Unable to use `eval(parse(text))' in nlme::lme

I would like to run lme() on a number of response variables 
in a dataframe in an automatic manner.  Bu, when I
use eval(parse(text=yname)) to denote the LHS of the formula in lme(), 
I get the following error message:

require(nlme)

mod2 <- with(subset(labdata2, Transplant_type!=0 & time >0), 

lme(eval(parse(text=yname)) ~ time + 
as.factor(gvhd), random = ~1|Patient, correlation = corAR1(), 
method="ML", na.action=na.omit))
Error in model.frame.default(formula = ~Patient + yname + time + gvhd,  :
  variable lengths differ (found for 'yname')

The same usage works well in lme4::lmer without any problems.

It seems that there is a problem in 
how the formula object is evaluated in lme().  Is there an alternative way
to do this?