-71- 

 thoroughly cleaned before inserting the grids. The 

 polyethylene tube is then placed into a glass tube (3.5 mm 

 interior diameter). 



To retain their proper orientation, the grids are 

 carefully inserted, one at a time, into the polyethylene tube 

 as it is being placed into the glass tube. When in place, and 

 prior to staining, grids are moistened by rinsing them 5-10 

 seconds in deionized water. Rinsing can be accomplished by 

 using an intravenous set (e.g., IV Set, McGaw Laboratories, 

 Inc., Sabana Grande, Puerto Rico 00747) to supply a jet of 

 water sufficiently fine to enter the glass and polyethylene 

 tubes (Fig. 58). After rinsing, excess water can be eliminated 

 from the tubes by gently tapping the tubes on a solid surface 

 covered with filter paper or shaking them by hand. For 

 staining, the tubes are attached to a 2 ml pipette pump (pi. 

 pump 2000, Glasfirn Giessen, D 6300 Giessen, West Germany) 

 (Fig. 59). As fluids are drawn up into the glass tube, care 

 should be taken to avoid air bubbles possibly present on the 

 grids . 



These staining and rinsing devices have been used 

 successfully for over one year. The tubes can be reused, but 

 must be cleaned thoroughly between operations. Labs using this 

 technique are able to handle many grids simultaneously. In 

 our experience, the grid holder provides a simple, efficient 

 way for staining thin sections and has reduced mechanical 

 damage and contamination of thin sections. 



