Protein-mediated gelation and nano-scale assembly of unfunctionalized hyaluronic acid and chondroitin sulfate.

Background: Hyaluronic acid (HA) is a major component of the extracellular matrix (ECM) in the central nervous system and the only purely supramolecular glycosaminoglycan. Much focus has been given to using this high molecular weight polysaccharide for tissue engineering applications. In most studies, the backbone of HA is functionalized with moieties that can facilitate network formation through physical self-assembly, or covalent crosslinking (e.g. photo-catalyzed) at concentrations where the polysaccharide does not gel on its own. However, these crosslinks often utilize functional groups not found in biological tissues. Methods: Oscillatory rheology, dynamic light scattering, and scanning electron microscopy were used to study albumin/HA structures. Dynamic light scattering and transmission electron microscopy were used to study albumin/chondroitin sulfate (CS) structures. UV-vis spectroscopy was used to demonstrate the potential for using protein-polymer blends as an ECM-mimetic model to study transport of small molecules. Results: We examine the intermolecular interactions of two major glycosaminoglycans found in the human brain, HA and the lower molecular weight CS, with the model protein albumin. We report the properties of the resulting micro- and nano materials. Our albumin/HA systems formed gels, and albumin/CS systems formed micro- and nanoparticles. These systems are formed from unfunctionalized polysaccharides, which is an attractive and simple method of forming HA hydrogels and CS nanoparticles. We also summarize the concentrations of HA and CS found in various mammalian brains, which could potentially be useful for biomimetic scaffold development. Conclusions: Simple preparation of commercially available charged biomacromolecules results in interesting materials with structures at the micron and nanometer length-scales. Such materials may have utility in serving as cost-effective models of nervous system electrostatic interactions and as in vitro drug release and model system for ECM transport studies

Multidimensional signals and analytic flexibility: Estimating degrees of freedom in human speech analyses

Recent empirical studies have highlighted the large degree of analytic flexibility in data analysis which can lead to substantially different conclusions based on the same data set. Thus, researchers have expressed their concerns that these researcher degrees of freedom might facilitate bias and can lead to claims that do not stand the test of time. Even greater flexibility is to be expected in fields in which the primary data lend themselves to a variety of possible operationalizations. The multidimensional, temporally extended nature of speech constitutes an ideal testing ground for assessing the variability in analytic approaches, which derives not only from aspects of statistical modeling, but also from decisions regarding the quantification of the measured behavior. In the present study, we gave the same speech production data set to 46 teams of researchers and asked them to answer the same research question, resulting insubstantial variability in reported effect sizes and their interpretation. Using Bayesian meta-analytic tools, we further find little to no evidence that the observed variability can be explained by analysts’ prior beliefs, expertise or the perceived quality of their analyses. In light of this idiosyncratic variability, we recommend that researchers more transparently share details of their analysis, strengthen the link between theoretical construct and quantitative system and calibrate their (un)certainty in their conclusions

Assessment of intensive care unit-acquired weakness in young and old mice: An E. coli septic peritonitis model

There are few reports of in vivo muscle strength measurements in animal models of ICU-acquired weakness (ICU-AW). In this study we investigated whether the Escherichia coli (E. coli) septic peritonitis mouse model may serve as an ICU-AW model using in vivo strength measurements and myosin/actin assays, and whether development of ICU-AW is age-dependent in this model. Young and old mice were injected intraperitoneally with E. coli and treated with ceftriaxone. Forelimb grip strength was measured at multiple time points, and the myosin/actin ratio in muscle was determined. E. coli administration was not associated with grip strength decrease, neither in young nor in old mice. In old mice, the myosin/actin ratio was lower in E. coli mice at t = 48 h and higher at t = 72 h compared with controls. This E. coli septic peritonitis mouse model did not induce decreased grip strength. In its current form, it seems unsuitable as a model for ICU-A

Lumbar puncture patient video increases knowledge and reduces uncertainty: An RCT

Background: Patients often perceive a lumbar puncture (LP) as an invasive procedure. We aimed to evaluate the impact of a 3-minute educational animation-video explaining the LP procedure, on patients’ knowledge, uncertainty, anxiety, and post-LP complications. Methods: We included 203 newly referred memory clinic patients, who were randomly assigned to one of three conditions: (1) home viewing of the video, (2) clinic viewing of the video, or (3) control condition (care as usual). Participants completed questionnaires measuring knowledge as information recall, uncertainty, anxiety, and post-LP complications, the latter when patients underwent an LP procedure (n = 145). Results: Viewing the video increased information recall for both home (P <.001), and clinic viewers (P <.001) compared to controls. Levels of uncertainty decreased after viewing (Pfor interaction=.044), particularly for clinic viewers. Viewing the video or not did not affect anxiety and post-LP complications. Discussion: Preparing individuals for an LP by means of an educational video can help to increase knowledge about the procedure and reduce feelings of uncertainty

Lumbar puncture patient video increases knowledge and reduces uncertainty: An RCT

Background: Patients often perceive a lumbar puncture (LP) as an invasive procedure. We aimed to evaluate the impact of a 3-minute educational animation-video explaining the LP procedure, on patients’ knowledge, uncertainty, anxiety, and post-LP complications. Methods: We included 203 newly referred memory clinic patients, who were randomly assigned to one of three conditions: (1) home viewing of the video, (2) clinic viewing of the video, or (3) control condition (care as usual). Participants completed questionnaires measuring knowledge as information recall, uncertainty, anxiety, and post-LP complications, the latter when patients underwent an LP procedure (n = 145). Results: Viewing the video increased information recall for both home (P <.001), and clinic viewers (P <.001) compared to controls. Levels of uncertainty decreased after viewing (Pfor interaction=.044), particularly for clinic viewers. Viewing the video or not did not affect anxiety and post-LP complications. Discussion: Preparing individuals for an LP by means of an educational video can help to increase knowledge about the procedure and reduce feelings of uncertainty