Immune enhancing effects of dehydroepiandrosterone and dehydroepiandrosterone sulphate and the role of steroid sulphatase

Steroid hormones, such as glucocorticoids (GC), influence immune and inflammatory responses through their suppressive actions. Recent evidence suggests that another steroid hormone, dehydroepiandrosterone (DHEA), provides an immunostimulatory influence opposing the effect of GC. DHEA circulates in its inactive sulphated form, DHEAS, requiring conversion to DHEA by a steroid sulphatase (SS) enzyme for biological activity. Therefore, inhibition of SS activity may affect immune responses, allowing endogenous GC effects to predominate. We have shown that administration of DHEA and DHEAS in contact sensitization (CS) augments ear swelling by 39 and 46% respectively (P < 0.001). DHEAS at doses of 0.5, 5 and 50 mg/kg reverses the inhibitory effect of corticosterone (5 mg/kg) (P < 0.01). In CS, CT2251 (SS inhibitor) at 10 and 0.1 mg/kg inhibited ear swelling by 61 and 38% (P < 0.05) respectively. In addition, it inhibited DHEAS-augmented responses by 49 and 35% respectively (P < 0.05), with no effect on DHEA-augmented responses. DHEAS reversed CT2251 inhibition of the CS response with complete reversal at 50 mg/kg (P < 0.05). DHEAS and CT2251 appear to affect cellular infiltration into the ear, since DHEAS increased the number of lymphocytes by 63.8% and macrophages by 107% (P < 0.001), whereas CT2251 at 0.1 mg/kg decreased the number of lymphocytes by 65% (P < 0.001) and macrophages by 80% (P < 0.001). DHEAS, CT2251 and dexamethasone had no effect on oedema in the ear. From our data we have shown that steroid hormones, such as DHEA, have the potential to act as immunostimulatory factors in vivo. Inhibiting the conversion of DHEAS to DHEA by SS enzyme leads to an anti-inflammatory effect.     

Signal processing for hyperspectral image exploitation

Electro-optical remote sensing involves the acquisition of information about an object or scene without coming into physical contact with it. This is achieved by exploiting the fact that the materials comprising the various objects in a scene reflect, absorb, and emit electromagnetic radiation in ways characteristic of their molecular composition and shape. If the radiation arriving at the sensor is measured at each wavelength over a sufficiently broad spectral band, the resulting spectral signature, or simply spectrum, can be used (in principle) to uniquely characterize and identify any given material. An important function of hyperspectral signal processing is to eliminate the redundancy in the spectral and spatial sample data while preserving the high-quality features needed for detection, discrimination, and classification. This dimensionality reduction is implemented in a scene-dependent (adaptive) manner and may be implemented as a distinct step in the processing or as an integral part of the overall algorithm. The most widely used algorithm for dimensionality reduction is principal component analysis (PCA) or, equivalently, Karhunen-Loeve transformation     

Buckling behavior of a central cracked thin plate under tension

The buckling characteristics of cracked plates subject to uniaxial tensile loads are analysed by the aid of the finite element method. Owing to the fact that crack buckling behavior is affected by the in-plane stress distribution around a crack, to get more accurate results, pre-buckling in-plane stress fields are analysed by the finite element method. For the critical loads calculation, the finite element approach adopted is based on Von Karman's linearize theory for buckling of plates subjected to pre-buckling state of plane stress. Several singular elements based on the Willian series are used in this plate bending approach. In this study, the effect of crack length, the effect of boundary condition, the effect of Poison's ratio and the effect of biaxial force on critical loads are analysed and discussed. Furthermore, the effect of initial imperfection is also discussed. There is a good agreement between other researcher's work and present results.     

Manganese dioxide electrode—IV. Chemical and electrochemical reduction of an electrolytic γ-MnO2

The chemical or electrochemical reduction of γ-MnO₂ proceeds via a single phase over the complete range MnO₂MnO_1.5. The end member MnO_1.5 has been named δMnOOH to distinguish it clearly from groutite. If the de Wolff model for γMnO₂ is accepted then δMnOOH is an intergrowth structure of groutite with microdomains of manganite. The oxyhydroxide is metastable in the region MnO_1.75MnO_1.5 slowly precipitating γMnOOH as a separate phase in aqueous solutions probably by a dissolution—precipitation mechanism.The filling of the lattice with electrons and protons appears to proceed differently in the ranges MnO₂MnO_1.75 and MnO_1.75MnO_1.5. Two ways in which this might come about are proposed. Evidence from Jahn—Teller distortion favours the explanation that in the first half of reduction an electron entering the structure is delocalised between two adjacent Mn⁴⁺ ions: in the second half an added electron displaces a shared electron and the two electrons are associated with individual cations forming Mn³⁺ ions.     

Co-witness information can have immediate effects on eyewitness memory reports

When questioning a reluctant witness, investigators sometimes encourage the witness by providing information about what other witnesses have said. Three experiments were conducted to test the combined effects of such co-witness information and suggestive questioning on the accuracy of eyewitness memory reports. Experiment 1 was analogous to the experience of a witness who receives information from an interviewer or questioner about what other witnesses have already said, whereas Experiments 2 and 3 simulated the situation in which a witness receives information directly from a co-witness. In all three experiments, when participants received incorrect information about a co-witness's response, they were significantly more likely to give that incorrect response than if they received no co-witness information. This effect persevered in a delayed memory test 48 h after the initial questioning session in Experiment 3. Accuracy rates were lowest of all when incorrect co-witness information was paired with questioning that suggested an incorrect response. These results have implications not only for the immediate effects on the accuracy of witnesses' memory reports, but also for the impact that even one such inaccurate report can have on the manner in which a case is investigated by the police or other authorities.     

N‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl] phthalimide: 2. Detailed study of the monomer cure and properties of the resulting polymer

A detailed study is presented of the high‐temperature cure of the difunctional monomer N‐(2‐biphenylenyl)‐4‐[2′‐phenylethynyl]phthalimide (BPP) and the thermal properties of the resulting homopolymer. Although the phenylethynyl groups are consumed within 1 h at 370 °C, other reactions continue well after this, leading to a cured polymer whose glass transition temperature (T_g) is highly dependent on cure time and temperature. A T_g of 450 °C is achieved after a 16 h cure at 400 °C. Use of chemometrics to analyse the infrared spectra of curing BPP provides evidence for changes in the aromatic moieties during cure, perhaps indicative of co‐reaction between the biphenylene and phenylethynyl groups; however, other processes also contribute to the overall complex cure mechanism. Despite the high T_g values, BPP homopolymer exhibits unacceptably poor thermo‐oxidative stability at 370 °C, showing a weight loss of about 50 % after 100 h ageing. This is perhaps a result of formation of degradatively unstable crosslink structures during elevated‐temperature cure. Copyright © 2004 Society of Chemical Industry     

Clustering problems in optimization models

We discuss a variety of clustering problems arising in combinatorial applications and in classifying objects into homogenous groups. For each problem we discuss solution strategies that work well in practice. We also discuss the importance of careful modelling in clustering problems.Part of this work was carried out while the author was visiting the IOE Department, University of Michigan on a CNR fellowship. Author for correspondence     

A randomized controlled trial of fluoxetine and cognitive behavioral therapy for bulimia nervosa: short-term outcome

This study compared and combined fluoxetine and individual cognitive behavioral therapy in the treatment of bulimia nervosa. Participants were 76 women who sought treatment at the Eating Disorders Program of the Toronto Hospital and who met DSM-III-R criteria for bulimia nervosa. Subjects were randomly assigned to receive fluoxetine alone, cognitive behavior therapy alone, or the two in combination and were treated over 16 weeks. Short-term outcome revealed that all three treatment conditions were associated with clinical improvement across a wide range of parameters. The combination of pharmacotherapy and psychotherapy was superior to pharmacotherapy alone on specific parameters and there was no statistically significant advantage to the combination over psychotherapy alone. Limitations to the study include the absence of a placebo pill group and a waiting list control group as well as a substantial dropout rate across all three treatment conditions.     

Effects of tapering doses of oral prednisone on viral load among HIV-infected patients with unexplained weight loss

In an exploratory study of virologic and immunomodulatory effects of corticosteroid therapy for wasting syndrome, four HIV-infected adults with recent unexplained weight loss were given tapering doses of prednisone over a 2-month period. Serum neopterin and TNF receptor II levels decreased from baseline after 7 days. An antiretroviral effect was observed initially, peaking on days 14-21 (mean change in HIV-1 branched chain DNA assay on day 21 of -0.52 log10; mean change, from baseline to nadir for each individual, of -0.63 log10); subsequent bDNA levels returned toward baseline as prednisone was tapered. No patient lost weight and there was a mean weight gain of 3.5 kg. Anecdotal reports of corticosteroid benefits in the wasting syndrome may result in part from decreased T cell activation leading to decreased HIV replication, an effect that may be self-limited or that may occur only at higher prednisone doses. Studies involving more targeted immunomodulatory agents for wasting syndrome are warranted.