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                                                                  EXHIBIT 10.3.6


                               SUBLEASE AGREEMENT

                         SAN JACINTO METHODIST HOSPITAL
                                 BAYTOWN, TEXAS

         This SUBLEASE AGREEMENT is made and entered into as of the 1st day of
Nov. 1991 by and between SAN JACINTO METHODIST HOSPITAL, a Texas nonprofit
corporation ("Lessee") and C. A. Riser, M.D. ("Sublessee").

                              W I T N E S S E T H

         WHEREAS, Lessee has leased certain net rentable space in the Baker
Court Building 4308 Garth Rd. Baytown, Texas (the "Building") from Piping Rock
Corporation (the "Lessor"), owner of the Building and

         WHEREAS, Lessee desires to sublease the space in the Building and
provide certain other services to the Tenant who is on the Medical Staff at San
Jacinto Methodist Hospital (the "Hospital") in Baytown; and

          WHEREAS, Lessee desires to sublease space in the Building for
Sublessee's medical office practice and Sublessee also wishes to obtain the
other services offered by Lessee as enumerated in this Sublease Agreement;

         NOW, THEREFORE, for and in consideration of the mutual covenants
contained herein, the parties to this Sublease Agreement agree to as follows:

I.       Sublease of Premises

         1.1.       Rented Space. Lessee hereby subleases to Sublessee 4,784
                    square feet (the "Premises") located in the Building.

         1.2.       Adjustments to Rented Space. The exact amount of square
                    feet comprising the Premises may be enlarged or reduced at
                    such later date when Sublessee approves the floor plans for
                    the Premises.

II.      Rent

         2.1.       Basic Rent. The rental rate for the Premises shall equal
                    $0.06 per month for each square foot of net rentable area
                    subleased by Sublessee under terms and provisions hereof.

         2.2.       Rent Payable. Except as otherwise provided herein, monthly
                    rent shall be due and payable to Sublessor on the first day
                    of each calendar month during the term of this Sublease
                    Agreement.
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         2.3.       Late Charge. In the event any rent due and payable by
                    Sublessee is not received by Lessee within ten days after
                    it is due, Lessee may, at its discretion, charge interest
                    on the delinquent amount at the maximum legal rate from the
                    date due until the date paid.

         2.4.       Prorated Rent. If Sublessee's occupancy shall commence on a
                    date other than the first day of a calendar month, then
                    rent will be prorated for that month and the last month of
                    the term of this Sublease Agreement.

III.     Use

         3.1.       Permitted Use. Sublessee may use and occupy the Premises
                    only for the purpose of operating a medical office practice
                    and purposes ancillary thereto. Sublessee agrees that
                    Sublessee and Sublessee's agents, employees and invitees
                    will at all times comply fully with the rules and
                    regulations of the Building from time to time adopted by
                    Lessor and Provided to Sublessee.

         3.2.       Continued Use. Sublessee agrees to maintain an active
                    full-time medical practice on the Premises at all times
                    during the term of this Sublease. "Maintaining an active
                    full-time medical practice" shall mean that Sublessee shall
                    conduct a medical office practice on Premises with a full
                    staff of employees during those regularly scheduled
                    business hours that are common and appropriate to a full-
                    time medical practice. Failure to maintain an active
                    medical practice on the Premises shall constitute a default
                    of this Sublease Agreement.

         3.3.       Common Areas. Sublessee and Sublessee's agents, employees
                    and invitees shall have the revocable, nonexclusive license
                    in common with others permitted by Lessor, to use the
                    common areas of the Building as they, may from time to time
                    exist, but all such common areas will remain within the
                    exclusive control of Lessor.

         3.4.       Access by Sublessor. Lessee may at any time, without
                    liability, enter the Premises for inspection, to supply
                    janitorial or other services, for emergency entry or to
                    alter or repair the premises or any portion of the
                    Building. No provision of this Sublease Agreement shall be
                    construed as obligating Lessee to perform any repairs,
                    alterations or decorations at the request of Sublessee,
                    except as otherwise expressly herein agreed to be performed
                    by Lessee.

IV.      Laboratory, Radiology and Hospital Services

         4.1.       Laboratory and Radiology Services. Lessee agrees to provide
                    laboratory and radiology services for non-Medicaid patients
                    at the discounted rates listed on the Schedules attached
                    hereto. These prices are subject to renegotiation and
                    extension each January.

         4.2.       Relationship to Hospital. Although the Lessee hopes that
                    the quality and cost-effective nature of the Hospital's
                    services will commend themselves to the Sublessee's
                    patients, it is clearly understood that the choice of
                    services and
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                    the choice of service suppliers that the Sublessee makes on
                    behalf of the Sublessee's patients must be, and will be
                    made only with regard to the best interest of patients
                    themselves. Therefore, so that there will be no
                    misunderstanding, Lessee and Sublessee specifically
                    acknowledge that the Sublessee's initial and continued
                    ability to sublease space in the Building in no way
                    requires and in no way is contingent upon the admission,
                    recommendation, referral, or any other form of arrangement
                    by the Sublessee for utilization by patients or others of
                    any item or service offered by the Hospital.

V.       Noncompetition

         5.1.       Covenant Not to Compete. Sublessee recognizes (i) that
                    Lessee's entering into this Sublease Agreement to provide
                    the services offered hereby is induced by the covenants and
                    assurances made by Sublessee, (ii) that Sublessee's
                    covenant not to compete is necessary to ensure the
                    continuation of Lessee's business and (iii) that
                    irreparable harm and damage will be done to Lessee in the
                    event that Sublessee competes with Lessee within the area
                    or areas described in this Section. Therefore, Sublessee
                    agrees that during the term of this Sublease Agreement,
                    Sublessee will not, directly or indirectly, own, manage,
                    operate, control or participate in the management or
                    control of, be employed by or retained to provide services
                    for, lend Sublessee's name to, or maintain or continue any
                    interest whatsoever in, another medical office building or
                    any enterprise within Lessee's primary and secondary
                    service areas offering services similar to those offered by
                    Lessee, including, but no limited to, laboratory services,
                    radiology services and hospital services. Notwithstanding
                    the foregoing, this section shall not be construed to
                    prohibit membership on a hospital medical staff.

         5.2.       Existing Competition. The foregoing covenant not to compete
                    shall not apply to the following interests presently held
                    by Sublessee:

                    -----------------------------------------------------------
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                    -----------------------------------------------------------
                    -----------------------------------------------------------

VI.      Other Services, Utilities and Taxes.

         6.1.       Services and Utilities Provided. Lessee agrees to furnish
                    during reasonable hours of generally recognized business
                    days (to be determined by Lessee) electricity, gas, water
                    heating and air conditioning for ordinary uses, and
                    elevator, janitorial and sewage services.

         6.2.       Direct Obligations of Sublessee. Sublessee shall be
                    responsible for all telephone and other utility services
                    billed directly to Sublessee, and for all
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                    property taxes assessed against Sublessee's leasehold
                    improvements and personal property located in the Premises.

VII.     Finish-Out Alterations and Maintenance and Repairs.

         7.1.       Initial Finish-Out. Initial finish-out of the Premises
                    shall be by mutual consent of Lessee and Sublessee.

         7.2.       Subsequent Alterations. Sublessee may not make any
                    subsequent alterations, additions or improvements to the
                    Premises without first obtaining Lessee's written consent
                    (except for installation of unattached, movable equipment
                    or furniture that may be installed without drilling,
                    cutting or otherwise defacing the Premises.)

         7.3.       Maintenance and Repairs. Lessor shall, at its expense,
                    maintain the roof, foundation and the structural soundness
                    of the exterior walls of the Building, including the
                    Premises and the common areas, in good repair and
                    condition, reasonable wear and tear excepted, and except
                    for repairs occasioned by the acts or omissions of
                    Sublessee, its patients, employees, licensees or
                    concessionaires (unless such act or omission results in
                    damage covered by valid and collectible fire and extended
                    coverage insurance policies and is collectible thereunder).

VIII.    Term, Termination and Default.

         8.1.       Term. The term of this Sublease Agreement shall be for a
                    period of three (3) years, beginning on the day Sublessee
                    moves into the Premises.

         8.2.       Default. The following events shall be deemed to be events
                    of default by Sublessee under this Agreement;

                                  (i)      failure to pay rent under this
                          Sublease Agreement, and such failure continues for a
                          period to ten days thereafter;

                                  (ii)     failure to maintain an active
                          medical practice on the Premises as required by
                          Section 3.2 of this Sublease Agreement;

                                  (iii)    permanent desertion or vacation of
                          any substantial portion of the Premises; and

                                  (iv)     failure to comply with the covenant
                          not to compete as required by Section V of this
                          Sublease Agreement.

         8.3.       Remedies Upon Default. Upon the occurrence of any event of
                    default, Lessee shall have the right, in addition to any
                    other rights Lessee may have, at law or in equity to
                    terminate this Sublease Agreement. Upon such termination,
                    Sublessee shall surrender the Premises to Lessee, and if
                    Sublessee fails to do so, Lessee may, without prejudice to
                    any other remedy that it may have for possession or
                    arrearages in the payment of rent, enter
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                    the Premises and take possession of the premises and any
                    equipment and personal property located therein, and expel
                    or remove Sublessee and any other person who may be
                    occupying the Premises or any part thereof, by force if
                    necessary, without being liable for prosecution or any
                    claim of damages therefor.

IX.      Insurance and Liability.

         9.1.       Insurance. Sublessee shall procure and maintain, at its sole
                    cost and expense, throughout the term of this Sublease
                    Agreement, a policy or policies of general liability and
                    malpractice insurance, including, without limitation,
                    professional liability, insuring both Lessee and Sublessee
                    against all claims, demands or actions arising out of or in
                    connection with the operation or maintenance of the
                    Premises, with limits of such policy or policies to be in
                    amounts not less than One Hundred Thousand Dollars
                    ($100,000) per occurrence and Three Hundred Thousand
                    Dollars ($300,000) in the aggregate per annum. Each of the
                    policies described herein shall be written, to the extent
                    practicable, on standard forms customarily used in Harris
                    County, Texas, and shall contain (i) the agreement of the
                    insurer to give Lessee at least thirty (30) days written
                    notice prior to cancellation of or material change in such
                    policies or any of them and (ii) waiver of subrogation
                    rights against Lessee. Sublessee shall furnish Lessee with
                    a duplicate copy of all policies of insurance (or
                    certificates therefor.)

                    9.2.       Liability. Lessee shall not be liable to
                    Sublessee or to Sublessee's patients, employees, agents or
                    visitors, or to any other person or persons for any injury
                    or death to such persons or age to property on or about the
                    Premises caused by the negligence or misconduct of
                    Sublessee. Sublessee agrees to indemnify Lessee and hold
                    Lessee harmless from any loss, liability, claims, demands,
                    causes of action or expense, including attorneys' fees
                    arising out of any such damage, death, or injury; except
                    death or injury to persons or damage to property due to the
                    negligence or misconduct of the Lessee.  Lessee agrees to
                    indemnify Sublessee and hold Sublessee harmless from any
                    loss, liability, claims, demands, causes of action or
                    expenses, including attorneys' fees, arising out of damage,
                    death, or injury caused by the negligence or misconduct of
                    Lessee; except death or injury to persons or damage to
                    property due to the negligence or misconduct of Sublessee.

X.       Miscellaneous.

         10.01.     Assignment and Subletting. Sublessee shall not have the
                    right to assign this Sublease Agreement or to sublet the
                    whole or any part of the Premises, without the prior
                    written consent of Lessee and Lessor. Notwithstanding any
                    permitted assignment or subletting, Sublessee shall at all
                    times remain fully responsible and liable for the payment
                    of rent herein specified and for compliance with all of
                    Sublessee's other obligations under the terms and
                    conditions of this Sublease Agreement. Assignment with the
                    consent of Lessee shall be conditioned upon the written
                    acceptance by the prospective assignee of all the terms of
                    this Agreement. Lessee shall have the right to
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                    assign any of its rights and obligation under this Sublease
                    Agreement.

         10.02.     Legal Fees and Costs. In the event either party elects to
                    incur legal expenses to enforce or interpret any provision
                    of this Sublease Agreement, the prevailing party will be
                    entitled to recover such legal expenses, including, without
                    limitation, attorneys' fees, costs and necessary
                    disbursements, in addition to any other relief to which
                    such party shall be entitled.

         10.03.     Choice of Law and Venue. The parties agree that this
                    Sublease Agreement shall be governed by and construed in
                    accordance with the laws of the State of Texas, and that
                    the federal and/or state courts located in Harris County,
                    Texas shall be the exclusive courts of jurisdiction and
                    venue for any litigation, special proceeding or other
                    proceedings as between parties that may be brought, or
                    arise out of, in connection with or by reason of this 
                    Agreement.

         10.04.     Notice. Any notice, demand or communication required,
                    permitted, or desired to be given hereunder shall be deemed
                    effectively given when personally delivered or mailed by
                    prepaid certified mail, return receipt requested, to the
                    addresses following the signatures to this Sublease
                    Agreement.

         10.05.     Severability. In the event any provision of this Sublease
                    Agreement is held to be invalid, illegal or unenforceable
                    for any reason and in any respect, such invalidity,
                    illegality, or unenforceability shall in no event affect,
                    prejudice or disturb the validity of the remainder of this
                    Sublease Agreement, which shall be and remain in full force
                    and effect, enforceable in accordance with its terms.

         10.06.     Gender and Number. Whenever the context of this Sublease
                    Agreement requires, the gender of all words herein shall
                    include the masculine, feminine and neuter, and the number
                    of all worlds herein shall include the singular and plural.

         10.07.     Divisions and Headings. The divisions of this Sublease
                    Agreement into sections and subsections and the use of
                    captions and headings in connection therewith are solely
                    for convenience and shall have no legal effect in
                    construing the provisions of this Sublease Agreement.

         10.08.     Waiver of Breach. The waiver by either party of a breach or
                    violation of any provision of this Agreement shall not
                    operate as, or be construed to be, a waiver of any
                    subsequent breach of the same of other provision hereof.

         10.09.     Entire Agreement/Amendment. This Sublease Agreement
                    supersedes all previous contracts and constitutes the
                    entire agreement of whatsoever kind or nature existing
                    between or among the parties respecting the within subject
                    matter and no party shall be entitled to benefits other
                    than those specified herein. As between or among the
                    parties, no oral statements or prior written material no
                    specifically incorporated or referenced herein shall be of
                    any force and effect. The parties specifically acknowledged
                    that in entering into
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                    and executing this Sublease Agreement, the parties rely
                    solely upon the representations and agreements contained in
                    this Sublease Agreement and no others. All prior
                    representations or agreements, whether written or verbal,
                    not expressly incorporated or referenced herein are
                    superseded and no changes in or additions to this Sublease
                    Agreement shall be recognized unless and until made in
                    writing and signed by all parties hereto.



         IN WITNESS WHEREOF, Lessee and Sublessee have each caused this
Agreement to be executed and to be effective as of the day and year first above
written.


         LESSEE:                              SAN JACINTO METHODIST HOSPITAL   
            
                                        
                                        
                                           By: /s/ROD SEIDEL
                                               -----------------------
                                               Rod Seidel
                                               President
                                               4401 Garth Road
                                               Baytown, Texas 77521
                                           
         SUBLESSEE: 

                                           By: /s/Dr. C.A. Riser
                                               ------------------------
                                               Dr. C.A. Riser
                                               Print Name and Title
                                               4308 Garth Rd.
                                               -----------------------
 
                                               Address
                                               Baytown, TX  77021
                                               -----------------------
 
                                               City, State  Zip Code