Towards a social and context-aware multi-sensor fall detection and risk assessment platform.

For elderly people fall incidents are life-changing events that lead to degradation or even loss of autonomy. Current fall detection systems are not integrated and often associated with undetected falls and/or false alarms. In this paper, a social- and context-aware multi-sensor platform is presented, which integrates information gathered by a plethora of fall detection systems and sensors at the home of the elderly, by using a cloud-based solution, making use of an ontology. Within the ontology, both static and dynamic information is captured to model the situation of a specific patient and his/her (in)formal caregivers. This integrated contextual information allows to automatically and continuously assess the fall risk of the elderly, to more accurately detect falls and identify false alarms and to automatically notify the appropriate caregiver, e.g., based on location or their current task. The main advantage of the proposed platform is that multiple fall detection systems and sensors can be integrated, as they can be easily plugged in, this can be done based on the specific needs of the patient. The combination of several systems and sensors leads to a more reliable system, with better accuracy. The proof of concept was tested with the use of the visualizer, which enables a better way to analyze the data flow within the back-end and with the use of the portable testbed, which is equipped with several different sensors.

Targeting neonatal ischemic brain injury with a pentapeptide-based irreversible caspase inhibitor.

Brain protection of the newborn remains a challenging priority and represents a totally unmet medical need. Pharmacological inhibition of caspases appears as a promising strategy for neuroprotection. In a translational perspective, we have developed a pentapeptide-based group II caspase inhibitor, TRP601/ORPHA133563, which reaches the brain, and inhibits caspases activation, mitochondrial release of cytochrome c, and apoptosis in vivo. Single administration of TRP601 protects newborn rodent brain against excitotoxicity, hypoxia-ischemia, and perinatal arterial stroke with a 6-h therapeutic time window, and has no adverse effects on physiological parameters. Safety pharmacology investigations, and toxicology studies in rodent and canine neonates, suggest that TRP601 is a lead compound for further drug development to treat ischemic brain damage in human newborns.

Targeted Vpr-derived peptides reach mitochondria to induce apoptosis of alphaVbeta3-expressing endothelial cells.

The HIV-1 encoded apoptogenic protein Vpr induces mitochondrial membrane permeabilization (MMP) via interactions with the voltage-dependent anion channel (VDAC) and the adenine nucleotide translocator (ANT). We have designed a peptide, TEAM-VP, composed of two functional domains, one a tumor blood vessel RGD-like 'homing' motif and the other an MMP-inducing sequence derived from Vpr. When added to isolated mitochondria, TEAM-VP interacts with ANT and VDAC, reduces oxygen consumption and overcomes Bcl-2 protection to cause inner and outer MMP. TEAM-VP specifically recognizes cell-surface expressed alpha(V)beta(3) integrins, internalizes, temporarily localizes to lysosomes and progressively co-distributes with the mitochondrial compartment with no sign of lysosomal membrane permeabilization. Finally TEAM-VP reaches mitochondria of angiogenic endothelial cells to induce mitochondrial fission, dissipation of the mitochondrial transmembrane potential (DeltaPsi(m)), cytochrome c release and apoptosis hallmarks. Hence, this chimeric peptide constitutes the first example of a virus-derived mitochondriotoxic compound as a candidate to kill selectively tumor neo-endothelia.

Structural basis of the cross-reaction between an antibody to the Trypanosoma cruzi ribosomal P2beta protein and the human beta1 adrenergic receptor.

Antibodies from patients with Chagas heart disease and monoclonal antibodies (or mAb) to the carboxy-terminal end (B cell epitope R13) of the ribosomal P2beta protein of Trypanosoma cruzi (TcP2beta) cross-react with the beta1 adrenergic receptor (beta1-AR). Two single-chain Fv fragments (scFv) C5 and B7 derived from the variable regions of the anti-R13 mAb 17.2 were expressed. scFv C5 was a dimer and bound to TcP2beta with an affinity of K(d) = 8 nM, whereas scFv B7 was monomeric and had less affinity than scFv C5 for TcP2beta, K(d) = 46 nM. The affinity constant of scFv C5 to the second extracellular loop of the human beta1-AR was of 10 microM. Moreover, scFv C5 induced an increase in cAMP levels of CHO-K cells transfected with the human beta1-AR; scFv B7 had no effect but blocked isoproterenol stimulation. The agonist-like activity of scFv C5 and the antagonist activity of scFv B7 were both confirmed in vivo on heart beating frequency after their passive transfer to mice. Molecular modeling of the variable region of mAb 17.2 indicated which amino acids were likely to be involved in recognizing both peptide EDDDMGFGLF, derived from the R13 epitope of TcP2beta, and peptide ESDEARRCYN from the second extracellular loop of the human beta1-AR. It is plausible that the recently described cross-reaction of mAb 17.2 with rhodopsin can also be explained by this model. The physiological effects of this type of anti-T. cruzi antibodies may increase the liability of patients with Chagas disease.

The N-terminus of HIV-1 Tat protein is essential for Tat-TAR RNA interaction.

The human HIV transactivator protein Tat is essential for efficient viral transcription that occurs by a complex mechanism involving interaction of Tat with the TAR RNA element. This interaction appears to require the mediation of a cellular protein, cyclin T1. However, the possibility that Tat and TAR associate in a binary Tat-TAR complex has been little investigated. Using a chemically synthesized active Tat protein, the kinetic and equilibrium parameters of its interaction with TAR were determined by surface plasmon resonance technology. Independently of partner and method of immobilization onto the sensor chip, the association (k(a) = 5-9 x 10(5) M(-1) s(-1)) and dissociation rate constants (k(d) = 1.7-4.3 x 10(-3) s(-1)) yielded similar equilibrium dissociation constants (K(d) = 2-8 nM). A truncated peptide encompassing residues 30-86 of Tat did not bind to TAR at all. We conclude that Tat can form a high-affinity complex with TAR in the absence of cyclin T1 and that the N-terminal domain of Tat is essential for this interaction, suggesting a conformational link between this domain and the basic domain of Tat. These results are important in our quest for developing therapeutic compounds that impair viral replication.

Structural and functional complexity of the humoral response against the Trypanosoma cruzi ribosomal P2 beta protein in patients with chronic Chagas' heart disease.

High levels of antibodies against the C-terminus of the Trypanosoma cruzi TcP2 beta ribosomal protein, defined by the peptide EEEDDDMGFGLFD, named R13, have been measured in sera from patients with chronic Chagas' Heart Disease (cChHD). These antibodies also recognize an epitope on the second extracellular loop of the beta 1-adrenergic receptor, inducing a functional response on cardiomyocytes. The aim of this study was to gain novel insights into the structural basis of this cross-reactivity as well as to evaluate the origin of anti-M2- cholinergic receptor antibodies, which are also commonly found in cChHD patients. To address these questions we immunopurified anti-R13 antibodies and studied the structural requirements of epitope recognition. Results showed that the immunopurified antibodies recognized a conformation of R13 in which the third Glu residue was essential for binding, explaining their low affinity for the mammalian homologue (peptide H13: EESDDDMGFGLFD). Alanine mutation scanning showed individual variations in epitope recognition in each of the studied patients. The importance of a negatively charged residue at position 3 for the recognition of anti-R13 antibodies was further confirmed by competition experiments using a Ser3-phosphorylated H13 analogue, which had 10 times more affinity for the anti-R13 antibody than the native H13 peptide. Moreover, anti-R13 antibodies stimulated either the beta 1-adrenergic or the M2-cholinergic receptor, in strict agreement with the functional properties of the IgG fractions from which they derived, demonstrating that the same parasite antigen may generate antibody specificities with different functional properties. This may be a clue to explain the high variability of electrophysiological disturbances found in cChHD.

Immunogenicity of polymerizable synthetic peptides derived from a vaccine candidate against schistosomiasis: the asparaginyl endopeptidase (Sm32).

The asparaginyl endopeptidase (Sm32) is expressed in the gastrodermal cells of the schistosome gut and in the head glands of the cercariae. Possibly, Sm32 hydrolyzes pro-proteins involved in the degradation of host hemoglobin [Parasitol. Today 12 (1996) 125]. Preliminary evidences using an Sj32/Sm32 murine vaccine have shown a profound effect on oviposition and worm burden [Chin. J. Schist. Control. 7 (1995) 72; Bull. Human Med. Univ. 24 (1999) 225; Vaccine 20 (2002) 439]. The importance of Sm32 as a novel vaccine candidate is based on the possibility of preventing the maturation of other cathepsins and/or preventing schistosome skin invasion. We studied the immunogenicity of polymerizable peptides derived from Sm32 to select potential protective epitopes. Sm32 prediction of T and B epitopes and homology studies with human legumain were performed. Among the variety of factors that influence the antibody response, we specifically examined the effect of: (i) genetic background of mouse strain, inbred (C57BL/6) versus outbred (Swiss) mice; and (ii) vaccination with a single peptide versus pool of peptides. Swiss mice raised antibodies to three different regions of the Sm32, as tested by the Multiple Antigen Blot Assay (MABA): 182-215 (peptides IMT-70 and 72), 244-273 (IMT-64) and 336-355 (IMT-66). None of these regions were immunogenic for C57BL/6. On the contrary, other peptides, IMT-4 (21-40), IMT-12 (101-120) and IMT-26 (292-313) were highly immunogenic for this inbred strain. Only Swiss mice immunized with a single peptide (IMT-64 and 72) or with three different pools of IMT-peptides (Pool A-II: 14, 16, 18, 70, 72, 89; pool A-III: 22, 64, 24, 26, 28 and pool A-V: 64, 66, 28, 70, 72) recognized the original protein in a crude extract of the worm antigen by Western blot. Peptides IMT-64, 14 and 26 were responsible for this recognition. In general, the vaccination with pool of peptides was more immunogenic for both mouse strains. Predicted B cell epitopes, with hydrophilicity scores over +10 (IMT-12, 64, 26) were always immunogenic after either single or combined peptide vaccination. Sm32 sequences 41-80 (IMT-6 and 8), 141-160 (IMT-16) and 182-215 (IMT-70 and 72) were nearly identical to the corresponding human legumain regions and should be excluded from the human vaccine. We can conclude that the regions of Sm32 that were recognized by antibodies of mice immunized with polymerizable peptides depended on the mice strain and on the hydrophilicity score of the peptides.

A novel retro-inverso gonadotropin-releasing hormone (GnRH) immunogen elicits antibodies that neutralize the activity of native GnRH.

GnRH vaccines have been successfully used for the inhibition of gonadotropin secretion and gonadal function. As an alternative to native GnRH, retro-inverso (RI) GnRH might be an improved immunogen. The RI peptides are composed of D-amino acids assembled in the reverse order (C to N terminus) in relation to the parent L peptide. These peptides are immunogenic and can produce high titers of antibodies that bind the parent peptide with high affinity and specificity. We show that RI-GnRH peptides conjugated to ovalbumin as well as unconjugated RI-GnRH elicit high titers of anti-GnRH antibodies in rabbits and mice. Antibodies were affinity purified and shown by ELISA to be selective for mammalian GnRH compared with GnRH II and [Gln(8)]GnRH. The binding kinetics of antibody-peptide interactions was determined using biosensor technology (BIACORE). The purified anti-GnRH antibodies inhibited GnRH-stimulated signal transduction in COS-1 cells expressing the human GnRH receptor. Immunization of mice with unconjugated and conjugated RI-GnRH peptide, in the absence of complete Freund's adjuvant, produced antisera that cross-reacted with mammalian GnRH. As RI peptides are resistant to cleavage by proteolytic enzymes, they are potentially orally active. The ability of RI-GnRH peptides to produce antibodies to GnRH without conjugation and without Freund's complete adjuvant constitutes a novel vaccine with improved properties of potential application in animal management and sex hormone-dependent cancers.

Agonist-like activity of antibodies directed against the second extracellular loop of the human cardiac serotonin 5-HT4(e) receptor in transfected COS-7 cells.

We have previously reported that antipeptide antibodies directed against the second extracellular loop of the cardiac h5-HT4 receptor could block the activation of the L-type Ca channel in human atrial cardiomyocytes. In this paper we investigate the immunological and physiological activity of these antibodies, in a cell system expressing a larger amount of receptors than the atrial cells. The recombinant receptor was expressed at the surface of COS-7 cells under an active form (serotonin, EC50 = 1.81 x 10(-7) M), at a high level (375 +/- 25 fmol receptor/mg total protein) and was able to bind a specific ligand (GR113808) with a high affinity (Kd = 0.28 +/- 0.05 nM). In this system, the same anti-peptide antibodies used for the cardiac cells induced an "agonist-like" effect on the recombinant h5-HT4 receptor. These results are in line with those shown for others G-protein coupled receptors, as adrenoreceptors. In addition, this work showed that the effect of the antibodies is not only dependent on the epitopic region recognised but also on the molecular density and/or the cellular environment of the target receptors. Finally, our results support the hypothesis that the h5-HT4 receptor could be a new target for autoantibodies in patients with atrial arrhythmia.