Extracting information from PubMed

I'm working on some analysis of PubMed data and have run into some difficulties.

• Corresponding author

I can't find any way to identify the "corresponding" author in a pubmed record
I dont' think is correct to simply use the last author.
There is sometimes an email address in the affiliations tag, but no way to tell which author it corresponds to.

• Author institutions

There is an affiliation section, but it's not complete and there's no way to tell which author it corresponds to.

• Author names

Sometimes authors are listed with first and last names, sometimes the first name is just initials though. It's not always easy to infer this

Anybody know how to acquire this information?