ANTERIOR CHAMBER 

 TRANSPLANTATION 



the size of the animal used. Animals 

 larger than mice are immobilized on an 

 operating board with tie strings in such 

 a manner that the desired eye presents 

 to the operator. The cornea is anaes- 

 thetized by contact with a 5% aqueous 

 solution of cocaine administered with 

 a medicine dropper. An incision is 

 made at approximately the midpoint of 

 the upper border of the limbus utilizing 

 a sharp double-edged corneal knife. 

 The knife is directed slightly forward 

 so that the blade enters the anterior 

 chamber without damage to the iris. 

 The pressure necessary to pierce the 

 cornea is sufficient, even with a sharp 

 knife, to rotate the eyeball beneath the 

 lower lid and conceal the operative 

 field. A short, quick thrust of the 

 knife, however, results in an adequate 

 opening and the temporary obscurity 

 is inconsequential. Withdrawal of the 

 blade is accompanied by the escape of 

 a small amount of aqueous humor, but 

 unless the iris has been cut by a mis- 

 directed knife, there is no bleeding. 



Transfer of the tissue is effected by 

 means of a trocar commensurate in 

 diameter with the corneal incision. 

 The trocar should be equipped with a 

 tight-fitting plunger and a short bev- 

 elled mouth with all edges filed to 

 smoothness. A small fragment of tissue 

 is placed in the mouth of the trocar 

 and forced into the barrel, a step greatly 

 facilitated by withdrawing the plunger 

 to produce suction. The tip of the 

 trocar is inserted through the incision 

 a short distance so that the bore is 

 entirely within the chamber and the 

 fragment is expelled. It is important 

 that all manual pressure about the eye 

 and head of the animal be released 

 before withdrawing the trocar to pre- 

 vent escape of the fragment. Finally, 

 the fragment is forced into the inferior 

 angle of the iris by applying light pres- 

 sure along the corneal surface with a 

 blunt instrument. The incision is not 

 closed. 



The knife should be sharp and of such 

 width that a stab wound will admit the 

 trocar. The use of a narrow knife 

 necessitates side cutting to obtain a 

 sufl&cient opening and this may be 

 attended by iris damage with conse- 

 quent bleeding. Pointed surgical 

 blades or single-edged corneal knives 

 are undesirable, for the triangular cut 

 produced heals slowly and may result 

 in herniation of the iris. 



The fragments of tissue to be trans- 

 planted should be cut with sharp instru- 

 ments and should not exceed 1 mm. in 

 diameter. The careful selection of 

 fragments is of the utmost importance 



14 ANTERIOR CHAMBER 



TRANSPLANTATION 



in the heterologous transplantation of 

 human cancer. In addition to essential 

 parenchyma, all human cancers contain 

 stroma and many are infiltrated with 

 desmoplastic connective tissue. Such 

 tissues are adult in nature and will not 

 grow on heterologous transfer. In fact, 

 their presence in quantity will give rise 

 to a foreigh body reaction in the alien 

 host and result in death of the trans- 

 plant. It is essential, therefore, that 

 selection be based on the content of 

 tumor parenchyma and some knowledge 

 of gross pathology is necessary for such 

 a differentiation. Frozen sections ob- 

 tained from different areas of the tumor 

 mass are of considerable aid in some 

 cases. It is obvious that necrotic 

 tumor or normal tissue adjacent to the 

 tumor are not suitable materials for 

 transfer. 



The placing of the fragment in a 

 wedged position in the inferior angle of 

 the iris is important for early vasculari- 

 zation. Occasionally, fragments so 

 placed work loose shortly after opera- 

 tion and an examination with the re- 

 quired readjustment is desirable before 

 returning the animals to the colony. 

 Fixation occurs within a few hours and 

 further check is unnecessary. 



A slight modification of the technique 

 is desirable when applied to mice or to 

 newborn animals of larger species. 

 General anesthesia is preferable and 

 may be effected with ether or nembutal. 

 Both hands are employed in the opera- 

 tion and preliminary loading of the 

 trocar is necessary. The trocar is made 

 by shortening the bevel at the tip of 

 a 20-gauge hypodermic needle. A suit- 

 able, tight-fitting plunger can be manu- 

 factured or obtained simply be select- 

 ing a wire stylet of proper size from the 

 stock supplied with the needles and ap- 

 plying a knob of plastic material to one 

 end. 



The mouse is held loosely in the left 

 hand and the lids of the right eye forced 

 apart with the thumb and index finger. 

 Slight pressure with the fingers causes 

 the eye to protrude sufficiently to allow 

 adequate exposure for the operation. 

 An incision is made at the upper border 

 of the limbus using a double-edged knife 

 of the same caliber employed in larger 

 animals. 



The trocar, held between the thumb 

 and middle finger of the right hand, is 

 inserted into the chamber through the 

 incision and the fragment expressed 

 by pushing the plunger with the index 

 finger. In order to prevent extrusion 

 and escape of the fragment through the 

 incision, all pressure exerted on the 

 animal by the left hand should be re- 



