Search results for " System P"
showing 10 items of 181 documents
Compensating for instantaneous signal mixing in transfer entropy analysis of neurobiological time series
2013
The transfer entropy (TE) has recently emerged as a nonlinear model-free tool, framed in information theory, to detect directed interactions in coupled processes. Unfortunately, when applied to neurobiological time series TE is biased by signal cross-talk due to volume conduction. To compensate for this bias, in this study we introduce a modified TE measure which accounts for possible instantaneous effects between the analyzed time series. The new measure, denoted as compensated TE (cTE), is tested on simulated time series reproducing conditions typical of neuroscience applications, and on real magnetoencephalographic (MEG) multi-trial data measured during a visuo-tactile cognitive experime…
Functional analysis of the classical, alternative, and MBL pathways of the complement system: standardization and validation of a simple ELISA.
2004
Primary defence against invading microorganisms depends on a functional innate immune system and the complement system plays a major role in such immunity. Deficiencies in one of the components of the complement system can cause severe and recurrent infections, systemic diseases, such as systemic lupus erythematosus (SLE) and renal disease. Screening for complement deficiencies in the classical or alternative complement pathways has mainly been performed by haemolytic assays. Here, we describe a simple ELISA-based format for the evaluation of three pathways of complement activation. The assays are based on specific coatings for each pathway in combination with specific buffer systems. We ha…
T cell factor (interleukin 2) allows in vivo induction of T helper cells against heterologous erythrocytes in athymic (nu/nu) mice.
1980
Mice carrying the nude mutation (nu/nu) lack a functioning thymus and do not contain detectable levels of immunocompetent T cells. We now report that nu/nu mice do have lymphocytes which can be activated in vivo by heterologous erythrocytes and a Lyt-1 T cell-derived factor (interleukin 2) to generate T helper cells. Thus, a lymphokine is described which is able to restore in vivo T helper cell immunocompetence of nu/nu mice. The data may suggest that nu/nu mice contain a low number of T lymphocytes influenced by the cystic remnant of the nu/nu thymus anlage. Alternatively, the data imply that interleukin 2 circumvents the requirement of a thymus during ontogeny of T lymphocytes.
A dynamic performance management approach to frame corruption in public procurement: a case study
2021
Purpose The purpose of this paper is to frame the causal relationships between corruption in public procurement and performance of local governments. Design/methodology/approach An outcome-based dynamic performance management approach is adopted to explore a representative case study of a small Italian municipality. The model is based on three sources: qualitative primary data generated by face-to-face convergent interviews; secondary data retrieved from documents describing legal cases linked to procurement and open-access repositories; and an extensive literature review. Findings Emphasizing the role of community civic morality systemically may help to understand some counterintuitive re…
Managing information security in a business network of machinery maintenance services business – Enterprise architecture as a coordination tool
2007
Today, technologies enable easy access to information across organizational boundaries, also to systems of partners in business networks. This raises, however, several complex research questions on privacy, information security and trust. The study reported here provides motivation and a roadmap for approaching integrated security management solutions in a business network of partners with heterogeneous information and communication technologies (ICT): Systems, platforms, infrastructures as well as security policies. Enterprise architecture (EA) is proposed as a means for comprehensive and coordinated planning and management of corporate ICT and the security infrastructure. The EA approach …
COMPLEMENT-DEPENDENT B-CELL ACTIVATION BY COBRA VENOM FACTOR AND OTHER MITOGENS?
1974
It has been proposed that two distinct signals are required for the triggering of the precursors of antibody-forming bone marrow-derived cells (B cells): (a) the binding of antigen or of a mitogen to the corresponding receptor sites on B-cell membranes and (b) the interaction of activated C3 with the C3 receptor of B lymphocytes. There is growing evidence that B-cell mitogens and T (thymus-derived cell)-independent antigens are capable of activating the alternate pathway of the complement system (bypass). Therefore, the effect of another potent bypass inducer was investigated with regard to B-cell activation and the role of C3. Purified, pyrogen-free cobra venom factor was mitogenic for bot…
New clinical and pathophysiological perspectives defining the trajectory of cirrhosis
2021
Traditionally, the complications of cirrhosis, namely variceal bleeding, ascites and hepatic encephalopathy, were thought to result predominantly from circulatory dysfunction and altered organ perfusion arising as a result of portal hypertension. Over the past 20 years, large, international prospective studies have indicated the importance of systemic inflammation and organ immunopathology as additional determinants of organ dysfunction in cirrhosis, which not only manifests in the liver, brain, circulation and the kidneys, but also the immune system, gut, muscles, adrenal glands, reproductive organs, heart and lungs. This review provides an overview of the traditional and emerging concepts…
Complement pore genesis observed in erythrocyte membranes by fluorescence microscopic single-channel recording
1991
The formation and opening of single complement pores could be directly observed in erythrocyte ghosts by confocal laser-scanning microscopy employing the recently introduced method of fluorescence microscopic single-channel recording. Resealed sheep erythrocyte ghosts were incubated with human complement. By limiting the concentration of C8, the eighth component of complement, the fraction of cells rendered permeable for the small polar fluorescent probe Lucifer Yellow was varied between 0.50 and 0.90. Under each condition the flux rate, k, of Lucifer Yellow was determined for a substantial number of ghosts. By analysing the sample population distribution of k the flux rate k1 of ghosts wit…
Histamine and its possible role in cytolysis of white blood cells in guinea pigs sensitized with tubercle bacilli.
1962
DELAYED or tuberculin-type sensitivity is–apart from some single publications–only transferable by white blood cells or peritoneal cells but not with humoral antibodies of sensitized organisms1. In vitro, after addition of antigen, a lysis of white blood cells2 is seen up to 35 per cent2. That effect is preceded by morphological changes3–5. Cytolysis in the presence of plasma will be discussed elsewhere. Labelled lymphoid cells of sensitized guinea pigs will be found after transfer to normal animals at the side of the dermal tuberculin reaction6. The importance of white cells is further revealed by the fact that the tuberculin reaction will be suppressed by a specific anti-lymphocytic serum…
Effect of in vivo stimulation of mice on the secretion of factor B of the alternative complement pathway by peritoneal macrophages
1977
After in vivo treatment of mice with thioglycollate medium, the amount of native factor B which could be detected in vitro in culture supernatants of peritoneal macrophages was much lower than that found in supernatants of macrophages taken from untreated mice. However, when the macrophages from thioglycollate medium-treated mice were cultured on a plastic surface covered with glutardialdehyde-linked bovine serum albumin, the culture supernatants contained larger quantities of native factor B than culture supernatants of macrophages from untreated mice under the same conditions. Thus, the effect of in vivo thioglycollate medium treatment on the in vitro secretion of factor B by peritoneal m…