P23 Investigating synaptopathy following traumatic brain injury in a preclinical model

Objectives

The impact of Traumatic Brain Injury (TBI) on the synapse is poorly understood. We examined the impact of TBI on the distribution of two postsynaptic density proteins (PSD95 and SAP102) at single-synapse resolution.

Subjects

44 male transgenic knock-in mice, aged 8–16 weeks, expressing fluorescently labelled PSD95 and SAP102.

Methods

Mice were randomised to a mild lateral fluid percussion injury (LFPI) or sham treatment and brain sections were examined at 7 and 28 days. Using high resolution confocal microscopy and machine learning algorithms, the synaptic puncta density, size and intensity were mapped across 222 brain regions. Microglia and presynaptic changes were indexed using Iba1 and SV2A immunostaining. Pearson correlation and t-tests were used (significance p<0.05).

Results

We found a significant reduction in synaptic puncta density at 28 days post-injury in brain regions distal to the injury site including the hippocampus. PSD95 and SAP102 density changes had a strong positive correlation at 28 days (r=0.8; p<0.0001). We also observed evidence of synapse recovery in the ipsilateral cortex between 7 and 28 days. Puncta density had a positive correlation with SV2A (r=0.7; p<0.01) and a negative correlation with (r=−0.6; p<0.001) Iba1 count.

Conclusions

Focal LFPI induced progressive region-specific loss of synapses for which microglia may play a role. Our study highlights the value of brain-wide synaptome mapping technology and suggests a capacity for synaptic recovery which could be a therapeutic target.

Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part I

Flame retardants (FRs) are added to foams and plastics to comply with flammability standards and test requirements in products for household and industrial uses. When these regulations were implemented, potential health and environmental impacts of FR use were not fully recognized or understood. Extensive research in the past decades reveal that exposure to halogenated FRs, such as those used widely in furniture foam, is associated with and/or causally related to numerous health effects in animals and humans. While many of the toxic FRs have been eliminated and replaced by other FRs, existing products containing toxic or potentially toxic chemical FRs will remain in use for decades, and new products containing these and similar chemicals will permeate the environment. When such products reach the end of their useful life, proper disposal methods are needed to avoid health and ecological risks. To minimize continued human and environmental exposures to hazardous FR chemicals from discarded products, waste management technologies and processes must be improved. This review discusses a wide range of issues associated with all aspects of the use and responsible disposal of wastes containing FRs, and identifies basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes.

Methods of Responsibly Managing End-of-Life Foams and Plastics Containing Flame Retardants: Part II

This is Part II of a review covering the wide range of issues associated with all aspects of the use and responsible disposal of foam and plastic wastes containing toxic or potentially toxic flame retardants. We identify basic and applied research needs in the areas of responsible collection, pretreatment, processing, and management of these wastes. In Part II, we explore alternative technologies for the management of halogenated flame retardant (HFR) containing wastes, including chemical, mechanical, and thermal processes for recycling, treatment, and disposal.

Publisher Correction: BRD4 interacts with NIPBL and BRD4 is mutated in a Cornelia de Lange-like syndrome

In the version of this article initially published, Wendy Bickmore and Madapura Pradeepa were incorrectly not indicated as corresponding authors. The error has been corrected in the HTML and PDF versions of the paper.

Scc2/Nipbl hops between chromosomal cohesin rings after loading

The cohesin complex mediates DNA-DNA interactions both between (sister chromatid cohesion) and within chromosomes (DNA looping). It has been suggested that intra-chromosome loops are generated by extrusion of DNAs through the lumen of cohesin's ring. Scc2 (Nipbl) stimulates cohesin's ABC-like ATPase and is essential for loading cohesin onto chromosomes. However, it is possible that the stimulation of cohesin's ATPase by Scc2 also has a post-loading function, for example driving loop extrusion. Using fluorescence recovery after photobleaching (FRAP) and single-molecule tracking in human cells, we show that Scc2 binds dynamically to chromatin, principally through an association with cohesin. Scc2's movement within chromatin is consistent with a 'stop-and-go' or 'hopping' motion. We suggest that a low diffusion coefficient, a low stoichiometry relative to cohesin, and a high affinity for chromosomal cohesin enables Scc2 to move rapidly from one chromosomal cohesin complex to another, performing a function distinct from loading.

Protocol for meta-analysis of temperature reduction in animal models of cardiac arrest

Targeted temperature management (TTM) of 32–34 °C has been the standard treatment for out‐of‐hospital cardiac arrest since clinical trials in 2002 showed benefits to survival and neurological outcome. Recently, this treatment has been challenged by another clinical trial showing no difference in outcome between TTM of 33 °C and 36 °C. This protocol describes the methodology for a meta‐analysis detailing temperature‐reducing interventions to treat global ischaemia in animal models. By combining relevant data sets in the literature, we will explore the experimental evidence for TTM. Our aims are to explain possible translational gaps and provide methodological considerations for future experimental research and clinical trials.

Individualized Internal and External Training Load Relationships in Elite Wheelchair Rugby Players

Aim: The quantification and longitudinal monitoring of athlete training load (TL) provides a scientific explanation for changes in performance and helps manage injury/illness risk. Therefore, accurate and reliable monitoring tools are essential for the optimization of athletic performance. The aim of the present study was to establish the relationship between measures of internal [heart rate (HR) and session RPE (sRPE)] and external TL specific to wheelchair rugby (WR).

Methods: Fourteen international WR athletes (age = 29 ± 7 years; body mass = 58.9 ± 10.9 kg) were monitored during 18 training sessions over a 3 month period during the competitive phase of the season. Activity profiles were collected during each training session using a radio-frequency based indoor tracking system (ITS). External TL was quantified by total distance (m) covered as well as time spent and distance covered in a range of classification-specific arbitrary speed zones. Banister's TRIMP, Edwards's summated HR zone (SHRZ), and Lucia's TRIMP methods were used to quantify physiological internal TL. sRPE was calculated as the product of session duration multiplied by perceived exertion using the Borg CR10 scale. Relationships between external and internal TL were examined using correlation coefficients and the 90% confidence intervals (90% CI).

Results: sRPE (r = 0.59) and all HR-based (r > 0.80) methods showed large and very large relationships with the total distance covered during training sessions, respectively. Large and very large correlations (r = 0.56 − 0.82) were also observed between all measures of internal TL and times spent and distances covered in low and moderate intensity speed zones. HR-based methods showed very large relationships with time (r = 0.71−0.75) and distance (r = 0.70−0.73) in the very high speed zone and a large relationship with the number of high intensity activities (HIA) performed (r = 0.56−0.62). Weaker relationships (r = 0.32−0.35) were observed between sRPE and all measures of high intensity activity. A large variation of individual correlation co-efficient was observed between sRPE and all external TL measures.

Conclusion: The current findings suggest that sRPE and HR-based internal TL measures provide a valid tool for quantifying volume of external TL during WR training but may underestimate HIA. It is recommended that both internal and external TL measures are employed for the monitoring of overall TL during court-based training in elite WR athletes.

3D osteoarthritic changes in TMJ condylar morphology correlates with specific systemic and local biomarkers of disease

OBJECTIVE

To assess 3D morphological variations and local and systemic biomarker profiles in subjects with a diagnosis of temporomandibular joint osteoarthritis (TMJ OA).

DESIGN

Twenty-eight patients with long-term TMJ OA (39.9 ± 16 years), 12 patients at initial diagnosis of OA (47.4 ± 16.1 years), and 12 healthy controls (41.8 ± 12.2 years) were recruited. All patients were female and had cone beam CT scans taken. TMJ arthrocentesis and venipuncture were performed on 12 OA and 12 age-matched healthy controls. Serum and synovial fluid levels of 50 biomarkers of arthritic inflammation were quantified by protein microarrays. Shape Analysis MANCOVA tested statistical correlations between biomarker levels and variations in condylar morphology.

RESULTS

Compared with healthy controls, the OA average condyle was significantly smaller in all dimensions except its anterior surface, with areas indicative of bone resorption along the articular surface, particularly in the lateral pole. Synovial fluid levels of ANG, GDF15, TIMP-1, CXCL16, MMP-3 and MMP-7 were significantly correlated with bone apposition of the condylar anterior surface. Serum levels of ENA-78, MMP-3, PAI-1, VE-Cadherin, VEGF, GM-CSF, TGFβb1, IFNγg, TNFαa, IL-1αa, and IL-6 were significantly correlated with flattening of the lateral pole. Expression levels of ANG were significantly correlated with the articular morphology in healthy controls.

CONCLUSIONS

Bone resorption at the articular surface, particularly at the lateral pole was statistically significant at initial diagnosis of TMJ OA. Synovial fluid levels of ANG, GDF15, TIMP-1, CXCL16, MMP-3 and MMP-7 were correlated with bone apposition. Serum levels of ENA-78, MMP-3, PAI-1, VE-Cadherin, VEGF, GM-CSF, TGFβ1, IFNγ, TNFα, IL-1α, and IL-6 were correlated with bone resorption.

The validity and reliability of a novel indoor player tracking system for use within wheelchair court sports

The aim of the current study was to investigate the validity and reliability of a radio frequency-based system for accurately tracking athlete movement within wheelchair court sports. Four wheelchair-specific tests were devised to assess the system during (i) static measurements; (ii) incremental fixed speeds; (iii) peak speeds; and (iv) multidirectional movements. During each test, three sampling frequencies (4, 8 and 16 Hz) were compared to a criterion method for distance, mean and peak speeds. Absolute static error remained between 0.19 and 0.32 m across the session. Distance values (test (ii)) showed greatest relative error in 4 Hz tags (1.3%), with significantly lower errors seen in higher frequency tags (<1.0%). Relative peak speed errors of <2.0% (test (iii)) were revealed across all sampling frequencies in relation to the criterion (4.00 ± 0.09 m · s-(1)). Results showed 8 and 16 Hz sampling frequencies displayed the closest-to-criterion values, whilst intra-tag reliability never exceeded 2.0% coefficient of variation (% CV) during peak speed detection. Minimal relative distance errors (<0.2%) were also seen across sampling frequencies (test (iv)). To conclude, the indoor tracking system is deemed an acceptable tool for tracking wheelchair court match play using a tag frequency of 8 or 16 Hz.

Pilot-scale data provide enhanced estimates of the life cycle energy and emissions profile of algae biofuels produced via hydrothermal liquefaction

Life cycle assessment (LCA) has been used widely to estimate the environmental implications of deploying algae-to-energy systems even though no full-scale facilities have yet to be built. Here, data from a pilot-scale facility using hydrothermal liquefaction (HTL) is used to estimate the life cycle profiles at full scale. Three scenarios (lab-, pilot-, and full-scale) were defined to understand how development in the industry could impact its life cycle burdens. HTL-derived algae fuels were found to have lower greenhouse gas (GHG) emissions than petroleum fuels. Algae-derived gasoline had significantly lower GHG emissions than corn ethanol. Most algae-based fuels have an energy return on investment between 1 and 3, which is lower than petroleum biofuels. Sensitivity analyses reveal several areas in which improvements by algae bioenergy companies (e.g., biocrude yields, nutrient recycle) and by supporting industries (e.g., CO2 supply chains) could reduce the burdens of the industry.

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CD4+ T lymphocytes, which orchestrate immune responses, receive a cognitive signal when clonally distributed receptors are occupied by peptides bound to major histocompatibility complex (MHC) class II molecules on antigen-presenting cells. The latter cells provide costimulatory or accessory signals through macromolecules such as B7.1 and B7.2, which interact with coreceptors on T cells to regulate outcomes in terms of T cell activation or specific nonresponsiveness. Complementary studies of the interactions between antigen-presenting cells and T helper cells at the chemical level have implicated Schiff base formation between specialised carbonyls and amines, constitutively expressed on the surfaces of antigen-presenting cells and T cells, as an essential element in specific T cell activation. Small Schiff base-forming molecules can substitute for the natural donor of carbonyl groups and provide a costimulatory signal to the T cell. From this class of Schiff base-forming costimulatory molecules, the small xenobiotic substituted benzaldehyde, tucaresol, has been selected for development and testing as an immunopotentiatory drug. Tucaresol, which is orally bioavailable and systemically active, enhances CD4+ T helper cell and CD8+ cytotoxic T cell responses in vivo, and selectively favours a T helper 1 profile of cytokine production. In murine models of virus infection and syngeneic tumour growth it has substantial therapeutic activity. Schiff base formation by tucaresol on T cell surface amines provides a costimulatory signal to the T cell through a mechanism that activates clofilium-sensitive K(+) and Na(+) transport. The pathway utilised by tucaresol converges with T cell receptor signalling at the level of mitogen-activated protein (MAP) kinase, promoting the activation of MAP kinase kinase (MEK) and consequential tyrosyl phosphorylation of ERK2. Tucaresol is the first orally active, mechanism-based immunopotentiatory drug available for therapeutic testing. It is currently undergoing phase I/II clinical trials in chronic hepatitis B virus infection, HIV infection and malignant melanoma.