Viscoelastic haemostatic assay augmented protocols for major trauma haemorrhage (ITACTIC): a randomized, controlled trial.

PURPOSE: Contemporary trauma resuscitation prioritizes control of bleeding and uses major haemorrhage protocols (MHPs) to prevent and treat coagulopathy. We aimed to determine whether augmenting MHPs with Viscoelastic Haemostatic Assays (VHA) would improve outcomes compared to Conventional Coagulation Tests (CCTs). METHODS: This was a multi-centre, randomized controlled trial comparing outcomes in trauma patients who received empiric MHPs, augmented by either VHA or CCT-guided interventions. Primary outcome was the proportion of subjects who, at 24 h after injury, were alive and free of massive transfusion (10 or more red cell transfusions). Secondary outcomes included 28-day mortality. Pre-specified subgroups included patients with severe traumatic brain injury (TBI). RESULTS: Of 396 patients in the intention to treat analysis, 201 were allocated to VHA and 195 to CCT-guided therapy. At 24 h, there was no difference in the proportion of patients who were alive and free of massive transfusion (VHA: 67%, CCT: 64%, OR 1.15, 95% CI 0.76-1.73). 28-day mortality was not different overall (VHA: 25%, CCT: 28%, OR 0.84, 95% CI 0.54-1.31), nor were there differences in other secondary outcomes or serious adverse events. In pre-specified subgroups, there were no differences in primary outcomes. In the pre-specified subgroup of 74 patients with TBI, 64% were alive and free of massive transfusion at 24 h compared to 46% in the CCT arm (OR 2.12, 95% CI 0.84-5.34). CONCLUSION: There was no difference in overall outcomes between VHA- and CCT-augmented-major haemorrhage protocols.

Combined effect of therapeutic strategies for bleeding injury on early survival, transfusion needs and correction of coagulopathy.

BACKGROUND: The combined effects of balanced transfusion ratios and use of procoagulant and antifibrinolytic therapies on trauma-induced exsanguination are not known. The aim of this study was to investigate the combined effect of transfusion ratios, tranexamic acid and products containing fibrinogen on the outcome of injured patients with bleeding. METHODS: A prospective multicentre observational study was performed in six level 1 trauma centres. Injured patients who received at least 4 units of red blood cells (RBCs) were analysed and divided into groups receiving a low (less than 1 : 1) or high (1 or more : 1) ratio of plasma or platelets to RBCs, and in receipt or not of tranexamic acid or fibrinogen products (fibrinogen concentrates or cryoprecipitate). Logistic regression models were used to assess the effect of transfusion strategies on the outcomes 'alive and free from massive transfusion' (at least 10 units of RBCs in 24 h) and early 'normalization of coagulopathy' (defined as an international normalized ratio of 1·2 or less). RESULTS: A total of 385 injured patients with ongoing bleeding were included in the study. Strategies that were independently associated with an increased number of patients alive and without massive transfusion were a high platelet to RBC ratio (odds ratio (OR) 2·67, 95 per cent c.i. 1·24 to 5·77; P = 0·012), a high plasma to RBC ratio (OR 2·07, 1·03 to 4·13; P = 0·040) and treatment with tranexamic acid (OR 2·71, 1·29 to 5·71; P = 0·009). No strategies were associated with correction of coagulopathy. CONCLUSION: A high platelet or plasma to RBC ratio, and use of tranexamic acid were associated with a decreased need for massive transfusion and increased survival in injured patients with bleeding. Early normalization of coagulopathy was not seen for any transfusion ratio, or for use of tranexamic acid or fibrinogen products.

Mortality from trauma haemorrhage and opportunities for improvement in transfusion practice.

BACKGROUND: The aim of this study was to describe the prevalence, patterns of blood use and outcomes of major haemorrhage in trauma. METHODS: This was a prospective observational study from 22 hospitals in the UK, including both major trauma centres and smaller trauma units. Eligible patients received at least 4 units of packed red blood cells (PRBCs) in the first 24 h of admission with activation of the massive haemorrhage protocol. Case notes, transfusion charts, blood bank records and copies of prescription/theatre charts were accessed and reviewed centrally. Study outcomes were: use of blood components, critical care during hospital stay, and mortality at 24 h, 30 days and 1 year. Data were used to estimate the national trauma haemorrhage incidence. RESULTS: A total of 442 patients were identified during a median enrolment interval of 20 (range 7-24) months. Based on this, the national incidence of trauma haemorrhage was estimated to be 83 per million. The median age of patients in the study cohort was 38 years and 73·8 per cent were men. The incidence of major haemorrhage increased markedly in patients aged over 65 years. Thirty-six deaths within 24 h of admission occurred within the first 3 h. At 24 h, 79 patients (17·9 per cent) had died, but mortality continued to rise even after discharge. Patients who received a cumulative ratio of fresh frozen plasma to PRBCs of at least 1 : 2 had lower rates of death than those who received a lower ratio. There were delays in administration of blood. Platelets and cryoprecipitate were either not given, or transfused well after initial resuscitation. CONCLUSION: There is a high burden of trauma haemorrhage that affects all age groups. Research is required to understand the reasons for death after the first 24 h and barriers to timely transfusion support.

Guanidine hydrochloride blocks a critical step in the propagation of the prion-like determinant [PSI(+)] of Saccharomyces cerevisiae.

The cytoplasmic heritable determinant [PSI(+)] of the yeast Saccharomyces cerevisiae reflects the prion-like properties of the chromosome-encoded protein Sup35p. This protein is known to be an essential eukaryote polypeptide release factor, namely eRF3. In a [PSI(+)] background, the prion conformer of Sup35p forms large oligomers, which results in the intracellular depletion of functional release factor and hence inefficient translation termination. We have investigated the process by which the [PSI(+)] determinant can be efficiently eliminated from strains, by growth in the presence of the protein denaturant guanidine hydrochloride (GuHCl). Strains are "cured" of [PSI(+)] by millimolar concentrations of GuHCl, well below that normally required for protein denaturation. Here we provide evidence indicating that the elimination of the [PSI(+)] determinant is not derived from the direct dissolution of self-replicating [PSI(+)] seeds by GuHCl. Although GuHCl does elicit a moderate stress response, the elimination of [PSI(+)] is not enhanced by stress, and furthermore, exhibits an absolute requirement for continued cell division. We propose that GuHCl inhibits a critical event in the propagation of the prion conformer and demonstrate that the kinetics of curing by GuHCl fit a random segregation model whereby the heritable [PSI(+)] element is diluted from a culture, after the total inhibition of prion replication by GuHCl.

Translation termination efficiency can be regulated in Saccharomyces cerevisiae by environmental stress through a prion-mediated mechanism.

[PSI+] is a protein-based heritable phenotype of the yeast Saccharomyces cerevisiae which reflects the prion-like behaviour of the endogenous Sup35p protein release factor. [PSI+] strains exhibit a marked decrease in translation termination efficiency, which permits decoding of translation termination signals and, presumably, the production of abnormally extended polypeptides. We have examined whether the [PSI+]-induced expression of such an altered proteome might confer some selective growth advantage over [psi-] strains. Although otherwise isogenic [PSI+] and [psi-] strains show no difference in growth rates under normal laboratory conditions, we demonstrate that [PSI+] strains do exhibit enhanced tolerance to heat and chemical stress, compared with [psi-] strains. Moreover, we also show that the prion-like determinant [PSI+] is able to regulate translation termination efficiency in response to environmental stress, since growth in the presence of ethanol results in a transient increase in the efficiency of translation termination and a loss of the [PSI+] phenotype. We present a model to describe the prion-mediated regulation of translation termination efficiency and discuss its implications in relation to the potential physiological role of prions in S.cerevisiae and other fungi.

Potent immunogenicity of the B subunits of Escherichia coli heat-labile enterotoxin: receptor binding is essential and induces differential modulation of lymphocyte subsets.

The importance of receptor binding in the potent immunogenicity of Escherichia coli heat-labile enterotoxin B subunit (EtxB) was tested by comparing its immunogical properties with those of a receptor binding mutant, EtxB(G33D). Subcutaneous immunization of EtxB(G33D) resulted in 160-fold reduction in antibody titer compared with wild-type EtxB, whereas its oral delivery failed to provoke any detectable secretory or serum anti-B subunit responses. Moreover, the two proteins induced strikingly different effects on lymphocyte cultures in vitro. EtxB, in comparison with EtxB(G33D), caused an increase in the proportion of B cells, many of which were activated (CD25+); the complete depletion of CD8+ T cells; an increase in the activation of CD4+ T cells; and an increase in interleukin 2 and a decrease in interferon gamma. These data indicate that EtxB exerts profound effects on immune cells, suggesting that its potent immunogenicity is dependent not only on efficient receptor-mediated uptake, but also on direct receptor-mediated immunomodulation of lymphocyte subsets.