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1.
Nature ; 536(7614): 54-7, 2016 08 04.
Artículo en Inglés | MEDLINE | ID: mdl-27362221

RESUMEN

The typically dark surface of the dwarf planet Ceres is punctuated by areas of much higher albedo, most prominently in the Occator crater. These small bright areas have been tentatively interpreted as containing a large amount of hydrated magnesium sulfate, in contrast to the average surface, which is a mixture of low-albedo materials and magnesium phyllosilicates, ammoniated phyllosilicates and carbonates. Here we report high spatial and spectral resolution near-infrared observations of the bright areas in the Occator crater on Ceres. Spectra of these bright areas are consistent with a large amount of sodium carbonate, constituting the most concentrated known extraterrestrial occurrence of carbonate on kilometre-wide scales in the Solar System. The carbonates are mixed with a dark component and small amounts of phyllosilicates, as well as ammonium carbonate or ammonium chloride. Some of these compounds have also been detected in the plume of Saturn's sixth-largest moon Enceladus. The compounds are endogenous and we propose that they are the solid residue of crystallization of brines and entrained altered solids that reached the surface from below. The heat source may have been transient (triggered by impact heating). Alternatively, internal temperatures may be above the eutectic temperature of subsurface brines, in which case fluids may exist at depth on Ceres today.

2.
Nature ; 528(7581): 241-4, 2015 Dec 10.
Artículo en Inglés | MEDLINE | ID: mdl-26659184

RESUMEN

Studies of the dwarf planet (1) Ceres using ground-based and orbiting telescopes have concluded that its closest meteoritic analogues are the volatile-rich CI and CM carbonaceous chondrites. Water in clay minerals, ammoniated phyllosilicates, or a mixture of Mg(OH)2 (brucite), Mg2CO3 and iron-rich serpentine have all been proposed to exist on the surface. In particular, brucite has been suggested from analysis of the mid-infrared spectrum of Ceres. But the lack of spectral data across telluric absorption bands in the wavelength region 2.5 to 2.9 micrometres--where the OH stretching vibration and the H2O bending overtone are found--has precluded definitive identifications. In addition, water vapour around Ceres has recently been reported, possibly originating from localized sources. Here we report spectra of Ceres from 0.4 to 5 micrometres acquired at distances from ~82,000 to 4,300 kilometres from the surface. Our measurements indicate widespread ammoniated phyllosilicates across the surface, but no detectable water ice. Ammonia, accreted either as organic matter or as ice, may have reacted with phyllosilicates on Ceres during differentiation. This suggests that material from the outer Solar System was incorporated into Ceres, either during its formation at great heliocentric distance or by incorporation of material transported into the main asteroid belt.

3.
Nature ; 504(7478): 122-5, 2013 Dec 05.
Artículo en Inglés | MEDLINE | ID: mdl-24196707

RESUMEN

Olivine is a major component of the mantle of differentiated bodies, including Earth. Howardite, eucrite and diogenite (HED) meteorites represent regolith, basaltic-crust, lower-crust and possibly ultramafic-mantle samples of asteroid Vesta, which is the lone surviving, large, differentiated, basaltic rocky protoplanet in the Solar System. Only a few of these meteorites, the orthopyroxene-rich diogenites, contain olivine, typically with a concentration of less than 25 per cent by volume. Olivine was tentatively identified on Vesta, on the basis of spectral and colour data, but other observations did not confirm its presence. Here we report that olivine is indeed present locally on Vesta's surface but that, unexpectedly, it has not been found within the deep, south-pole basins, which are thought to be excavated mantle rocks. Instead, it occurs as near-surface materials in the northern hemisphere. Unlike the meteorites, the olivine-rich (more than 50 per cent by volume) material is not associated with diogenite but seems to be mixed with howardite, the most common surface material. Olivine is exposed in crater walls and in ejecta scattered diffusely over a broad area. The size of the olivine exposures and the absence of associated diogenite favour a mantle source, but the exposures are located far from the deep impact basins. The amount and distribution of observed olivine-rich material suggest a complex evolutionary history for Vesta.

4.
Sci Data ; 11(1): 118, 2024 Jan 24.
Artículo en Inglés | MEDLINE | ID: mdl-38267452

RESUMEN

Chinese lunar landing mission Chang'E-4 reached the far side of the Moon in January 2019 and has been providing unprecedented Lunar Penetrating Radar data able to explore the lunar subsurface down to more than 40 m (with its more resolutive high frequency band). Data are periodically released to the scientific community in raw PDS4 format. Here we provide different versions of the radar dataset after editing (i.e. pre-processing), partial, and full processing in order to provide a complete ready-to-use dataset to end-users (data collected since 4th January 2019 until 27th March 2023) which can be directly exploited for analysis, interpretation, inversion, as well as integration with imagery or other information. In particular, we implemented an efficient and objective way to remove duplicated traces representing more than 90% of original data, as well as a processing flow able to retain all the original data information, while avoiding redundancies. The provided datasets can be implemented with future data releases and straightforwardly exploited for any future analysis.

5.
J Microbiol Methods ; 224: 107003, 2024 Jul 20.
Artículo en Inglés | MEDLINE | ID: mdl-39038560

RESUMEN

The reduction of antimicrobial susceptibility testing (AST) time-to-result is a central need, especially in sepsis treatment. The current automated rapid ASTs are still too expensive for many laboratories. We aimed to evaluate three pre-treatment methods for a same-day inoculation on both automated AST platforms available in our laboratory. We tested 100 Enterobacterales or staphylococci positive bottles. We obtained good results with the different methods and instruments. In particular, Vitek-2 showed good performances with Enterobacterales AST when inoculated with bacterial pellet (96.6% categorical agreement - CA-, 93.3% essential agreement - EA). Also short-term incubation colonies for staphylococci AST had acceptable CA (94.2%), even if with 77.5% EA. MicroScan system for staphylococci AST with both short-term incubation and direct blood inoculation reached >95% CA, but 92.5% and 83.6% EA, respectively. On the other hand, Enterobacterales AST showed optimal performances only with bacterial pellet inoculation (97.6% CA). In fact, direct blood inoculation showed not acceptable parameters for several molecules. Both systems allow a 24-h reduction in time-to-result, by using the same instruments of routine activity after rapid and cheap pre-treatments.

6.
Astrobiology ; 23(6): 691-704, 2023 06.
Artículo en Inglés | MEDLINE | ID: mdl-37126783

RESUMEN

The Mars Multispectral Imager for Subsurface Studies (Ma_MISS) instrument is a miniaturized visible and near-infrared spectrometer that is integrated into the drilling system of the ESA Rosalind Franklin rover, which is devoted to subsurface exploration on Mars. Ma_MISS will acquire spectral data on the Martian subsurface from excavated borehole walls. The spectral data collected by Ma_MISS on unexposed rocks will be crucial for determination of the composition of subsurface rocks and optical and physical properties of materials (i.e., grain size). Ma_MISS will further contribute to a reconstruction of the stratigraphic column and acquire data on subsurface geological processes. Ma_MISS data may also inform with regard to the presence of potential biomarkers in the subsurface, given the presence of organic matter that may affect some spectral parameters. In this framework, we performed a wide range of measurements using the laboratory model of the Ma_MISS to investigate mineral/organic mixtures in different proportions. We prepared mixtures by combining kaolinite and nontronite with glycine, asphaltite, polyoxymethylene, and benzoic acid. These organic compounds show different spectral characteristics in the visible and near-infrared; therefore their presence can be detected by the Ma_MISS instrument. Our results indicate that the Ma_MISS instrument can detect organic material down to abundances of around 1 wt %. In particular, the data collected on low-concentration mixtures show that, by analyzing sediments with a grain size smaller than the Ma_MISS spatial resolution, the instrument can still discern those points where organic matter is present from points with exclusive mineral composition. The results also show that a collection of multiple contiguous measurements on a hypothetical borehole wall could help indicate the presence of organic matter in clay-rich soils if present.


Asunto(s)
Medio Ambiente Extraterrestre , Marte , Exobiología/métodos , Minerales , Fenómenos Geológicos
7.
Rev Sci Instrum ; 94(9)2023 Sep 01.
Artículo en Inglés | MEDLINE | ID: mdl-37655988

RESUMEN

The Ma_MISS miniaturized spectrometer is integrated within the Drilling System of the ExoMars Rosalind Franklin Rover for Mars exploration. Here we focus on the on ground calibration campaign to obtain radiometric and linearity calibrations of the Ma_MISS instrument, while the first paper dealt with the spectral calibration [De Angelis et al., Rev. Sci. Instrum. 93, 123704 (2022)]. The experimental setup used to carry out radiometric calibration is described, as are the methods used for data processing and key parameter retrieval. In particular, the Spectrometer Transfer Function (Responsivity), Signal-to-Noise Ratio, and detector linearity are determined. In a third paper [De Sanctis et al., Planet. Sci. J. 3, 142 (2022)], validation of the Ma_MISS calibration results through spectral measurements performed on rock and synthetic targets during the radiometric calibration campaign is described.

8.
J Neurol Neurosurg Psychiatry ; 82(12): 1355-9, 2011 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-21622936

RESUMEN

BACKGROUND: The identification of biomarkers able to improve the differential diagnosis between multiple sclerosis (MS) and neuromyelitis optica (NMO) is challenging because of a different prognosis and response to treatment. Growing evidence indicates that brain and CSF N-acetyl aspartate (NAA) concentration is a useful marker for characterising different phases of axonal pathology in demyelinating diseases, and preliminary studies suggest that increased serum NAA levels may be a telltale sign of acute neuronal damage or defective NAA metabolism in oligodendrocytes. OBJECTIVE: To evaluate whether serum and CSF NAA concentration differs in patients with MS and NMO. DESIGN: Observational, multicentre, prospective, cross sectional study. METHODS: Serum samples were collected from 48 relapsing-remitting MS, 32 NMO and 76 age matched healthy controls. Coeval CSF samples were available for all MS and for 8/32 NMO patients. NAA was measured in serum and CSF by liquid chromatography-mass spectrometry. RESULTS: MS patients showed higher serum and CSF NAA levels than NMO patients, and higher serum NAA levels than healthy controls (p<0.001). High serum NAA values, exceeding the 95th percentile of serum NAA values in healthy controls, were found in 100% of patients with MS and in no patient with NMO. No differences in serum NAA levels were found between NMO and healthy controls. In MS, serum and CSF NAA levels correlated with disability score. CONCLUSIONS: Determination of serum and CSF NAA levels may represent a suitable tool in the diagnostic laboratory workup to differentiate MS and NMO.


Asunto(s)
Ácido Aspártico/análogos & derivados , Esclerosis Múltiple Recurrente-Remitente/diagnóstico , Neuromielitis Óptica/diagnóstico , Adolescente , Adulto , Anciano , Ácido Aspártico/sangre , Ácido Aspártico/líquido cefalorraquídeo , Biomarcadores/sangre , Biomarcadores/líquido cefalorraquídeo , Estudios de Casos y Controles , Diagnóstico Diferencial , Femenino , Humanos , Masculino , Persona de Mediana Edad , Esclerosis Múltiple Recurrente-Remitente/sangre , Esclerosis Múltiple Recurrente-Remitente/líquido cefalorraquídeo , Neuromielitis Óptica/sangre , Neuromielitis Óptica/líquido cefalorraquídeo
9.
Rev Sci Instrum ; 91(12): 123102, 2020 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-33379964

RESUMEN

This work describes the correction method applied to the dataset acquired at the asteroid (4) Vesta by the visible channel of the visible and infrared mapping spectrometer. The rising detector temperature during data acquisitions in the visible wavelengths leads to a spectral slope increase over the whole spectral range. This limits the accuracy of the studies of the Vesta surface in this wavelength range. Here, we detail an empirical method to correct for the visible detector temperature dependency while taking into account the specificity of the Vesta dataset.

10.
J Cell Biol ; 125(4): 803-15, 1994 May.
Artículo en Inglés | MEDLINE | ID: mdl-7514605

RESUMEN

CHIP28 is a 28-kD hydrophobic integral membrane protein that functions as a water channel in erythrocytes and renal tubule epithelial cell membranes. We examined the transmembrane topology of CHIP28 in the ER by engineering a reporter of translocation (derived from bovine prolactin) into nine sequential sites in the CHIP28 coding region. The resulting chimeras were expressed in Xenopus oocytes, and the topology of the reporter with respect to the ER membrane was determined by protease sensitivity. We found that although hydropathy analysis predicted up to seven potential transmembrane regions, CHIP28 spanned the membrane only four times. Two putative transmembrane helices, residues 52-68 and 143-157, reside on the lumenal and cytosolic surfaces of the ER membrane, respectively. Topology derived from these chimeric proteins was supported by cell-free translation of five truncated CHIP28 cDNAs, by N-linked glycosylation at an engineered consensus site in native CHIP28 (residue His69), and by epitope tagging of the CHIP28 amino terminus. Defined protein chimeras were used to identify internal sequences that direct events of CHIP28 topogenesis. A signal sequence located within the first 52 residues initiated nascent chain translocation into the ER lumen. A stop transfer sequence located in the hydrophobic region from residues 90-120 terminated ongoing translocation. A second internal signal sequence, residues 155-186, reinitiated translocation of a COOH-terminal domain (residues 186-210) into the ER lumen. Integration of the nascent chain into the ER membrane occurred after synthesis of 107 residues and required the presence of two membrane-spanning regions. From this data, we propose a structural model for CHIP28 at the ER membrane in which four membrane-spanning alpha-helices form a central aqueous channel through the lipid bilayer and create a pathway for water transport.


Asunto(s)
Acuaporinas , Retículo Endoplásmico/metabolismo , Canales Iónicos/biosíntesis , Agua , Secuencia de Aminoácidos , Animales , Acuaporina 1 , Secuencia de Bases , Transporte Biológico , Bovinos , Membrana Celular/química , Sistema Libre de Células , Citosol/química , ADN , Glicosilación , Canales Iónicos/química , Canales Iónicos/genética , Datos de Secuencia Molecular , Biosíntesis de Proteínas , Conformación Proteica , Agua/química , Xenopus
11.
Rev Sci Instrum ; 90(12): 123110, 2019 Dec 01.
Artículo en Inglés | MEDLINE | ID: mdl-31893819

RESUMEN

Data acquired at Ceres by the visible channel of the Visible and InfraRed mapping spectrometer (VIR) on board the NASA Dawn spacecraft are affected by the temperatures of both the visible (VIS) and the infrared (IR) sensors, which are, respectively, a charged coupled device and a HgCdTe array. The variations of the visible channel temperatures measured during the sessions of acquisitions are correlated with the variations in the spectral slope and shape for all the mission phases. The IR channel temperature is more stable during the acquisitions; nonetheless, it is characterized by a bimodal distribution whether the cryocooler (and, therefore, the IR channel) is used or not during the visible channel operations. When the infrared channel temperature is high (175 K, i.e., not in use and with the cryocooler off), an additional negative slope and a distortion are observed in the spectra of the visible channel. We developed an empirical correction based on a reference spectrum for the whole dataset; it is designed to correct the two issues related to the sensor temperatures that we have identified. The reference spectrum is calculated to be representative of the global Ceres' surface. It is also made of the data acquired when the visible and infrared channel temperatures are equal to the ones measured during an observation of the Arcturus star by VIR, which is consistent with several ground-based observations. The developed correction allows reliable analysis and mapping to be performed by minimizing the artifacts induced by fluctuations of the VIS temperature. Thanks to this correction, a direct comparison between different mission phases during which the VIR experienced different visible and infrared channel temperatures is now possible.

12.
Science ; 361(6401): 490-493, 2018 08 03.
Artículo en Inglés | MEDLINE | ID: mdl-30045881

RESUMEN

The presence of liquid water at the base of the martian polar caps has long been suspected but not observed. We surveyed the Planum Australe region using the MARSIS (Mars Advanced Radar for Subsurface and Ionosphere Sounding) instrument, a low-frequency radar on the Mars Express spacecraft. Radar profiles collected between May 2012 and December 2015 contain evidence of liquid water trapped below the ice of the South Polar Layered Deposits. Anomalously bright subsurface reflections are evident within a well-defined, 20-kilometer-wide zone centered at 193°E, 81°S, which is surrounded by much less reflective areas. Quantitative analysis of the radar signals shows that this bright feature has high relative dielectric permittivity (>15), matching that of water-bearing materials. We interpret this feature as a stable body of liquid water on Mars.

13.
J Clin Invest ; 97(3): 664-71, 1996 Feb 01.
Artículo en Inglés | MEDLINE | ID: mdl-8609221

RESUMEN

Water movement across the airway epithelium is important for regulation of the volume and composition of airspace fluid. A novel approach is reported here to measure osmotic and diffusional water permeability in intact airways. Small airways (100-200 microns diameter, 1-2 mm length) from guinea pig lung were microdissected and perfused in vitro using concentric glass holding and perfusion pipettes. For measurement of osmotic water permeability (Pf), the airway lumen was perfused wit PBS (300 mOsM) containing a membrane impermeable fluorophore, fluorescein sulfonate (FS), and the airway was bathed in solutions of specified osmolalities. Pf determination was based on the changes in FS fluorescence at the distal end of the airway resulting from transepithelial water transport. Pf was 4-5 x 10(-3) cm/s at 23 degrees C and independent of lumen flow rate (10-100 nl/min) and the magnitude and direction of the osmotic gradient (bath osmolality 50-600 mOsM). Temperature dependence measurements gave an activation energy of 4.4 kcal/mol (15-37 degrees C). Pf was not altered by 0.3 mM HgCl2 or 50 microM forskolin, but was increased to 31 x 10(-3) cm/s by 100 micrograms/ml amphotericin B, indicating that osmosis is not limited by unstirred layers. Diffusional water permeability (Pd) was measured by H2O/D2O (deuterium oxide) exchange using the H2O/D2O-sensitive fluorescent probe aminonapthelane trisulfonic acid in the lumen. Measured Pd was 3-6 x 10(-6) cm/s at 23 degrees C, indicating significant restriction to water diffusion by unstirred layers. Antibody localization of water channels showed strong expression of the mercurial-insensitive water channel (AQP-4) at the basolateral membrane of airway epithelial cells. These results provide functional evidence that water movement across the distal airway epithelium is mediated by water channels.


Asunto(s)
Canales Iónicos/metabolismo , Sistema Respiratorio/metabolismo , Agua/metabolismo , Animales , Difusión , Fluoresceínas , Colorantes Fluorescentes , Cobayas , Inmunohistoquímica , Canales Iónicos/aislamiento & purificación , Ósmosis , Perfusión/instrumentación , Permeabilidad , Ácidos Sulfónicos
14.
J Clin Invest ; 102(4): 695-703, 1998 Aug 15.
Artículo en Inglés | MEDLINE | ID: mdl-9710437

RESUMEN

In this study we analyzed the expression of aquaporin-4 (AQP4) in mammalian skeletal muscle. Immunohistochemical experiments revealed that affinity-purified AQP4 antibodies stained selectively the sarcolemma of fast-twitch fibers. By immunogold electron microscopy, little or no intracellular labeling was detected. Western blot analysis showed the presence of two immunopositive bands with apparent molecular masses of 30 and 32 kD specifically present in membrane fraction of a fast-twitch rat skeletal muscle (extensor digitorum longus, EDL) and not revealed in a slow-twitch muscle (soleus). PCR Southern blot experiments resulted in a selective amplification in EDL of a 960-bp cDNA fragment encoding for the full-length rat form of AQP4. Functional experiments carried out on isolated skeletal muscle bundle fibers demonstrated that the osmotic response is faster in EDL than in soleus fibers isolated from the same rat. These results provide for the first time evidence for the expression of an aquaporin in skeletal muscle correlated to a specific fiber-type metabolism. Furthermore, we have analyzed AQP4 expression in skeletal muscle of mdx mice in which a decreased density of orthogonal arrays of particles, a typical morphological feature of AQP4, has been reported. Immunofluorescence experiments showed a marked reduction of AQP4 expression suggesting a critical role in the membrane alteration of Duchenne muscular dystrophy.


Asunto(s)
Acuaporinas , Canales Iónicos/análisis , Fibras Musculares de Contracción Rápida/química , Músculo Esquelético/química , Animales , Acuaporina 4 , Compartimento Celular , Expresión Génica , Inmunohistoquímica , Músculos Intercostales/química , Canales Iónicos/genética , Masculino , Fibras Musculares de Contracción Lenta/química , Ósmosis , Reacción en Cadena de la Polimerasa , ARN Mensajero/análisis , Ratas , Ratas Wistar , Sarcolema/química , Distribución Tisular , Equilibrio Hidroelectrolítico
15.
Science ; 355(6326): 719-722, 2017 02 17.
Artículo en Inglés | MEDLINE | ID: mdl-28209893

RESUMEN

Organic compounds occur in some chondritic meteorites, and their signatures on solar system bodies have been sought for decades. Spectral signatures of organics have not been unambiguously identified on the surfaces of asteroids, whereas they have been detected on cometary nuclei. Data returned by the Visible and InfraRed Mapping Spectrometer on board the Dawn spacecraft show a clear detection of an organic absorption feature at 3.4 micrometers on dwarf planet Ceres. This signature is characteristic of aliphatic organic matter and is mainly localized on a broad region of ~1000 square kilometers close to the ~50-kilometer Ernutet crater. The combined presence on Ceres of ammonia-bearing hydrated minerals, water ice, carbonates, salts, and organic material indicates a very complex chemical environment, suggesting favorable environments to prebiotic chemistry.

16.
Br J Pharmacol ; 149(7): 909-19, 2006 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-17031388

RESUMEN

BACKGROUND AND PURPOSE: Skeletal muscle injury by hypolipidemic drugs is not fully understood. An extensive analysis of the effect of chronic treatment with fluvastatin (5 mgkg(-1) and 20 mgkg(-1)), atorvastatin (10 mgkg(-1)) and fenofibrate (60 mgkg(-1)) on rat skeletal muscle was undertaken. EXPERIMENTAL APPROACH: Myoglobinemia as sign of muscle damage was measured by enzymatic assay. Histological and immunohistochemical techniques were used to estimate muscle integrity and the presence of aquaporin-4, a protein controlling water homeostasis. Electrophysiological evaluation of muscle Cl(-) conductance (gCl) and mechanical threshold (MT) for contraction, index of intracellular calcium homeostasis, was performed by the two-intracellular microelectrodes technique. KEY RESULTS: Fluvastatin (20 mgkg(-1)) increased myoglobinemia. The lower dose of fluvastatin did not modify myoglobinemia, but reduced urinary electrolytes, suggesting direct effects on renal function. Atorvastatin also increased myoglobinemia, with slight effects on urinary parameters. No treatment caused any histological damage to muscle or modification in the number of fibres expressing aquaporin-4. Either fluvastatin (at both doses) or atorvastatin reduced sarcolemma gCl and changed MT. Both statins produced slight effects on total cholesterol, suggesting that the observed modifications occur independently of HMGCoA-reductase inhibition. Fenofibrate increased myoglobinemia and decreased muscle gCl, whereas it did not change the MT, suggesting a different mechanism of action from the statins. CONCLUSIONS AND IMPLICATIONS: This study identifies muscle gCl and MT as early targets of drugs action that may contribute to milder symptoms of myotoxicity, such as muscle cramps, while the increase of myoglobinemia is a later phenomenon.


Asunto(s)
Fenofibrato/toxicidad , Inhibidores de Hidroximetilglutaril-CoA Reductasas/toxicidad , Hipolipemiantes/toxicidad , Fibras Musculares de Contracción Rápida/efectos de los fármacos , Músculo Esquelético/efectos de los fármacos , Potenciales de Acción/efectos de los fármacos , Animales , Acuaporina 4/análisis , Atorvastatina , Peso Corporal/efectos de los fármacos , Canales de Cloruro/efectos de los fármacos , Relación Dosis-Respuesta a Droga , Ingestión de Alimentos/efectos de los fármacos , Ácidos Grasos Monoinsaturados/toxicidad , Fluvastatina , Ácidos Heptanoicos/toxicidad , Indoles/toxicidad , Enfermedades Renales/inducido químicamente , Lípidos/sangre , Masculino , Potenciales de la Membrana/efectos de los fármacos , Contracción Muscular/efectos de los fármacos , Fibras Musculares de Contracción Rápida/química , Fibras Musculares de Contracción Rápida/patología , Músculo Esquelético/patología , Músculo Esquelético/fisiopatología , Enfermedades Musculares/inducido químicamente , Cadenas Pesadas de Miosina/análisis , Tamaño de los Órganos/efectos de los fármacos , Pirroles/toxicidad , Ratas , Ratas Wistar , Rabdomiólisis/inducido químicamente , Factores de Tiempo
17.
Cell Mol Biol (Noisy-le-grand) ; 52(7): 51-6, 2006 Oct 30.
Artículo en Inglés | MEDLINE | ID: mdl-17543222

RESUMEN

Aquaporin-1 (AQP1) is a water channel protein mainly expressed in endothelial and epithelial cells of many tissues, including the vasculature where it serves to increase cell membrane water permeability. Previous studies in active multiple myeloma patients and in AQP1 KO mice indicated an involvement of AQP1 in physiological and tumor angiogenesis. To understand the physiological role of AQP1 in angiogenesis, we used a 21-nucleotide small interfering RNA duplexes (siRNA) to knockdown AQP1 in the chick embryo chorioallantoic membrane (CAM), a commonly used in vivo assay to study both angiogenic and angiostatic molecules. Chicken AQP1 sequence was identified and utilized to synthesize a siRNA directed to the AQP1 sequence. We then tested the efficiency of the siRNA in vitro, using an AQP1 transfected cell line. The level of AQP1 protein reduction obtained using siRNA was 98 % and 92 % after 1 and 2 day transfection respectively. RNA interference experiments were then performed in vivo by using the CAM assay. Results showed that after 4 days of treatment, AQP1 siRNA was able to strongly inhibit angiogenesis. This is the first study showing the in vivo use of RNA interference technique in the CAM assay. Our results strongly support the hypothesis that AQP1 could have a key role in physiological and pathological angiogenesis.


Asunto(s)
Acuaporina 1/fisiología , Membrana Corioalantoides/metabolismo , Silenciador del Gen , Neovascularización Fisiológica/fisiología , Interferencia de ARN , Animales , Acuaporina 1/genética , Emparejamiento Base , Secuencia de Bases , Western Blotting , Embrión de Pollo , Clonación Molecular , Biología Computacional , Cartilla de ADN , Microscopía Fluorescente , Datos de Secuencia Molecular , Neovascularización Fisiológica/genética , ARN Interferente Pequeño/genética , Reacción en Cadena de la Polimerasa de Transcriptasa Inversa , Análisis de Secuencia de ADN
18.
Science ; 353(6303)2016 09 02.
Artículo en Inglés | MEDLINE | ID: mdl-27701086

RESUMEN

The dwarf planet Ceres is known to host phyllosilicate minerals at its surface, but their distribution and origin have not previously been determined. We used the spectrometer onboard the Dawn spacecraft to map their spatial distribution on the basis of diagnostic absorption features in the visible and near-infrared spectral range (0.25 to 5.0 micrometers). We found that magnesium- and ammonium-bearing minerals are ubiquitous across the surface. Variations in the strength of the absorption features are spatially correlated and indicate considerable variability in the relative abundance of the phyllosilicates, although their composition is fairly uniform. These data, along with the distinctive spectral properties of Ceres relative to other asteroids and carbonaceous meteorites, indicate that the phyllosilicates were formed endogenously by a globally widespread and extensive alteration process.

19.
Semin Oncol ; 28(6): 543-50, 2001 Dec.
Artículo en Inglés | MEDLINE | ID: mdl-11740807

RESUMEN

Factor VIII-related antigen (FVIII-RA)-positive microvessel areas were measured by both immunohistochemistry and computerized image analysis in patients with active multiple myeloma (MM), nonactive MM, and monoclonal gammopathies of undetermined significance (MGUS). A five-to sixfold larger area was found in patients with active MM compared to the other two groups. Aquaporin 1 (AQP1)-positive microvessel areas, measured with the same techniques on adjacent tissue sections, were also increased in active MM, and tended to be larger than and closely correlated with the FVIII-RA areas. Numerous mast cells were found in the bone marrow of active MM patients, and counts were strictly correlated with the microvessel density. The conditioned medium (CM) of bone marrow plasma cells from active MM patients stimulated endothelial cell proliferation and chemotaxis, monocyte chemotaxis, and angiogenesis in vivo (assessed by the chick embryo chorioallantoic membrane [CAM] system) more strongly and frequently than the CM of patients with nonactive MM and MGUS. Immunoassay of plasma cell lysates gave significantly higher levels of fibroblast growth factor-2 (FGF-2) in patients with active MM than in the other two groups, and a neutralizing anti-FGF-2 antibody inhibited by 46% to 68% the biological activity exerted by the CM in vitro and in the CAM. In situ hybridization of bone marrow plasma cells and zymography of CM showed that patients with active MM express higher levels of matrix metalloproteinase-2 (MMP-2) mRNA and protein than those with nonactive MM and MGUS, whereas MMP-9 expression and secretion overlapped in all groups. Overall data indicate that patients with active MM represent the vascular phase of plasma cell tumors that is induced, at least partly, through FGF-2 and MMP-2. Mast cells possibly contribute to the vascular phase via angiogenic factors in their secretory granules. Both angiogenesis and MMP-2 secretion can account for intramedullary and extramedullary spreading of plasma cells in patients with active MM.


Asunto(s)
Médula Ósea/irrigación sanguínea , Mieloma Múltiple/patología , Inductores de la Angiogénesis/metabolismo , Acuaporina 1 , Acuaporinas/metabolismo , Antígenos de Grupos Sanguíneos , Médula Ósea/metabolismo , Factor 2 de Crecimiento de Fibroblastos/metabolismo , Humanos , Técnicas para Inmunoenzimas , Mastocitos/metabolismo , Metaloproteinasa 2 de la Matriz/metabolismo , Metaloproteinasa 9 de la Matriz/metabolismo , Mieloma Múltiple/irrigación sanguínea , Mieloma Múltiple/metabolismo , Neovascularización Patológica , Paraproteinemias/metabolismo , Paraproteinemias/patología , Pronóstico , Tromboplastina/metabolismo
20.
Neuroscience ; 125(4): 921-35, 2004.
Artículo en Inglés | MEDLINE | ID: mdl-15120852

RESUMEN

In order to ascertain whether the alterations of the blood-brain barrier (BBB) seen in adult dystrophic mdx-mice [Glia 42 (2003) 235], a human model of Duchenne muscular dystrophy (DMD), are developmentally established and correlated with other dystrophin isoforms which are localized at the glial-vascular interface, we used immunocytochemistry to investigate the expression of dystrophin isoforms (Dp71) during BBB development in mdx fetuses and in adult mice. Parallelly, we used Western blot, immunocytochemistry and immunogold electron microscopy to analyze the expression of the zonula occludens (ZO-1), aquaporin-4 (AQP4) and glial fibrillary acidic (GFAP) proteins as endothelial and glial markers, and we evaluated the integrity of the mdx BBB by means of intravascular injection of horseradish peroxidase (HRP). The results show reduced dystrophin isoforms (Dp71) in the mdx mouse compared with the control, starting from early embryonic life. Endothelial ZO-1 expression was reduced, and the tight junctions were altered and unlabeled. AQP4 and GFAP glial proteins in mdx mice also showed modifications in developmental expression, the glial vascular processes being only lightly AQP4- and GFAP-labeled compared with the controls. Confocal microscopy and HRP assays confirmed the alteration in vessel glial investment, GFAP perivascular endfoot reactivity being strongly reduced and BBB permeability increasing. These results demonstrate that a reduction in dystrophin isoforms (Dp71) at glial endfeet leads to an altered development of the BBB, whose no-closure might contribute to the neurological dysfunctions associated with DMD.


Asunto(s)
Barrera Hematoencefálica/crecimiento & desarrollo , Barrera Hematoencefálica/patología , Distrofia Muscular Animal/patología , Animales , Acuaporina 4 , Acuaporinas/biosíntesis , Barrera Hematoencefálica/ultraestructura , Western Blotting , Distrofina/biosíntesis , Electroforesis en Gel de Poliacrilamida , Feto , Proteína Ácida Fibrilar de la Glía/biosíntesis , Inmunohistoquímica , Proteínas de la Membrana/biosíntesis , Ratones , Ratones Endogámicos mdx , Microscopía Confocal , Microscopía Inmunoelectrónica , Fosfoproteínas/biosíntesis , Isoformas de Proteínas/biosíntesis , Uniones Estrechas/metabolismo , Uniones Estrechas/patología , Uniones Estrechas/ultraestructura , Proteína de la Zonula Occludens-1
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