Elevation in Body Temperature to Fever Range Enhances and Prolongs Subsequent Responsiveness of Macrophages to Endotoxin Challenge

Macrophages are often considered the sentries in innate immunity, sounding early immunological alarms, a function which speeds the response to infection. Compared to the large volume of studies on regulation of macrophage function by pathogens or cytokines, relatively little attention has been devoted to the role of physical parameters such as temperature. Given that temperature is elevated during fever, a long-recognized cardinal feature of inflammation, it is possible that macrophage function is responsive to thermal signals. To explore this idea, we used LPS to model an aseptic endotoxin-induced inflammatory response in BALB/c mice and found that raising mouse body temperature by mild external heat treatment significantly enhances subsequent LPS-induced release of TNF-α into the peritoneal fluid. It also reprograms macrophages, resulting in sustained subsequent responsiveness to LPS, i.e., this treatment reduces “endotoxin tolerance” in vitro and in vivo. At the molecular level, elevating body temperature of mice results in a increase in LPS-induced downstream signaling including enhanced phosphorylation of IKK and IκB, NF-κB nuclear translocation and binding to the TNF-α promoter in macrophages upon secondary stimulation. Mild heat treatment also induces expression of HSP70 and use of HSP70 inhibitors (KNK437 or Pifithrin-µ) largely abrogates the ability of the thermal treatment to enhance TNF-α, suggesting that the induction of HSP70 is important for mediation of thermal effects on macrophage function. Collectively, these results support the idea that there has been integration between the evolution of body temperature regulation and macrophage function that could help to explain the known survival benefits of fever in organisms following infection

Ecoacoustics and multispecies semiosis: naming, semantics, semiotic characteristics, and competencies

Biosemiotics to date has focused on the exchange of signals between organisms, in line with bioacoustics; consideration of the wider acoustic environment as a semiotic medium is under-developed. The nascent discipline of ecoacoustics, that investigates the role of environmental sound in ecological processes and dynamics, fills this gap. In this paper we introduce key ecoacoustic terminology and concepts in order to highlight the value of ecoacoustics as a discipline in which to conceptualise and study intra- and interspecies semiosis. We stress the inherently subjective nature of all sensory scapes (vivo-, land-, vibro- and soundscapes) and propose that they should always bear an organismic attribution. Key terms to describe the sources (geophony, biophony, anthropophony, technophony) and scales (sonotopes, soundtopes, sonotones) of soundscapes are described. We introduce epithets for soundscapes to point to the degree to which the global environment is implicated in semiosis (latent, sensed and interpreted soundscapes); terms for describing key ecological structures and processes (acoustic community, acoustic habitat, ecoacoustic events) and examples of ecoacoustic events (choruses and noise) are described. The acoustic eco-field is recognized as the semiotic model that enables soniferous species to intercept core resources like food, safety and roosting places. We note that whilst ecoacoustics to date has focused on the critical task of the development of metrics for application in conservation and biodiversity assessment, these can be enriched by advancing conceptual and theoretical foundations. Finally, the mutual value of integrating ecoacoustic and biosemiotics perspectives is considered

Simulating non-isothermal water vapour transfer : an experimental validation on multi-layered building components

The aim of this study is to validate different analytical relations used in hygrothermal simulations for the material properties. Therefore, a valida tion experiment on four types of flat roofs has been set up at the laboratory. All rele vant material properties of the individual material layers were determined before hand. During the experiment, temperatures, heat fluxes and moisture contents were measured. The measured data were then compared with numerical simulation results. By repeating the simulations with different expressions for the vapour per meability and for the sorption isotherm, the influence of approximate analytic rela tionships was investigated

Brick cavity walls: A performance analysis based on measurements and Simulations

After world war two, cavity walls became a widespread external wall type in the cool but humid climate of North Western Europe. Moisture tolerance of the unfilled construction was excellent. Instead, calculation and testing underlined that the unfilled cavity walls of that era performed poorly from a thermal insulation point of view. After the energy crisis of 1973, cavity filling was therefore introduced as the main upgrade. Hence, extensive testing revealed upgrading was less simple than expected. Air in- and exfiltration through the wall, wind washing behind the fill, thermal stack induced air looping around the fill and thermal bridging all cooperated in lowering expected thermal quality of the filled walls. Anyhow, at the same time testing underlined that moisture tolerance remained outstanding in the cool, humid climate of North Western Europe also without cavity ventilation. That resulted in a set of recommendations how to construct high performing filled cavity walls. SAGE Publications 2007