Carbonic anhydrase inhibitors. Sulfonamide diuretics revisited--old leads for new applications?

Sulfonamide diuretics such as hydrochlorothiazide, hydroflumethiazide, quinethazone, metolazone, chlorthalidone, indapamide, furosemide and bumetanide were tested as inhibitors of the zinc enzyme carbonic anhydrases (CAs, EC 4.2.1.1). These drugs were discovered in a period when only isoform CA II was known and considered physiologically/pharmacologically relevant. We prove here that although acting as moderate to weak inhibitors of CA II, all these drugs considerably inhibit other isozymes known nowadays to be involved in critical physiologic processes, among the 16 CAs present in vertebrates. Some low nanomolar/subnanomolar inhibitors against such isoforms were detected, such as among others metolazone against CA VII, XII and XIII, chlorthalidone against CA VB, VII, IX, XII and XIII, indapamide against CA VII, IX, XII and XIII, furosemide against CA I, II and XIV, and bumethanide against CA IX and XII. The X-ray crystal structure of the CA II-indapamide adduct was also resolved at high resolution, and the binding of this sulfonamide to the enzyme was compared to that of dichlorophenamide, sulpiride and a pyridinium containing sulfonamide. Indapamide binds to CA II in a manner not seen earlier for any other CA inhibitor, which might be important for the design of compounds with a different inhibition profile.     

Direct-type vinylogous Mukaiyama-Michael addition reactions involving pyrrolinone donors

The direct Mukaiyama-Michael addition of vinylogous tetramate donors to a number of different Michael acceptors has been easily executed, by employing the TMSOTf/Et₃N mixture as soft Lewis acid/base promoter agent. Richly functionalized, highly manipulable γ-substituted pyrrolinone products were practically synthesized in acceptable to excellent yields, and with diastereoselectivities heavily relying upon the substituent at the nitrogen atom of the pyrrolinone donor.     

Photodynamic therapy in the treatment of actinic keratosis

The efficacy of photodynamic therapy (PDT) with 5-aminolevulinate and methyl aminolevulinate in the treatment of actinic keratosis has been demonstrated in a large number of clinical studies over the last several years. Here, we recapitulate the major findings, comparing the various photosensitizers, light sources and therapeutic regimens, and present a retrospective analysis of 142 own cases treated with 259 PDTs. In addition, we also discuss the value of PDT in comparison with cryotherapy or 5-fluorouracil. The efficacy and the low risk of side effects of PDT have resulted in a high patient preference in clinical trials.     

Polar substituent effect of the ester group on conformational equilibria of O-mono-substituted cyclohexanes—the para-substituent effect in cyclohexyl benzoates

Together with the nonsubstituted reference compound, para-methoxy- and para-nitro cyclohexyl benzoates have been synthesized and their conformational equilibria studied by low temperature NMR spectroscopy and theoretical DFT calculations. The free energy differences ΔG° between axial and equatorial conformers were examined with respect to polar substituent influences on the conformational equilibrium of O-mono-substituted cyclohexane.     

Catalytic behavior of supported Pd catalysts in the selective hydrogenation of campholenic aldehyde to naturanol

Selective catalytic reduction of campholenic aldehyde to naturanol was investigated over Sn-and Fe-doped SiO₂, and Fe₂O₃-supported Pd catalysts. On Pd/SiO₂ and Pd-Sn/SiO₂ only saturated campholenic aldehyde is formed. Addition of Fe increases the C=O hydrogenation rate producing the corresponding unsaturated alcohol with a good selectivity. Also Fe₂O₃-supported catalysts were found to be more selective towards carbonyl hydrogenation. Addition of tin to Pd/Fe₂O₃ contributes to a further selectivity enhancement towards naturanol.     

Suspension bead array branch migration displacement assay for rapid STR analysis

STR analysis is commonly used in forensic and genetic studies. STRs are currently discriminated based on size, primarily by gel- and column-based approaches. Hybridization-based approaches have the potential to allow high-throughput analysis of STRs; however, development of such approaches has been limited by the difficulty in discriminating between STRs of similar length. We have recently described several innovations to enable STR analysis using an array-based hybridization approach for high- throughput STR analysis. Here we extend that approach by incorporating the array into microspheres and adding a discriminatory branch migration displacement step. This microsphere-based platform uses Luminex xMAP technology and improves the sensitivity, selectivity, and speed of the assay. We demonstrate the feasibility, speed, and reliability of the assay for STR detection by correctly analyzing two STR loci in 20 forensic DNA samples of known STR type. The multiplex, bead-based approach provides a high-throughput and more portable STR analysis.     

Statistical data processing of mobility curves of univalent weak bases

This paper brings a new rigorous and complete statistical approach to the data processing of the mobility curves of univalent weak bases. This approach is based on application of the least square method to the equation of the related mobility curve. Thus, an equation for the best fit is derived and its mathematical solution is found. The solution brings best estimates of the mobility curve parameters, i.e., dissociation constant K and ionic mobility of the protonated base U. Further, explicit formulas have been derived for the calculation of related statistical parameters, i.e., SDs of effective mobility s(u), of the dissociation constant s(K), and of ionic mobility of protonated base s(U). The mathematical functions used in the above approach do not impose any limitations on the data used, i.e., the mobility and pH values used may be real numbers (positive, negative, zero).     

High-resolution 2-DE for resolving proteins, protein adducts and complexes in plasma

A 2-DE system has been devised in which proteins are first separated in their native state followed by separation according to mass under denaturing conditions (Nat/SDS-PAGE). Hydrophilic properties of the gel and the presence of dihydroxybisacrylamide in the first dimension allowed a good resolution for high-molecular-weight proteins and maintained interactions. With this method 252 plasma spots have been resolved and 140 have been characterized by MS as isoforms of 60 proteins, a relevant part of which (12) were not detected by traditional 2-D gels or by other nondenaturing 2-D techniques. The list includes complement factors (C4d, C7), coagulation factors (coagulation factor II, fibrin beta), apolipoproteins (apolipoprotein B) and cell debris (vinculin, gelsolin, tropomyosin, dystrobrevin beta, fibrinectin I). Nat/SDS PAGE also allowed separation of nicked forms of albumin, Apo B100 and alpha2-macroglobulin and showed the presence of atypical albumin adducts corresponding to post-translational and oxidation products. Our system provides therefore new tools for resolving proteins, protein aggregates and complexes and amplifies the potentiality of traditional electrophoretic analysis.     

Peptidomic approach based on combined capillary isoelectric focusing and mass spectrometry for the characterization of the plasmin primary products from bovine and water buffalo beta-casein

The main peptides produced by hydrolysis of water buffalo beta-casein with plasmin were characterized by capillary electrophoresis and mass spectrometry and compared with their bovine homologous. A novel breakdown product arising from the hydrolysis of water buffalo beta-casein, originated by the presence of a plasmin-sensitive Lys bond at position 68 was identified, which was not present in bovine beta-casein. On the basis of this evidence, an improved procedure for the detection and the differentiation of the products of plasmin hydrolysis of bovine and water buffalo beta-casein by capillary isoelectric focusing was set-up. In the experimental conditions, the gamma-casein from the two species was efficiently separated. Comparison of the capillary electropherograms with those obtained by ultra-thin-layer isoelectric focusing, the reference method for routine analysis of plasmin digests of casein, suggests that capillary electrophoresis isoelectric focusing may constitute a successful alternative to the traditional slab gel electrophoresis analysis of plasmin digests of casein either for basic structural studies or for applications in the quality assessment of dairy products.