[R] Partial proportional odds logistic regression

[Inman, Brant A. M.D.]

R-experts:

I would like to explore the partial proportional odds models of Peterson
and Harrell (Applied Statistics 1990, 39(2): 205-217) for a dataset that
I am analyzing.  I have not been able to locate a R package that
implements these models.  Is anyone aware of existing R functions,
packages, etc... that might be used to implement the partial
proportional odds models?

Brant Inman