304 DIFCO MANUAL 



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 (B471) 



TC Beef Embryo is sterile whole minced Beef Embryo dried from the frozen 

 state and certified for use in tissue culture procedures requiring beef embryo 

 extract. It is prepared from beef embryos 60-90 days of age and is packaged in 

 2 ml. quantities. 



TC Beef 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 35-37'^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 liquid is drawn off aseptically and trans- 

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

 Embryo Extract, EE20, 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 v>^ith 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 

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



TG GORD SERUM, HUMAN (B356) 



TC Cord Serum, Human is sterile desiccated whole human cord serum 

 certified for use in culturing tissue cells in vitro. It is obtained from blood from 

 the placenta at childbirth. Each preparation is from the pooled sera from 25 

 or more placentae. It is packaged in 5 ml. quantities. 



TC Cord Serum, Human is reconstituted to its original volume by adding, 

 aseptically, 4.5 ml. TC Reconstituting Fluid or TC Triple Distilled Water to 

 each bottle. Solution of the material is accelerated by gentle end-over-end rota- 

 tion of the bottle. Do not shake. When solution is complete, it is ready for use. 

 Unused portions of the reconstituted TC Cord Serum, Human should be kept in 

 tightly stoppered containers in the refrigerator at 2-6° C. Storage of the recon- 

 stituted TC Cord Serum, Human for periods longer than one week, even though 

 refrigerated, is not recommended. 



The Reconstituted TC Cord Serum, Human is alkaline in reaction due to 

 loss of carbon dioxide in the desiccation process and if desired may be adjusted 

 to pH 7.2-7.4 in an atmosphere of carbon dioxide as described for the adjust- 

 ment of Chicken Plasma page 301. 



TG HORSE SERUM (B357) 



TC Horse Serum is sterile desiccated whole, pooled horse serum certified for 

 use in culturing tissue cells in vitro. It is obtained from blood from fasted, 

 healthy, lean geldings, and is packaged in 5 ml. quantities. 



