitol nor benzoic acid (known scavengers of .OH) effectively blocked myoglobin H2O2-induced peroxidation of either uric acid or arachidonic acid. Visible absorption spectra of oxymyoglobin and metmyoglobin after incubation with H2O2 indicates the formation of a relatively stable ferriperoxide derivative of myoglobin. The formation of the ferriperoxide myoglobin derivative was partially inhibited by the addition of reduced sulfhydryl compounds. These data are consistent with the hypothesis that during reperfusion injury of the ischemic myocardium, the phagocytic cell or intracellular-derived H2O2 may react with myoglobin and initiate peroxidation reactions independent of .OH formation leading to cell injury. The cardioprotective effects of alpha-mercaptopropionyl glycine and other sulfhydryl-containing compounds during reperfusion injury may be attributed, at least in part, to their ability to inhibit myoglobin-H2O2-mediated peroxidation reactions.

Arachidonic Acids↗
PubMed1994

Sulfhydryl compounds influence immunoreactivity, structure and functional aspects of lipoprotein(a).

Human plasma Lp(a) is susceptible to various sulfhydryl compounds. In this study we present evidence indicating that after treatment of Lp(a) with sulfhydryl compounds, immunoreactivity is changed, structural changes occur and functional characteristics regarding the numerous kringle structures in apo(a) disappear. Purified Lp(a) was subjected to variable concentrations (0.01-10 mM) of various sulfhydryl compounds: DTT, 2-mercapto-ethanol (BME), N-acetylcysteine (NAC) and homocysteine (HCys). Free SH groups were blocked by iodoacetamide. Reduced and alkylated Lp(a) was tested in two ELISAs, one detecting apo(a) alone and one detecting apo(a)-apoB complexes. In both ELISAs polyclonal antibodies were used. For comparison a commercial apo(a) IRMA utilizing two monoclonal antibodies was used. The results indicate that a similar decrease in response of both ELISAs is observed, whereas the IRMA response is less affected. Western blotting of "DTT treated" Lp(a) after SDS-PAGE under nonreducing conditions showed that separate apo(a) and apoB-100 bands became detectable at 1 mM DTT. Native PAGE (2.5-16%) indicated structural changes of Lp(a) beginning to occur at 0.03 mM DTT. Epsilon-aminocaproic acid-inhibitable binding of "DTT-treated" Lp(a) to Desafib-X decreased with increasing DTT concentrations in concert with a loss of the capacity of Lp(a) to inhibit plasminogen activation upon treatment with DTT. The observed immunological and functional changes of Lp(a) indicate that apo(a) kringle function is severely affected by sulfhydryl compounds.

Dithiothreitol↗
PubMed2000

[Protective effect of nitric oxide on pancreas and its relation to sulfhydryl compounds and oxygen free radicals].

OBJECTIVE: To investigate the effect of endogenous nitric oxide (NO) on acute necrosis pancreatitis in rats and its relation to sulfhydryl compounds and lipid peroxidation. METHODS: Acute necrosis pancreatitis in rats was induced by retrograde sodium taurocholate (5%) infusion into the pancreatobiliary duct (1 ml/kg body weight), and N(G)-nitro-L-arginine (L-NNA) was used as the inhibitor of endogenous NO. The effect of endogenous NO on pancreatic injury, serum amylase level, the pancreatic tissue levels of sulfhydryl compounds, and malonaldehyde (MDA, the end product of lipid peroxidation) was evaluated, respectively. RESULTS: Sodium taurocholate administration induced evident pancreatic tissue edema and acinar necrosis, and intrapancreatic hemorrhage occurred in 2/7 rats. Both serum amylase and tissue MDA [(1.25 +/- 0.28) nmol/mg x pr vs. (0.5 +/- 0.03) nmol/mg x pr, P < 0.05] were significantly increased, but tissue sulfhydryl compounds were decreased markedly. Pretreatment with the NO inhibitor, L-NNA (12.5 mg/kg body weight), significantly intensified acinar necrosis and increased the intrapancreatic hemorrhage (10/12). L-NNA also resulted in a further increase of serum amylase and tissue MDA [(3.0 +/- 0.40) vs. (1.25 +/- 0.28) nmol/mg x pr, P < 0.05], but it had no effect on the tissue sulfhydryl compounds. CONCLUSION: Endogenous NO has the effect of pancreatic protection, and its antioxidation may be responsible, at least in part, for the protective mechanisms. Sulfhydryl compounds may not be involved in NO's pancreatic protection mechanisms.

Amylases↗
PubMed1991

Factors influencing the in vitro growth of Mycobacterium leprae: effect of sulfhydryl compounds.

In an attempt to determine the factors that influence the in vitro growth of Mycobacterium leprae in DH medium, the effects of sulfhydryl compounds were studied. Growth of M. leprae was monitored using two biochemical indicators. Only the sulfhydryl compounds, in reduced form, containing carboxyl group could support the growth of M. leprae. Higher cell yields were obtained when these sulfhydryl compounds were supplemented with dithiothreitol, presumable to keep the monothiols in reduced state during long incubation periods. Ascorbic acid could not replace dithiothreitol for this purpose. It is suggested that these carboxylated sulfhydryl compounds play a role in the metabolic activity of M. leprae along with maintaining low redox potential of the medium.

Adenosine Triphosphate↗
PubMed1991

Regional variations in total and nonprotein sulfhydryl compounds in the human gastric mucosa and effects of ethanol.

This study evaluated the regional distribution of sulfhydryl compounds in the human gastric mucosa and the effect of ethanol on gastric sulfhydryl tissue levels. Total sulfhydryl, glutathione, and cysteine and their oxidized forms were measured in biopsy specimens taken from the gastric body and antrum of 22 healthy volunteers. Total sulfhydryl and glutathione contents of the body of the stomach were significantly higher than those of the antrum. In contrast, cysteine concentration was higher in the gastric antrum than in the body. No difference was found in the levels of oxidized sulfhydryls between the gastric body and antrum. The effect of acute administration of ethanol on gastric sulfhydryl content was studied in nine subjects. Ethanol caused gross mucosal damage and lowered the concentration of sulfhydryl compounds in both the body and the antrum. In 10 chronic alcoholics total sulfhydryl and glutathione, but not cysteine, were markedly decreased in the gastric body but not in the antrum as compared with nonalcoholic controls. In conclusion, 1) the human gastric body contains significantly higher tissue levels of total sulfhydryls and glutathione and lower concentrations of cysteine than the antrum; 2) ethanol in a damaging concentration significantly decreases gastric tissue levels of sulfhydryl compounds; and 3) chronic ethanol intake lowers total sulfhydryl and glutathione tissue levels in the gastric body.

Adult↗
PubMed1994

Protective effects of sulfhydryl compounds on HOCl-induced intracellular Ca2+ increase in single rat ventricular myocytes.

Effects of sulfhydryl compounds on cell injuries caused by hypochlorous acid (HOCl) were studied in isolated rat cardiomyocytes by way of continuous measurement of intracellular Ca2+ using calcium sensitive fluorescent dye, fura-2. Ten minutes exposure of the cell to 100 microM HOCl induced a significant increase in the intracellular free calcium concentration ([Ca2+]i) from 90 +/- 20 nM to 266 +/- 74 nM (n = 44, mean +/- S.D.). This increase in [Ca2+]i was reversed by subsequent application of dithiothreitol (DTT) in a dose dependent manner; 30 microM DTT was found effective, while 2 mM DTT almost completely restored the [Ca2+]i to the control level. Similar to DTT, cysteine ethyl ester and cysteine methyl ester could also reverse the HOCl-induced rise of [Ca2+]i where the order of the potency was DTT > cysteine ethyl ester > cysteine methyl ester. In contrast, increase in [Ca2+]i induced by HOCl was not recovered by application of other sulfhydryl compounds such as cysteine and glutathione. Since HOCl administrated in the presence of cysteine failed to induce an increase in [Ca2+]i, we conclude that membrane permeable sulfhydryl compounds may reverse the increase in [Ca2+]i caused by HOCl.

Animals↗
PubMed1989

Involvement of cellular sulfhydryl compounds in the inhibition of RNA synthesis by selenite.

Selenite has been shown previously to inhibit cellular RNA synthesis. Based upon our previous observation that selenite inhibits purified RNA polymerase only in the presence of a sulfhydryl compound (Frenkel et al., Mol Pharmacol 31: 112-116, 1987), we hypothesized that the inhibition of cellular RNA synthesis by selenite involves endogenous sulfhydryl compounds. We found that depletion of cells of endogenous sulfhydryl compounds, by exposure to diethylmaleate (DEM), virtually eliminated the inhibitory effect of a 1-hr exposure of cells to selenite. This inhibition was restored to normal or higher levels when the selenite was reacted with glutathione or cysteamine prior to addition to the DEM-treated cells. RNA synthesis in DEM-treated cells was inhibited after a 4-hr exposure to higher concentrations of selenite. In contrast to the effect of DEM, specific depletion of the cells of glutathione, by exposure to buthionine sulfoximine, had no effect on the inhibition of RNA synthesis by selenite. These results demonstrate the involvement of endogenous cellular sulfhydryl compounds in the inhibition of RNA synthesis by selenite, but indicate that glutathione, in particular, is not involved in this inhibition.

HeLa Cells↗