Academic literature on the topic 'Dimercapto'

The thiol compound 2,5-dimercapto-1,3,4-thiadiazole is a potential cathode material. The redox reactions of the mentioned thiol compound are slow at room temperature but can be enhanced using electron transfer mediators. The electrochemical oxidation of 2,5-dimercapto-1,3,4-thiadiazole on the surface of carbon electrodes modified with Ruthenium(III) Schiff base complex was studied by voltammetric methods and amperometric flow injection analysis. The electrocatalytic properties of Ruthenium(III) Schiff base complex on glassy carbon and screen printed carbon electrodes are enhanced by the addition of multi-walled carbon nanotubes and Nafion. Voltammetric studies showed that anodic oxidation of DMcT on a modified glassy carbon electrode occurs at a potential of +0.28 V vs. Ag/AgCl in Britton-Robinson buffer (pH 6.50). Flow injection amperometric measurements were performed at +0.20 V vs. Ag/AgCl in Britton-Robinson buffer solutions pH 6.50 at a 0.40 cm3 min–1 flow rate. The results of amperometric measurements for modified screen printed and glassy carbon electrodes showed that the screen printed electrode had a lower value of detection limit (0.38 mg dm–3) and quantification (1.28 mg dm–3), and a linear dynamic range from 1 to 500 mg dm–3 of 2,5-dimercapto-1,3,4-thiadiazole. Modified glassy carbon electrode provided a linear dynamic range up to 750 mg dm–3 of 2,5-dimercapto-1,3,4-thiadiazole with a detection limit of 3.90 mg dm–3 and quantification of 13.20 mg dm–3.

1 The standard drug for the treatment of arsenic poisoning is BAL (dimercaprol). BAL possesses marked side-effects and a low safety ratio, drawbacks which new BAL analogues, DMPS and DMSA, do not possess. 2 The efficacy of three chelating agents, BAL, DMPS and DMSA, has been evaluated as a treatment for systemic organic arsenic poisoning, induced by intravenous dichloro(2-chlorovinyl)arsine (lewisite) administration to rabbits. Equimolar dosing schedules were used based upon realistic doses for the most toxic agent, BAL. 3 It was concluded that all three dimercapto chelating agents provided signficant protection against the lethal systemic effects of lewisite, and, under the test conditions reported here, there was no significant difference between them in therapeutic efficacy. 4 The cause of mortality following intravenous lewisite in treated and untreated rabbits was pulmonary damage. 5 It is considered that DMPS and DMSA are worthy of further study as replacements for BAL in the treatment of systemic poisoning by lewisite.

Simple, selective and highly sensitive extraction-photometric methods for determination of Cu, Hg, У Mn, Fe, Co, and Ni are developed using dimercaptophenols (DF) and hydrophobic amines (Am) (2,6-dimercaptophenol(DMP), 2,6-dimercapto-4-methylphenol(DMMP), 2,6-dimercapto-4-ethylphenol(DMEP), 2,6-dimercapto-4-propylphenol(DMPP), and 2,6-dimercapto-4-tertbutylphenol(DMBP)) as complexing reagents. Optimal conditions for formation and extraction of heteroligand compounds (HLC) are specified and the ratios of the components in the complexes are determined. The optimum pH value providing maximum and constant optical density ranges within 3.0-8.1, chloroform (extraction ratio: 98.4-99.6%) being used as an extractant. Optimal concentrations of DP and Am are (0.6 - 0.8) x 10-3and (0.8 - 1.2) x 10-3mol/liter, respectively. HLC are stable and do not decompose for three days in aqueous and organic solvents, and after extraction for more than a month. The maximum analytical signal for M(II) complexing with DP and Am is observed at 464 - 630 nm (εk= 1.82 - 4.40 x 104). The structure of the HLC was studied using thermogravimetry and IR-spectroscopy Comparison of the analytical capabilities of the studied reagents showed that the contrast and sensitivity of the reaction decreases in the series DMBP — DMPP — DMEP — DMMP — DME The interfering impact of ions can be eliminated through changing pH of the medium, masking substances and extraction. The limits of photometric detection and quantitative determination of M (II) in the form of HLC were calculated using calibration graphs. The developed procedures have been successfully used in determination of the trace amounts of Cu, Hg, У Mn, Fe, Co, Ni in different soils: sod-podzolic sandy and sandy-loamy sod-podzolic loamy and clayey, gray forest, black soils, chestnut and river (soil of river floodplains) soils. The determination limits range within 27 - 43 ng/cm3.

This study was undertaken to study the renal toxicity of mercuric chloride in rats at different periods of time. The following groups of rats were studied: i) control, ii) placebo, iii) rats injected with a single ip dose of 100 mg/kg body weight of 2, 3 dimercapto-1-propanesulfonic acid, iv) rats injected with a single ip dose of 100 mg/kg body weight of 2, 3 dimercapto-1-propanesulfonic acid (DMPS) followed by a single dose ip of 2.0 mg HgCl2/kg body weight one hour after DMPS injection v) rats injected with a single ip dose of 2.0 mg HgCl2/kg body weight. Results indicate that mercuric chloride was more toxic after 48 hours of its administration when compared to 24 hours. Mercuric chloride administration caused an impairment of renal function which was evident from a significant decrease in urine volume, urinary excretion of urea, creatinine and glomerular filteration rate (P < 0.001) when compared to other treated groups. There was an increased excretion of protein, albumin and γ–-glutamyltransferase in the urine of mercuric chloride treated rats. Administration of 2, 3 dimercapto-1-propanesulfonic acid before mercuric chloride treatment caused the altered indices to return to near normal levels.

Adsorbent magnetite-dimercapto-silica (Fe3O4 - DMS) is a synthesis of magnetite with 2,3-dimercapto-1-propanol which has been applied to adsorb anions [AuCl4] - and [Cr2O7]-2. The adsorption process of metal anion [AuCl4]- at pH 5 with a contact time of 100 minutes was found optimum results at an adsorption capacity of 77.58 mg/g and an adsorption efficiency value of 96.975%. While the optimum conditions of metal anion [Cr2O7]-2 after the adsorption process at pH 4 with a contact time of 90 minutes was found an adsorption capacity of 85.0426 mg/g and an adsorption efficiency value of 85.0426%. The adsorption efficiency of metal anions [AuCl4]- is higher than the adsorption efficiency of metal anions [Cr2O7] -2

The influence of zinc and copper supplementation during chelation therapy to reduce zinc and copper imbalance and promote lead elimination from the body, was investigated in rats poisoned with lead. The simultaneous supplementation of zinc and copper increased urinary lead excretion by calcium disodium ethylenediamine tetraacetic acid (CaNa2EDTA) compared to treatment with CaNa2EDTA alone. Combination therapy was effective in potentiating the depletion of blood and renal lead by CaNa2EDTA and meso 2,3-dimercapto succinic acid (DMSA). Combination therapy was also more effective in reducing hepatic lead by CaNa2EDTA and blood lead by 2,3-dimercapto propane sulphonate (DMPS). Zinc and copper supplementation produced a more effective reversal of inhibited blood δ-aminolevulinic acid dehydratase (ALAD) activity, urinary δ-aminolevulinic acid excretion and depleted body zinc and copper status.

El objetivo de esta Tesis es la síntesis, caracterización y estudio de polímeros mono- y bidimensionales de alta conductividad eléctrica derivados de bis(ditiolato)metalatos o tetratiolatos. Para ello se han escogido ligandos sulfurados con alto número de átomos de S que permitan interaccciones fuertes entre ellos. Por otra parte, para una mejor comprensión de la relación conductividad- estructura también se ha procedido al estudio de diversos compuestos mono o dinucleares discretos, obtenidos con tales ligandos. Finalmente, se ha iniciado el estudio de compuestos mixtos planares con un ditiolato y un ligando aminado plano, habiéndose escogido para tal estudio el ligando nitrogenado 2,2'-bipiridilo. En todos los casos se ha procedido al estudio con los cationes Ni(II), Pd(II),Pt(II) , Au(III) y Cu(II) de gran tendencia a la coordinación planocuadrada.

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In this study, acute effects of mercury on mouse blood, kidneys and liver were evaluated. Mice received a single dose of mercuric chloride (HgCl2 - 4.6 mg/kg, subcutaneously) for three consecutive days. We investigated the possible beneficial effects of antioxidant therapy (N-acetylcysteine (NAC) and diphenyl diselenide (PhSe)2) comparing to sodium salt of 2,3-dimercapto-1-propanesulfonic acid (DMPS), an effective chelating agent on mercury exposure in mice. We also verified if metallothionein (MT) induction would be involved in a possible mechanism of protection against mercury poisoning and if different therapies would modify MT levels and other toxicological parameters. The results demonstrated that animals treated with mercuric chloride presented a reduction in the body weight gain and therapies did not were effective in reverting this damage. HgCl2 exposure inhibited δ-aminolevulinic dehydratase (δ-ALA-D) activity in liver and only DMPS treatment prevented the inhibitory effect. Animals treated with mercury presented an increase in renal NPSH and therapies did not modify these levels. Urea concentration was increased after mercury exposure. NAC plus (PhSe)2 was partially effective in protecting against this effect of mercury . DMPS and (PhSe)2 were effective in restoring the increment in urea concentration caused by mercury. Thiobarbituric acid-reactive substances (TBARS), ascorbic acid levels, aspartate (AST) and alanine (ALT) aminotransferases were not modified after mercury exposure. Moreover, mercury poisoning caused an increase in hepatic and renal MT levels and antioxidant therapies did not modify this parameter. Our data pointed out the lack of the therapeutic effect of antioxidants tested.
Neste trabalho foram avaliados os efeitos da intoxicação aguda induzida por cloreto de mercúrio (HgCl2) em sangue, rim e fígado de camundongos. Os animais receberam uma única dose de HgCl2 (4,6 mg/Kg de peso), via sub-cutânea, por três dias consecutivos. Investigou-se o possível efeito protetor da terapia com antioxidantes (N-acetilcisteína-NAC e disseleneto de difenila-(PhSe)2) comparando ao ácido 2,3-dimercapto-1-propanosulfônico (DMPS), um agente quelante efetivo contra intoxicações por mercúrio. Além disto, foi verificado se a indução de metalotioneínas (MT) poderia estar envolvida em um possível mecanismo de proteção contra a intoxicação pelo mercúrio e se as diferentes terapias poderiam modificar os níveis de MT e outros parâmetros toxicológicos. Os resultados demonstraram que os animais tratados com cloreto de mercúrio apresentaram uma redução no ganho de peso corporal e as terapias não foram efetivas em reverter este dano. A exposição ao HgCl2 causou inibição na atividade da enzima δ-aminolevulinato desidratase (δ-ALA-D) em fígado de camundongos e somente a terapia com DMPS foi efetiva em reverter esta inibição. Os animais tratados com mercúrio apresentaram um aumento nos níveis de NPSH renal e as terapias não modificaram estes níveis. A concentração de uréia foi aumentada nos animais expostos ao cloreto de mercúrio. A terapia com NAC + (PhSe)2 foi parcialmente efetiva em proteger contra este efeito do mercúrio. Já as terapias com DMPS e (PhSe)2 foram efetivas em proteger contra o aumento nos níveis de uréia induzido pelo mercúrio. As substâncias reativas ao ácido tiobarbitúrico (TBARS), os níveis de ácido ascórbico e as transaminases (aspartato-AST e alanina-ALT) não foram alteradas após a exposição ao HgCl2. Além disso, os resultados demonstraram que a exposição ao mercúrio causou um aumento nos níveis de metalotioneínas hepático e renal e as terapias com antioxidantes não modificaram este parâmetro. Nossos dados apontam para a falta de efeito terapêutico dos antioxidantes testados.

Etude de l'emploi d'un coordinat assembleur qui puisse par coordination avec le centre metallique utilise (metaux de transition du groupe viii) aboutir a un agencement a une dimension des motifs moleculaires par empilement d'entites monomeres ou par formation de chaines. Par utilisation du coordinat squarate sous ses formes oxygenees et soufrees, obtention d'un certain nombre de complexes de pt, pd, ni et cu repondant aux criteres fixes. Etude des structures de ces composes, de leurs proprietes physiques et de la relation structure-propriete. La nature du coordinat comme le caractere specifique de l'arrangement structural ont ete discutes pour une approche de la comprehension de la nature de ces proprietes physiques

Etude des proprietes electriques et structurales de deux series de composes a coordinat dmit : composes a etat d'oxydation fractionnaire (m(dmit)::(2))c::(x) et composes donneur-accepteur d(m(dmit)::(2))::(y) (avec m = zn,ni,pt,pd; c = nbu**(+)::(4) et asph**(+)::(4); d = ttf, tmttf, ttmttf, bedt-ttf et tmtsf; n dans (m(dmit)::(2))**(n-) etant egal a 2,1,x,0). Mise en evidence de la nature 2d des composes de la premiere serie et quasi 3d de ceux de la deuxieme; relations structure-conductivite. Mise en evicence de la supraconduction dans le cas du complexe ttf(ni(dmit)::(2))::(2), avec une temperature de transition de 1,62 k sous 7 kbar

Die Niere stellt das wichtigste Zielorgan für die Akkumulation von anorganischem Quecksilber dar. Versuche an Ratten ergaben, dass bereits wenige Stunden nach Injektion einer geringen Menge Quecksilberchlorid 50% dieser Dosis in den Nieren akkumuliert war. Durch verschiedene Untersuchungen wurden die proximale Tubuli (Pars convoluta et recta) als Ort der Quecksilber-Anreicherung identifiziert. Der Schwermetallchelator DMPS (2,3-Dimercapto-1-Propansulfonsäure) ist heutzutage das Mittel der Wahl für die Behandlung von Vergiftungen mit anorganischem Quecksilber. DMPS hat sich gegenüber dem früher verwendeten BAL aus mehreren Gründen als überlegen erwiesen: in klinischen Tests bezüglich der Quecksilberentgiftung zeigt DMPS die größere Wirksamkeit, kann oral angewendet werden und ist zudem weitaus weniger toxisch als sein Vorgänger BAL. Jedoch war der Wirkmechanismus von DMPS nicht genau bekannt. Allerdings existieren zahlreiche in-vivo- und in-vitro-Studien, die zeigen, dass das organische Anion DMPS ein Substrat des „klassischen Organische-Anionen-Transportsystems“ bzw. des 1997 klonierten, tertiär aktiven Anionenaustauschers OAT1 sein könnte. In dieser Arbeit sollte untersucht werden, ob eine direkte Interaktion zwischen DMPS und OAT1 stattfindet und DMPS ein Substrat von OAT1 ist. Von entscheidendem Interesse war dabei die Frage, ob der Redoxzustand von DMPS (reduziert-monomer, oxidiert-dimer) einen Einfluß auf einen möglichen Transport durch OAT1 hat. Darüber hinaus sollte die Rolle von Albumin, welches unter physiologischen Bedingungen im Blutkreislauf des Menschen in hoher Konzentration vorhanden ist, bei diesem Vorgang geklärt werden. In einem zweiten Teil lag das Interesse auf den Mechanismen, die DMPS und v.a. den intrazellulär gebildeten Quecksilber-DMPS-Komplex (Hg-DMPS-Chelat) aus der Tubuluszelle sezernieren und damit aus dem Organismus eliminieren. Dabei sollte insbesondere die Rolle des apikal lokalisierten, passiven Transporters OAT-K2 („kidney-specific“ Organische-Anionen-Transporter 2) geklärt werden. Die Untersuchung der Transportvorgänge an hOAT1 (menschliches Ortholog von OAT1) und OAT-K2 wurden an Xenopus laevis Ooztyen, HeLa-Zellen sowie OK-Zellen durchgeführt Das organische Anion DMPS war sowohl in reduzierter als auch in oxidierter Form in der Lage, den Transport von PAH kompetitiv zu hemmen: Ki (reduziertes DMPS) = 22.4 mM bzw. Ki (oxidiertes DMPS) = 66.0 mM DMPS-Äquivalente. Bei Anwesenheit von 0.1mM Albumin erlosch die Hemmung des PAH-Transports durch reduziertes und oxidiertes DMPS vollständig. Albumin alleine hatte hingegen keinen Einfluß auf den PAH-Transport durch hOAT1. Die Transstimulations-Experimente an hOAT1-transfizierten HeLa-Zellen zeigten, dass reduziertes und oxidiertes DMPS den Efflux von PAH stimulieren konnten: innerhalb von drei Minuten wurden so 10 bzw. 8% des PAH-Zellgehaltes aktiv über hOAT1 aus der Zelle sezerniert. Das Hg-DMPS-Chelat hatte im Gegensatz zu den beiden Einzelkomponenten Quecksilber und DMPS keinen hemmenden Einfluß auf den PAH-Transport in Oozyten. Damit hat der Komplex auch keine Affinität zu hOAT1, womit der basolaterale Weg für die Elimination des gebundenen Quecksilbers aus der Zelle keine Rolle spielt. Untersuchungen an OAT-K2 konnten aufgrund eines zu niedrigen Expressionsniveaus des Transporters in Oozyten und MDCK-Zellen nicht durchgeführt werden. OK-Zellen, die OAT1 aufgrund ihres Ursprungs aus dem proximalen Tubulus des Opossums endogen exprimieren, waren in der Lage, reduziertes DMPS transzellulär zu sezernieren. Ein Teil dieses Transports konnte durch PAH inhibiert werden. Damit zeigte sich nicht nur, dass hOAT1 DMPS als Substrat für den Transport über die basolaterale Membran akzeptiert, sondern darüber hinaus auch, dass in der apikalen Membran der Tubuluszelle Transporter lokalisiert sind, die DMPS in das Tubuluslumen sezernieren können. Die vorliegenden Ergebnisse dieser Arbeit zeigen, dass hOAT1 eine tragende Rolle im Wirkmechanismus des Quecksilberantidots DMPS spielt: hOAT1 ist entscheidend am Transport von DMPS an den Ort der Vergiftung, die proximale Tubuluszelle, beteiligt. Dabei spielt es keine Rolle, ob die reduzierte oder oxidierte Form am Transporter vorliegt, da beide nachweislich Substrate von hOAT1 sind. Von wesentlicher Bedeutung ist die lockere Bindung von DMPS an Albumin, die DMPS einerseits vor einer raschen glomerulären Filtration bewahrt, andererseits aber durch einfaches Abdiffundieren eine rasche Gleichgewichtseinstellung mit dem perivaskulären Intersitium der Niere und anschließenden Transport in die Tubuluszelle erlaubt. Das intrazellulär gebildete Hg-DMPS-Chelat hat im Gegensatz zu DMPS keine Affinität zu hOAT1, wodurch eine Rückkehr des mobilisierten Quecksilbers in den Körperkreislauf auf diesem Weg verhindert wird
The kidney is the primary target organ in which inorganic mercury (Hg2+) accumulates and expresses its toxic effects. It has been shown that the chelating agent DMPS can rapidly reduce the renal burden of mercury and increase the urinary excretion of mercury. However, the cellular and molecular basis of its efficacy is still unknown. A number of previous studies implicated that the "classical organic anion secretory pathway" is involved in the secretion of DMPS and its chelating products. In this study we used the human isoform of the Organic Anion Transporter (hOAT1) expressed in the Xenopus oocytes expression system to study the interaction of DMPS and its mercury chelates with hOAT1. [3H]PAH was used to show the transport activity of hOAT1 (Km=3.9 mM ±1.3). Uptake of [3H]PAH was inhibited by DMPS (Ki=22.4 mM ± 8.4). We also investigated the interaction of oxidized DMPS with hOAT1 since it has been shown that at least 80% of DMPS in the blood is oxidized within 30min. Oxidized DMPS also inhibited uptake of [3H]PAH (Ki=66 ±13.6mM). In contrast, we found no interaction of the DMPS-Hg-Chelate with hOAT1. To determine whether reduced and oxidized DMPS are transported by hOAT1 we examined the effect of inwardly directed anion gradients on [3H]PAH-loaded HeLa-cells transiently transfected with hOAT1: PAH, DMPS and oxidized DMPS significantly transstimulated efflux of [3H]PAH. These data suggest that hOAT1 can transport reduced and oxidized DMPS, whereas the DMPS-Hg-Chelate does not seem to have any affinity for the transporter. Therefore hOAT1 seems to play a fundamental role in the antidotal action of DMPS by giving the antidote access to the cells of the proximal tubule, the primary site of mercury accumulation. Moreover, the formation of the DMPS-Hg chelate in the blood plasma prevents more mercury from accumulating in the kidney and, once the DMPS-Hg-Chelate has formed inside the tubule cell, no back leak to the blood via hOAT1 is possible because the DMPS-Hg-Chelate has no affinity to hOAT1. The importance of other mechanisms, particularly transport of DMPS and its chelates across the apical membrane of proximal tubule cells, are at present not known