Mechanisms of insulin resistance in experimental hyperinsulinemic dogs

The aim of this work was to identify which proteins in horse dander extracts are allergens and to characterise them. Two-dimensional PAGE showed that horse dander preparations are composed of up to 50 proteins, all having acidic isoelectric points in the pH range 3-4.5. Immunoblots of two-dimensional PAGE were used to compare the reactivity of the proteins with IgE from 23 allergic patients. Patient sera were divided into two main groups recognising either allergens of 18.5 kDa or proteins of 27-29 and 31 kDa. The proteins of 27-29 kDa and 31 kDa were all N-glycosylated and their glycan chains seem to play a role in the binding of IgE from allergic patients. The sugar composition of their carbohydrate moiety was determined and lectin-binding experiments indicated presence of terminal sialic acid linked alpha-(2-->6) to galactose, galactose linked beta-(1-->4) to N-acetylglucosamine, and possibly presence of sialic acid linked alpha-(2-->3) to galactose. The 27-29-kDa glycoproteins had heterogeneous isoelectric points, most probably due to different degrees of sialylation in their oligosaccharide chains. The two 18.5-kDa allergens exhibited slightly different isoelectric points and their N-terminal sequences were identical, showing that they most likely were isoforms of the same protein. Sequence analyses revealed that their N-terminal sequences are similar to proteins belonging to the lipocalin family. We named the two 18.5-kDa proteins Equ c 2.0101 and Equ c 2.0102, according to International Allergen Nomenclature recommendations [King, T. P., Hoffman, D., Lowenstein, H., Marsh, D. G., Platts-Mills, T. A. E. & Thomas, W. (1995) J. Allergy Clin. Immunol. 96, 5-14]. The N-terminal of the allergens of 27-29 kDa were blocked and their sequences were not determined. Their amino acid compositions were determined and comparison with acidic mammalian proteins in the Swiss-Prot database revealed high scores with lipocalin proteins. This suggests that the glycosylated horse dander allergens belong to the lipocalin family, like Equ c 2.0101 and Equ c 2.0102.     

Hedgehog''s escape from Pandora''s box

The Hedgehog family of secreted glycoproteins proteins plays multifarious roles during vertebrate embryogenesis. In both the Drosophila and vertebrate embryo correct deployment of Hedgehog-like proteins is critical for the generation of pattern in many tissues and organs. New evidence now reveals that genes involved in hedgehog signalling are mutated in a number of common human genetic disorders, including skin cancer and craniofacial defects. The understanding of how cells generate, receive and transduce the Hedgehog signal during development has led to the establishment of molecular paradigms for the pathogenesis of these diseases. These studies clearly illustrate that knowledge of the normal role of a gene during development is critical for generating an understanding of the disease state in which it is mutated.     

Meprin A, the major matrix degrading enzyme in renal tubules, produces a novel nidogen fragment in vitro and in vivo

We examined the effect of meprin A, the major matrix degrading metalloproteinase in rat kidney, on the laminin-nidogen complex. N-terminal sequence information from the most abundant 55 kDa fragment revealed that it was a breakdown product of nidogen rather than laminin. In comparison with over 50 nidogen cleavage sites produced by other proteases, the meprin A-induced nidogen cleavage site at amino acid position 899-900, a glutamine-glycine site in the G3 domain, is unique. In addition, these data demonstrate that meprin A degrades the G3 domain of nidogen even in the presence of laminin binding, which usually accords protection from proteolytic degradation. Meprin A also degraded purified nidogen into similar breakdown products. Given that the tubular basement membrane is located on the basilar side of the cell, the location of meprin A on the apical brush border makes it difficult to envision a role for meprin A in injury-induced basement membrane component breakdown. Thus, we examined the possibility that following renal tubular epithelial cell injury, meprin A undergoes a translocation to reach the underlying basement membrane. After renal ischemia-reperfusion there was a marked alteration in meprin A staining with meprin A now distributed throughout the renal tubular cell cytoplasm and directly adherent to the tubular basement membrane. This was in contrast to the usual linear staining of the brush border of tubules in the corticomedullary junction. These data provide unequivocal evidence that following injury, meprin A undergoes redistribution and/or adherence to the tubular basement membrane. Since in our in vitro studies, we identified a distinct meprin-induced 55 kDa nidogen breakdown product, the urine was also examined for the presence of nidogen degradation products after rat renal ischemia-reperfusion injury. Western blots showed a marked increase in the urinary 55 kDa nidogen fragment as early as the first day following ischemia-reperfusion injury and continuing for six days. Taken together, these in vivo data strongly support the notion that the nidogen breakdown products are the result of partial degradation of tubular basement membrane by meprin A following renal tubular ischemia-reperfusion injury.     

Peripheral O2 diffusion does not affect V(O2)on-kinetics in isolated insitu canine muscle

To test the hypothesis that muscle O2 uptake (V(O2)) on-kinetics is limited, at least in part, by peripheral O2 diffusion, we determined the V(O2) on-kinetics in 1) normoxia (Control); 2) hyperoxic gas breathing (Hyperoxia); and 3) hyperoxia and the administration of a drug (RSR-13, Allos Therapeutics), which right-shifts the Hb-O2 dissociation curve (Hyperoxia+RSR-13). The study was conducted in isolated canine gastrocnemius muscles (n = 5) during transitions from rest to 3 min of electrically stimulated isometric tetanic contractions (200-ms trains, 50 Hz; 1 contraction/2 s; 60-70% peak V(O2)). In all conditions, before and during contractions, muscle was pump perfused with constantly elevated blood flow (Q), at a level measured at steady state during contractions in preliminary trials with spontaneous Q x Adenosine was infused intra-arterially to prevent inordinate pressure increases with the elevated Q x Q was measured continuously, arterial and popliteal venous O2 concentrations were determined at rest and at 5- to 7-s intervals during contractions, and V(O2) was calculated as Q x arteriovenous O2 content difference. PO2 at 50% HbO2 saturation (P50) was calculated. Mean capillary PO2 (Pc(O2)) was estimated by numerical integration. P50 was higher in Hyperoxia+RSR-13 [40 +/- 1 (SE) Torr] than in Control and in Hyperoxia (31 +/- 1 Torr). After 15 s of contractions, Pc(O2) was higher in Hyperoxia (97 +/- 9 Torr) vs. Control (53 +/- 3 Torr) and in Hyperoxia+RSR-13 (197 +/- 39 Torr) vs. Hyperoxia. The time to reach 63% of the difference between baseline and steady-state V(O2) during contractions was 24.7 +/- 2.7 s in Control, 26.3 +/- 0.8 s in Hyperoxia, and 24.7 +/- 1.1 s in Hyperoxia+RSR-13 (not significant). Enhancement of peripheral O2 diffusion (obtained by increased PcO2 at constant O2 delivery) during the rest-to-contraction (60-70% of peak V(O2)) transition did not affect muscle V(O2) on- kinetics.     

Sensitivity analysis for simulation-based decision making: Application to a hospital emergency service design

An increasing concern of decision makers when dealing with system design is preparation for a wide range of potentially uncertain operating conditions. This paper provides a novel multiobjective approach for simulation-driven decision making that accounts for not only the conventional average system performance indices, but also (i) upper-tail, or extreme, values of these indices, and (ii) measures of their sensitivity to uncertainty in model parameters. The proposed approach is applied to a hospital emergency department service design case study wherein different design alternatives are compared using total time-in-system performance metric under multiple uncertain operating conditions.     

Empirische Methodologien und Methoden der angewandten und der empirischen Ethik

Definition of the problem This paper deals with the question of adequate methodologies and methods to conduct empirical research and integrate empirical knowledge in the field of biomedical ethics. Arguments It starts with reflections about the main subject matter of ethics, the human being as a bio-psycho-social creature and its morals, and argues that social sciences are the adequate basic empirical science in the field of ethics in general. The next paragraph considers theory of science perspectives of the relationship of ethics, empirical findings, methodologies and theories and examples of the integration of empirical findings into ethical deliberations. Reasons for the tension between social science and ethics are scrutinized which are different in the yet to be defined field of empirical ethics compared to traditional applied ethics. Conclusion How a bio-psycho-social ethics that incorporates these criteria into its own body of work could look like is finally depicted.     

SEMPA – Ein Ansatz des Semantischen Prozessmanagements zur Planung von Prozessmodellen

Currently process modeling is mostly done manually. Therefore, the initial design of process models as well as changes to process models which are frequently necessary to react to new market developments or new regulations are time-consuming tasks. In this paper we introduce SEMPA, an approach for the partly automatic planning of process models. Using ontologies to semantically describe actions – as envisioned in Semantic Business Process Management –, a process model for a specified problem setting can be created automatically. In comparison to existing planning algorithms our approach creates process models including control structures and is able to cope with complex and numerical input and output parameters of actions. The prototypical implementation as well as an example taken from the financial services domain illustrate the practical benefit of our approach.     

A systematic study of thiophene Langmuir-Blodgett films including new conjugated donor-acceptor molecules

Hemicyanine dyes are an extensively investigated group of materials which show promise for second-order non-linear optical properties; they have also proved to be good materials for deposition by the Langmuir-Blodgett technique. This work concerns a closely related group of materials which contain a thiophene moiety in place of the nitrogen heterocycle of the hemicyanine material. The synthesis of several groups of novel amphiphiles containing the thiophene moiety, and their subsequent screening as materials for deposition by the Langmuir Blodgett technique is described. General trends in the behaviour of the simplest materials are noted, whilst the report of the characterization of the more complex D--A thiophenes is extended to include data relating to the production of heterogeneous monolayer and alternate layer structures.