Correction of the VIR-visible dataset from the Dawn mission at Vesta.

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.

Close Cassini flybys of Saturn's ring moons Pan, Daphnis, Atlas, Pandora, and Epimetheus.

Saturn's main ring system is associated with a set of small moons that either are embedded within it or interact with the rings to alter their shape and composition. Five close flybys of the moons Pan, Daphnis, Atlas, Pandora, and Epimetheus were performed between December 2016 and April 2017 during the ring-grazing orbits of the Cassini mission. Data on the moons' morphology, structure, particle environment, and composition were returned, along with images in the ultraviolet and thermal infrared. We find that the optical properties of the moons' surfaces are determined by two competing processes: contamination by a red material formed in Saturn's main ring system and accretion of bright icy particles or water vapor from volcanic plumes originating on the moon Enceladus.

Correction of the VIR-visible data set from the Dawn mission.

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.

Localized aliphatic organic material on the surface of Ceres.

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.

Seasonal exposure of carbon dioxide ice on the nucleus of comet 67P/Churyumov-Gerasimenko.

Carbon dioxide (CO2) is one of the most abundant species in cometary nuclei, but because of its high volatility, CO2 ice is generally only found beneath the surface. We report the infrared spectroscopic identification of a CO2 ice-rich surface area located in the Anhur region of comet 67P/Churyumov-Gerasimenko. Spectral modeling shows that about 0.1% of the 80- by 60-meter area is CO2 ice. This exposed ice was observed a short time after the comet exited local winter; following the increased illumination, the CO2 ice completely disappeared over about 3 weeks. We estimate the mass of the sublimated CO2 ice and the depth of the eroded surface layer. We interpret the presence of CO2 ice as the result of the extreme seasonal changes induced by the rotation and orbit of the comet.

Distribution of phyllosilicates on the surface of Ceres.

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.

Bright carbonate deposits as evidence of aqueous alteration on (1) Ceres.

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.

Exposed water ice on the nucleus of comet 67P/Churyumov-Gerasimenko.

Although water vapour is the main species observed in the coma of comet 67P/Churyumov-Gerasimenko and water is the major constituent of cometary nuclei, limited evidence for exposed water-ice regions on the surface of the nucleus has been found so far. The absence of large regions of exposed water ice seems a common finding on the surfaces of many of the comets observed so far. The nucleus of 67P/Churyumov-Gerasimenko appears to be fairly uniformly coated with dark, dehydrated, refractory and organic-rich material. Here we report the identification at infrared wavelengths of water ice on two debris falls in the Imhotep region of the nucleus. The ice has been exposed on the walls of elevated structures and at the base of the walls. A quantitative derivation of the abundance of ice in these regions indicates the presence of millimetre-sized pure water-ice grains, considerably larger than in all previous observations. Although micrometre-sized water-ice grains are the usual result of vapour recondensation in ice-free layers, the occurrence of millimetre-sized grains of pure ice as observed in the Imhotep debris falls is best explained by grain growth by vapour diffusion in ice-rich layers, or by sintering. As a consequence of these processes, the nucleus can develop an extended and complex coating in which the outer dehydrated crust is superimposed on layers enriched in water ice. The stratigraphy observed on 67P/Churyumov-Gerasimenko is therefore the result of evolutionary processes affecting the uppermost metres of the nucleus and does not necessarily require a global layering to have occurred at the time of the comet's formation.

Ammoniated phyllosilicates with a likely outer Solar System origin on (1) Ceres.

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.

The diurnal cycle of water ice on comet 67P/Churyumov-Gerasimenko.

Observations of cometary nuclei have revealed a very limited amount of surface water ice, which is insufficient to explain the observed water outgassing. This was clearly demonstrated on comet 9P/Tempel 1, where the dust jets (driven by volatiles) were only partially correlated with the exposed ice regions. The observations of 67P/Churyumov-Gerasimenko have revealed that activity has a diurnal variation in intensity arising from changing insolation conditions. It was previously concluded that water vapour was generated in ice-rich subsurface layers with a transport mechanism linked to solar illumination, but that has not hitherto been observed. Periodic condensations of water vapour very close to, or on, the surface were suggested to explain short-lived outbursts seen near sunrise on comet 9P/Tempel 1. Here we report observations of water ice on the surface of comet 67P/Churyumov-Gerasimenko, appearing and disappearing in a cyclic pattern that follows local illumination conditions, providing a source of localized activity. This water cycle appears to be an important process in the evolution of the comet, leading to cyclical modification of the relative abundance of water ice on its surface.

Cometary science. The organic-rich surface of comet 67P/Churyumov-Gerasimenko as seen by VIRTIS/Rosetta.

The VIRTIS (Visible, Infrared and Thermal Imaging Spectrometer) instrument on board the Rosetta spacecraft has provided evidence of carbon-bearing compounds on the nucleus of the comet 67P/Churyumov-Gerasimenko. The very low reflectance of the nucleus (normal albedo of 0.060 ± 0.003 at 0.55 micrometers), the spectral slopes in visible and infrared ranges (5 to 25 and 1.5 to 5% kÅ(-1)), and the broad absorption feature in the 2.9-to-3.6-micrometer range present across the entire illuminated surface are compatible with opaque minerals associated with nonvolatile organic macromolecular materials: a complex mixture of various types of carbon-hydrogen and/or oxygen-hydrogen chemical groups, with little contribution of nitrogen-hydrogen groups. In active areas, the changes in spectral slope and absorption feature width may suggest small amounts of water-ice. However, no ice-rich patches are observed, indicating a generally dehydrated nature for the surface currently illuminated by the Sun.

Increased levels of NF-kappaB inhibitors (IkappaBalpha and IkappaBgamma) in the intestinal mucosa of Crohn's disease patients during infliximab treatment.

The treatment with infliximab is employed successfully in Crohn's disease (CD) but predictors of efficacy are lacking. Activation of the transcription factor NF-kB has been demonstrated in CD and its inhibition is one of the mechanisms by which anti-inflammatory agents exert their effects. We evaluated the production of TNFalpha by peripheral blood mononuclear cells (PBMC) and the levels of NF-kappaB family molecules in the intestinal mucosa during infliximab therapy in 12 patients. TNFalpha was assayed on supernatants of PBMC culture stimulated with PHA or LPS. Immunohistochemistry was also done on intestinal biopsies. In six patients, Western blot analysis of the NF-kappaB subunit Rel-A, and its inhibitors IkappaBalpha and IkappaBgamma was performed on intestinal biopsies and PBMC. The TNFalpha production by LPS stimulated PBMC showed mild changes, while it was increased by PHA-stimulated PBMC after treatment. The number of inflammatory cells in the intestinal mucosa was reduced (p<0.002) by the treatment. In five out of six cases we detected an increase of the IkappaBalpha and IkappaBgamma)inhibitor levels in intestinal biopsies after treatment. An increase of IkappaB inhibitors levels could be one of the mechanisms by which infliximab decreases NF-kappaB activity and exerts its anti-inflammatory effects.

Effects of ibopamine eye drops on intraocular pressure and aqueous humor flow in healthy volunteers and patients with open-angle glaucoma.

PURPOSE: On the basis of intraocular pressure measurements and fluorophotometry we assessed the effects of 2% ibopamine eye drops on aqueous humor production in normal and glaucomatous eyes. METHODS: Thirty subjects (15 healthy volunteers and 15 open-angle glaucoma patients with ocular hypertension) were included in a placebo-controlled study with random assignment of treatment from masked containers. All subjects underwent ophthalmologic examinations and intraocular pressure (IOP) measurements. Fluorophotometry was done in both eyes at baseline (without treatment) and during treatment. Each subject was treated with 1 drop of 2% ibopamine in one eye and 1 drop of placebo in the fellow eye 30 minutes before fluorophotometric scans and every hour after the first instillation (for a total of 4 times). Safety was evaluated by recording adverse events and ocular symptoms and signs. Aqueous humor flow data were analyzed using the paired t-test, comparing ibopamine and placebo-treated eyes. RESULTS: No changes in IOP were detected in normal eyes, whereas glaucomatous eyes showed a mean increase of 4 mmHg (95% CI 3.46-4.51) from baseline. The difference in IOP between healthy eyes and those with glaucoma was significant (p < 0.0001). In normal eyes and patients with glaucoma ibopamine led to a significant increase in aqueous humor flow compared with placebo-treated eyes (p < 0.01). The safety profile of ibopamine was very good. CONCLUSIONS: The results seem to confirm that ibopamine increases aqueous humor production in normal and glaucomatous eyes, raising IOP only in eyes with glaucoma.

Interleukin-6 release in the hepatic blood outflow during normothermic liver ischaemia in humans.

BACKGROUND: Liver surgery techniques have consistently improved and normothermic ischaemia of the liver is considered to be a safe procedure to reduce intraoperative haemorrhage. Hepatic failure, however, remains a significant complication. In liver ischaemia-reperfusion injury, cytokines play a key proinflammatory role. Cytokines may be part of the intercellular signalling that leads to recovery or to failure after major surgery. Moreover, they could be potential predictors of the outcome. Modulation of the pattern of cytokine response in the early postsurgery period could represent a new approach to minimise the impact of these procedures. AIMS: The aim of our study was to analyse the cytokine pattern in the hepatic blood outflow in patients undergoing surgical intervention of partial liver resection with clamping of the hepatic pedicle and liver ischaemia, and to correlate the cytokine behaviour with clinical parameters. PATIENTS: We studied eight patients (mean age 55 years) who underwent surgical intervention of liver resection during vascular exclusion of the hepatic pedicle. Patients were monitored for haemodynamic and haematological parameters during the pre-, infra- and postoperative period. METHODS: IL-I alpha, IL-6, TNF-alpha and IFN-gamma were assayed from peripheral and central vein blood at different times. Blood samples for cytokine assays were also drawn from the supra-hepatic veins after clamping of the porta hepatis. RESULTS: We found a significant increase of the IL-6 levels in the supra-hepatic samples during liver ischaemia, while the trend with IL-1alpha was less clear; IFN-gamma and TNF-alpha were undetectable with the methods used. IL-6 levels appeared to correlate positively with bilirubin and gamma-GT levels and negatively with the degree of acidosis. CONCLUSIONS: Our study confirms that during surgical ischaemic stress there is an increase of IL-6 serum levels more relevant in supra-hepatic vein blood. Cytokines could contribute to modulate the inflammatory response to liver ischaemia.

An update on the medical treatment of Crohn's disease.

Crohn's disease (CD) is a chronic transmural inflammation that may involve any part of the alimentary tract. The affected patients show peculiar metabolic characteristics; they often have a reduced body weight, due to reduction of lipid stores (in spite of lean mass depletion) and an increased utilization of lipids as fuel substrate. An alteration of nutritional status, up to real malnutrition, is common in CD and malnutrition's effects influence the course of disease, acting as independent factors. We will give a description of the main pharmacological approaches in CD management; the first line therapy for CD patients remains the combinations of aminosalicylates, antibiotics, corticosteroids and immunomodulatory agents. The development of new biological agents for the treatment of inflammatory bowel diseases has added to the growing armamentarium of available therapy. We also will explain the importance of enteral nutrition, whose importance goes over the simple amelioration of nutritional status, especially in childhood CD, where it has shown to be as effective as traditional therapy.

A new protein antidenaturant agent, bindarit, reduces secondary phase of adjuvant arthritis in rats.

Bindarit (or 2-[(1-benzyl-indazol-3-yl)methoxy]-2-methyl propionic acid) reduces heat induced denaturation of bovine and rat serum albumin in vitro (EC50 = 8.5 and 65 micrograms/ml, respectively) and inhibits heat induced serum albumin denaturation after in vivo (12.5-25-50 mg/kg po) administration in rats. To assess the relationship between protein denaturation and the development of chronic inflammatory diseases, the drug (0.5 or 0.12% medicated diet) was studied in comparison with indomethacin (1 mg/kg po daily) in rats injected with complete Freund's adjuvant. Bindarit appeared different from aspirin-like drugs, antiinflammatory steroids and immunosuppressants because it does not reduce primary inflammation of arthritic rats and was shown to be completely inactive on cyclo and lipooxygenase activity in vitro and on immune reactions of mice in vivo. Nevertheless, the drug strongly reduced the development of the secondary phase of adjuvant induced arthritis. The most significant effect of bindarit in this phase was a strong inhibition of serum albumin denaturation in arthritic rats. Assessment of both electrophoretic and quantitative changes suggests that the reduction of albumin during inflammation is due, at least in part, to a denaturation of native albumin, which loses its electrophoretic mobility. The involvement of protein denaturation in the production of new antigenic determinants, their pathogenic relevance in the development of adjuvant arthritis and the possibility that protein stabilization by bindarit could be the mechanism of action of the drug are discussed.

Validation of a HPLC method for the determination of bendazac and its main metabolite 5-hydroxybendazac in human plasma.

The purpose of this study was to validate an analytical method for the determination of bendazac and its main metabolite 5-hydroxybendazac in human plasma. The results obtained indicate that the method is reproducible, accurate, precise, sensitive and specific for the measurement of bendazac and 5-hydroxybendazac in the human plasma. Therefore it can be considered suitable for experimental purposes, routine application for drug monitoring and regulatory requirements.

Effects of intraocular dapiprazole in the rabbit eye.

Dapiprazole produces miosis by blocking the alpha 1 receptors in the radial muscle of the iris; its intraocular effect has not yet been investigated. In this preliminary experimental animal study, we investigated the intracameral use of 0.2 ml of 0.005%, 0.0075%, 0.01%, and 0.05% dapiprazole to reverse mydriasis by 10% phenylephrine plus 0.5% tropicamide. With the 0.05% dapiprazole concentration, the values (mean +/- S.E.) of pupillary diameter were as follows: prior to the experiment, 5.3 +/- 0.31 mm; after mydriatics, 8.7 +/- 0.22 mm; after intraocular dapiprazole, 5.6 mm +/- 0.29. The results showed a dose-related miotic effect of dapiprazole. No difference in the toxicity parameters (inflammatory score, corneal thickness, endothelial cell counting, aqueous humor protein concentration, and intraocular pressure) was found between dapiprazole-treated eyes and saline-solution-treated eyes. Intraocular 0.01% and 0.05% dapiprazole is an effective miotic agent that may be helpful during surgery when the reversal of sympathomimetic mydriasis is needed.

Effects of benzydamine eye drops on the rabbit's eye reaction to surgical, physical, and chemical stimuli.

The effects of benzydamine eye drops on the ocular reaction to different irritating stimuli in rabbits are reported. Benzydamine at the concentration of 0.1% reduces inflammatory tissue changes induced by AgNO3 burning of the cornea and inhibits the blood-aqueous barrier breakdown due to peripheral iridectomy or laser irradiation of the iris. Benzydamine reduces the aqueous PGE2 concentration to a similar extent as a 0.5% commercially available eye drop formulation of piroxicam. This result is in contrast with previous in vitro results demonstrating that benzydamine is devoid of any effects on PG synthesis. The possibility that PGE2 reduction is an indirect effect due to other biochemical activities of benzydamine is discussed. In the normal eye benzydamine manifests a local anaesthetic effect which is not accompanied by irritative changes in the anterior segment of the eye, changes in the intraocular pressure or pupillary size. It is suggested that in the clinical use of benzydamine eye drops the local anaesthetic activity may contribute to reducing both the neurogenic component of ocular inflammation and acute pain following injuries to the eye.