Raman and UV–vis spectroscopic study of polyaniline membranes containing a bulky cationic additive

Electrically conducting soluble polyaniline (PANI), containing different amounts of a bulky lipophilic cationic additive, tridodecylmethylammonium chloride (TDMACl), was studied by Raman (λ_exc=780 nm) and UV–vis spectroscopy. PANI was made simultaneously electrically conducting and soluble with bis[4-(1,1,3,3-tetramethylbutyl)phenyl]phosphoric acid in dichloromethane. The PANI membranes were prepared by drop casting on glassy carbon or ITO substrates. Raman and UV–vis measurements were carried out in a 0.1 M CaCl₂ solution at potentials between 400 and ?600 mV (vs. SCE) at pH 6, or alternatively at the open circuit potential at pH 10. The results of Raman, UV–vis and cyclic voltammetric measurements confirm that the incorporation of TDMACl into the PANI membrane facilitates the oxidation and reduction of PANI.     

Bioactive glass as bone-graft substitute for posterior spinal fusion in rabbit

Bioactive glass S53P4 and autogenous bone were studied as bone graft materials for spinal fusion in a rabbit model. Sixteen rabbits underwent surgery by a dorsal approach. A bioactive glass, a combination of bioactive glass and autogenous bone (70/30 vol%), and autogenous bone were implanted at two thoracolumbar vertebraes for 4 and 12 weeks. The volume, consolidation to vertebrae, and fusion of the graft material were evaluated with plain-film radiology, computed tomography (CT) and bone-mineral density measurements, and compared with histomorphometrical measurements. Radiological consolidation by CT of bone graft to underlying vertebrae at 12 weeks was observable in all groups. This was histologically confirmed as bone was growing from the vertebrae into the graft material. Radiologic fusion of vertebraes was, at 12 weeks, observable in all groups in 50--75% of the cases. The radiologic fusion seen at the CT scans could, however, not be confirmed by histology in any of the three groups. Significant differences for graft material and observation period with the use of bone-mineral density measurements (Hounsfield units) were also observable, with the highest measured values for the bioactive glass group and the lowest for the autogenous bone group. The results indicate that bioactive glass have potential as bone-graft material in spinal fusion. The reliability of radiologic evaluation methods in spinal surgery using bone substitutes is also questioned and discussed.     

Enzymatic detoxification of gluten by germinating wheat proteases: Implications for new treatment of celiac disease

Introduction. Currently the only treatment for celiac disease is a lifelong gluten-free diet. The diet is, however, often burdensome, and thus new treatment options are warranted. We isolated proteases from germinating wheat grain naturally meant for total digestion of wheat storage proteins and investigated whether these enzymes can diminish toxic effects of gluten in vitro and ex vivo.

Methods. Pepsin and trypsin digested (PT) gliadin was pretreated with proteases from germinating wheat, whereafter the degradation was analyzed by HPLC-MS (high-performance liquid chromatography and mass spectroscopy) and sodium dodecyl sulphate polyacrylamide gel electrophoresis. The toxicity of cleaved PT-gliadin products was assessed in Caco-2 epithelial cells, celiac patient-derived T cells, and in human small intestinal mucosal organ culture biopsies.

Results. Proteases from germinating wheat degraded gliadin into small peptide fragments, which, unlike unprocessed PT-gliadin, did not increase epithelial permeability, induce cytoskeletal rearrangement or changes in ZO-1 expression in Caco-2 cells. Pretreated gliadin did not stimulate T cell proliferation in vitro or enhance the production of autoantibodies to culture supernatants and the activation of CD25+ lymphocytes in the organ culture to the same extent as unprocessed PT-gliadin.

Discussion. Germinating wheat enzymes reduce the toxicity of wheat gliadin in vitro and ex vivo. Further studies are justified to develop an alternative therapy for celiac disease.     

Fgf20 governs formation of primary and secondary dermal condensations in developing hair follicles

In hair follicle development, a placode-derived signal is believed to induce formation of the dermal condensation, an essential component of ectodermal organs. However, the identity of this signal is unknown. Furthermore, although induction and patterning of hair follicles are intimately linked, it is not known whether the mesenchymal condensation is necessary for inducing the initial epithelial pattern. Here, we show that fibroblast growth factor 20 (Fgf20) is expressed in hair placodes and is induced by and functions downstream from epithelial ectodysplasin (Eda)/Edar and Wnt/β-Catenin signaling to initiate formation of the underlying dermal condensation. Fgf20 governs formation of primary and secondary dermal condensations in developing hair follicles and subsequent formation of guard, awl, and auchene hairs. Although primary dermal condensations are absent in Fgf20 mutant mice, a regular array of hair placodes is formed, demonstrating that the epithelial patterning process is independent of known histological and molecular markers of underlying mesenchymal patterns during the initial stages of hair follicle development.