31 research outputs found

    One century of photography and preservation in Catalonia: the Service for Local Architectural Heritage (SPAL)

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    The Service for the Cataloguing and Preservation of Architectonic Monuments was created by the Provincial Government of Barcelona the same year as the constitution of the Regional Government of Catalonia called Mancomunitat (1914-1925). Both establishments, Diputació and Mancomunitat, were presided over by Enric Prat de la Riba, one of the most charismatic politicians of his time in Catalonia and in Spain. This Architectural Service was created just one hundred years ago, on 9th June 1914, and was a consequence of the “Report for the Preservation and Cataloguing of Monuments” produced by the Catalan Studies Institute, the academic entity responsible for all matters related to Catalan culture from its foundation in 1907

    Synthesis, characterization and biological activity of new cyclometallated platinum(IV) complexes containing a para-tolyl ligand

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    The synthesis of three new cyclometallated platinum(II) compounds containing a para-tolyl ligand and a tridentate [C,N,N'] (cm1) or a bidentate [C,N] ligand and an additional ligand such as SEt2 (cm2) or Ph3 (cm3) is reported. The X-ray molecular structure of platinum(II) compound cm3 is also presented. Intermolecular oxidative addition of methyl iodide or iodine upon cm1, cm2 and cm3 produced six novel cyclometallated platinum(IV) compounds. The cytotoxic activity against a panel of human adenocarcinoma cell lines (A-549 lung, MDA-MB-231 and MCF-7 breast, and HCT-116 colon), DNA interaction, topoisomerase I, IIα, and cathepsin B inhibition, and cell cycle arrest, apoptosis and ROS generation of the investigated complexes are presented. The best results for antiproliferative activity were obtained for platinum (IV) compounds cm1MeI and cm1I2 arising from oxidative addition of methyl iodide and iodine, respectively, to cm1. Cyclometallated platinum(IV) compounds cm1MeI and cm3MeI induce significant changes in the mobility of DNA and, in addition, cm1MeI, cm3MeI and cm1I2, showed considerable topoisomerase IIα inhibitory activity. Moreover, the compounds exhibiting the higher antiproliferative activity (cm1MeI and cm1I2) were found to generate ROS and to supress HCT-116 colon cancer cell growth by a mixture of cell cycle arrest and apoptosis induction. 1H NMR experiments carried out in a buffered aqueous medium (pH 7.40) indicate that compound cm1MeI is not reduced by common biologically relevant reducing agents such as ascorbic acid, glutathione or cysteine

    Heteroclinic intersections between Invariant Circles of Volume-Preserving Maps

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    We develop a Melnikov method for volume-preserving maps with codimension one invariant manifolds. The Melnikov function is shown to be related to the flux of the perturbation through the unperturbed invariant surface. As an example, we compute the Melnikov function for a perturbation of a three-dimensional map that has a heteroclinic connection between a pair of invariant circles. The intersection curves of the manifolds are shown to undergo bifurcations in homologyComment: LaTex with 10 eps figure

    A study of the properties, reactivity and anticancer activity of novel N- methylated-3-thiazolyl or 3-thienyl carbazoles and their Pd(II) and Pt(II) complexes

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    The synthesis and characterization of two hybrid N-methylated carbazole derivatives containing a thiazolyl or a thienyl ring is reported. The thiazolyl derivative has been also characterised by X-ray diffraction analysis. The study of its reactivity in front of [MCl2(dmso)(2)] (M = Pd or Pt) or Na-2[PdCl4] in methanol has allowed us to isolate and characterize its complexes. However, for the thienyl analogue, the formation of any Pd(II) or Pt(II) complex was not detected, indicating that it is less prone to bind to the M(II) ions than its thiazolyl analogue. Density Functional Theory (DFT) and Time-Dependent Density Functional Theory (TD-DFT) calculations have also been carried out in order to rationalize the influence of the nature of the thiazolyl or thienyl group on the electronic delocalization. Molecular mechanics calculations show that the free rotation of the thiazolyl in relation to the carbazole requires a greater energy income than for its thienyl analogue. Studies of the cytotoxic activity of the new compounds on colon (HCT116) and breast (MDA-MB231 and MCF7) cancer cell lines show that the thiazolyl carbazole ligand and its Pt(II) complex are the most active agents of the series and in the MCF7 line their potency is higher than that of cisplatin. In the non-tumoral human skin fibroblast BJ cell line, all the compounds were less toxic than cisplatin. Their potential ability to modify the electrophoretic mobility of pBluescript SK+ plasmid DNA and to act as inhibitors of Topoisomerases I and II alpha or cathepsin B has also been investigated

    Synthesis, characterization and biological activity of new cyclometallated platinum(IV) iodido complexes

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    The synthesis of six novel cyclometallated platinum(IV) iodido complexes is accomplished by intermolecular oxidative addition of methyl iodide (compounds 2a-2c) or iodine (compounds 3a-3c) upon cyclometallated platinum(II) compounds [PtX{(CH3)(2)N(CH2)(3)NCH(4-ClC6H3)}] (1a-1c: X = Cl, CH3 or I). The X-ray molecular structures of platinum(II) compound 1c and platinum(IV) compounds 3b and 3a' (an isomer of 3a) are reported. The cytotoxic activity against a panel of human adenocarcinoma cell lines (A-549 lung, MDA-MB-231 and MCF-7 breast, and HCT-116 colon), DNA interaction, topoisomerase I, II alpha, and cathepsin B inhibition, and cell cycle arrest, apoptosis and ROS generation of the investigated complexes are presented. Remarkable antiproliferative activity was observed for most of the synthesized cycloplatinated compounds (series 1-3) in all the selected carcinoma cell lines. The best inhibition was provided for the octahedral platinum(IV) compounds 2a-2c exhibiting a methyl and an iodido axial ligand. Preliminary biological results point to a different mechanism of action for the investigated compounds. Cyclometallated platinum(II) compounds 1a-1c modify the DNA migration as cisplatin. In contrast, cyclometallated platinum(IV) compounds 2a-2c and 3a-3c did not modify the DNA tertiary structure neither in the absence nor in the presence of ascorbic acid, which made them incapable of reducing platinum(IV) compounds 2b and 2c in a buffered aqueous medium (pH 7.40) according to H-1 NMR experiments. Remarkable topoisomerase II alpha inhibitory activity is reported for platinum(IV) complexes 2b and 3a and in addition, for the last one, a moderate cathepsin B inhibition is reported. Cell cycle arrest (decrease in G0/G1 and G2 phases and arrest in the S phase), induction of apoptosis and ROS generation are related to the antiproliferative activity of some representative octahedral cyclometallated platinum(IV) compounds (2b and 2c)

    Luminescent Pt-II and Pt-IV Platinacycles with Anticancer Activity Against Multiplatinum-Resistant Metastatic CRC and CRPC Cell Models

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    Platinum-based chemotherapy persists to be the only effective therapeutic option against a wide variety of tumours. Nevertheless, the acquisition of platinum resistance is utterly common, ultimately cornering conventional platinum drugs to only palliative in many patients. Thus, encountering alternatives that are both effective and non-cross-resistant is urgent. In this work, we report the synthesis, reduction studies, and luminescent properties of a series of cyclometallated (C,N,N')PtIV compounds derived from amine- imine ligands, and their remarkable efficacy at the high nanomolar range and complete lack of cross57 resistance, as an intrinsic property of the platinacycle, against multiplatinum-resistant colorectal cancer (CRC) and castration-resistant prostate cancer (CRPC) metastatic cell lines generated for this work. We have also determined that the compounds are effective and selective for a broader cancer panel, including breast and lung cancer. Additionally, selected compounds have been further evaluated, finding a shift in their antiproliferative mechanism towards more cytotoxic and less cytostatic than cisplatin against cancer cells, being also able to oxidize cysteine residues and inhibit topoisomerase II, thereby holding great promise as future improved alternatives to conventional platinum drugs

    Cyclopalladated Benzophenone Imines: Synthesis, Antitumor Activity, Cell Accumulation, DNA Interaction, and Cathepsin B Inhibition.

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    The synthesis of the endo five-membered cyclo-ortho-palladated benzophenone imines [Pd{C6H4(Ph)C═NR}]2(ÎŒ-X)2 [1 (X = OAc), 2 (X = Cl), a (R = phenyl), b (R = 1-naphthyl), c (R = benzyl), d (R = α-methylbenzyl)], and trans-N,P-[Pd{C6H4(Ph)C═NR}X(PPh3)] [3 (X = OAc), 4 (X = Cl), a (R = phenyl), b (R = 1-naphthyl), c (R = benzyl), d (R = α-methylbenzyl)] and the X-ray molecular structure of 1a, 1c, 1d, 4a, 4b, and 4c are reported. The antitumor activity, DNA interaction, and cathepsin B inhibition of palladium compounds a-d were studied and compared with those previously reported for palladium compounds e with R = H and compound 4f analogous to 4e but with a platinum(II) center. The IC50 values against a panel of human cancer cell lines allowed the establishment of a qualitative relationship between their structure and antitumor activity. Compounds 3e, 4e, and 4f were the most active ones in relation to their in vitro anticancer activity. Compounds 3e and 4e were about 4 times more active than cisplatin against the MDA-MB-231 and MCF-7 breast human cancer lines, and compound 4f was about 4 times more active than cisplatin against the cisplatin-resistant HCT-116 colon human cancer cell line. In addition, compound 3e was 3 times less cytotoxic than cisplatin toward the quiescent HUVEC cells. Accumulation of palladium compounds e and b in the MDA-MB-231 cell line was considerably greater than that of cisplatin in the same cell line, but palladium compounds b were noncytotoxic. Some of these complexes altered the DNA tertiary structure in a similar way to cisplatin but at higher concentration, and most cytotoxic ones did not present a high efficiency as cathepsin B inhibitors

    Exploring the scope of [Pt2(4-FC6H4)4(Ό-SEt2)2] as a precursor for new organometallic platinum(II) and platinum(IV) antitumor agents

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    The new compound [Pt2(4-FC6H4)4(ÎŒ-SEt2)2] (A) was prepared and fully characterized. The reactions of compound A with ligands ArCH=NCH2CH2NMe2 (Ar = 2-BrC6H4, 1a; 2,6-Cl2C6H3, 1b; 4-ClC6H4, 1c; 2-Cl,6-FC6H3, 1d) were studied under different conditions and produced platinum(II) compounds [Pt(4-FC6H4)2(ArCH=NCH2CH2NMe2)] (2b−2d), containing a bidentate [N,Nâ€Č] ligand, as well as cyclometalated platinum(IV) or platinum(II) compounds such as [PtBr(4-FC6H4)2(C6H4CH=NCH2CH2NMe2)] (4a) or [PtCl{(3-FC6H3)(2-XC6H3)CH=NCH2CH2NMe2}] (5b: X = Cl; 5d: X = F), containing a tridentate [C,N,Nâ€Č] ligand and either a five (4a) or a seven (5b, 5d) membered metallacycle. These compounds exhibit a great antiproliferative activity against non-small lung cancer cells (A549), and the best result was obtained for compound 2c (IC50 = 0.3 ± 0.1 ÎŒM). While compounds 5 alter the mobility of plasmid DNA in a similar way to cisplatin, compound 4 was less efficient in removing the supercoils from DNA. In spite of the very low IC50 value obtained for compound 2c, this compound does not interact with DNA, and it is neither an intercalator nor a topoisomerase I inhibitor

    Platinum (II) and palladium (II) complexes with (N,N') and (C,N,N') ligands derived from pyrazole as anticancer and antimalarial agents: synthesis, characterization and in vitro activities

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    The study of the reactivity of three 1-(2-dimethylaminoethyl)-1H-pyrazole derivatives of general formula [1-(CH2)2NMe2}-3,5-R2-pzol] {where pzol represents pyrazole and Rdouble bond; length as m-dashH (1a), Me (1b) or Ph (1c)} with [MCl2(DMSO)2] (Mdouble bond; length as m-dashPt or Pd) under different experimental conditions allowed us to isolate and characterize cis-[M{Îș2-N,Nâ€Č-{[1-(CH2)2NMe2}-3,5-R2-pzol])}Cl2] {MMdouble bond; length as m-dashPtPt (2a-2c) or Pd (3a-3c)} and two cyclometallated complexes [M{Îș3-C,N,Nâ€Č-{[1-(CH2)2NMe2}-3-(C5H4)-5-Ph-pzol])}Cl] {Mdouble bond; length as m-dashPt(II) (4c) or Pd(II) (5c)}. Compounds 4c and 5c arise from the orthometallation of the 3-phenyl ring of ligand 1c. Complex 2a has been further characterized by X-ray crystallography. Ligands and complexes were evaluated for their in vitro antimalarial against Plasmodium falciparum and cytotoxic activities against lung (A549) and breast (MDA MB231 and MCF7) cancer cellular lines. Complexes 2a-2c and 5c exhibited only moderate antimalarial activities against two P. falciparum strains (3D7 and W2). Interestingly, cytotoxicity assays revealed that the platinacycle 4c exhibits a higher toxicity than cisplatin in the three human cell lines and that the complex 2a presents a remarkable cytotoxicity and selectivity in lung (IC50 = 3 ÎŒM) versus breast cancer cell lines (IC50 > 20 ÎŒM). Thus, complexes 2c and 4c appear to be promising leads, creating a novel family of anticancer agents. Electrophoretic DNA migration studies in presence of the synthesized compounds have been performed, in order to get further insights into their mechanism of action

    Neutral and ionic platinum compounds containing a cyclometalated chiral primary amine: Synthesis, antitumor activity, DNA interaction and topoisomerase I - cathepsin B inhibition

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    The synthesis and preliminary biological evaluation of neutral and cationic platinum derivatives of chiral 1-(1-naphthyl)ethylamine are reported, namely cycloplatinated neutral complexes [PtCl{(R or S)-NH(2)CH(CH(3))C(10)H(6)}(L)] [L = SOMe(2) ( 1-R or 1-S ), L = PPh(3) (2-R or 2-S), L = P(4-FC(6)H(4))(3) (3-R), L = P(CH(2))(3)N(3)(CH(2))(3) (4-R)], cycloplatinated cationic complexes [Pt{(R)-NH(2)CH(CH(3))C(10)H(6)}{L}]Cl [L = Ph(2)PCH(2)CH(2)PPh(2) (5-R), L = (C(6)F(5))(2)PCH(2)CH(2)P(C(6)F(5))(2) (6-R)] and the Pt(ii) coordination compound trans-[PtCl(2){(R)-NH(2)CH(CH(3))C(10)H(6)}(2)] (7-R). The X-ray molecular structure of 7-R is reported. The cytotoxic activity against a panel of human adenocarcinoma cell lines (A-549 lung, MDA-MB-231 and MCF-7 breast, and HCT-116 colon), cell cycle arrest and apoptosis, DNA interaction, topoisomerase I and cathepsin B inhibition, and Pt cell uptake of the studied compounds are presented. Remarkable cytotoxicity was observed for most of the synthesized Pt(ii) compounds regardless of (i) the absolute configuration R or S, and (ii) the coordinated/cyclometallated (neutral or cationic) nature of the complexes. The most potent compound 2-R (IC(50) = 270 nM) showed a 148-fold increase in potency with regard to cisplatin in HCT-116 colon cancer cells. Preliminary biological results point out to different biomolecular targets for the investigated compounds. Neutral cyclometallated complexes 1-R and 2-R, modify the DNA migration as cisplatin, cationic platinacycle 5-R was able to inhibit topoisomerase I-promoted DNA supercoiling, and Pt(ii) coordination compound 7-R turned out to be the most potent inhibitor of cathepsin B. Induction of G-1 phase ( 2-R and 5-R ), and S and G-2 phases (6-R) arrests are related to the antiproliferative activity of some representative compounds upon A-549 cells. Induction of apoptosis is also observed for 2-R and 6-R
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