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

4S
or 22 KOH. Three types of skeleta¡ defects were recc¡rded în the spine:
a) part¡al or conplete deletions of vertebrae
b) splna biflda manifesta in the region of an open neural defect
c) and spina bifida occulta.
Detalls of skeletal stainÌng and clearance of these older embryos are given
in Appendix B .
4.8 HISTOtOG¡cAt FEATURES OF. NEURAL cLosURE AND NEURAL DEFEcTS
u.r.,|
A representôtlve series of experirnental and control embryos (from
Sectlon 4.6), in good condition at fixation 0 to 42 hours after windowing,
were selected for serial sectioning. 0nly those control embryos showing
normal development and little necrosís were included.
After light staining with eosin in 702 alcohol, embryos were dehydrated
ln 802, 902 and 952 alcohols, processed wíth amyl acetate, and embedded in
pa raff í n wax.
Some !0,000 seríal sect¡ons were cut, gach at a thicknèss of 10 microns,
and stained with hematoxyl ìn and eosin.
4.8,2 Grouplnlqf E¡Þq¿os
Because of the rapid progress of the early part of neurulation (after
Stage B), exper¡nental and control embryos could only be compared ât identical
Stages. ln later neurulation several Stages were combinäd.
As no experimental embryos were available at Stage 9, the four groups
cons ¡ sted of:
Group 1 Stage 10
Group 'l 1 Stages 1 1- l2
Qroup 111 Stases tr3-16
Group 1V Stages I /-20