Modified Brain Injury Guidelines for preinjury anticoagulation in traumatic brain injury: An opportunity to reduce health care resource utilization.

INTRODUCTION: The Brain Injury Guidelines (BIG) stratify patients by traumatic brain injury (TBI) severity to provide management recommendations to reduce health care resource burden but mandates that patients on anticoagulation (AC) are allocated to the most severe tertile (BIG 3). We sought to analyze TBI patients on AC therapy using a modified BIG model to determine if this population can offer further opportunity for safe reductions in health care resource utilization. METHODS: Patients 55 years or older on AC with traumatic intracranial hemorrhage (ICH) from two centers were retrospectively stratified into BIG 1 to 3 risk groups using modified BIG criteria excluding AC as a criterion. Intracranial hemorrhage progression, neurosurgical intervention (NSI), death, and worsened discharge status were compared. RESULTS: A total of 221 patients were included, with 23%, 29%, and 48% classified as BIG 1, BIG 2, and BIG 3, respectively. The BIG 3 cohort had a higher rate of AC reversal agents administered (66%) compared with the BIG 1 (40%) and BIG 2 (54%) cohorts ( p < 0.01), as well as ICH progression discovered on repeat head computed tomography (56% vs. 38% vs. 26%, respectively; p < 0.001). No patients in the BIG 1 and 2 cohorts required NSI. No patients in BIG 1 and 3% of patients in BIG 2 died secondary to the ICH. In the BIG 3 cohort, 16% of patients required NSI and 26% died. Brain Injury Guidelines 3 patients had 15 times the odds of mortality compared with BIG 1 patients ( p < 0.01). CONCLUSION: The AC population had higher rates of ICH progression than the BIG literature, but this did not lead to more NSI or mortality in the lower tertiles of our modified BIG protocol. If the modified BIG used the original tertile management on our population, then NS consultation may have been reduced by up to 52%. These modified criteria may be a safe opportunity for further health care resource and cost savings in the TBI population. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Pressure-Enabled Drug Delivery (PEDD) of a class C TLR9 agonist in combination with checkpoint inhibitor therapy in a murine pancreatic cancer model.

BACKGROUND: Systemic immunotherapy has had limited clinical benefit in pancreatic ductal adenocarcinoma. This is thought to be due to its desmoplastic immunosuppressive tumor microenvironment in addition to high intratumoral pressures that limit drug delivery. Recent preclinical cancer models and early-phase clinical trials have demonstrated the potential of toll-like receptor 9 agonists, including the synthetic CpG oligonucleotide SD-101, to stimulate a wide range of immune cells and eliminate suppressive myeloid cells. We hypothesized that Pressure-Enabled Drug Delivery via Pancreatic Retrograde Venous Infusion of toll-like receptor 9 agonist would improve responsiveness to systemic anti-programmed death receptor-1 checkpoint inhibitor therapy in a murine orthotopic pancreatic ductal adenocarcinoma model. METHODS: Murine pancreatic ductal adenocarcinoma (KPC4580P) tumors were implanted into the pancreatic tails of C57BL/6J mice and treated 8 days after implantation. Mice were assigned to one of the following treatment groups: Pancreatic Retrograde Venous Infusion delivery of saline, Pancreatic Retrograde Venous Infusion delivery of toll-like receptor 9 agonist, systemic anti-programmed death receptor-1, systemic toll-like receptor 9 agonist, or the combination of Pancreatic Retrograde Venous Infusion delivery of toll-like receptor 9 agonist and systemic anti-programmed death receptor-1 (Combo). Fluorescently labeled toll-like receptor 9 agonist (radiant efficiency) was used to measure uptake of the drug on day 1. Changes in tumor burden were evaluated by necropsy at 2 different time points, 7 and 10 days after toll-like receptor 9 agonist treatment. Blood and tumors were collected at necropsy 10 days after toll-like receptor 9 agonist treatment for flow cytometric analysis of tumor-infiltrating leukocytes and plasma cytokines. RESULTS: All mice analyzed survived to necropsy. Site of tumor fluorescence measurements revealed 3-fold higher intensity fluorescence in Pancreatic Retrograde Venous Infusion delivery of toll-like receptor 9 agonist compared to systemic toll-like receptor 9 agonist mice. Tumor weights were significantly lower in the Combo group compared to Pancreatic Retrograde Venous Infusion delivery of saline. Flow cytometry of the Combo group demonstrated significantly increased overall T-cell number, specifically CD4+ T-cells, and a trend toward increased CD8+ T-cells. Cytokine analysis showed significantly decreased IL-6 and CXCL1. CONCLUSION: Pressure-Enabled Drug Delivery of toll-like receptor 9 agonist by Pancreatic Retrograde Venous Infusion with systemic anti-programmed death receptor-1 demonstrated improved pancreatic ductal adenocarcinoma tumor control in a murine pancreatic ductal adenocarcinoma model. These results support study of this combination therapy in pancreatic ductal adenocarcinoma patients and expansion of ongoing Pressure-Enabled Drug Delivery clinical trials.

Financial vulnerability of trauma centers: A national analysis.

OBJECTIVE: Trauma centers function as an essential safeguard in the United States health care system. However, there has been minimal study of their financial health or vulnerability. We sought to perform a nationwide analysis of trauma centers using detailed financial data and a recently developed Financial Vulnerability Score (FVS) metric. METHODS: The RAND Hospital Financial Database was used to evaluate all American College of Surgeons-verified trauma centers nationwide. The composite FVS was calculated for each center using six metrics. Financial Vulnerability Score tertiles were used to classify centers as high, medium, or low vulnerability, and hospital characteristics were analyzed and compared. Hospitals were also compared by US Census region and teaching versus nonteaching hospitals. RESULTS: A total of 311 American College of Surgeons-verified trauma centers were included in the analysis, with 100 (32%) Level I, 140 (45%) Level II, and 71 (23%) Level III. The largest share of the high FVS tier was consisted of Level III centers (62%), with the majority of Level I (40%) and Level II (42%) in the middle and low FVS tier, respectively. The most vulnerable centers had fewer beds, negative operating margins, and significantly less cash on hand. Lower FVS centers had greater asset/liability ratios, lower outpatient shares, and three times less uncompensated care. Nonteaching centers were statistically significantly more likely to have high vulnerability compared with teaching centers (46% vs. 29%). Statewide analysis showed high discrepancy among individual states. CONCLUSION: With approximately 25% of Levels I and II trauma centers at high risk for financial vulnerability, disparities in characteristics, including payer mix and outpatient status, should be targeted to reduce vulnerabilities and bolster the health care safety net. LEVEL OF EVIDENCE: Prognostic and Epidemiological; Level IV.

Anticonvulsant effectiveness of scopolamine against soman-induced seizures in African green monkeys.

Prolonged seizures are a hallmark feature of intoxication with anticholinesterase nerve agents such as soman. While benzodiazepine drugs are typically used to control these seizures, studies in both rats and guinea pigs have shown that potent, centrally acting anticholinergic drugs such as scopolamine can also terminate such seizures. The present study was performed to determine if scopolamine could produce similar anticonvulsant effects in a nonhuman primate model of soman intoxication. Adult male African green monkeys, implanted with telemetry devices to record cortical electroencephalographic activity, were pretreated with pyridostigmine (0.02 mg/kg, intramuscularly [im]) and 40 min later challenged with 15 µg/kg (im) of the nerve agent soman. One min after soman exposure the animals were treated with atropine (0.4 mg/kg, im) and the oxime 2-PAM (25.7 mg/kg, im). One min after the start of seizure activity the animals were administered scopolamine (0.01-0.1 mg/kg, im), using an up-down dosing design over successive animals. Scopolamine was highly effective in stopping soman-induced seizures with an ED50 = 0.0312 mg/kg (0.021-0.047 mg/kg = 95% confidence limits). Seizure control was rapid, with all epileptiform activity stopping on average 21.7 min after scopolamine treatment. A separate pK study showed that scopolamine absorption peaked approximately 10 min after im administration and a dose of 0.032 mg/kg produced maximum plasma levels of 17.62 ng/ml. The results show that scopolamine exerts potent and rapid anticonvulsant action against soman-induced seizures and that it may serve as a valuable adjunct to current antidote treatments for nerve agent intoxication.

The tertiary oxime monoisonitrosoacetone penetrates the brain, reactivates inhibited acetylcholinesterase, and reduces mortality and morbidity following lethal sarin intoxication in guinea pigs.

The brain is a critical target for the toxic action of organophosphorus (OP) inhibitors of acetylcholinesterase (AChE) such as the nerve agent sarin. However, the available oxime antidote 2-PAM only reactivates OP-inhibited AChE in peripheral tissues. Monoisonitrosoacetone (MINA), a tertiary oxime, reportedly reactivates AChE in the central nervous system (CNS). The current study investigated whether MINA would be beneficial as a supplemental oxime treatment in preventing lethality and reducing morbidity following lethal sarin exposure, MINA supplement would improve AChE recovery in the body, and MINA would be detectable in the CNS. Guinea pigs were exposed to sarin and treated with atropine sulfate and 2-PAM at one minute. Additional 2-PAM or MINA was administered at 3, 5, 15, or 30 min after sarin exposure. Survival and morbidity were assessed at 2 and 24 h. AChE activity in brain and peripheral tissues was evaluated one hour after MINA and 2-PAM treatment. An in vivo microdialysis technique was used to determine partitioning of MINA into the brain. A liquid chromatography-tandem mass spectrometry method was developed for the analysis of MINA in microdialysates. MINA-treated animals exhibited significantly higher survival and lower morbidity compared to 2-PAM-treated animals. 2-PAM was significantly more effective in reactivating AChE in peripheral tissues, but only MINA reactivated AChE in the CNS. MINA was found in guinea pig brain microdialysate samples beginning at ~10 min after administration in a dose-related manner. The data strongly suggest that a centrally penetrating oxime could provide significant benefit as an adjunct to atropine and 2-PAM therapy for OP intoxication.

Pressure-enabled delivery of gemcitabine in an orthotopic pancreatic cancer mouse model.

BACKGROUND: We describe the use of pancreatic retrograde venous infusion in an orthotopic murine model of pancreatic ductal adenocarcinoma and hypothesize that pancreatic retrograde venous infusion delivery of gemcitabine will increase concentrations of gemcitabine in the tumor and the subsequent tumor response to treatment. METHODS: Murine pancreatic ductal adenocarcinoma (KPC4580P) was transplanted onto the pancreatic tail of C57BL/6J mice. Groups (n = 15) of mice were assigned to sham laparotomy and 100 mg/kg intraperitoneal infusion of gemcitabine (systemic gemcitabine), pancreatic venous isolation with pancreatic retrograde venous infusion of 100 mg/kg gemcitabine, or pancreatic retrograde venous infusion with saline infusion. Tumor pressures were recorded during pancreatic retrograde venous infusion. Mice were killed at 1 hour or 7 days after infusion. RESULTS: Baseline tumor pressures were 45 ± 8 mm Hg, and pancreatic retrograde venous infusion increased tumor pressures by 29 ± 6 mm Hg (P < .01). Pancreatic retrograde venous infusion gemcitabine mice had greater tumor gemcitabine concentrations compared with systemic gemcitabine (127 vs 19 ng/mg; P < .01) and lesser tumor volumes compared with both systemic gem and pancreatic retrograde venous infusion with saline (274 vs 857 vs 629 mm3; P < .01). CONCLUSION: Pancreatic retrograde venous infusion increased tumor pressures greater than baseline, improved gemcitabine delivery, and increased the treatment response. These findings suggest that pressurized, regional delivery overcomes the increased pressure barrier in pancreatic ductal adenocarcinoma. Additional preclinical studies with cytotoxic and immunotherapeutic agents and clinical trials using pressure-enabled drug delivery with pancreatic retrograde venous infusion devices are underway.

Gas Chromatography-Tandem Mass Spectrometry Verification of Sulfur Mustard Exposure in Humans through the Conversion of Protein Adducts to Free Sulfur Mustard.

Exposures to sulfur mustard (HD; bis(2-chloroethyll) sulfide) are well-known to result in the formation of adducts with free aspartate and glutamate residues of plasma proteins (Lawrence, R. J., Smith, J. R., and Capacio, B. R. 2008 32, (1), 31-36). A modified version of the analytical method reported previously for the verification of HD exposure has been developed (Lawrence, R. J., Smith, J. R., and Capacio, B. R. 2008 32, (1), 31-36). The method reported herein involves the reaction of hydrochloric acid with HD-adducted plasma proteins, resulting in the simultaneous cleavage and conversion of the adduct to free HD. A water scavenger, 2,2-dimethoxypropane, was added to the mixture to increase the reaction yield. Deuterated (d8) thiodiglycol was added as an internal standard and underwent conversion to deuterated sulfur mustard. The analytes were isolated by hexane liquid-liquid extraction and subsequently analyzed by gas chromatography tandem mass spectrometry (GC-MS-MS). An interday and intraday study was performed to evaluate the accuracy and precision of the method. Individual calibration curves with quality control (QC) standards were prepared on 5 days, and a calibration curve with five sets of QCs was prepared on a single day. All results were within the acceptable limits of the validation criteria. Linearity, limit of detection, and limit of quantitation were also verified for each calibration curve. This highly sensitive (pg/mL limit of detection) method can be used for rapid analysis of a definitive marker of sulfur mustard exposure.

Butyrylcholinesterase, a stereospecific in vivo bioscavenger against nerve agent intoxication.

Human butyrylcholinesterase (E.C. 3.1.1.8) purified from blood plasma has previously been shown to provide protection against up to five and a half times the median lethal dose of an organophosphorus nerve agent in several animal models. In this study the stoichiometric nature of the protection afforded by human butyrylcholinesterase against organophosphorus nerve agents was investigated in guinea pigs. Animals were administered human butyrylcholinesterase (26.15 mg/kg ≡ 308 nmol/kg) by the intravascular or intramuscular route. Animals were subsequently dosed with either soman or VX in accordance with a stage-wise adaptive dose design to estimate the modified median lethal dose in treated animals. Human butyrylcholinesterase (308 nmol/kg) increased the median lethal dose of soman from 154 nmol/kg to 770 nmol/kg. Comparing the molar ratio of agent molecules to enzyme active sites yielded a stoichiometric protective ratio of 2:1 for soman, likely related to the similar stereoselectivity the enzyme has compared to the toxic target, acetylcholinesterase. In contrast, human butyrylcholinesterase (308 nmol/kg) increased the median lethal dose of VX from 30 nmol/kg to 312 nmol/kg, resulting in a stoichiometric protective ratio of only 1:1, suggesting a lack of stereoselectivity for this agent.

The Application of a Single-Column GC-MS-MS Method for the Rapid Analysis of Chemical Warfare Agents and Breakdown Products.

The development of one comprehensive gas chromatographic-triple quadrupole mass spectrometric (GC-MS-MS) method for the analysis of nerve agents and their breakdown products can pose a challenge due to significant differences in analyte volatility. Nerve agent breakdown products typically have a low volatility, requiring a derivatization step prior to analysis by gas chromatography (GC). However, nerve agent parent compounds are generally more volatile, which eliminates the need for derivatization and allows for direct analysis. Therefore, the analysis of these analytes is typically performed using separate analytical methods. This may require the use of multiple columns composed of different stationary phases to ensure the most efficient separation. With the wide selection of GC columns and derivatizing agents, it is potentially possible to develop a single-column/analytical method that is suitable for the detection of nerve agents and their breakdown products. We evaluated six nerve agents (tabun, sarin, soman, cyclosarin, VX and Russian VX) and the six corresponding breakdown products (EDPA, IMPA, PMPA, CMPA EMPA and MMPA). Chromatographic separation and multiple-reaction mode electron ionization detection of the nerve agents and silylated breakdown product derivatives were performed using an Agilent 7890 A gas chromatography (GC) equipped with a mid-polarity column, coupled to a 7000 triple quadrupole mass spectrometry system. A fast (12.5 min), highly sensitive (picogram) and selective method was achieved. The feasibility of this method for nerve agent and breakdown product detection in real samples was demonstrated using nerve agent-spiked human plasma at various exposure times (3 min, 1 h and 24 h). Five of the six nerve agents and all six breakdown products were successfully detected. This robust method has utility as a rapid screening tool to identify a specific nerve agent in a potential exposure event by simultaneous detection of the parent and or its corresponding breakdown product in plasma.

Towards Development of Small Molecule Lipid II Inhibitors as Novel Antibiotics.

Recently we described a novel di-benzene-pyrylium-indolene (BAS00127538) inhibitor of Lipid II. BAS00127538 (1-Methyl-2,4-diphenyl-6-((1E,3E)-3-(1,3,3-trimethylindolin-2-ylidene)prop-1-en-1-yl)pyryl-1-ium) tetrafluoroborate is the first small molecule Lipid II inhibitor and is structurally distinct from natural agents that bind Lipid II, such as vancomycin. Here, we describe the synthesis and biological evaluation of 50 new analogs of BAS00127538 designed to explore the structure-activity relationships of the scaffold. The results of this study indicate an activity map of the scaffold, identifying regions that are critical to cytotoxicity, Lipid II binding and range of anti-bacterial action. One compound, 6jc48-1, showed significantly enhanced drug-like properties compared to BAS00127538. 6jc48-1 has reduced cytotoxicity, while retaining specific Lipid II binding and activity against Enterococcus spp. in vitro and in vivo. Further, this compound showed a markedly improved pharmacokinetic profile with a half-life of over 13 hours upon intravenous and oral administration and was stable in plasma. These results suggest that scaffolds like that of 6jc48-1 can be developed into small molecule antibiotic drugs that target Lipid II.

Rapid screening of chemical warfare nerve agent metabolites in urine by atmospheric solids analysis probe-mass spectroscopy (ASAP-MS).

Exposures to organophosphorus nerve agents (OPNA) remain a threat to both civilian and military populations. Verification of exposures typically involves determinations of urinary metabolites or adducted proteins in blood. Urinary alkyl methylphosphonic acid metabolites resulting from hydrolysis of OPNAs provide a convenient marker for OPNA exposure. In a military setting, urine is a relatively easy sample to obtain, and a rapid turnaround for analyses for the identification of metabolites is critical for field commanders. Timely information on use and identity of OPNAs facilitates decisions regarding employment of personal protective equipment and additional strategies to mitigate additional exposure(s). Herein, we report the development of a rapid mass spectrometric (MS) method to identify OPNA metabolites directly from urine with no sample preparation. Synthetic urine spiked with multiple OPNA metabolites was analyzed using an atmospheric solids analysis probe (ASAP) attached to a high resolution mass spectrometer. The alkyl methylphosphonic acid metabolites resulting from hydrolysis of sarin, cyclosarin, soman, and Russian VX were clearly detectable down to a level of 1.0 ng/ml. The ability to rapidly detect OPNA metabolites in unprepared urine allows for the design of a field-deployable device that could afford field personnel the ability to rapidly screen individuals for specific OPNA exposure. In addition, this provides proof-of-concept evidence that a fieldable ASAP-MS device could afford personnel the ability to rapidly detect OPNAs on skin, equipment, and other porous surfaces. Published 2012. This article is a US Government work and is in the public domain in the USA.

Immunomodulation by poly-YE reduces organophosphate-induced brain damage.

Accidental organophosphate poisoning resulting from environmental or occupational exposure, as well as the deliberate use of nerve agents on the battlefield or by terrorists, remain major threats for multi-casualty events, with no effective therapies yet available. Even transient exposure to organophosphorous compounds may lead to brain damage associated with microglial activation and to long-lasting neurological and psychological deficits. Regulation of the microglial response by adaptive immunity was previously shown to reduce the consequences of acute insult to the central nervous system (CNS). Here, we tested whether an immunization-based treatment that affects the properties of T regulatory cells (Tregs) can reduce brain damage following organophosphate intoxication, as a supplement to the standard antidotal protocol. Rats were intoxicated by acute exposure to the nerve agent soman, or the organophosphate pesticide, paraoxon, and after 24 h were treated with the immunomodulator, poly-YE. A single injection of poly-YE resulted in a significant increase in neuronal survival and tissue preservation. The beneficial effect of poly-YE treatment was associated with specific recruitment of CD4(+) T cells into the brain, reduced microglial activation, and an increase in the levels of brain derived neurotrophic factor (BDNF) in the piriform cortex. These results suggest therapeutic intervention with poly-YE as an immunomodulatory supplementary approach against consequences of organophosphate-induced brain damage.

Advantages of the WRAIR whole blood cholinesterase assay: comparative analysis to the micro-Ellman, Test-mate ChE, and Michel (DeltapH) assays.

Red blood cell AChE (RBC-AChE) and plasma BChE can be used as sensitive biomarkers to detect exposure to OP nerve agents, pesticides, and cholinergic drugs. In a comparative study, RBC-AChE and serum BChE activities in whole blood was obtained from forty seven healthy male and female human volunteers, and then exposed separately ex vivo to three OP nerve agents (soman (GD), sarin (GB) and VX) to generate a wide range of inhibition of AChE and BChE activity (up to 90% of control). These samples were measured using four different ChE assays: (i) colorimetric microEllman (using DTNB at 412 nm), (ii) Test-mate ChE field kit (also based on the Ellman assay), (iii) Michel (delta pH), and (iv) the Walter Reed Army Institute of Research Whole Blood (WRAIR WB) cholinesterase assay. The WRAIR assay is a modified Ellman method using DTP at 324 nm (which minimizes hemoglobin interference and improves sensitivity), and determines AChE and BChE in a small whole blood sample simultaneously. Scatter plots of RBC-AChE activities were determined using the WRAIR ChE assay versus the micro-Ellman, Test-mate and Michel after exposure to varying concentrations of soman, sarin and VX. Regression analyses yielded mostly linear relationships with high correlations (r2 = 0.83-0.93) for RBC-AChE values in the WRAIR assay compared to the alternate methods. For the plasma BChE measurements, individual human values were significantly more variable (as expected), resulting in lower correlations using WRAIR ChE versus the alternate assays (r2 values 0.5 - 0.6). To circumvent the limitations of simple correlation analysis, Bland and Altman analysis for comparing two independent measurement techniques was performed. For example, a Bland and Altman plot of the ratio of the WRAIR whole blood AChE and Michel AChE (plotted on the y-axis) vs. the average of the two methods (x-axis) shows that the majority of the individual AChE values are within +/- 1.96 S.D. of the mean difference, indicating that the two methods may be used interchangeably with a high degree of confidence. The WRAIR ChE assay can be thus be used as a reliable inter-conversion assay when comparing results from laboratory-based (Michel) and field-based (Test-mate ChE kit), which use different methodology and report in different units of AChE activity.

Improvements in the methodology of monitoring sulfur mustard exposure by gas chromatography-mass spectrometry analysis of cleaved and derivatized blood protein adducts.

An analytical method for determining exposure to 2,2'-dichlorodiethyl sulfide (sulfur mustard, HD) has been enhanced. The method is based on the cleavage of adducted HD (protein-hydroxyethylthioethyl esters) to produce thiodiglycol. Following cleavage, a deuterated internal standard is added, and the analytes are extracted, derivatized, and analyzed by gas chromatography-negative ion chemical ionization-mass spectrometry. Inclusion of a concentration step, addition of solid sodium bicarbonate to neutralize excess derivatization reagent, and optimization of method and instrument conditions provided dramatic increases in signal-to-noise ratio. A five-day precision and accuracy study was conducted, including interday and intraday unknown analysis. Linearity was verified by a R(2) > 0.9995 for all five curves evaluated. The precision and accuracy of the assay were demonstrated to be excellent by evaluation of the interday and intraday unknown samples (< 10% relative standard deviation and relative error in most cases). Statistical treatment of the method blanks and calibration results demonstrated a reduction in the limit of quantitation from 25 nM (HD, human plasma, in vitro) to 1.56 nM. Sample and calibration stability through the analytical sequence was established by the inclusion of continuing calibration verification standards (< 5% error). Short-term sample stability was verified by reinjection of a calibration set after 18 days (R(2) = 0.9997). Quantitative agreement with the previous method was supported by the analysis of a 50 nM standard protein sample (HD, rat plasma) with both methodologies (< 1% error).

Analysis of urinary metabolites of sulfur mustard in two individuals after accidental exposure.

In July 2004, two individuals developed blisters after the destruction of a WWI-era munition. To determine the causative agent, urine samples were collected from both the highly blistered patient (patient 1; 6.5% of total body surface area) and patient 2, who had only one small blister. Their urine was analyzed for metabolites of known vesicants including sulfur mustard (HD), Lewisite (L1), and nitrogen mustards. The urine samples only tested positive for metabolites of HD. Additional metabolites were measured to confirm the exposure of sulfur mustard agent HD, including thiodiglycol (TDG), TDG-sulfoxide, and the bis-mercapturate of mustard sulfone. On day 2 after the exposure, patient 1 had a beta-lyase metabolite level of 41 ng/mL, and patient 2 had a level of 2.6 ng/mL. Detectable levels of the beta-lyase metabolite were observed in patient 1 for 11 days and in patient 2 for 7 days. Levels of TDG and both TDG and its sulfoxide measured together in the urine of patient 1 were found to be 24 ng/mL and 50 ng/mL, respectively, on day 2. The bis-mercapturate of mustard sulfone was detected in patient 1 (3.1 ng/mL) on day 2 but was not detected in samples taken on subsequent days.

Gas chromatographic-mass spectrometric analysis of sulfur mustard-plasma protein adducts: validation and use in a rat inhalation model.

Sulfur mustard (HD) is an alkylating agent that reacts rapidly with macromolecular targets resulting in the formation of stable adducts providing depots for markers of exposure. The purpose of this study was to validate an analytical procedure for detection of HD-plasma protein adducts and to establish the utility of the method in an HD rat inhalation study. Calibration curves were prepared in human and rat plasma at six levels of HD (12.5 to 400 nM). Correlation coefficients for the mean data were 0.9987 for human and 0.9992 for rat plasma. The percent coefficient of variation (%CV) derived from the mean concentration data ranged from 0.53 to 14.1% in human (n = 5) and 0.57 to 10.63% in rat (n = 6) plasma. Intraday and interday precision and accuracy studies were conducted at three concentration levels (25, 150, 300 nM) to represent low, medium, and high concentrations of HD relative to those employed in the calibration curve. Precision and accuracy were assessed by determining %CV and % error, respectively. For intra- and interday studies, the %CVs and absolute % errors were less than 15%. The limits of quantitation were 20.88 nM for human and 16.73 nM for rat plasma. In animal studies, rats received nebulized HD at six doses. The data indicate a dose-dependent relationship between maximal plasma concentrations and dose administered (R(2) = 0.9728). Results from this study indicate an accurate, precise, and sensitive method. The method was useful in determining plasma protein adduct formation in a rat inhalation model.

Analysis for plasma protein biomarkers following an accidental human exposure to sulfur mustard.

Following an accidental human exposure to a vesicating agent, plasma samples were analyzed for specific biomarkers of sulfur mustard. One individual suffered chemical burns over 6.5% of the body surface area and required hospitalization; the second individual developed a single, small blister. Plasma specimens from both individuals were examined using two different assays. The first assay targeted sulfur mustard adducts to cysteine-34 of albumin using affinity chromatography, enzyme digestion, and analysis of the alkylated peptide fragment using liquid chromatography-tandem mass spectrometry. The second assay targeted alkylation sites of glutamic and aspartic acids of plasma proteins. Following precipitation of plasma proteins, the sulfur mustard adducts were cleaved from the protein using base, derivatized, and analyzed using gas chromatography-mass spectrometry. Samples obtained over a 42-day period from the individual requiring hospitalization produced positive results for sulfur mustard adducts using both assays. Observed levels of the sulfur mustard biomarker decreased by approximately 75% between days 2 and 42 for both assays. Samples obtained over a six-day period from the individual with a single, small blister produced positive results for the albumin adduct assay. Observed levels were much lower than levels from the hospitalized patient. Blood samples from suspected human exposures to sulfur mustard have only rarely been made available for analysis by sensitive and specific laboratory assays. The data presented here add significantly to the small database of information that currently exists on human biomarkers of sulfur mustard exposure, linking a well-documented exposure event with levels of plasma protein adducts.

Quantification of nerve agent VX-butyrylcholinesterase adduct biomarker from an accidental exposure.

The lack of data in the open literature on human exposure to the nerve agent O-ethyl-S-(2-diisopropylaminoethyl) methylphosphonothioate (VX) gives a special relevance to the data presented in this study in which we report the quantification of VX-butyrylcholinesterase adduct from a relatively low-level accidental human exposure. The samples were analyzed by gas chromatography-high resolution mass spectrometry using the fluoride ion regeneration method for the quantification of multiple nerve agents including VX. Six human plasma samples from the same individual were collected after the patient had been treated once with oxime immediately after exhibiting signs of exposure. Detection limits of approximately 5.5 pg/mL plasma were achieved for the G-analogue of VX (G-VX). Levels of the G-VX ranged from 81.4 pg/mL on the first day after the exposure to 6.9 pg/mL in the sample taken 27 days after the exposure. Based on the reported concentration of human butyrylcholinesterase in plasma of approximately 80 nM, it can be calculated that inhibition levels of >or= 0.05% of BuChE can be accurately quantified. These data further indicate that the fluoride ion regeneration method is a potentially powerful tool that can be used to assess low-level exposure to VX.

Liquid sulfur mustard exposure.

A 35-year-old active duty service member sustained a 6.5% body surface area burn as a result of exposure to the chemical warfare agent sulfur mustard, which is the most severe mustard exposure of a U.S. military member since World War II that is known to us. New techniques were used to demonstrate the detectable persistence of mustard metabolites in the patient's blood for at least 41 days after exposure, validating these techniques for the first time for a human mustard patient; they were also used for the first time with human mustard blister fluid. The techniques extend eightfold the period of time that mustard exposure can be definitively diagnosed, compared with previous techniques. Although this patient's lesions were never life-threatening, he required 2 weeks of intensive burn care. He has been left with ongoing posttraumatic stress disorder and has had an incomplete dermatological recovery. In a major terrorist attack involving many patients exposed to sulfur mustard, care resources would be depleted quickly.

Monitoring sulfur mustard exposure by gas chromatography-mass spectrometry analysis of thiodiglycol cleaved from blood proteins.

A gas chromatography-mass spectrometry method for determining exposure to the chemical warfare agent 2,2'-dichlorodiethyl sulfide (sulfur mustard; HD) has been developed. The technique is based upon quantitating thiodiglycol (TDG) released from blood protein adducts that are formed upon exposure to HD. Protein was precipitated from plasma, whole blood, or packed red blood cells (RBCs) and then treated with sodium hydroxide to liberate protein-bound TDG. The TDG was derivatized with pentafluorobenzoyl chloride that enabled sensitive detection by negative-ion chemical ionization. Octadeuterothiodiglycol was used as an internal standard. Exposure of human plasma to HD (25 nM to 400 nM) resulted in a linear relationship (r2 = 0.9995) between HD concentration and released TDG levels with means ranging from 2.0 to 38 pg/mg protein. The coefficients of variation expressed as a percentage for the data points ranged from 2 to 11.5%. The application of this procedure was demonstrated in two HD animal exposure models. African green monkeys (Chlorocebus aethiops) were exposed intravenously to 1 mg/kg HD, and TDG levels in blood samples were analyzed out to 45 days post-exposure. Mean TDG levels were determined to be 220 pg/mg protein on day 1 and declined to 10 pg/mg protein on day 45. Yorkshire cross pigs (Sus scrofa) were cutaneously exposed to neat liquid HD, and TDG levels in plasma were determined out to 21 days following exposure. Mean TDG levels were found to be 60 pg/mg protein on day one and decreased to an average of 4 pg/mg protein on day 21. The data from this study indicate that the assay is sensitive and provide a relatively simple approach to assay TDG cleaved from blood proteins at relatively long time frames (21-45 days) after HD exposure. The utility of the method has been demonstrated in vivo in a non-human primate and pig HD exposure model.