Dismounted Complex Blast Injuries Including Invasive Fungal Infections.

Large blast injuries during dismounted operations in southwest Afghanistan causing major limb amputations and perineal injuries associated with large blood volume resuscitation were associated with invasive fungal, primarily mold, infections. This article outlines the interventions undertaken to mitigate excess morbidity and mortality associated with invasive fungal infection. These interventions include defining the problem and associated risk with systemically collected and analyzed information, developing improved protective body armor for the thigh and perineal region, standardizing management through clinical practice guidelines that outlined risk, diagnostic and treatment recommendations with enhanced discussions on the weekly Theater Combat Casualty Care Conference that includes personnel from the combat zone, Germany, and the United States. The article concludes by explaining the key way forward with regarding an inner-war approach to sustained knowledge and skills.

Replacement of Promethazine With Ondansetron for Treatment of Opioid- and Trauma-Related Nausea and Vomiting in Tactical Combat Casualty Care.

The current Tactical Combat Casualty Care (TCCC) Guidelines recommend parenteral promethazine as the single agent for the treatment of opioid-induced nausea and/or vomiting and give a secondary indication of "synergistic analgesic effect." Promethazine, however, has a well-documented history of undesired side effects relating to impairment and dysregulation of the central and autonomic nervous systems, such as sedation, extrapyramidal symptoms, dystonia, impairment of psychomotor function, neuroleptic malignant syndrome, and hypotension. These may be particularly worrisome in the combat casualty. Additionally, since 16 September 2009, there has been a US Food and Drug Administration (FDA) black box warning for the injectable form of promethazine, due to "the risk of serious tissue injury when this drug is administered incorrectly." Conversely, ondansetron, which is now available in generic form, has a well-established favorable safety profile and demonstrated efficacy in undifferentiated nausea and vomiting in the emergency department and prehospital settings. It has none of the central and autonomic nervous system side effects noted with promethazine and carries no FDA black box warning. Ondansetron is available in parenteral form and an orally disintegrating tablet, providing multiple safe and effective routes of administration. Despite the fact that it is an off-label use, ondansetron is being increasingly given for acute, undifferentiated nausea and vomiting and is presently being used in the field on combat casualties by some US and Allied Forces. Considering the risks involved with promethazine use, and the efficacy and safety of ondansetron and ondansetron?s availability in a generic form, we recommend removing promethazine from the TCCC Guidelines and replacing it with ondansetron.

Traumatic brain injury recorded in the UK Joint Theatre Trauma Registry among the UK Armed Forces.

OBJECTIVES: To use the UK Joint Theatre Trauma Registry (UK-JTTR) to identify service personnel sustaining traumatic brain injury (TBI) in recent conflicts and to examine injury characteristics, outcomes, and severity measures predictive of survival. SETTING: Operations HERRICK (Afghanistan) and TELIC (Iraq). DESIGN: The UK-JTTR records data for every UK service person either killed on operations or treated by Defence Medical Services after a trauma call, including those evacuated for inpatient care following traumatic injury. UK-JTTR data were retrospectively analyzed to identify those who sustained TBI. MAIN MEASURES: The Mayo system was used to define TBI. Glasgow Coma Scale score, injury severity score, new injury severity score, trauma injury severity score, abbreviated injury scale, and a severity characterization of trauma were used to predict survival. RESULTS: In total, 464 UK service personnel sustained TBI, representing 19% of the 2440 casualties in Afghanistan and Iraq, recorded in the UK-JTTR. Most TBI casualties had moderate-severe TBI (402, 87%). There were 181 (39%) survivors, 56% of these received neurorehabilitation. Improvised explosive devices accounted for 55% of TBIs sustained in Afghanistan and 31% of TBIs in Iraq. Logistic regression analyses were performed using the 412 cases (149 survivors: 263 fatalities) with scores on all severity measures. The best-fitting model was based on trauma injury severity score. A trauma injury severity score more than 11.13 indicates a more than 95% probability of survival. CONCLUSION: This is the first study of UK combat TBIs between 2003 and 2011. Almost 1 in 5 UK service personnel recorded in the UK-JTTR had TBI; most were moderate-severe. However, mild TBI is likely to be underrepresented in the UK-JTTR. These findings may be used to plan future rehabilitation needs, as almost half the survivors did not receive neurorehabilitation.

Predicting When to Administer Blood Products During Tactical Aeromedical Evacuation: Evaluation of a US Model.

The administration of blood products to battlefield casualties in the prehospital arena has contributed significantly to the survival of critically injured patients in Afghanistan over the past 5 years. Given as part of an established military "chain of survival," blood product administration has represented a step-change improvement in capability for both UK and US tactical aeromedical evacuation (TACEVAC) platforms. The authors explore current concepts, analyzing and exploring themes associated with early use of blood products (fresh frozen plasma [FFP] and red blood cells [RBCs]), and they compare and evaluate a US/UK study analyzing the differences and recommending future strategy. The subject matter expert (SME) consensus guidelines developed for use by the US Army Air Ambulance units commonly known as call sign "DUSTOFF." These TACEVAC assets in Afghanistan were validated in this retrospective study. Using statistical analysis, the authors were able to ascertain that the current DUSTOFF SME-derived guidelines offer a sensitivity of 63.04% and a specificity of 89.07%. By adjusting the indicators to include a single above-ankle amputation with a systolic blood pressure (SBP) less than 90 mmHg and pulse greater than 120/min, the sensitivity could be increased to 67.39% while maintaining the specificity at 89.07%. In our data set, a single amputation above the ankle, in combination with an SBP of less than 100 mmHg and a pulse of greater than 120/min, increased the sensitivity to 76% but with a slight drop in specificity to 86%. Further study of military prehospital casualty data is under way to identify additional physiological parameters that will allow simple scoring tools in the remote setting to guide the administration of prehospital blood products.

En-route care capability from point of injury impacts mortality after severe wartime injury.

OBJECTIVE: The objective of this study is to characterize modern point-of-injury (POI) en-route care platforms and to compare mortality among casualties evacuated with conventional military retrieval (CMR) methods to those evacuated with an advanced medical retrieval (AMR) capability. BACKGROUND: Following a decade of war in Afghanistan, the impact of en-route care capabilities from the POI on mortality is unknown. METHODS: Casualties evacuated from POI to one level III facility in Afghanistan (July 2008-March 2012) were identified from UK and US trauma registries. Groups comprised those evacuated by a medically qualified provider-led, AMR and those by a medic-led CMR capability. Outcomes were compared per incremental Injury Severity Score (ISS) bins. RESULTS: Most casualties (n = 1054; 61.2%) were in the low-ISS (1-15) bracket in which there was no difference in en-route care time or mortality between AMR and CMR. Casualties in the mid-ISS bracket (16-50) (n = 583; 33.4%) experienced the same median en-route care time (minutes) on AMR and CMR platforms [78 (58) vs 75 (93); P = 0.542] although those on AMR had shorter time to operation [110 (95) vs 117 (126); P < 0.001]. In this mid-ISS bracket, mortality was lower in the AMR than in the CMR group (12.2% vs 18.2%; P = 0.035). In the high-ISS category (51-75) (n = 75; 4.6%), time to operation was lower in the AMR than the CMR group (66 ± 77 vs 113 ± 122; P = 0.013) but there was no difference in mortality. CONCLUSIONS: This study characterizes en-route care capabilities from POI in modern combat. Conventional platforms are effective in most casualties with low injury severity. However, a definable injury severity exists for which evacuation with an AMR capability is associated with improved survival.

Effects of dynein on microtubule mechanics and centrosome positioning.

To determine forces on intracellular microtubules, we measured shape changes of individual microtubules following laser severing in bovine capillary endothelial cells. Surprisingly, regions near newly created minus ends increased in curvature following severing, whereas regions near new microtubule plus ends depolymerized without any observable change in shape. With dynein inhibited, regions near severed minus ends straightened rapidly following severing. These observations suggest that dynein exerts a pulling force on the microtubule that buckles the newly created minus end. Moreover, the lack of any observable straightening suggests that dynein prevents lateral motion of microtubules. To explain these results, we developed a model for intracellular microtubule mechanics that predicts the enhanced buckling at the minus end of a severed microtubule. Our results show that microtubule shapes reflect a dynamic force balance in which dynein motor and friction forces dominate elastic forces arising from bending moments. A centrosomal array of microtubules subjected to dynein pulling forces and resisted by dynein friction is predicted to center on the experimentally observed time scale, with or without the pushing forces derived from microtubule buckling at the cell periphery.

Sarcomere length fluctuations and flow in capillary endothelial cells.

Tensile force within non-muscle tissue cells is generated in actomyosin stress fibers, which are composed of contractile units called sarcomeres. The number of sarcomeres and sarcomere lengths dynamically change in the cell but the mechanisms by which these processes occur are not understood. Using live cell imaging of labeled sarcomeres, we show that sarcomere lengths continually fluctuate, with a fluctuation relaxation time of about 20 min. New sarcomeres are formed at focal adhesions and are convected into the fiber at a speed that is independent of focal adhesion size, suggesting that the speed is independent of tension. Furthermore sarcomeres were observed to disappear at specific points or "sinks" along the stress fibers. These results show that stress fibers are highly dynamic structures despite their relatively static morphology, with nascent sarcomeres forming and being incorporated into the fiber at a nearly uniform, tension-independent velocity throughout the cell. The fluctuating length of individual sarcomeres under constant tension is consistent with a model whereby sarcomere contraction/expansion speed, rather than sarcomere length, is modulated by tension.

Sarcomere mechanics in capillary endothelial cells.

Tension generation in endothelial cells of the aorta, spleen, and eye occurs in actin stress fibers, and is necessary for normal cell function. Sarcomeres are the tension-generating units of actin stress fibers in endothelial cells. How sarcomeres generate and maintain tension in stress fibers is not well understood. Using femtosecond laser ablation, we severed living stress fibers and measured sarcomere contraction under zero tension. The length of the sarcomere decreased in two phases: an instantaneous initial response, followed by a slower change in length attributed to myosin activity. The latter phase ceased abruptly after a minimum sarcomere length was reached, suggesting a rigid resistance that prevents further contraction. Furthermore, severed, contracted stress fibers did not relax when treated with myosin inhibitors, indicating that contracted stress fibers do not store elastic potential energy. These novel measurements combined with modeling suggest that myosin-generated forces in adjacent sarcomeres are directly in balance, and argue against sarcomere models with springlike elements in parallel with myosin contractile elements. We propose a new model for tension generation in the sarcomere, which provides a mechanistic interpretation for our observations and previous observations of inhomogeneous sarcomere contraction and apparent stress fiber viscoelastic behavior.

Effects of Helicobacter infection on developmental toxicity of 2,3,7,8-tetrachlorodibenzo-p-dioxin in Holtzman rats.

To obtain accurate results from experiments in animal models, all potential confounding variables must be identified and controlled. The authors examined the effects of Helicobacter infection on developmental toxicity resulting from exposure to 2,3,7,8-tetrachlorodibenzo-p-dioxin (TCDD), a persistent and ubiquitous environmental contaminant. They administered different doses of TCDD to timed pregnant Helicobacter-positive and Helicobacter-negative Holtzman rats and evaluated fetal and neonatal viability. They also assessed hepatic cytochrome P450 induction and activity of the gene Cyp1a1, which are classic indicators of TCDD exposure. All rats were affected by TCDD, and Helicobacter infection seemed to have little influence on rats' susceptibility to the compound.

Toward in situ biochemistry: combining chemical kinetics approaches with biomolecular imaging in living cells.

Our knowledge of protein-protein interactions comes primarily from experimentation with reconstituted proteins in dilute solutions. However, dilute solutions are poor approximations of the intracellular microenvironment, which contains exquisite and dynamic structure that is impossible to recreate inside test tubes. New approaches are needed that will allow the in situ characterization of protein-protein interactions inside living, intact cells. In this paper, we discuss recent efforts to measure the kinetics of protein binding within complexes inside living cells. While the experimental effort in these studies requires the confluence of techniques ranging from molecular imaging to cell and molecular biology, the experimental design and analysis requires a strong background in chemical kinetics and transport phenomena. Thus, we argue that chemical engineers can play a central role in furthering in situ approaches to cellular analysis. Such efforts may aid significantly in advancing quantitative knowledge of cellular signaling and physiology.

Characterization of a novel parainfluenza virus, caviid parainfluenza virus 3, from laboratory guinea pigs (Cavia porcellus).

A novel Respirovirus was isolated from nasopharyngeal swab specimens from clinically normal laboratory guinea pigs, and was characterized and named caviid parainfluenza virus 3 (CavPIV-3). The CavPIV-3 is enveloped, is 100 to 300 nm in diameter, and has a characteristic 15-nm-diameter chevron-shaped virus ribonucleocapsid protein. Sequence analysis of the fusion glycoprotein of CavPIV-3 revealed it to be 94% identical to human and guinea pig parainfluenza 3 (PIV-3) viruses and 80% identical to bovine PIV-3. To determine whether CavPIV-3 causes clinical disease in laboratory guinea pigs and to compare the serologic response of guinea pigs to CavPIV-3 and to other paramyxoviruses, an infection study was performed, in which groups of guinea pigs were inoculated with CavPIV-3, Sendai virus, simian virus 5 (SV-5), murine pneumonia virus (PVM), or bovine PIV-3 virus. During the course of the study, guinea pigs were maintained in an infectious disease suite, housed in Micro-Isolator cages, and were only manipulated under a laminar flow hood. Clinical signs of disease were not observed in any of the paramyxovirus-inoculated guinea pigs during the eight-week course of the study, and histologic signs of disease were not evident at necropsy eight weeks after inoculation. Guinea pigs inoculated with CavPIV-3, Sendai virus, PVM, and bovine PIV-3 developed robust homologous or heterologous serologic responses. In contrast, guinea pigs inoculated with SV-5 developed modest or equivocal serologic responses, as assessed by use of an enzyme-linked immunosorbent assay. Further, use of the SV-5 enzyme-linked immunosorbent assay resulted in the highest degree of non-specific reactivity among all of the paramyxovirus assays. In summary, CavPIV-3 is a novel guinea pig Respirovirus that subclinically infects laboratory guinea pigs, resulting in a robust serologic response, but no observed clinical or histologic disease. The CavPIV-3 fusion glycoprotein gene sequence is available from GenBank as accession No. AF394241, and the CavPIV-3 virus is available from the American Type Culture Collection as accession No. DR-1547.