Expandable metal stents for the treatment of colonic obstruction: techniques and outcomes

Modulation of CD8(+) T-cell responses specific for an exogenous antigen by epitope variants would be advantageous to develop a novel means of antigen-specific immune regulation. We have analyzed CD8(+) T-cell responses to single amino acid-substituted variants of a peptide corresponding to residues 142-149 (p142-149; LAYFYPEL) of alphas1-casein, a major milk allergen, which is a dominant determinant restricted by H-2Kb. An analog peptide L142I with a substitution of Ile for Leu at the nonanchor N-terminal residue induced more IFN-gamma secretion than p142-149 from specific CD8(+) T cells. Furthermore, L142I could prime CD8(+) T cells more efficiently in vivo, and these L142I-primed cells secreted more IFN-gamma than p142-149-primed CD8(+) T cells upon stimulation with p142-149 in vitro. These findings are mainly explained by the greater ability of L142I to form stable Kb-peptide complexes. These findings indicate that appropriate analog peptides may be useful as efficient inducers of CD8(+) T cells which recognize the parent peptide and secrete IFN-gamma, a potent inhibitor of Th2-dependent events, including IgE production.     

Preparation of the myristoylated and nonmyristoylated form of recombinant recoverin in E. coli cells and comparison of their functional activity]

Numerous data strongly suggest the involvement of cytokines and the matrix metalloproteinase collagenase (MMP-1) in the pathogenesis of periodontitis. Recently, we have demonstrated that, upon culturing under the influence of IL-1 alpha + EGF, a large amount of inactive procollagenase (MMP-1) is stored in the extracellular matrix of periosteal tissue. We now show that this endogenous reservoir of proenzyme can be operative after activation with plasmin and is able to induce a rapid and almost complete breakdown of the collagenous extracellular matrix. The level of collagen degradation following activation showed a strong correlation with the amount of proenzyme that was incorporated in the tissue. The highest level of degradation (70% of the total amount of collagenous proteins) was found with the IL-1 alpha + EGF-treated explants, followed by those treated with IL-1 alpha alone (35%). Explants cultured with EGF or in the absence of cytokines, containing only small amounts of procollagenase, showed little collagen breakdown following plasmin activation (7%). Inhibition of metalloproteinases by EDTA, or blockage of plasmin by PMSF, prevented the degradation in all explants irrespective of the amount of proenzyme present in the tissue. Our findings demonstrate that endogenous proenzyme stored in a native connective tissue matrix can be activated at a later time interval which results in a massive breakdown of the tissue. This study shows a possible pathway of collagenase-induced breakdown without recent de novo synthesis of the enzyme. Such a sequence may be operative in chronic inflammatory diseases, such as periodontitis, where production of procollagenase under the influence of cytokines spans a longer time period, whereas breakdown is often characterized by a cyclic behaviour.     

Image Enhancement of Conventional Transverse-Axial Tomograms

An image processing system for image enhancement of conventional transverse axial tomography (TAT) is described. Conventional TAT means a tomography system in which the X-ray source and X-ray film move in a circular arc about the long axis of the patient, which is a different technique from computerized tomography. In the image processing system described, the original X-ray tomograms are digitized, high-pass filtered, and displayed on a TV monitor. The results of processing several clinical tomograms are shown, and definite improvements in the observed information are noted. The basic technique should be equally applicable to other conventional tomography systems, e.g., linear tomography or hypocycloidal tomography.     

Multiplicity of the steady state in fluidised bed reactors — I.: Steady state considerations

Multiple steady states are known to be possible in many types of chemical reactor due to the non-linear dependence of reaction rate on either temperature or reactant concentration. It is reasoned in this study that multiple steady states can also exist in a gas-solid fluidised bed reactor. The calculations are based on the two-phase theory of fluidisation and on the important assumption that the interstitial phase gas in completely mixed. Both thermal and concentration multiplicites are shown to be possible.     

A model for random sampling and estimation of relative protein abundance in shotgun proteomics

Proteomic analysis of complex protein mixtures using proteolytic digestion and liquid chromatography in combination with tandem mass spectrometry is a standard approach in biological studies. Data-dependent acquisition is used to automatically acquire tandem mass spectra of peptides eluting into the mass spectrometer. In more complicated mixtures, for example, whole cell lysates, data-dependent acquisition incompletely samples among the peptide ions present rather than acquiring tandem mass spectra for all ions available. We analyzed the sampling process and developed a statistical model to accurately predict the level of sampling expected for mixtures of a specific complexity. The model also predicts how many analyses are required for saturated sampling of a complex protein mixture. For a yeast-soluble cell lysate 10 analyses are required to reach a 95% saturation level on protein identifications based on our model. The statistical model also suggests a relationship between the level of sampling observed for a protein and the relative abundance of the protein in the mixture. We demonstrate a linear dynamic range over 2 orders of magnitude by using the number of spectra (spectral sampling) acquired for each protein.