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1.
J Chem Phys ; 159(14)2023 Oct 14.
Artigo em Inglês | MEDLINE | ID: mdl-37815108

RESUMO

Machine-learned interatomic potentials are fast becoming an indispensable tool in computational materials science. One approach is the ephemeral data-derived potential (EDDP), which was designed to accelerate atomistic structure prediction. The EDDP is simple and cost-efficient. It relies on training data generated in small unit cells and is fit using a lightweight neural network, leading to smooth interactions which exhibit the robust transferability essential for structure prediction. Here, we present a variety of applications of EDDPs, enabled by recent developments of the open-source EDDP software. New features include interfaces to phonon and molecular dynamics codes, as well as deployment of the ensemble deviation for estimating the confidence in EDDP predictions. Through case studies ranging from elemental carbon and lead to the binary scandium hydride and the ternary zinc cyanide, we demonstrate that EDDPs can be trained to cover wide ranges of pressures and stoichiometries, and used to evaluate phonons, phase diagrams, superionicity, and thermal expansion. These developments complement continued success in accelerated structure prediction.

2.
Phys Rev Lett ; 120(2): 023901, 2018 Jan 12.
Artigo em Inglês | MEDLINE | ID: mdl-29376703

RESUMO

Nonlinear optical processes at soft x-ray wavelengths have remained largely unexplored due to the lack of available light sources with the requisite intensity and coherence. Here we report the observation of soft x-ray second harmonic generation near the carbon K edge (∼284 eV) in graphite thin films generated by high intensity, coherent soft x-ray pulses at the FERMI free electron laser. Our experimental results and accompanying first-principles theoretical analysis highlight the effect of resonant enhancement above the carbon K edge and show the technique to be interfacially sensitive in a centrosymmetric sample with second harmonic intensity arising primarily from the first atomic layer at the open surface. This technique and the associated theoretical framework demonstrate the ability to selectively probe interfaces, including those that are buried, with elemental specificity, providing a new tool for a range of scientific problems.

3.
BMC Complement Altern Med ; 16(1): 326, 2016 Aug 30.
Artigo em Inglês | MEDLINE | ID: mdl-27576736

RESUMO

BACKGROUND: Onchocerciasis is the world's second leading infectious cause of blindness. Its control is currently hampered by the lack of a macrofilaricidal drug and by severe adverse events observed when the lone recommended microfilaricide, ivermectin is administered to individuals co-infected with Loa loa. Therefore, there is the need for a safe and effective macrofilaricidal drug that will be able to cure the infection and break transmission cycles, or at least, an alternative microfilaricide that does not kill L. loa microfilariae (mf). METHODS: Fourteen extracts from two medicinal plants, Tragia benthami and Piper umbellatum were screened in vitro against Onchocerca ochengi parasite and L. loa mf. Activities of extracts on male worms and microfilariae were assessed by motility reduction, while MTT/Formazan assay was used to assess biochemically the death of female worms. Cytotoxicity and acute toxicity of active extracts were tested on monkey kidney cells and Balb/c mice, respectively. RESULTS: At 500 µg/mL, all extracts showed 100 % activity on Onchocerca ochengi males and microfilariae, while 9 showed 100 % activity on female worms. The methylene chloride extract of Piper umbellatum leaves was the most active on adult male and female worms (IC50s: 16.63 µg/mL and 35.65 µg/mL, respectively). The three most active extracts on Onchocerca ochengi females were also highly active on Loa loa microfilariae, with IC50s of 35.12 - 13.9 µg/mL. Active extracts were generally more toxic to the worms than to cells and showed no acute toxicity to Balb/c mice. Phytochemical screening revealed the presence of saponins, steroids, tannins and flavanoids in the promising extracts. CONCLUSIONS: These results unfold potential sources of novel anti-Onchocerca lead compounds and validate the traditional use of the plants in onchocerciasis treatment.


Assuntos
Euphorbiaceae/química , Filaricidas/farmacologia , Loa/efeitos dos fármacos , Onchocerca/efeitos dos fármacos , Piper/química , Extratos Vegetais/farmacologia , Animais , Linhagem Celular , Sobrevivência Celular/efeitos dos fármacos , Filaricidas/química , Filaricidas/toxicidade , Haplorrinos , Extratos Vegetais/química , Extratos Vegetais/toxicidade
4.
Malar J ; 14: 450, 2015 Nov 14.
Artigo em Inglês | MEDLINE | ID: mdl-26574017

RESUMO

BACKGROUND: Intermittent preventive treatment (IPT) is a proven malaria control strategy in infants and pregnancy. School-aged children represent 26 % of the African population, and an increasing percentage of them are scholarized. Malaria is causing 50 % of deaths in this age group and malaria control efforts may shift the malaria burden to older age groups. Schools have been suggested as a platform for health interventions delivery (deworming, iron-folic acid, nutrients supplementation, (boost-)immunization) and as a possible delivery system for IPT in schoolchildren (IPTsc). However, the current evidence on the efficacy and safety of IPTsc is limited and the optimal therapeutic regimen remains controversial. METHODS: A systematic search for studies reporting efficacy and safety of IPT in schoolchildren was conducted using PubMed, Web of Science, Clinicaltrials and WHO/ICTRP database, and abstracts from congresses with the following key words: intermittent, preventive treatment AND malaria OR Plasmodium falciparum AND schoolchildren NOT infant NOT pregnancy. RESULTS: Five studies were identified. Most IPTsc regimes demonstrated substantial protection against malaria parasitaemia, with dihydroartemisinin-piperaquine (DP) given monthly having the highest protective effect (PE) (94 %; 95 % CI 93-96). Contrarily, SP did not provide any PE against parasitaemia. However, no IPT regimen provided a PE above 50 % in regard to anaemia, and highest protection was provided by SP+ amodiaquine (AQ) given four-monthly (50 %; 95 % CI 41-53). The best protection against clinical malaria was observed in children monthly treated with DP (97 %; 95 % CI 87-98). However, there was no protection when the drug was given three-monthly. No severe adverse events were associated with the drugs used for IPTsc. CONCLUSION: IPTsc may reduce the malaria-related burden in schoolchildren. However, more studies assessing efficacy of IPT in particular against malaria-related anaemia and clinical malaria in schoolchildren must be conducted.


Assuntos
Antimaláricos/administração & dosagem , Antimaláricos/efeitos adversos , Quimioprevenção/efeitos adversos , Quimioprevenção/métodos , Malária/prevenção & controle , Instituições Acadêmicas , Estudantes , Adolescente , África , Criança , Pré-Escolar , Humanos , Resultado do Tratamento
5.
Appl Opt ; 54(31): 9190-9, 2015 Nov 01.
Artigo em Inglês | MEDLINE | ID: mdl-26560573

RESUMO

This paper introduces temperature imaging by total-variation-based compressed sensing (CS) tomography of H2O vapor absorption spectroscopy. A controlled laboratory setup is used to generate a constant two-dimensional temperature distribution in air (a roughly Gaussian temperature profile with a central temperature of 677 K). A wavelength-tunable laser beam is directed through the known distribution; the beam is translated and rotated using motorized stages to acquire complete absorption spectra in the 1330-1365 nm range at each of 64 beam locations and 60 view angles. Temperature reconstructions are compared to independent thermocouple measurements. Although the distribution studied is approximately axisymmetric, axisymmetry is not assumed and simulations show similar performance for arbitrary temperature distributions. We study the measurement error as a function of number of beams and view angles used in reconstruction to gauge the potential for application of CS in practical test articles where optical access is limited.


Assuntos
Compressão de Dados/métodos , Termografia/instrumentação , Tomografia Óptica/instrumentação , Água/análise , Absorção Fisico-Química , Desenho de Equipamento , Análise de Falha de Equipamento , Estudos de Viabilidade , Gases/análise , Gases/química , Reprodutibilidade dos Testes , Sensibilidade e Especificidade , Análise Espectral , Temperatura , Termografia/métodos , Tomografia Óptica/métodos , Água/química
6.
Magn Reson Imaging ; 110: 1-6, 2024 Jul.
Artigo em Inglês | MEDLINE | ID: mdl-38479541

RESUMO

PURPOSE: This pilot-study aims to assess, whether quantitatively assessed enhancing breast tissue as a percentage of the entire breast volume can serve as an indicator of breast cancer at breast MRI and whether the contrast-agent employed affects diagnostic efficacy. MATERIALS: This retrospective IRB-approved study, included 39 consecutive patients, that underwent two subsequent breast MRI exams for suspicious findings at conventional imaging with 0.1 mmol/kg gadobenic and gadoteric acid. Two independent readers, blinded to the histopathological outcome, assessed unenhanced and early post-contrast images using computer-assisted software (Brevis, Siemens Healthcare). Diagnostic performance was statistically determined for percentage of ipsilateral voxel volume enhancement and for percentage of contralateral enhancing voxel volume subtracted from ipsilateral enhancing voxel volume after crosstabulation with the dichotomized histological outcome (benign/malignant). RESULTS: Ipsilateral enhancing voxel volume versus histopathological outcome resulted in an AUC of 0.707 and 0.687 for gadobenic acid, reader 1 and 2, respectively and in an AUC of 0.778 and 0.773 for gadoteric acid, reader 1 and 2, respectively. Accounting for background parenchymal enhancement by subtracting contralateral enhancing volume from ipsilateral enhancing voxel volume versus histolopathological outcome resulted in an AUC of 0.793 and 0.843 for gadobenic acid, reader 1 and 2, respectively and in an AUC of 0.692 and 0.662 for gadoteric acid, reader 1 and 2, respectively. Pairwise testing yielded no statistically significant difference both between readers and between contrast agents employed (p > 0.05). CONCLUSION: Our proposed CAD algorithm, which quantitatively assesses enhancing breast tissue as a percentage of the entire breast volume, allows indicating the presence of breast cancer.


Assuntos
Neoplasias da Mama , Mama , Meios de Contraste , Imageamento por Ressonância Magnética , Compostos Organometálicos , Humanos , Neoplasias da Mama/diagnóstico por imagem , Feminino , Projetos Piloto , Imageamento por Ressonância Magnética/métodos , Pessoa de Meia-Idade , Adulto , Estudos Retrospectivos , Idoso , Mama/diagnóstico por imagem , Interpretação de Imagem Assistida por Computador/métodos , Meglumina/análogos & derivados , Reprodutibilidade dos Testes , Algoritmos , Sensibilidade e Especificidade
7.
J Chem Theory Comput ; 19(6): 1805-1817, 2023 Mar 28.
Artigo em Inglês | MEDLINE | ID: mdl-36853624

RESUMO

Performing alchemical transformations, in which one molecular system is nonphysically changed to another system, is a popular approach adopted in performing free energy calculations associated with various biophysical processes, such as protein-ligand binding or the transfer of a molecule between environments. While the sampling of alchemical intermediate states in either parallel (e.g., Hamiltonian replica exchange) or serial manner (e.g., expanded ensemble) can bridge the high-probability regions in the configurational space between two end states of interest, alchemical methods can fail in scenarios where the most important slow degrees of freedom in the configurational space are, in large part, orthogonal to the alchemical variable, or if the system gets trapped in a deep basin extending in both the configurational and alchemical space. To alleviate these issues, we propose to use alchemical variables as an additional dimension in metadynamics, making it possible to both sample collective variables and to enhance sampling in free energy calculations simultaneously. In this study, we validate our implementation of "alchemical metadynamics" in PLUMED with test systems and alchemical processes with varying complexities and dimensionalities of collective variable space, including the interconversion between the torsional metastable states of a toy system and the methylation of a nucleoside both in the isolated form and in a duplex. We show that multidimensional alchemical metadynamics can address the challenges mentioned above and further accelerate sampling by introducing configurational collective variables. The method can trivially be combined with other metadynamics-based algorithms implemented in PLUMED. The necessary PLUMED code changes have already been released for general use in PLUMED 2.8.

8.
Nat Commun ; 14(1): 1674, 2023 Mar 25.
Artigo em Inglês | MEDLINE | ID: mdl-36966129

RESUMO

The discovery of 250-kelvin superconducting lanthanum polyhydride under high pressure marked a significant advance toward the realization of a room-temperature superconductor. X-ray diffraction (XRD) studies reveal a nonstoichiometric LaH9.6 or LaH10±Î´ polyhydride responsible for the superconductivity, which in the literature is commonly treated as LaH10 without accounting for stoichiometric defects. Here, we discover significant nuclear quantum effects (NQE) in this polyhydride, and demonstrate that a minor amount of stoichiometric defects will cause quantum proton diffusion in the otherwise rigid lanthanum lattice in the ground state. The diffusion coefficient reaches ~10-7 cm2/s in LaH9.63 at 150 gigapascals and 240 kelvin, approaching the upper bound value of interstitial hydrides at comparable temperatures. A puzzling phenomenon observed in previous experiments, the positive pressure dependence of the superconducting critical temperature Tc below 150 gigapascals, is explained by a modulation of the electronic structure due to a premature distortion of the hydrogen lattice in this quantum fluxional structure upon decompression, and resulting changes of the electron-phonon coupling. This finding suggests the coexistence of the quantum proton fluxion and hydrogen-induced superconductivity in this lanthanum polyhydride, and leads to an understanding of the structural nature and superconductivity of nonstoichiomectric hydrogen-rich materials.

9.
PLoS Negl Trop Dis ; 17(9): e0011633, 2023 09.
Artigo em Inglês | MEDLINE | ID: mdl-37721964

RESUMO

BACKGROUND: Moxidectin is a macrocyclic lactone registered for the treatment of human onchocerciasis. The drug has a good safety profile, large volume of distribution and a long elimination half-life. This paper reports tolerability data from the first use of moxidectin in persons with Wuchereria bancrofti infection. METHODS: In this randomized, open-label, masked-observer superiority trial, adults with Wuchereria bancrofti microfilaremia in Côte d'Ivoire were randomized to 1 of 4 treatment arms: ivermectin + albendazole (IA), moxidectin + albendazole (MoxA), ivermectin + diethylcarbamazine (DEC) + albendazole (IDA), or moxidectin + DEC + albendazole (MoxDA). As part of a larger efficacy trial, all participants were closely monitored for 7 days after treatment. RESULTS: One hundred sixty-four individuals were treated, and monitored for treatment emergent adverse events (TEAE). Eighty-seven participants (53%) experienced one or more mild (grade 1) or moderate (grade 2) TEAE. Four participants had transient Grade 3 hematuria after treatment (3 after IDA and 1 after IA). There were no serious adverse events. There were no significant differences in frequency or types of TEAE between treatment groups (IA = 22/41 (53%), MoxA = 24/40 (60%), IDA = 18/41 (44%), MoxDA = 15/42 (36%), p = 0.530). Fifty-nine participants (36%) had multiple TEAE, and 8.5% had a one or more grade 2 (moderate) TEAE. Grade 2 TEAE were more frequent after triple drug treatments (IDA, 14.6%; MoxDA, 9.5%) than after two-drug treatments (IA, 7.3%; MoxA, 2.5%). There was no difference in TEAEs based on baseline Mf counts (OR 0.69 (0.33, 1.43), p-value 0.319). CONCLUSION: All treatment regimens were well tolerated. We observed no difference in safety parameters between regimens that contained ivermectin or moxidectin. TRIAL REGISTRATION: Clinicaltrials.gov, NCT04410406.


Assuntos
Filariose Linfática , Filaricidas , Adulto , Animais , Humanos , Ivermectina/efeitos adversos , Filariose Linfática/tratamento farmacológico , Albendazol/efeitos adversos , Côte d'Ivoire , Wuchereria bancrofti , Quimioterapia Combinada , Dietilcarbamazina/efeitos adversos , Filaricidas/efeitos adversos
10.
Heredity (Edinb) ; 108(3): 292-301, 2012 Mar.
Artigo em Inglês | MEDLINE | ID: mdl-21897441

RESUMO

The architecture and action of quantitative trait loci (QTL) contributing to plant resistance mechanisms against aphids, the largest group of phloem-feeding insects, are not well understood. Comparative mapping of several components of resistance to the green peach aphid (Myzus persicae) was undertaken in Prunus davidiana, a wild species related to peach. An interspecific F(1) population of Prunus persica var. Summergrand × P. davidiana clone P1908 was scored for resistance (aphid colony development and foliar damage) and 17 aphid feeding behaviour traits monitored by means of the electrical penetration graph technique. Seven resistance QTLs were detected, individually explaining 6.1-43.1% of the phenotypic variation. Consistency was shown over several trials. Nine QTLs affecting aphid feeding behaviour were identified. All resistance QTLs except one co-located with QTLs underlying aphid feeding behaviour. A P. davidiana resistance allele at the major QTL was associated with drastic reductions in phloem sap ingestion by aphids, suggesting a phloem-based resistance mechanism. Resistance was also positively correlated with aphid salivation into sieve elements, suggesting an insect response to restore the appropriate conditions for ingestion after phloem occlusion. No significant QTL was found for traits characterising aphid mouthpart activity in plant tissues other than phloem vessels. Two QTLs with effects on aphid feeding behaviour but without effect on resistance were identified. SSR markers linked to the main QTLs involved in resistance are of potential use in marker-assisted selection for aphid resistance. Linking our results with the recent sequencing of the peach genome may help clarify the physiological resistance mechanisms.


Assuntos
Afídeos/fisiologia , Comportamento Alimentar , Prunus/genética , Prunus/parasitologia , Locos de Características Quantitativas , Animais , Mapeamento Cromossômico , Cromossomos de Plantas , Ordem dos Genes , Genótipo , Interações Hospedeiro-Parasita , Fenótipo , Folhas de Planta/genética
11.
Artigo em Inglês | MEDLINE | ID: mdl-36337282

RESUMO

Molecular simulations such as molecular dynamics (MD) and Monte Carlo (MC) simulations are powerful tools allowing the prediction of experimental observables in the study of systems such as proteins, membranes, and polymeric materials. The quality of predictions based on molecular simulations depend on the validity of the underlying physical assumptions. physical_validation allows users of molecular simulation programs to perform simple yet powerful tests of physical validity on their systems and setups. It can also be used by molecular simulation package developers to run representative test systems during development, increasing code correctness. The theoretical foundation of the physical validation tests were established by Merz & Shirts (2018), in which the physical_validation package was first mentioned.

12.
Int J Mol Sci ; 12(1): 376-84, 2011 Jan 14.
Artigo em Inglês | MEDLINE | ID: mdl-21339992

RESUMO

In this study, Leydig cells were purified from 70 day-old Sprague Dawley male rats and incubated with 10 and 100 µg/mL of methanol extract of Basella alba (MEBa) for 4 hours followed by the evaluation of cell viability, steroid (testosterone and estradiol) production, and the level of aromatase mRNA. Results showed that MEBa did not affect Leydig cell viability. At the concentration of 10 µg/mL, MEBa significantly stimulated testosterone and estradiol production (p < 0.01 and p < 0.03, respectively), and enhanced aromatase mRNA level (p < 0.04). These observations suggest that MEBa directly stimulated testosterone, estradiol and aromatase mRNA levels in isolated Leydig cells.


Assuntos
Células Intersticiais do Testículo/efeitos dos fármacos , Células Intersticiais do Testículo/metabolismo , Magnoliopsida/química , Metanol/química , Esteroides/biossíntese , Animais , Aromatase/genética , Células Cultivadas , Estradiol/biossíntese , Células Intersticiais do Testículo/citologia , Masculino , Extratos Vegetais/química , Extratos Vegetais/farmacologia , Ratos , Ratos Sprague-Dawley , Testosterona/biossíntese
13.
Science ; 190(4220): 1209-11, 1975 Dec 19.
Artigo em Inglês | MEDLINE | ID: mdl-1198108

RESUMO

Cystathionase activity in a lymphoid cell line extracts from a vitamin B6-responsive patient with cystathioninuria was increased strikingly by pyridoxal phosphate. Immunodiffusion with antiserum to human hepatic cystathionase showed identity between this cystathionase protein and cystathionase from an extract of normal lymphoid cells. Neither an increase in cystathionase activity nor immunochemical identity was found using extract of cells from a B6-unresponsive patient.


Assuntos
Erros Inatos do Metabolismo dos Aminoácidos/enzimologia , Cistationina gama-Liase/deficiência , Liases/deficiência , Piridoxina/uso terapêutico , Erros Inatos do Metabolismo dos Aminoácidos/tratamento farmacológico , Erros Inatos do Metabolismo dos Aminoácidos/genética , Linhagem Celular , Reações Cruzadas , Cistationina/urina , Cistationina gama-Liase/imunologia , Relação Dose-Resposta a Droga , Ativação Enzimática , Humanos , Mutação , Fosfato de Piridoxal/farmacologia
14.
PLoS One ; 13(9): e0202764, 2018.
Artigo em Inglês | MEDLINE | ID: mdl-30188933

RESUMO

Advances in recent years have made molecular dynamics (MD) and Monte Carlo (MC) simulations powerful tools in molecular-level research, allowing the prediction of experimental observables in the study of systems such as proteins, membranes, and polymeric materials. However, the quality of any prediction based on molecular dynamics results will strongly depend on the validity of underlying physical assumptions. Unphysical behavior of simulations can have significant influence on the results and reproducibility of these simulations, such as folding of proteins and DNA or properties of lipid bilayers determined by cutoff treatment, dynamics of peptides and polymers affected by the choice of thermostat, or liquid properties depending on the simulation time step. Motivated by such examples, we propose a two-fold approach to increase the robustness of molecular simulations. The first part of this approach involves tests which can be performed by the users of MD programs on their respective systems and setups. We present a number of tests of different complexity, ranging from simple post-processing analysis to more involved tests requiring additional simulations. These tests are shown to significantly increase the reliability of MD simulations by catching a number of common simulation errors violating physical assumptions, such as non-conservative integrators, deviations from the Boltzmann ensemble, and lack of ergodicity between degrees of freedom. To make the usage as easy as possible, we have developed an open-source and platform-independent Python library (https://physical-validation.readthedocs.io) implementing these tests. The second part of the approach involves testing for code correctness. While unphysical behavior can be due to poor or incompatible choices of parameters by the user, it can just as well originate in coding errors within the program. We therefore propose to include physical validation tests in the code-checking mechanism of MD software packages. We have implemented such a validation for the GROMACS software package, ensuring that every major release passes a number of physical sanity checks performed on selected representative systems before shipping. It is, to our knowledge, the first major molecular mechanics software package to run such validation routinely. The tests are, as the rest of the package, open source software, and can be adapted for other software packages.


Assuntos
Simulação de Dinâmica Molecular , Modelos Moleculares , Método de Monte Carlo , Reprodutibilidade dos Testes , Software
15.
PLoS Negl Trop Dis ; 12(6): e0006565, 2018 06.
Artigo em Inglês | MEDLINE | ID: mdl-29897908

RESUMO

BACKGROUND: Ivermectin is the only drug currently recommended for the treatment of onchocerciasis, the second leading infectious cause of blindness in the world. This drug kills only the first stage larvae-microfilariae (mf) of Onchocerca volvulus and is to be used cautiously in areas where Loa loa is prevalent because of severe adverse events observed with coinfected patients. METHODOLOGY/PRINCIPAL FINDINGS: This study investigated the anti-filarial activities of two Cameroonian medicinal plants, Lantana camara and Tamarindus indica locally used to treat onchocerciasis. Twelve (12) extracts were prepared and tested in vitro on the bovine model parasite, O. ochengi as well as L. loa mf. Both mf and adult male worm viabilities were assessed by motility scoring, while adult female worm viability was determined biochemically by standard MTT/formazan colorimetry. Cytotoxicity and acute toxicity were determined respectively, in monkey kidney epithelial cells and in BALB/c mice. Pure compounds were isolated by LC/MS using a bio-assay guided strategy. All the extracts showed 100% activity at 500 µg/mL against O. ochengi adult worms and mf. The highest activity against O. ochengi was observed with the hexane extract of L. camara leaves (LCLhex), with IC50 of 35.1 µg/mL for adult females and 3.8 µg/mL for the mf. Interestingly, this extract was more active against O. ochengi mf than L. loa mf. Further studies on the extracts led to the isolation of lantadene A from the methylene chloride extract of L. camara leaves, with IC50s of 7.85 µg/mL for adult males, 10.38 µg/mL for adult females, 10.84 µg/mL for O. ochengi mf and 20.13 µg/mL for L. loa mf. CONCLUSIONS/SIGNIFICANCE: We report for the first time the anti-onchocercal activities of these locally consumed medicinal plants and lantadene A, a potential lead for further development as an onchocerciasis cure.


Assuntos
Lantana/química , Loíase/tratamento farmacológico , Ácido Oleanólico/análogos & derivados , Oncocercose/tratamento farmacológico , Extratos Vegetais/farmacologia , Tamarindus/química , Animais , Feminino , Filaricidas/uso terapêutico , Humanos , Concentração Inibidora 50 , Loa/isolamento & purificação , Loíase/parasitologia , Masculino , Camundongos Endogâmicos BALB C , Microfilárias , Ácido Oleanólico/farmacologia , Onchocerca/isolamento & purificação , Oncocercose/parasitologia , Extratos Vegetais/química , Extratos Vegetais/isolamento & purificação , Folhas de Planta/química , Plantas Medicinais
16.
J Chem Theory Comput ; 12(8): 3825-50, 2016 Aug 09.
Artigo em Inglês | MEDLINE | ID: mdl-27248705

RESUMO

This article reports on the calibration and validation of a new GROMOS-compatible parameter set 2016H66 for small organic molecules in the condensed phase. The calibration is based on 62 organic molecules spanning the chemical functions alcohol, ether, aldehyde, ketone, carboxylic acid, ester, amine, amide, thiol, sulfide, and disulfide, as well as aromatic compounds and nucleic-acid bases. For 57 organic compounds, the calibration targets are the experimental pure-liquid density ρliq and the vaporization enthalpy ΔHvap, as well as the hydration free energy ΔGwat and the solvation free energy ΔGche in cyclohexane, at atmospheric pressure and at (or close to) room temperature. The final root-mean-square deviations (RMSD) for these four quantities over the set of compounds are 32.4 kg m(-3), 3.5 kJ mol(-1), 4.1 kJ mol(-1), and 2.1 kJ mol(-1), respectively, and the corresponding average deviations (AVED) are 1.0 kg m(-3), 0.2 kJ mol(-1), 2.6 kJ mol(-1), and 1.0 kJ mol(-1), respectively. For the five nucleic-acid bases, the parametrization is performed by transferring the final 2016H66 parameters from analogous organic compounds followed by a slight readjustment of the charges to reproduce the experimental water-to-chloroform transfer free energies ΔGtrn. The final RMSD for this quantity over the five bases is 1.7 kJ mol(-1), and the corresponding AVED is 0.8 kJ mol(-1). As an initial validation of the 2016H66 set, seven additional thermodynamic, transport, and dielectric properties are calculated for the 57 organic compounds in the liquid phase. The agreement with experiment in terms of these additional properties is found to be reasonable, with significant deviations typically affecting either a specific chemical function or a specific molecule. This suggests that in most cases, a classical force-field description along with a careful parametrization against ρliq, ΔHvap, ΔGwat, and ΔGche results in a model that appropriately describes the liquid in terms of a wide spectrum of its physical properties.

17.
FASEB J ; 17(14): 2145-7, 2003 Nov.
Artigo em Inglês | MEDLINE | ID: mdl-12958156

RESUMO

To explain why mitochondrial DNA (mtDNA)-depleted or rho0 cells still keep a mitochondrial membrane potential (Delta(psi)m) in the absence of respiration, several hypotheses have been proposed. The principal and well accepted one involves a reverse of action for ANT combined to F1-ATPase activity. However, the existence of other putative electrogenic channels has been speculated. Here, using mRNA differential display reverse transcriptase-polymerase chain reaction on L929 mtDNA-depleted cells, we identified mtCLIC as a differentially expressed gene in cells deprived from mitochondrial ATP production. Mitochondrial chloride intracellular channel (mtCLIC), a member of a recently discovered and expanding family of chloride intracellular channels, is up-regulated in mtDNA-depleted and rho0 cells. We showed that its expression is dependent on CREB and p53 and is sensitive to calcium and tumor necrosis factor alpha. Interestingly, up- or down-regulation of mtCLIC protein expression changes Delta(psi)m whereas the chloride channel inhibitor NPPB reduces the Delta(psi)m in mtDNA-depleted L929 cells, measured with the fluorescent probe rhodamine 123. Finally, we demonstrated that purified mitochondria from mtDNA-depleted cells incorporate, in a NPPB-sensitive manner, more 36chloride than parental mitochondria. These findings suggest that mtCLIC could be involved in mitochondrial membrane potential generation in mtDNA-depleted cells, a feature required to prevent apoptosis and to drive continuous protein import into mitochondria.


Assuntos
Canais de Cloreto/biossíntese , Canais de Cloreto/fisiologia , Mitocôndrias/fisiologia , Proteínas Mitocondriais/biossíntese , Proteínas Mitocondriais/fisiologia , Animais , Cálcio/fisiologia , Linhagem Celular , Proteína de Ligação ao Elemento de Resposta ao AMP Cíclico/fisiologia , DNA Mitocondrial/genética , Regulação da Expressão Gênica , Potenciais da Membrana , Camundongos , Mitocôndrias/efeitos dos fármacos , Modelos Biológicos , RNA Mensageiro/biossíntese , Regulação para Cima
18.
J Radiol ; 86(1): 76-8, 2005 Jan.
Artigo em Francês | MEDLINE | ID: mdl-15785420

RESUMO

The authors report the clinical and imaging features of a patient with rupture of an aortoiliac graft successfully treated by endovascular approach. The endovascular treatment is easy to perform and effective. The main pitfall of this technique is the limited availability of stent-grafts.


Assuntos
Aneurisma da Aorta Torácica/cirurgia , Ruptura Aórtica/cirurgia , Stents , Anastomose Cirúrgica/efeitos adversos , Aneurisma da Aorta Torácica/etiologia , Ruptura Aórtica/etiologia , Humanos , Masculino , Pessoa de Meia-Idade
19.
FEBS Lett ; 502(3): 109-12, 2001 Aug 03.
Artigo em Inglês | MEDLINE | ID: mdl-11583109

RESUMO

WI-38 human diploid fibroblasts underwent accelerated telomere shortening (490 bp/stress) and growth arrest after exposure to four subcytotoxic 100 microM tert-butylhydroperoxide (t-BHP) stresses, with a stress at every two population doublings (PD). After subcytotoxic 160 microM H2O2 stress or five repeated 30 microM t-BHP stresses along the same PD, respectively a 322 +/- 55 and 380 +/- 129 bp telomere shortening was observed only during the first PD after stress. The percentage of cells resuming proliferation after stress suggests this telomere shortening is due to the number of cell divisions accomplished to reach confluence during the first PD after stress.


Assuntos
Divisão Celular/fisiologia , Senescência Celular/fisiologia , Fibroblastos/citologia , Estresse Oxidativo , Telômero/metabolismo , Divisão Celular/efeitos dos fármacos , Diploide , Fibroblastos/efeitos dos fármacos , Fibroblastos/metabolismo , Humanos , Peróxido de Hidrogênio/farmacologia , Cinética , Timidina/química , beta-Galactosidase/metabolismo , terc-Butil Hidroperóxido/farmacologia
20.
J Neuroradiol ; 30(4): 211-8, 2003 Sep.
Artigo em Francês | MEDLINE | ID: mdl-14566188

RESUMO

Sphenoid sinusitis is uncommon, with an incidence of about 2.7%. Failure to diagnose and treat sphenoid sinus disease has been shown to lead to serious neurologic sequellae. Plain radiographs play a limited role in the management of sinusitis. CT scan can provide a positive diagnosis by the visualization of mucosal thickening, air-fluid level and complete opacification of the sinusal cavities. In addition, CT can provide more information about the anatomy and abnormalities of the sphenoid sinus. MRI is used in cases of suspected tumors or neurologic involvement. The most common presenting symptom is headache that arise characteristically, but rarely, from the vertex. Sphenoiditis has a high risk of severe neurologic involvement, cavernous sinus thrombosis being one of the most serious complications.


Assuntos
Osso Esfenoide/diagnóstico por imagem , Osso Esfenoide/patologia , Sinusite Esfenoidal/diagnóstico , Trombose do Corpo Cavernoso/etiologia , Diagnóstico Diferencial , Cefaleia/complicações , Humanos , Imageamento por Ressonância Magnética , Osso Esfenoide/anormalidades , Sinusite Esfenoidal/complicações , Tomografia Computadorizada por Raios X
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