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1.
J Clin Microbiol ; 62(4): e0142823, 2024 Apr 10.
Artigo em Inglês | MEDLINE | ID: mdl-38470023

RESUMO

The molecular detection of Toxoplasma gondii DNA is a key tool for the diagnosis of disseminated and congenital toxoplasmosis. This multicentric study from the Molecular Biology Pole of the French National Reference Center for toxoplasmosis aimed to evaluate Toxoplasma gondii Real-TM PCR kit (Sacace). The study compared the analytical and clinical performances of this PCR assay with the reference PCRs used in proficient laboratories. PCR efficiencies varied from 90% to 112%; linearity zone extended over four log units (R2 > 0.99) and limit of detection varied from 0.01 to ≤1 Tg/mL depending on the center. Determined on 173 cryopreserved DNAs from a large range of clinical specimens, clinical sensitivity was 100% [106/106; 95 confidence interval (CI): 96.5%-100%] and specificity was 100% (67/67; 95 CI: 94.6%-100%). The study revealed two potential limitations of the Sacace PCR assay: the first was the inconsistency of the internal control (IC) when added to the PCR mixture. This point was not found under routine conditions when the IC was added during the extraction step. The second is a lack of practicality, as the mixture is distributed over several vials, requiring numerous pipetting operations. Overall, this study provides useful information for the molecular diagnosis of toxoplasmosis; the analytical and clinical performances of the Sacace PCR kit were satisfactory, the kit having sensitivity and specificity similar to those of expert center methods and being able to detect low parasite loads, at levels where multiplicative analysis gives inconsistently positive results. Finally, the study recommends multiplicative analysis in particular for amniotic fluids, aqueous humor, and other single specimens.


Assuntos
Toxoplasma , Toxoplasmose Congênita , Toxoplasmose , Humanos , Toxoplasma/genética , Toxoplasmose/diagnóstico , Toxoplasmose/parasitologia , Toxoplasmose Congênita/diagnóstico , Toxoplasmose Congênita/parasitologia , DNA , Kit de Reagentes para Diagnóstico , Sensibilidade e Especificidade , DNA de Protozoário/genética , DNA de Protozoário/análise
2.
Alzheimers Dement ; 20(3): 1839-1850, 2024 03.
Artigo em Inglês | MEDLINE | ID: mdl-38145469

RESUMO

INTRODUCTION: Alzheimer's Prevention Initiative Generation Study 1 evaluated amyloid beta (Aß) active immunotherapy (vaccine) CAD106 and BACE-1 inhibitor umibecestat in cognitively unimpaired 60- to 75-year-old participants at genetic risk for Alzheimer's disease (AD). The study was reduced in size and terminated early. Results from the CAD106 cohort are presented. METHODS: Sixty-five apolipoprotein E ε4 homozygotes with/without amyloid deposition received intramuscular CAD106 450 µg (n = 42) or placebo (n = 23) at baseline; Weeks 1, 7, 13; and quarterly; 51 of them had follow-up Aß positron emission tomography (PET) scans at 18 to 24 months. RESULTS: CAD106 induced measurable serum Aß immunoglobulin G titers in 41/42 participants, slower rates of Aß plaque accumulation (mean [standard deviation] annualized change from baseline in amyloid PET Centiloid: -0.91[5.65] for CAD106 versus 8.36 [6.68] for placebo; P < 0.001), and three amyloid-related imaging abnormality cases (one symptomatic). DISCUSSION: Despite early termination, these findings support the potential value of conducting larger prevention trials of Aß active immunotherapies in individuals at risk for AD. HIGHLIGHTS: This was the first amyloid-lowering prevention trial in persons at genetic risk of late-onset Alzheimer's disease (AD). Active immunotherapy targeting amyloid (CAD106) was tested in this prevention trial. CAD106 significantly slowed down amyloid plaque deposition in apolipoprotein E homozygotes. CAD106 was generally safe and well tolerated, with only three amyloid-related imaging abnormality cases (one symptomatic). Such an approach deserves further evaluation in larger AD prevention trials.


Assuntos
Doença de Alzheimer , Peptídeos beta-Amiloides , Humanos , Pessoa de Meia-Idade , Idoso , Peptídeos beta-Amiloides/metabolismo , Doença de Alzheimer/terapia , Doença de Alzheimer/tratamento farmacológico , Homozigoto , Apolipoproteína E4/genética , Placa Amiloide , Amiloide/metabolismo , Tomografia por Emissão de Pósitrons , Imunoterapia , Encéfalo/metabolismo
3.
J Med Genet ; 59(12): 1234-1240, 2022 12.
Artigo em Inglês | MEDLINE | ID: mdl-36137615

RESUMO

BACKGROUND: Despite the availability of whole exome (WES) and genome sequencing (WGS), chromosomal microarray (CMA) remains the first-line diagnostic test in most rare disorders diagnostic workup, looking for copy number variations (CNVs), with a diagnostic yield of 10%-20%. The question of the equivalence of CMA and WES in CNV calling is an organisational and economic question, especially when ordering a WGS after a negative CMA and/or WES. METHODS: This study measures the equivalence between CMA and GATK4 exome sequencing depth of coverage method in detecting coding CNVs on a retrospective cohort of 615 unrelated individuals. A prospective detection of WES-CNV on a cohort of 2418 unrelated individuals, including the 615 individuals from the validation cohort, was performed. RESULTS: On the retrospective validation cohort, every CNV detectable by the method (ie, a CNV with at least one exon not in a dark zone) was accurately called (64/64 events). In the prospective cohort, 32 diagnoses were performed among the 2418 individuals with CNVs ranging from 704 bp to aneuploidy. An incidental finding was reported. The overall increase in diagnostic yield was of 1.7%, varying from 1.2% in individuals with multiple congenital anomalies to 1.9% in individuals with chronic kidney failure. CONCLUSION: Combining single-nucleotide variant (SNV) and CNV detection increases the suitability of exome sequencing as a first-tier diagnostic test for suspected rare Mendelian disorders. Before considering the prescription of a WGS after a negative WES, a careful reanalysis with updated CNV calling and SNV annotation should be considered.


Assuntos
Variações do Número de Cópias de DNA , Exoma , Humanos , Variações do Número de Cópias de DNA/genética , Exoma/genética , Estudos Retrospectivos , Sequenciamento de Nucleotídeos em Larga Escala/métodos , Estudos Prospectivos
4.
Inorg Chem ; 60(12): 8692-8703, 2021 Jun 21.
Artigo em Inglês | MEDLINE | ID: mdl-34110135

RESUMO

This article reports the syntheses, characterization, structural description, together with magnetic and spectroscopic properties of two isostructural molecular magnets based on the chiral ligand N,N'-bis((1,2-diphenyl-(pyridine-2-yl)methylene)-(R,R/S,S)-ethane-1,2-diamine), L1, of general formula [Ln2(RR-L1)2(Cl6)]·MeOH·1.5H2O, (Ln = Ce (1) or Nd (2)). Multifrequency electron paramagnetic resonance (EPR), cantilever torque magnetometry (CTM) measurements, and ab initio calculations allowed us to determine single-ion magnetic anisotropy and intramolecular magnetic interactions in both compounds, evidencing a more important role of the anisotropic exchange for the NdIII derivative. The comparison of experimental and theoretical data indicates that, in the case of largely rhombic lanthanide ions, ab initio calculations can fail in determining the orientation of the weakest components, while being reliable in determining their principal values. However, they remain of paramount importance to set the analysis of EPR and CTM on sound basis, thus obtaining a very precise picture of the magnetic interactions in these systems. Finally, the electronic structure of the two complexes, as obtained by this approach, is consistent with the absence of zero-field slow relaxation observed in ac susceptibility.

5.
Biologicals ; 71: 9-19, 2021 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-34006447

RESUMO

The European Directorate for the Quality of Medicines & HealthCare (EDQM) has run proficiency testing schemes on the detection of viral contaminants in human plasma pools by nucleic-acid amplification techniques since 1999 for hepatitis C virus and since 2004 for parvovirus B19. A retrospective analysis was performed to assess their impact and identify trends and progress in the results obtained by participating laboratories over a 15-year span, from 2004 to 2018. The results demonstrate that overall performance improved over that time, especially among the regular participants. Participation in these proficiency testing schemes is therefore recommended for all interested control laboratories. This analysis also shows that hepatitis C virus detection now seems well established compared to that of parvovirus B19, which still appears more challenging.


Assuntos
Hepacivirus/isolamento & purificação , Parvovirus B19 Humano/isolamento & purificação , Plasma/virologia , Doadores de Sangue , DNA Viral/isolamento & purificação , Hepacivirus/genética , Humanos , Parvovirus B19 Humano/genética , Estudos Retrospectivos
6.
J Virol ; 93(10)2019 05 15.
Artigo em Inglês | MEDLINE | ID: mdl-30842319

RESUMO

Recent emergence of direct-acting antivirals (DAAs) targeting hepatitis C virus (HCV) proteins has considerably enhanced the success of antiviral therapy. However, the appearance of DAA-resistant-associated variants is a cause of treatment failure, and the high cost of DAAs renders the therapy not accessible in countries with inadequate medical infrastructures. Therefore, the search for new inhibitors with a lower cost of production should be pursued. In this context, the crude extract of Juncus maritimus Lam. was shown to exhibit high antiviral activity against HCV in cell culture. Bio-guided fractionation allowed the isolation and identification of the active compound, dehydrojuncusol. A time-of-addition assay showed that dehydrojuncusol significantly inhibited HCV infection when added after virus inoculation of HCV genotype 2a (50% effective concentration [EC50] = 1.35 µM). This antiviral activity was confirmed with an HCV subgenomic replicon, and no effect on HCV pseudoparticle entry was observed. Antiviral activity of dehydrojuncusol was also demonstrated in primary human hepatocytes. No in vitro toxicity was observed at active concentrations. Dehydrojuncusol is also efficient on HCV genotype 3a and can be used in combination with sofosbuvir. Interestingly, dehydrojuncusol was able to inhibit RNA replication of two frequent daclatasvir-resistant mutants (L31M or Y93H in NS5A). Finally, mutants resistant to dehydrojuncusol were obtained and showed that the HCV NS5A protein is the target of the molecule. In conclusion, dehydrojuncusol, a natural compound extracted from J. maritimus, inhibits infection of different HCV genotypes by targeting the NS5A protein and is active against resistant HCV variants frequently found in patients with treatment failure.IMPORTANCE Tens of millions of people are infected with hepatitis C virus (HCV) worldwide. Recently marketed direct-acting antivirals (DAAs) targeting HCV proteins have enhanced the efficacy of treatment. However, due to its high cost, this new therapy is not accessible to the vast majority of infected patients. Furthermore, treatment failures have also been reported due to the appearance of viral resistance. Here, we report on the identification of a new HCV inhibitor, dehydrojuncusol, that targets HCV NS5A and is able to inhibit RNA replication of replicons harboring resistance mutations to anti-NS5A DAAs used in current therapy. Dehydrojuncusol is a natural compound isolated from Juncus maritimus, a halophilic plant species that is very common in coastlines worldwide. This molecule might serve as a lead for the development of a new therapy that is more accessible to hepatitis C patients in the future.


Assuntos
Hepacivirus/efeitos dos fármacos , Fenantrenos/farmacologia , Replicação Viral/efeitos dos fármacos , Antivirais/farmacologia , Linhagem Celular , Farmacorresistência Viral/genética , Genótipo , Células HEK293 , Hepacivirus/genética , Hepatite C/genética , Hepatite C/virologia , Hepatite C Crônica/virologia , Hepatócitos/virologia , Humanos , Fenantrenos/metabolismo , Fenetilaminas/farmacologia , Extratos Vegetais/farmacologia , Inibidores de Proteases/farmacologia , Replicon/efeitos dos fármacos , Rizoma
7.
Malar J ; 19(1): 179, 2020 May 11.
Artigo em Inglês | MEDLINE | ID: mdl-32393251

RESUMO

BACKGROUND: Rapid diagnostic tests (RDTs) detecting the histidine-rich protein 2 (PfHRP2) have a central position for the management of Plasmodium falciparum infections. Yet, variable detection of certain targeted motifs, low parasitaemia, but also deletion of pfhrp2 gene or its homologue pfhrp3, may result in false-negative RDT leading to misdiagnosis and delayed treatment. This study aimed at investigating the prevalence, and understanding the possible causes, of P. falciparum RDT-negative infections at Montpellier Academic Hospital, France. METHODS: The prevalence of falsely-negative RDT results reported before and after the introduction of a loop-mediated isothermal amplification (LAMP) assay, as part as the malaria screening strategy in January 2017, was analysed. Negative P. falciparum RDT infections were screened for pfhrp2 or pfhrp3 deletion; and exons 2 were sequenced to show a putative genetic diversity impairing PfHRP2 detection. RESULTS: The overall prevalence of P. falciparum negative RDTs from January 2006 to December 2018 was low (3/446). Whereas no cases were reported from 2006 to 2016 (0/373), period during which the malaria diagnostic screen was based on microscopy and RDT, prevalence increased up to 4.1% (3/73) between 2017 and 2018, when molecular detection was implemented for primary screening. Neither pfhrp2/3 deletion nor major variation in the frequency of repetitive epitopes could explain these false-negative RDT results. CONCLUSION: This paper demonstrates the presence of pfhrp2 and pfhrp3 genes in three P. falciparum RDT-negative infections and reviews the possible reasons for non-detection of HRP2/3 antigens in a non-endemic setting. It highlights the emergence of falsely negative rapid diagnostic tests in a non-endemic setting and draws attention on the risk of missing malaria cases with low parasitaemia infections using the RDT plus microscopy-based strategy currently recommended by French authorities. The relevance of a novel diagnostic scheme based upon a LAMP assay is discussed.


Assuntos
Antígenos de Protozoários/análise , Testes Diagnósticos de Rotina/estatística & dados numéricos , Plasmodium falciparum/isolamento & purificação , Proteínas de Protozoários/análise , Reações Falso-Negativas , França/epidemiologia , Malária Falciparum/epidemiologia , Plasmodium falciparum/genética , Prevalência
8.
Eur Radiol ; 30(7): 3960-3967, 2020 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-32100088

RESUMO

OBJECTIVES: In the ascending aorta, calcification density was independently and inversely associated with cardiovascular disease (CVD) risk prediction. Until now, the density of thoracic aorta calcium (TAC) was estimated as the Agatston score divided by the calcium area (DAG). We thought to analyze TAC density in a full Hounsfield unit (HU) range and to study its association with TAC volume, traditional risk factors, and CVD events. METHODS: Non-enhanced CT images of 1426 patients at intermediate risk were retrospectively reviewed. A calcium density score was estimated as the average of the maximum HU attenuation in all calcified plaques of the entire thoracic aorta (DAV). RESULTS: During a mean 4.0 years follow-up, there were 26 events for a total of 674 patients with TAC > 0. TAC volume and DAV were positively correlated (R = 0.72). The median DAV value was 457 HU (IQ 323-603 HU) and was exponentially related to DAG (R = 0.86). DAV was inversely associated with systolic pressure (p < 0.05), pulse pressure (p < 0.01), hypertension (p < 0.05), and 10-year FRS (p < 0.001) after adjusting for TAC volume. When TAC volume and DAV were included in a logistic model, a significant improvement was shown in CVD risk estimation beyond coronary artery calcium (CAC) (AUC = 0.768 vs 0.814, p < 0.05). In multivariable Cox models, TAC volume and DAV showed an independent association with CVD. CONCLUSIONS: In intermediate risk patients, TAC density was inversely associated with several risk factors after adjustment for TAC volume. A significant improvement was observed over CAC when TAC volume and density were added into the risk prediction model. KEY POINTS: • Calcifications in the aorta can be non-invasively assessed using CT images • A higher calcium score is associated with a higher cardiovascular risk • Measuring the calcifications size and the density separately can improve the risk prediction.


Assuntos
Angiografia/métodos , Aorta Torácica/diagnóstico por imagem , Doenças da Aorta/diagnóstico , Calcinose/diagnóstico , Cálcio/metabolismo , Aorta Torácica/metabolismo , Doenças da Aorta/metabolismo , Feminino , Humanos , Masculino , Pessoa de Meia-Idade , Modelos de Riscos Proporcionais , Estudos Retrospectivos , Medição de Risco , Fatores de Risco
9.
Inorg Chem ; 59(10): 7067-7081, 2020 May 18.
Artigo em Inglês | MEDLINE | ID: mdl-32378897

RESUMO

The three Co(II) complexes [Co(bbp)2][Co(NCS)4]·4DMF (1), [Co(bbp)(NCS)2(DMF)]·2DMF (2), and [Co(bbp)(NCS)2] (3) have been synthesized and characterized by single-crystal X-ray diffraction, magnetic, and various spectroscopic techniques. Complexes 1 and 3 are obtained by the reaction of Co(NCS)2 with 2,6-bis(1H-benzo[d]imidazol-2-yl)pyridine (bbp), and complex 1 undergoes a structural transformation to form complex 2. A single-crystal X-ray study revealed that complex 1 is comprised of two Co(II) centers, a cationic octahedral Co(II) unit and an anionic tetrahedral Co(II) unit, while the Co(II) ion is in a distorted-octahedral environment in 2. Moreover, in complex 3, the Co(II) ion is in a distorted-square-pyramidal geometry. The effect of coordination geometry on the magnetic properties was studied by both static and dynamic magnetic measurements. Direct current (dc) magnetic susceptibility measurements showed that all of the Co(II) ions are in high-spin state in these complexes. Alternating current (ac) magnetic susceptibility measurements indicated that complexes 2 and 3 display slow relaxation of magnetization in an external dc magnetic field, while complex 1 displayed no such property. EPR experiments and theoretical calculations were consistent with the above findings.

10.
Mult Scler ; 25(12): 1661-1672, 2019 10.
Artigo em Inglês | MEDLINE | ID: mdl-30160208

RESUMO

BACKGROUND: Diagnosis of multiple sclerosis (MS) during childhood has the potential to impact the affected child's self-perception and the health-related quality of life (HRQoL) of the family. OBJECTIVE: To evaluate the impact of chronic disease, in children ascertained as having MS and their families, when compared to those with monophasic acquired demyelinating syndrome (monoADS). METHODS: In a national prospective cohort study of pediatric acquired demyelinating syndromes (ADS), the HRQoL of children and their families was captured using the Pediatric Quality of Life Inventory (PedsQL™) Modules. RESULTS: Participants (58 MS; 178 monoADS) provided cross-sectional HRQoL data a median (interquartile range (IQR)) of 4.1 (2.0-6.0) years after disease onset. The HRQoL of parents of children with MS and their family functioning was lower when compared to that of parents and families of children with monoADS (both p < 0.001); parents of children with MS reported greater emotional dysfunction, worry, worse communication, and lower family functioning irrespective of clinical disease activity. Self-reports of the MS and monoADS participants did not suggest a difference in overall HRQoL or fatigue after adjusting for age of the child at the time of assessment. CONCLUSION: While children with MS did not self-report lower HRQoL compared to children who experienced monoADS, the diagnosis of MS during childhood was negatively associated with parental HRQoL and family functioning.


Assuntos
Esclerose Múltipla/fisiopatologia , Esclerose Múltipla/psicologia , Pais/psicologia , Qualidade de Vida/psicologia , Adolescente , Criança , Pré-Escolar , Estudos Transversais , Feminino , Humanos , Masculino , Estudos Prospectivos , Autorrelato , Inquéritos e Questionários
11.
Inorg Chem ; 58(7): 4230-4243, 2019 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-30892028

RESUMO

The family of complexes of general formula [Co(Me ntpa)(Xdiox)]+ (tpa = tris(2-pyridylmethyl)amine, n = 0-3 corresponds to successive methylation of the 6-position of the pyridine rings; X = Br4, Cl4, H4, 3,5-Me2, 3,5- tBu2; diox = dioxolene) was investigated by density functional theory (DFT) calculations to predict the likelihood of valence tautomerism (VT). The OPBE functional with relativistic and solvent corrections allowed accurate reproduction of trends in spin-state energetics, affording the prediction of VT in complex [Co(Me3tpa)(Br4diox)]+ (1+). One-electron oxidation of neutral precursor [CoII(Me3tpa)(Br4cat)] (1) enabled isolation of target compounds 1(PF6) and 1(BPh4). Solution variable-temperature UV-vis absorption and Evans method magnetic susceptibility data confirm DFT predictions that 1+ exists in a temperature-dependent valence tautomeric equilibrium between low-spin Co(III)-catecholate and high-spin Co(II)-semiquinonate forms. The solution VT transition temperature of 1+ is solvent-tunable with critical temperatures in the range of 291-359 K for the solvents measured. Solid-state magnetic susceptibility measurements of 1(PF6) and 1(BPh4) reveal the onset of VT transitions above room temperature.

12.
Sante Publique ; Vol. 31(1): 83-92, 2019.
Artigo em Francês | MEDLINE | ID: mdl-31210521

RESUMO

OBJECTIVE: The goal of this review is to present online social support interventions described in recent scientific literature, in order to (i) guide organizations wishing to develop such an intervention or to improve an existing program, and (ii) to identify future research directions and recommendations for practitioners. METHODS AND RESULTS: 59 peer-reviewed articles presenting online social support interventions (2006-2016) were analyzed by using a thematic grid focusing on theoretical perspectives on social support, the online platforms used and their functionalities, the process of intervention development and evaluation, the modalities of participation and the facilitation methods, the documented impacts of interventions, and finally future research directions and recommendations for practitioners. A narrative methodology was used to identify challenges in intervention development and implementation, in order to provide guidance to organizations who want to develop or improve their online social support services. CONCLUSIONS: Several research directions and recommendations for the development of online social support interventions are suggested, including the need to develop theoretical models of online social support and enrich traditional models of social support, the need to understand the benefits associated with different levels of participation, the importance of needs assessment in the development of interventions, and the contribution of qualitative methods to the evaluation of interventions.


Assuntos
Promoção da Saúde/métodos , Internet , Rede Social , Apoio Social , Humanos , Motivação , Pesquisa/tendências , Grupos de Autoajuda
13.
J Am Chem Soc ; 140(38): 12090-12101, 2018 09 26.
Artigo em Inglês | MEDLINE | ID: mdl-30145887

RESUMO

Practical implementation of highly coherent molecular spin qubits for challenging technological applications, such as quantum information processing or quantum sensing, requires precise organization of electronic qubit molecular components into extended frameworks. Realization of spatial control over qubit-qubit distances can be achieved by coordination chemistry approaches through an appropriate choice of the molecular building blocks. However, translating single qubit molecular building units into extended arrays does not guarantee a priori retention of long quantum coherence and spin-lattice relaxation times due to the introduced modifications over qubit-qubit reciprocal distances and molecular crystal lattice phonon structure. In this work, we report the preparation of a three-dimensional (3D) metal-organic framework (MOF) based on vanadyl qubits, [VO(TCPP-Zn2-bpy)] (TCPP = tetracarboxylphenylporphyrinate; bpy = 4,4'-bipyridyl) (1), and the investigation of how such structural modifications influence qubits' performances. This has been done through a multitechnique approach where the structure and properties of a representative molecular building block of formula [VO(TPP)] (TPP = tetraphenylporphyrinate) (2) have been compared with those of the 3D MOF 1. Pulsed electron paramagnetic resonance measurements on magnetically diluted samples in titanyl isostructural analogues revealed that coherence times are retained almost unchanged for 1 with respect to 2 up to room temperature, while the temperature dependence of the spin-lattice relaxation time revealed insights into the role of low-energy vibrations, detected through terahertz spectroscopy, on the spin dynamics.

14.
J Synchrotron Radiat ; 25(Pt 1): 59-67, 2018 Jan 01.
Artigo em Inglês | MEDLINE | ID: mdl-29271752

RESUMO

It is now well established that laser plasma acceleration (LPA) is an innovative and good candidate in the beam acceleration field. Relativistic beams are indeed produced up to several GeV but their quality remains to be demonstrated in the highly demanding case of free-electron lasers (FELs). Several experiments have already shown the feasibility of synchrotron radiation delivery based on LPA but free-electron lasing has still to be achieved. Since the quality of the LPA beam inside the undulator is the critical issue, any LPA-based FEL experiment requires a refined characterization of the beam properties along the transport line and of the photon beam at the undulator exit. This characterization relies on diagnostics which must be adapted to the LPA specificities. Here, the electron and photon diagnostics already used on LPAs and required for LPA-based FELs are reviewed, and the critical points are illustrated using recent experiments performed around the world.

15.
J Synchrotron Radiat ; 25(Pt 2): 385-398, 2018 Mar 01.
Artigo em Inglês | MEDLINE | ID: mdl-29488917

RESUMO

The investigation of ultrafast dynamics, taking place on the few to sub-picosecond time scale, is today a very active research area pursued in a variety of scientific domains. With the recent advent of X-ray free-electron lasers (XFELs), providing very intense X-ray pulses of duration as short as a few femtoseconds, this research field has gained further momentum. As a consequence, the demand for access strongly exceeds the capacity of the very few XFEL facilities existing worldwide. This situation motivates the development of alternative sub-picosecond pulsed X-ray sources among which femtoslicing facilities at synchrotron radiation storage rings are standing out due to their tunability over an extended photon energy range and their high stability. Following the success of the femtoslicing installations at ALS, BESSY-II, SLS and UVSOR, SOLEIL decided to implement a femtoslicing facility. Several challenges were faced, including operation at the highest electron beam energy ever, and achievement of slice separation exclusively with the natural dispersion function of the storage ring. SOLEIL's setup also enables, for the first time, delivering sub-picosecond pulses simultaneously to several beamlines. This last feature enlarges the experimental capabilities of the facility, which covers the soft and hard X-ray photon energy range. In this paper, the commissioning of this original femtoslicing facility is reported. Furthermore, it is shown that the slicing-induced THz signal can be used to derive a quantitative estimate for the degree of energy exchange between the femtosecond infrared laser pulse and the circulating electron bunch.

16.
Chemistry ; 24(55): 14768-14785, 2018 Oct 01.
Artigo em Inglês | MEDLINE | ID: mdl-29992641

RESUMO

The combination of lanthanoid nitrates with 18-crown-6 (18-c-6) and tetrahalocatecholate (X4 Cat2- , X=Cl, Br) ligands has afforded two compound series [Ln(18-c-6)(X4 Cat)(NO3 )]⋅MeCN (X=Cl, 1-Ln; X=Br, 2-Ln; Ln=La, Ce, Nd, Gd, Tb, Dy). The 18-c-6 ligands occupy equatorial positions of a distorted sphenocorona geometry, whereas the charged ligands occupy the axial positions. The analogues of both series with Ln=Ce, Nd, Tb and Dy exhibit out-of-phase ac magnetic susceptibility signals in the presence of an applied magnetic field, indicative of slow magnetization relaxation. When diluted into a diamagnetic La host to reduce dipolar interactions, the Dy analogue exhibits slow relaxation up to 20 K in the absence of an applied dc field. Concerted magnetic measurements, EPR spectroscopy, and ab initio calculations have allowed elucidation of the mechanisms responsible for slow magnetic relaxation. A consistent approach has been applied to quantitatively model the relaxation data for different lanthanoid analogues, suggesting that the spin dynamics are governed by Raman processes at higher temperatures, transitioning to a dominant phonon bottleneck process as the temperature is decreased, with an observed T-6 rather than the usual T-2 dependence (T is temperature). This anomalous thermal dependence of the phonon bottleneck relaxation is consistent with anharmonic effects in the lattice dynamics, which was predicted by Van Vleck more than 70 years ago.

17.
Biologicals ; 52: 78-82, 2018 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-29395838

RESUMO

Within the Innovative Medicines Initiative 2 (IMI 2) project VAC2VAC (Vaccine batch to vaccine batch comparison by consistency testing), a workshop has been organised to discuss ways of improving the design of multi-centre validation studies and use the data generated for product-specific validation purposes. Moreover, aspects of validation within the consistency approach context were addressed. This report summarises the discussions and outlines the conclusions and recommendations agreed on by the workshop participants.


Assuntos
Conferências de Consenso como Assunto , Estudos Multicêntricos como Assunto , Guias de Prática Clínica como Assunto , Vacinas/uso terapêutico , Estudos de Validação como Assunto , Humanos
18.
J Clin Microbiol ; 55(5): 1369-1376, 2017 05.
Artigo em Inglês | MEDLINE | ID: mdl-28202794

RESUMO

Molecular diagnosis of congenital toxoplasmosis or disseminated toxoplasmosis is based mainly on PCR. The repeated DNA element rep529 has become the main DNA target used in most PCR methods, whether laboratory developed or commercial. In this multicenter study, we evaluated the Toxoplasma ELITe MGB (Elitech) commercial kit by comparison with three reference quantitative PCR assays (RAs) used routinely in three proficient laboratories of the French National Reference Center for Toxoplasmosis network, using Toxoplasma calibrated suspensions diluted to obtain a range of concentrations from 0.1 to 10,000 parasites/ml. These suspensions were extracted with either the DNA extraction kit (EXTRAblood; Elitech) recommended by the manufacturer or the QIAamp DNA minikit (Qiagen). The Toxoplasma ELITe MGB assay was also evaluated on a panel of 128 clinical samples, including 56 amniotic fluid samples, 55 placenta samples, and various other samples, of which 95 originated from patients with proven toxoplasmosis. The ELITe MGB assay amplified low-concentration replicates (<10 parasites/ml) of calibrated suspensions less frequently than the RAs of 2/3 laboratories. Additionally, the combination of EXTRAblood and Toxoplasma ELITe MGB yielded poorer sensitivity than the combination of QIAamp DNA minikit and ELITe MGB for low parasite concentrations (P < 0.001 for 1 parasite/ml). On clinical samples, the sensitivity and the specificity of the commercial assay were 89% and 100%, respectively. The sensitivity ranged from 79% (placenta samples) to 100% (amniotic fluid samples). Overall, this study shows that the Toxoplasma ELITe MGB assay is suitable for the diagnosis of toxoplasmosis from non-cell-rich or non-hemoglobin-rich samples and that the EXTRAblood kit is not optimal.


Assuntos
DNA de Protozoário/genética , Técnicas de Diagnóstico Molecular/métodos , Reação em Cadeia da Polimerase em Tempo Real/métodos , Toxoplasma/genética , Toxoplasmose Congênita/diagnóstico , Líquido Amniótico/parasitologia , Feminino , Humanos , Placenta/parasitologia , Gravidez , Sensibilidade e Especificidade , Toxoplasma/isolamento & purificação , Toxoplasmose Congênita/parasitologia
19.
Am J Pathol ; 186(5): 1313-27, 2016 05.
Artigo em Inglês | MEDLINE | ID: mdl-26952641

RESUMO

Skeletal muscle damage is an often-occurring event. Diagnosis using the classic blood marker creatine kinase sometimes yields unsatisfactory results due to great interindividual variability. Therefore, the identification of reliable biomarkers is important. Our aim was to detect and characterize circulating miRNAs in plasma in response to acute notexin-induced muscle damage in rats. Real-time quantitative RT-PCR profiling led to the identification of miRNAs that were highly increased in plasma in response to notexin injection into several muscles, namely miR-1-3p, -133a-3p, -133b-3p, -206-3p, -208b-3p, and -499-5p, as well as miR-378a-3p and miR-434-3p. Peak values of miRNAs appeared 12 hours after injury, and were contained both in the vesicular and nonvesicular fractions of plasma. Receiver operating characteristic curve analysis showed that circulating miRNAs could accurately discriminate between damaged and nondamaged tissues. Furthermore, we tested the robustness of expression profiles in slow- and fast-type fibers. Upon inducing damage in slow- or fast-type muscle, we found that the damaged-muscle phenotype had a very limited impact on the miRNA response. Similarly, the circulating miRNAs selected were not affected by hemolysis or platelets, two pre-analytical factors known to affect plasma miRNA profiles. Taken together, our results show that circulating muscle-specific miRNAs, miR-378a-3p and miR-434-3p, are robust and promising biomarkers of acute muscle damage in rats.


Assuntos
MicroRNAs/metabolismo , Doenças Musculares/diagnóstico , Animais , Biomarcadores/metabolismo , Venenos Elapídicos/toxicidade , Feminino , Masculino , Músculo Esquelético/efeitos dos fármacos , Doenças Musculares/induzido quimicamente , Neurotoxinas/toxicidade , Ratos Wistar
20.
Inorg Chem ; 56(5): 2496-2505, 2017 Mar 06.
Artigo em Inglês | MEDLINE | ID: mdl-28207243

RESUMO

A series of lanthanide complexes bearing organic radical ligands, [Ln(CpR)2(bipy·-)] [Ln = La, CpR = Cptt (1); Ln = Ce, CpR = Cptt (2); Ln = Ce, CpR = Cp″ (3); Ln = Ce, CpR = Cp‴ (4)] [Cptt = {C5H3tBu2-1,3}-; Cp″ = {C5H3(SiMe3)2-1,3}-; Cp‴ = {C5H2(SiMe3)3-1,2,4}-; bipy = 2,2'-bipyridyl], were prepared by reduction of [Ln(CpR)2(µ-I)]2 or [Ce(Cp‴)2(I) (THF)] with KC8 in the presence of bipy (THF = tetrahydrofuran). Complexes 1-4 were thoroughly characterized by structural, spectroscopic, and computational methods, together with magnetism and cyclic voltammetry, to define an unambiguous Ln(III)/bipy·- radical formulation. These complexes can act as selective reducing agents; for example, the reaction of 3 with benzophenone gives [{Ce(Cp")2(bipy)}2{κ2-O,O'-OPhC(C6H5)CPh2O}] (7), a rare example of a "head-to-tail" coupling product. We estimate the intramolecular exchange coupling for 2-4 using multiconfigurational and spin Hamiltonian methods and find that the commonly used Lines-type isotropic exchange is not appropriate, even for single 4f e-/organic radical pairs.

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