Evaluation of Handheld Assays for the Detection of Ricin and Staphylococcal Enterotoxin B in Disinfected Waters

Development of a rapid field test is needed capable of determining if field supplies of water are safe to drink by the warfighter during a military operation. The present study sought to assess the effectiveness of handheld assays (HHAs) in detecting ricin and Staphylococcal Enterotoxin B (SEB) in water. Performance of HHAs was evaluated in formulated tap water with and without chlorine, reverse osmosis water (RO) with chlorine, and RO with bromine. Each matrix was prepared, spiked with ricin or SEB at multiple concentrations, and then loaded onto HHAs. HHAs were allowed to develop and then read visually. Limits of detection (LOD) were determined for all HHAs in each water type. Both ricin and SEB were detected by HHAs in formulated tap water at or below the suggested health effect levels of 455 ng/mL and 4.55 ng/mL, respectively. However, in brominated or chlorinated waters, LODs for SEB increased to approximately 2,500 ng/mL. LODs for ricin increased in chlorinated water, but still remained below the suggested health effect level. In brominated water, the LOD for ricin increased to approximately 2,500 ng/mL. In conclusion, the HHAs tested were less effective at detecting ricin and SEB in disinfected water, as currently configured

Lactate Dehydrogenase Kinetics and Inhibition using a Microplate Reader

A lactate dehydrogenase (LDH) enzyme kinetics lab. expt. has been developed in which students obtain kinetic data using a microplate spectrophotometer (reader). These instruments have the capability of reading absorbances of many samples in a very short time frame. In this expt. 12 samples are prepd. at a time and the absorbances read in less than 1 min. In a 3-h lab. period, students collect data at five different substrate concns. without inhibitor and also in the presence of two different concns. of inhibitor. Students have enough time to repeat each part if they obtain too much scatter in their data. The enzyme examd., LDH, correlates with the study of metab. and has particular relevance for students who are interested in medical careers. The LDH assay itself is not new, but the microplate format and the use of urea as a quench reagent are novel features. Students plot Michaelis-Menten and Lineweaver-Burk plots and calc. values for Vmax, apparent Vmax (Vappmax), Km, apparent Km (Kappm), kcat, and kl. Students typically obtain results correctly showing that oxalic acid is a competitive inhibitor and oxamic acid is a noncompetitive inhibitor when lactate is the substrate of the reaction

Further Studies into the Feasibility of Using Aqueous Alum Solutions in the Destruction of VX

The destruction of phosphorus based chemical warfare agents using aqueous buffer mixtures of aluminum sulfate (alum) and sodium aluminate is pursued. The production of VX (O-ethyl-S-[2-(diisopropylamino)ethyl]-methylphos-phonothiolate) hydrolysis products ethyl methyl phosphonic acid (EMPA), an aluminum complex of EMPA, and S-[2-(diisopropylamino)ethyl]methylphosphonothiolate (EA-2192) is characterized in acidic and basic alum buffers. The study employs ^{31}P high resolution magic angle nuclear magnetic resonance spectroscopy (HRMAS NMR) for both quantitative and qualitative analysis. The acidic buffer results in a slower reaction rate and is less effective than the basic buffer

Aluminum Sulfate and Sodium Aluminate Buffer Solutions for the Destruction of Phosphorus Based Chemical Warfare Agents

Nerve agents VX and GB (sarin) are sequestered and removed by aluminum sulfate and sodium aluminate mixts. adjusted to pH 4 in soln. The products of hydrolysis are removed with the alum floc below NMR detection limits over time depending and the amt. of aluminum molar excess relative to agent. Half-lives for GB decompn. are 3.1 h and 1.1 h, resp., for a 120 and a 1200 M excess. For VX, the half-lives are 8.5 d and 2.9 d for a 240 and a 5000 M aluminum excess. In the case of GB, fluorine is sequestered as the hexafluoroaluminate ion. In the case of VX, no phosphorus contg. hydrolysis products including the very toxic S-[2-(diisopropyl-amino)-ethyl]methylphosphonothiolate (EA-2192) are detected in the hydrolyzate

Main Group Metal Halide Complexes with Sterically Hindered Thioureas: Part XVII. The Crystal and Molecular Structures of Two New Tellurium Chloride Complexes with 1,3-dimethyl-2(3H)-imidazolethione

In an attempt to determine the crystal and molecular structure of previously reported [TeCl2(dmit)4] (1) [dmit=1,3-dimethyl-2(3H)-imidazolethione], recrystallization in hot acetonitrile yielded two new complexes, [TeCl2(dmit)2] (2) and [TeCl4(dmit)2] (3) as determined by X-ray crystallography. The structure of 2 consists of a cis-substituted square planar geometry with the thione rings both oriented on the same side of the TeS2Cl2 plane. The complex undergoes very slow decomposition in air. The structure of 3 is a near-octahedral arrangement with the thione ligands trans to each othe

1-Methyl-3-alkyl-2(3H)imidazolethione Complexes of Metal Halides: A Thematic-Ligand Approach to Involve Undergraduates in Research Projects

A method used to attract undergraduates into research projects is described. The method incorporates the thematic ligand approach using a class of thiourea-type ligands known as 1-methyl-3-alkyl-2(3H)-imidazotethiones to make new metal and nonmetal halide addn. products. A related selenium analog and a bidentate thione are also employed in the process, which to date has produced 24 new compds. The students start the work as a team research project in an intermediate inorg. synthesis lab. course by first making the ligand and then its addn. product which is characterized by std. methods during the course. Many of the attempts are failures, but teams that produce new compds. often go on to research projects that result in further structural characterization through collaborative efforts with the Georgia Institute of Technol. or with Clemson University. A case study involving the synthesis and characterization of 1-methyl-3-(2-propyl)-imidazole-2(3H)-thione (mipit) and its bismuth trichloride adduct, BiCl3 (mipit)2 is presented

Collaboration between Chemistry and Biology to Introduce Spectroscopy, Electrophoresis, and Molecular Biology as Tools for Biochemistry

Focuses on the collaboration between chemistry and biology to introduce spectroscopy, electrophoresis and molecular biology as of for biochemistry. Quantification of the hormone abscidic acid in plant tissues; Methods for determining protein concentration; Amount of reduced nicotinamide adenine dinucleotide co-factor

Main Group Metal Halide Complexes with Sterically Hindered Thioureas. XVI. The Synthesis, Characterization, and Crystal Structures of Two New Complexes Of 1,3-dimethyl-2(3H)-imidazolethione with Indium Trihalides

In an attempt to prep. complexes analogous to the bis-dmit adducts of Group 15 trihalides [dmit = 1,3-dimethyl-2(3H)-imidazolethione], In(dmit)2X3 (X = Cl, Br) were synthesized and characterized. The crystal and mol. structures for both of these compds. showed a distorted trigonal bipyramidal configuration with the thiones and one halide occupying equatorial positions and the two remaining halides arranged in a near-linear X-In-X axial grouping (X = Cl, Br). This stands in contrast to the dimeric distorted octahedral structures obsd. for BiCl3(dmit)2 and SbCl3(dmit)2. The far-IR and laser-Raman spectra as well as soln. state proton and solid state 13C NMR spectra are reported

Incidence of severe critical events in paediatric anaesthesia (APRICOT): a prospective multicentre observational study in 261 hospitals in Europe

Background Little is known about the incidence of severe critical events in children undergoing general anaesthesia in Europe. We aimed to identify the incidence, nature, and outcome of severe critical events in children undergoing anaesthesia, and the associated potential risk factors. Methods The APRICOT study was a prospective observational multicentre cohort study of children from birth to 15 years of age undergoing elective or urgent anaesthesia for diagnostic or surgical procedures. Children were eligible for inclusion during a 2-week period determined prospectively by each centre. There were 261 participating centres across 33 European countries. The primary endpoint was the occurence of perioperative severe critical events requiring immediate intervention. A severe critical event was defined as the occurrence of respiratory, cardiac, allergic, or neurological complications requiring immediate intervention and that led (or could have led) to major disability or death. This study is registered with ClinicalTrials.gov, number NCT01878760. Findings Between April 1, 2014, and Jan 31, 2015, 31â127 anaesthetic procedures in 30â874 children with a mean age of 6·35 years (SD 4·50) were included. The incidence of perioperative severe critical events was 5·2% (95% CI 5·0â5·5) with an incidence of respiratory critical events of 3·1% (2·9â3·3). Cardiovascular instability occurred in 1·9% (1·7â2·1), with an immediate poor outcome in 5·4% (3·7â7·5) of these cases. The all-cause 30-day in-hospital mortality rate was 10 in 10â000. This was independent of type of anaesthesia. Age (relative risk 0·88, 95% CI 0·86â0·90; p<0·0001), medical history, and physical condition (1·60, 1·40â1·82; p<0·0001) were the major risk factors for a serious critical event. Multivariate analysis revealed evidence for the beneficial effect of years of experience of the most senior anaesthesia team member (0·99, 0·981â0·997; p<0·0048 for respiratory critical events, and 0·98, 0·97â0·99; p=0·0039 for cardiovascular critical events), rather than the type of health institution or providers. Interpretation This study highlights a relatively high rate of severe critical events during the anaesthesia management of children for surgical or diagnostic procedures in Europe, and a large variability in the practice of paediatric anaesthesia. These findings are substantial enough to warrant attention from national, regional, and specialist societies to target education of anaesthesiologists and their teams and implement strategies for quality improvement in paediatric anaesthesia. Funding European Society of Anaesthesiology