Penicillamine

High-molecular-weight hyaluronan (HA) samples were exposed to free-radical chain-degradation reactions induced by ascorbate in the presence of Cu(II) ions - the so-called Weissberger's oxidative system. The concentrations of both reactants [ascorbate, Cu(II)] were comparable to those that may occur during an early stage of the acute phase of joint inflammation. The time-dependent changes of the viscosity of the HA solution in the absence of the substance tested were monitored by rotational viscometry. However, when the anti- or pro-oxidative effects of the antioxidants/drugs were investigated, their dose-dependency was also examined. Additionally, the anti-oxidative activities of these substances were screened by the well-established ABTS and DPPH decolorization assays. The actions of the disease-modifying anti-rheumatic drugs, namely bucillamine and D-penicillamine, were compared to those of L-cysteine and of SA981, the oxidized metabolite of bucillamine. The results indicated...

A urinary copper (Cu) >25 micromol/24 h following penicillamine had a reported specificity of 98.2% and sensitivity of 88.2% in diagnosing Wilson's disease (WD). We have re-evaluated this test. Ninety-eight subjects were studied at presentation. Thirty-eight (19 girls, 19 boys; median age 10.3 years; range 5-16 years) had an ultimate diagnosis of WD. Sixty (24 girls, 36 boys; median age 10.1, range 2.3-15 years) had other liver disorders. Urinary Cu was estimated for 24h before (basal Cu) and for 24h whilst giving penicillamine 500 mg orally 12 hourly x 2 (post-penicillamine Cu). Both basal Cu and post-penicillamine Cu differed significantly between WD patients and controls (basal Cu: median 6.5 micromol/24 h, range 0.9-109 micromol/24 h, versus median: 0.8 micromol/24 h, range 0.1-19.5, p<0.0001; post-penicillamine Cu: median 36.9 micromol/24 h, range 1.98-219 micromol/24 h, versus median 12.35 micromol/24 h, range 0.5-49.8 micromol/24 h, p<0.0001). A post-penicillamine Cu >25 micromol/24 h was observed in 29/38 patients with WD and in 4/60 controls. 25/38 WD patients were symptomatic. Twenty-three of these and 6/13 asymptomatic siblings had a positive test. The test had a sensitivity of 76% (95% confidence interval [CI], 59.8-88.6%) and a specificity of 93% (95% CI, 83.8-98.2%). Sensitivity was better in symptomatic patients (92%, [95% CI; 74-99%]) than asymptomatic (46%, [95% CI; 19.2-74.9%]). This test is valuable in the diagnosis of WD with active liver disease, but is unreliable to exclude the diagnosis in asymptomatic siblings.

The present review provides an update of the general principles for the investigation and use of chelating agents in the treatment of intoxications by metals. The clinical use of the old chelators EDTA (ethylenediamine tetraacetate) and BAL (2,3-dimercaptopropanol) is now limited due to the inconvenience of parenteral administration, their own toxicity and tendency to increase the neurotoxicity of several metals. The hydrophilic dithiol chelators DMSA (meso-2,3-dimercaptosuccinic acid) and DMPS (2,3-dimercapto-propanesulphonate) are less toxic and more efficient than BAL in the clinical treatment of heavy metal poisoning, and available as capsules for oral use. In copper overload, DMSA appears to be a potent antidote, although d-penicillamine is still widely used. In the chelation of iron, the thiols are inefficient, since iron has higher affinity for ligands with nitrogen and oxygen, but the new oral iron antidotes deferiprone and desferasirox have entered into the clinical arena. ...

Toxic effects of unconjugated bilirubin (BR) in neonatal hyperbilirubinemia have been related to redox and/or coordinate interactions with Cu. However, the development and mechanisms of such interactions at physiological pH have not been resolved. This study shows that BR reduces Cu to Cu in 1:1 stoichiometry. Apparently, BR undergoes degradation, i.e. BR and Cu do not form stable complexes. The binding of Cu to inorganic phosphates, liposomal phosphate groups, or to chelating drug penicillamine, impedes redox interactions with BR. Cu undergoes spontaneous oxidation by O resulting in hydrogen peroxide accumulation and hydroxyl radical production. In relation to this, copper and BR induced synergistic oxidative/damaging effects on erythrocytes membrane, which were alleviated by penicillamine. The production of reactive oxygen species by BR and copper represents a plausible cause of BR toxic effects and cell damage in hyperbilirubinemia. Further examination of therapeutic potentials o...

Zinc stabilizes membranes and DNA and inhibits respiration in somatic cells. It is present in high concentrations in the male reproductive tract and may stabilize spermatozoa prior to fertilization. Herein, we evaluate N-(6-methoxy-8-quinolyl)-p-toluenesulfonamide (TSQ) for analysis of Zn2+ in phosphatidylcholine (PC) vesicles and living spermatozoa using spectrofluorometry and flow cytometry. TSQ: Zn fluorescence in decanol or PC vesicles was compared to that in aqueous buffer. Evaluation of cation specificity, kinetics of TSQ: Zn binding, quenching of TSQ by dithionite and Zn2+ chelation by D-penicillamine established that TSQ is more fluorescent in decanol or PC vesiles than in aqueous buffer, has a high affinity for lipid bilayers and is specific for Zn2+ compared to Mg2+ and Ca2+. Fluorescence measurement of vesicles with and without pretreatment with Zn2+ indicated that, in the absence of Zn2+, 90% of the residual TSQ fluorescence was destroyed by dithionite but >50% was protected by the presence of Zn2+. When D-penicillamine was added the remaining fluorescence was quenched (T1/2 = 10 s) indicating that TSQ remains in/on the membrane. These results established that TSQ can be used to effectively evaluate Zn2+ in artificial membranes and sperm cells. Additional experiments will be necessary to explain the dynamics of TSQ: Zn: membrane interactions. © 1995 Wiley-Liss, Inc.

Young and mature Artemisia princeps var. orientalis (APO, Compositae) are used as a health food and a medicinal plant, respectively, in Korea. Here, we identified the in vitro potent peroxynitrite (ONOO−)-scavenging effect (IC50, 0.26 μg/mL) of the components from the EtOAc fraction. Octadecylsilane column chromatography on the EtOAc fraction yielded two caffeoylquinic acid compounds, 3,5-di-O-caffeoyl-muco-quinic acid (1) and methyl 4,5-di-O-caffeoylquinate (2) by NMR spectroscopic data, which have not been reported before from APO. The IC50 values of compounds 1 and 2 were 0.18 ± 0.01 μg/mL and 0.12 ± 0.00 μg/mL, respectively, lower than that of the positive control (L-penicillamine). HPLC data indicated that young APO (1: 30.3 mg/g dried weight, 2: 27.7 mg/g) contained considerably higher quantities of the two caffeoylquinic acids than mature APO (1: 1.77 mg/g dried weight, 2: 4.10 mg/g).

collagen can initiate platelet aggregation or whether a higher degree of polymerization is required. Purified rat skin collagen was prepared in four states. Soluble monomeric collagen, containing 2 /hM calcium chloride, was maintained at 4°C until use. A previously unchar-acterized form of collagen, soluble microfibrillar collagen, was prepared from monomeric collagen containing cal-cium chloride by allowing it to polymerize at 230 C. Viscometric and electron microscopic characterization of microfibrillar collagen indicated polymerization to or-dered native filaments. Particulate native macrofibrillar collagen was prepared from monomeric collagen by allowing it to polymerize at 37°C in the absence of cal-cium. Particulate collagen, in which the fibers were ran-domly associated, was prepared by salt precipitation of calcium-free monomeric collagen. Microfibrillar and na-tive macrofibrillar collagen initiated platelet aggrega-tion, with a lag phase of approximately 60 s. Monomeric col...

Efficacy of thiol chelators viz. N-acetyl cysteine and D-penicillamine (NAC and DPA) along with nutritional supplements viz. zinc acetate, sodium selenite and magnesium sulphate (Zn, Se and Mg) in the treatment of mercury intoxication was investigated in rats. This is of particular interest since high bonding affinity between mercuric ion and the thiol group exits. The mutual antagonism of mercury and selenium is one of the strongest examples of the interaction in the trace element field. Adult rats of Sprague-Dawley strain were administered a bolus dose of dimethyl mercury (10 mg/kg) orally. A significant rise in the aspartate aminotransferase, alanine aminotransferase, serum alkaline phosphatase, lactate dehydrogenase, gamma glutamyltranspeptidase, bilirubin and creatinine were observed. Single mercury exposure also resulted in a significant increase in lipid peroxides with a concomitant decrease in reduced glutathione level in liver, kidney and brain. A decrease in the enzymatic ...

The application of(S)-N-(4-nitrophenoxycarbonyl)phenylalanine methoxyethyl ester,(S)-NIFE, as a new chiral derivatizing agent for the resolution of compounds possessing an amino group is described. Its applicability is demonstrated by the resolution of proteinogenic amino acid enantiomers. The diastereomeric derivatives produced were separated by reversedphase high-performance liquid chromatography. The effects of pH, excess reagent and reaction time on the derivatization kinetics, and the effects of pH and the organic modifier on the separation, were investigated.