Exhibit 10.5Loan No.                                         ESTOPPEL CERTIFICATE     The undersigned hereby certifies to PNC Bank, National Association, and its affiliates andtheir respective successors and assigns (“Lender”) that, as of December 21, 2007:1. Aurora Medical Group, Inc., a Wisconsin non-stock corporation (“Tenant”) is or willsoon be the tenant, and NNN Eastern Wisconsin Medical Portfolio, LLC (“Landlord”) isthe current landlord, on the premises commonly knownas                                         (the “Premises”). 2. Tenant is renting the Premises from Landlord pursuant to lease agreement titled Lease, datedDecember 21, 2007 (the “Original Lease”). The Original Lease has not been modified oramended, except asattached:                                                                                                *[tenant may attachcopies of all lease modifications/amendments to this estoppel in lieu of detailing eachmodification/amendment]**.*The Original Lease, as amended or modified, is hereinafterreferred to as the “Lease.” 3. Tenant owns no options to extend the term of the Lease, options to purchase the Premises,rights of first refusal or other rights to acquire an interest in the Premises except as setforth in the Lease. 4. The date upon which the term of the Lease actually commenced was December 21, 2007. TheLease is in full force and effect and is the only agreement between Landlord and Tenantrelating to occupancy of the Premises. The earliest date upon which the Lease expires underthe Lease December 31, 2022. 5. Tenant has accepted possession of and is currently open for business in the Premises, andacknowledges that Landlord has completed all of the improvements required to be made by it, toTenant’s satisfaction. Tenant acknowledges receipt of full payment for any tenant allowanceor similar up-front sum to be paid by Landlord. All conditions to Tenant’s obligation to payall rents and other payments required under the Lease have been satisfied. 6. No one other than Landlord, Tenant, Tenant’s employees, and other occupants or subtenantspermitted under the Lease occupies or has any right to occupy, through Tenant, any part of thePremises. 7. No rent or other payments have been paid, and Tenant agrees that no rent or other paymentswill in the future be paid, more than one (1) month in advance of their due date. 8. As of the date hereof, the minimum rent obligation under the Lease is $                     per monthand the monthly billing for impounds of additional rent for common area
 

 
  expenses, insurance, real estate taxes and the like is $0.00 per month (Tenant is to pay forall such expenses under the terms of the Lease).. Landlord currently holds Tenant nosecurity deposits. 9. There is no existing default or claimed default by either Landlord or Tenant under the Lease.No event has occurred which, with the passage of time or the giving of notice, or both, wouldconstitute a default by either Landlord or Tenant under the Lease. Tenant has no existingdefenses or offsets against Landlord’s enforcement of the Lease. 10. No actions, voluntary or otherwise, are pending against Tenant or any of its general partnersunder any bankruptcy, receivership, insolvency or similar laws of the United States or anystate thereof. 11. To the best of Tenant’s knowledge, its use, maintenance and operation of the Premisescomplies with, and will at all times comply with, all applicable federal, state, county orlocal statutes, laws, rules and regulations of any governmental authorities, including thoserelating to environmental, health or safety matters. Tenant does not and will not engage inany activity which would involve the use of the Premises for the storage, generation, use,treatment, transportation or disposal of any chemical, material or substance which isregulated as toxic or hazardous or exposure to which is prohibited, limited or regulated byany federal, state, county, regional, local or other governmental authority or which, even ifnot so regulated, may or could pose a hazard to the health and safety of the other tenants andoccupants of Landlord’s property, except in quantities common for Tenant’s business and incompliance with applicable law. 12. Tenant agrees to give to Lender, by certified mail, or by Federal Express or other comparableovernight delivery service, addressed to:PNC Bank, National Association