The Role of Glucocorticoid Receptor in the Pathophysiology of Pituitary Corticotroph Adenomas

Adrenocorticotropic Hormone (ACTH)-secreting pituitary adenomas are rare tumors characterized by autonomous ACTH secretion with a consequent increase in circulating cortisol levels. The resulting clinical picture is called Cushing’s disease (CD), a severe condition burdened with high morbidity and mortality. Apart from increased cortisol levels, CD patients exhibit a partial resistance to the negative glucocorticoid (GC) feedback, which is of paramount clinical utility, as the lack of suppression after dexamethasone administration is one of the mainstays for the differential diagnosis of CD. Since the glucocorticoid receptor (GR) is the main regulator of negative feedback of the hypothalamic–pituitary–adrenal axis in normal conditions, its implication in the pathophysiology of ACTH-secreting pituitary tumors is highly plausible. In this paper, we review GR function and structure and the mechanisms of GC resistance in ACTH-secreting pituitary tumors and assess the effects of the available medical therapies targeting GR on tumor growth.     

Structural evolution and hydrogen sulfide sensing properties of NiTiO3-TiO2 sol-gel thin films containing Au nanoparticles

Thin films composed of a matrix of titanium and nickel oxides, doped with gold nanoparticles have been prepared with the sol-gel method and annealed at different time/temperature combinations. Structural characterizations demonstrate the crystallization of nickel titanate and of TiO₂-rutile due to nickel capability to promote rutile crystallization over anatase. Optical characterizations show a tunable refractive index of the samples according to the Ti/Ni ratio, and a high amount of residual porosity even after high temperature annealing. Sensor functionality measurements were performed with H₂, CO and H₂S: high sensitivity for hydrogen sulfide detection has been proved, and the cross sensitivity to the other two gases can be tuned by controlling the nickel amount. For high Ni concentrations, the matrix is composed of NiTiO₃ and TiO₂-rutile, and no cross sensitivity is experienced. For lower Ni amounts, TiO₂-anatase starts to crystallize and the films become sensitive to H₂ and CO.     

On current limits of soil moisture retrieval from ERS-SAR data

Assesses the feasibility of retrieving soil moisture content over smooth bare-soil fields using European Remote Sensing synthetic aperture radar (ERS-SAR) data. The roughness conditions considered in this study correspond to those observed in agricultural fields at the time of sowing. Within this context, the retrieval possibilities of a single-parameter ERS-SAR configuration is assessed using appropriately trained neural networks. Three sources of error affecting soil moisture retrieval (inversion, measurement, and model errors) are identified, and their relative influence on retrieval performance is assessed using synthetic datasets as well as a large pan-European database of ground and ERS-1 and ERS-2 measurements. The results from this study indicate that no more than two soil moisture classes can reliably be distinguished using the ERS configuration, even for the restricted roughness range considered.     

Effect of corticosterone on beta-adrenoceptor density in rat skeletal muscle

Corticosteroid hormones increase the density of beta-adrenoceptors in some tissues and may be able to prevent the anabolic effects of beta-agonists from becoming attenuated. The aim of this study was to find a suitable dose of corticosterone that would up-regulate beta2-adrenoceptors in skeletal muscle without arresting the animal's growth. Male rats were given five daily injections of corticosterone at 0, 6.25, 12.5, 25, or 50 mg/kg. The animals were far more sensitive to the catabolic effects of this steroid than female rats used in a previous study. There was no change in food intake, liver, heart, or soleus muscle mass, but corticosterone caused a dose-related decrease in weight gain, carcass weight, omental fat pad weight, and gastrocnemius/plantaris muscle mass (P < .01). From a regression of muscle mass against dose, we calculated that 4.4 mg x kg(-1) x d(-1) would be the largest dose of corticosterone that a male rat could tolerate without any catabolic effect in skeletal muscle. Corticosterone failed to increase beta-adrenoceptor density at any of the doses tested. We conclude that corticosterone treatment is unlikely to be effective at enhancing the growth response of male rats to beta-agonists.     

PtSi Schottky-barrier focal plane arrays for multispectral imagingin ultraviolet, visible, and infrared spectral bands

PtSi Schottky-barrier detectors, which are conventionally used in the back-illumination mode for thermal imaging in the 3-5-μm infrared (IR) spectral band, are shown to exhibit excellent photoresponse in the near-ultraviolet and visible regions when operated in the front-illumination mode. For devices without antireflection coatings, external quantum efficiency in excess of 60% has been obtained for wavelengths between 400 and 800 nm. The efficiency decreases below 400 nm but is still about 35% at 290 nm. High-quality imaging has been demonstrated in both the visible and 3-5-μm spectral bands for front-illuminated 160×244-element PtSi focal plane arrays integrated with monolithic CCD readout circuitry     

Influence of reduced glutathione infusion on glucose metabolism in patients with non-insulin-dependent diabetes mellitus

To evaluate the relationship between oxidative stress and glucose metabolism, insulin sensitivity and intraerythrocytic reduced glutathione (GSH)/oxidized glutathione (GSSG) ratio were measured in 10 non-insulin-dependent diabetes mellitus (NIDDM) patients and 10 healthy subjects before and after the intravenous administration of GSH. In particular, after baseline insulin sensitivity was assessed by a 2-hour euglycemic hyperinsulinemic clamp, either glutathione (1.35 g x m2 x min(-1)) or placebo (saline) were infused over a period of 1 hour. The same protocol was repeated at a 1-week interval, in cross-over, according to a randomized, single-blind design. In healthy subjects, baseline intraerythrocytic GSH/GSSG ratio (P < .0005) and total glucose uptake (P < .005) were significantly higher than in NIDDM patients. In the same subjects, GSH infusion significantly increased total glucose uptake (from 37.1 +/- 6.7 micromol kg(-1) x min(-1) to 39.5 +/- 7.7 micromol x kg(-1) x min(-1), P < .05), whereas saline infusion was completely ineffective. In addition, the mean intraerythrocytic GSH/GSSG ratio significantly increased after GSH infusion (from 21.0 +/- 0.9 to 24.7 +/- 1.3, P < .05). Similar findings were found in diabetic patients, in whom GSH infusion significantly increased both total glucose uptake (from 25.3 +/- 9.0 micromol x kg(-1) x min(-1) to 31.4 +/- 10.0 micromol x kg(-1) x min(-1), P < .001) and intraerythrocytic GSH/GSSG ratio (from 14.8 +/- 4.1 to 21.7 +/- 6.7, P < .01). Pooling diabetic patients and controls, significant correlations were found between intraerythrocytic GSH/GSSG ratio and total glucose uptake (r = .425, P < .05), as well as between increments of the same variables after GSH infusion (r = .518, P < .05). In conclusion, our data support the hypothesis that abnormal intracellular GSH redox status plays an important role in reducing insulin sensitivity in NIDDM patients. Accordingly, intravenous GSH infusion significantly increased both intraerythrocytic GSH/GSSG ratio and total glucose uptake in the same patients.     

Formation of a Quasi‐Free‐Standing Single Layer of Graphene and Hexagonal Boron Nitride on Pt(111) by a Single Molecular Precursor

It is shown that on Pt(111) it is possible to prepare hexagonal boron nitride (h‐BN) and graphene (G) in‐plane heterojunctions from a single molecular precursor, by thermal decomposition of dimethylamine borane (DMAB). Photoemission, near‐edge X‐ray absorption spectroscopy, low energy electron microscopy, and temperature programmed desorption measurements indicate that the layer fully covers the Pt(111) surface. Evidence of in‐plane layer continuity and weak interaction with Pt substrate has been established. The findings demonstrate that dehydrogenation and pyrolitic decomposition of DMAB is an efficient and easy method for obtaining a continuous almost freestanding layer mostly made of G, h‐BN with only a low percentage (<3%) of impurities (B and N‐doped G domains or C‐doped h‐BN or boron carbonitride, BCN at the boundaries) in the same 2D sheet on a metal substrate, such as Pt(111), paving the way for the advancement of next‐generation G‐like‐based electronics and novel spintronic devices.     

Physical and thermal characterization of polylactic acid meltblown nonwovens

A series of polylactic acid (PLA) nonwovens were prepared by the melt blowing process using micro and nano dies. The nonwovens were characterized for structural, thermal, and mechanical properties. These properties varied with the type of die, airflow, and die to collector distance (DCD). The mean pore size for PLA microfiber ranged between 1.82 and 10.48 micrometers, and nanofiber nonwovens ranged between 452 and 818 nanometers. The tensile modulus and strength of PLA nonwovens increased with airflow at a given DCD, but decreased with increased DCD for a given airflow. Thermograms from calorimetry showed microfiber mats had a larger composition of beta‐form crystals than the nanofiber mats. The results showed that a wide range of nonwovens can easily be generated with properties tailored to the specific application. © 2014 Wiley Periodicals, Inc. J. Appl. Polym. Sci. 2014 , 131, 40593.     

65 nm CMOS SSB mixer for UWB synthesiser

The present work addresses the design of a 65 nm CMOS wide-band single-sideband mixer for UWB synthesiser. The circuit has been designed inductorless and with few capacitors, in order to save silicon area and, at the same time, to get a mixer independent of the adopted frequency plan and synthesiser architecture. Particular attention has been paid to reducing the spurs as much as possible. In order to address a realistic investigation, the design has accounted also for the corner cases and the possible impairments in the input signals. A comparison with the state-of-the-art of the SSB mixers shows the low power consumption of the present work.