Antimycobacterial and antitumor activities of Palladium(II) complexes containing isonicotinamide (isn): X-ray structure of trans-[Pd(N-3)(2)(isn)(2)]

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Synthesis, characterization, X-ray structure and in vitro anti mycobacterial and antitumoral activities of Ru(II) phosphine/diimine complexes containing the "SpymMe(2)" ligand, SpymMe(2)=4,6-dimethyl-2-mercaptopyrimidine

Conselho Nacional de Desenvolvimento Científico e Tecnológico (CNPq)

A duplicated nitrotienyl derivative with antimycobacterial activity: synthesis, X-ray crystallography, biological and mutagenic activity tests

A duplicated nitrotienyl derivative was obtained as a by-product from the synthesis of a proposed molecular hybrid of a nitrotienyl derivative and isoniazid with an expected dual antimycobacteria mechanism. The structure was shown to be the 5,5'-dinitro-2(2,3-diaza-4-(2'-tienyl)buta-1,3-dienyl)tiophene by X-ray crystallography. The minimal inhibitory concentration (MIC) determination of this compound proved to be promising against Mycobacterium pathogenic strains such as M. avium and M. kansasei, although it had a high level of mutagenicity, as observed in mutagenic activity tests. (c) 2006 Elsevier Masson SAS. All rights reserved.

Synthesis, X-ray structure and antimycobacterial activity of silver complexes with alpha-hydroxycarboxylic acids

In this paper, synthesis, characterization and antimycobacterial properties of a new water-soluble complex identified as silver-mandelate are described. Elemental and thermal analyses are consistent with the formula [Ag(C6H5C(OH)COO)](n). The polymeric structure was determined by single X-ray diffraction and the two-dimensional structure is based on the bis(carboxylate-O,O') dimer [Ag-O, 2.237(3), 2.222(3) angstrom]. The structure is extended along both the b and c axes through two oxygen atoms of a bidentate alpha-hydroxyl-carboxylate residue [Ag-OH(hydroxyl), 2.477(3) angstrom; Ag-O(carboxylate), 2.502(3) angstrom; O-Ag-O, 63.94(9)degrees]. A strong d(10)-d(10) interaction was observed between two silver atoms. The Ag...Ag distance is 2.8307(15) angstrom. The NMR C-13 spectrum in D2O shows that coordination of the ligand to Ag(l) occurs through the carboxylate group in solution. Potentiometric titration shows that only species with a molar metaHigand ratio of 2:2 are formed in aqueous solution. The mandelate complex and the silver-glycolate, silver-malate and silver-hydrogen-tartarate complexes were tested against three types of mycobacteria, Mycobacterium avium, Mycobacterium tuberculosis and Mycobacterium kansasii, and their minimal inhibitory concentration (MIC) values were determined. The results show that the four complexes are potential candidates for antiseptic or disinfectant drugs for discharged secretions of patients affected with tuberculosis. (c) 2006 Published by Elsevier B.V.

Structural Characterization of Nanocrystalline Sb-Doped SnO2 Xerogels by Multiedge X-ray Absorption Spectroscopy

Coordenação de Aperfeiçoamento de Pessoal de Nível Superior (CAPES)

Use of lithium niobate detector for measuring X-ray intensity in mammographic range

A detector system that can measure X-ray intensity in the mammographic range of 22 to 36 kVp (equivalent photon energies ofthe beam between 11 and 15 keV) is presented. It consists of a lithium mobate detector and a high-sensitivity current-to-voltage converter.

Pyroelectric composite film for X-ray intensity detection

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

PZT FOR MEASURING ENERGY FLUENCE RATE of X-RAY USED IN SUPERFICIAL CANCER THERAPY

Fundação de Amparo à Pesquisa do Estado de São Paulo (FAPESP)

Analysis of failed commercially pure titanium dental implants: A scanning electron microscopy and energy-dispersive spectrometer X-ray study

Background: the failure of osseointegration in oral rehabilitation has gained importance in current literature and in clinical practice. The integration of titanium dental implants in alveolar bone has been partly ascribed to the biocompatibility of the implant surface oxide layer. The aim of this investigation was to analyze the surface topography and composition of failed titanium dental implants in order to determine possible causes of failure.Methods: Twenty-one commercially pure titanium (cpTi) implants were retrieved from 16 patients (mean age of 50.33 +/- 11.81 years). Fourteen implants were retrieved before loading (early failures), six after loading (late failures), and one because of mandibular canal damage. The failure criterion was lack of osseointegration characterized as dental implant mobility. Two unused implants were used as a control group. All implant surfaces were examined by scanning electron microscopy (SEM) and energy-dispersive spectrometer x-ray (EDS) to element analysis. Evaluations were performed on several locations of the same implant.Results: SEM showed that the surface of all retrieved implants consisted of different degrees of organic residues, appearing mainly as dark stains. The surface topography presented as grooves and ridges along the machined surface similar to control group. Overall, foreign elements such as carbon, oxygen, sodium, calcium, silicon, and aluminum were detected in failed implants. The implants from control group presented no macroscopic contamination and clear signs of titanium.Conclusion: These preliminary results do not suggest any material-related cause for implant failures, although different element composition was assessed between failed implants and control implants.

Crystallization and preliminary X-ray diffraction analysis of importin-alpha acomplexed with NLS peptidomimetics

Importin-alpha is the nuclear import receptor that recognizes cargo proteins with nuclear localization sequences (NLSs). Tile study of NLS peptidomimetics can provide a better understanding of the requirements for the molecular recognition of cargo proteins by importin-alpha, and potentially engender a large number of applications in medicine. Importin-a was crystallized with a set of six NLS peptidomimetics, and X-ray diffraction data were collected in the range 2.1-2.5 angstrom resolution. Preliminary electron density calculations show that the ligands are present in the crystals. (c) 2005 Elsevier B.V All rights reserved.

Crystallization and preliminary X-ray diffraction analysis of a myotoxic phospholipase A(2) homologue from Bothrops neuwiedi pauloensis venom

Crystals of a myotoxic phospholipase A(2) from Bothrops neuwiedi pauloensis have been obtained. They diffracted at 2.5 Angstrom resolution using a synchrotron radiation source and belong to space group P3(1)21. Preliminary analysis shows that there are two molecules in the asymmetric unit. (C) 1999 Elsevier B.V. B.V. All rights reserved.

Crystallization and preliminary X-ray diffraction analysis of an acidic phospholipase A(2) complexed with p-bromophenacyl bromide and alpha-tocopherol inhibitors at 1.9-and 1.45-A resolution

An acidic phospholipase A(2) (PLA(2)) isolated from Bothrops jararacussu snake venom was crystallized with two inhibitors: alpha-tocopherol (vitamin E) and p-bromophenacyl bromide (BPB). The crystals diffracted at 1.45- and 1.85-Angstrom resolution, respectively, for the complexes with alpha-tocopherol and p-bromophenacyl bromide. The crystals are not isomorphous with those of the native protein, suggesting the inhibitors binding was successful and changes in the quaternary structure may have occurred. (C) 2004 Elsevier B.V. All rights reserved.

Crystallization and preliminary X-ray diffraction analysis of a myotoxic Lys49-PLA(2) from Bothrops jararacussu venom complexed with p-bromophenacyl bromide

For the first time, a non-catalytic and myotoxic Lys49-PLA(2) (BthTX-I from Bothrops jararacussu venom) has been crystallized with BPB inhibitor. X-ray diffraction data were collected and electron-density calculations showed that the ligand is bound to the His48 residue. BthTX-I with His48 chemically modified by BPB shows strongly reduced myotoxic and cytotoxic activities. This suggests a biological correlation between the modification of His48, which is associated with catalytic activity of PLA(2)s, and other toxicological activities of Lys49-PLA(2)s.

Preliminary X-ray crystallographic studies of BthTX-II, a myotoxic Asp49-phospholipase A(2) with low catalytic activity from Bothrops jararacussu venom

For the first time, a complete X-ray diffraction data set has been collected from a myotoxic Asp49-phospholipase A(2) (Asp49-PLA(2)) with low catalytic activity (BthTX-II from Bothrops jararacussu venom) and a molecular-replacement solution has been obtained with a dimer in the asymmetric unit. The quaternary structure of BthTX-II resembles the myotoxin Asp49-PLA(2) PrTX-III (piratoxin III from B. pirajai venom) and all non-catalytic and myotoxic dimeric Lys49-PLA(2)s. In contrast, the oligomeric structure of BthTX-II is different from the highly catalytic and non-myotoxic BthA-I (acidic PLA(2) from B. jararacussu). Thus, comparison between these structures should add insight into the catalytic and myotoxic activities of bothropic PLA(2)s.

Preliminary X-ray crystallographic studies of a tetrameric phospholipase A(2) formed by two isoforms of crotoxin B from Crotalus durissus terrificus venom

Crotoxin B is a basic phospholipase A(2) found in the venom of Crotalus durissus terrificus and is one of the subunits that constitute crotoxin. This heterodimeric toxin, which is the main component of C. d. terrificus venom, is completed by an acidic, nontoxic and non-enzymatic component (crotoxin A) and is involved in important envenomation effects, such as neurological disorders, myotoxicity and renal failure. Although crotoxin was first crystallized in 1938, no crystal structure is currently available for crotoxin, crotoxin A or crotoxin B. In this work, the crystallization, X-ray diffraction data collection to 2.28 angstrom resolution and molecular-replacement solution of a novel tetrameric complex formed by two dimers of crotoxin B isoforms (CB1 and CB2) is presented.