Results Of Toxicity Studies Research Articles

A Wide Range Experimental Herbicide

Abstract Abstract An experimental herbicide, AC 92,553 has been developed by Cyanamid International to control most annual grasses and several small-seeded broad-leaved weeds, applied either pre- or post-seeding on a wide range of crops. The influence of soil and weather conditions on the effectiveness of the herbicide are discussed. Suggested combinations with other herbicides and rates of application are given. The results of toxicity studies are summarised.

STEREOSPECIFICITY IN THE ENZYMATIC HYDROLYSIS OF TABUN AND ACETYL-β-METHYLCHOLINE CHLORIDE

The hydrolysis of the powerful cholinesterase inhibitor, tabun, at pH 7 to 7.5 by a rat serum enzyme in bicarbonate buffer involves two simultaneous first-order reactions. A fast, enzyme-catalyzed reaction destroys the toxic dextrorotatory isomer of tabun. The much slower hydrolysis of the levorotatory and apparently non-toxic isomer is probably a non-enzymatic reaction. The enzymatic hydrolysis of acetyl-dl-β-methylcholine chloride by a rat brain homogenate has been studied as a model reaction. Only one-half of the racemic compound is hydrolyzed in contrast to the complete hydrolysis of acetylcholine chloride by the same enzyme source. These results and the results of toxicity studies on the hydrolyzing solution indicate that true cholinesterase hydrolyzes only the dextrorotatory isomer of acetyl-dl-β-methylcholine chloride.

STEREOSPECIFICITY IN THE ENZYMATIC HYDROLYSIS OF TABUN AND ACETYL-β-METHYLCHOLINE CHLORIDE

The hydrolysis of the powerful cholinesterase inhibitor, tabun, at pH 7 to 7.5 by a rat serum enzyme in bicarbonate buffer involves two simultaneous first-order reactions. A fast, enzyme-catalyzed reaction destroys the toxic dextrorotatory isomer of tabun. The much slower hydrolysis of the levorotatory and apparently non-toxic isomer is probably a non-enzymatic reaction. The enzymatic hydrolysis of acetyl-dl-β-methylcholine chloride by a rat brain homogenate has been studied as a model reaction. Only one-half of the racemic compound is hydrolyzed in contrast to the complete hydrolysis of acetylcholine chloride by the same enzyme source. These results and the results of toxicity studies on the hydrolyzing solution indicate that true cholinesterase hydrolyzes only the dextrorotatory isomer of acetyl-dl-β-methylcholine chloride.

A contribution to the pharmacology of 5-nitroguaiacol*,

In vitro tests on mercurated 5-nitroguaiacol indicate that it may be an effective antiseptic, both in its solid form and in solution as the sodium salt. The results of toxicity studies are reported.

Mortality of Rhagoletis Completa Cress. (Diptera: Trypetidae) Through Ingestion of Certain Solid Materials

Ingestion studies in which lead arsenate, barium fluosilicate, cryolite, copper carbonate, hydrated lime, talc, diatomaceaus earth, bentonite, sulfur, and ground tobacco leaves were employed, demonstrated that adult flies (Rhagoletis completa Cress.) actually take undissolved particles into the stomach. Results of toxicity studies in which the above materials were employed are graphically presented.