Findings:

• The Sentinel (user)
• North Sentinel Island
• Dragon Quest IX: Sentinels of the Starry Skies
• Mr. Blocky - Tron Sentinel version
• The inhospitable inhabitants of North Sentinel Island
• Milwaukee Journal Sentinel
• Operation Vigilant Sentinel
• sentinel value
• TIE Sentinel
• Progen
• sentinel lymph node biopsy
• sentinel node
• The Sentinel
• Sentinel (user)
• Sentinel

If you Log in you could create a "Progen Sentinel" node. If you don't already have an account, you can register here.