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                                                                   EXHIBIT 10.37


                     BRITWILL ACQUISITION PROMISSORY NOTE A

Principal Amount:
$1,238,200.00                                             As of January 31, 1999


         1. Promise to Pay. For value received, RAINTREE HEALTHCARE CORPORATION,
fka Unison HealthCare Corporation, a Delaware corporation ("Maker"), with an
address at 15300 North 90th Street, Suite 100, Building A, Scottsdale, Arizona
85260 ("Maker"), promises to pay to the order of BRITWILL INVESTMENTS COMPANY,
LTD., fka Whitehead Family Investments, Ltd., a Texas limited partnership
("Payee"), at 25 Highland Park Village, Suite 100-372, Dallas, Texas 75205,
Attn: Bruce H. Whitehead, or at such other address in the State of Texas as the
holder of this Note at any given time ("Holder") may designate by notice to
Maker, or at the option of Holder by federal funds wire transfers as requested
by Holder by notice to Maker, in lawful money of the United States of America,
the Principal Amount set forth above, together with interest as provided in this
Note.

         2. Definitions. As used in this Note the term(s):

            (1) "Business Day" means a day which is not a Saturday, Sunday,
federally recognized holiday, or day on which banking institutions are not
required to be open in Arizona or Texas;

            (2) "Default Rate" means 9.75% per annum;

            (3) "Event of Default" means (i) failure by Maker to pay any
principal or interest pursuant to this Note on or before the day it becomes due
and payable, (ii) failure by Maker to pay when due principal, interest or
premium in an aggregate amount of $5,000,000.00 or more with respect to any
indebtedness of Maker or any Subsidiary, or the acceleration prior to its
express maturity of any such Indebtedness aggregating $5,000,000.00 or more,
(iii) if a court of competent jurisdiction renders a final judgment or judgments
which can no longer be appealed for the payment of money in excess of
$5,000,000.00 (which are not paid or covered by third party insurance by
financially sound insurers that have not disclaimed or threatened to disclaim
coverage) against Maker or any Subsidiary and such judgment remains undischarged
for a period of 60 consecutive days during which a stay of enforcement of such
judgment shall not be in effect, (iv) if an order for relief is entered against
Maker or any Subsidiary after the Effective Date under any chapter of the
federal Bankruptcy Code, (v) if a court of competent jurisdiction enters an
order or decree appointing a receiver, trustee, liquidator or similar official
for all or substantially all of the property of Maker or any Subsidiary, or
orders the liquidation of Maker or any Subsidiary, and in either case the order
or decree remains unstayed and in effect for 60 consecutive days, (vi) if Maker
fails to maintain in existence its corporate existence, except as a result of a
consolidation or merger with or into another entity where the surviving entity
is a corporation organized and existing under the laws of the United States or
any state thereof or the District of Columbia which expressly assumes in writing
Maker's
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obligations under this Note at a time when no uncured Event of Default exists
and whereby immediately after giving effect to such transaction on a pro-forma
basis the surviving corporation has a consolidated net worth at least equal to
the consolidated net worth of Maker immediately prior to such transaction, or
(vii) if a court of competent jurisdiction enters an order or decree that a
transfer of property of Maker or any Subsidiary of a value in excess of
$5,000,000.00 constitutes a fraudulent transfer under any applicable state law;

            (4)  "Effective Date" has the meaning provided by the Plan, i.e.,
the date of this Note;

            (5)  "Effective Rate" means (i) the Note Rate at all times prior to
the Maturity Date, and (ii) the Default Rate at all times after the Maturity
Date;

            (6)  "Indiana Returned Facility Note" has the meaning provided by
the Plan;

            (7)  "LBO Transaction" means any transaction or series of related
transactions whereby, directly or indirectly, the acquisition of a majority or
controlling equity interest in Maker (or any successor to Maker by merger,
consolidation or otherwise) is, to any material degree, financed by indebtedness
which is the obligation of (or is secured by any property of) Maker or any such
successor or any Subsidiary;

            (8)  "LBO Transaction Date" means the effective date of any LBO
Transaction, provided that, no LBO Transaction Date will occur unless the Senior
Notes are or have then been fully paid (including payment from the proceeds
thereof) if the Indiana Returned Facility Note continues to be paid in
installments pursuant to the terms thereof (and not from such proceeds);

            (9)  "Maturity Date" means the earliest of (i) the Scheduled
Maturity Date, (ii) any LBO Transaction Date, or (iii) the effective date of any
acceleration pursuant to paragraph (9) of this Note;

            (10) "Note Rate" means 9% per annum;

            (11) "OPB" means, at any relevant time, the then unpaid principal
balance of the obligation evidenced by this Note;

            (12) "Plan" means the Debtors' First Amended Joint Plan of
Reorganization dated October 15, 1998, as further amended pursuant to amendments
dated November 17, 1998, November 20, 1998, and December 8, 1998, and the order
confirming that plan, in Chapter 11 Case No. B-98-06583-PHX GBN et seq., in the
United States Bankruptcy Court for the District of Arizona;


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            (13) "Quarter" means each of the four periods of three consecutive
calendar months which together constitute each calendar year;

            (14) "Scheduled Maturity Date" means January 31, 2003;

            (15) "Senior Notes" has the meaning provided in the Plan; and

            (16) "Subsidiary" means, at any relevant time, any corporation,
partnership, limited liability company or other business entity which Maker then
has the direct or indirect power to manage or control as a result of equity
interests owned or controlled by Maker.

         3. Interest Accrual and Computation. Subject to the following sentence,
interest will accrue on the OPB from the Effective Date until paid at the
Effective Rate. All past due interest, except for interest on interest accrued
after Scheduled Maturity, will accrue interest at the Default Rate until paid.
All interest will be computed on the basis of actual days elapsed and a 360-day
year of twelve 30-day months.

         4. Payment of Interest. Subject to paragraphs (5) and (6) of this Note,
all interest accrued on the OPB during each Quarter shall be paid by Maker to
Holder on or before the first day of the immediately succeeding Quarter.

         5. Final Maturity. Subject to paragraph (6), the OPB and all then
accrued and unpaid interest shall be paid by Maker to Holder on the Maturity
Date.

         6. Business Days. If any payment is due pursuant to paragraph (4) or
(5) on a date which is not a Business Day, the payment may be made on the next
succeeding Business Day and shall then be deemed timely made for all purposes.

         7. Prepayments. Maker may prepay all or any portion of the indebtedness
evidenced by this Note at any time without penalty. Maker shall identify each
optional prepayment of principal as such by notice to Holder at the time of
payment.

         8. Application of Payments. Except for optional prepayments of
principal pursuant to paragraph (7) of this Note, all payments on the obligation
evidenced by this Note shall be applied: (a) first, to any fees and/or costs
then payable by Maker to Holder pursuant to paragraph (10) of this Note; (b)
second, to accrued and unpaid interest; and (c) third, to the OPB.

         9. Acceleration. Subject to the following two sentences, upon the
occurrence of any Event of Default, Holder may declare the total then unpaid
obligation of Maker then evidenced by this Note to be immediately due and
payable in full, and such total obligation shall thereafter bear interest at the
Default Rate until paid. Holder shall not declare the obligation of Maker then
evidenced by this Note to be immediately due and payable prior to the Scheduled
Maturity Date without first giving Maker notice of such Event of Default and a
period of 15 days in which to cure such Event of Default. Notwithstanding any
conflicting provision of this Note, if


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an Event of Default described in clause (iv), (v), (vi) or (vii) of subparagraph
(2)(c) of this Note occurs the entire obligation of Maker then evidenced by this
Note will become immediately due and payable in full without notice or
opportunity to cure, and such total obligation shall thereafter bear interest at
the Default Rate until paid.

            10. Enforcement Costs. In event of any suit or other proceeding to
enforce any obligation of Maker under this Note, the prevailing party shall be
entitled to recover from the other party its reasonable attorneys' fees and
costs incurred therein, to be fixed in the sole discretion of the court.

            11. Interest Limit. All interest and other charges and reimbursable
fees and costs that Maker is or may become obligated to pay or reimburse in
connection with the obligation evidenced by this Note, and which constitute
"interest" within the meaning of Arizona Revised Statutes Sections 44-1201 et
seq., constitute items of interest in addition to the Effective Rate of
interest, which Maker hereby contracts in writing to pay. If fulfillment of any
provision of this Note would require Maker to pay any amount of interest in
excess of the maximum amount, if any, lawfully collectible under applicable law,
then the obligations of Maker to be fulfilled shall be automatically reduced to
the maximum amount lawfully collectible.

            12. Notices. Any notice pursuant to this Note must be in writing,
specifically reference this Note, and be given by United States certified mail,
postage prepaid and properly addressed, or by telecopy transmission, as follows:
(a) if to Maker, to (i) Maker at its address set forth above, or by telecopy at
602-481-6479, Attn: Treasurer, with a copy to (ii) Squire, Sanders & Dempsey
L.L.P., Two Renaissance Square, 40 North Central Avenue, Suite 2700, Phoenix,
Arizona 85004, Attn: Christopher D. Johnson, Esq. [telecopy 602-253-8129]; or
(b) if to Payee, to (i) Payee at its address set forth above, or by telecopy at
214-521-8846, Attn: Bruce H. Whitehead, with a copy to (ii) Ryley, Carlock &
Applewhite, P.A., 101 North First Avenue, Suite 2700, Phoenix, Arizona 85003,
Attn: James D. O'Neil, Esq. [telecopy 602-257-9582]. Either party may change any
of its or its counsel's addresses or telecopy numbers by at least five Business
Days' prior notice to the other party.


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            13. Miscellaneous. This Note is issued in and shall be governed by
and construed in accordance with the laws of the State of Arizona. This Note is
issued pursuant to the Plan, and reflects the Payee's portion of the BritWill
Acquisition Promissory Note pursuant to Article 6.2.2(b)(ii)(3) of the Plan.
This Note is unsecured. Maker waives presentment, dishonor, protest and demand,
diligence, notice of protest, demand and of dishonor, and any other notice
otherwise required to be given under law in connection with the delivery,
acceptance, performance, default, enforcement or collection of this Note, except
as is expressly provided in paragraph (9) of this Note. Time is of the essence
of this Note. No consent or waiver by any Holder with respect to any action or
failure to act which, without such consent or waiver, would constitute a breach
of any provision of this Note, shall be valid or binding unless in writing and
signed by both Maker and Holder.

                                    RAINTREE  HEALTHCARE CORPORATION,
                                    a Delaware corporation



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