TRANSPARENT CHAMBER 

 TECHNIQUES 



355 



TRANSPARENT CHAMBER 

 TECHNIQUES 



greatly improved (Clark, E. R., et. al., 

 Anat. Rec, 1930, 47, 187-211). 



The cartilage of the rabbit ear serves 

 as a natural support for chambers 

 which were constructed first of cellu- 

 loid and mica and later on of glass and 

 mica, or methyl methacrylate resin (lu- 

 cite, perspex). An area of skin the size 

 of the chamber is dissected away from 

 the cartilage on both sides of the ear, 

 leaving the central artery intact. The 

 chamber units are inserted close to the 

 main artery, usually with the observa- 

 tion area at the inner surface of the 

 ear, and the skin is drawn over the 

 chamber edges and trimmed to expose 

 the observation area. The chamber is 

 held in position by the use of bolts or 

 pegs and by fitting the cartilage into 

 a space between the upper and lower 

 pieces. Protective covers of celluloid 

 or vinylite are used to prevent injury. 



Various types of chambers have been 

 designed for special purposes. The 

 preformed-tissue design used in studies 

 of the original tissues of the ear is 

 restricted to low magnification observa- 

 tions of blood vessels within a rela- 

 tively thick layer of skin. Introduc- 

 tion of the preformed-tissue chamber 

 into the rabbit ear arouses cellular and 

 circulatory disturbances which require 

 10-14 days to subside before satisfac- 

 tory studies can be made. 



Greatly improved resolution of cells 

 and tissues at high magnifications was 

 achieved by the round-table designs 

 (Clark, E. R., et al., cited above), in 

 which a central hole is punched through 

 the cartilage and a narrow space of 

 from 40-75 micra thickness is provided 

 for the ingrowth of newly formed blood 

 vessels and connective tissue from the 

 edges of the cartilage. The thickness 

 of the space is controlled by spacers 

 placed between the central round table 

 and the coverslip. Clark, E. R. and 

 Clark, E. L., have applied these tech- 

 niques to detailed descriptive accounts 

 of the growth, differentiation, and be- 

 havior of blood vessels, growth of 

 lymphatics and nerves, development of 

 fat tissues, migration of leukocytes and 

 macrophages, and inflammatory reac- 

 tions. 



Abell and Clark, in devising the moat 

 chamber (Anat. Rec, 1932,53, 121-140) 

 modified the round-table design to 

 include a well, provided with silver 

 cannulae, for the introduction of chem- 

 ical solutions into the chamber in con- 

 tact with the living tissue. This design 

 was used in studies of diffusion of dyes 

 and of effects of chemical agents on 

 tissues. The round-table designs re- 

 quired 3 to 4 weeks for complete vas- 



cularization of a table area having a 

 diameter of approximately 7 mm. 



In the removable top chamber, Will- 

 iams improved the method for the in- 

 troduction of cell transplants. These 

 are implanted several weeks after 

 insertion of the chamber, when vascu- 

 larization of the round table is com- 

 plete. Recently Williams has suc- 

 ceeded in prolonging the duration of 

 the transplant chamber through the 

 use of tantalum gauze (Williams, R. 

 G., Anat. Rec, 1948, 101, 291-298). 

 Growth of blood vessels and connective 

 tissue through the meshes serves to 

 reinforce the attachments between 

 tissue and chamber. The useful dura- 

 tion of some of the tantalum chambers 

 has been approximately 3 years (per- 

 sonal communication). 



Ebert, Florey, and Pullinger (Ebert, 

 R. H., Florey, H. W. and Pullinger, 

 B. D., J. Path, and Bact., 1939, 48, 

 79-94), introduced the use of methyl 

 methacrylate resin (Incite, perspex) in 

 the construction of the chamber and 

 modified an earlier design of the trans- 

 plant chamber by Clark (cited above), 

 to give access through a removable 

 plug introduced into the central table. 

 This design has been used in studies of 

 tissue reactions in tuberculous infec- 

 tion (Ebert, R. H., Ahern, J. J. and 

 Bloch, R. G. (Proc Soc Exp. Biol. 

 Med., 1948, 68, 625-^33). Further mod- 

 ifications of this design were published 

 recently which simplify the procedures 

 (Ahern, J. J., Barclay, W. R. and Ebert, 

 R. H., Science, 1949, 110, 665). 



Essex has made use of a Incite cham- 

 ber in studies of peripheral nerve in- 

 jury and repair (Essex, H. E. and de 

 Rezende, N., Am. J. Physiol., 1943, 

 140, 107-114), and in studies of leuko- 

 cytes in leukopenia (Essex, H. E. and 

 Grana, A., Am. J. Physiol., 1949, 159, 

 396-400). Construction details of this 

 chamber have been given (Essex, H, 

 E. in Methods in Medical Research, 

 Year Book Publishers, 1948 1, 139-145). 



Chambers have been described for 

 other sites, organs, and species. Per- 

 manent cranial windows have been de- 

 signed, (Wentsler, N. E., Anat. Rec, 

 1936, 66, 423^435), in which a small glass 

 window set into a celluloid frame is se- 

 cured to the skull with small silver pegs. 

 A disadvantage of this type of window, 

 as of the Incite disks made by Sohler, 

 Lothrop, and Forbes (J. Pharmacol., 

 1941, 71, 325-330), is its small size, 

 having a diameter of 12-16 ram. 



Sheldon et al. (Sheldon, C. H. 

 Pudenz, R. H., Restarski, J. S. and 

 Craig, W. McK., J. Neuro-phj-siol., 

 1944, 1, 67-75) describe a technique for 



