$56,000.00                                                    Dated May 19, 1998



                      AMENDED AND RESTATED PROMISSORY NOTE


The  undersigned  ("Maker")  executed a promissory  note dated May 19, 1997 (the
"Initial  Note"),  payable to Health Care Capital Corp,  now known as Sonus Corp
("Holder"). Holder has agreed to extend the maturity date of the Initial Note to
November 1, 1999.  The Initial Note shall  therefore be replaced in its entirety
by this Amended and Restated Promissory Note.

For value received,  the undersigned promises to pay to the order of Holder, the
principal  sum of  Fifty-Six  Thousand  and  no/100  Dollars  ($56,000.00)  with
interest thereon at ten percent (10%) per annum from May 19, 1997. Principal and
interest shall be payable in lawful money of the United States of America at 111
SW Fifth Avenue,  Suite 2390,  Portland,  Oregon 97204 or at such other place as
Holder may  designate in writing.  Principal  and interest  shall become due and
payable on November 1, 1999.

Maker agrees to pay all costs of collection  of any amounts due  hereunder  when
incurred, including, without limitation, attorney's fees and expenses, including
on any  appeal.  Such  costs  shall be added to the  balance  of  principal  and
interest then due.

Maker,  for himself and his successors and assigns,  hereby waives  presentment,
demand,  notice and protest and any defense by reason of  extension  of time for
payment or other  indulgences.  Failure of the Holder to assert any right herein
shall not be deemed to be a waiver hereof.

This Amended and Restated  Promissory Note is secured.  The Maker has executed a
Pledge  Agreement  dated May 19, 1997,  which  describes the  collateral and the
process for realization on the security in the event of a default hereunder.

This Amended and Restated Promissory Note shall be governed by and construed and
enforced in accordance with the laws of the State of Oregon.

                                    Maker:



                                    /s/ Gene K. Balzer, Ph.D.
                                    Gene K. Balzer, Ph.D., an individual
<PAGE>
                                PLEDGE AGREEMENT


DATE:                      May 19, 1997

PARTIES:                   HEALTHCARE CAPITAL CORP., an Alberta,    ("Lender")
                           Canada corporation

AND:                       GENE K. BALZER, Ph.D., an individual   ("Borrower")


RECITAL:

Contemporaneous  with this Agreement,  Borrower has exercised stock options from
Lender for Two Hundred  Thousand  (200,000) Shares of Common Stock of HEALTHCARE
CAPITAL CORP.,  an Alberta,  Canada  corporation  and issued Lender a promissory
note of even date herewith in the amount of $56,000.00  (the "Note").  To secure
all amounts due now or later from  Borrower to Lender  under the Note,  Borrower
hereby  pledges  to  Lender  a  security  interest  in the  following  described
property:

         One Hundred Thousand  (100,000) shares of the common stock of Lender as
         evidenced by stock  certificate no. , endorsed in the blank by Borrower
         (the "Shares").

AGREEMENT:

SECTION 1.  POSSESSION

Lender shall retain possession of the Shares until all amounts due from Borrower
to Lender are paid in full.

SECTION 2.  DEFAULT

Borrower  shall be in default under this Agreement if Borrower fails to make any
payment to Lender when due, or if borrower  violates any terms of this Agreement
or the Note.  Upon default,  Lender shall have all the rights of a secured party
under the Oregon Uniform Commercial Code,  including,  subject to Section 3, the
right to sell the Shares at either a private or public sale.

SECTION 3.  SECURITIES LAWS

Borrower  acknowledges  that the sale of the  Shares by Lender may be subject to
certain  securities  laws,  and Borrower  agrees that Lender may take any action
necessary  in order to comply with such laws,  including  any and all  necessary
restrictions with respect to the time, place, manner and conditions of sale.

IN WITNESS  WHEREOF,  Borrower has executed this Pledge Agreement on the day and
year first written above.

                           Borrower:



                           /s/ Gene K. Balzer, Ph.D.
                           Gene K. Balzer, Ph.D.
                           an individual