A comparative study of tissue factor and kaolin on blood coagulation assays using rotational thromboelastometry and thromboelastography.

Rotational thromboelastometry (ROTEM) and thromboelastography (TEG) have been increasingly used to diagnose acute coagulopathy and guide blood transfusion. The tests are routinely performed using different triggering activators such as tissue factor and kaolin, which activate different pathways yielding different results. To optimize the global blood coagulation assays using ROTEM and TEG, we conducted a comparative study on the activation methods employing tissue factor and kaolin at different concentrations as well as standard reagents as recommended by the manufacturer of each device.

Theta, mental flexibility, and post-traumatic stress disorder: connecting in the parietal cortex.

Post-traumatic stress disorder (PTSD) is a mental health injury characterised by re-experiencing, avoidance, numbing and hyperarousal. Whilst the aetiology of the disorder is relatively well understood, there is debate about the prevalence of cognitive sequelae that manifest in PTSD. In particular, there are conflicting reports about deficits in executive function and mental flexibility.

Delayed and disorganised brain activation detected with magnetoencephalography after mild traumatic brain injury.

Background: Awareness to neurocognitive issues after mild traumatic brain injury (mTBI) is increasing, but currently no imaging markers are available for mTBI. Advanced structural imaging recently showed microstructural tissue changes and axonal injury, mild but likely sufficient to lead to functional deficits. Magnetoencephalography (MEG) has high temporal and spatial resolution, combining structural and electrophysiological information, and can be used to examine brain activation patterns of regions involved with specific tasks.

Temporal-spatial neural activation patterns linked to perceptual encoding of emotional salience.

It is well known that we continuously filter incoming sensory information, selectively allocating attention to what is important while suppressing distracting or irrelevant information. Yet questions remain about spatiotemporal patterns of neural processes underlying attentional biases toward emotionally significant aspects of the world. One index of affectively biased attention is an emotional variant of an attentional blink (AB) paradigm, which reveals enhanced perceptual encoding for emotionally salient over neutral stimuli under conditions of limited executive attention.

Prehospital hypertonic saline resuscitation attenuates the activation and promotes apoptosis of neutrophils in patients with severe traumatic brain injury.

Background: Activation of polymorphonuclear neutrophils (PMNs) is thought to contribute to traumatic brain injury (TBI). Since hypertonic fluids can inhibit PMN activation, we studied whether hypertonic fluid resuscitation can reduce excessive PMN activation in TBI patients.

Methods: Trauma patients with severe TBI were resuscitated with 250 mL of either 7.

Resuscitation of traumatic hemorrhagic shock patients with hypertonic saline-without dextran-inhibits neutrophil and endothelial cell activation.

Posttraumatic inflammation and excessive neutrophil activation cause multiple organ dysfunction syndrome (MODS), a major cause of death among hemorrhagic shock patients. Traditional resuscitation strategies may exacerbate inflammation; thus, novel fluid treatments are needed to reduce such posttraumatic complications. Hypertonic resuscitation fluids inhibit inflammation and reduce MODS in animal models.

Surface-attached amphipathic peptides reduce hemorrhage in vivo.

Background: The leading causes of death for trauma patients in civilian and combat settings are traumatic brain injury and uncontrolled hemorrhage, respectively. This study examines the hemostatic activity of an ideal amphipathic peptide (IAP) attached to a biocompatible surface.

Methods: Procoagulant properties of IAP attached to a surface were first tested, in vitro, using factor Xa and thrombin generation assays and thromboelastography.

Characterization of in vitro hemostatic peptide effects by thromboelastography.

In this study, we validated a thromboelastography (TEG) method to evaluate the hemostatic effects of 3 peptides. The first peptide is an ideal amphipathic peptide composed of 22 leucine and lysine in a ratio of 2:1. At a very low concentration, the peptide had a procoagulant effect shown by decreases in reaction time (R) and coagulation time (K) but was impaired by a decrease in maximum amplitude (MA).

A model of low-level primary blast brain trauma results in cytoskeletal proteolysis and chronic functional impairment in the absence of lung barotrauma.

Shock-wave exposure from improvised explosive devices (IEDs) has been implicated as a possible contributing factor to neurological impairment reported in combat veterans. However, evidence-based substantiation of this implication, particularly for low-level exposure in the absence of external signs of trauma, remain elusive. Accordingly, we constructed an open-ended shock tube producing a short-duration, low-amplitude shockwave.

Novel wound sealants: biomaterials and applications.

Wound sealants provide an excellent alternative for closing surgical and non-surgical wounds, as well as stopping external bleeding for prehospital trauma injuries. Numerous biomaterials have been investigated to address specific requirements for their use as suitable wound sealants. This article focuses on the development of new wound sealant biomaterials and recent advances in the surgical applications of wound sealants.

Prehospital resuscitation with hypertonic saline-dextran modulates inflammatory, coagulation and endothelial activation marker profiles in severe traumatic brain injured patients.

Background: Traumatic brain injury (TBI) initiates interrelated inflammatory and coagulation cascades characterized by wide-spread cellular activation, induction of leukocyte and endothelial cell adhesion molecules and release of soluble pro/antiinflammatory cytokines and thrombotic mediators. Resuscitative care is focused on optimizing cerebral perfusion and reducing secondary injury processes. Hypertonic saline is an effective osmotherapeutic agent for the treatment of intracranial hypertension and has immunomodulatory properties that may confer neuroprotection.

Abnormal coagulation tests are associated with progression of traumatic intracranial hemorrhage.

Background: Intracranial hemorrhage (ICH) is common in traumatic brain injury (TBI) and a major determinant of death and disability. ICH commonly increases in size and coagulopathy has been implicated in such progression. We investigated the association between coagulopathy diagnosed by routine laboratory tests and ICH progression.

Resuscitation with hypertonic saline-dextran reduces serum biomarker levels and correlates with outcome in severe traumatic brain injury patients.

In the treatment of severe traumatic brain injury (TBI), the choice of fluid and osmotherapy is important. There are practical and theoretical advantages to the use of hypertonic saline. S100B, neuron-specific enolase (NSE), and myelin-basic protein (MBP) are commonly assessed biomarkers of brain injury with potential utility as diagnostic and prognostic indicators of outcome after TBI, but they have not previously been studied in the context of fluid resuscitation.

Development of in situ-forming hydrogels for hemorrhage control.

We report the preparation of in situ-forming hydrogels, composed of oxidized dextran (Odex) and amine-containing polymers, for their potential use as a wound dressing to promote blood clotting. Dextran was oxidized by sodium periodate to introduce aldehyde groups to form hydrogels, upon mixing in solution with different polymers containing primary amine groups, including polyallylamine (PAA), oligochitosan and glycol chitosan. A series of experiments were conducted to identify the optimum gelation condition for the Odex-PAA system.

Synthesis and characterization of a novel in situ forming gel based on hydrogel dispersions.

This report describes the synthesis and characterization of hydrogel dispersions for the potential use as an in situ gel-forming wound sealant. A series of polyacrylamide (PAAm) particles (solid content 5-10 wt %) were prepared by dispersion polymerization of acrylamide (AAm) in a solvent mixture of ethanol/water (90/10 w/w). These particles are characterized by the presence of a "core" [ethylene glycol dimethacrylate (EGDMA) crosslinked PAAm] surrounded by a "shell" [acetoacetoxyethyl methacrylate (AAEMA) or 2-aminoethylmethacrylate-containing PAAm, named as AAEMA-xPAAm and NH(2)-xPAAm, respectively; x represents "crosslinked"].

Experimental optimization of an in situ forming hydrogel for hemorrhage control.

The fabrication of a novel in situ forming hydrogel composed of a multifunctional poly(ethylene glycol) (PEG) N-hydroxysuccinimide ester (NHS) and poly(allylamine hydrochloride) (PAA) was investigated. FTIR confirmed that PAA formed the hydrogel matrix (i.e.

Characterization of an ideal amphipathic peptide as a procoagulant agent.

On the basis of previous evidence that amphipathic helical peptides accelerate Factor IXa activation of Factor X [Blostein, Rigby, Furie, Furie and Gilbert (2000) Biochemistry 39, 12000-12006], the present study was designed to assess the procoagulant activity of an IAP (ideal amphipathic peptide) of Lys(7)Leu(15) composition. The results show that IAP accelerates Factor X activation by Factor IXa in a concentration-dependent manner and accelerates thrombin generation by Factor Xa with a comparable peptide- and substrate-concentration-dependence. A scrambled helical peptide with the same amino acid composition as IAP, but with its amphipathicity abolished, eliminated most of the aforementioned effects.

Hydrogel-elastomer composite biomaterials: 3. Effects of gelatin molecular weight and type on the preparation and physical properties of interpenetrating polymer networks.

To optimize the preparation of a gelatin-HydroThane Interpenetrating Polymer Network (IPN) and obtain optimum physical properties for its use as a wound dressing, we studied IPN films prepared with two types of gelatin having different molecular weights. The effects of the gelatin molecular weight and type on the IPN film's structure, morphology, swelling and mechanical properties were determined. While FTIR did not reveal any noticeable differences between the IPNs prepared using different gelatin, light microscopy showed a lesser phase separation of the film prepared with a high-molecular-weight type A gelatin.

Hydrogel-elastomer composite biomaterials: 2. Effects of aging methacrylated gelatin solutions on the preparation and physical properties of interpenetrating polymer networks.

This study was conducted to understand the effects of aging methacrylated gelatin solutions on the properties of gelatin-HydroThane Interpenetrating Polymer Network (IPN) films. The latter were prepared from methacrylated gelatin solutions that were either freshly made or stored at different concentrations and temperatures for various periods. The morphology, swelling stability and mechanical properties of the IPNs were then accordingly characterized.

Hydrogel-elastomer composite biomaterials: 1. Preparation of interpenetrating polymer networks and in vitro characterization of swelling stability and mechanical properties.

We prepared interpenetrating polymer networks (IPNs) composed of a gelatin hydrogel and a HydroThane elastomer to combine the advantages of both polymers into one biomaterial. Fourier transform Infrared (FTIR) spectroscopy and Differential Scanning Calorimetry (DSC) confirmed the co-existence of the two polymers in the IPNs. Optical light microscopy confirmed hydrogel domains were interspaced into an elastomer network.

Ocular hypotensive effects of an intratracheally delivered liposomal delta9-tetrahydrocannabinol preparation in rats.

This study investigated the effect of an intratracheal (i.t.) administration of a liposome-entrapped Delta9-tetrahydrocannabinol (LTHC) preparation on intraocular pressure (IOP) in nonanaesthetized Brown Norway rats.

Evaluation of a bi-layer wound dressing for burn care. II. In vitro and in vivo bactericidal properties.

We have recently designed a medicated bi-layer wound dressing to address the key requirements for treating external, contaminated war wounds. This study assessed the in vitro and in vivo bactericidal efficacies of the DRDC hydrogel/polyurethane wound dressing. Chloramphenicol- and chlorhexidine-loaded DRDC dressings produced significantly larger zones of inhibition against Pseudomonas aeruginosa than the other medicated dressings for 4 d.

Evaluation of a bi-layer wound dressing for burn care I. Cooling and wound healing properties.

Severe burns remain a significant cause of morbidity and mortality despite the availability of numerous therapies. We assessed the wound healing and skin-cooling properties of a DRDC hydrogel/polyurethane wound dressing using different pre-clinical models. Our results show that 85% of partial-thickness, non-contaminated porcine wounds treated with our dressing healed within 6 days.

The immunomodulatory effects of hypertonic saline resuscitation in patients sustaining traumatic hemorrhagic shock: a randomized, controlled, double-blinded trial.

Objective: To investigate the potential immunologic and anti-inflammatory effects of hypertonic saline plus dextran (HSD) in hemorrhagic trauma patients.

Background: Unbalanced inflammation triggered by shock has been linked to multiorgan dysfunction (MOD) and death. In animal and cellular models, HSD alters the inflammatory response to shock, attenuating MOD and improving outcome.

Natural killer cell lytic activity and CD56(dim) and CD56(bright) cell distributions during and after intensive training.

The purpose of this study was to examine the impact of intensive training for competitive sports on natural killer (NK) cell lytic activity and subset distribution. Eight female college-level volleyball players undertook 1 mo of heavy preseason training. Volleyball drills were performed 5 h/day, 6 days/wk.