Electrogenerated chemiluminescence from luminol-labelled microbeads triggered by in situ generation of hydrogen peroxide.

We developed a sensing strategy that mimics the bead-based electrogenerated chemiluminescence immunoassay. However, instead of the most common metal complexes, such as Ru or Ir, the luminophore is luminol. The electrogenerated chemiluminescence of luminol was promoted by in situ electrochemical generation of hydrogen peroxide at a boron-doped diamond electrode. The electrochemical production of hydrogen peroxide was achieved in a carbonate solution by an oxidation reaction, while at the same time, microbeads labelled with luminol were deposited on the electrode surface. For the first time, we proved that was possible to obtain light emission from luminol without its direct oxidation at the electrode. This new emission mechanism is obtained at higher potentials than the usual luminol electrogenerated chemiluminescence at 0.3-0.5 V, in conjunction with hydrogen peroxide production on boron-doped diamond at around 2-2.5 V (vs Ag/AgCl).

Unveiling the promising anticancer activity of palladium(II)-aryl complexes bearing diphosphine ligands: a structure-activity relationship analysis.

In continuation of our previous works on the cytotoxic properties of organopalladium compounds, in this contribution we describe the first systematic study of the anticancer activity of Pd(II)-aryl complexes. To this end, we have prepared and thoroughly characterized a wide range of palladium derivatives bearing different diphosphine, aryl and halide ligands, developing, when necessary, specific synthetic protocols. Most of the synthesized compounds showed remarkable cytotoxicity towards ovarian and breast cancer cell lines, with IC50 values often comparable to or lower than that of cisplatin. The most promising complexes ([PdI(Ph)(dppe)] and [PdI(p-CH3-Ph)(dppe)]), characterized by a diphosphine ligand with a low bite angle, exhibited, in addition to excellent cytotoxicity towards cancer cells, low activity on normal cells (MRC5 human lung fibroblasts). Specific immunofluorescence tests (cytochrome c and H2AX assays), performed to clarify the possible mechanism of action of this class of organopalladium derivatives, seemed to indicate DNA as the primary cellular target, whereas caspase 3/7 assays proved that the complex [PdI(Ph)(dppe)] was able to promote intrinsic apoptotic cell death. A detailed molecular docking analysis confirmed the importance of a diphosphine ligand with a reduced bite angle to ensure a strong DNA-complex interaction. Finally, one of the most promising complexes was tested towards patient-derived organoids, showing promising ex vivo cytotoxicity.

Rosuvastatin effect on atherosclerotic plaque metabolism: A subclinical atherosclerosis imaging study with 18F-NaF PET-CT.

BACKGROUND AND AIMS: Atherosclerotic plaque fluorine-18 sodium fluoride (18F-NaF) uptake on positron emission tomography with computed tomography (PET-CT) identifies active microcalcification and has been shown to correlate with clinical instability in patients with cardiovascular (CV) disease. Statin therapy promotes coronary macrocalcification over time. Our aim was to investigate rosuvastatin effect on atheroma 18F-NaF uptake. METHODS: Subjects with high CV risk but without CV events underwent 18F-NaF-PET-CT in a single-centre. Those with subclinical atherosclerosis and significant 18F-NaF plaque uptake were included in a single-arm clinical trial, treated with rosuvastatin 20 mg/daily for six months, and re-evaluated by 18F-NaF-PET-CT. Primary endpoint was reduction in maximum atheroma 18F-NaF uptake in the coronary, aortic or carotid arteries, assessed by the tissue-to-background ratio (TBR). The secondary endpoint was corrected uptake per lesion (CUL) variation. RESULTS: Forty individuals were enrolled and 38 included in the pharmacological trial; mean age was 64 years, two-thirds were male and most were diabetic. The 10-year expected CV risk was 9.5% (6.0-15.3) for SCORE2 and 31.7 ± 18.7% for ASCVD systems. After six months of rosuvastatin treatment (n = 34), low-density lipoprotein cholesterol lowered from 133.6 ± 33.8 to 58.8 ± 20.7 mg dL-1 (60% relative reduction, p < 0.01). There was a significant 19% reduction in maximum plaque 18F-NaF uptake after treatment, from 1.96 (1.78-2.22) to 1.53 (1.40-2.10), p < 0.001 (primary endpoint analysis). The secondary endpoint CUL was reduced by 23% (p = 0.003). CONCLUSION: In a single-centre non-randomized clinical trial of high CV risk individuals with subclinical atherosclerosis, the maximum atherosclerotic plaque 18F-NaF uptake was significantly reduced after six months of high-intensity statin.

Redox-mediated electrochemiluminescence enhancement for bead-based immunoassay.

Electrochemiluminescence (ECL) is a highly sensitive mode of detection utilised in commercialised bead-based immunoassays. Recently, the introduction of a freely diffusing water-soluble Ir(iii) complex was demonstrated to enhance the ECL emission of [Ru(bpy)3]2+ labels anchored to microbeads, but a comprehensive investigation of the proposed 'redox-mediated' mechanism was not carried out. In this work, we select three different water-soluble Ir(iii) complexes by virtue of their photophysical and electrochemical properties in comparison with those of the [Ru(bpy)3]2+ luminophore and the TPrA co-reactant. A systematic investigation of the influence of each Ir(iii) complex on the emission of the Ru(ii) labels on single beads by ECL microscopy revealed that the heterogeneous ECL can be finely tuned and either enhanced up to 107% or lowered by 75%. The variation of the [Ru(bpy)3]2+ ECL emission was correlated to the properties of each Ir(iii)-based mediator, which enabled us to decipher the mechanism of interaction and define guidelines for the future design of novel Ir(iii) complexes to further enhance the ECL emission of bead-based immunoassays. Ultimately, we showcase the potential of this technology for practical sample analysis in commercial instruments by assessing the enhancement of the collective ECL intensity from a bead-based system.

High sensitivity troponins: A potential biomarkers of cardiovascular risk for primary prevention.

There have been several approaches to building charts for CV risk, all of which have both strengths and limitations. Identifying early organ damage provides relevant information and should be included in risk charts, although the direct relationship with risk is imprecise, variability between operators at the time to assess, and low availability in some healthcare systems, limits its use. Biomarkers, like troponin (cTns) isoforms cTnI and cTnT, a cardiac specific myocyte injury marker, have the great advantage of being relatively reproducible, more readily accessible, and applicable to different populations. New and improved troponin assays have good analytical performance, can measure very low levels of circulating troponin, and have low intra individual variation, below 10 %. Several studies have analyzed the blood levels in healthy subjects and their predictive value for cardiovascular events in observational, prospective and post-hoc studies. All of them offered relevant information and shown that high sensitivity hs-cTnI has a place as an additional clinical marker to add to current charts, and it also reflects sex- and age-dependent differences. Although few more questions need to be answered before recommend cTnI for assessing CV risk in primary prevention, seems to be a potential strong marker to complement CV risk charts.

Boron-Doped Diamond Electrode Outperforms the State-of-the-Art Electrochemiluminescence from Microbeads Immunoassay.

Electrochemiluminescence (ECL) is a powerful transduction technique where light emission from a molecular species is triggered by an electrochemical reaction. Application to biosensors has led to a wide range of electroanalytical methods with particular impact on clinical analysis for diagnostic and therapeutic monitoring. Therefore, the quest for increasing the sensitivity while maintaining reproducible and easy procedures has brought investigations and innovations in (i) electrode materials, (ii) luminophores, and (iii) reagents. Particularly, the ECL signal is strongly affected by the electrode material and its surface modification during the ECL experiments. Here, we exploit boron-doped diamond (BDD) as an electrode material in microbead-based ECL immunoassay to be compared with the approach used in commercial instrumentation. We conducted a careful characterization of ECL signals from a tris(2,2'-bipyridine)ruthenium(II) (Ru(bpy)32+)/tri-n-propylamine (TPrA) system, both homogeneous (i.e., free diffusing Ru(bpy)32+) and heterogeneous (i.e., Ru(bpy)32+ bound on microbeads). We investigated the methods to promote TPrA oxidation, which led to the enhancement of ECL intensity, and the results revealed that the BDD surface properties greatly affect the ECL emission, so it does the addition of neutral, cationic, or anionic surfactants. Our results from homogeneous and heterogeneous microbead-based ECL show opposite outcomes, which have practical consequences in ECL optimization. In conclusion, by using Ru(bpy)32+-labeled immunoglobulins bound on microbeads, the ECL resulted in an increase of 70% and a double signal-to-noise ratio compared to platinum electrodes, which are actually used in commercial instrumentation for clinical analysis. This research infers that microbead-based ECL immunoassays with a higher sensitivity can be realized by BDD.

Chemoselective oxidative addition of vinyl sulfones mediated by palladium complexes bearing picolyl-N-heterocyclic carbene ligands.

The manifold interactions of (E)- or (Z)-1,2-ditosylethene with a palladium(0) centre bearing picolyl-NHC carbene ligands have been studied thoroughly. (E)-1,2-Ditosylethene produces the expected and stable η2-olefin palladium complexes, whereas the coordination of the Z derivative alternatively promotes the isomerization of the olefin itself or an oxidative addition process depending on the steric bulkiness of carbene substituents and/or the adopted synthetic procedure. Remarkably, the oxidative addition pathway involves a selective S-vinyl (not S-aryl) breaking and produces selectively the S- rather than O-coordinated sulfinate. A mechanistic study has clarified the reasons of the chemoselectivity of the process, which was proved to be kinetically controlled. All the involved species have been isolated and exhaustively characterized. In particular, we report the first example of the X-ray crystal structure of a complex bearing one vinyl and one S-sulfinate fragment coordinated to palladium.

Synthesis of new allyl palladium complexes bearing purine-based NHC ligands with antiproliferative and proapoptotic activities on human ovarian cancer cell lines.

A series of new palladium allyl complexes bearing purine-based carbenes derived from caffeine, theophylline and theobromine have been prepared and characterized by NMR spectroscopy, and elemental analysis and in two cases by single crystal X-ray diffraction. The cytotoxic and proapoptotic activities of compounds have been determined in vitro on human ovarian cancer A2780 and SKOV-3 cell lines. These experiments have shown that the palladium-allyl fragment induces a general cytotoxicity, but the choice of the supporting ligands is of paramount importance for achieving the best results. In particular complexes 4c, 4d and 5d exhibit a higher antiproliferative effect (IC50: 0.09, 0.81 and 0.85 µM respectively) than cisplatin (IC50: 1.5 µM) on A2780 cells, and 4d (IC50: 1.7 µM vs. 5.94 µM) on SKOV-3 cell line. Moreover in many cases it has been proved that the cytotoxicity of our complexes is associated with the induction of apoptosis.

Reactivity of N-heterocyclic carbene-pyridine palladacyclopentadiene complexes toward halogen addition. The unpredictable course of the reaction.

As an extension of a previously published work we have reacted some palladacyclopentadiene complexes stabilized by bidentate N-heterocyclic carbene-pyridine or monodentate N-heterocyclic carbene-pyridine and isocyanide ligands with the halogens I2 and Br2. All the bidentate and monodentate complexes react with halogens to give at first the expected σ-coordinated butadienyl fragment. However, two of the less hindered NHC carbene-pyridine bidentate butadienyl iodo derivatives undergo a further rearrangement and novel Pd(ii) complexes characterized by a ten term coordinative ring were isolated and characterized. In the most favorable case we were able to carry out the kinetics of rearrangement and measure its reaction rate. Moreover, we have surmised a plausible mechanism on the basis of a dedicated computational approach and in one case the surprising structure characterized by the ten term coordinative ring was resolved by X-ray diffraction.

Isocyanide insertion across the Pd-C bond of allenyl and propargyl palladium complexes bearing phosphoquinoline as a spectator ligand. Synthesis of a palladium complex bearing a coordinated cyclobutenyl fragment.

We have studied the insertion of p-toluenesulfonylmethyl isocyanide (TosMIC) on selected allenyl and propargyl complexes of palladium bearing diphenylphosphine quinoline as a spectator ligand. The fast process gives different products depending on the tautomer involved in the reaction. Thus, the unsubstituted allenyl species yields an insertion complex with the isocyanide coordinated between the metal and the first allenyl carbon. On the other hand, a mixture of phenyl substituted allenyl and propargyl palladium complexes yields a novel species characterized by a cyclo-butenyl fragment directly coordinated to palladium. The solid state structure of such a complex together with an exhaustive kinetic study of the whole process is reported.

The unexpected case of reactions of halogens and interhalogens with halide substituted Pd(ii) σ-butadienyl complexes.

We have experimentally studied and theoretically interpreted the addition under stoichiometric conditions of halogens or interhalogens to σ-butadienyl palladium complexes bearing the heteroditopic thioquinolines as spectator ligands. The observed reactions do not involve the expected extrusion of the butadienyl fragment but rather the unpredictable substitution of the halide coordinated to palladium and in some cases also of that bound to the terminal butadienyl carbon. We have explained this peculiar reactivity with a mechanistic hypothesis based on a sequence of selective processes of oxidative addition and reductive elimination involving Pd(iv) intermediates.

[Satisfação com o Internato Médico em Portugal]. / Satisfação com o Internato Médico em Portugal.

INTRODUCTION: In the last years, the global context of medical education and Medical Residency programs in Portugal suffered substantial changes. The primary objective of this study was to evaluate and characterize medical residents ́ satisfaction with medical residency programs in Portugal and to identify features that could be improved. MATERIAL AND METHODS: We utilized as model the survey Postgraduate Hospital Educational Environment Measure that has been developed in the United Kingdom and is speci cally targeted to medical residents. The survey was translated and adapted to the Portuguese reality. The survey was available online during April and May of 2016. RESULTS: A total of 3456 responses were obtained, corresponding to a response rate of 35%. Endocrinology/Nutrition, Cardiology, Anesthesiology, Family Physician and Gastroenterology were the specialties in which the degree of satisfaction was higher, while Forensic Medicine, Medical Oncology, Internal Medicine, General Surgery and Pneumology showed the lowest level of satisfaction. DISCUSSION: This study presented a high response rate when compared to previous studies. Portuguese medical residents presented high levels of satisfaction. Depending on year of medical residency, region, type of specialty and type of hospital marked asymmetries were noticed. CONCLUSION: The survey ́s results should constitute in the future a support tool for the implementation of local and national measures relating to the medical residency. It is advisable to regularly conduct satisfaction surveys to medical residents.

Introdução: Nos últimos anos, o contexto global da formação médica, e em particular do Internato Médico em Portugal, sofreu profundas alterações. O presente estudo teve como objetivo avaliar e caracterizar a satisfação dos médicos internos com a realização do Internato Médico em Portugal e identificar aspetos passíveis de melhoria.Material e Métodos: Foi utilizado como modelo de inquérito o questionário Postgraduate Hospital Educational Environment Measuredesenvolvido no Reino Unido e dirigido a médicos internos, o qual foi traduzido e adaptado à realidade portuguesa. O questionário esteve disponível online durante os meses de abril e maio de 2016.Resultados: Foram obtidas 3456 respostas, correspondendo a uma taxa de resposta de 35%. Endocrinologia/Nutrição, Cardiologia, Anestesiologia, Medicina Geral e Familiar e Gastrenterologia foram as especialidades nas quais o grau de satisfação foi mais elevado,enquanto que Medicina Legal, Oncologia Médica, Medicina Interna, Cirurgia Geral e Pneumologia apresentaram o grau de satisfaçãomais baixo.Discussão: O presente estudo apresenta uma elevada taxa de resposta comparativamente com estudos prévios. A nível nacional, no global, os médicos internos apresentaram níveis elevados de satisfação, destacando-se marcadas assimetrias de acordo com o ano de especialidade, região, tipologia de instituição e de especialidade.Conclusão: Os resultados deste inquérito poderão constituir uma ferramenta de apoio à implementação de medidas de âmbito local enacional relacionadas com o Internato Médico, sendo desejável a realização regular de inquéritos de satisfação aos médico internos.

The addition of bromine and iodine to palladacyclopentadienyl complexes bearing bidentate heteroditopic P-N spectator ligands derived from differently substituted quinolinic frames. The unexpected evolution of the reaction.

We have synthesized two palladacyclopentadienyl derivatives bearing bidentate ligands heteroditopic 8-(diphenylphosphino)quinoline or 8-(diphenylphosphino)-2-methylquinoline. We have reacted the palladacyclopentadienyl complexes with Br2 and I2 to gain clues on the formation mechanism of the corresponding σ-butadienyl derivatives. We were able to obtain the pure σ-butadienyl derivative only in the case of Br2 reacting with the palladacyclopentadienyl complex bearing the unsubstituted quinoline. However, an equilibrium mixture of the σ-butadienyl and a novel zwitterionic species was obtained when the same complex reacts with I2. Furthermore, we have obtained exclusively an unprecedented zwitterionic complex when I2 reacts with the palladacyclopentadienyl complex bearing the substituted quinoline and a different ratio of an equilibrium mixture of σ-butadienyl and the zwitterionic species when the latter derivative reacts with Br2. The solid state structures of one σ-butadienyl complex and of the two novel zwitterionic derivatives were determined and an interpretation of the observed reactivity based on kinetic data and a computational study has been suggested.

Substitution reactions between bis-chelate ligands in palladium(II) alkenyl complexes: an unusual way to form unstable trans-P complexes. A study on the isomerization mechanism.

The substitution reactions between asymmetric bis-chelate ligands and alkenyl chloro derivatives of palladium(II) of the type [Pd(L-L')(Rx)Cl] (L-L' = 2-phenylsulfanylmethyl-pyridine (HN-SPh), 2-methyl-6-phenylsulfanylmethyl-pyridine (MeN-SPh), 2,2'-bipyridinyl (BiPy), Rx = -CCOOMe=CMeCOOMe (Ra), -CCOOEt=CMeCOOEt (Rb), -CCOOt-Bu=CMeCOOt-Bu (Rc), -(CCOOMe=CCOOMe)(2)Me (Rd)) with phosphoquinoline moieties (8-diphenylphosphanyl-quinoline (DPPQ), 8-diphenylphosphanyl-2-methyl-quinoline (DPPQ-Me)) usually leads to the formation of the stable geometrical isomer bearing these groups in the cis position thanks to the mutual trans influence of the alkenyl and phosphine groups. However, when the leaving group MeN-SPh and the entering ligand DPPQ are involved, the fast and quantitative substitution reaction leads to the formation of a couple of geometrical isomers [Pd(DPPQ)(Rx)Cl]-trans P and [Pd(DPPQ)(Rx)Cl]-cis P (Rx = Ra, Rb, Rc, Rd) in which the alkenyl and the phosphine groups are in mutual trans or cis position. The substrate [Pd(DPPQ)(Rx)Cl]-trans P (Rx = Ra, Rb, Rc) slowly interconverts into its thermodynamically stable -cis P counterpart while the bulky [Pd(DPPQ)(Rd)Cl]-trans P displays no tendency to isomerize, thereby allowing separation of the two geometrical forms. Also, the ligand DPPQ-Me induces the formation of the -trans P geometrical isomer which is only detectable at low temperature since it rapidly interconverts into the -cis P derivative at RT. The kinetics of the interconversion process, a reasonable explanation of the observed phenomenon based on theoretical calculations, and eventually an unequivocal structure determination of the stable [Pd(DPPQ)(Rx)Cl]-cis P substrate are reported in the present paper.