Protective effect of interferon-α on the DNA- and RNA-degrading pathway in anti-Fas-antibody induced apoptosis

Aim: Fas membrane-associated polypeptide antigen is a receptor molecule responsible for apoptosis-mediated signals. In animal models of acute viral hepatitis, apoptosis of hepatocytes is mediated by Fas-death receptors; therefore, the aim of this study was to evaluate the effect of interferon (IFN)-alpha on apoptotic markers and nuclease activity against different coding and non-coding single and double stranded RNAs during Fas-induced liver apoptosis. Methods: An in vivo experiment was performed with simultaneous administration of anti-Fas (CD95) antibodies and IFN-alpha, and an in vitro experiment was performed in hepatocyte cultures treated with anti-Fas antibodies and IFN-alpha. Results: Detection of apoptosis using Annexin V-FITC/propidium iodide, Bcl-2 and Bax expression in hepatocyte cultures confirmed the appearance of early apoptotic events and progression toward late apoptosis after anti-Fas antibody treatment. IFN-alpha had a tendency to retard the apoptosis process in Fas-induced apoptosis by increasing the number of viable cells and decreasing the number of cells in late apoptosis, by increasing the percentage of Bcl-2 positive cells, by decreasing the percentage of Bax positive cells, and by decreasing the nuclease activity compared to the anti-Fas antibody treated group. Total DNA and RNA concentration was much reduced in the Fas group and DNA fragmentation assay provided evidence for increased DNA degradation. Enhanced nuclease activity against DNA, rRNA, poly(A), poly(C), poly(U), poly(I:C), and poly(A:U) was manifested in the anti-Fas antibody treated group, except for the inhibitory-bound alkaline RNase. Conclusions: The results demonstrate that the RNA-degrading pathway in Fas-induced apoptosis can accelerate the liberation of the latent enzyme from the inhibitor complex. IFN-alpha prevented enormous, Fas-ligand induced degradation of all the substrates used in this experimental study, most probably due to similarities in the signal transduction pathways. Investigations of death receptor-induced apoptosis may lead to novel treatment combinations for patients with acute or chronic liver diseases.     

Teilzulassung – neue Gestaltungsmöglichkeit ohne praktische Bedeutung?

Ohne Zusammenfassung     

Addendum to "transfer functions and correction factors used in hearing aid evaluation and research".

In an earlier publication, various transformations used in hearing aid research and its application were summarized. As a result of continued interest and requests, additional transfer functions are provided in this addendum.     

Chemically synthesized solid phase oligosaccharide probes for carbohydrate-binding receptors. Interactions of the E-, L- and P-selectins with sialyl-Le(x) and O-sulphated forms linked to biotin or to polyacrylamide

There is a growing interest in chemically defined oligosaccharide reagents for identifying proteins that bind carbohydrates and determining the specificities of carbohydrate-binding proteins. Here, we compare three sets of chemically synthesized commercially available oligosaccharide conjugates as immobilized probes, for the binding signals that they elicit with known carbohydrate-binding receptors of the immune system, the E-, P- and L-selectins. The first set of conjugates is of oligosaccharides linked to biotin via a nine-carbon spacer. The second and third sets are multivalent derivatives in which the oligosaccharides are linked, via a three-carbon spacer to poly[N-(2-hydroxyethyl)acrylamide] (PAA) or to biotinylated PAA with an average of 20% substitution of the hydroxyethyl-amide groups by carbohydrate. The conjugates were immobilized on streptavidin-coated microwells if biotinylated, otherwise by drying in uncoated wells. The most robust binding curves, overall, were with the biotinylated PAA derivatives of the ligands immobilized on streptavidin wells. These reagents have permitted a reevaluation of selectin binding signals elicited by sialyl-Lewis(x) (SLe(x)) analogues having sulphate at position 6 of the galactose (6'SuSLe(x)) or of the N-acetylglucosamine (6SuSLe(x)). The results clarify the role of 6SuSLe(x), rather then 6'SuSLe(x), as a ligand for the selectins.     

Plasma protein adsorption pattern on characterized ceramic biomaterials.

The protein/biomaterial interactions of three biomaterials used in hard tissue surgery were studied in vitro. A dynamic flow system and two-dimensional polyacrylamide gel electrophoresis (2D-PAGE) were used to investigate the adsorption of proteins from diluted human plasma on hydroxyapatite, alumina and zirconia, with regard to total protein binding capacity, relative binding capacity for specific proteins and flow-through and desorption patterns. The ceramics were characterized regarding physicochemical properties; namely, chemical composition by elementary analyses and specific surface, pore volume and pore size distribution using the BET-method and Hg-porosimetry. The materials were found to adsorb a surprisingly low amount of plasma proteins, leaving more than 70% of the surface free. The cellular response will therefore be highly affected by the physico-chemical properties of the material, in contrast to a surface fully covered with proteins. Regarding the adsorption of proteins, most proteins exhibited similar flow-through patterns on the three adsorbents. The exceptions with different flow-through patterns were apolipoprotein D (Apo D), apolipoprotein J (Apo J), complement factor C1s (C1s), complement factor C3 (C3), ceruloplasmin, fibrinogen, alpha1 B glycoprotein and alpha2 HS glycoprotein and serum retinal-binding protein (SRBP). The role of these proteins on acceptance or rejection of implants has to be investigated.     

Biofeedback as a supportive method in weaning long-term ventilated critically ill patients

Weaning a patient from mechanical ventilation is occasionally a difficult process complicated by the patient's emotional state. Anxiety, agitation, depression and other emotional disturbances can start a vicious circle between fear of losing breath and dyspnea that impairs the process of withdrawing ventilatory support. A biocybernetic loop model is suggested that integrates psychological variables (e.g., capacity of self-control, self-confidence, sense of self-efficacy) as important factors for a successful weaning. The paradigm of biofeedback is regarded as a suited approach to strengthen these psychological factors. It means the externalization of physiological functions especially of those from the autonomous nervous system so that a patient becomes aware of them. In the case of the ventilated patient, it is assumed that the transformation of the respiratory activities into perceptible (acoustic and visual) signals supports the patient's self-controlling behaviour during the weaning process. He gets positive reinforcement for his efforts to influence his breathing intentionally and, by continuous and immediate information, he regains self-confidence to control his somatic functions effectively. The application of biofeedback is mainly described in single case studies. They all report a decrease in the respiratory rate and an increase in the tidal volume. The need for a controlled study is suggested that would answer the question of whether biofeedback is an appropriate psychological tool to facilitate the weaning process in mechanically ventilated patients.     

Dermoscopy of scalp tumours: a multi‐centre study conducted by the international dermoscopy society

Background Little is known about the dermoscopic features of scalp tumours. Objective To determine the dermoscopic features of scalp tumours. Methods Retrospective analysis of dermoscopic images of histopathologically diagnosed scalp tumours from International Dermoscopy Society members. Results A total of 323 tumours of the scalp from 315 patients (mean age: 52 years; range 3–88 years) were analysed. Scalp nevi were significantly associated with young age (<30 years) and exhibited a globular or network pattern with central or perifollicular hypopigmentation. Melanoma and non‐melanoma skin cancer were associated with male gender, androgenetic alopecia, age >65 years and sun damage. Atypical network and regression were predictive for thin (≤1 mm) melanomas, whereas advanced melanomas (tumour thickness > 1 mm) revealed blue white veil, unspecific patterns and irregular black blotches or dots. Conclusions The data collected provide a new knowledge regarding the clinical and dermoscopy features of pigmented scalp tumours.