Your browser doesn't support javascript.
loading
Mostrar: 20 | 50 | 100
Resultados 1 - 18 de 18
Filtrar
Mais filtros










Base de dados
Intervalo de ano de publicação
1.
J Clin Med ; 11(19)2022 Sep 30.
Artigo em Inglês | MEDLINE | ID: mdl-36233667

RESUMO

Hemophagocytic lymphohistiocytosis (HLH) is a life-threatening cytokine storm syndrome. There are no definitive guidelines for the management of secondary HLH (sHLH). A recent report by a National Health Service (NHS) clinical panel has recommended anakinra as a treatment option. We aimed to analyse the efficacy and safety of anakinra for the treatment of all-cause sHLH. We conducted a multicentric retrospective study in two French University hospitals and included all patients who had a diagnosis of sHLH and who received anakinra. Among 21 patients (median age, 45 years), 13 were men. Anakinra was used as first-line therapy in 10 patients, and as monotherapy in 5 patients. We found that anakinra was effective in 19/21 patients (90.5%), with fever resolution in 19 patients (90.5%) within a median of 1.0 day (1, 2). At the Day 7 assessment, the mean CRP concentration decreased significantly (p < 0.001), as did the mean ferritin (p = 0.011). Anakinra was generally safe and well tolerated and was discontinued for side effects in only three patients (14.3%). Anakinra is an efficient and safe treatment to control sHLH of various causes. These data, together with the recent report of the NHS panel, call for the rapid conduct of prospective randomized clinical trials.

3.
Diagnostics (Basel) ; 11(7)2021 Jul 12.
Artigo em Inglês | MEDLINE | ID: mdl-34359324

RESUMO

Sarcoidosis is a systemic granulomatous disease of unknown cause characterized by a wide variety of presentations. Its diagnosis is based on three major criteria: a clinical presentation compatible with sarcoidosis, the presence of non-necrotizing granulomatous inflammation in one or more tissue samples, and the exclusion of alternative causes of granulomatous disease. Many conditions may mimic a sarcoid-like granulomatous reaction. These conditions include infections, neoplasms, immunodeficiencies, and drug-induced diseases. Moreover, patients with sarcoidosis are at risk of developing opportunistic infections or lymphoma. Reliably confirming the diagnosis of sarcoidosis and better identifying new events are major clinical problems in daily practice. To address such issues, we present seven emblematic cases, seen in our department, over a ten-year period along with a literature review about case reports of conditions misdiagnosed as sarcoidosis.

5.
Anal Chem ; 92(11): 7666-7673, 2020 06 02.
Artigo em Inglês | MEDLINE | ID: mdl-32378878

RESUMO

We report an experimental approach for high-resolution real-time monitoring of transiently formed species occurring during the onset of precipitation of ionic solids from solution. This is made possible by real-time nuclear magnetic resonance (NMR) monitoring using dissolution dynamic nuclear polarization (D-DNP) to amplify signals of functional intermediates and is supported by turbidimetry, cryogenic electron microscopy, and solid-state NMR measurements. D-DNP can provide drastic signal improvements in NMR signal amplitudes, permitting dramatic reductions in acquisition times and thereby enabling us to probe fast interaction kinetics such as those underlying formation of prenucleation species (PNS) that precede solid-liquid phase separation. This experimental strategy allows for investigation of the formation of calcium phosphate (CaP)-based minerals by 31P NMR-a process of substantial industrial, geological, and biological interest. Thus far, many aspects of the mechanisms of CaP nucleation remain unclear due to the absence of experimental methods capable of accessing such processes on sufficiently short time scales. The approach reported here aims to address this by an improved characterization of the initial steps of CaP precipitation, permitting detection of PNS by NMR and determination of their formation rates, exchange dynamics, and sizes. Using D-DNP monitoring, we find that under our conditions (i) in the first 2 s after preparation of oversaturated calcium phosphate solutions, PNS with a hydrodynamic radius of Rh ≈ 1 nm is formed and (ii) following this rapid initial formation, the entire crystallization processes proceed on considerably longer time scales, requiring >20 s to form the final crystal phase.


Assuntos
Fosfatos de Cálcio/análise , Espectroscopia de Ressonância Magnética , Fatores de Tempo
6.
Ann Biol Clin (Paris) ; 78(2): 195-197, 2020 Apr 01.
Artigo em Inglês | MEDLINE | ID: mdl-32162605

RESUMO

POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) is a rare paraneoplastic disorder due to an underlying plasma cell dyscrasia. The diagnosis of POEMS syndrome requires a chronic polyneuropathy and a monoclonal lambda plasma cell-proliferative disorder (mandatory criteria), and various systematic symptoms such as sclerotic bone lesions, Castleman's disease, organomegaly, endocrinopathy, skin changes, papilloedema and biological abnormalities such as elevated vascular endothelial growth factor (VEGF), thrombocytosis or polycythaemia. We describe an observation of a patient with recurrent thrombosis with thrombocytosis that, after excluding a myeloproliferative neoplasm, proved to be due to POEMS syndrome. This case is unusual compared to the foreground thrombotic symptomatology. POEMS syndrome (polyneuropathy, organomegaly, endocrinopathy, monoclonal protein, skin changes) is a rare multi-systematic paraneoplastic disorder due to an underlying plasma cell disorder. The diagnosis of POEMS syndrome requires the presence of both mandatory criteria (a chronic polyneuropathy and a monoclonal plasma cell-proliferative disorder, always lambda restricted); at least one major (among sclerotic bone lesions, Castleman's disease, elevated VEGF (vascular endothelial growth factor)) and one minor criterion (among organomegaly, endocrinopathy, skin changes (haemangiomas, hypertrichosis, hyperpigmentation), papilloedema and thrombocytosis or polycythaemia. We describe an unusual observation of a young patient with recurrent thrombosis with thrombocytosis that, after excluding a myeloproliferative neoplasm, proved to be due to POEMS syndrome.


Assuntos
Síndrome POEMS/diagnóstico , Trombose/diagnóstico , Doenças das Glândulas Suprarrenais/diagnóstico , Doenças das Glândulas Suprarrenais/etiologia , Glândulas Suprarrenais/irrigação sanguínea , Adulto , Diagnóstico Diferencial , Humanos , Infarto/diagnóstico , Infarto/etiologia , Masculino , Síndrome POEMS/complicações , Trombose/etiologia
7.
Phys Chem Chem Phys ; 21(38): 21278-21286, 2019 Oct 02.
Artigo em Inglês | MEDLINE | ID: mdl-31549135

RESUMO

We present observations of an NMR MASER (microwave amplification by stimulated emission of radiation) of hyperpolarized 1H nuclei by dynamic nuclear polarization (DNP) at 1.2 K and in a magnetic field of 6.7 T. The sustained maser pulses originate from the interplay between radiation damping (RD) due to the large 1H magnetization, and the remagnetization to a negative value by the DNP process. NMR signals lasting for several tens of seconds are thus observed on an ensemble of dipolar-coupled nuclear spins. Magnetization dynamics are analyzed in terms of the combined Bloch-Maxwell and Provotorov (BMP) equations for RD and DNP. Insight into the long time evolution of the magnetization is provided by a theoretical analysis of this nonlinear dynamical system, and by fitting the NMR signal to a simplified version of the BMP equations.

8.
Angew Chem Int Ed Engl ; 57(18): 5171-5175, 2018 04 23.
Artigo em Inglês | MEDLINE | ID: mdl-29431894

RESUMO

Mixtures of water and glycerol provide popular matrices for low-temperature spectroscopy of vitrified samples. However, they involve counterintuitive physicochemical properties, such as spontaneous nanoscopic phase separations (NPS) in solutions that appear macroscopically homogeneous. We demonstrate that such phenomena can substantially influence the efficiency of dynamic nuclear polarization (DNP) by factors up to 20 % by causing fluctuations in local concentrations of polarization agents (radicals). Thus, a spontaneous NPS of water/glycerol mixtures that takes place on time scales on the order of 30-60 min results in a confinement of polarization agents in nanoscopic water-rich vesicles, which in return affects the DNP. Such effects were found for three common polarization agents, TEMPOL, AMUPol and Trityl.

9.
Chemistry ; 24(21): 5456-5461, 2018 Apr 11.
Artigo em Inglês | MEDLINE | ID: mdl-29356139

RESUMO

The isomerisation of 6-phosphogluconolactones and their hydrolyses into 6-phosphogluconic acid form a non enzymatic side cycle of the pentose-phosphate pathway (PPP) in cells. Dissolution dynamic nuclear polarisation can be used for determining the kinetic rates of the involved transformations in real time. It is found that the hydrolysis of both lactones is significantly slower than the isomerisation process, thereby shedding new light onto this subtle chemical process.


Assuntos
Gluconatos/química , Espectroscopia de Ressonância Magnética/métodos , Cinética , Redes e Vias Metabólicas , Via de Pentose Fosfato/fisiologia , Solubilidade
10.
Medicine (Baltimore) ; 96(37): e7534, 2017 Sep.
Artigo em Inglês | MEDLINE | ID: mdl-28906353

RESUMO

BACKGROUND: Corticosteroid sparing is required in 15% to 40% of adults with persistent or chronic primary immune thrombocytopenic purpura (ITP). Herein, the efficacy of immunomodulatory drugs (dapsone, interferon alpha, danazol, and hydroxychloroquine as second-third-line therapies in ITP is investigated. METHODS: MEDLINE was searched for studies that included patients with persistent or chronic primary ITP and published before the end of December 2014. Two investigators independently extracted data regarding study design, patient characteristics, dosage schedule, time to response, and occurrence of adverse events. The pooled overall response rate (ORR; platelet count >30 × 10 L) and the complete response rate (CRR; platelet count >100 × 10 L) were evaluated to determine drug efficacy by calculating weighted mean proportion using a fixed or random-effects model according to heterogeneity (I > 50%). The study was performed following the MOOSE and PRISMA guidelines. RESULTS: A total of 28 studies (415 patients) were included (dapsone: k = 7 studies, n = 80; danazol: k = 12, n = 224; interferon alpha: k = 8, n = 83; hydroxychloroquine: k = 1, n = 28). The mean patient age was 50 years (female sex 70%, splenectomy 47%). The ORR and CRR were 55% (95% CI: 44%-66%, I = 0%) and 21% (95% CI: 13%-31%, I = 0%), respectively, for dapsone; 42% (95% CI: 22%-65%, I = 63%) and 18% (95% CI: 10%-29%, I = 9%), respectively, for interferon alpha; and 58% (95% CI: 42%-72%, I = 67%) and 29% (95% CI: 19%-42%, I = 63%), respectively, for danazol. The ORR was 50% (95% CI: 32%-67%) for hydroxychloroquine (data not available for CRR). Meta-regression analysis found a correlation between the ORR for interferon alpha and the splenectomized status of the patient (P = .02) and between the CRR for danazol and disease duration (P < .001). In total, 73%, 51%, 30%, and 0% of patients who received danazol, dapsone, interferon alpha, and hydroxychloroquine experienced side effects, respectively. CONCLUSION: The ORR was equivalent for hydroxychloroquine, danazol, and dapsone in ITP. Regarding their low CRR, patients at high risk of infection or at low risk of bleeding should benefit from these treatments. Thanks to their best efficacy and safety profiles, dapsone and hydroxychloroquine in patients with antinuclear antibodies should be preferred over danazol and interferon alpha.


Assuntos
Imunomodulação , Púrpura Trombocitopênica Idiopática/terapia , Humanos
11.
J Chem Phys ; 146(4): 041101, 2017 01 28.
Artigo em Inglês | MEDLINE | ID: mdl-28147551

RESUMO

We report the generation and observation of long-lived spin states in deuterated methyl groups by dissolution DNP. These states are based on population imbalances between manifolds of spin states corresponding to irreducible representations of the C3v point group and feature strongly dampened quadrupolar relaxation. Their lifetime depends on the activation energies of methyl group rotation. With dissolution DNP, we can reduce the deuterium relaxation rate by a factor up to 20, thereby extending the experimentally available time window. The intrinsic limitation of NMR spectroscopy of quadrupolar spins by short relaxation times can thus be alleviated.

12.
Angew Chem Int Ed Engl ; 56(1): 389-392, 2017 01 02.
Artigo em Inglês | MEDLINE | ID: mdl-27918140

RESUMO

Hyperpolarized water can selectively enhance NMR signals of rapidly exchanging protons in osteopontin (OPN), a metastasis-associated intrinsically disordered protein (IDP), at near-physiological pH and temperature. The transfer of magnetization from hyperpolarized water is limited to solvent-exposed residues and therefore selectively enhances signals in 1 H-15 N correlation spectra. Binding to the polysaccharide heparin was found to induce the unfolding of preformed structural elements in OPN.


Assuntos
Ressonância Magnética Nuclear Biomolecular , Osteopontina/química , Polissacarídeos/química , Água/química , Concentração de Íons de Hidrogênio , Prótons , Solventes/química , Temperatura
13.
J Chem Phys ; 145(19): 194203, 2016 Nov 21.
Artigo em Inglês | MEDLINE | ID: mdl-27875876

RESUMO

We present novel means to hyperpolarize deuterium nuclei in 13CD2 groups at cryogenic temperatures. The method is based on cross-polarization from 1H to 13C and does not require any radio-frequency fields applied to the deuterium nuclei. After rapid dissolution, a new class of long-lived spin states can be detected indirectly by 13C NMR in solution. These long-lived states result from a sextet-triplet imbalance (STI) that involves the two equivalent deuterons with spin I = 1. An STI has similar properties as a triplet-singlet imbalance that can occur in systems with two equivalent I = 12 spins. Although the lifetimes TSTI are shorter than T1(Cz), they can exceed the life-time T1(Dz) of deuterium Zeeman magnetization by a factor of more than 20.

14.
J Phys Chem B ; 120(34): 8905-13, 2016 09 01.
Artigo em Inglês | MEDLINE | ID: mdl-27500976

RESUMO

Transverse relaxation rate measurements in magic-angle spinning solid-state nuclear magnetic resonance provide information about molecular motions occurring on nanosecond-to-millisecond (ns-ms) time scales. The measurement of heteronuclear ((13)C, (15)N) relaxation rate constants in the presence of a spin-lock radiofrequency field (R1ρ relaxation) provides access to such motions, and an increasing number of studies involving R1ρ relaxation in proteins have been reported. However, two factors that influence the observed relaxation rate constants have so far been neglected, namely, (1) the role of CSA/dipolar cross-correlated relaxation (CCR) and (2) the impact of fast proton spin flips (i.e., proton spin diffusion and relaxation). We show that CSA/D CCR in R1ρ experiments is measurable and that the CCR rate constant depends on ns-ms motions; it can thus provide insight into dynamics. We find that proton spin diffusion attenuates this CCR due to its decoupling effect on the doublet components. For measurements of dynamics, the use of R1ρ rate constants has practical advantages over the use of CCR rates, and this article reveals factors that have so far been disregarded and which are important for accurate measurements and interpretation.


Assuntos
Simulação de Dinâmica Molecular , Ressonância Magnética Nuclear Biomolecular , Proteínas/química , Anisotropia
15.
Chemistry ; 22(41): 14696-700, 2016 Oct 04.
Artigo em Inglês | MEDLINE | ID: mdl-27546550

RESUMO

Hyperpolarization is generated by dissolution dynamic nuclear polarization (d-DNP) using a polymer-based polarizing agent dubbed FLAP (filterable labeled agents for polarization). It consists of a thermo-responsive poly(N-isopropylacrylamide), also known as pNiPAM-COOH, labeled with nitroxide radicals. The polymer powder is impregnated with an arbitrary solution of interest and frozen as is. Dissolution is followed by a simple filtration, leading to hyperpolarized solutions free from any contaminants. We demonstrated the use of FLAP to hyperpolarize partially deuterated water up to P((1) H)=6 % with a long relaxation T1 >36 s characteristic of high purity. Water hyperpolarization can be transferred to drugs, metabolites, or proteins that are waiting in an NMR spectrometer, either by exchange of labile protons or through intermolecular Overhauser effects. We also show that FLAPs are suitable polarizing agents for (13) C-labeled metabolites such as pyruvate, acetate, and alanine.


Assuntos
Resinas Acrílicas/química , Proteínas/química , Água/química , Acetatos/química , Alanina/química , Isótopos de Carbono , Deutério , Radicais Livres/química , Congelamento , Espectroscopia de Ressonância Magnética , Metabolômica/métodos , Óxidos de Nitrogênio/química , Preparações Farmacêuticas/química , Prótons , Piruvatos/química , Solubilidade
17.
Infection ; 43(3): 261-6, 2015 Jun.
Artigo em Inglês | MEDLINE | ID: mdl-25690847

RESUMO

PURPOSE: Clinical presentation of tuberculosis is pleomorphic. Some forms are rare and better known by surgeons than infectious disease specialists. METHODS: We describe a rare case of isolated chronic tenosynovitis of the wrist due to Mycobacterium tuberculosis in a 66-year-old man and review similar cases in the literature. RESULTS: On literature search, only 23 other cases of tuberculous tenosynovitis were retrieved. Our case is similar, with an insidious classical presentation. The diagnosis was suggested at the surgical presentation by the presence of rice body masses. CONCLUSION: The diagnosis of tuberculous tenosynovitis should be considered in chronic tenosynovitis. Functional prognosis may be committed without adequate treatment.


Assuntos
Mãos/patologia , Mycobacterium tuberculosis/isolamento & purificação , Tenossinovite/etiologia , Tenossinovite/patologia , Tuberculose/diagnóstico , Tuberculose/patologia , Idoso , Doença Crônica , Humanos , Masculino
18.
Eur J Intern Med ; 25(8): 777-80, 2014 Oct.
Artigo em Inglês | MEDLINE | ID: mdl-25242516

RESUMO

BACKGROUND: Romiplostim and eltrombopag, the two marketed thrombopoietin receptor agonists (TPO-RAs), have distinct binding sites and might have distinct pharmacodynamic mechanisms. The aim of this study was to compare their adverse drug reaction (ADR) patterns. METHODS: We selected in the French PharmacoVigilance Database all ADRs associated with TPO-RAs from TPO-RA marketing until the 31st of December 2013. Medical charts were reviewed. We conducted disproportionality analyses comparing romiplostim exposure in the reports of a given ADR pattern (thrombosis, neurological, cutaneous, gastrointestinal or hematological) to romiplostim exposure in all other TPO-RA-related ADR reports. Reporting Odds Ratios (RORs) were adjusted for age and gender. We also compared the number of reports of a given ADR pattern per million daily defined doses (DDDs) dispensed in France during the study period. RESULTS: We described 45 reports (53 ADRs) with romiplostim and 26 reports (37 ADRs) with eltrombopag. There were 19 venous thromboses. At least one other risk factor was present in 83.3% of the cases. Ten (55.6%) patients had been splenectomized previously. There were eight arterial thromboses. Another risk factor was noticed in all cases. There was no signal for an excess risk of thrombosis with romiplostim versus eltrombopag (ROR: 1.45, 95% CI [0.48-4.45]). There was a signal for a higher risk of gastrointestinal ADRs with eltrombopag (ROR: 30.28, 95% CI [3.23-383.86]) and of hematological ADRs with romiplostim (ROR: 14.36, 95% CI [1.73-119.08]). Dispensing data-adjusted comparisons led to similar results. CONCLUSIONS: This study suggests different ADR patterns between romiplostim and eltrombopag.


Assuntos
Benzoatos/efeitos adversos , Trato Gastrointestinal/efeitos dos fármacos , Hidrazinas/efeitos adversos , Pirazóis/efeitos adversos , Receptores de Trombopoetina/agonistas , Proteínas Recombinantes de Fusão/efeitos adversos , Trombopoetina/efeitos adversos , Idoso , Feminino , França , Humanos , Masculino , Pessoa de Meia-Idade , Farmacovigilância , Receptores Fc
SELEÇÃO DE REFERÊNCIAS
DETALHE DA PESQUISA
...