Dermatitis de contacto por pseudotatuajes en niños. A propósito de dos casos / Allergic contact dermatitis from pseudotattoing in children. Two cases report

Presentamos dos casos de dermatitis alérgica de contacto por tatuajes de henna negra. Dos niños de 11 y 4 años desarrollan prurito y enrojecimiento sobre tatuaje. No habían tenido contacto previo con tintes de pelo ni con otros tatuajes. Un caso presenta despigmentación en la zona del tatuaje. Observamos en ambos pruebas de contacto intensamente positivas para la parafenilendiamina y colorantes dispersos del grupo azo. Es probable que exista reacción cruzada entre la parafenilendiamina y colorantes del grupo azo (AU)

[Synthesis of functionalized cyanines. Fluorescence properties following complexation of cations]. / Synthèse de cyanines fonctionnalisées. Etude de leurs propriétés de fluorescence en fonction de la complexation de cations.

The ionophoric properties of podands containing dioxazaphosphocane moieties linked by inactive spacers were studied. To increase the detection sensibility of these compounds we introduced a cyanine as spacer. Fluorescence analysis demonstrated the interest of cyanines as active spacers since the complexation by cations as Ca2+ and Mg2+ gives an enhancement of the emission intensity.

Evaluation of [125I]7 alpha-O-iodoallyl diprenophine as a new potential SPECT opioid receptor imaging agent.

A new iodinated diprenorphine analog, [125I]7 alpha-O-iodoallyl diprenorphine ([125I]7 alpha-O-IA-DPN), was prepared by iododestannylation and characterized. As an opioid antagonist, this agent showed very high affinity (Ki = 0.4 +/- 0.2 nM) and 63% of specific binding by in vitro and in vivo binding studies. Inhibition curves indicated that this tracer labeled with the same affinities to three opioid receptors (mu = delta = kappa). The findings demonstrate that this proposed compound appears to be potential radioprobe for future study of opioid receptors by in vivo SPECT.

Cyclization-activated prodrugs: N-(substituted 2-hydroxyphenyl and 2-hydroxypropyl)carbamates based on ring-opened derivatives of active benzoxazolones and oxazolidinones as mutual prodrugs of acetaminophen.

N-(Substituted 2-hydroxyphenyl)- and N-(substituted 2-hydroxypropyl)carbamates based on masked active benzoxazolones (model A) and oxazolidinones (model B), respectively, were synthesized and evaluated as potential drug delivery systems. A series of alkyl and aryl N-(5-chloro-2-hydroxyphenyl)carbamates 1 related to model A was prepared. These are open drugs of the skeletal muscle relaxant chlorzoxazone. The corresponding 4-acetamidophenyl ester named chlorzacetamol is a mutual prodrug of chlorzoxazone and acetaminophen. Chlorzacetamol and two other mutual prodrugs of active benzoxazolones and acetaminophen were obtained in a two-step process via condensation of 4-acetamidophenyl 1,2,2,2-tetrachloroethyl carbonate with the appropriate anilines. Based on model B, two mutual prodrugs of acetaminophen and active oxazolidinones (metaxalone and mephenoxalone) were similarly obtained using the appropriate amines. All the carbamate prodrugs prepared were found to release the parent drugs in aqueous (pH 6-11) and plasma (pH 7.4) media. The detailed mechanistic study of prodrugs 1 carried out in aqueous medium at 37 degrees C shows a change in the Brönsted-type relationship log t1/2 vs pKa of the leaving groups ROH: log t1/2 = 0.46pKa-3.55 for aryl and trihalogenoethyl esters and log t1/2 = 1.46pKa-16.03 for alkyl esters. This change is consistent with a cyclization mechanism involving a change in the rate-limiting step from formation of a cyclic tetrahedral intermediate (step k1) to departure of the leaving group ROH (step k2) when the leaving group ability decreases. This mechanism occurs for all the prodrugs related to model A. Regeneration of the parent drugs from mutual prodrugs related to model B takes place by means of a rate-limiting elimination-addition reaction (E1cB mechanism). This affords acetaminophen and the corresponding 2-hydroxypropyl isocyanate intermediates which cyclize at any pH to the corresponding oxazolidinone drugs. As opposed to model A, the rates of hydrolysis of mutual prodrugs of model B clearly exhibit a catalytic role of the plasma. It is concluded from the plasma studies that the carbamate substrates can be enzymatically transformed into potent electrophiles, i.e., isocyanates. In the case of the present study, the prodrugs are 2-hydroxycarbamates for which the propinquity of the hydroxyl residue and the isocyanate group enforces a cyclization reaction. This mechanistic particularity precludes their potential toxicity in terms of potent electrophiles capable of modifying critical macromolecules.

Inhibition of Adenosine Triphosphatase Activity from a Plasma Membrane Fraction of Acer pseudoplatanus Cells by Carbanilate Derivatives.

Thirty-one carbanilate derivatives were assayed for their capabilities to inhibit the ATPase activity of a plasma membrane fraction from Acer pseudoplatanus cells. At a concentration of 100 micromolar, nine compounds strongly inhibited the ATPase activity, with I(50) ranging from 14.5 micromolar to 35 micromolar. These molecules were also inhibitory to plasma membrane ATPases of other origins: plant (maize shoot), yeast (Schizosaccharomyces pombe), and animal (dog kidney). The most efficient molecule appeared to be 2,2,2-trichloroethyl 3,4-dichlorocarbanilate.

Inhibition of Adenosine Triphosphatase Activity from a Plasma Membrane Fraction of Acer pseudoplatanus Cells by 2,2,2-Trichloroethyl 3,4-Dichlorocarbanilate.

2,2,2-Trichloroethyl 3,4-dichlorocarbanilate (SW26) is toxic for Acer pseudoplatanus cell cultures. It inhibited the cellular proton extrusion and depolarized the plasmalemma. In vitro, it inhibited the plasma membrane ATPase. SW 26 was also inhibitory to membrane ATPases of other origins-plant (maize shoot), fungus (Schizosaccharomyces pombe), and animal (dog kidney)-with about the same efficiency (7.5 micromolar < I(50) < 22 micromolar). It did not inhibit the oligomycin-sensitive ATPase from purified plant mitochondria, nor molybdate-sensitive soluble phosphatases. SW26 was more specific for plasma membrane ATPases than diethylstilbestrol or vanadate. A Lineweaver-Burk plot analysis showed that inhibition kinetics were purely noncompetitive (K(i) = 14.7 micromolar) below 20 micromolar. Above this concentration, the inhibition pattern was not consistent with Michaelis-Menten kinetics, and a Hill plot representation revealed a positive cooperativity.