Microbiological, biological, and chemical weapons of warfare and terrorism

Selection of RNA Aptamers Against Botulinum Neurotoxin Type A Light Chain Through a Non-Radioactive Approach

Botulinum neurotoxin (BoNT), a category A agent, is the most toxic molecule known to mankind. The endopeptidase activity of light chain domain of BoNT is the cause for the inhibition of the neurotransmitter release and the flaccid paralysis that leads to lethality in botulism. Currently, antidotes are not available to reverse the flaccid paralysis caused by BoNT. In the present study, a non-radioactive-based systematic evolution of ligands by exponential enrichment (SELEX) process is developed by utilizing surface plasmon resonance to monitor the binding enrichment. Two RNA aptamers have been identified as strong binders against light chain of botulinum neurotoxin type A. These two aptamers showed strong inhibition activity on LCA, with IC50 in nanomolar range. Inhibition kinetic studies reveal mid nanomolar KI and non-competitive nature of their inhibition, suggesting that they have strong potential as antidotes that can reverse the symptom caused by BoNT/A. More importantly, we observed that the 2'-fluorine-pyrimidine-modified RNA aptamers identified here do not change their binding and biological activities. This observation could lead to a cost-effective way for SELEX, by using regular nucleotide during SELEX, and 2'-fluorine-pyrimidine-modified nucleotide for final application to enhance their RNase-resistance.

Selective and sensitive colorimetric sensor for CN− in the absence and presence of metal ions (Cu2+/Ni2+): mimicking logic gate behaviour

Enone based anion sensors have significance due to their colorimetric reaction upon deprotonation and variable occurrence in the conjugated moiety.

Diverse profiles of ricin-cell interactions in the lung following intranasal exposure to ricin

Ricin, a plant-derived exotoxin, inhibits protein synthesis by ribosomal inactivation. Due to its wide availability and ease of preparation, ricin is considered a biothreat, foremost by respiratory exposure. We examined the in vivo interactions between ricin and cells of the lungs in mice intranasally exposed to the toxin and revealed multi-phasic cell-type-dependent binding profiles. While macrophages (MΦs) and dendritic cells (DCs) displayed biphasic binding to ricin, monophasic binding patterns were observed for other cell types; epithelial cells displayed early binding, while B cells and endothelial cells bound toxin late after intoxication. Neutrophils, which were massively recruited to the intoxicated lung, were refractive to toxin binding. Although epithelial cells bound ricin as early as MΦs and DCs, their rates of elimination differed considerably; a reduction in epithelial cell counts occurred late after intoxication and was restricted to alveolar type II cells only. The differential binding and cell-elimination patterns observed may stem from dissimilar accessibility of the toxin to different cells in the lung and may also reflect unequal interactions of the toxin with different cell-surface receptors. The multifaceted interactions observed in this study between ricin and the various cells of the target organ should be considered in the future development of efficient post-exposure countermeasures against ricin intoxication.

Quantitative Analysis of Staphylococcal Enterotoxins A and B in Food Matrices Using Ultra High-Performance Liquid Chromatography Tandem Mass Spectrometry (UPLC-MS/MS)

A method that uses mass spectrometry (MS) for identification and quantification of protein toxins, staphylococcal enterotoxins A and B (SEA and SEB), in milk and shrimp is described. The analysis was performed using a tryptic peptide, from each of the toxins, as the target analyte together with the corresponding ¹³C-labeled synthetic internal standard peptide. The performance of the method was evaluated by analyzing spiked samples in the quantification range 2.5–30 ng/g (R² = 0.92–0.99). The limit of quantification (LOQ) in milk and the limit of detection (LOD) in shrimp was 2.5 ng/g, for both SEA and SEB toxins. The in-house reproducibility (RSD) was 8%–30% and 5%–41% at different concentrations for milk and shrimp, respectively. The method was compared to the ELISA method, used at the EU-RL (France), for milk samples spiked with SEA at low levels, in the quantification range of 2.5 to 5 ng/g. The comparison showed good coherence for the two methods: 2.9 (MS)/1.8 (ELISA) and 3.6 (MS)/3.8 (ELISA) ng/g. The major advantage of the developed method is that it allows direct confirmation of the molecular identity and quantitative analysis of SEA and SEB at low nanogram levels using a label and antibody free approach. Therefore, this method is an important step in the development of alternatives to the immune-assay tests currently used for staphylococcal enterotoxin analysis.

An integrated logit model for contamination event detection in water distribution systems

The problem of contamination event detection in water distribution systems has become one of the most challenging research topics in water distribution systems analysis. Current attempts for event detection utilize a variety of approaches including statistical, heuristics, machine learning, and optimization methods. Several existing event detection systems share a common feature in which alarms are obtained separately for each of the water quality indicators. Unifying those single alarms from different indicators is usually performed by means of simple heuristics. A salient feature of the current developed approach is using a statistically oriented model for discrete choice prediction which is estimated using the maximum likelihood method for integrating the single alarms. The discrete choice model is jointly calibrated with other components of the event detection system framework in a training data set using genetic algorithms. The fusing process of each indicator probabilities, which is left out of focus in many existing event detection system models, is confirmed to be a crucial part of the system which could be modelled by exploiting a discrete choice model for improving its performance. The developed methodology is tested on real water quality data, showing improved performances in decreasing the number of false positive alarms and in its ability to detect events with higher probabilities, compared to previous studies.

A pyrenesulfonyl-imidazolium derivative as a selective cyanide ion sensor in aqueous media

Unlocking of probe 2 with CN⁻ ions leads to its minimum detection limit of 0.5 μM (13 ppb).

Clostridium perfringens epsilon toxin: the third most potent bacterial toxin known

Epsilon toxin (ETX) is produced by Clostridium perfringens type B and D strains and causes enterotoxemia, a highly lethal disease with major impacts on the farming of domestic ruminants, particularly sheep. ETX belongs to the aerolysin-like pore-forming toxin family. Although ETX has striking similarities to other toxins in this family, ETX is often more potent, with an LD50 of 100 ng/kg in mice. Due to this high potency, ETX is considered as a potential bioterrorism agent and has been classified as a category B biological agent by the Centers for Disease Control and Prevention (CDC) of the United States. The protoxin is converted to an active toxin through proteolytic cleavage performed by specific proteases. ETX is absorbed and acts locally in the intestines then subsequently binds to and causes lesions in other organs, including the kidneys, lungs and brain. The importance of this toxin for veterinary medicine and its possible use as a biological weapon have drawn the attention of researchers and have led to a large number of studies investigating ETX. The aim of the present work is to review the existing knowledge on ETX from C. perfringens type B and D.

Novel salicylaldehyde derivatives as fluorescence turn-on sensors for cyanide ion

A novel series of fluorescent probes containing diphenylacetylene as fluorogenic units and salicylaldehyde as a CN(-) receptor were successfully synthesized by using sonogashira coupling. In the presence of Triton-X 100 non-ionic surfactant, the fluorophores exhibited fluorescence "turn-on" in response to CN(-) in aqueous media with the detection limit of 1.6 μM. The turn-on signal is the result of the conversion of the aldehyde to cyanohydrin via the internal acid catalyzed addition of cyanide. Using paper sensor strips, a naked eye detection of cyanide is possible down to 5 nmol.

A critical review of anaesthetised animal models and alternatives for military research, testing and training, with a focus on blast damage, haemorrhage and resuscitation

Military research, testing, and surgical and resuscitation training, are aimed at mitigating the consequences of warfare and terrorism to armed forces and civilians. Traumatisation and tissue damage due to explosions, and acute loss of blood due to haemorrhage, remain crucial, potentially preventable, causes of battlefield casualties and mortalities. There is also the additional threat from inhalation of chemical and aerosolised biological weapons. The use of anaesthetised animal models, and their respective replacement alternatives, for military purposes -- particularly for blast injury, haemorrhaging and resuscitation training -- is critically reviewed. Scientific problems with the animal models include the use of crude, uncontrolled and non-standardised methods for traumatisation, an inability to model all key trauma mechanisms, and complex modulating effects of general anaesthesia on target organ physiology. Such effects depend on the anaesthetic and influence the cardiovascular system, respiration, breathing, cerebral haemodynamics, neuroprotection, and the integrity of the blood-brain barrier. Some anaesthetics also bind to the NMDA brain receptor with possible differential consequences in control and anaesthetised animals. There is also some evidence for gender-specific effects. Despite the fact that these issues are widely known, there is little published information on their potential, at best, to complicate data interpretation and, at worst, to invalidate animal models. There is also a paucity of detail on the anaesthesiology used in studies, and this can hinder correct data evaluation. Welfare issues relate mainly to the possibility of acute pain as a side-effect of traumatisation in recovered animals. Moreover, there is the increased potential for animals to suffer when anaesthesia is temporary, and the procedures invasive. These dilemmas can be addressed, however, as a diverse range of replacement approaches exist, including computer and mathematical dynamic modelling of the human body, cadavers, interactive human patient simulators for training, in vitro techniques involving organotypic cultures of target organs, and epidemiological and clinical studies. While the first four of these have long proven useful for developing protective measures and predicting the consequences of trauma, and although many phenomena and their sequelae arising from different forms of trauma in vivo can be induced and reproduced in vitro, non-animal approaches require further development, and their validation and use need to be coordinated and harmonised. Recommendations to these ends are proposed, and the scientific and welfare problems associated with animal models are addressed, with the future focus being on the use of batteries of complementary replacement methods deployed in integrated strategies, and on greater transparency and scientific cooperation.

Proteomic study of differential protein expression in mouse lung tissues after aerosolized ricin poisoning

Ricin is one of the most poisonous natural toxins from plants and is classified as a Class B biological threat pathogen by the Centers for Disease Control and Prevention (CDC) of U.S.A. Ricin exposure can occur through oral or aerosol routes. Ricin poisoning has a rapid onset and a short incubation period. There is no effective treatment for ricin poisoning. In this study, an aerosolized ricin-exposed mouse model was developed and the pathology was investigated. The protein expression profile in the ricin-poisoned mouse lung tissue was analyzed using proteomic techniques to determine the proteins that were closely related to the toxicity of ricin. 2D gel electrophoresis, mass spectrometry and subsequent biological functional analysis revealed that six proteins including Apoa1 apolipoprotein, Ywhaz 14-3-3 protein, Prdx6 Uncharacterized Protein, Selenium-binding protein 1, HMGB1, and DPYL-2, were highly related to ricin poisoning.

Acute toxicity of some nerve agents and pesticides in rats

OBJECTIVES

Highly toxic organophosphorus compounds (V- and G-nerve agents) were originally synthesized for warfare or as agricultural pesticides. Data on their acute toxicity are rare and patchy. Therefore, there is a need for integrated summary comparing acute toxicity of organophosphates using different administration routes in the same animal model with the same methodology. Based on original data, a summary of in vivo acute toxicity of selected V- and G-nerve agents (tabun, sarin, soman, VX, Russian VX) and organophosphates paraoxon (POX) and diisopropyl fluorophosphate (DFP) in rats has been investigated.

MATERIALS AND METHODS

Male Wistar rats were exposed to organophosphates in several administration routes (i.m., i.p., p.o, s.c., p.c.). The acute toxicity was evaluated by the assessment of median lethal dose (LD50, mg kg(-1)) 2, 4, and 24 hours post exposure.

RESULTS

V-agents were the most toxic presented with LD50 ranged from 0.0082 mg kg(-1) (VX, i.m.) to 1.402 mg kg(-1) (Russian VX, p.o.), followed by G-agents (LD50 = 0.069 mg kg(-1)/soman, i.m./ - 117.9 mg kg(-1)/sarin, p.c./), organophosphate POX and DFP (LD50 = 0.321 mg kg(-1)/POX, i.m./ - 420 mg kg(-1)/DFP, p.c./). Generally, i.m. administration was the most toxic throughout all tested agents and ways of administration (LD50 = 0.0082 mg kg(-1)/VX/ - 1.399 mg kg(-1)/DFP/) whereas p.c. way was responsible for lowest acute toxicity (LD50 = 0.085 mg kg(-1)/VX/ - 420 mg kg(-1)/DFP/).

CONCLUSION

The acute toxicity of selected organophosphorus compounds is summarized throughout this study. Although the data assessed in rats are rather illustrative prediction for human, it presents a valuable contribution, indicating the toxic potential and harmfulness of organophosphates.

Cross-species and tissue variations in cyanide detoxification rates in rodents and non-human primates on protein-restricted diet

We sought to elucidate the impact of diet, cyanide or cyanate exposure on mammalian cyanide detoxification capabilities (CDC). Male rats (~8 weeks old) (N=52) on 75% sulfur amino acid (SAA)-deficient diet were treated with NaCN (2.5mg/kg bw) or NaOCN (50mg/kg bw) for 6 weeks. Macaca fascicularis monkeys (~12 years old) (N=12) were exclusively fed cassava for 5 weeks. CDC was assessed in plasma, or spinal cord, or brain. In rats, NaCN induced seizures under SAA-restricted diet whereas NaOCN induced motor deficits. No deficits were observed in non-human primates. Under normal diet, the CDC were up to ~80× faster in the nervous system (14 ms to produce one μmol of thiocyanate from the detoxification of cyanide) relative to plasma. Spinal cord CDC was impaired by NaCN, NaOCN, or SAA deficiency. In M. fascicularis, plasma CDC changed proportionally to total proteins (r=0.43; p<0.001). The plasma CDC was ~2× relative to that of rodents. The nervous system susceptibility to cyanide may result from a "multiple hit" by the toxicity of cyanide or its cyanate metabolite, the influences of dietary deficiencies, and the tissue variations in CDC. Chronic dietary reliance on cassava may cause metabolic derangement including poor CDC.

Addressing bioterrorism concerns: options for investigating the mechanism of action of Staphylococcus aureus enterotoxin B

Staphylococcal enterotoxin B (SEB) is of concern to military and civilian populations as a bioterrorism threat agent. It is a highly potent toxin produced by Staphylococcus aureus and is stable in storage and under aerosolisation; it is able to produce prolonged highly incapacitating illness at very low-inhaled doses and death at elevated doses. Concerns regarding SEB are compounded by the lack of effective medical countermeasures for mass treatment of affected populations. This article considers the mechanism of action of SEB, the availability of appropriate experimental models for evaluating the efficacy of candidate medical countermeasures with particular reference to the need to realistically model SEB responses in man and the availability of candidate countermeasures (with an emphasis on commercial off-the-shelf options). The proposed in vitro approaches would be in keeping with Dstl’s commitment to reduction, refinement and replacement of animal models in biomedical research, particularly in relation to identifying valid alternatives to the use of nonhuman primates in experimental studies.

The Immediate Pulmonary Disease Pattern following Exposure to High Concentrations of Chlorine Gas

Background. Classification of pulmonary disease into obstructive, restrictive, and mixed patterns is based on 2005 ATS/ERS guidelines and modified GOLD criteria by Mannino et al. (2003), but these guidelines are of limited use for simple spirometry in situations involving mass casualties. Aim. The purpose of this study was to apply these guidelines to patients who underwent simple spirometry following high concentration of chlorine gas inhalation after a train derailment in Graniteville, South Carolina. Methods. We retrospectively investigated lung functions in ten patients. In order to classify pulmonary disease pattern, we used 2005 ATS/ERS guidelines and modified GOLD criteria along with our own criteria developed using available simple spirometry data. Results. We found predominant restrictive pattern in our patients with both modified GOLD and our criteria, which is in contrast to other chlorine exposure studies where obstructive pattern was more common. When compared to modified GOLD and our criteria, 2005 ATS/ERS guidelines underestimated the frequency of restrictive disease. Conclusion. Diagnosis of pulmonary disease patterns is of importance after irritant gas inhalation. Acceptable criteria need to be developed to evaluate pulmonary disease through simple spirometry in events leading to mass casualty and patient surge in hospitals.

RNA aptasensor for rapid detection of natively folded type A botulinum neurotoxin

A surface plasmon resonance based RNA aptasensor for rapid detection of natively folded type A botulinum neurotoxin is reported. Using detoxified recombinant type A botulinum neurotoxin as the surrogate, the aptasensor detects active toxin within 90 min. The detection limit of the aptasensor in phosphate buffered saline, carrot juice, and fat free milk is 5.8 ng/ml, 20.3 ng/ml and 23.4 ng/ml, respectively, while that in 5-fold diluted human serum is 22.5 ng/ml. Recovery of toxin from disparate sample matrices are within 91-116%. Most significant is the ability of this aptasensor to effectively differentiate the natively folded toxin from denatured, inactive toxin, which is important for homeland security surveillance and threat assessment. The aptasensor is stable for more than 30 days and over 400 injections/regeneration cycles. Such an aptasensor holds great promise for rapid detection of active botulinum neurotoxin for field surveillance due to its robustness, stability and reusability.

Creation of catalytic antibodies metabolizing organophosphate compounds

Development of new ways of creating catalytic antibodies possessing defined substrate specificity towards artificial substrates has important fundamental and practical aspects. Low immunogenicity combined with high stability of immunoglobulins in the blood stream makes abzymes potent remedies. A good example is the cocaine-hydrolyzing antibody that has successfully passed clinical trials. Creation of an effective antidote against organophosphate compounds, which are very toxic substances, is a very realistic goal. The most promising antidotes are based on cholinesterases. These antidotes are now expensive, and their production methods are inefficient. Recombinant antibodies are widely applied in clinics and have some advantage compared to enzymatic drugs. A new potential abzyme antidote will combine effective catalysis comparable to enzymes with high stability and the ability to switch on effector mechanisms specific for antibodies. Examples of abzymes metabolizing organophosphate substrates are discussed in this review.

Attack of the nervous system by Clostridium perfringens Epsilon toxin: from disease to mode of action on neural cells

Epsilon toxin (ET), produced by Clostridium perfringens types B and D, ranks among the four most potent poisonous substances known so far. ET-intoxication is responsible for enterotoxaemia in animals, mainly sheep and goats. This disease comprises several manifestations indicating the attack of the nervous system. This review aims to summarize the effects of ET on central nervous system. ET binds to endothelial cells of brain capillary vessels before passing through the blood-brain barrier. Therefore, it induces perivascular oedema and accumulates into brain. ET binding to different brain structures and to different component in the brain indicates regional susceptibility to the toxin. Histological examination has revealed nerve tissue and cellular lesions, which may be directly or indirectly caused by ET. The naturally occurring disease caused by ET-intoxication can be reproduced experimentally in rodents. In mice and rats, ET recognizes receptor at the surface of different neural cell types, including certain neurons (e.g. the granule cells in cerebellum) as well as oligodendrocytes, which are the glial cells responsible for the axons myelination. Moreover, ET induces release of glutamate and other transmitters, leading to firing of neural network. The precise mode of action of ET on neural cells remains to be determined.

A dynamic thresholds scheme for contaminant event detection in water distribution systems

In this study, a dynamic thresholds scheme is developed and demonstrated for contamination event detection in water distribution systems. The developed methodology is based on a recently published article of the authors (Perelman et al., 2012). Event detection in water supply systems is aimed at disclosing abnormal hydraulic or water quality events by exploring the time series behavior of routine hydraulic (e.g., flow, pressure) and water quality measurements (e.g., residual chlorine, pH, turbidity). While event detection raises alerts to the possibility of an event occurrence, it does not relate to origins, thus an event may be hydraulically-driven, as a consequence of problems like sudden leakages or pump/pipe malfunctions. Most events, however, are related to deliberate, accidental, or natural contamination intrusions. The developed methodology herein is based on off-line and on-line stages. During the off-line stage, a genetic algorithm (GA) is utilized for tuning five decision variables: positive and negative filters, positive and negative dynamic thresholds, and window size. During the on-line stage, a recursively Bayes' rule is invoked, employing the five decision variables, for real time on-line event detection. Using the same database, the proposed methodology is compared to Perelman et al. (2012), showing considerably improved detection ability. Metadata and the computer code are provided as Supplementary material.

Paclitaxel is an inhibitor and its boron dipyrromethene derivative is a fluorescent recognition agent for botulinum neurotoxin subtype A

We have successfully identified one new inhibitor and one new fluorescent recognition agent for the botulinum neurotoxin subtype A (BoNT/A) using the virtual screening protocol "protein scanning with virtual ligand screening" (PSVLS). Hit selection used an in-house developed holistic binding scoring method. Selected hits were tested experimentally for inhibitory activity using fluorescence resonance energy transfer (FRET) assays against the light chain (catalytic domain) of BoNT/A. Ligand binding was determined against the light and heavy chain BoNT/A complex through either radiolabeled ligand binding assays (nonfluorescent ligands) or fluorescence intensity assays (fluorescent ligands). These experimental assays have confirmed one compound (paclitaxel) to inhibit BoNT/A's proteolytic activity experimentally with an IC50 of 5.2 μM. A fluorescent derivative was also confirmed to bind to the toxin and therefore is a suitable candidate for the rational design of new detection agents and for the development of fluorescence-based multiprobe detection assays.

Salivary levels of secretary IgA, C5a and alpha 1-antitrypsin in sulfur mustard exposed patients 20 years after the exposure, Sardasht-Iran Cohort Study (SICS)

Sulfur mustard (SM) is a strong toxic agent that causes acute and chronic health effects on a myriad of organs following exposure. Although the primary targets of inhaled mustard gas are the epithelia of the upper respiratory tract, the lower respiratory tract is the focus of the current study, and upper tract complications remain obscure. To our knowledge there is no study addressing the secretory IgA (S-IgA), C5a, alpha 1 antitrypsin (A1AT) in the saliva of SM-exposed victims. In this study, as many as 500 volunteers, including 372 SM-exposed cases and 128 control volunteers were recruited. A 3 ml sample of saliva was collected from each volunteer, and the level of secretory IgA, C5a, and alpha 1 antitrypsin in the samples were compared between the two groups. The SM-exposed group showed a significantly higher amount of salivary alpha 1 antitrypsin and secretary IgA compared to the control group (p<.006 and p<.018 respectively). The two groups showed no significant difference (p=0.192) in the level of C5a. The results also showed that the level of salivary A1AT is more than that of IgA in severely injured cases. The findings presented here provide valuable insight for both researchers and practitioners dealing with victims of the chemical warfare agent, sulfur mustard. This research indicates that certain branches of the inflammatory processes mandate serious attention in therapeutic interventions.

Medical aspects of bio-terrorism

INTRODUCTION

Bioterrorism is a terrorist action involving the intentional release or dissemination of a biological warfare agent (BWA), which includes some bacteria, viruses, rickettsiae, fungi or biological toxins. BWA is a naturally occurring or human-modified form that may kill or incapacitate humans, animals or plants as an act of war or terrorism. BWA is a weapon of choice for mass destruction and terrorism, because of the incubation period, less effective amount than chemical warfare agents, easily distribution, odorless, colorless, difficult to detect, no need of specialized equipment for production and naturally distribution which can easily be obtained. BWA may be disseminating as an aerosol, spray, explosive device, and by food or water.

CLASSIFICATION

Based on the risk for human health, BWAs have been prioritized into three categories of A, B and C. Category A includes microorganisms or toxins that easily spread, leading to intoxication with high death rates such as Anthrax, Botulism, Plague, Smallpox, Tularemia and Viral hemorrhagic fevers. Category B has lower toxicity with wider range, including Staphylococcal Entrotoxin type B (SEB), Epsilon toxin of Clostridium perfringens, Ricin, Saxotoxins, Abrin and Trichothecene mycotoxins. The C category includes emerging pathogens that could also be engineered for mass spread such as Hanta viruses, multidrug-resistant tuberculosis, Nipah virus, the tick-borne encephalitis viruses, hemorrhagic fever viruses and yellow fever. CLINICAL MANIFESTATIONS OF BIOTOXINS IN HUMAN: Clinical features and severity of intoxication depend on the agent and exposed dose, route of entry, individual variation and environmental factors. Onset of symptoms varies from 2-24 h in Ricin to 24-96 h in Botulism. Clinical manifestations also vary from irritation of the eyes, skin and mucus membranes in T2 toxin to an acute flaccid paralysis of bilateral cranial nerve impairment of descending manner in botulism. Most of the pyrogenic toxins such as SEB produce the same signs and symptoms as toxic shock syndrome including a rapid drop in blood pressure, elevated temperature, and multiple organ failure.

MANAGEMENT

There is no specific antidote or effective treatment for most of the biotoxins. The clinical management is thus more supportive and symptomatic. Fortunately vaccines are now available for most of BWA. Therefore, immunization of personnel at risk of exposure is recommended.

CONCLUSION

Biotoxins are very wide and bioterrorism is a heath and security threat that may induce national and international problems. Therefore, the security authorities, health professional and even public should be aware of bioterrorism.

Toxicity of ricin toxin A chain in rats

Ricin toxin A chain (RTA) is the cytotoxic component of the dimeric protein, ricin, one of the most potent and deadly plant toxins extracted from the seeds of Ricinus communis. RTA has been investigated as a potential candidate for cancer chemotherapy, in the form of immunotoxins, and as a method for depleting macrophages in vivo. The toxicity of RTA immunotoxins is mostly characterized by inflammation and necrosis and has been attributed to the RTA moiety of the conjugate. The present study was carried out to investigate the toxicity of intravenously (i.v.) administered RTA alone and to assess whether the observed tissue injuries are associated with increases in oxidative stress (OS) and inflammation. RTA (10 or 90 µg/kg body weight) was administered to animals i.v., and 5 or 24 hours later, liver, lungs, kidneys, and hearts were examined. RTA, at a dose of 90 µg/kg (i.v.), resulted in significant increases (P < 0.05) in an inflammatory response (i.e., increases in hepatic and lung myeloperoxidase activity) and increases in oxidant response (increases in lipid peroxidation and decreases in glutathione levels in hepatic and lung homogenates). These data suggest that i.v. administration of RTA resulted in organ injuries that were associated with inflammation and OS.

Terrorism Involving Cyanide: The Prospect of Improving Preparedness in the Prehospital Setting

The potential for domestic or international terrorism involving cyanide has not diminished and in fact may have increased in recent years. This paper discusses cyanide as a terrorist weapon and the current state of readiness for a cyanide attack in the United States. Many of the factors that render cyanide appealing to terrorists are difficult to modify sufficiently to decrease the probability of a cyanide attack. For example, the relative ease with which cyanide can be used as a weapon without special training, its versatile means of delivery to intended victims, and to a large degree, its ready availability cannot be significantly modified through preparedness efforts. On the other hand, the impact of an attack can be mitigated through preparedness measures designed to minimize the physical, psychological, and social consequences of cyanide exposure. Although the nation remains ill-equipped to manage a cyanide disaster, significant progress is being realized in some aspects of preparedness. Hydroxocobalamin—a cyanide antidote that may be appropriate for use in the prehospital setting for presumptive cases of cyanide poisoning—currently is under development for potential introduction in the US. If it becomes available in the US, hydroxocobalamin could enhance the role of the prehospital emergency responder in providing care to victims of a cyanide disaster. Additional progress is required in the areas of ensuring local and regional availability of antidotal treatment and supportive interventions, educating emergency healthcare providers about cyanide poisoning and its management, and raising public awareness of the potential for a cyanide attack and how to respond.

Rapid and simple DNA extraction method for the detection of enterotoxigenic Staphylococcus aureus directly from food samples: comparison of PCR and LAMP methods

AIMS

  The study describes the development of simple and rapid DNA extraction method in combination with loop-mediated isothermal amplification (LAMP) to detect enterotoxigenic Staphylococcus aureus in food samples.

METHODS AND RESULTS

  In this study, isolation of genomic DNA of enterotoxigenic Staph. aureus from spiked milk, milk burfi, khoa, sugarcane juice and boiled rice was carried out by boiling the isolated sample pellets for 10 min with 1% Triton X-100. The isolated DNA was evaluated by polymerase chain reaction (PCR) and LAMP method. The LAMP was found to be 100 times more sensitive than PCR. The LAMP assay was very specific for Staph. aureus, and the presence of other contaminating bacterial DNAs and food matrix did not interfere or inhibit the LAMP assay.

CONCLUSIONS

  The template DNA extraction method developed in this study for food samples is simple, rapid and cost-effective. LAMP was found to be less sensitive to matrix effect of food, compared to PCR.

SIGNIFICANCE AND IMPACT OF THE STUDY

  The method is suitable for direct detection of Staph. aureus without any enrichment in contaminated food samples and hence finds its application in food safety analysis, in permutation with LAMP.

Treatment of neuroterrorism

Bioterrorism is defined as the intentional use of biological, chemical, nuclear, or radiological agents to cause disease, death, or environmental damage. Early recognition of a bioterrorist attack is of utmost importance to minimize casualties and initiate appropriate therapy. The range of agents that could potentially be used as weapons is wide, however, only a few of these agents have all the characteristics making them ideal for that purpose. Many of the chemical and biological weapons can cause neurological symptoms and damage the nervous system in varying degrees. Therefore, preparedness among neurologists is important. The main challenge is to be cognizant of the clinical syndromes and to be able to differentiate diseases caused by bioterrorism from naturally occurring disorders. This review provides an overview of the biological and chemical warfare agents, with a focus on neurological manifestation and an approach to treatment from a perspective of neurological critical care.

Mass casualties and health care following the release of toxic chemicals or radioactive material--contribution of modern biotechnology

Catastrophic chemical or radiological events can cause thousands of casualties. Such disasters require triage procedures to identify the development of health consequences requiring medical intervention. Our objective is to analyze recent advancements in biotechnology for triage in mass emergency situations. In addition to identifying persons "at risk" of developing health problems, these technologies can aid in securing the unaffected or "worried well". We also highlight the need for public/private partnerships to engage in some of the underpinning sciences, such as patho-physiological mechanisms of chemical and radiological hazards, and for the necessary investment in the development of rapid assessment tools through identification of biochemical, molecular, and genetic biomarkers to predict health effects. For chemical agents, biomarkers of neurotoxicity, lung damage, and clinical and epidemiological databases are needed to assess acute and chronic effects of exposures. For radiological exposures, development of rapid, sensitive biomarkers using advanced biotechnologies are needed to sort exposed persons at risk of life-threatening effects from persons with long-term risk or no risk. The final implementation of rapid and portable diagnostics tools suitable for emergency care providers to guide triage and medical countermeasures use will need public support, since commercial incentives are lacking.

Time-dependent botulinum neurotoxin serotype A metalloprotease inhibitors

Botulinum neurotoxins (BoNTs) are the most lethal of biological substances, and are categorized as class A biothreat agents by the Centers for Disease Control and Prevention. There are currently no drugs to treat the deadly flaccid paralysis resulting from BoNT intoxication. Among the seven BoNT serotypes, the development of therapeutics to counter BoNT/A is a priority (due to its long half-life in the neuronal cytosol and its ease of production). In this regard, the BoNT/A enzyme light chain (LC) component, a zinc metalloprotease responsible for the intracellular cleavage of synaptosomal-associated protein of 25 kDa, is a desirable target for developing post-BoNT/A intoxication rescue therapeutics. In an earlier study, we reported the high throughput screening of a library containing 70,000 compounds, and uncovered a novel class of benzimidazole acrylonitrile-based BoNT/A LC inhibitors. Herein, we present both structure-activity relationships and a proposed mechanism of action for this novel inhibitor chemotype.

Receptor mimicry as novel therapeutic treatment for biothreat agents

The specter of intentional release of pathogenic microbes and their toxins is a real threat. This article reviews the literature on adhesins of biothreat agents, their interactions with oligosaccharides and the potential for anti-adhesion compounds as an alternative to conventional therapeutics. The minimal binding structure of ricin has been well characterised and offers the best candidate for successful anti-adhesion therapy based on the Galβ1-4GlcNAc structure. The botulinum toxin serotypes A-F bind to a low number of gangliosides (GT1b, GQ1b, GD1a and GD1b) hence it should be possible to determine the minimal structure for binding. The minimal disaccharide sequence of GalNAcβ1-4Gal found in the gangliosides asialo-GM1 and asialo-GM2 is required for adhesion for many respiratory pathogens. Although a number of adhesins have been identified in bacterial biothreat agents such as Yersinia pestis, Bacillus anthracis, Francisella tularensis, Brucella species and Burkholderia pseudomallei, specific information regarding their in vivo expression during pneumonic infection is lacking. Limited oligosaccharide inhibition studies indicate the potential of GalNAcβ1-4Gal, GalNAcβ-3Gal and the hydrophobic compound, para-nitrophenol as starting points for the rational design of generic anti-adhesion compounds. A cocktail of multivalent oligosaccharides based on the minimal binding structures of identified adhesins would offer the best candidates for anti-adhesion therapy.

Small molecule inhibitors as countermeasures for botulinum neurotoxin intoxication

Botulinum neurotoxins (BoNTs) are the most potent of known toxins and are listed as category A biothreat agents by the U.S. CDC. The BoNT-mediated proteolysis of SNARE proteins inhibits the exocytosis of acetylcholine into neuromuscular junctions, leading to life-threatening flaccid paralysis. Currently, the only therapy for BoNT intoxication (which results in the disease state botulism) includes experimental preventative antibodies and long-term supportive care. Therefore, there is an urgent need to identify and develop inhibitors that will serve as both prophylactic agents and post-exposure ‘rescue’ therapeutics. This review focuses on recent progress to discover and develop small molecule inhibitors as therapeutic countermeasures for BoNT intoxication.