MODIFIED METHOD OF PREPARING CONCENTRATED SMEARS OF BONE MARROW

[摘要] THE FOLLOWING brief communication concerns a method of obtaining bone marrow smears which are practically devoid of dilution with cells from the peripheral blood. In the authors' experience bone marrow particles are not usually obtained from small infants and children. Therefore it has not been possible to make use of the standard technique of aspiration of the bone marrow into a heparinized syringe, placing the aspirate on a watchglass, and then selecting a particle of bone marrow for smear or imprint. Neither has the alternative method of centrifuging heparinized marrow in Wintrobe hematocrit tubes proved satisfactory, because the small quantity of marrow generally taken from infants is insufficient to fill a Wintrobe tube. Another difficulty is in separating the buffy coat from the erythrocyte layer in the Wintrobe tube. [SEE FIG. 1 IN SOURCE PDF]METHODThe present method consists of expelling two or three small drops of bone marrow from the aspirating syringe on to a glass slide; this is transferred by means of capillary attraction into a micro-hematocrit tube. The micro-hematocrit tube is heat-sealed as in the determination of the micro-hematocrit of peripheral blood. The tube is centrifuged for 5 minutes at high speed, and then broken at the interface of the erythrocytes and buffy coat. This is accomplished by the use of an ordinary metal file such as is used for cutting glass vials. The buffy coat with the supernatant plasma is expelled on to a coverslip, smeared and stained in the usual manner (Fig.1).This method has proved useful in providing a concentrated preparation of marrow cells and in yielding a more informative picture of the activity of the bone marrow than has been available with the use of ordinary smears.

[学科分类] 儿科学