Manoilov Reaction

MANOILOV REACTION was proposed in 1923 by Dr. Manoilov for determining the sex of humans and animals from their blood. Soon the scope of its application was extended by the author also to the plant world, where he managed, as in humans and other animals, to identify two main types of reactions—the "male" and the "female." Finally, individual modifications of the main Manoilov reaction were proposed by the author also for determining human race, and for determining the sex of a fetus from the mother's blood. The Manoilov reaction was discovered empirically, and it has still not been definitively established what causes its particular type. Apparently, there is no dependence on a specific sex hormone, but the reaction is caused by a different concentration in the blood, respectively in tissue extracts of male and female individuals and in mineral extracts of unknown substances, in particular substances possessing reducing properties. The technique of the main Manoilov reaction recommended by the author for determining sex in humans is as follows: an unheated erythrocyte emulsion is taken (obtained by shaking a blood clot in a physiological NaCl solution; Bar-por recommends taking an emulsion corresponding in color to a 2–2¹/₂% Hb content), and to 3 cm³ of it are added 10 drops of a 1% aqueous filtered solution of Merck's papayotin (reagent I); then 3 drops of a 1% alcoholic solution of Grübler's Dahlia dye or a 1% aqueous filtered solution of methyl violet or crystal violet (reagent II); 10 drops of a 1% aqueous solution of KMnO₄ (reagent III); 3 drops of 40% HCl (reagent IV) and 5 drops of a 2% aqueous filtered solution of thiosinamine (reagent V). After the addition of each reagent, the mixture is shaken, and it must be mixed especially well after the addition of the dye. In the case of a "male" reaction, the liquid becomes decolorized; in the "female" one, it remains more or less intensively colored. Since sometimes better results are obtained not with papayotin, but with pepsin or trypsin, the author of the reaction recommends conducting the experiment in 3 test tubes simultaneously with each of these enzymes, considering a uniform result in 2 test tubes to be the final answer. In doubtful and indistinct answers, the author introduces a "correction" into the reaction, leaving sera with a weak "female" reaction to stand for several days, after which they become decolorized if they belong to males; decolorization can be enhanced by adding 10 drops of reagent III, 2 drops of IV, and 5 drops of V; in female sera that have given decolorization, the color is restored after adding 5–8 drops of KMnO₄, which is not observed with male serum. It is necessary to work with pipettes accurately graduated into drops (counting a drop = ¹/₂₀ cm³) and with previously verified reagents. Correct answers in determining sex in human blood using the Manoilov reaction were obtained by a number of authors in 86–97.4% of cases, in determining race in 81–91.7%, in determining fetal sex in 72–89%. At present, the Manoilov reaction is in the stage of verification and study of its chemical side. Its practical application in medicine at the present moment is premature in view of the unclear nature of all those diverse and complex relationships and factors that can influence its result.