Tissue Vitronectin in Normal Adult Human Dermis Is Non-Covalently Bound to Elastic Tissue

Vitronectin is a multifunctional human plasma glycoprotein at is also found in constant association with elastic tissue fibers in normal adults. We have investigated the nature of the association of vitronectin with elastic tissue, and compared it to that of other elastic fiber-associated proteins, namely fibrillin and amyloid P component. Samples of normal human dermis were incubated with a variety of extraction agents, including high molar salt solution, non-ionic detergent (Nonidet P-40), the reducing agents dithiothreitol or 2-mercaptoethanol, and the chaotropic agents sodium dodecyl sulfate or guanidine hydrochloride. Vitronectin purified from serum typically migrates as two bands of 75 and 65 kD. By contrast, immunoblotting studies of residual dermal material after extraction with the various agents revealed only lower molecular weight (58, 50, 42, 35, and 27 kD) anti-vitronectin reactive bands. Although these bands may represent degradation products of vitronectin generated as a result of the extraction procedure, we cannot exclude the possibility that tissue vitronectin is distinct from plasma vitronectin. Anti-vitronectin reactive polypeptides co-migrating with the 58-, 50-, and 42-kD bands were solubilized following extraction with sodium dodecyl sulfate or guanidine hydrochloride, but not with the other extraction agents. Immunofluorescence studies using residual dermal material after extraction with guanidine hydrochloride demonstrated a marked reduction in elastic fiber staining intensity with anti-vitronectin and anti-amyloid P component, but not with anti-fibrillin. Thus the majority, if not all of dermal vitronectin, is, like amyloid P component, non-covalently associated with, and not an integral constituent of, elastic fibers

Identification of glycosaminoglycan binding regions in the Plasmodium falciparum encoded placental sequestration ligand, VAR2CSA

<p>Abstract</p> <p>Background</p> <p>Pregnancy malaria is caused by <it>Plasmodium falciparum</it>-infected erythrocytes binding the placental receptor chondroitin sulfate A (CSA). This results in accumulation of parasites in the placenta with severe clinical consequences for the mother and her unborn child. Women become resistant to placental malaria as antibodies are acquired which specifically target the surface of infected erythrocytes binding in the placenta. VAR2CSA is most likely the parasite-encoded protein which mediates binding to the placental receptor CSA. Several domains have been shown to bind CSA <it>in vitro</it>; and it is apparent that a VAR2CSA-based vaccine cannot accommodate all the CSA binding domains and serovariants. It is thus of high priority to define minimal ligand binding regions throughout the VAR2CSA molecule.</p> <p>Methods</p> <p>To define minimal CSA-binding regions/peptides of VAR2CSA, a phage display library based on the entire <it>var2csa </it>coding region was constructed. This library was screened on immobilized CSA and cells expressing CSA resulting in a limited number of CSA-binding phages. Antibodies against these peptides were affinity purified and tested for reactivity against CSA-binding infected erythrocytes.</p> <p>Results</p> <p>The most frequently identified phages expressed peptides residing in the parts of VAR2CSA previously defined as CSA binding. In addition, most of the binding regions mapped to surface-exposed parts of VAR2CSA. The binding of a DBL2X peptide to CSA was confirmed with a synthetic peptide. Antibodies against a CSA-binding DBL2X peptide reacted with the surface of infected erythrocytes indicating that this epitope is accessible for antibodies on native VAR2CSA on infected erythrocytes.</p> <p>Conclusion</p> <p>Short continuous regions of VAR2CSA with affinity for multiple types of CSA were defined. A number of these regions localize to CSA-binding domains and to surface-exposed regions within these domains and a synthetic peptide corresponding to a peptide sequence in DBL2 was shown to bind to CSA and not to CSC. It is likely that some of these epitopes are involved in native parasite CSA adhesion. However, antibodies directed against single epitopes did not inhibit parasite adhesion. This study supports phage display as a technique to identify CSA-binding regions of large proteins such as VAR2CSA.</p

Differential Induction of Functional IgG Using the Plasmodium falciparum Placental Malaria Vaccine Candidate VAR2CSA

BACKGROUND: In Plasmodium falciparum malaria endemic areas placental malaria (PM) is an important complication of malaria. The recurrence of malaria in primigravidae women irrespective of acquired protection during childhood is caused by the interaction between the parasite-expressed VAR2CSA antigen and chondroitin sulfate A (CSA) in the placental intervillous space and lack of protective antibodies. PM impairs fetal development mainly by excessive inflammation processes. After infections during pregnancy women acquire immunity to PM conferred by antibodies against VAR2CSA. Ideally, a vaccine against PM will induce antibody-mediated immune responses that block the adhesion of infected erythrocytes (IE) in the placenta. PRINCIPAL FINDINGS: We have previously shown that antibodies raised in rat against individual domains of VAR2CSA can block IE binding to CSA. In this study we have immunized mice, rats and rabbits with each individual domain and the full-length protein corresponding to the FCR3 VAR2CSA variant. We found there is an inherently higher immunogenicity of C-terminal domains compared to N-terminally located domains. This was irrespective of whether antibodies were induced against single domains or the full-length protein. Species-specific antibody responses were also found, these were mainly directed against single domains and not the full-length VAR2CSA protein. CONCLUSIONS/SIGNIFICANCE: Binding inhibitory antibodies appeared to be against conformational B-cell epitopes. Non-binding inhibitory antibodies reacted highly against the C-terminal end of the VAR2CSA molecule especially the highly polymorphic DBL6ε domain. Differential species-specific induction of antibody responses may allow for more direct analysis of functional versus non-functional B-cell epitopes

A Pilot Study with a Novel Setup for Collaborative Play of the Humanoid Robot KASPAR with children with autism

This article is distributed under the terms of the Creative Commons Attribution License which permits any use, distribution, and reproduction in any medium, provided the original author(s) and the source are credited.This article describes a pilot study in which a novel experimental setup, involving an autonomous humanoid robot, KASPAR, participating in a collaborative, dyadic video game, was implemented and tested with children with autism, all of whom had impairments in playing socially and communicating with others. The children alternated between playing the collaborative video game with a neurotypical adult and playing the same game with the humanoid robot, being exposed to each condition twice. The equipment and experimental setup were designed to observe whether the children would engage in more collaborative behaviours while playing the video game and interacting with the adult than performing the same activities with the humanoid robot. The article describes the development of the experimental setup and its first evaluation in a small-scale exploratory pilot study. The purpose of the study was to gain experience with the operational limits of the robot as well as the dyadic video game, to determine what changes should be made to the systems, and to gain experience with analyzing the data from this study in order to conduct a more extensive evaluation in the future. Based on our observations of the childrens’ experiences in playing the cooperative game, we determined that while the children enjoyed both playing the game and interacting with the robot, the game should be made simpler to play as well as more explicitly collaborative in its mechanics. Also, the robot should be more explicit in its speech as well as more structured in its interactions. Results show that the children found the activity to be more entertaining, appeared more engaged in playing, and displayed better collaborative behaviours with their partners (For the purposes of this article, ‘partner’ refers to the human/robotic agent which interacts with the children with autism. We are not using the term’s other meanings that refer to specific relationships or emotional involvement between two individuals.) in the second sessions of playing with human adults than during their first sessions. One way of explaining these findings is that the children’s intermediary play session with the humanoid robot impacted their subsequent play session with the human adult. However, another longer and more thorough study would have to be conducted in order to better re-interpret these findings. Furthermore, although the children with autism were more interested in and entertained by the robotic partner, the children showed more examples of collaborative play and cooperation while playing with the human adult.Peer reviewe

Increased risk of venous thrombosis by AB alleles of the ABO blood group and Factor V Leiden in a Brazilian population

Most cases of a predisposition to venous thrombosis are caused by resistance to activated protein C, associated in 95% of cases with the Factor V Leiden allele (FVL or R506Q). Several recent studies report a further increased risk of thrombosis by an association between the AB alleles of the ABO blood group and Factor V Leiden. The present study investigated this association with deep vein thrombosis (DVT) in individuals treated at the Hemocentro de Pernambuco in northeastern Brazil. A case-control comparison showed a significant risk of thrombosis in the presence of Factor V Leiden (OR = 10.1), which was approximately doubled when the AB alleles of the ABO blood group were present as well (OR = 22.3). These results confirm that the increased risk of deep vein thrombosis in the combined presence of AB alleles and Factor V Leiden is also applicable to the Brazilian population suggesting that ABO blood group typing should be routinely added to FVL in studies involving thrombosis

Genetic Background Analysis of Protein C Deficiency Demonstrates a Recurrent Mutation Associated with Venous Thrombosis in Chinese Population

Background: Protein C (PC) is one of the most important physiological inhibitors of coagulation proteases. Hereditary PC deficiency causes a predisposition to venous thrombosis (VT). The genetic characteristics of PC deficiency in the Chinese population remain unknown. Methods: Thirty-four unrelated probands diagnosed with hereditary PC deficiency were investigated. PC activity and antigen levels were measured. Mutation analysis was performed by sequencing the PROC gene. In silico analyses, including PolyPhen-2, SIFT, multiple sequence alignment, splicing prediction, and protein molecular modeling were performed to predict the consequences of each variant identified. One recurrent mutation and its relative risk for thrombosis in relatives were analyzed in 11 families. The recurrent mutation was subsequently detected in a case (VT patients)-control study, and the adjusted odds ratio (OR) for VT risk was calculated by logistic regression analysis. Results: A total of 18 different mutations, including 12 novel variants, were identified. One common mutation, PROC c.565C.T (rs146922325:C.T), was found in 17 of the 34 probands. The family study showed that first-degree relatives bearing this variant had an 8.8-fold (95%CI = 1.1–71.6) increased risk of venous thrombosis. The case-control (1003 vs. 1031) study identified this mutation in 5.88 % patients and in 0.87 % controls, respectively. The mutant allele conferred a high predisposition to venous thrombosis (adjusted OR = 7.34, 95%CI = 3.61–14.94). The plasma PC activity and antigen levels i

A gene-centric analysis of activated partial thromboplastin time and activated protein C resistance using the HumanCVD focused genotyping array.

Activated partial thromboplastin time (aPTT) is an important routine measure of intrinsic blood coagulation. Addition of activated protein C (APC) to the aPTT test to produce a ratio, provides one measure of APC resistance. The associations of some genetic mutations (eg, factor V Leiden) with these measures are established, but associations of other genetic variations remain to be established. The objective of this work was to test for association between genetic variants and blood coagulation using a high-density genotyping array. Genetic association with aPTT and APC resistance was analysed using a focused genotyping array that tests approximately 50 000 single-nucleotide polymorphisms (SNPs) in nearly 2000 cardiovascular candidate genes, including coagulation pathway genes. Analyses were conducted on 2544 European origin women from the British Women's Heart and Health Study. We confirm associations with aPTT at the coagulation factor XII (F12)/G protein-coupled receptor kinase 6 (GRK6) and kininogen 1 (KNG1)/histidine-rich glycoprotein (HRG) loci, and identify novel SNPs at the ABO locus and novel locus kallikrein B (KLKB1)/F11. In addition, we confirm association between APC resistance and factor V Leiden mutation, and identify novel SNP associations with APC resistance in the HRG and F5/solute carrier family 19 member 2 (SLC19A2) regions. In conclusion, variation at several genetic loci influences intrinsic blood coagulation as measured by both aPTT and APC resistance

Futures in the making: Practices to anticipate 'ubiquitous computing'

This paper addresses the discourse for a proactive thinking of futurity, intimately concerned with technology, which comes to an influential fruition in the discussion and representation of 'ubiquitous computing'. The imagination, proposal, or playing out of ubiquitous computing environments are bound up with particular ways of constructing futurity. This paper charts the techniques used in ubiquitous computing development to negotiate that futurity. In so doing, it engages with recent geographical debates around anticipation and futurity. The discussion accordingly proceeds in four parts. First, the spatial imagination engendered by the development of ubiquitous computing is explored. Second, particular techniques in ubiquitous computing research and development for anticipating future technology use, and their limits, are discussed through empirical findings. Third, anticipatory knowledge is explored as the basis for stable means of future orientation, which both generates and derives from the techniques for anticipating futures. Fourth, the importance of studying future orientation is situated in relation to the somewhat contradictory nature of anticipatory knowledges of ubicomp and related forms of spatial imagination. © 2012 Pion and its Licensors