Metaldehyde

Amyloid-Like Protein Aggregation Toward Pesticide Reduction

Pesticide overuse is a major global problem and the cause of this problem is noticeable pesticide loss from undesired bouncing of sprayed pesticide droplets and rain erosion. This further becomes a primary source of soil and groundwater pollution. Herein, the authors report a method that can enhance pesticide droplet deposition and adhesion on superhydrophobic plant leave surfaces by amyloid-like aggregation of bovine serum albumin (BSA). Through the reduction of the disulfide bond of BSA by tris(2-carboxyethyl) phosphine hydrochloride (TCEP), the amyloid-like phase transition of BSA is triggered that rapidly affords abundant phase-transitioned BSA (PTB) oligomers to facilitate the invasion of the PTB droplet into the nanostructures on a leaf surface. Such easy penetration is further followed by a robust amyloid-mediated interfacial adhesion of PTB on leaf surface. As a result, after mixing with pesticides, the PTB system exhibits a remarkable pesticide adhesion capacity that is more than 10 times higher than conventional fixation of commercial pesticides. The practical farmland experiments show that the use of PTB aggregation could reduce the use of pesticides by 70-90% while ensuring yield. This work demonstrates that current pesticide dosage in actual agriculture production may be largely reduced by utilizing eco-friendly amyloid-like protein aggregation.

Retrospective evaluation of the use of hemodialysis in dogs with suspected metaldehyde poisoning (2012-2017): 11 cases

OBJECTIVE

To evaluate dogs treated with hemodialysis for severe metaldehyde intoxication and to compare them with conventionally-managed patients.

DESIGN

Retrospective study (2012-2017).

SETTING

University teaching hospital.

ANIMALS

Data from 18 dogs with severe metaldehyde intoxication were analyzed. Eleven dogs were treated with intermittent hemodialysis and 7 managed conventionally.

INTERVENTIONS

None.

MEASUREMENT AND MAIN RESULTS

Metaldehyde poisoning was diagnosed based on clinical signs and toxicological analysis or presence of turquoise material in the gastrointestinal content. Clinical signs, additional treatments, dialysis prescription, duration of anesthesia and hospitalization, complications, and outcome were documented. Results were analyzed by t-test, Mann-Whitney U-test, and Chi-square test. P < 0.05 was considered significant. Dialysis was performed for median (range) 180 min (150-420 min) with median of 2.28 L/kg (1.66-4.48 L/kg) blood volume processed. In the hemodialysis group, anesthesia was discontinued at a median of 3.0 hours (1.5-6.7 h) after starting dialysis. The conventional-group received general anesthesia for a median of 17.5 hours (7.0-30.5 h). No further anticonvulsive treatment was necessary for the hemodialysis group. Time to hospital discharge was shorter in dialyzed dogs (median 18 h; 15-41 h) compared to conventionally treated dogs (median 89 h; 61-168 h; P = 0.0014). Aspiration pneumonia was reported in 5 conventionally treated dogs and none of the dialyzed dogs (P = 0.001). Five dialyzed dogs developed hematoma at the dialysis catheter site. One dog in each group was euthanized.

CONCLUSION

Hemodialysis significantly decreases the requirement for anesthesia and length of hospitalization in dogs with metaldehyde intoxication. Aspiration pneumonia occurred less often in dialyzed patients. Prospective studies are warranted to confirm the clinical utility of hemodialysis in dogs with metaldehyde poisoning.

Pesticide toxicosis in the horse

Toxicosis from pesticides rarely occurs in horses and is usually the result of inappropriate pesticide use or handling by humans. Organophosphorus and carbamate insecticides inhibit acetylcholinesterase and are the insecticide class most frequently associated with toxicosis in domestic animals. Metaldehyde is a molluscicide, and zinc phosphide is a rodenticide, both of which have caused toxicosis in horses. All three of these pesticides affect the nervous system of horses and can be fatal if not treated promptly.