Mass Casualty Scenarios Research Articles

Use of human lymphocyte G0 PCCs to detect intra- and inter-chromosomal aberrations for early radiation biodosimetry and retrospective assessment of radiation-induced effects.

A sensitive biodosimetry tool is required for rapid individualized dose estimation and risk assessment in the case of radiological or nuclear mass casualty scenarios to prioritize exposed humans for immediate medical countermeasures to reduce radiation related injuries or morbidity risks. Unlike the conventional Dicentric Chromosome Assay (DCA), which takes about 3–4 days for radiation dose estimation, cell fusion mediated Premature Chromosome Condensation (PCC) technique in G0 lymphocytes can be rapidly performed for radiation dose assessment within 6–8 hrs of sample receipt by alleviating the need for ex vivo lymphocyte proliferation for 48 hrs. Despite this advantage, the PCC technique has not yet been fully exploited for radiation biodosimetry. Realizing the advantage of G0 PCC technique that can be instantaneously applied to unstimulated lymphocytes, we evaluated the utility of G0 PCC technique in detecting ionizing radiation (IR) induced stable and unstable chromosomal aberrations for biodosimetry purposes. Our study demonstrates that PCC coupled with mFISH and mBAND techniques can efficiently detect both numerical and structural chromosome aberrations at the intra- and inter-chromosomal levels in unstimulated T- and B-lymphocytes. Collectively, we demonstrate that the G0 PCC technique has the potential for development as a biodosimetry tool for detecting unstable chromosome aberrations (chromosome fragments and dicentric chromosomes) for early radiation dose estimation and stable chromosome exchange events (translocations) for retrospective monitoring of individualized health risks in unstimulated lymphocytes.

Training Emergency Department Charge Nurses Through Tabletop Exercises

Introduction:In a disaster or mass casualty incident, the Emergency Department (ED) charge nurse is thrust into an expanded leadership role, expected to not only manage the department but also organize a disaster response. Hospital emergency preparedness training programs typically focus on high-level leadership, while frontline decision-making staff get experience only through online training and infrequent full-scale exercises. Financial and time limitations of full-scale exercises have been identified as major barriers to frontline training.Aim:To discuss a cost-effective approach to training ED charge nurses and informal leaders in disaster response.Methods:A formal training program was implemented in the ED. All permanent and relief charge nurses are required to attend one four-hour Hospital ICS course within their first year in their position, as well as participate in a minimum of one two-hour ED-based tabletop exercise per year. The tabletop exercises are offered bimonthly, covering various mass casualty scenarios such as apartment complex fires, riots, and a tornado strike. Full-scale exercises involving the ED occur annually.Results:ED permanent and relief charge nurses expressed increased skills and knowledge in areas such as initiation of disaster processes, implementation of hospital incident command, and familiarization with protocols and available resources. Furthermore, ED charge nurses have demonstrated strong leadership, decision-making, and improved response to actual mass casualty incidents since implementing ICS training and tabletop exercises.Discussion:Limitations of relying on full-scale disaster exercises to provide experience to frontline leaders can be overcome by the inclusion of ICS training and tabletop exercises for ED charge nurses in a hospital training and exercise plan. Implementing a structured training program for ED charge nurses focusing on leadership in mass casualty incidents is one step to building a more resilient and prepared ED, hospital, and community.

Intramuscular sodium tetrathionate as an antidote in a clinically relevant swine model of acute cyanide toxicity

Background: Cyanide is a metabolic poison used in multiple industries and is a high threat chemical agent. Current antidotes require intravenous administration, limiting their usefulness in a mass casualty scenario. Sodium tetrathionate reacts directly with cyanide yielding thiosulfate and the non-toxic compound thiocyanate. Thiosulfate, in turn, neutralizes a second molecule of cyanide, thus, per mole, sodium tetrathionate neutralizes two moles of cyanide. Historical studies examined its efficacy as a cyanide antidote, but it has not been evaluated in a clinically relevant, large animal model, nor has it previously been administered by intramuscular injection.Objective: The objective of this study is to evaluate the efficacy of intramuscular sodium tetrathionate on survival and clinical outcomes in a large, swine model of severe cyanide toxicity.Methods: Anesthetized swine were instrumented for continuous monitoring of hemodynamics, then acclimated and breathing spontaneously prior to potassium cyanide infusion (0.17 mg/kg/min). At 6-min post-apnea (no breaths for 20 s), the cyanide infusion was terminated, and animals were treated with sodium tetrathionate (∼18 mg/kg) or normal saline control. Clinical parameters and laboratory values were evaluated at various time points until death or termination of the experiment (90 min post-treatment).Results: Laboratory values, vital signs, and time to apnea were similar in both groups at baseline and treatment. Survival in the sodium tetrathionate treated group was 100% and 17% in controls (p = 0.0043). All animals treated with sodium tetrathionate returned to breathing at a mean time of 10.85 min after antidote, and all but one control remained apneic through end of the experiment. Animals treated with tetrathionate showed improvement in blood lactate (p ≤ 0.002) starting at 30 min post-treatment. The average time to death in the control group is 63.3 ± 23.2 min. No systemic or localized adverse effects of intramuscular administration of sodium tetrathionate were observed.Conclusion: Sodium tetrathionate significantly improves survival and clinical outcomes in a large, swine model of acute cyanide poisoning.

389 Limited Volume Resuscitation with 5% Albumin Exacerbates Liver Injury in a 40% TBSA Swine Burn Model

Acute burn care (>30% TBSA) requires IV resuscitation with large volumes of fluids. Lactated Ringer’s (LR) is the most commonly utilized fluid however, other crystalloids (PlasmaLyte; PL) and colloids (fresh frozen plasma [FFP]; 5% Albumin [ALB]) have been suggested. While resuscitation maintains hemodynamics, limited volumes may suffice in resource-poor environments or mass casualty scenarios. This study compares limited IV resuscitation to the modified Brooke (MB) formula, with emphasis on liver function. Thirty anesthetized swine were subjected to 40% TBSA contact burns and randomized to one of five groups (n=6/group): 15mL/kg/d with LR; PL; FFP; ALB; was compared to 2ml/kg/%TBSA LR (MB). Animals recovered in metabolic cages for urine and blood collection (baseline (BL), 6, 12, 24, 32, and 48h post-burn) to quantify biochemical markers. Following euthanasia (48h) liver tissue samples were snap frozen for analysis. Four non-thermally injured animals (sham) served as tissue controls. Plasma protein was elevated at 48h with colloids (p≤0.002) and albumin levels were elevated throughout the study in the ALB group (p<0.0001). When compared with BL levels, liver enzymes alanine (68.3±1.3 vs 84.0±2.9 mg/dL; p<0.0001) and aspartate (31.0±1.0 vs 90.2±4.3 mg/dL; p<0.0001) aminotransferases were elevated by 6h post burn and remained high regardless of treatment. In the ALB group levels of bilirubin (p<0.0001) were higher throughout the course of the experiment when compared with all other treatments. Total urine output was greater in animals receiving MB (1703±245 mL) when compared with LR (1050±61 mL; p=0.07), PL (797±160 mL; p=0.007), and ALB (933±160 mL; p=0.09), but not FFP (1330±181 mL; p=0.61). Caspase was significantly up regulated in MB, LR, PL, and ALB when compared with sham animals (p≤ 0.019). Heat shock protein 70 tended to be greater in MB and L-LR than sham animals (p≤0.066). Histology revealed reduced intracellular glycogen reduced due to burn (p≤0.01) and a significantly higher level of edema in ALB when compared with other treatment groups (p≤0.16) as demonstrated by histology. Results from these experiments suggest that in this model, resuscitation with ALB early post-burn negatively impacts liver function. No abnormal changes in liver damage markers were detected in animals receiving FFP. Data from these studies can help inform limited volume resuscitative efforts for patients with burns. Limited IV fluid resuscitation is common in resource poor environments. Any available IV fluid would be effective to buy time in prolonged field care, however physicians should monitor liver function if using ALB.

Development of electronic training and telescoring tools to increase the surge capacity of dicentric chromosome scorers for radiological/nuclear mass casualty incidents

Dicentric chromosome assay (DCA) is most frequently used for estimating the absorbed radiation dose in the peripheral blood lymphocytes of humans after occupational or incidental radiation exposure. DCA is considered to be the “gold standard” for estimating the absorbed radiation dose because the dicentric chromosome formation is fairly specific to ionizing radiation exposure and its baseline frequency is extremely low in non-exposed humans. However, performance of DCA for biodosimetry is labor intensive and time-consuming making its application impractical for radiological/nuclear mass casualty incidents. Realizing the critical need for rapid dose estimation particularly after radiological/nuclear disaster events, several laboratories have initiated efforts to automate some of the procedural steps involved in DCA. Although metaphase image capture and dicentric chromosome analysis have been automated using commercially available platforms, lack or an insufficient number of these platforms may pose a serious bottleneck when hundreds and thousands of samples need to be analyzed for rapid dose estimation. To circumvent this problem, a web-based approach for telescoring was initiated by our laboratory, which enabled the cytogeneticists around the globe to analyze and score digital images. To further increase the surge capacity of dicentric scorers, we recently initiated a dicentric training and scoring exercise involving a total of 50 volunteers at all academic levels without any prerequisite for experience in radiation cytogenetics. Out of the 50 volunteers enrolled thus far, only one outlier was found who overestimated the absorbed radiation dose. Our approach of training the civilians in dicentric chromosome analysis holds great promise for increasing the surge capacity of dicentric chromosome scorers for a rapid biodosimetry in the case of mass casualty scenarios.

Intramuscular cobinamide versus saline for treatment of severe hydrogen sulfide toxicity in swine

Introduction: Hydrogen sulfide (H2S) is found in petroleum, natural gas, and decaying organic matter. Terrorist groups have attempted to use it in enclosed spaces as a chemical weapon. Mass casualty scenarios have occurred from industrial accidents and release from oil field sites. There is no FDA approved antidote for sulfide poisoning. We have previously reported that intravenous cobinamide is effective for sulfide poisoning. A rapid-acting antidote that is easy to administer intramuscularly (IM) would be ideal for use in a prehospital setting. In this study, we assessed survival in sulfide-poisoned swine treated with IM cobinamide.Methods: Eleven swine (45–55 kg) were anesthetized, intubated, and instrumented with continuous femoral and pulmonary artery pressure monitoring. After stabilization, anesthesia was adjusted such that animals ventilated spontaneously with a FiO2 of 0.21. Sodium hydrosulfide (NaHS, 8 mg/mL) was infused intravenously at 0.9 mg/kg.min until apnea or severe hypotension. Animals were randomly assigned to receive cobinamide (4 mg/kg), or no treatment at the apnea/hypotension trigger. The NaHS infusion rate was sustained for 1.5 min post trigger, decreased to 0.2 mg/kg.min for 10 min, and then discontinued.Results: The amount of NaHS required to produce apnea or hypotension was not statistically different in both groups (cobinamide: 9.0 mg/kg ±6.1; saline: 5.9 mg/kg ±5.5; mean difference: −3.1, 95% CI: −11.3, 5.0). All of the cobinamide treated animals survived (5/5), none of the control (0/6) animals survived (p < .01). Mean time to return to spontaneous ventilation in the cobinamide treated animals was 3.2 (±1.1) min. Time to return to baseline systolic blood pressure (±5%) in cobinamide-treated animals was 5 min.Conclusion: Intramuscular cobinamide was effective in improving survival in this large swine model of severe hydrogen sulfide toxicity.

Intramuscular administration of hexachloroplatinate reverses cyanide-induced metabolic derangements and counteracts severe cyanide poisoning.

Cyanide is a highly toxic industrial chemical that is widely used by manufactures. Smoke inhalation during household fires is the most common source of cyanide poisoning while additional risks to civilians include industrial accidents and terrorist attacks. Despite the risks to large numbers of individuals, an antidote capable of administration at scale adequate for a mass casualty, prehospital scenario does not yet exist. Previously, we demonstrated that intravenous cisplatin analogues accelerate recovery from cyanide poisoning in mice and rabbits. Of the dozens of platinum‐based organometallic complexes tested, hexachloroplatinate (HCP) emerged as a promising lead compound, exhibiting strong affinity for cyanide and efficacy across model systems. Here, we show HCP is an antidote to lethal cyanide exposure and is importantly effective when delivered intramuscularly. The pharmacokinetic profile of HCP exhibited bioavailability in the systemic circulation 2.5 minutes post‐treatment and subsequent renal clearance of HCP‐cyanide. HCP restored parameters of cellular physiology including cytochrome c oxidase redox state and TCA cycle metabolism. We next validated these findings in a large animal model (swine). Finally, preclinical safety studies in mice revealed minimal toxicity. Cumulatively, these findings demonstrate that HCP is a promising lead compound for development of an intramuscular injectable cyanide antidote for mass casualty scenarios.

Poisoning with Soman, an Organophosphorus Nerve Agent, Alters Fecal Bacterial Biota and Urine Metabolites: a Case for Novel Signatures for Asymptomatic Nerve Agent Exposure.

The experimental pathophysiology of organophosphorus (OP) chemical exposure has been extensively reported. Here, we describe an altered fecal bacterial biota and urine metabolome following intoxication with soman, a lipophilic G class chemical warfare nerve agent. Nonanesthetized Sprague-Dawley male rats were subcutaneously administered soman at 0.8 (subseizurogenic) or 1.0 (seizurogenic) of the 50% lethal dose (LD50) and evaluated for signs of toxicity. Animals were stratified based on seizing activity to evaluate effects of soman exposure on fecal bacterial biota and urine metabolites. Soman exposure reshaped fecal bacterial biota by altering Facklamia, Rhizobium, Bilophila, Enterobacter, and Morganella genera of the Firmicutes and Proteobacteria phyla, some of which are known to hydrolyze OP chemicals. However, analogous changes were not observed in the bacterial biota of the ileum, which remained the same irrespective of dose or seizing status of animals after soman intoxication. However, at 75 days after soman exposure, the bacterial biota stabilized and no differences were observed between groups. Interestingly, in considering just the seizing status of animals, we found that the urine metabolomes were markedly different. Leukotriene C4, kynurenic acid, 5-hydroxyindoleacetic acid, norepinephrine, and aldosterone were excreted at much higher rates at 72 h in seizing animals, consistent with early multiorgan involvement during soman poisoning. These findings demonstrate the feasibility of using the dysbiosis of fecal bacterial biota in combination with urine metabolome alterations as forensic evidence for presymptomatic OP exposure temporally to enable administration of neuroprotective therapies of the future.IMPORTANCE The paucity of assays to determine physiologically relevant OP exposure presents an opportunity to explore the use of fecal bacteria as sentinels in combination with urine to assess changes in the exposed host. Recent advances in sequencing technologies and computational approaches have enabled researchers to survey large community-level changes of gut bacterial biota and metabolomic changes in various biospecimens. Here, we profiled changes in fecal bacterial biota and urine metabolome following a chemical warfare nerve agent exposure. The significance of this work is a proof of concept that the fecal bacterial biota and urine metabolites are two separate biospecimens rich in surrogate indicators suitable for monitoring OP exposure. The larger value of such an approach is that assays developed on the basis of these observations can be deployed in any setting with moderate clinical chemistry and microbiology capability. This can enable estimation of the affected radius as well as screening, triage, or ruling out of suspected cases of exposures in mass casualty scenarios, transportation accidents involving hazardous materials, refugee movements, humanitarian missions, and training settings when coupled to an established and validated decision tree with clinical features.

Intramuscular dimethyl trisulfide: efficacy in a large swine model of acute severe cyanide toxicity

Background: Cyanide is a deadly compound used as a terrorist agent. Current FDA approved antidotes require intravenous administration, limiting their utility in a mass casualty scenario. Dimethyl trisulfide (DMTS), a sulfur-based molecule, binds cyanide converting it to the less toxic by-product thiocyanate. Studies evaluating efficacy in rodents have been performed, but a large, clinically relevant animal model has not been reported.Objective: This study evaluates the efficacy of intramuscular DMTS on survival and clinical outcomes in a swine model of acute, severe cyanide toxicity.Methods: Anesthetized swine were instrumented for continuous monitoring of hemodynamics. Prior to potassium cyanide infusion animals were acclimated and breathing spontaneously. At 5-minutes post-apnea animals were treated with DMTS or saline. Vital signs, hemodynamics, and laboratory values were evaluated at various time points.Results: Baseline values and time to apnea were similar in both groups. Survival in the DMTS treated group was 83.3% and 0% in saline controls (p = .005). The DMTS group returned to breathing at a mean time of 19.3 ± 10 min after antidote, control animals did not return to breathing (CI difference 8.8, 29.8). At the end of the experiment or time of death, mean lactate was 9.41 mmol/L vs. 4.35 mmol/L (CI difference –10.94,0.82) in the saline and DMTS groups, respectively and pH was 7.20 vs. 7.37 (CI difference –0.04, 0.38). No adverse effects were observed at the injection site.Conclusion: Intramuscular administration of DMTS improves survival and clinical outcomes in our large animal swine model of acute cyanide toxicity.

The utility of point-of-care ultrasound in targeted automobile ramming mass casualty (TARMAC) attacks

As terrorist actors revise their tactics to outmaneuver increasing counter-terrorism security measures, a recent trend toward less-sophisticated attack methods has emerged. Most notable of these “low tech” trends are the Targeted Automobile Ramming MAss Casualty (TARMAC) attacks. Between 2014 and November 2017, 18 TARMAC attacks were reported worldwide, resulting in 181 deaths and 679 injuries. TARMAC attack-related injuries are unique compared to accidental pedestrian trauma and other causes of mass casualty incidents (MCI), and therefore they require special consideration. No other intentional mass casualty scenario is the result of a blunt, non-penetrating trauma mechanism. Direct vehicle impact results in high-power injuries including blunt trauma to the central nervous system (CNS), and thoracoabdominal organs with crush injuries if the victims are run over. Adopting new strategies and using existing technology to diagnose and treat MCI victims with these injury patterns will save lives and limit morbidity. Point-of-care ultrasound (POCUS) is one such technology, and its efficacy during MCI response is receiving an increasing amount of attention. Ultrasound machines are becoming increasingly available to emergency care providers and can be critically important during a MCI when access to other imaging modalities is limited by patient volume. By taking ultrasound diagnostic techniques validated for the detection of life-threatening cardiothoracic and abdominal injuries in individuals and applying them in a TARMAC mass casualty situation, physicians can improve triage and allocate resources more effectively. Here, we revisit the high-yield applications of POCUS as a means of enhanced prehospital and hospital-based triage, improved resource utilization, and identify their potential effectiveness during a TARMAC incident.

229 Enteral Fluid Resuscitation Alters Splenic Function and Leukocyte Populations Post-Burn in Swine

Extensive burn injury (>30% total body surface area [TBSA]) leads to significant inflammation and associated organ damage. The spleen is a major reservoir of lymphocytes which decrease systemically post-burn. Abnormal splenic function may relate to the inflammatory response after burn. While intravenous (IV) fluid resuscitation is the current standard for burn care, enteral resuscitation has also shown promise, and may be leveraged to help splenic recovery. However, the effect of resuscitation on the spleen post-burn is largely unstudied. Thirty anesthetized Yorkshire swine subjected to 40% TBSA contact burns were randomized to one of five groups (n=6/group); no fluids, ad lib water, volume-matched Oral Rehydration Salts (ORS) from the World Health Organization, limited-volume (15mL/kg/d) ORS, or IV lactated Ringer’s solution at 2mL/kg/%TBSA/d (IV). Computerized tomography (CT) scans were performed before and 48 h post-burn, at which point spleens were harvested. Histology was performed to localize splenic CD3 and measure the proportion of red and white pulp. Gene and protein expression was analyzed via qPCR, Western blot, and multiplex. The splenic artery diameter was maintained with water (-0.2 ± 0.32mm), limited-volume (0.36 ± 0.37mm), or volume-matched ORS (-0.2 ± 0.04mm), while no fluids led to a reduction (-0.97 ± 0.14mm) and IV fluids led to dilation (0.68 ± 0.30mm) 48 h post-burn. However, no differences in spleen wet-to-dry ratios were detected among treatments. Levels of white pulp were highest in the ad lib water group (233.0 ± 1.7AU), volume-matched ORS (229.7 ± 2.5), and IV groups (233.3 ± 1.363) compared to no fluids (221.9 ± 5.2) or low-volume ORS (218.7 ± 3.4). Gene expression of complement C5 and uteroglobin-related protein 2 were upregulated in IV animals by 2.76 and 2.43 fold, respectively, when compared to volume matched ORS. Protein expression of CD3 tended to be greatest in animals receiving ORS, and IV fluids. Protein levels of IL1ra were greatest in low and volume matched ORS compared to other groups. Burn injury leads to significant changes in splenic leukocytes, which can be altered with different resuscitation strategies. Specifically, access to enteral fluids preserves splenic lymphocytes post-burn similarly to IV fluids, and may uniquely alter the inflammatory response. Enteral fluids also maintain splenic perfusion, with minimal change in splenic artery diameter. The therapeutic efficacy of enteral resuscitation in burn injury warrants further investigation. Enteral fluids represent a viable means of maintaining splenic perfusion which could easily be used to buy time in mass casualty and prolonged field care scenarios in patients with no concomitant abdominal injuries.

Sealing Effects on the Storage Stability of the Cyanide Antidotal Candidate, Dimethyl Trisulfide.

BackgroundDimethyl trisulfide (DMTS) is a highly lipid-soluble cyanide (CN) antidote candidate molecule. In prior studies with various US FDA-approved co-solvents, surfactants, and their combinations, aqueous solutions containing 15% polysorbate 80 (Poly80) were found to effectively solubilize DMTS in formulations for intramuscular administration. However, DMTS formulated in 15% aqueous Poly80 solutions showed gradual losses over time when stored in vials with septum-based seals.ObjectiveThe present study tested whether storing DMTS formulations in hermetically sealed glass ampules could mitigate storage losses.MethodsSamples consisted of 1-mL aliquots of a 50 mg/ml stock solution of DMTS in 15% aqueous Poly80. The control samples were stored using a vial-within-a-vial system—the inner and outer vials were sealed respectively, with a snap cap, and with a crimped septum. The hermetically sealed test samples were stored in fire-sealed glass ampules. The DMTS content was measured by HPLC–UV analysis at specific time points over a 100-day period.ResultsWhile the control samples exhibited systematic DMTS losses, no DMTS losses were observed from the test samples stored in hermetically sealed glass ampules over the 100-day testing period.ConclusionDMTS formulated in 15% aqueous Poly80 solution has excellent stability when stored in fire-sealed glass ampules and thus has the potential to be effectively stored as an intramuscular CN countermeasure for mass casualty scenarios.

Continuous positive airway pressure: An early intervention to prevent phosgene-induced acute lung injury

Exposure to toxic industrial chemicals such as phosgene may occur through accidental or deliberate release. Inhalation may result in an acute lung injury which manifests as hypoxaemia with insufficient oxygen being delivered to the tissues resulting in hypoxia, respiratory failure and death. No effective pharmacological therapy currently exists and treatment remains supportive, often requiring intensive care facilities. In a mass casualty scenario the logistical burden of managing exposed individuals would rapidly overwhelm healthcare systems. This highlights the need to develop post exposure therapeutic strategies to minimise injury severity and increase survival in individuals exposed to toxic chemicals.Our research objective was to investigate a commercial off the shelf (COTS) therapy; ambient air continuous positive airway pressure (CPAP) support, initiated 1h post exposure to explore the concept that early intervention with positive airway pressure would reduce or ameliorate lung injury following exposure to phosgene.This study has demonstrated that CPAP, initiated before overt signs of exposure become manifest, significantly improved survival as well as improving some clinically relevant physiological measures of phosgene-induced acute lung injury over 24h.

Activity of cholinesterases in a young and healthy middle-European population: Relevance for toxicology, pharmacology and clinical praxis

The activity of human cholinesterases, erythrocyte acetylcholinesterase (AChE; EC 3.1.1.7) and plasma butyrylcholinesterase (BChE; EC 3.1.1.8) represents an important marker when monitoring exposure to pesticides/nerve agents, and may also be used in occupational medicine in diagnosis and prognosis of some diseases. In this study “normal/baseline” AChE and BChE activity has been investigated in a young and healthy population, with subsequent evaluation of several intra-population factors including sex, age (categories 18–25, 26–35 and 36–45 years old) and smoker status.The modified Ellman's method was used for enzyme activity assessment in 387 young and healthy individuals (201 males and 186 females aged 18–45). A significant inter-sexual difference in AChE and BChE activity was found (AChE: 351±67 for males and 377±65 for females, (μmol/min)/(μmol of hemoglobin), p<0.001; BChE: 140±33 for males and 109±29 for females, μkat/l, p<0.001; mean±SD). Despite the finding that mean AChE activity somewhat decreased whereas BChE activity grew within the age categories of the tested subjects, no significant effect of age on cholinesterase activity was found (p>0.05). Smoking influenced cholinesterase activity – AChE activity in smokers was elevated (approx. 3% in males; 8% in females) relative to that in non-smokers (p<0.05). Smoking was found not to have any effect on BChE activity.Reference values based on confidence intervals for AChE and BChE activity were established. The presented results might be useful in routine clinical practice where the monitoring of blood AChE and plasma BChE activity is crucial for prognosis and diagnosis of organophosphate poisoning, in occupational medicine and in relevant mass casualty scenarios.

In-vitro mercaptopyruvate sulfurtransferase species comparison in humans and common laboratory animals

Cyanide is a metabolic poison that inhibits cytochrome c oxidase. Its broad applications in manufacturing and history as an agent of warfare/terror highlight the limitations in approved cyanide antidotes for mass casualties. Sulfanegen, a pre-clinical antidote for cyanide poisoning, exploits an endogenous detoxification pathway and should be amenable to mass-casualty scenarios. Because human studies are unethical, determination of appropriate animal species as models in translational studies for FDA approval under the “Animal Rule” are critical. Here, we compared the specific activities of mercaptopyruvate sulfurtransferase (MST, required for sulfanegen’s activity), across common laboratory models of cyanide intoxication, and humans. Human MST activities in erythrocytes (measured as micromole pyruvate/min/106 rbc) were closest to those of Swiss-Webster mice and NZW rabbits. Similar species were selected for a more detailed tissue-specific comparison of MST activities. NZW Rabbits were closest to humans in the liver and kidney mitochondrial fractions, the Swiss-Webster mouse was closest to humans in the liver cytosolic fraction, while C57BL/6 mouse was closest in the kidney cytosolic fraction. These data comparing MST activities in animal models will help justify the use of those specific animals per the animal rule. Interestingly, statistically significant differences were found in MST activities of liver mitochondria between human smokers and non-smokers (p=0.0030).

Enteral Resuscitation with WHO Oral Rehydration Salts Ameliorates Burn‐Induced Kidney Injury (AKI) and is Protective of the Glomerular Glycocalyx in a Swine Model

Following severe burn injury oral resuscitation fluid may be sufficient to treat patients, especially when i.v. fluid may be delayed such as in mass casualty scenarios. The World Health Organization (WHO) Oral Rehydration Salts (ORS) formulation is designed for treatment of severe dehydration however; its effectiveness at maintaining kidney function and perfusion after burn has not been studied. The objective of this study was to evaluate the effectiveness of ORS and water on post‐burn Acute Kidney Injury (AKI). Anesthetized Yorkshire pigs sustained 40% TBSA full‐thickness contact burns [with brass probes heated to 100°C placed on the skin for 30 seconds]. Animals recovered in metabolic cages and were randomized to one of four treatment groups: no water access (n=7), ad libitum water access (n=6), 15 mL/kg/d of ORS (n=6), or 70 mL/kg/d ORS (n=6) for a 48 hour period. Urine and blood were collected at baseline (BL), 6, 12, 24, 32, and 48‐hour post‐burn for quantification of biochemical markers. Regardless of treatment, all animals experienced AKI as demonstrated by a 0.50±0.10 mg/dL elevation in plasma creatinine by 6 hours following burn. However, animals receiving 70 mL/kg/d ORS or ad libitum water had reduced plasma creatinine by 24 hours, as levels were 1.30±.21 and 1.30±0.13 respectively. Myoglobin was also elevated by 6 hours post‐burn but differences among treatments were not detected. Additionally, preliminary experiments demonstrated elevated free hemin in the urine and plasma following burn in water restricted animals. Animals receiving 70 mL/kg/d ORS also had similar renal wet to dry ratios as the ad libitum group, but both ratios were greater than the water restricted group (p &lt; 0.05), indicating maintained renal perfusion. Moreover, glycosaminoglycan (GAG) concentrations in the urine were elevated post‐burn in all groups suggesting degradation of the glomerular glyocalyx. However, by 48 hours, 70 mL/kg/d animals had reduced urine GAGs when compared to other treatments. Collectively, these data demonstrate that water restriction in burn‐trauma exacerbates burn induced AKI and 70 mL/kg/d of ORS was as sufficient as ad libitum water in alleviating AKI, with preferential protection of the endothelial glycocalyx in the glomerulus. This study highlights the importance of hydration status in response to burn injury, and supports the use of oral resuscitation efforts in burn casualties in prolonged care and mass casualty scenarios.

Nitrite therapy prevents chlorine gas toxicity in rabbits

Chlorine (Cl2) gas exposure and toxicity remains a concern in military and industrial sectors. While post-Cl2 exposure damage to the lungs and other tissues has been documented and major underlying mechanisms elucidated, no targeted therapeutics that are effective when administered post-exposure, and which are amenable to mass-casualty scenarios have been developed. Our recent studies show nitrite administered by intramuscular (IM) injection post-Cl2 exposure is effective in preventing acute lung injury and improving survival in rodent models. Our goal in this study was to develop a rabbit model of Cl2 toxicity and test whether nitrite affords protection in a non-rodent model. Exposure of New Zealand White rabbits to Cl2 gas (600ppm, 45min) caused significant increases in protein and neutrophil accumulation in the airways and ∼35% mortality over 18h. Nitrite administered 30min post Cl2 exposure by a single IM injection, at 1mg/kg or 10mg/kg, prevented indices of acute lung injury at 6h by up to 50%. Moreover, all rabbits that received nitrite survived over the study period. These data provide further rationale for developing nitrite as post-exposure therapeutic to mitigate against Cl2 gas exposure injury.

Identification and Preliminary Validation of Radiation Response Protein(s) in Human Blood for a High-throughput Molecular Biodosimetry Technology for the Future.

The absence of a rapid and high-throughput technology for radiation biodosimetry has been a great obstacle in our full preparedness to cope with large-scale radiological incidents. The existing cytogenetic technologies have limitations, primarily due to their time-consuming methodologies, which include a tissue culture step, and the time required for scoring. This has seriously undermined its application in a mass casualty scenario under radiological emergencies for timely triage and medical interventions. Recent advances in genomics and proteomics in the postgenomic era have opened up new platforms and avenues to discover molecular biomarkers for biodosimetry in the future. Using a genomic-to-proteomic approach, we have identified a basket of twenty “candidate” radiation response genes (RRGs) using DNA microarray and tools of bioinformatics immediately after ex vivo irradiation of freshly drawn whole blood of consenting and healthy human volunteers. The candidate RRGs have partially been validated using real-time quantitative polymerase chain reaction (RT-qPCR or qPCR) to identify potential “candidate” RRGs at mRNA level. Two potential RRGs, CDNK1A and ZNF440, have so far been identified as genes with potentials to form radiation response proteins in liquid biopsy of blood, which shall eventually form the basis of fluorescence- or ELISA-based quantitative immunoprobe assay for a high-throughput technology of molecular biodosimetry in the future. More work is continuing.

Use of Clinical Decision Guidance as a New Public Health Tool for the Medical Management of Internal Contamination in Radiological Mass Casualty Scenarios.

This review is a discussion of special issues associated with the medical and public health management of persons at risk of internal contamination from radionuclides, following various radiological mass-casualty scenarios, as well as definition, discussion and use of the Clinical Decision Guidance (CDG) in such scenarios. Specific medical countermeasures are available for reducing the internal radiation dose and the subsequent stochastic and deterministic risks to persons internally contaminated with radionuclides from nuclear power plant, fuel processing and nuclear weapon accidents/incidents. There is a public health need for rapidly identifying and quantifying the 'source term' of such radiation exposures and assessment of the associated committed doses, so that appropriate medical countermeasure(s) can be given as soon as possible. The CDG, which was initially defined in NCRP-161, was specifically developed to be a new public health tool for facilitating the integration of local community healthcare professionals into the general medical, mass casualty, triage and treatment response of internally contaminated populations.

Culture time and reagent minimization in the chemical PCC assay

The possibility to reduce the culture time and volume of blood and reagents required for the chemical Premature Chromosome Condensation (PCC) assay is demonstrated in this work. Peripheral whole blood was exposed to gamma radiation (1–20 Gy). Lymphocytes were cultured for 40 h, using 50 μl of blood and 450 μl of culture medium. The dose-response curves were adjusted, using length ratio (LR) of the longest to the shortest chromosome piece, and the frequency of rings per cell. No statistical differences were found between the results obtained with this method and those reported with the classical PCC assay culture. The minimization of culture time and reagents in combination with the automatic measurement of the LR of the chromosome pieces, or the scoring of rings, can be a valuable biodosimetry tool in a mass casualty scenario.