Biochemical properties of protease resistant prion protein PrPsc in natural sheep scrapie

Prions are infectious agents involved in neurodegenerative diseases, such as scrapie in sheep and goats, bovine spongiform encephalopathy (BSE) in cows and Creutzfeldt-Jakob disease (CJD) in humans. These pathogens are characterized by unusual properties, and, in particular, by their strong resistance to common procedures of disinfection used against conventional microorganisms. A major component of highly infectious fractions is a proteinase K-resistant prion protein PrPsc (PrP-res), the normal host prion protein PrPc being sensitive to PK (PrP-sen). We used a biochemical approach to further characterize PrPsc protein in natural sheep scrapie. Western blot analyses using rabbit antiserum that recognized both normal and pathologic sheep prion proteins, were undertaken to study the biochemical behaviour of PrPsc extracted from brains of sheep naturally infected with scrapie after protease digestion and under denaturing conditions. Increasing concentrations of urea (1-7 M) or GdnSCN (0.25-3 M) and different pH from 2 to 11 were tested for their effects on protease resistance of PrPsc. Alkaline pH (pH = 10) and high concentrations of urea (> 3 M) and GdnSCN (> 0.75 M) greatly decreased the protease resistance of the prion protein. Identical experiments carried out on three different sheep from the same flock gave similar results. The biochemical behaviour of PrPsc under denaturing conditions and in the presence of proteinase K could thus provide a biochemical means for further characterization of different natural scrapie isolates.     

Model Based Evaluation of Bridge Decks Using Ground Penetrating Radar

Abstract:   Ground penetrating radar (GPR) has become a viable technology for non-destructive condition assessment of reinforced concrete structures. Interpretation of the radar signal is typically performed through preliminary filtering techniques and interpretation is based on viewing numerous signals in the form of a scan. Although anomalies can be evident in the scanned image, quantification and interpretation of the main issue remain ambiguous. This article presents the ambiguity and common methods of interpretation based on response amplitude and travel time. An integrated medium is developed and used as a forward modeling tool to generate a realistic radar reflection of a reinforced concrete bridge deck with defects. A healthy deck reflection is obtained from a separate model and is combined with an inverse solution to quantifiably estimate unknown subsurface properties such as layer thickness and dielectric constants of subsurface materials evident in the realistic radar trace as well as. The forward modeling tool and associated model based assessment provides an objective computational alternative to the interpretation of scanned images.     

New Polymeric Phase in Low‐Doped Lithium Intercalated Fullerides

Abstract

The low‐doped Li _x C₆₀ compounds (x≤6) were investigated using laboratory X‐ray and synchrotron radiation diffraction, ¹³C NMR and Raman spectroscopy. Li₄C₆₀ shows an unusual 2D polymerisation in which the C₆₀ units are connected both by [2+2] cycloaddition and by single carbon–carbon bonds, a unique feature among the known polymerised fullerene compounds. This picture is fully supported also by static NMR and Raman measurements. The charge transfer to C₆₀ in the polymeric phase was evaluated from the shift of the A_g(2) mode. The depolymerisation process was investigated as well; despite the presence of two different bonds, the polymer‐to‐monomer transition induced by thermal treatments is a single‐step phenomenon.     

Few electron limit of n-type metal oxide semiconductor single electron transistors

We report the electronic transport on n-type silicon single electron transistors (SETs) fabricated in complementary metal oxide semiconductor (CMOS) technology. The n-type metal oxide silicon SETs (n-MOSSETs) are built within a pre-industrial fully depleted silicon on insulator (FDSOI) technology with a silicon thickness down to 10 nm on 200 mm wafers. The nominal channel size of 20 × 20 nm(2) is obtained by employing electron beam lithography for active and gate level patterning. The Coulomb blockade stability diagram is precisely resolved at 4.2 K and it exhibits large addition energies of tens of meV. The confinement of the electrons in the quantum dot has been modeled by using a current spin density functional theory (CS-DFT) method. CMOS technology enables massive production of SETs for ultimate nanoelectronic and quantum variable based devices.     

Contact Problems for Two Elastic Layers Resting on Elastic Half-Plane

This paper is concerned with the continuous and discontinuous contact problem of two elastic layers resting on an elastic semi-infinite plane. The top layer is subjected to a uniform pressure applied over a finite portion of its top surface. It is assumed that the contact between all surfaces is frictionless. The problem is solved using the theory of elasticity, and body forces are taken into account. Separation may occur between the top and the bottom layers or between the bottom layer and the half-plane or between both interfaces. The problem is formulated in terms of singular integral equations obtained from the discontinuous contact positions and is numerically solved by the Gauss-Chebyshev integration method. Furthermore, numerical results for the separations and the loads corresponding to these separations and the stress distribution on the contact interfaces are given in graphical forms.     

Novel HLA-Cw8-restricted T cell epitopes derived from tyrosinase-related protein-2 and gp100 melanoma antigens

The identification of T cell epitopes presented by alternative HLA-B and -C alleles may provide a means to counteract the tumor escape mechanism based on the selection of tumor cells no longer susceptible to HLA-A-restricted T cell recognition. Several T cell clones and lines were obtained from T lymphocytes purified from melanoma-infiltrated or noninfiltrated lymph nodes of a patient who remained disease free 8 yr after surgery. Selected T cells recognized the autologous melanoma as evaluated by direct cytolysis and production of cytokines. These effectors were directed against the tyrosinase-related protein-2 (TRP-2) and gp100 melanoma epitopes restricted by HLA-Cw8. The nonamer and decamer peptides containing the sequence ANDPIFVVL (residues 387-395) of TRP-2 and the octamer, nonamer, and decamer peptides containing the sequence SNDGPTLI (residues 71-78) of gp100 reconstituted the epitope for TRP-2- and gp100-specific T cell lines and clones, respectively. However, only the nonameric form of TRP-2 and the nonameric and octameric forms of gp100 were able to induce peptide-specific T cells recognizing the autologous tumor in an HLA-class I-restricted fashion from PBMC of the melanoma patient studied. Together these data indicate that HLA-Cw8 can restrict the recognition of gp100 and TRP-2 epitopes by CTL, and that such peptides could stimulate a patient's PBL, suggesting that these Ags could have contributed to a systemic immunity against melanoma.     

Dexrazoxane cardioprotection in advanced breast cancer patients undergoing high-dose epirubicin treatment

PURPOSE: We performed a randomized trial to evaluate the cardioprotective effect of dexrazoxane (DEX) in advanced breast cancer patients (ABC) treated with high single-dose epirubicin (EPI). A secondary objective was to determine the role of radioimmunoscintigraphy (RIS) in the assessment of epirubicin cardiotoxicity. PATIENTS AND METHODS: Ninety-five patients with ABC were treated with EPI 160 mg/m2 by i.v. bolus every 3 weeks with or without DEX, 1,000 mg/m2 i.v. Cardiac monitoring included multigated radionuclide (MUGA) scan with determination of resting left ventricular ejection fraction (LVEF), and RIS with 111-Indium antimyosin monoclonal antibodies. RESULTS: The overall response rate was 69% in the EPI arm and 67% in the EPI + DEX arm; median time to response and median time to progression were identical in both arms, being 2 and 8 months, respectively. Median survival was 19 months versus 29 months (p 0.21), respectively. DEX did not appear to contribute to extracardiac EPI toxicity. Congestive heart failure occurred only in the EPI arm (2 instances). LVEF significantly decreased from baseline only in the EPI group. An abnormal tracer uptake at RIS was observed early in both arms, but the increase in heart to lung ratio was much more evident in the control group. CONCLUSIONS: DEX significantly protects against the development of high dose epirubicin cardiotoxicity apparently without evidence of an adverse impact on antitumor activity and non cardiac toxicity. RIS is a very sensitive technique in detecting anthracycline cardiac damage, but its specificity is low and cannot be considered alone a primary test for guiding anthracycline treatment.