Utilization of Polyspecific Antiserum for Specific Radioimmunoassays: Radioimmunoassays for Rat Fetuin and Bikunin Were Developed by Using Antiserum Against Total Rat Serum Proteins

Polyspecific antiserum against total rat serum proteins was used to develop specific and sensitive radioimmunoassays for fetuin and bikunin, two minor protein components of rat plasma. The radioimmunoassays proved to be highly useful to trace bikunin and fetuin in the course of developing isolation procedures, since neither specific functional assays nor monospecific antisera were available. The two examples demonstrate that, in general, it will be possible to develop a specific and sensitive radioimmunoassay with antiserum raised against a crude antigen preparation, such as a body fluid or a tissue extract, provided that a minute amount of pure antigen is available for preparing the radioiodinated antigen

Multi-Scale Modelling and Simulation of Textile Reinforced Materials

Novel textile reinforced composites provide an extremely high adaptability and allow for the development of materials whose features can be adjusted precisely to certain applications. A successful structural and material design process requires an integrated simulation of the material behavior, the estimation of the effective properties which need to be assigned to the macroscopic model and the resulting features of the component. In this context two efficient modelling strategies - the Binary Model (Carter, Cox, and Fleck (1994)) and the Extended Finite Element Method (X-FEM) (Moës, Cloirec, Cartraud, and Remacle (2003)) - are used to model materials which exhibit a complex structure on the mesoscale. For these investigations the focus is set on composites made of glass fibers, thermoset or thermoplastic matrices and on the application of commingled thermoplastic and glass fibers. Homogenization techniques are applied to compute effective macroscopic stiffness parameters. Problems arising from a complex textile reinforcement architecture, e.g. bi- or multi-axial weft-knit, woven and braided fabrics, in combination with a high fiber volume fraction will be addressed and appropriate solutions are proposed. The obtained results are verified by experimental test data. The macroscopic stress and strain fields in a component are used for optimization of the construction and the material layout. These distributions are computed in a global structural finite element analysis. Based on the global fiber orientation the required macroscopic material properties obtained from homogenization on the meso-scale are mapped to the model of the structural part. The configuration of the fiber-orientation and textile shear deformation in complex structural components caused by the manufacturing process is determined by a three-dimensional optical measurement system

The nucleotide and partial amino acid sequences of rat fetuin

Fetuins are among the major plasma proteins, yet their biological role has remained elusive. Here we report the molecular cloning of rat fetuin and the sequence analysis of a full-length clone, RF619 of 1456 bp with an open reading frame of 1056 bp encoding 352 amino acid residues. The coding part of RF619 was identical with the cDNA sequence of the natural inhibitor of the insulin receptor tyrosine kinase from rat (pp63) except for four substitutions and a single base insertion causing divergence of the predicted protein sequences. Partial amino acid sequences of rat plasma fetuin were in agreement with the predictions based on the RF619 cDNA. Purified rat fetuin inhibited the insulin receptor tyrosine kinase in vitro. Therefore, we conclude that RF619 and pp63 cDNA encode the same protein, i.e. authentic rat fetuin which is a functional tyrosine kinase inhibitor

A Hepatic Protein, Fetuin-A, Occupies a Protective Role in Lethal Systemic Inflammation

A liver-derived protein, fetuin-A, was first purified from calf fetal serum in 1944, but its potential role in lethal systemic inflammation was previously unknown. This study aims to delineate the molecular mechanisms underlying the regulation of hepatic fetuin-A expression during lethal systemic inflammation (LSI), and investigated whether alterations of fetuin-A levels affect animal survival, and influence systemic accumulation of a late mediator, HMGB1.LSI was induced by endotoxemia or cecal ligation and puncture (CLP) in fetuin-A knock-out or wild-type mice, and animal survival rates were compared. Murine peritoneal macrophages were challenged with exogenous (endotoxin) or endogenous (IFN-γ) stimuli in the absence or presence of fetuin-A, and HMGB1 expression and release was assessed. Circulating fetuin-A levels were decreased in a time-dependent manner, starting between 26 h, reaching a nadir around 24-48 h, and returning towards base-line approximately 72 h post onset of endotoxemia or sepsis. These dynamic changes were mirrored by an early cytokine IFN-γ-mediated inhibition (up to 50-70%) of hepatic fetuin-A expression. Disruption of fetuin-A expression rendered animals more susceptible to LSI, whereas supplementation of fetuin-A (20-100 mg/kg) dose-dependently increased animal survival rates. The protection was associated with a significant reduction in systemic HMGB1 accumulation in vivo, and parallel inhibition of IFN-γ- or LPS-induced HMGB1 release in vitro.These experimental data suggest that fetuin-A is protective against lethal systemic inflammation partly by inhibiting active HMGB1 release

A new modelling approach based on Binary Model and X-FEM to investigate the mechanical behaviour of textile reinforced composites

The purpose of this paper is the presentation of a new efficient modelling strategy based on the combination of Binary Model and Extended Finite Element Method (X-FEM). It is applied to represent the internal architecture of textile reinforced composites where the resin-saturated fabric is characterised by a complex geometry. Homogenisation methods are used to compute the effective elastic material properties. Thereby, the discrete formulation of periodic boundary conditions is adapted regarding additional degrees of freedom used by finite elements which are based on the X-FEM. Finally, the results in terms of effective material properties reveal a good agreement with parameters obtained by experimental tests

Rat tyrosine kinase inhibitor shows sequence similarity to human <i>α</i>2-HS glycoprotein and bovine fetuin

Human alpha 2-HS glycoprotein and bovine fetuin, abundant proteins of fetal plasma, are structural members of the fetuin family within the cystatin superfamily. They are characterized by the presence of two N-terminally located cystatin-like units and a unique C-terminal sequence segment not present in the other members of the cystatin superfamily. Search for related sequences revealed that the natural inhibitor of the insulin receptor tyrosine kinase [Auberger, Falquerho, Contreres, Pages, Le Cam, Rossi &amp; Le Cam (1989) Cell (Cambridge, Mass.) 58, 631-640] shows sequence similarity to the mammalian fetuins. The sequence identity between rat tyrosine kinase inhibitor, human alpha 2-HS glycoprotein and bovine fetuin is 56 and 60% respectively (percentage of residues in identical positions). The sequence similarity extends over the entire protein structures, except the extreme C-terminal portions. In particular, the number and relative positions of the cysteine residues are invariant among the proteins, suggesting that the characteristic array of linearly arranged and tandemly repeated disulphide loops of the cystatin superfamily is also present in rat tyrosine kinase inhibitor. We conclude that rat tyrosine kinase inhibitor may be classified as a novel member of the mammalian fetuin family.</jats:p

Progress towards assessing the contemporary evolution of the Greenland ice sheet.

A more accurate assessment of the contemporary evolution of the Greenland ice sheet and its major drainage basins requires a close interaction between observational data and modeling. The main challenge when interpreting satellite and observational data is to separate the ice mass contribution from the contribution of postglacial isostatic rebound, to separate ice-sheet dynamic changes from interannual surface mass balance changes, and to separate long-term ice-dynamic changes from short-term flow fluctuations. Here we report from recent progress towards these goals within the DFG SPP 1257 project 'Assessing the current evolution of the Greenland ice sheet' from studies combining observational data with glaciological modeling. This comprises studies to reconstruct the surface mass balance of the Greenland ice sheet between 1866 and 2006, optical satellite data from ASTER to obtain surface velocities, modelled balance velocities, and simulations with a three-dimensional thermomechanical ice-sheet model. In combination with GRACE data, these studies are expected to contribute to an improved estimate of the present-day contribution of the Greenland ice sheet to global sea-level change and a better understanding of the various contributions to current ice mass changes and their associated uncertainties