Simultaneous determination of two acute poisoning rodenticides tetramine and fluoroacetamide with a coupled column in poisoning cases

Hapten Design and Monoclonal Antibody to Fluoroacetamide, a Small and Highly Toxic Chemical

Fluoroacetamide (FAM) is a small (77 Da) and highly toxic chemical, formerly used as a rodenticide and potentially as a poison by terrorists. Poisoning with FAM has occurred in humans, but few reliably rapid detection methods and antidotes have been reported. Therefore, producing a specific antibody to FAM is not only critical for the development of a fast diagnostic but also a potential treatment. However, achieving this goal is a great challenge, mainly due to the very low molecular weight of FAM. Here, we design two groups of FAM haptens for the first time, maximally exposing the fluorine or amino groups, with the aid of linear aliphatic or phenyl-contained spacer arms. Interestingly, whereas the hapten with fluorine at the far end of the hapten did not induce an antibody response to FAM, the hapten with an amino group at the far end and phenyl-contained spacer arm triggered a significantly specific antibody response. Finally, a monoclonal antibody (mAb) named 5D11 was successfully obtained with an IC₅₀ value of 97 μg mL⁻¹ and negligible cross-reactivities to the other nine functional and structural analogs.

Treatment of severe fluoroacetamide poisoning in patient with combined multiple organ dysfunction syndrome by evidence-based integrated Chinese and Western medicines: A case report

RATIONALE

Fluoroacetamide poisoning is the acute and severe disease of human, which leads to nervous, digestive, and cardiovascular system damage or even death in a short period of time.

PATIENT CONCERNS

We report a case of a 65-year-old woman with loss of consciousness, nausea, and vomiting who was sent to the hospital by passers-by.

DIAGNOSIS

She was diagnosed with severe fluoroacetamide poisoning with combined multiple organ dysfunction syndrome.

INTERVENTIONS

When the diagnosis was unclear, we gave gastric lavage, support and symptomatic treatment, and closely with the vital sign. When the diagnosis was clear, based on the evidence of retrieved, muscle injection of acetamide, calcium gluconate, and vitamin C. Traditional Chinese medicine aspect, oral administration of mung bean soup of glycyrrhizae and Da-Cheng-Qi decoction enema.

OUTCOMES

By setting reasonable treatment for patients, she had no special discomfort and complications after treatment. Besides, through 1-month follow-up, it was confirmed that the treatments were effective.

LESSONS

Evidence-based integrated Chinese and Western medicines can effectively improve the therapeutic effects in severe fluoroacetamide-poisoned patients with combined MODS.

Sensitive Immunoassay for Detection and Quantification of the Neurotoxin, Tetramethylenedisulfotetramine

Tetramethylenedisulfotetramine (TETS, tetramine) is a formerly used and highly neurotoxic rodenticide. Its lethality, recent history of intentional use for mass poisoning, and the absence of a known antidote raise public health concerns. Therefore, rapid, high throughput, and sensitive methods for detection and quantification of TETS are critical. Instrumental analysis method such as GC/MS is sensitive but not rapid or high throughput. Therefore, an immunoassay selective to TETS was developed. The assay shows an IC50 of 4.5 ± 1.2 ng/mL, with a limit of detection of 0.2 ng/mL, comparable to GC/MS. Performance of the immunoassay was demonstrated by a recovery study using known concentrations of TETS spiked into buffer and human and mouse serum matrices giving recoveries in the range of 80-120%. The assay demonstrated good correlation in TETS recovery with established GC/MS analysis. The immunoassay was then used to quantify TETS concentration in the serum of mice exposed to 2× LD50 dose of TETS and to monitor kinetics of TETS clearance from blood over a short period of time. TETS concentration in the serum reached 150 ng/mL without significant change over 4 h post-treatment. Results obtained with the immunoassay had good correlation with GC/MS analysis. Overall, this immunoassay is an important tool to rapidly detect and quantify levels of TETS from biological samples with high sensitivity. The assay can be adapted to multiple formats including field or hospital use.

Lessons learned from poisoning cases caused by 2 illegal rodenticides: Tetramine and fluoroacetamide

BACKGROUND

Tetramine (tetramethylene disulphotetramine, TETS) and fluoroacetamide (FAA) are known as illegal rodenticides with high toxicity to animal species and human beings, which could lead to severe clinical features, including reduction of consciousness, convulsions, coma, and even death.

METHODS AND RESULTS

We presented 2 cases that involved rodenticides poisoning. Even though the patients showed severe manifestations, they were initially misdiagnosed, resulting in 2 persons finally died from TETS and FAA poisoning in homicide cases.

CONCLUSION

From the clinical and forensic experience of these 2 cases, we suggest that physicians should consider TETS and FAA poisoning when patients present generalized seizures, especially in some cases without clear cause and diagnosis of disease. Early diagnosis and treatment are essential for positive management and criminal investigation in intentional poisoning cases. Moreover, clinical toxicology education should be reinforced.

Determination of Rodenticide Tetramethylenedisulfotetramine (Tetramine) in Processed Foods by Gas Chromatography-Tandem Mass Spectrometry

A GC-MS/MS method for determination of the rodenticide tetramethylenedisulfotetramine was developed. Tetramethylenedisulfotetramine was extracted from the sample with ethyl acetate in the presence of anhydrous sodium sulfate. Then, an aliquot of the extract was evaporated under vacuum, followed by acetonitrile/hexane partitioning, and cleanup with a tandem graphitized carbon/primary secondary amine (PSA) column, prior to GC-MS/MS analysis. The recoveries from 10 processed foods, all of which were fortified at 0.1 mg/kg, were in the range of 85-96%, and the relative standard deviations were less than 7%. The proposed method effectively removed co-extracted matrix components, and matrix effects were negligible in the GC-MS/MS analysis. In addition, no interfering peaks were found in the chromatograms of the blank samples at the retention time of tetramethylenedisulfotetramine, indicating that the method is highly selective. Overall results suggest that the proposed method is suitable for determining tetramethylenedisulfotetramine contained in processed foods.

In vitro selection of DNA aptamers binding pesticide fluoroacetamide

Fluoroacetamide (Mw = 77.06) is a lethal rodenticide to humans and animals which is still frequently abused in food storage somewhere in China. The production of antibodies for fluoroacetamide is difficult due to its high toxicity to animals, which limits the application of immunoassay method in poison detection. In this work, aptamers targeting N-fluoroacetyl glycine as an analog of fluoroacetamide were selected by a specific systematic evolution of ligands by exponential enrichment (SELEX) strategy. The binding ability of the selected aptamers to fluoroacetamide was identified using surface plasmon resonance (SPR)-based assay. The estimated KD values in the low micromolar range showed a good affinity of these aptamers to the target. Our work verified that the SELEX strategy has the potential for developing aptamers targeted to small molecular toxicants and aptamers can be employed as new recognition elements instead of antibodies for poison detection.

Hair as a specimen to document tetramethylene disulfotetramine exposure

Tetramethylene disulfotetramine (tetramine) is a rodenticide that has been banned for many years in China. Since 2005, inhabitants of a village in the Henan Province have been suffering from grand mal seizures. To investigate the possibility of tetramine as the cause, we developed a method to determine tetramine in human hair. Sample preparation involved external decontamination, frozen pulverization, and ultrasonication in 2 mL ethyl acetate in the presence of cocaine-d3 as an internal standard. The method exhibited good linearity; calibration curve was linear over a range of 0.1-20 ng/mg hair. The limit of detection for the assay was 0.05 ng/mg hair. Except for one subject (No. 4), all head and pubic hair samples were positive for tetramine. The concentrations of tetramine in pubic hair were significantly higher than those in the same subjects' head hair samples. Because of a long retention in body, segmental head hair analysis cannot provide an accurate exposure history of tetramine in the body.