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Unprecedented one-pot synthesis of an unsymmetrical cisplatin-based Pt(iv)-acetamidato complex
No full textWe describe herein a novel Pt(iv)-acetamidato complex as a result of the one-pot reaction between cisplatin and the highly reactive peroxyacetimidic acid generated in situ. This is the first example of a Pt(iv) complex containing a N-donor ligand coordinated during the Pt(ii) → Pt(iv) oxidation step. Remarkably, the Pt(iv)-amidato compound is highly soluble and stable in water; it represents an interesting building block for the further development of Pt(iv) antitumor prodrugs
Application of microwave-assisted heating to the synthesis of Pt(II) complexes
No full textThe microwave-assisted synthesis of Pt(II) complexes containing several pyridines (i.e., pyridine L1, 2-picoline L2, 3-picoline L3, 4-picoline L4, 2,2′-bipyridine L5) is reported. For L1-L5, the reaction was successful in about 50% yield with all the ligands except L2. The same method applied to 4,4′-bis(2-morpholinoethoxy)-2,2′-bipyridine (L6, a ligand showing interesting antiproliferative properties because of a high DNA affinity), was unsatisfactory. The corresponding complex cis-[PtCl2(L6)] was obtained only heating at reflux a mixture of [PtCl2(1,5-cyclooctadiene)] and L6 in acetonitrile for 24 h. Antiproliferative activity of [PtCl2(L6)] on four cancer cell lines (ovarian A2780 and its cisplatin-resistant variant A2780cisR, prostate PC3 and breast cancer MDA-MB-231) was compared with that of its ligand and the model complex [PtCl2(L5)]. These studies showed that [PtCl2(L6)] has just marginal activity towards the tested cells if compared with cisplatin. © 2015 Elsevier B.V. All rights reserved
Going Beyond Counting First Authors in Author Co-citation Analysis
Get PDFThe present study examines one of the fundamental aspects of author co-citation analysis (ACA) - the way co-citation
counts are defined. Co-citation counting provides the data on which all subsequent statistical analyses and mappings
are based, and we compare ACA results based on two different types of co-citation counting - the traditional type that
only counts the first one among a cited work's authors on the one hand and a non-traditional type that takes into
account the first 5 authors of a cited work on the other hand. Results indicate that the picture produced through this non-traditional author co-citation counting contains more coherent author groups and is therefore considerably clearer. However, this picture represents fewer specialties in the research field being studied than that produced through the traditional first-author co-citation counting when the same number of top-ranked authors is selected and analyzed. Reasons for these effects are discussed
Antiproliferative activity of a series of cisplatin-based Pt(iv)-acetylamido/carboxylato prodrugs
Get PDFWe report studies of a novel series of Pt(IV) complexes exhibiting an asymmetric combination of acetylamido
and carboxylato ligands in the axial positions. We demonstrate efficient synthesis of a series of analogues,
differing in the alkyl chain length and hence lipophilicity, from a stable acetylamido/hydroxido
complex formed by reaction of cisplatin with peroxyacetimidic acid (PAIA). NMR spectroscopy and X-ray
crystallography confirm the identity of the resulting complexes, and highlight subtle differences in the
structure and stability of acetylamido complexes compared to the equivalent acetato complexes.
Reduction of acetylamido complexes, whether achieved chemically or electro-chemically, is significantly
more difficult than that of acetate complexes, resulting in lower antiproliferative activity for shorter-chain
complexes. For those with longer chains and hence greater cell uptake, this difference is negated and
acetylamido complexes are as active as acetato analogues, both exhibiting antiproliferative potency
(1/IC50) against A2780 ovarian cancer cells similar to that of cisplatin
Variations on the Author
Get PDF“Variations on the Author” discusses two of Eduardo Coutinho’s recent films (Um Dia na Vida, from 2010, and Últimas Conversas, posthumously released in 2015) and their contribution to the general question of documentary authorship. The director’s filmography is characterized by a consistent yet self-effacing form of authorial self-inscription: Coutinho often features as an interviewer that rather than express opinions propels discourses; an interviewer that is good at listening. This mode of self-inscription characterizes him as an author who is not expressive but who is nonetheless markedly present on the screen. In Um Dia na Vida, however, Coutinho is completely absent form the image, while Últimas Conversas, on the contrary, includes a confessional prologue that moves the director from the margins to the center of his films. This article examines the ways in which these works stand out in the filmography of a director who offers new insights into the notion of cinematic authorship
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