202 research outputs found

    New insight into the structural, electrochemical and biological aspects of macrocylic Cu(II) complexes derived from S-substituted dithiocarbazate Schiff bases

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    Copper (II) complexes synthesized from the products of condensation of S-methyl- and S-benzyldithiocarbazate with 2,5-hexanedione (SMHDH2 and SBHDH2 respectively) have been characterized using various physicochemical (elemental analysis, molar conductivity, magnetic susceptibility) and spectroscopic (infrared, electronic) methods. The structures of SMHDH2, its copper (II) complex, CuSMHD, and the related CuSBHD complex as well as a pyrrole byproduct, SBPY, have been determined by single crystal X-ray diffraction. In order to provide more insight into the behaviour of the complexes in solution, electron paramagnetic resonance (EPR) and electrochemical experiments were performed. Antibacterial activity and cytotoxicity were evaluated. The compounds, dissolved in 0.5% and 5% DMSO, showed a wide range of antibacterial activity against 10 strains of Gram-positive and Gram-negative bacteria. Investigations of the effects of efflux pumps and membrane penetration on antibacterial activity are reported herein. Antiproliferation activity was observed to be enhanced by complexation with copper. Preliminary screening showed Cu complexes are strongly active against human breast adenocarcinoma cancer cell lines MDA-MB-231 and MCF-7

    Novel 8-nitroquinolin-2(1H)-ones as NTR-bioactivated antikinetoplastid molecules:Synthesis, electrochemical and SAR study

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    International audienceTo study the antiparasitic 8-nitroquinolin-2(1H)-one pharmacophore, a series of 31 derivatives was synthesized in 1-5 steps and evaluated in vitro against both Leishmania infantum and Trypanosoma brucei brucei. In parallel, the reduction potential of all molecules was measured by cyclic voltammetry. Structure-activity relationships first indicated that antileishmanial activity depends on an intramolecular hydrogen bond (described by X-ray diffraction) between the lactam function and the nitro group, which is responsible for an important shift of the redox potential (+0.3 V in comparison with 8-nitroquinoline). With the assistance of computational chemistry, a set of derivatives presenting a large range of redox potentials (from -1.1 to -0.45 V) was designed and provided a list of suitable molecules to be synthesized and tested. This approach highlighted that, in this series, only substrates with a redox potential above -0.6 V display activity toward L. infantum. Nevertheless, such relation between redox potentials and in vitro antiparasitic activities was not observed in T. b. brucei. Compound 22 is a new hit compound in the series, displaying both antileishmanial and antitrypanosomal activity along with a low cytotoxicity on the human HepG2 cell line. Compound 22 is selectively bioactivated by the type 1 nitroreductases (NTR1) of L. donovani and T. brucei brucei. Moreover, despite being mutagenic in the Ames test, as most of nitroaromatic derivatives, compound 22 was not genotoxic in the comet assay. Preliminary in vitro pharmacokinetic parameters were finally determined and pointed out a good in vitro microsomal stability (half-life > 40 min) and a 92% binding to human albumin

    8-Aryl-6-chloro-3-nitro-2-(phenylsulfonylmethyl)imidazo[1,2-a]pyridines as potent antitrypanosomatid molecules bioactivated by type 1 nitroreductases

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    Based on a previously identified antileishmanial 6,8-dibromo-3-nitroimidazo[1,2-a]pyridine derivative, a Suzuki-Miyaura coupling reaction at position 8 of the scaffold was studied and optimized from a 8-bromo-6-chloro-3-nitroimidazo[1,2-a]pyridine substrate. Twenty-one original derivatives were prepared, screened in vitro for activity against L infantum axenic amastigotes and T. brucei brucei trypomastigotes and evaluated for their cytotoxicity on the HepG2 human cell line. Thus, 7 antileishmanial hit compounds were identified, displaying IC50 values in the 1.1-3 mu M range. Compounds 13 and 23, the 2 most selective molecules (SI = >18 or >17) were additionally tested on both the promastigote and intramacrophage amastigote stages of L donovani. The two molecules presented a good activity (IC50 = 1.2-1.3 mu M) on the promastigote stage but only molecule 23, bearing a 4-pyridinyl substituent at position 8, was active on the intracellular amastigote stage, with a good IC50 value (2.3 mu M), slightly lower than the one of miltefosine (IC50 = 4.3 mu M). The antiparasitic screening also revealed 8 antitrypanosomal hit compounds, including 14 and 20, 2 very active (IC50 = 0.04-0.16 mu M) and selective (SI = >313 to 550) molecules toward T brucei brucei, in comparison with drug-candidate fexinidazole (IC50 = 0.6 & SI > 333) or reference drugs suramin and eflornithine (respective IC50 = 0.03 and 13.3 mu M). Introducing an aryl moiety at position 8 of the scaffold quite significantly increased the antitrypanosomal activity of the pharmacophore. Antikinetoplastid molecules 13, 14, 20 and 23 were assessed for bioactivation by parasitic nitroreductases (either in L donovani or in T. brucei brucei), using genetically modified parasite strains that over-express NTRs: all these molecules are substrates of type 1 nitroreductases (NTRI), such as those that are responsible for the bioactivation of fexinidazole. Reduction potentials measured for these 4 hit compounds were higher than that of fexinidazole (-0.83 V), ranging from -0.70 to -0.64 V

    New 8-nitroquinolinone derivative displaying submicromolar in vitro activities against both Trypanosoma brucei and cruzi

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    International audienceAn antikinetoplastid pharmacomodulation study was conducted at position 6 of the 8-nitroquinolin-2(1H)-one pharmacophore. Fifteen new derivatives were synthesized and evaluated in vitro against L. infantum, T. brucei brucei, and T. cruzi, in parallel with a cytotoxicity assay on the human HepG2 cell line. A potent and selective 6-bromo-substituted antitrypanosomal derivative 12 was revealed, presenting EC50 values of 12 and 500 nM on T. b. brucei trypomastigotes and T. cruzi amastigotes respectively, in comparison with four reference drugs (30 nM ≤ EC50 ≤ 13 μM). Moreover, compound 12 was not genotoxic in the comet assay and showed high in vitro microsomal stability (half life >40 min) as well as favorable pharmacokinetic behavior in the mouse after oral administration. Finally, molecule 12 (E° = −0.37 V/NHE) was shown to be bioactivated by type 1 nitroreductases, in both Leishmania and Trypanosoma, and appears to be a good candidate to search for novel antitrypanosomal lead compounds

    De las catacumbas a los últimos confines: violencia, sentido y representación en los periplos del martirio

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    En este trabajo propongo un análisis transversal de las figuras del mártir y del martirio. Recurriendo a la noción de mediación, en la primera parte analizo el rol protagónico de las representaciones del martirio en las prácticas de la memoria durante la segunda mitad del siglo XVI. Analizo algunas de las condiciones que contribuyeron a la emergencia de una "cultura del martirio" y el rol de las mediaciones en tal surgimiento. En la segunda parte, estudio la forma en que el (re)descubrimiento de las catacumbas romanas, abrió un campo de producción de sentido en torno a la figura del martirio. En la tercera parte, centrándome en la Compañía de Jesús, analizo algunas mediaciones a través de las cuáles las figuras del martirio transgredieron las fronteras de iglesias y conventos para proyectarse a los últimos confines en un mundo en plena expansión.Neste artigo proponho uma análise transversal das figuras do mártir e do martírio. Usando a noção de mediação, na primeira parte eu tento analisar o papel de liderança de representações de martírio em práticas de memória durante a segunda metade do século XVI. Eu analiso algumas das condições que contribuíram para o surgimento de uma "cultura do martírio" e o papel da mediação nesta emergência. Na segunda parte, eu estudo como a (re) descoberta das catacumbas romanas abriu um campo de produção de significados em torno da figura do martírio. Na terceira parte, com foco na Companhia de Jesus, analiso algumas mediações pelas quais as representações do martírio transgrediram as fronteiras de igrejas e conventos para se projetar nas fronteiras de um mundo em plena expansão mundial.This paper proposes a cross-sectional analysis of martyr and martyrdom. Through the notion of mediation, in the first part I analyze the leading role of representations of martyrdom in memory practices during the second half of the sixteenth century. I analyze some of the conditions that contributed to the emergence of a "martyrdom's culture" and the role of mediation in such emergence. The second part studies how the (re)discovery of the Roman catacombs encouraged the production of meanings around the figure of martyrdom. In the third part, focusing on the Society of Jesus, I analyze a few instances of mediation through which the figures of martyrdom transgressed the boundaries of churches and convents to project themselves to the last frontiers of a world in full expansion.Fil: Salamanca Villamizar, Carlos Arturo. Consejo Nacional de Investigaciones Científicas y Técnicas; Argentin

    Antikinetoplastid SAR study in 3-nitroimidazopyridine series:identification of a novel non-genotoxic and potent anti-T. b. brucei hit-compound with improved pharmacokinetic properties.

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    International audienceTo study the antikinetoplastid 3-nitroimidazo[1,2-a]pyridine pharmacophore, a structure-activity relationship study was conducted through the synthesis of 26 original derivatives and their in vitro evaluation on both Leishmania spp and Trypanosoma brucei brucei. This SAR study showed that the antitrypanosomal pharmacophore was less restrictive than the antileishmanial one and highlighted positions 2, 6 and 8 of the imidazopyridine ring as key modulation points. None of the synthesized compounds allowed improvement in antileishmanial activity, compared to previous hit molecules in the series. Nevertheless, compound 8, the best antitrypanosomal molecule in this series (EC50 = 17 nM, SI = 2650 & E° = −0.6 V), was not only more active than all reference drugs and previous hit molecules in the series but also displayed improved aqueous solubility and better in vitro pharmacokinetic characteristics: good microsomal stability (T1/2 > 40 min), moderate albumin binding (77%) and moderate permeability across the blood brain barrier according to a PAMPA assay. Moreover, both micronucleus and comet assays showed that nitroaromatic molecule 8 was not genotoxic in vitro. It was evidenced that bioactivation of molecule 8 was operated by T. b. brucei type 1 nitroreductase, in the same manner as fexinidazole. Finally, a mouse pharmacokinetic study showed that 8 displayed good systemic exposure after both single and repeated oral administrations at 100 mg/kg (NOAEL) and satisfying plasmatic half-life (T1/2 = 7.7 h). Thus, molecule 8 appears as a good candidate for initiating a hit to lead drug discovery program

    The Influence of Number and Timing of Pregnancies on Breast Cancer Risk for Women With BRCA1 or BRCA2 Mutations

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    International audienceBACKGROUND:Full-term pregnancy (FTP) is associated with a reduced breast cancer (BC) risk over time, but women are at increased BC risk in the immediate years following an FTP. No large prospective studies, however, have examined whether the number and timing of pregnancies are associated with BC risk for BRCA1 and BRCA2 mutation carriers.METHODS:Using weighted and time-varying Cox proportional hazards models, we investigated whether reproductive events are associated with BC risk for mutation carriers using a retrospective cohort (5707 BRCA1 and 3525 BRCA2 mutation carriers) and a prospective cohort (2276 BRCA1 and 1610 BRCA2 mutation carriers), separately for each cohort and the combined prospective and retrospective cohort.RESULTS:For BRCA1 mutation carriers, there was no overall association with parity compared with nulliparity (combined hazard ratio [HRc] = 0.99, 95% confidence interval [CI] = 0.83 to 1.18). Relative to being uniparous, an increased number of FTPs was associated with decreased BC risk (HRc = 0.79, 95% CI = 0.69 to 0.91; HRc = 0.70, 95% CI = 0.59 to 0.82; HRc = 0.50, 95% CI = 0.40 to 0.63, for 2, 3, and ≥4 FTPs, respectively, P trend < .0001) and increasing duration of breastfeeding was associated with decreased BC risk (combined cohort P trend = .0003). Relative to being nulliparous, uniparous BRCA1 mutation carriers were at increased BC risk in the prospective analysis (prospective hazard ration [HRp] = 1.69, 95% CI = 1.09 to 2.62). For BRCA2 mutation carriers, being parous was associated with a 30% increase in BC risk (HRc = 1.33, 95% CI = 1.05 to 1.69), and there was no apparent decrease in risk associated with multiparity except for having at least 4 FTPs vs. 1 FTP (HRc = 0.72, 95% CI = 0.54 to 0.98).CONCLUSIONS:These findings suggest differential associations with parity between BRCA1 and BRCA2 mutation carriers with higher risk for uniparous BRCA1 carriers and parous BRCA2 carriers

    Vaccine breakthrough hypoxemic COVID-19 pneumonia in patients with auto-Abs neutralizing type I IFNs

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    Life-threatening `breakthrough' cases of critical COVID-19 are attributed to poor or waning antibody response to the SARS- CoV-2 vaccine in individuals already at risk. Pre-existing autoantibodies (auto-Abs) neutralizing type I IFNs underlie at least 15% of critical COVID-19 pneumonia cases in unvaccinated individuals; however, their contribution to hypoxemic breakthrough cases in vaccinated people remains unknown. Here, we studied a cohort of 48 individuals ( age 20-86 years) who received 2 doses of an mRNA vaccine and developed a breakthrough infection with hypoxemic COVID-19 pneumonia 2 weeks to 4 months later. Antibody levels to the vaccine, neutralization of the virus, and auto- Abs to type I IFNs were measured in the plasma. Forty-two individuals had no known deficiency of B cell immunity and a normal antibody response to the vaccine. Among them, ten (24%) had auto-Abs neutralizing type I IFNs (aged 43-86 years). Eight of these ten patients had auto-Abs neutralizing both IFN-a2 and IFN-., while two neutralized IFN-omega only. No patient neutralized IFN-ss. Seven neutralized 10 ng/mL of type I IFNs, and three 100 pg/mL only. Seven patients neutralized SARS-CoV-2 D614G and the Delta variant (B.1.617.2) efficiently, while one patient neutralized Delta slightly less efficiently. Two of the three patients neutralizing only 100 pg/mL of type I IFNs neutralized both D61G and Delta less efficiently. Despite two mRNA vaccine inoculations and the presence of circulating antibodies capable of neutralizing SARS-CoV-2, auto-Abs neutralizing type I IFNs may underlie a significant proportion of hypoxemic COVID-19 pneumonia cases, highlighting the importance of this particularly vulnerable population

    Correction to: Risk-reducing salpingo-oophorectomy, natural menopause, and breast cancer risk: an international prospective cohort of BRCA1 and BRCA2 mutation carriers.

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    After publication of the original article [1], we were notified that columns in Table 2 were erroneously displayed
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