Universlty of Manitoba, ln Partîal Fulfiìlment - MSpace at the ...

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5.3.3 .o¡literation,lof
lt¡tro¿u¿¿¿
eir space
There fs llttle evidence that vibration of the eggs or materials
ln the p!astîcine/parafilm covers are responslble for the malformations
produced by wÌndowÌng. Thîs suggesb that the presence of an introduced
alr space above the developing embryos may be the causa¡ agent. To
test this posslbilîty the lntroduced alr space was oblíterated in three
dlfferent ways at varying ìntèrva¡s after windowing at 26 hours of
lncubatlon. ln each experlment eggs were sealed wîth parafilm and relncubated
to 72 hours wlthout turnlng but w¡th the sealed lirindow facing
downwards (figs. 8n and B and 9A and B),
' ln the first experiment the lntroduced aîr space was filled with
albumen from unwindowed eggs of the same batch, at 26,32,38, 44 and 50
hours of încubation (or 0, 6, 12, l8 and 24 hours after wîndowing).
Tables 14 and 15 and Fig.12, show that mortal ity and the overall malformation
rates decl ined with earlier obl iteratíon of the air space.
ln the second experiment F 12 culture medium (ttam, I965).
was used to obl îterate the introduced air space êt the same intervals
after windowing. Tables l6 and 17 and Fi9. l3 also reveal a
reduction in.mortality and overal I malformation rates with earlier
obliterat¡on.
Finally, reexpansion of the air cell with a rubber ¡al loon,to
dlsplace the introduced air space, was performed at 26, 38 and 50 hours
of íncubation (or 0, 12 and 24 hours after windowing). Tables 18 and
19 and FiS. l¡r show that aîr cell reexpansion also reverses the terâtogenic
effect of wîndowing, especlal ly when performed Ímmediately.