in vitro culture and isoenzyme analysis of giardia lamblia

Twenty-four batches of cysts (71 % of 34 excystation trials) excysted successfully
with this method. The overall percent excystation ranged between 2 and 41% and
viability ranged between 30 and 100% by the eosin dye exclusion method.
Addition of Glutathione to the induction medium did not improve the level of
excystation (which remained below 40% in all but one of the excysted samples).
The results of successfully excysted samples (expressed in percentages), their
viabilities as determined by dye-exclusion and total counts are summarised in
Table 3.1. This data was extracted from the full list of all attempted excystations in
Appendix 3. The eosin exclusion method showed higher viability levels (with a
mean percent viability of 75) whilst the mean excystation value was 8,9%.
In most experiments, low levels of excystation were attained. Only in 3 of the 25
successful excystations were the levels of excystation above 30%, the rest were
below 20%.
The method described by AI Tukhi et al. (1991) (3.2.1) was attempted on seven
samples that had been successfully excysted previously using the Hamilton &
Jackson (1990) method. These cyst samples did not excyst using the former
method.
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