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                                                                   EXHIBIT 10.15

                                      NOTE


$350,000.00                                                       Menlo Park, CA

                                                                 January 9, 1998

        Thirty (30) days after demand, Richard C. Davis, M.D. ("Borrower")
promises to pay to the order of UroQuest Medical Corporation, a Delaware
corporation (the "Company"), at 173 Constitution Drive, Menlo Park, California
94025, or at such other place as the holder of this note may designate, the
principal sum of Three Hundred Fifty Thousand Dollars ($350,000), together with
interest on the unpaid principal amount from the date hereof until paid at the
rate of five and six-tenths percent (5.60%) per annum, computed as if each year
consisted of three hundred sixty (360) days and each month consisted of thirty
(30) days, or such portion thereof as may be demanded; successive demands may be
made until the entire amount due hereunder has been paid.

        If any part of the principal hereof is not paid when due, such part of
the principal will bear interest from the due date at the maximum rate permitted
by law until the date of payment.

        The Borrower may at any time prepay all or any portion of the principal
owing hereunder.

        This Note is secured in part by a pledge of the Company's Common Stock
under the terms of a Security Agreement of even date herewith and is subject to
all the provisions thereof.

        The holder of this Note shall have full recourse against the Borrower,
and shall not be required to proceed against the collateral securing this Note
in the event of default.

        Demands hereunder shall be deemed to have been received by the Borrower
if delivered or telecopied to the address below on the date thereof, or three
(3) days after having been mailed postpaid in the United States mails, so
addressed. The Borrower may change the address for notices by written notice to
the holder of this note.

        If any provision of this note is held invalid or unenforceable, it shall
not affect the validity and enforceability of the other provisions of this note.

        If actions are taken to enforce this note, the Borrower agrees to pay
all costs of collection, including, but not limited to, reasonable attorney's
fees incurred by the holder hereof on account of such collection, whether or not
suit is filed hereon.

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        This note is executed and delivered in, and shall in all respects be
governed by and construed in accordance with, the laws of the State of
California, including all matters of construction, validity and performance.


                                        /s/ Richard C. Davis, M.D.
                                        ----------------------------------------
                                        Richard C. Davis, M.D.


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                               SECURITY AGREEMENT

        This Security Agreement is made as of January 9, 1998 between UroQuest
Medical Corporation, a Delaware corporation ("Pledgee"), and Richard C. Davis,
M.D. ("Pledgor").

                                    Recitals

        Pursuant to Pledgor's Note dated and given to Pledgee on the date hereof
(the "Note"), Pledgor has borrowed $350,000.00 from Pledgee and wishes to secure
repayment of the Note with shares of Pledgee's Common Stock (the "Shares").

        NOW, THEREFORE, it is agreed as follows:

        1. Creation and Description of Security Interest. In consideration of
the loan of $350,000.00 to Pledgor under the Note, Pledgor, pursuant to the
California Commercial Code, hereby pledges 350,000 Shares (herein sometimes
referred to as the "Collateral") represented by certificate number ______, duly
endorsed in blank or with executed stock powers, and herewith delivers said
certificate to the Secretary of Pledgee ("Pledgeholder"), who shall hold said
certificate subject to the terms and conditions of this Security Agreement.

        The pledged stock (together with an executed blank stock assignment for
use in transferring all or a portion of the Shares to Pledgee if, as and when
required pursuant to this Security Agreement) shall be held by the Pledgeholder
as security for the repayment of the Note, and any extensions or renewals
thereof, executed by Pledgor, and the Pledgeholder shall not encumber or dispose
of such Shares except in accordance with the provisions of this Security
Agreement.

        2. Pledgor's Representations and Covenants. To induce Pledgee to enter
into this Security Agreement, Pledgor represents and covenants to Pledgee, its
successors and assigns, as follows:

               a. Payment of Indebtedness. Pledgor will pay the principal sum of
the Note secured hereby, together with interest thereon, at the time and in the
manner provided in the Note.

               b. Encumbrances. The Shares are free of all other encumbrances,
defenses and liens, and Pledgor will not further encumber the Shares without the
prior written consent of Pledgee.

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               c. Margin Regulations. In the event that Pledgee's Common Stock
is now or later becomes margin-listed by the Federal Reserve Board and Pledgee
is classified as a "lender" within the meaning of the regulations under Part 207
of Title 12 of the Code of Federal Regulations ("Regulation G"), Pledgor agrees
to cooperate with Pledgee in making any amendments to the Note or providing any
additional collateral as may be necessary to comply with such regulations.

        3. Voting Rights. During the term of this pledge and so long as all
payments of principal and interest are made as they become due under the terms
of the Note, Pledgor shall have the right to vote all of the Shares pledged
hereunder.

        4. Stock Adjustments. In the event that during the term of the pledge
any stock dividend, reclassification, readjustment or other changes are declared
or made in the capital structure of Pledgee, all new, substituted and additional
shares or other securities issued by reason of any such change shall be
delivered to and held by the Pledgee under the terms of this Security Agreement
in the same manner as the Shares originally pledged hereunder. In the event of
substitution of such securities, Pledgor, Pledgee and Pledgeholder shall
cooperate and execute such documents as are reasonable so as to provide for the
substitution of such Collateral and, upon such substitution, references to
"Shares" in this Security Agreement shall include the substituted shares of
capital stock of Pledgor as a result thereof.

        5. Options and Rights. In the event that, during the term of this
pledge, subscription Options or other rights or options shall be issued in
connection with the pledged Shares, such rights, Options and options shall be
the property of Pledgor and, if exercised by Pledgor, all new stock or other
securities so acquired by Pledgor as it relates to the pledged Shares then held
by Pledgeholder shall be immediately delivered to Pledgeholder, to be held under
the terms of this Security Agreement in the same manner as the Shares pledged.

        6. Default. Pledgor shall be deemed to be in default of the Note and of
this Security Agreement in the event:

               a. Payment of principal or interest on the Note shall be
delinquent for a period of 10 days or more; or

               b. Pledgor fails to perform any of the covenants contained in
this Security Agreement for a period of 10 days after written notice thereof
from Pledgee.

        In the case of an event of Default, as set forth above, Pledgee shall
have the right to accelerate payment of the Note upon notice to Pledgor, and
Pledgee shall thereafter be entitled to pursue its remedies under the California
Commercial Code.


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         7. Release of Collateral. Subject to any applicable contrary rules
under Regulation G, there shall be released from this pledge a portion of the
pledged Shares held by Pledgeholder hereunder upon payments of the principal of
the Note. The number of the pledged Shares which shall be released shall be that
number of full Shares which bears the same proportion to the initial number of
Shares pledged hereunder as the payment of principal bears to the initial full
principal amount of the Note.

         8. Withdrawal or Substitution of Collateral. Pledgor shall not sell,
withdraw, pledge, substitute or otherwise dispose of all or any part of the
Collateral without the prior written consent of Pledgee.

         9. Term. The within pledge of Shares shall continue until the payment
of all indebtedness secured hereby, at which time the remaining pledged stock
shall be promptly delivered to Pledgor, subject to the provisions for prior
release of a portion of the Collateral as provided in paragraph 7 above.

        10. Insolvency. Pledgor agrees that if a bankruptcy or insolvency
proceeding is instituted by or against it, or if a receiver is appointed for the
property of Pledgor, or if Pledgor makes an assignment for the benefit of
creditors, the entire amount unpaid on the Note shall become immediately due and
payable, and Pledgee may proceed as provided in the case of default.

        11. Pledgeholder Liability. In the absence of willful or gross
negligence, Pledgeholder shall not be liable to any party for any of his acts,
or omissions to act, as Pledgeholder.

        12. Invalidity of Particular Provisions. Pledgor and Pledgee agree that
the enforceability or invalidity of any provision or provisions of this Security
Agreement shall not render any other provision or provisions herein contained
unenforceable or invalid.

        13. Successors or Assigns. Pledgor and Pledgee agree that all of the
terms of this Security Agreement shall be binding on their respective successors
and assigns, and that the term "Pledgor" and the term "Pledgee" as used herein
shall be deemed to include, for all purposes, the respective designees,
successors, assigns, heirs, executors and administrators.

        14. Governing Law. This Security Agreement shall be interpreted and
governed under the laws of the State of California.


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        IN WITNESS WHEREOF, the parties hereto have executed this Agreement as
of the day and year first above written.

        "PLEDGOR"              By:             /s/ Richard C. Davis, M.D.
                                              ----------------------------------
                                              Richard C. Davis, M.D.

                               Address:       4870 Longwater Way
                                              ----------------------------------
                                              Tampa, FL  33615
                                              ----------------------------------


        "PLEDGEE"              UROQUEST MEDICAL CORP.
                               a Delaware corporation


                               By:     /s/ Jeffrey L. Kaiser
                                       -----------------------------------------
                               Title:  Chief Financial Officer


        "PLEDGEHOLDER"         /s/ Jeffrey L. Kaiser
                               -------------------------------------------------
                               Jeffrey Kaiser
                               Secretary of
                               UroQuest Medical Corp.


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