To circumvent spam filters, many spammers attempt to obfuscate their emails by deliberately misspelling words or introducing other errors into the text. For example viagra may be written vigra, or mortgage written m0rt gage. Even though humans have little difficulty reading obfuscated emails, most content-based filters are unable to recognize these obfuscated spam words. In this paper, we prese...

Clinical studies have demonstrated that sildenafil citrate (Viagra) is an effective and well-tolerated oral treatment for erectile dysfunction. Despite its established safety profile, concern about its cardiovascular safety persists among some physicians and the general public. This concern has stemmed primarily from sporadic reports of adverse events published in the literature and sensational...

Sildenafil is a selective inhibitor of phosphodiesterase type 5 and is used for the treatment of male erectile dysfunction. It causes relaxation of vascular smooth muscle via a cyclic guanosine monophosphate (cGMP) second messenger that results in a vasodilatory effect in the corpus cavernosum. A dilatory effect on peripheral blood vessels has also been identified and vascular side effects prim...

In 1998, the world was formally introduced to Viagra (sildenafil), the first oral agent to be approved in the United States for the treatment of erectile dysfunction. Developed by Pfizer chemists, sildenafil inhibited phosphodiesterase type 5 (PDE5), one of the 11-member superfamily of enzymes that hydrolyze cyclic nucleotide monophosphates and among the first discovered that was selective for ...