TISSUE CULTURE REAGENTS 303 



Solutions containing calcium in levels comparable with TG Balanced Salt Solu- 

 tion (Earle's BSS) give a faster clotting rate and a firmer coagulum w^ith TG 

 Ghicken Plasma than do extracts prepared with a lower calcium content. 



TG CHICK EMBRYO (B470) 



TC Chick Embryo is sterile whole minced Chick Embryo dried from the 

 frozen state and certified for use in tissue culture procedures requiring chick 

 embryo extract. It is prepared from selected eleven-day old chick embryos and 

 is packaged in 2 ml. quantities. 



TC Chick Embryo is prepared for use by adding 2 ml. TC Reconstituting 

 Fluid or TC Triple Distilled Water to each vial to wet the desiccated embryo 

 tissue thoroughly. Four volumes (8 ml.) TC Balanced Salt Solution are then 

 added to each bottle. The solids are suspended by rotating the bottles gently in 

 an end-over-end motion. Do not shake. The suspension is warmed to 35-3 7 °C. 

 for 30-60 minutes with occasional rotation to resuspend the solids. The bottles 

 are then centrifuged at 2500-3000 rpm for 5 minutes to sediment the particulate 

 matter following which, the supernatant is drawn off aseptically and trans- 

 ferred to a clean sterile container. The resultant extract is a 20 per cent Chick 

 Embryo Extract, EEgo, and is ready for use. Unused portions of the extract should 

 be stored at 2-6° C. Storage of the extract for periods longer than one week are 

 not recommended. 



It has been our observation that Embryo Extracts diluted with Balanced Salt 

 Solutions containing calcium in levels comparable with TG Balanced Salt Solu- 

 tion (Earle's BSS) give a faster clotting rate and a firmer coagulum with TG 

 Ghicken Plasma than do extracts prepared with a lower calcium content. 



TG BEEF EMBRYO EXTRACT EEioo (B396) 

 TC Beef Embryo Extract EE^qq is sterile desiccated undiluted Beef Embryo 

 Extract certified for use in tissue culture procedures requiring mammalian 

 embryo extract. It is prepared from fresh bovine embryos 60-90 days of age 

 and is packaged in 2 ml. quantities. 



TC Beef Embryo Extract EEj^qq is reconstituted to its original volume by 

 adding, aseptically, 2.0 ml. TC Reconstituting Fluid or TC Triple Distilled 

 Water to each bottle. When the contents of the botde has uniformly combined 

 with the liquid it is then diluted further as desired with TC Balanced Salt 

 Solution. A 20 per cent Embryo Extract, EE20, has been found useful in tissue 

 culture procedures. This concentration is obtained by adding four volumes 

 (8 ml.) of TC Balanced Salt Solution to the reconstituted Embryo Extract EEiqo- 

 The Reconstituting Fluid and Balanced Salt Solution may be added conveniently 

 by means of a sterile syringe and needle. 



The diluted Embryo Extract EE20, or other desired concentration, is allowed 

 to stand at 35-3 7 °C. for 30-60 minutes to obtain maximum solution of the 

 nutrients. Solution of the desiccated material is accelerated by gentle end-over- 

 end rotation of the bottle. Do not shake. A small portion of the desiccated 

 Embryo Extract may remain in suspension. This insoluble residue should be 

 removed by centrifugation of the bottle for 10 minutes at 2500-3000 rpm. The 

 supernatant liquid is now ready for use. Unused portions of the diluted Embryo 

 Extract should be stored in tightly stoppered containers in the refrigerator at 

 2-6°C. Storage of the reconstituted TC Beef Embryo Extract for periods longer 

 than one week, even though refrigerated, is not recommended. 



