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Interferon (IFN)-α2 is an extensively therapeutically used pro-inflammatory cytokine. Though its efficacy in controlling viral replication and tumor cells proliferation, administration of IFN-α2 is often associated with the development of central side effects. Magnetic resonance spectroscopy studies have demonstrated that IFN-α2 administration affects brain metabolism, however the exact nature of this effect is not completely known. We hypothesized that IFN-α2 can affect metabolic activity of human neuron-like SH-SY5Y cells which possess many characteristics of neurons and represent one of the most used models for studying mechanisms involved in neurotoxicity or neuroprotection. To test our hypothesis we have characterized the metabolic signature of live SH-SY5Y, and their conditioned media, after 24 and 72 h of exposure to vehicle or IFN-α2 (100 ng/ml) by using High Resolution-Magic Angle Spinning (HR-MAS) Nuclear Magnetic Resonance (NMR) spectroscopy. Our results revealed that 1) the use of HR-MAS NMR is ideally suitable for the characterization of the metabolic profile of live cells and their conditioned media without extraction procedures; and 2) a 72 h exposure to IFN-α2 increases the level of metabolites involved in maintaining energetic (including creatine and lactate) and osmotic (such as myo-inositol, scyllo-inositol, taurine and glycerophosphorylcholine) balances in neuron-like cells and of metabolic waste products (namely lactate, ethanol and acetate), glycine and glutamine in their growth media. These results may contribute to gain more knowledge about the IFN-α2 induced effect on the brain and support the interpretation of magnetic resonance spectroscopy studies performed in humans.

27th European Photovoltaic Solar Energy Conference and Exhibition; 2907-2910, Polymer solar cells have evolved as a promising cost-effective alternative to silicon-based ones. However, low efficiency of these plastic devices limits their feasibility for commercial use. The efficiencies of polymer photovoltaic cells got a major boost with the introduction of the bulk heterojunction (BHJ) configuration consisting of an interpenetrating network of electron donor and acceptor materials. Recently, benzodithiophene based polymers has been used as electron donors in polymer solar cells showing very promising properties such as an increasing charge transport and a red shift of the absorption spectra. In this work the synthesis, the spectroscopic and photovoltaic characterization of a copolymer based on (octylsulfanyl)bithiophene and benzo[1,2-b:4,5-b’]dithiophene units and a polymer based on (butylsulfanyl)bithiophene unit are reported. BHJ solar cells using these polymers as donor materials blended with [70]PCBM as acceptor were prepared and investigated. The geometry of the device is: glass/ITO/PEDOT:PSS/blend/Ca/Al. The electrical performances of the cells were compared in order to study the influence of the benzodithiophene unit on the polymer backbone. The power conversion efficiency of the best realized polymer solar cell is 2.3% under 100 mW/cm2 AM 1.5G illumination.

We report a 1H and 13C HR-MAS NMR study of normal and diseased brain regions of rats bearing C6 gliomas implanted. The detection of selectively enriched metabolites through ex vivo HR-MAS spectroscopy and the correlations with the expression of the genes involved in the glycolytic metabolism are the aims of this work. C6 gliomas were induced in Wistar rats and tumour growth was evaluated in vivo using T1 and T2 weighted MRI. Three weeks after C6 implantation, rats were infused with [1-13C] glucose and then cerebral metabolism was arrested. The fixed brain was removed from the skull and five biopsies were taken from different brain regions (fig.1). The proton spectra show the increase in lactate and mobile lipids in the tumour biopsies and the 13C spectra present a significant increase of (3-13C) lactate and decrease of (4-13C) glutamate and (4-13C) glutamine, revealing a marked increase in glycolytic metabolism in the tumour. Then, we investigated the individual expression of specific genes coding for some enzymes involved in the glycolytic pathway, to improve our understanding of the genetic basis of the metabolic profile observed by 13C HR-MAS. For example, the study of the genes expression encoding for Lactate Dehydrogenase (LDH) enzyme shows the increased expression and the activity of the gene in region 3 and 4, in agreement with the HR-MAS spectra. The Lactate Dehydrogenase is an enzyme that catalyzes the conversion of lactate to pyruvate. This is an important step in energy production in cells. Increase of LDH indicates cellular death or leakage of the enzyme from the cell. Indeed, 13C HR-MAS reveals important metabolic changes in different regions of the brain of rats bearing C6 gliomas, previously not detectable by in vivo or in vitro 13C NMR. The glycolysis genes studied in this work improved our understanding of the metabolic profile observed by 13C HR-MAS spectroscopy in different brain regions of rats bearing C6 gliomas.

23rd European Photovoltaic Solar Energy Conference and Exhibition, 1-5 September 2008, Valencia, Spain; 651-654, Polymer solar cells have evolved as a promising cost-effective alternative to silicon-based solar cells. However, low efficiency of these plastic solar cells limits their feasibility for commercial use. The efficiencies of polymer photovoltaic cells got a major boost with the introduction of the bulk heterojunction (BHJ) concept consisting of an interpenetrating network of electron donor and acceptor materials. In this work we describe the preparation of BHJ organic solar cells using blend films of poly[4,4’-bis(alkylsulfanyl)- 2,2’-bithiophene] (P3ST) and 1-(3-methoxycarbonyl)-propyl-1-phenyl-(6,6)C61 (PCBM). Photovoltaic cells were prepared with a layer sandwiched between electrodes with different work functions. The electrical performance of the devices were compared with the corresponding one prepared using a blend of commercial poly(3-hexylthiophene) (P3HT) and PCBM. The quantum efficiency of the device fabricated with P3ST/PCBM blend shows a better response in the visible region compared to the one with P3HT/PCBM.

The replacement of the 12C present in cerebral metabolites by 13C derived from appropriate 13C enriched precursors, as detected by 13C NMR, has allowed the determination of the cerebral tricarboxylic acid and glutamine cycle fluxes. However, the 13C NMR method is relatively insensitive and requires significantly long acquisitions, a circumstance limiting the time resolution of the method. Up to now, only fluxes slower than the tricarboxylic acid cycle flux have been determined after fitting the 13C turnover curves to appropriate models of cerebral metabolism. To overcome this limitation we proposed earlier the investigation of the 1H-2H exchange of specific metabolite protons from 13C isotopomers, a process depicting faster kinetics and thus potentially able to investigate faster reaction rates. However, the High Resolution 13C NMR approach we proposed earlier, requires the use of relatively large amounts of brain samples for the preparation of extracts. More recently, it has become possible to obtain high resolution 13C and 1H NMR spectra directly from the tissue biopsies avoiding extract preparation, by using High Resolution-Magic Angle Spinning (HR-MAS) Spectroscopy. Here, we report on the use of 1D and 2D 2H, 1H-2H and 1H-13C HR MAS methodologies to investigate quantitatively 1H-2H turnover in small (< 10 mg), intact and unprocessed, biopsy samples prepared from the brain of deuterated rats.

Colorectal cancer is the fourth most common cancer with high morbidity and mortality. Here, we report a spectroscopic study of healtny and neoplastic colon tissues in combination with multivariate analysis with the aim to find metabolic markers differentiating colon tumors. The characterization of the metabolic profiles was performed through High Resolution Magic-Angle Spinning (HR-MAS) NMR spectroscopy on biopsies or chirurgical samples of human colorectal tissues. Principal Component Analysis (PCA) was carried out as explorative analysis in order to obtain an overview on the whole data set without forcing any model and to extract relevant information. Partial Least Squares-Discriminant Analysis (PLS-DA) was used to build a classification model able to separate the classes of healthy, macroscopically normal and neoplastic human colon tissues based on their ex vivo HR-MAS NMR spectra. Samples of 23 patients, 14 with colon cancer, and 9 healthy were evaluated. From all the patients affected by colon cancer, macroscopically normal colon specimens at least 15 cm from the adenocarcinoma were also collected. NMR spectra of samples were acquired using a Bruker Avance400 NMR spectrometer (4 kHz spinning, 4° C). PCA and PLS-DA analyse were carried out using PLS-Toolbox 4,1 for MATLAB. 1D and 2D HR-MAS NMR experiments provide a complete and unambiguous identification of the metabolic pattern characterizing the examined tissues. The NMR spectra of neoplastic and macroscopically normal colon tissues present different metabolic profiles with respect to thse of the healthy ones. Furthermore, the NMR spectra display variations in the metabolic profile for neoplastic tissues with different histological diagnosis, and also for those classified identical from the histological analyses. This findings indicates that the family of colon carcinoma is characterized by metabolic heterogeneity also within the same subclass of tumours. The statistical multivariate approach applied to HR-MAS NMR spectra permits to find metabolic markers of the healthy and the neoplastic state of colon tis¬sues, and to correctly classify the samples. The combination of spectroscopic data with statistical analyses offers a useful tool to better understand some molecular aspects of colon tumour biochemistry, as well as to identify tumoral markers (taurine, myo-inositol, choline containing compounds, carboxylic acids and lipids), and could represent the molecular basis for an accurate and non invasive clinical applications if in vivo NMR.

Cerebral tissue heterogeneity plays a fundamental role in phystological and pathological conditions. Previous 13C NMR approaches in rodents allowed the in vivo investigation of sufficiently large tissue regions (approaching the size of the whole brain) or in vitro analysis of extracts derived from abundant tissue biopsies (> 1g). These limitations precluded a detailed 13C NMR analysis of regional cerebral metabolism in smaller regions. Recently, High Resolution Magic Angle Spinning (HR-MAS) approaches have allowed to obtain high quality 13C spectra from small tissue biopsies (ca. 10 mg), opening the way to investigate cerebral tissue heterogeneity within the microliter range. Here we report, for the first time to our knowledge, a 13C HR MAS study of normal and diseased brain regions of rats bearing implanted C6 gliomas. C6 gliomas were induced Wistar rats (180-250 g) by stereotaxic injection of C6 cells in the left caudate nucleus. Tumor growth was evaluated in vivo using T, and T2 weighted MRI (Bruker Pharmascan 7 Tesla). Three weeks after implantation, rats were anesthetized with isoflurane and infused with [l-13C] glucose (8 mol/100g, 45 minutes). After the infusion cerebral metabolism was arrested using a high-power focused microwaves (5 kW), the fixed brain removed from the skull and five biopsies taken from different brain regions; 1: contralateral brain, 2: normal brain region limiting to the edema limits of the tumor, 3: peripheral (vascularised) tumor zone, 4: tumor central (necrotic) zone and 5; ipsilateral normal hemisphere. Biopsies were analyzed by 1H and 13C HR-MAS (4 KHz spinnng, 4° C, 11.7 Tesla Bruker AVANCE500 WB spectrometer). Figure 2 illustrates the different 1H HR-MAS spectra obtained. It is remarkable the increase in lactate and mobile lipids in the tumour biopsies (regions 3 and 4). Figure 3 shows the 13C labelling patterns obtained by 13C HR-MAS of the same tissue regions. In the tumor biopsies, it is possible to detect significant increases of (3-13C) lactate and decreases of (4-13C) glutamate and (4-13C) glutamine, revealing a marked increase in glycolitic metabolism in the tumor. We quantified these changes determining 1H HR-MAS (LC model analysis) the (3-13C) lactate concentration and used this to quantify the remaining 13C HR-MAS observable metabolites. Ex vivo 13C HR-MAS spectroscopy reveals important metabolic heterogeneity changes in different regions of the brain of rats bearing C6 gliomas, previously not detectabteble in vivo or in vitro 13CNMR.