From Cruentus Libri Press we have an anthology call for "Under the Knife. They're looking for horror stories of 2500 to 7500 words with a medical setting. They want stories that "subvert the Hippocratic Oath: First do no harm". Deadline is September 30. Payment is shared royalties. You can find the details here http://cruentuslibri.wordpress.com/2012/06/29/open-for-submissions-under-the-knife/
Thanks to Katherine Tomlinson for the link.