<PAGE>   1

                                                                   EXHIBIT 10.26

                              LEASE AND AMENDMENTS


DATED:   APRIL 20, 1992

BETWEEN: PACIFIC REALTY ASSOCIATES, L.P.
         A DELAWARE LIMITED PARTNERSHIP                           LANDLORD

AND:     PI (MEDICAL)
         AN OREGON CORPORATION                                    TENANT


        Tenant wishes to lease from Landlord the following described property,
hereinafter referred to as "the Premises":

        Approximately 5,000 square feet of office space located in Building B,
PacTrust Business Center, 16125 S.W. 72nd Avenue, Portland, Oregon 97224 and as
further described on the attached Exhibits A, B and C.

        If the Premises consist of a portion but not all of a building, the
building housing the Premises is hereinafter referred to as "the Building."

        Landlord leases the Premises to Tenant for a term of 38 months
commencing May 1, 1992 and continuing through June 30, 1995. No base rent shall
be due for the first two months of the lease term, but Tenant shall be obligated
to pay for all other charges, taxes and expenses to be paid to Landlord
specified in paragraphs 3 and 4 of this lease. Base rent shall be according to
the following schedule:

<TABLE>
<CAPTION>
                                                   Base Rent          8/12/92
        Period                                     Per Month         Amendment
        ------                                     ---------         ---------
        <S>                                        <C>               <C>
        May 1, 1992 through June 30, 1992             $ 0.00
        July 1, 1992 through June 30, 1993         $2,800.00         $3,159.00
        July 1, 1993 through June 30, 1994         $3,000.00         $3,359.00
        July 1, 1994 through June 30, 1995         $3,500.00         $3,859.00
</TABLE>

Rent for the third month of the lease term has been paid upon execution of this
lease. All rent, including base rent together with the charges, taxes and
expenses to be paid to Landlord specified in paragraphs 3 and 4 of this lease,
is payable in advance on the first day of each calendar month. If Landlord
consents, Tenant may occupy the Premises prior to such commencement date upon
payment of rent on a prorated basis and compliance with all terms of this lease.

        Delivery of possession shall occur when the Premises are occupied by
Tenant or are ready to be occupied by Tenant with all work to be performed by
Landlord substantially completed. No notice shall be required from Landlord if
the Premises are ready on the date



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set for commencement of the term or on the first business day thereafter. If
Landlord is unable to deliver possession of the Premises to Tenant because of
strikes, acts of God, or any other cause beyond Landlord's control, then Tenant
may take possession when Landlord notifies Tenant that the Premises are ready
for possession, and the term of this lease shall commence on the first day of
the first month following such date and continue for the specified number of
months thereafter, notwithstanding the commencement and termination dates stated
above. Tenant shall owe no rent until the Premises are ready for possession.
Landlord shall have no liability for such delays in delivery of possession, and
neither party shall have the right to terminate except that Landlord may cancel
this lease without liability if permission to construct, use, or furnish
necessary utilities to the Premises is denied or revoked by any governmental
agency or public utility with such authority.

        This lease is subject to the following additional terms to which the
parties agree:

        1. USE OF THE PREMISES.

                (a) Tenant shall use the Premises only for the purpose of
conducting the following business:

                Development of processes and products for use invasively (in
vivo) in medical applications and related uses. If such use is prevented by any
law or governmental regulation, Tenant may use the Premises for other reasonable
uses.

                (b) In connection with its use, Tenant shall at its expense
comply with all applicable laws, ordinances, and regulations of any public
authority, including those requiring alteration of the Premises because of
Tenant's specific use; shall create no nuisance nor allow any objectionable
liquid, odor, or noise to be emitted from the Premises; shall store no gasoline
or other highly combustible materials on the Premises which would violate any
applicable fire code or regulation nor conduct any operation that will increase
Landlord's fire insurance rates for the Premises; and shall not overload the
floors or electrical circuits of the Premises. Landlord shall have the right to
approve the installation of any power-driven machinery by Tenant and may select
a qualified electrician whose opinion will control regarding electrical circuits
and a qualified engineer or architect whose opinion will control regarding floor
loads. Allowable ground floor load shall be 300 pounds per square foot.

                (c) Tenant may erect a sign stating its name, business, and
product after first securing Landlord's written approval of the size, color,
design, wording, and location, and all necessary governmental approvals. No
signs shall be painted on the Building or exceed the height of the Building. All
signs installed by Tenant shall be removed upon termination of this lease with
the sign location restored to its former state.

                (d) Tenant shall make no alterations, additions, or improvements
to the Premises or change the color of the exterior without Landlord's prior
written consent and



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without a valid building permit issued by the appropriate governmental agency.
Upon termination of this lease, any such alternations, additions, or
improvements (including without limitation all electrical, lighting, plumbing,
heating and air-conditioning equipment, doors, windows, partitions, drapery,
carpeting, shelving, counters, and physically attached fixtures) shall at once
become part of the realty and belong to Landlord unless the terms of the
applicable consent provide otherwise, or Landlord requests that part or all of
the additions, alterations, or improvements be removed. In such case, Tenant
shall at its sole cost and expense promptly remove the specified additions,
alterations, or improvements and repair and restore the Premises to its original
condition.

        2. SECURITY DEPOSIT.

                Tenant has deposited with Landlord the sum of $3,500.00,
hereinafter referred to as "the Security Deposit," to secure the faithful
performance by Tenant of each term, covenant, and condition of this lease. If
Tenant shall at any time fail to make any payment or fail to keep or perform any
term, covenant, and condition on its part to be made or performed or kept under
this lease, Landlord may, but shall not be obligated to and without waiving or
releasing Tenant from any obligation under this lease, use, apply or retain the
whole or any part of the Security Deposit (i) to the extent of any sum due to
Landlord; or (ii) to make any required payment on Tenant's behalf; or (iii) to
compensate Landlord for any loss, damage, attorneys' fees, or expense sustained
by Landlord due to Tenant's default. In such event, Tenant shall, within 5 days
of written demand by Landlord, remit to Landlord sufficient funds to restore the
Security Deposit to its original sum; Tenant's failure to do so shall be a
material breach of this lease. Landlord shall not be required to keep the
Security Deposit separate from its general funds, and Tenant shall not be
entitled to interest on such deposit. Should Tenant comply with all of the
terms, covenants, and conditions of this lease and at the end of the term of
this lease leave the Premises in the condition required by this lease, then the
Security Deposit, less any sums owing to Landlord, shall be returned to Tenant
(or, at Landlord's option, to the last assignee of Tenant's interests hereunder)
within 30 days after the termination of this lease and vacancy of the Premises
by Tenant.

        3. UTILITY CHARGES; MAINTENANCE.

                (a) Tenant shall pay when due all charges for electricity,
natural gas, water, garbage collection, janitorial service, sewer, and all other
utilities of any kind furnished to the Premises during the lease term. If
charges are not separately metered or stated, Landlord shall apportion the
utility charges on an equitable basis. Landlord shall have no liability
resulting from any interruption of utility services caused by fire or other
casualty, strike, riot, vandalism, the making of necessary repairs or
improvements, or any other cause beyond Landlord's reasonable control. Tenant
shall control the temperature in the Premises to prevent freezing of any
sprinkler system.

                (b) Landlord shall repair and maintain the roof, gutters,
downspouts, exterior walls, building structure, foundation, exterior paved
areas, and curbs of the Premises in good condition. Except for such obligations
of Landlord, Tenant shall keep the Premises



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neatly maintained and in good order and repair. Tenant's responsibility shall
include maintenance and repair of the electrical system, plumbing,
air-conditioning and heating systems, overhead and personnel doors, and the
replacement of all broken or cracked glass with glass of the same quality.
Tenant shall refrain from any discharge that will damage the septic tank or
sewers serving the Premises.

                (c) If the Premises have a separate entrance, Tenant shall keep
the sidewalks abutting the Premises or the separate entrance free and clear of
snow, ice, debris, and obstructions of every kind.

        4. TAXES, ASSESSMENTS, AND OPERATING EXPENSES.

                (a) In conjunction with monthly rent payments, Tenant shall each
month pay a sum representing Tenant's proportionate share of real property taxes
and operating expenses for the Premises. Such amount shall annually be estimated
by Landlord in good faith to reflect actual or anticipated costs. Upon
termination of this lease or at periodic intervals during the term hereof,
Landlord shall compute its actual costs for such expenses during such period.
Any overpayment by Tenant shall be credited to Tenant, and any deficiency shall
be paid by Tenant within 15 days after receipt of Landlord's statement.
Landlord's records of expenses for taxes and operating expenses may be inspected
by Tenant at reasonable times and intervals.

                (b) Tenant's proportionate share of real property taxes shall
mean that percentage of the total assessment affecting the Premises which is the
same as the percentage which the rentable area of the Premises bears to the
total rentable area of all buildings covered by the tax statement. Tenant's
proportionate share of operating expenses for the Building shall be computed by
dividing the rentable area of the Premises by the total rentable area of the
Building. If in Landlord's reasonable judgment either of these methods of
allocation results in an inappropriate allocation to Tenant, Landlord shall
select some other reasonable method of determining Tenant's proportionate share.

                (c) Real property taxes charged to Tenant hereunder shall
include all general real property taxes assessed against the Premises or payable
during the lease term, installment payments on Bancrofted special assessments,
and any rent tax, tax on Landlord's interest under this lease, or any tax in
lieu of the foregoing, whether or not any such tax is now in effect. Tenant
shall not, however, be obligated to pay any tax based upon Landlord's net
income.

                (d) Operating expenses charged to Tenant hereunder shall include
all usual and necessary costs of operating and maintaining the Premises,
Building, and any surrounding common areas including, but not limited to, the
cost of all utilities or services not paid directly by Tenant, property
insurance, property management, maintenance and repair of landscaping, parking
areas, and any other common facilities. Operating expenses shall not include
roof replacement or correction of structural deficiencies of the Building.



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<PAGE>   5

        5. PARKING AND STORAGE AREAS.

                (a) Tenant, its employees, and customers shall have the
exclusive right to use any private parking spaces immediately adjacent to the
Premises. Tenant shall control the use of such parking spaces so that there will
be no unreasonable interference with the normal traffic flow, and shall permit
no parking on any landscaped or unpaved surface. Under no circumstances shall
trucks serving the Premises be permitted to block streets.

                (b) Tenant shall not store any materials, supplies, or equipment
outside in any unapproved or unscreened area. If Tenant erects any visual
barriers for storage areas, Landlord shall have the right to approve the design
and location. Trash and garbage receptacles shall be kept covered at all times.

        6. TENANT'S INDEMNIFICATION; LIABILITY INSURANCE.

                (a) Tenant shall not allow any liens to attach to the Premises
as a result of its activities. Tenant shall indemnify and defend Landlord from
any claim, liability, damage, or loss arising out of any activity on the
Premises by Tenant, its agents, or invitees or resulting from Tenant's failure
to comply with any term of this lease.

                (b) Tenant shall carry general liability insurance on an
occurrence basis with combined single limits of not less than $1,000,000. Such
insurance shall be provided by an insurance carrier reasonably acceptable to
Landlord and shall be evidenced by a certificate delivered to Landlord stating
that the coverage will not be canceled or materially altered without 10 days'
advance written notice to Landlord. Landlord shall be named as an additional
insured on such policy.

        7. PROPERTY DAMAGE; SUBROGATION WAIVER.

                (a) If fire or other casualty causes damage to the Building or
the Premises in an amount exceeding 30 percent of the full
construction-replacement cost of the Building or Premises, respectively,
Landlord may elect to terminate this lease as of the date of the damage by
notice in writing to Tenant within 30 days after such date. Otherwise, Landlord
shall promptly repair the damage and restore the Premises to their former
condition as soon as practicable. Rent shall be reduced during the period to the
extent the Premises are not reasonably usable for the use permitted by this
lease because of such damage and required repairs.

                (b) Landlord shall be responsible for insuring the Building, and
Tenant shall be responsible for insuring its personal property and trade
fixtures located on the Premises.

                (c) Neither party shall be liable to the other for any loss or
damage caused by water damage, sprinkler leakage, or any of the risks covered by
a standard fire insurance policy with extended coverage and sprinkler leakage
endorsements, and there shall be no subrogated claim by one party's insurance
carrier against the other party arising out of any such loss.



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<PAGE>   6

        8. CONDEMNATION.

                If a condemning party takes the entire Premises or a portion
sufficient to render the remainder unsuitable for Tenant's use, then either
party may elect to terminate this lease effective on the date that little passes
to the condemning authority. Otherwise, Landlord shall proceed as soon as
practicable to restore the remaining Premises to a condition comparable to that
existing at the time of the taking. Rent shall be abated during the period of
restoration to the extent the Premises are not reasonably usable by Tenant, and
rent shall be reduced for the remainder of the term in an amount equal to the
reduction in rental value of the Premises caused by the taking. All condemnation
proceeds shall belong to Landlord.

        9. ASSIGNMENT AND SUBLETTING.

                (a) Tenant shall not assign its interest under this lease nor
sublet the Premises without first obtaining Landlord's consent in writing. This
provision shall apply to all transfers by operation of law or through mergers
and changes in control of Tenant. No assignment shall relieve Tenant of its
obligation to pay rent or perform other obligations required by this lease and
no one assignment or subletting shall be a consent to any further assignment or
subletting.

                (b) Subject to the above limitations on transfers of Tenant's
interest, this lease shall bind and inure to the benefit of the parties, their
respective heirs, successors, and assigns.

        10. DEFAULT.

                Any of the following shall constitute a default by Tenant under
this lease:

                (a) Tenant's failure to pay rent or any other charge under this
lease within 10 days after it is due, or failure to comply with any other term
or condition within 30 days following written notice from Landlord specifying
the noncompliance. If such noncompliance cannot be cured within the 30-day
period, this provision shall be satisfied if Tenant commences correction within
such period and thereafter proceeds in good faith and with reasonable diligence
to effect compliance as soon as possible.

                (b) Tenant's insolvency; assignment for the benefit of its
credits; Tenant's voluntary petition in bankruptcy or adjudication as bankrupt,
or the appointment of a receiver for Tenant's properties.

        11. REMEDIES FOR DEFAULT.

                In case of default as described in paragraph 10 above, Landlord
shall have the right to the following remedies which are intended to be
cumulative and in addition to any other remedies provided under applicable law:



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                (a) Terminate this lease without relieving Tenant from its
obligation to pay damages.

                (b) Retake possession of the Premises by summary proceedings or
otherwise, in which case Tenant's liability to Landlord for damages shall
survive the tenancy. Landlord may, after such retaking of possession, relet the
Premises upon any reasonable terms. No such reletting shall be construed as an
acceptance of a surrender of Tenant's leasehold interest.

                (c) Recover damages caused by Tenant's default which shall
include reasonable attorneys' fees at trial and on any appeal therefrom.
Landlord may sue periodically to recover damages as they occur throughout the
lease term, and no action for accrued damages shall bar a later action for
damages subsequently accruing. Landlord may elect in any one action to recover
accrued damages plus damages attributable to the remaining term of the lease
equal to the difference between the rent under this lease and the reasonable
rental value of the Premises for the remainder of the term, discounted to the
time of judgment at the rate of 6 percent per annum.

                (d) Make any payment or perform any obligation required of
Tenant so as to cure Tenant's default, in which case Landlord shall be entitled
to recover all amounts so expended from Tenant, plus interest at the rate of 10
percent per annum from the date of the expenditure.

        12. SURRENDER OR TERMINATION.

                (a) On expiration or early termination of this lease, Tenant
shall deliver all keys to Landlord, have final utility readings made on the date
of move out, and surrender the Premises clean and free of debris inside and out,
with all mechanical, electrical, and plumbing systems in good operating
condition, all signing removed and defacement corrected, and all repairs called
for under this lease completed. The Premises shall be delivered in the same
condition as at the commencement of the term, subject only to depreciation and
wear from ordinary use. Tenant shall remove all of its furnishings and trade
fixtures that remain its property and restore all damage resulting from such
removal. Failure to remove said property shall be an abandonment of same, and
Landlord may dispose of it in any manner without liability.

                (b) If Tenant fails to vacate the Premises when required,
Landlord may elect either to treat Tenant as a tenant from month to month,
subject to all provisions of this lease except the provision for term, or to
eject Tenant from the Premises and recover damages caused by wrongful holdover.

        13. LANDLORD'S LIABILITY.

                (a) Landlord warrants that so long as Tenant complies with all
terms of this lease it shall be entitled to peaceable and undisturbed possession
of the Premises free from any eviction or disturbance by Landlord or persons
claiming through Landlord.



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                (b) All persons dealing with Pacific Realty Associates, L.P.
("Partnership") must look solely to the property and assets of Partnership for
the payment of any claim against Partnership or for the performance of any
obligation of Partnership as neither the general partner, limited partners,
employees, nor agents of Partnership assume any personal liability for
obligations entered into on behalf of Partnership (or its predecessors in
interest) and their respective properties shall not be subject to the claims of
any person in respect of any such liability or obligation. As used herein, the
words "property and assets of partnership" exclude any rights of Partnership for
the payment of capital contributions or other obligations to it by the general
partner or any limited partner in such capacity.

        14. MORTGAGE OR SALE BY LANDLORD; ESTOPPEL CERTIFICATES.

                (a) This lease is and shall be prior to any mortgage or deed of
trust ("Encumbrance") recorded after the date of this lease and affecting the
Building and the land upon which the Building is located. However, if any lender
holding an Encumbrance secured by the Building and the land underlying the
Building requires that this lease be subordinate to the Encumbrance, then Tenant
agrees that this lease shall be subordinate to the Encumbrance if the holder
thereof agrees in writing with Tenant that so long as Tenant performs its
obligations under this lease no foreclosure, deed given in lieu of the
foreclosure, or sale pursuant to the terms of the Encumbrance, or other steps or
procedures taken under the Encumbrance shall affect Tenant's rights under this
lease. If the foregoing condition is met, Tenant shall execute the written
agreement and any other documents required by the holder of the Encumbrance to
accomplish the purposes of this paragraph.

                (b) If the Building is sold as a result of foreclosure of any
Encumbrance thereon or otherwise transferred by Landlord or any successor,
Tenant shall attorn to the purchaser or transferee, and the transferor shall
have no further liability hereunder.

                (c) Either party shall within 20 days after notice from the
other execute and deliver to the other party a certificate stating whether or
not this lease has been modified and is in full force and effect and specifying
any modifications or alleged breaches by the other party. The certificate shall
also state the amount of monthly base rent, the dates to which rent has been
paid in advance, and the amount of any security deposit or prepaid rent. Failure
to deliver the certificate within the specified time shall be conclusive upon
the party to whom the certificate was requested that the lease is in full force
and effect and has not been modified except as may be represented by the party
requesting the certificate.

        15. DISPUTES - ATTORNEYS' FEES.

                In the event of any litigation arising out of this lease, the
prevailing party shall be entitled to recover from the other party, in addition
to all other relief provided by law or judgement, its reasonable costs and
attorneys' fees incurred both at and in preparation for trial and any appeal or
review, such amount to be as determined by the court(s) before which the matter
is heard. Disputes between the parties which are to be litigated shall be tried
before a judge without a jury.



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        16. SEVERABILITY.

                If any provision of this lease is held to be invalid,
unenforceable or illegal the remaining provisions shall not be affected and
shall be enforced to the fullest extent permitted by law.

        17. INTEREST AND LATE CHARGES.

                Rent not paid within 10 days of when due shall bear interest
from the date due until paid at the rate of 10 percent per annum. Landlord may
at its option impose a late charge of $.05 for each $1.00 of rent for rent
payments made more than 10 days late in addition to interest and other remedies
available for default.

        18. GENERAL PROVISIONS.

                (a) Waiver by either party of strict performance of any
provision of this lease shall not be a waiver of nor prejudice the party's right
otherwise to require performance of the same provision or any other provision.

                (b) Subject to the limitations on transfer of Tenant's interest,
this lease shall bind and inure to the benefit of the parties, their respective
heirs, successors, and assigns.

                (c) Landlord shall have the right to enter upon the Premises at
any time to determine Tenant's compliance with this lease, to make necessary
repairs to the Building or the Premises, or to show the Premises do any
prospective tenant or purchasers. During the last two months of the term,
Landlord may place and maintain upon the Premises notices for leasing or sale of
the Premises.

                (d) If this lease commences or terminates at a time other than
the beginning or end of one of the specified rental periods, then the rent
(including Tenant's share of real property taxes, if any) shall be prorated as
of such date, and in the event of termination for reasons other than default all
prepaid rent shall be refunded to Tenant or paid on its account.

                (e) Tenant shall within 10 days following Landlord's written
request deliver to Landlord a written statement specifying the dates to which
the rent and other charges have been paid, whether the lease is unmodified and
in full force and effect, and any other matters that may reasonably be requested
by Landlord.

                (f) Notices between the parties relating to this lease shall be
in writing, effective when delivered, or if mailed, effective on the second day
following mailing, postage prepaid, to the address for the party stated in this
lease or to such other address as either party may specify by notice to the
other. Rent shall be payable to Landlord at the same address and in the same
manner.



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        19. REPAYMENT OF FREE RENT.

                This lease provides for a period of "free" rent (hereinafter
referred to as "the Abated Rent"). Tenant shall be credited with having paid all
of the Abated Rent on the expiration of the lease term only if Tenant has fully,
faithfully, and punctually performed all of Tenant's obligations hereunder,
including the payment of all rent (other than the Abated Rent) and all other
monetary obligations and the surrender of the Property in the physical condition
required by this lease. Tenant acknowledges that Tenant's right to receive
credit for the Abated Rent is absolutely conditioned upon Tenant's full,
faithful and punctual performance of its obligations under this lease. The
Abated Rent shall immediately become due and payable in full and this lease
shall be enforced as if there were no such rent abatement or other rent
concessions, in the event of default by Tenant under this lease and such default
is not cured within any applicable grace period.


        20. OPTION TO RENEW.

        If not then in default, Tenant shall have the option to renew this lease
for an additional 13 months immediately following expiration of the initial
lease term by giving Landlord 120 days' advance written notice of its intent to
extend. All provisions of this lease shall apply during the extended term, with
base rent for the renewal period remaining at $3,500.00 per month. No base rent
shall be due for the first month of the renewal period, but Tenant shall be
obligated to pay for all other charges, taxes and expenses to be paid to
Landlord as specified in paragraphs 3 and 4 of this lease.

        21. OPTION TO RELOCATE.

                If during the term of this lease Tenant notifies Landlord that
it is desirous of leasing additional square footage in an alternative space,
Landlord shall, providing Tenant is not then in default, use its best efforts to
relocate Tenant to an alternate location of at least 7.500 square feet within
one of its properties which is mutually acceptable to both parties.


        22. TENANT IMPROVEMENTS.

                Tenant Improvements within the Premises shall be constructed
generally as shown on the attached Exhibits C and D. Tenant improvement costs
shall be divided into the following categories:


                (a) Part A: Tenant improvements to be constructed at Landlord's
expense.

                (b) Part B: Tenant improvements to be constructed at Tenant's
expense.

        Part B tenant improvement costs shall be amortized over the 36 months of
this lease term during which base rent is to be paid. Such amount shall be
amortized at a rate of 12



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<PAGE>   11

percent per annum and the resulting monthly rent will be reflected in a Lease
Summary Agreement, which shall be executed by the parties prior to June 1, 1992.

        23. ENVIRONMENTAL.

                (a) Definitions. The term "Environmental Law" shall mean any
federal, state or local statute, regulation or ordinance or any judicial or
other governmental order pertaining to the protection of health, safety or the
environment. The term "Hazardous Substance" shall mean any hazardous, toxic,
infectious or radioactive substance, waste and material as defined or listed by
any Environmental Law and shall include, without limitation, petroleum oil and
its fractions.

                (b) Use of Hazardous Substances. Tenant shall not cause or
permit any Hazardous Substance to be spilled, leaked, disposed of or otherwise
released on or under the Premises. Tenant may use and sell on the Premises only
those Hazardous Substances typically used and sold in the prudent and safe
operation of the business permitted by Section 1. Tenant may store such
Hazardous Substances on the Premises, but only in quantities necessary to
satisfy Tenant's reasonably anticipated needs. Tenant shall comply with all
Environmental Laws and exercise the highest degree of care in the use, handling
and storage of Hazardous Substances and shall take all practicable measures to
minimize the quantity and toxicity of Hazardous Substances used, handled or
stored on the Premises.

                (c) Notices. Tenant shall immediately notify Landlord upon
receiving notice of the following: (a) any spill, leak, disposal or other
release of a Hazardous Substance on, under or adjacent to the Premises; (b) any
notice or communication from a governmental agency or any other parson rotating
to any Hazardous Substance on, under or adjacent to the Promises, or (c) any
violation of any Environmental Law with respect to the Premises or Tenant's
activities on or in connection with the Premises.

                (d) Spills and Releases. In the event Tenant becomes aware of a
spill, leak, disposal or other release of a Hazardous Substance caused by Tenant
on or under the Premises, or the suspicion or threat of the same, Tenant shall
(a) immediately undertake all emergency response necessary to contain, cleanup
and remove the released Hazardous Substance, (b) promptly undertake all
investigatory, remedial, removal and other response action necessary to ensure
that any Hazardous Substance contamination is eliminated to Landlord's
satisfaction, and (c) provide Landlord copies of all correspondence with any
governmental agency regarding the release (or threatened or suspected release)
or the response action, a detailed report documenting all such response action,
and a certification that any contamination has been eliminated to the degree
required by such authorities. All such response action shall be performed, all
such reports shall be prepared and all such certifications shall be made by an
environmental consultant reasonably acceptable to Landlord. This section 23(d)
shall not apply to any release caused by Landlord, other tenants of Landlord,
previous tenants of the Premises, their respective agents or contractors, or any
person other than Tenant or its respective agents or contractors.



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                (e) Investigations. Landlord reserves its right to inspect the
Tenant's use of Hazardous Substances on the Premises at any time upon reasonable
notice to Tenant. Tenant shall provide Landlord reasonable access to all records
relating to the management, use, storage or other handling of Hazardous
Substances on the Premises. If Landlord at any time during the term of this
Lease has reason to believe that Tenant is not complying with any of the
requirements of this Section 23, Landlord may require Tenant to furnish to
landlord, at Tenant's sole expense, an environmental audit with respect to the
matters Landlord reasonably believes to be out of compliance. Such environmental
audit shall be conducted by an environmental consultant acceptable to Landlord.

                (f) Condition Upon Termination.

                        (i) Upon termination expiration of this Lease for any
reason, Tenant shall remove all Hazardous Substances introduced by Tenant from
the Premises and, at Landlord's request, shall properly remove in compliance
with all applicable laws all tank systems and other facilities installed by
Tenant and used for the storage or handling of Hazardous Substances and restore
the affected areas by repairing any damage caused by the installation or removal
of the facilities. Following such removal, Tenant shall certify in writing to
Landlord that all such removal is complete. If any Hazardous Substances have
been released on or under the Premises during the term of this Lease, Tenant
shall cause all Hazardous Substances contamination to be eliminated to
Landlord's reasonable satisfaction and shall provide Landlord a certification
from an environmental consultant reasonably acceptable to Landlord that all
Hazardous Substances contamination on the Premises has been so eliminated.

                        (ii) Until such time as Tenant has fulfilled all the
requirements of subsection (i) above, Landlord may regard Tenant as a hold-over
tenant at will, and all rents under this Lease shall continue, provided,
however, that the continuation of this Lease shall not relieve Tenant of its
obligations under subsection (i).

                (g) Assignment and Subletting. Notwithstanding the provisions of
Section 9, it shall not be unreasonable for Landlord to withhold its consent to
any assignment, sublease or other transfer of the Tenant's interest in this
Lease if a proposed transferee's anticipated use of the premises involves the
generation, storage, use, sale, treatment, release or disposal of any Hazardous
Substance.

                (h) Indemnity.

                        (i) By Tenant. Tenant shall indemnify, defend and hold
harmless Landlord, its employees and agents, any persons holding a security
interest in the Premises, and the respective successors and assigns of each of
them from and against any and all claims, demands, liabilities, damages, fines,
losses, costs (including without limitation the cost of any investigation,
remedial, removal or other response action required by Environmental Law) and
expenses (including without limitation attorneys' fees end expert fees in
connection with any trial, appeal, petition for review or administrative
proceeding) arising out of or in any way



                                       12
<PAGE>   13

relating to the actual or alleged use, treatment, storage, generation,
transport, release, leak, spill, disposal or other handling of Hazardous
Substances on the Premises by Tenant or any of its contractors or agents,
employees or invitees. Tenant's obligations under this section shall survive the
expiration or termination of this Lease for any reason. Landlord's rights under
this section are in addition to and not in lieu of any other rights or remedies
to which Landlord may be entitled under this Agreement or otherwise.

                        (ii) By Landlord. Landlord shall indemnify, defend and
hold harmless Tenant and its employees and agents and the respective successors
and assigns of each of them from and against any and all claims, demands,
liabilities, damages, fines, losses, costs (including without limitation the
cost of any investigation, remedial, removal or other response action required
by Environmental Law) and expenses (including without limitation attorneys' fees
and expert fees in connection with any trial, appeal, petition for review or
administrative proceeding) arising out of or in any way relating to the actual
or alleged use, treatment, storage, generation, transport, release, leak, spill,
disposal or other handling of Hazardous Substances on the Premises by Landlord,
other tenants of Landlord, previous tenants of the Premises, their respective
agents or contractors, employees or invitees. Landlord's obligations under this
section shall survive the expiration or termination of this Lease for any
reason. Tenant's rights under this section are in addition to and not in lieu of
any other rights or remedies to which Tenant may be entitled under this
Agreement or otherwise.

        IN WITNESS WHEREOF, the duly authorized representatives of the parties
have executed this lease as of the day and year first written above.

PACIFIC REALTY ASSOCIATES, LP.         PI (MEDICAL)

BY  PACTRUST REALTY, INC.,
    ITS GENERAL PARTNER


    By  /s/ DAVID G. HICKS             By:  /s/ R.A. MURIE
      ----------------------------        --------------------------------------
        David G. Hicks                 Name   R.A. MURIE
        Vice President                     -------------------------------------
                                       Title  VP and Gen. Mgr.
                                            ------------------------------------

                                       By
                                         ---------------------------------------
                                       Name
                                           -------------------------------------
                                       Title
                                            ------------------------------------

ADDRESS FOR NOTICES/RENT PAYMENTS      ADDRESS FOR LEGAL NOTICES TO TENANT:
TO LANDLORD:
15115 S.W. Sequoia Parkway,
Suite 200                              -----------------------------------------
Portland, Oregon  97224
                                       -----------------------------------------

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



                                       13
<PAGE>   14

                                       ADDRESS FOR INVOICES TO TENANT:

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

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

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



                                       14
<PAGE>   15

                                 LEASE AMENDMENT

DATED:    AUGUST 12, 1992

BETWEEN:  PACIFIC REALTY ASSOCIATES, L.P.,
          A DELAWARE LIMITED PARTNERSHIP                                LANDLORD

AND:      PI (MEDICAL)
          AN OREGON CORPORATION                                           TENANT

        By written lease dated April 20, 1992, Tenant leased from Landlord
approximately 5,000 square feet of office space located in Building B, PacTrust
Business Center, 16125 S.W. 72nd Avenue, Portland, Oregon 97224 (hereinafter
referred to as "the Premises"). Such document is hereinafter referred to as "the
Lease." The Lease expires June 30, 1995.

        Landlord has completed Part B tenant improvements set forth in paragraph
22 of the lease, and costs for such improvements shall be amortized over the
remaining term of the Lease.

        NOW, THEREFORE, the parties agree as follows:

        1. Costs for Part B tenant improvements total $10,297.00.

        2. Commencing September 1, 1992 and continuing through June 30, 1995,
base rent shall increase by $359.00 per month according to the following
schedule:

<TABLE>
<CAPTION>
                                                                 Base Rent
         Period                                                  per Month
         ------                                                  ---------
         <S>                                                     <C>
         September 1, 1992 through June 30, 1993                 $3,159.00
         July 1, 1993 through June 30, 1994                      $3,359.00
         July 1, 1994 through June 30, 1995                      $3,859.00
</TABLE>


        3. Except as expressly modified hereby, all terms of the Lease shall
remain in full force and effect and shall continue through the existing term.



                                       1
<PAGE>   16

        IN WITNESS WHEREOF, the parties have executed this agreement as of the
date and year first written above.

PACIFIC REALTY ASSOCIATES, L.P.        PI (MEDICAL)

BY  PACTRUST REALTY, INC.,
    ITS GENERAL PARTNER


    By  /s/ DAVID G. HICKS             By    /s/ RICHARD MURIE
        ----------------------------         -----------------------------------
        David G. Hicks                 Name  Richard Murie
        Vice President                 Title Vice President



                                       2
<PAGE>   17

                                 LEASE AMENDMENT


DATED:   FEBRUARY 16, 1995

BETWEEN: PACIFIC REALTY ASSOCIATES, L.P.,
         A DELAWARE LIMITED PARTNERSHIP                                 LANDLORD

AND:     PI (MEDICAL)
         AN OREGON CORPORATION                                            TENANT

         By written lease dated April 20, 1992, Tenant leased from Landlord
approximately 5,000 square feet of office space located in Building B, PacTrust
Business Center, 16125 S.W. 72nd Avenue, Portland, Oregon 97224 (hereinafter
referred to as the "Premises"). By Lease Amendment dated August 12, 1992, the
lease was amended. By Lease Amendment dated February 16, 1995, the term of the
lease was extended. Such documents are hereinafter jointly referred to as the
"Lease." The Lease expires July 31, 1996.

                Tenant now wishes to extend the term of the Lease.

                NOW, THEREFORE, the parties agree as follows:

        1. The Lease shall be extended for an additional 12 months commencing
August 1, 1996 and continuing through July 31, 1997.

        2. Base rent shall increase from $3,500.00 to $3,750.00 per month
commencing August 1, 1996 and continuing through the extended term.

        3. Except as expressly modified hereby, all terms of the Lease shall
remain in full force and effect and shall continue through the extended term.

        IN WITNESS WHEREOF, the parties have executed this agreement as of the
date and year first written above.

PACIFIC REALTY ASSOCIATES, L.P.        PI (MEDICAL),
AN OREGON CORPORATION                  AN OREGON CORPORATION

BY  PACTRUST REALTY, INC.,
    ITS GENERAL PARTNER


    By  /s/ DAVID G. HICKS             By     /s/ RICHARD G. SASS
        ----------------------------          ----------------------------------
        David G. Hicks                 Name   Richard G. Sass
        Vice President                 Title


<PAGE>   18

                                 LEASE AMENDMENT


DATED:    APRIL 26, 1996

BETWEEN:  PACIFIC REALTY ASSOCIATES, L.P.,
          A DELAWARE LIMITED PARTNERSHIP                                LANDLORD

AND:      EVERGREEN ISLAND ENTERPRISES, INC.,
          AN OREGON CORPORATION                                           TENANT

        By written lease dated February 16, 1993, Tenant leased from Landlord
approximately 8,875 square feet of office and warehouse space located in
Building B, PacTrust Business Center, 16135 S.W. 72nd Avenue, Portland, Oregon
97224 (hereinafter referred to as the "Premises"). By Lease Amendment dated
February 16, 1995, the term of the lease was extended. Such documents are
hereinafter jointly referred to as the "Lease." The Lease expires July 31, 1990.

                Tenant now wishes to extend the term of the Lease.

                NOW, THEREFORE, the parties agree as follows:

        1. The Lease shall be extended for an additional 12 months commencing
August 1, 1996 and continuing through July 31, 1997.

        2. Base rent shall increase from $4,125.00 to $4,469.00 per month
commencing August 1, 1996 and continuing through the extended term.

        3. Except as expressly modified hereby, all terms of the Lease shall
remain in full force and effect and shall continue through the extended term.

        IN WITNESS WHEREOF, the parties have executed this agreement as of the
date and year first written above.

PACIFIC REALTY ASSOCIATES, L.P.,       EVERGREEN ISLAND ENTERPRISES, INC.
A DELAWARE LIMITED PARTNERSHIP         AN OREGON CORPORATION


BY PACTRUST REALTY, INC.,
 A DELAWARE CORPORATION,
    ITS GENERAL PARTNER


    By  /s/ DAVID G. HICKS             By     /s/ RICHARD G. SASS
        ----------------------------          ----------------------------------
        David G. Hicks                 Name   Richard G. Sass
        Vice President                 Title


<PAGE>   19

                                 LEASE AMENDMENT


DATED:    JULY 3, 1997

BETWEEN:  PACIFIC REALTY ASSOCIATES, L.P.,
          A DELAWARE LIMITED PARTNERSHIP                                LANDLORD

AND:      PI (MEDICAL),
          AN OREGON CORPORATION                                           TENANT


        By written lease dated April 20, 1992, Tenant leased from Landlord
approximately 5,000 square feet of office space located in Building B, PacTrust
Business Center, 16125 S.W. 72nd Avenue, Portland, Oregon 97224 (hereinafter
referred to as the "Premises"). By Lease Amendment dated August 12, 1992, the
Lease was amended. By Lease Amendments dated February 16, 1995 and April 26,
1996, the term of the Lease was extended. Such documents are hereinafter jointly
referred to as the "Lease." The Lease expires July 31, 1997.

        Tenant now wishes to extend the term of the Lease and to lease an
additional approximately 15,000 square feet of warehouse and office space
adjacent to and immediately south of the Premises (hereinafter referred to as
the "First Additional Space") and as further described on the attached Exhibit A

                NOW, THEREFORE, the parties agree as follows:

        1. The Lease shall be extended for an additional 60 months commencing
August 1, 1997 and continuing through July 31, 2002.

        2. The First Additional Space shall become subject to the terms of the
Lease upon occupancy by Tenant, which is estimated to be August 1, 1997.
Tenant's total leased area shall increase from approximately 5,000 to 20,000
square feet of warehouse and office space.

        3. Base rent shall be according to the following schedule:

<TABLE>
<CAPTION>
                                                                     BASE RENT
                 PERIOD                                              PER MONTH
                 ------                                              ---------
                 <S>                                                 <C>
                 August 1, 1997 through September 30, 1997           $ 8,219.00
                 October 1, 1997 through July 31, 2002               $15,000.00
</TABLE>

        4. If, after January 31, 2000, Tenant notifies Landlord in writing that
it is desirous of leasing additional space, Landlord shall, providing Tenant is
not then in default, use its best efforts to provide additional space of not
less than 10,000 square feet within one of its properties which is mutually
acceptable to both parties. If Landlord cannot provide such additional space
within 180 days of Landlord's receipt of Tenant's written notice of its desire
to lease additional space, then Tenant shall have the right to terminate the
Lease providing Landlord 30 days' advance written notice of its intent to
terminate.

        5. A tenant improvement allowance of $40,000.00 (hereinafter referred to
as "the Allowance") has been provided. A final space plan will be completed upon
which Landlord and Tenant agree. If Landlord cannot construct the required
improvements within the $40,000.00 allowance, Tenant agrees to pay to Landlord
the amount by which this cost exceeds the Allowance, adjusted by any reductions
or increases in cost initiated by Tenant after a final plan and specifications
have been signed off by both parties with such amount to be paid upon occupancy.
If the tenant improvements, including tenant-initiated adjustments, are less
than the Allowance, Landlord shall credit Tenant by providing Tenant with a like
amount in the form of free base rent.



<PAGE>   20

        6. Landlord shall grant Tenant a one year warranty for the heating,
ventilating, and air conditioning system, provided that Tenant contracts with a
reputable service contractor to provide proper maintenance for the system. Such
warranty shall be in effect for one year beginning August 1, 1997 and continuing
through October 31, 1998.

        7. Except as expressly modified hereby, all terms of the Lease shall
remain in full force and effect and shall continue through the extended term.

        IN WITNESS WHEREOF, the parties hereto have executed this Agreement on
the respective dates set opposite their signatures below, but this Agreement on
behalf of such party shall be deemed to have been dated as of the date first
above written.

                                       LANDLORD:

                                       PACIFIC REALTY ASSOCIATES, L.P.,
                                       a Delaware limited partnership

                                       By:  PacTrust Realty, Inc.,
                                            a Delaware corporation,
                                            its General Partner


Date:   July 3, 1997                   By: /s/ SAM K. BRIGGS
                                           -------------------------------------
                                           Sam K. Briggs
                                           Marketing Director


                                       TENANT:

                                       PI (MEDICAL),
                                       an Oregon corporation


Date:   July 3, 1997                   By:   /s/ RICHARD G. SASS
                                          --------------------------------------
                                       Name: Richard G. Sass
                                            ------------------------------------
                                       Title: CEO
                                             -----------------------------------