Additive reagents have been investigated to improve the stability of methanolic Wright's stain. The addition of ammonium halides, monoalkylamine hydrochlorides, dialkylamine hydrochlorides or trialkylamine hydrochlorides to methanolic Wright's stain was found to enhance the stability of stain components in methanol. No change in performance is observed with these additives present. Random precipitation in the stain solution was still observed with the addition of ammonium halides and monoalkylamine hydrochlorides. No precipitation was found in stain solutions containing hydrochlorides of most dialkylamines and trialkylamines. Of the compounds evaluated, 0.6% diethylamine hydrochloride added to methanolic stain solutions produced the most desirable overall results. Mechanisms of stabilization and precipitation in these stain solutions are proposed. Essentially, separation of the thiazine-eosinate ion pair through interaction with an appropriate additive increases stain stability. The solubilities of thiazine-eosinate or additive cation-eosinate ion pairs in methanol determine the formation of precipitate in such stain solutions.

Degradation of methanolic Wright's stain solutions was greatly diminished with the addition of diethylamine hydrochloride and dimethylamine hydrochloride as costabilizers. Precipitation problems were eliminated by the dual additives. The stabilized stain solutions demonstrated good staining performance on blood smears. Methods for predicting the shelf life using calculated analytical parameters are described. Using these methods, the shelf life of a control stain solution was predicted to be 0.7 years; predicted shelf life was more than tripled with the addition of diethylamine hydrochloride and was increased approximately 27 times with the addition of both diethylamine hydrochloride and dimethylamine hydrochloride.

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Abstract:A quantitative method for the determination of potato lectin activity has been developed. In the method, lectin is incubated with an excess of red blood cells (RBC) in phosphate buffered saline at 25 "C. Maximum agglutination is reached within 60 min. Agglutinated RBC are then separated from nonagglutinated RBC by filtration. The agglutinated RBC remaining on the filter paper are then lysed and eluted using a solution of Triton X-100. The hemoglobin content of the lysed RBC is measured at 415 nm. The number of agglutinated RBC is calculated from the hemoglobin value. One unit of lectin activity will agglutinate one million RBC.