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                                                                   EXHIBIT 10.28


                        GUARANTY AND SURETYSHIP AGREEMENT

         FOR VALUE RECEIVED and intending to be legally bound, in consideration
of credit given, or to be given, advances made or to be made, or other financial
accommodations from time to time afforded or to be afforded to Borrower (as
hereinafter defined), the undersigned (the "Guarantor") hereby, unconditionally
and irrevocably guarantees and becomes surety to Bank of America, N.A., its
successors and assigns ("Bank"), for the due and punctual payment and
performance of the Obligations (as hereinafter defined), as and when such
payment or performance shall respectively become due, payable, and/or performed
in accordance with the terms of the Obligations, whether at maturity or by
declaration, acceleration, or otherwise. This Agreement is executed and
delivered pursuant to the Loan Agreement (as hereinafter defined). Capitalized
terms not otherwise defined herein shall have the meanings ascribed to such
terms in the Loan Agreement.

                                 I. DEFINITIONS

         As used herein, the following terms shall have the indicated meanings:

         "Agreement" means this Guaranty and Suretyship Agreement and all
modifications, renewals, extensions, and amendments hereto.

         "Borrower" means ARC Worcester Center, L.P., a Tennessee limited
partnership.

         "Collateral" means the collateral securing, or which may in the future
secure the Obligations.

         "Loan Agreement" means that certain Loan and Security Agreement of even
date herewith, among the Borrower, Bank and Guarantor, together with any
amendments, renewals, extensions, or restatements thereof.

         "Note" means the Promissory Note of even date herewith, in the original
principal amount of $1,000,000, made by Borrower and payable to Bank, together
with all amendments, renewals and extensions thereof.

         "Obligations" means and includes (i) all indebtedness of Borrower to
Bank evidenced by the Note, and all other indebtedness of Borrower to Bank,
whether such indebtedness is direct or indirect, absolute or contingent, joint
or several, together with any and all indebtedness created or incurred under any
extension, renewal, refinancing, or refunding of such indebtedness in whole or
in part, whether on account of principal, interest, or otherwise (including,
without limitation, any



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interest which accrues after the commencement of any case, proceeding, or other
action relating to the bankruptcy, insolvency, or reorganization of Borrower),
(ii) payment, performance, and discharge of all other obligations of Borrower
under the Loan Documents, (iii) all costs and expenses, including without
limitation reasonable attorneys' fees, incurred by Bank in the collection or
attempted collection of any indebtedness included in the Obligations, and in the
administration of the Obligations, and (iv) all future advances made by Bank for
the maintenance, preservation, protection, or enforcement of, or realization
upon, the property subjected and intended to be subjected to the lien and
security interest in the Collateral, or any portion thereof, including without
limitation advances for storage, transportation charges, taxes, insurance,
repairs, and the like.

                                  II. COVENANTS

         1. The obligations of Guarantor under this Agreement shall be
continuing, absolute, and unconditional and shall remain in full force and
effect without regard to, and shall not be released, discharged, or in any way
affected by: (1) any amendment, extension, modification of, or supplement to the
Loan Documents, including without limitation an increase in the principal
indebtedness evidenced by the Note; (2) any exercise or nonexercise of or delay
in exercising any right, remedy, power, or privilege under or in respect of this
Agreement, the Loan Agreement, or any of the other Loan Documents (even if any
such right, remedy, power, or privilege shall be lost thereby), or any waiver,
consent, indulgence, or other action or inaction in respect thereof; (3) any
lack of diligence, failure, neglect, or omission on the part of Bank to make any
demand or protest or to give any notice of dishonor or default; (4) any failure
or omission of Bank to realize upon or protect any of the Collateral, to
exercise or enforce any lien upon the Collateral, or to exercise any right of
set-off; (5) any bankruptcy, insolvency, arrangement, composition, assignment
for the benefit of creditors, or similar proceeding commenced by or against
Borrower or Guarantor; (6) any failure to perfect or continue perfection of, or
any release or waiver of, any rights given to Bank with respect to any property
as security for the performance of any of Borrower's or Guarantor's obligations
under the Loan Agreement, the Note, or any other Loan Document; (7) any
extension of time for payment or performance of any of the Obligations; (8)
dissolution (voluntarily or involuntarily) of Guarantor; (9) the genuineness,
validity, or enforceability of the Loan Documents; (10) any limitation of
liability of Borrower or Guarantor contained in the Loan Documents; (11) any
defense that may arise by reason of the failure of Bank to file or enforce a
claim against the Borrower or Guarantor in any bankruptcy or other proceeding;
(12) the voluntary or involuntary liquidation, dissolution, sale of all or
substantially all of the property of Borrower or Guarantor, the marshalling of
assets and liabilities, or other similar proceeding affecting Borrower or any of
its assets; (13) the release of Borrower or Guarantor from the performance or
observance of any of the agreements, covenants, terms, or conditions contained
in the Loan Documents by


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operation of law; (14) the release or discharge of any other surety or guarantor
of the Obligations; or (15) any other circumstances which might otherwise
constitute a legal or equitable discharge of, or defense available to, a
guarantor or surety.

         2. Guarantor agrees that so long as this Agreement is in effect
Guarantor will maintain Guarantor's corporate existence and will not dissolve or
otherwise dispose of all or substantially all of Guarantor's assets.

                                  III. WAIVERS

         1. Guarantor hereby waives and agrees not to exercise any rights which
it may acquire by way of subrogation or reimbursement under this Guaranty as a
result of any payment made hereunder or otherwise.

         2. Guarantor hereby waives (a) any presentment for payment, notice of
nonpayment, demand, protest, or notice of acceptance of this Agreement, (b) any
right to notice of advances made to Borrower from time to time under the
provisions of the Loan Documents, and (c) any notice of any matters described or
referred to in Article II above.

         3. Guarantor hereby further waives any and all notice of every kind to
which Guarantor might otherwise be entitled with respect to the incurring of any
further or increased obligation or liability by Borrower to Bank, the demand for
payment or the payment of all or any obligations or liabilities of the Borrower
or Guarantor to Bank (whether now existing or hereafter arising) or the
presentment of any instrument for payment at any time in connection with any
obligation or liability of the Borrower or Guarantor or the protest or
nonpayment thereof. Guarantor hereby further waives, surrenders, and agrees not
to claim or enforce (i) any right to be subrogated in whole or in part of any
right or claim of Bank against the Borrower or Guarantor arising under the Loan
Documents or any other collateral given to Bank as security for the payment or
performance of the Obligations and (ii) any right to require the marshalling of
any assets of the Borrower or Guarantor, which right of subrogation or
marshalling might otherwise arise from any partial payment of the Obligations by
Guarantor. Guarantor hereby further waives all applicable statutes of limitation
which may exist at any time in favor of Guarantor.

                       IV. REPRESENTATIONS AND WARRANTIES

         Guarantor represents, warrants, and covenants to and with Bank that:

         1. Guarantor acknowledges that this Agreement is necessary to induce
Bank to advance the credit for the Obligations and Guarantor is willing and able
to


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deliver this Agreement because Guarantor will receive direct and material
benefit from Bank's extension of credit to Borrower.

         2. Guarantor is now and will be completely familiar with the business,
operations, and condition of Borrower and Guarantor hereby waives and
relinquishes any duty on the part of Bank to disclose any matter, fact, or thing
relating to the business, operation, or condition of Borrower now known or
hereafter known by Bank.

                           V. DEFAULT AND ENFORCEMENT

         1. In addition to all liens upon and rights of set-off against moneys,
securities, or other property of Guarantor given to Bank by law or equity, Bank
shall have a lien upon, security interest in, and right of immediate set-off
against all moneys, instruments, notes, bonds, commercial paper, securities, and
other property of Guarantor now or hereafter in the possession of or on deposit
with Bank, whether held in a general or special account for deposit,
safe-keeping, or otherwise. Every such lien and right of set-off may be
exercised after the occurrence of an Event of Default under the Loan Agreement
(and expiration of all notice and cure periods), or a default by Guarantor under
this Agreement, and expiration of applicable cure periods, without further
notice or demand to Guarantor, and Bank may sell or cause to be sold, at public
or private sale, in any manner and place which may be lawful, for cash or credit
and upon such terms as Bank may see fit, and without demand or notice to
Guarantor, all or any of such property, and Bank or any other person may
purchase such property, rights, or interests so sold and thereafter hold the
same free of any claim or right of whatsoever kind, including any right of
equity or redemption of Guarantor, such demand, notice, or right of equity or
redemption being hereby expressly waived and released.

         2. Each and every right, remedy, and power hereby granted to Bank or
allowed it by law or other agreement shall be cumulative and not exclusive of
any other, and may be exercised by Bank at any time and from time to time. In
the event that the Obligations of Borrower to Bank exceed in any respect any
amount by which this Agreement may be limited, any payments by Borrower, or any
collections or recovery by Bank from any sources other than this Agreement, may
be applied first by Bank to any portion of the Obligations which exceeds the
limits of this Agreement.

         3. Notwithstanding anything contained in this Agreement or in the Loan
Documents to the contrary, Guarantor shall be in default under this Agreement
upon the occurrence of an Event of Default under the Loan Agreement (and
expiration of applicable cure periods). Upon the occurrence of any such default,
Bank may, at its option, accelerate the indebtedness evidenced and secured by
the Loan Documents.


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         4. This shall be an agreement of suretyship as well as of guaranty, and
Bank may proceed directly against Guarantor whenever any payment or performance
required pursuant to the Obligations is not made or rendered to Bank without
being required to make demand upon or proceed first against Borrower or any
other person or entity, or against any security for Borrower's or Guarantor's
Obligations under the Loan Documents or hereunder, or exhaust its remedies
against Borrower or any other surety or guarantor. It is expressly agreed that
Bank may at any time following an Event of Default under the Loan Agreement or a
default by Guarantor hereunder, make demand for payment on, or bring a claim
against, Guarantor.

         5. If Bank employs counsel to enforce this Agreement by suit or
otherwise, Guarantor will reimburse Bank, upon demand, for all expenses incurred
in connection therewith (including, without limitation, reasonable attorneys'
fees), whether or not suit is actually instituted.

         6. Guarantor irrevocably: (a) agrees that Bank or any other holder or
holders of the Note may bring suit, action, or other legal proceedings arising
out of this Guaranty or the transactions contemplated hereby in the courts of
the State of Tennessee, sitting in Nashville, Davidson County, Tennessee, or the
courts of the United States for the Middle District of Tennessee, sitting in
Nashville, Davidson County, Tennessee, but shall not be restricted to such
courts; (b) consents to the jurisdiction of each such court in any such suit,
action, or proceeding; and (c) waives any objection which Guarantor may have to
the laying of the venue of any such suit, action, or proceeding in any of such
courts.

                             VI. GUARANTY LIABILITY

         1. Guarantor's obligations hereunder and under the other Loan Documents
shall be in an amount (such amount being referred to herein as the "Maximum
Guaranty Liability") equal to, but not in excess of, the maximum liability
permitted under Title 11 of the United States Code, any other state or federal
laws governing bankruptcy, suspension of payments, reorganization, arrangement,
adjustment of debts, dissolution, insolvency, relief of debtors or creditors'
rights and any other similar laws ("Applicable Bankruptcy Law"). To the extent
such obligations otherwise would be subject to avoidance under Applicable
Bankruptcy Law, if Guarantor is deemed not to have received valuable
consideration, fair value or reasonably equivalent value for its obligations
hereunder or under the other Loan Documents, Guarantor's obligations hereunder
and under the other Loan Documents shall be reduced to that amount which, after
giving effect thereto, would not render Guarantor insolvent, or leave Guarantor
with an unreasonably small capital to conduct its business, or cause Guarantor
to have incurred debts (or to be deemed to have intended to incur debts), beyond
its ability to pay such debts as they mature, at the time such obligations are
deemed to


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have been incurred under Applicable Bankruptcy Law. As used herein, the terms
"insolvent" and "unreasonably small capital" shall likewise be determined in
accordance with Applicable Bankruptcy Law. This Paragraph 1 is intended solely
to preserve the rights of the Bank hereunder and under the other Loan Documents
to the maximum extent permitted by Applicable Bankruptcy Law, and neither the
Guarantor nor any other person or entity shall have any right or claim under
this Paragraph 1 that otherwise would not be available under Applicable
Bankruptcy Law. Guarantor agrees that the Obligations at any time and from time
to time may exceed the Maximum Guaranty Liability of Guarantor, without
impairing this Guaranty or affecting the rights and remedies of the Bank
hereunder.

                               VII. MISCELLANEOUS

         1. In the event Bank is required at any time to refund or repay to any
person for any reason any sums collected by it on account of the obligations
subject to this Agreement, including but not limited to sums repaid to a Trustee
in Bankruptcy as a result of an avoided preferential transfer or fraudulent
conveyance, Guarantor agrees that all such sums shall be subject to the terms of
this Agreement and that Bank shall be entitled to recover such sums from
Guarantor notwithstanding the fact that this Agreement previously may have been
returned to Guarantor or that Guarantor previously may have been discharged from
further liability under this Agreement.

         2. Any notice, demand, or request by Bank to Guarantor or by Guarantor
to Bank shall be in writing and shall be given in accordance with the Loan
Agreement.

         3. This Agreement constitutes the entire agreement, and supersedes all
prior agreements and understandings, both written and oral, between Guarantor
and Bank with respect to the subject matter hereof. If any clause, provision, or
section of this Agreement is determined to be illegal or invalid by any court,
the invalidity of such clause, provision, or section shall not affect any of the
remaining clauses, provisions, or sections hereof and this Agreement shall be
construed and enforced as if such illegal or invalid clause, provision, or
section had not been contained herein. In case any agreement or obligation
contained in this Agreement be held to be in violation of law, then such
agreement or obligation shall be deemed to be the agreement or obligation of
Guarantor, as the case may be, to the full extent permitted by law.

         4. No set-off, claim, reduction, or diminution of any obligation or
defense of any kind or nature, which Guarantor or Borrower has or may have
against Bank, shall be available hereunder to Guarantor against Bank.



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         5. No act of commission or omission of any kind or at any time on the
part of Bank in respect of any matter whatsoever shall in any way effect or
impair this Agreement. This Agreement is in addition to and no in substitution
for or discharge of any other suretyship held by Bank.

         6. This Agreement shall be construed and enforced in accordance with,
and the rights of the parties shall be governed by, the laws of the State of
Tennessee. The invalidity or unenforceability of any one or more phrases,
sentences, clauses, or provisions in this Agreement shall not affect the
validity or enforceability of the remaining portions of this Agreement or any
part thereof.

         7. This Agreement shall bind Guarantor and Guarantor's successors and
assigns and the benefits hereof shall inure to its successors and assigns. Bank
may, without any notice whatsoever to Guarantor, sell, assign, or transfer all
or any part of the Obligations, and in that event each and every immediate and
successive assignee, transferee, or holder of all or any part of the Obligations
shall have the right to enforce this Agreement, by suit or otherwise, for the
benefit of such assignee, transferee, or holder, as fully as though such
assignee, transferee, or holder were herein by name given such rights, powers,
and benefits; provided, however, that Bank shall have an unimpaired right, prior
and superior to that of any assignee, transferee, or holder, to enforce this
Agreement for the benefit of Bank as to so much of the Obligation that Bank has
not sold, assigned, or transferred.


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         WITNESS the due execution hereof this 9th day of November, 1999.


SYMBION AMBULATORY RESOURCE CENTRES, INC.



BY:      /s/ Jeff Bogle
    -------------------------------------

TITLE: Chief Financial Officer
       ----------------------------------












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