Optimizing separation efficiency of 2-DE procedures for visualization of different superoxide dismutase forms in a cellular model of amyotrophic lateral sclerosis

Neurodegenerative diseases such as Alzheimer disease (AD) and Parkinson disease (PD) have been associated with increased production of reactive oxygen species. In AD and PD patients, superoxide dismutase (SOD1) was also indicated as a major target of oxidative damage. In particular, in brain tissue of these patients, different SOD1 isoforms have been identified, although their functional role still remains to be elucidated. In the light of the possibility that different SOD1 entities could be expressed also in other neurodegenerative disorders, as a sort of unifying event with AD and PD, we have investigated amyotrophic lateral sclerosis (ALS) using human neuroblastoma SH-SY5Y cells with mutated SOD1 gene H46R as cellular model. 2-DE using a narrow-range IPG 4-7 strips in the first dimension and linear 15% SDS-PAGE in the second allowed to separate different SOD1 spots. MALDI-TOF MS and CapLC-MS/MS have been used for their complete identification. This is the first report in which the presence of SOD1 (iso) forms in a cellular model of ALS has been evidenced.     

A new crown ether as vesicular carrier for 5-fluoruracil: synthesis, characterization and drug delivery evaluation

Niosomes have shown promise as cheap and chemically stable drug delivery systems. In this paper a novel crown ether amphiphile, 1,16-hexadecanoyl-bis-(2-aminomethyl)-18-crown-6 (Bola A-16), has been synthesized with the aim of developing a long time stable controlled release system. Niosomes have been prepared with different molar ratios of amphiphile and cholesterol and their morphological properties have been determined by quasi-elastic light scattering and transmission electron microscopy. The composition of niosomes affects the entrapment efficiency and the release rate of 5-fluorouracil, a well-known antineoplastic molecule. In addition, other two known azacrown ether amphiphiles (4,7,10,13-pentaoxa-16-aza-cyclooctadecane)-hexadecanedioc acid diamide (Bola D-16) and ,ω-(4,7,10,13-pentaoxa-16-aza-cyclooctadecane)-hexadecane (Bola C-16), have been synthesized and the obtained vesicles have been characterized for comparison. Furthermore, the release profile of 5-fluorouracil in vitro, from these niosomes, has been studied over a period of 6 h in order to simulate a hematic adsorption.     

Synthesis of some novel 2,6‐disubstituted pyridazin‐3‐ones as TMC120 analogues

Different analogues of TMC120 derived from pyridazin‐3(2H)‐one rings were synthesized by coupling of 3,6‐dichloropyridazine with arylacetonitriles, phenols and/or aniline derivative followed by hydrolysis and alkylation with different benzyl bromide derivatives.     

Aza-Morita-Baylis-Hillman reactions and cyclizations of conjugated dienes activated by sulfone, ester, and keto groups

The aza-Morita-Baylis-Hillman reactions of aldimines 2 with several activated conjugated dienes were found to proceed smoothly in DMF in the presence of 3-hydroxyquinuclidine (HQD). Imines 2 reacted with 1-(p-toluenesulfonyl)-1,3-butadiene (3), methyl 2,4-pentadienoate (6), hexa-3,5-dien-2-one (7), and 1-phenylpenta-2,4-dien-1-one (8) to afford adducts 4, 13, 14, and 15, respectively. While products 4, 13, and 15 were formed as E,Z mixtures, adducts 14 were obtained as essentially pure E-isomers. Cyclization of the E-isomers of the products derived from the dienyl sulfone 3 and the dienoate ester 6 occurred via intramolecular conjugate addition under base-catalyzed conditions to afford functionalized piperidines 5 and 16, respectively. The aza-Morita-Baylis-Hillman reaction and subsequent cyclization of the imine 2a with 3 were also carried out as a one-pot reaction, while the reaction mixture was simultaneously irradiated at 300 nm to effect the photoisomerization of the unreactive Z-adduct of the corresponding 4 to the more reactive E-isomer.     

Weak limit and blowup of approximate solutions to H-systems

Let be a continuous function such that H(p)→H₀∈R as |p|→+∞. Fixing a domain Ω in R² we study the behaviour of a sequence (un) of approximate solutions to the H-system Δu=2H(u)ux∧uy in Ω. Assuming that supp∈R³|(H(p)−H₀)p|<1, we show that the weak limit of the sequence (un) solves the H-system and un→u strongly in H¹ apart from a countable set S made by isolated points. Moreover, if in addition H(p)=H₀+o(1/|p|) as |p|→+∞, then in correspondence of each point of S we prove that the sequence (un) blows either an H-bubble or an H₀-sphere.     

The origin of transverse anisotropy in axially symmetric single molecule magnets

Single-crystal high-frequency electron paramagnetic resonance spectroscopy has been employed on a truly axial single molecule magnet of formula [Mn(12)O(12)(tBu-CH(2)CO(2))16(CH(3)OH)4].CH(3)OH to investigate the origin of the transverse magnetic anisotropy, a crucial parameter that rules the quantum tunneling of the magnetization. The crystal structure, including the absolute structure of the crystal used for EPR experiments, has been fully determined and found to belong to I4 tetragonal space group. The angular dependence of the resonance fields in the crystallographic ab plane shows the presence of high-order tetragonal anisotropy and strong dependence on the MS sublevels with the second-highest-field transition being angular independent. This was rationalized including competing fourth- and sixth-order transverse parameters in a giant spin Hamiltonian which describes the magnetic anisotropy in the ground S = 10 spin state of the cluster. To establish the origin of these anisotropy terms, the experimental results have been further analyzed using a simplified multispin Hamiltonian which takes into account the exchange interactions and the single ion magnetic anisotropy of the Mn(III) centers. It has been possible to establish magnetostructural correlations with spin Hamiltonian parameters up to the sixth order. Transverse anisotropy in axial single molecule magnets was found to originate from the multispin nature of the system and from the breakdown of the strong exchange approximation. The tilting of the single-ion easy axes of magnetization with respect to the 4-fold molecular axis of the cluster plays the major role in determining the transverse anisotropy. Counterintuitively, the projections of the single ion easy axes on the ab plane correspond to hard axes of magnetization.     

Efficient and selective cleavage of RNA oligonucleotides by calix[4]arene-based synthetic metallonucleases

Di- and trinuclear copper(II) complexes of [12]aneN3 macrocycles anchored at the upper rim of cone calix[4]arenes in 1,2-, 1,3-, and 1,2,3-positions were investigated as cleaving agents of 6-, 7-, and 17-meric oligoribonucleotides. A kinetic investigation of the cleavage reactions was carried out using gel electrophoresis to separate and analyze reactants and products having a radioactive phosphate label in the terminal 5'-position. The degree of cooperation was assessed on the basis of a comparison with rates of cleavage by mononuclear controls. A remarkable selectivity of cleavage of the CpA phosphodiester bond was observed for all metal complexes, in sharp contrast with the UpU and UpG selectivity previously observed in the cleavage of diribonucleoside monophosphates by the same metal complexes. The highest rate acceleration, brought about in the cleavage of the 5'-pCpA bond in hexanucleotide 9 by 50 muM trinuclear complex 5-Cu3 (water solution, pH 7.4, 50 degrees C), amounts to 5 x 105-fold, as based on the estimated background reactivity of the CpA dimer. Selectivity in the cleavage of oligoribonucleotides by copper(II) complexes closely resembles that experienced by ribonuclease A and by a number of metal-independent RNase A mimicks. The possible role of the dianionic phosphate at the 5'-terminal positions as a primary anchoring site for the metal catalyst is discussed.     

Fluorinated organic materials for electronic and optoelectronic applications: the role of the fluorine atom

In this article we highlight, by means of selected examples drawn from work performed in our or other laboratories, the features of some classes of fluorinated conjugated materials and their use in electronic devices such as electroluminescent diodes or field effect transistors. A variety of fluorinated conjugated systems, either molecular or polymeric, such as poly(phenylenevinylene)s, poly(phenyleneethynylene)s, polythiophenes, polyphenylenes, are dealt with. Attention is also focused on a different class of electroluminescent compounds, represented by the cyclometalated iridium complexes with various forms (mer and fac). In particular, fluorine atoms lower both the HOMO and LUMO energy levels. Consequently, the electron injection is made easier, the materials display a greater resistance against the degradative oxidation processes and organic n-type or ambipolar semiconducting materials may result. Moreover, the C-H...F interactions play an important role in the solid state supramolecular organization, originating a typical pi-stack arrangement which enhances the charge carrier mobility.