Document:

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                                                                   Exhibit 10.20

                       GRAND TRI-STATE CORPORATE CENTRE

                            OFFICE LEASE AGREEMENT

                            1325 TRI-STATE PARKWAY

                               GURNEE, ILLINOIS

                       AFFILIATED RESEARCH CENTERS, INC.

                                   Suite 300
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                                TABLE OF CONTENTS

<TABLE>
<CAPTION>
PARAGRAPH                                                           PAGE
<S>                                                                 <C>
1.       Basic Lease Provisions.....................................   1

2.       Leasing Agreement..........................................   1

3.       Possession, Use and Enjoyment..............................   2

4.       Condition of Premises......................................   2

5.       Base Rent..................................................   5

6.       Rent Adjustment............................................   5

6A.      Security Deposit...........................................   9

7.       Alterations................................................   9

8.       Assignment and Subletting..................................   9

9.       Indemnity..................................................  10

10.      Landlord's Remedies........................................  11

11.      Surrender of Premises......................................  13

12.      Holding Over...............................................  14

13.      Rules and Regulations......................................  14

14.      Damage or Destruction by Casualty..........................  14

15A.     Tenant's Insurance.........................................  15

15B      Landlord's Insurance

16.      Estoppel Certificate.......................................  16

17.      Mortgage By Landlord.......................................  16

18.      Notices....................................................  16

19.      Miscellaneous..............................................  17
</TABLE>

Exhibit A - Floor Plan

Exhibit B - Work Agreement
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Exhibit C -  Working Drawings

Exhibit D - Rules and Regulations

Exhibit E - Unearned Commissions Formula
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                                  OFFICE LEASE

1.      BASIC LEASE PROVISIONS
        ----------------------

<TABLE>
<S>                                            <C>
 A.   Building Address:                        1325 Tri-State Parkway
                                               Gurnee, Illinois

 B.   Landlord & Address:                      T.R.L.P., an Illinois Joint Venture
                                               P.O. Box L
                                               Libertyville, IL 60048

 C.   Tenant & Current Address:                Affiliates Research Centers, Inc. (ARC)
                                               1375 Tri-State Parkway #210
                                               Gurnee, IL 60031

 D.   Date of Lease:                           As of April 10, 1997

 E.   Lease Term:                              Seven (7) Years (84 months)

 F.   Commencement Date of Term:               October 1, 1997 or sooner upon completion

 G.   Expiration Date of Term:                 September 30, 2004

 H.   Annual Base Rent:                        10/1/97-12/31/98:  $354,355.70/Yr.; $23,622.38/Mo
                                               1/1/99-12/31/99:  $293,421.81/Yr.; $24,451.82/Mo
                                               1/1/00-12/31/00:  $303,773.19/Yr.; $25,314.43/Mo
                                               1/1/01-12/31/01:  $314,522.70/Yr.; $26,210.23/Mo
                                               1/1/02-12/31/02:  $325,670.34/Yr.; $27,139.20/Mo
                                               1/1/03-12/31/03:  $337,216.11/Yr.; $28,101.34/Mo
                                               1/1/04-09/30/04:  $261,871.01/Yr.; $29,096.67/Mo

 I.   Rentable Area of Premises:               39,813 sq. ft. or final space plan design

 J.   Rentable Area of Building:               39,813 square feet

 K.   Tenant's Proportionate Share:            100.00%

 L.   Security Deposit:                        An Amount Equal to One month's Rent which is $23,622.38

 M.   Suite No. of Premises:                   300

 N.   Broker:                                  Tri-State Realty, Inc.

 O.   Tax and Expense Pass Thru:               Approx. $2.85/SF (Estimated $1.00/SF for Taxes plus
                                               $1.85/SF fixed rate for operating expenses)
</TABLE>
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     2.   LEASING AGREEMENT. Landlord leases to Tenant and Tenant leases from
Landlord the premises (the "Premises") shown on Exhibit A in the building (the
"Building") located at 1325 Tri-State Parkway, Gurnee, Illinois 60031. The term
of this Lease ("the "Term") shall commence on the date (the "Commencement Date")
which is the earlier to occur of the date stated in Paragraph 1F, or the date
Tenant first occupies all or part of the Premises. The term shall expire on the
date (the "Expiration Date") stated in Paragraph 1G, unless terminated earlier
as otherwise provided in this lease. The Commencement Date and the Expiration
Date may be extended in accordance with Paragraph 5 of Exhibit B.

     3.   POSSESSION, USE AND ENJOYMENT
          -----------------------------

     A.   POSSESSION AND USE OF PREMISES. Tenant shall be entitled to possession
          ------------------------------
of the Premises when the "Work (as defined in Exhibit B) is "substantially
completed" (as defined in Exhibit B), subject to early access to the Premises by
Tenant as provided under Paragraph 6 of Exhibit B. Tenant shall occupy and use
the Premises for general business purposes, including medical research services
and related activities and for no other use. Tenant shall not occupy or use the
Premises or permit the use or occupancy of the Premises for any purpose or in
any manner which:

     1.   is in violation of any applicable statute, law ordinance or
          governmental requirement or rule;

     2.   may be dangerous to persons or property;

     3.   may invalidate or increase the amount of premiums for any policy of
          insurance affecting the Building and if any additional amounts of
          insurance premiums are so incurred, Tenant shall pay to Landlord the
          additional amounts on demand provided, however, that in order for
          tenant to be so liable, Landlord must prove that the increase in
          premium was directly related to tenant's use of the building and even
          if Landlord can provide such relationship, Tenant shall only be liable
          for its prorata share of the increase; or

     4.   may create a nuisance, disturb any other tenant of the Building or the
          occupants or neighboring property or injure the reputation of the
          building.

     B.   QUIET ENJOYMENT. Provided that Tenant is not in default under this
          ---------------
Lease, Tenant shall be entitled to peaceful and quiet enjoyment of the Premises,
subject to the terms of this Lease.

     4.   CONDITION OF PREMISES.
          ---------------------

     A. In the event Tenant has not provided written notice to Landlord of any
obvious defects within sixty (60) days after Tenant takes possession of the
Premises, Tenant shall be deemed to have waived claims relative to obvious
defects. No agreement of Landlord to alter, remodel, decorate, clean or improve
the Premises or the Building, and no representation regarding the condition of
the Premises or the Building has been made by or on behalf of Landlord to
Tenant, except as stated in this Lease. Tenant, at its expense, shall keep the
Premises (including all supplemental or special air condition or ventilating
systems and
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                                                                          Page 3

equipment) in good repair and operating condition and shall promptly repair all
damage to the Premises and said systems and equipment caused by Tenant, or any
of its employees, agents or invitees. (Tenant shall not be required to replace
capital items which fail.)

     B. Except for any damage resulting from the negligence or willful
misconduct of Landlord or its employees, agents and invitees, and subject to the
provisions of Section 15 hereof, Tenant shall at its own expense keep the
Premises and all mechanical installations (including HVAC systems), equipment
and appurtenances used in connection therewith in good repair and tenantable
condition and shall promptly and adequately repair all damage thereto including
replacing or repairing all damaged or broken glass, fixtures and appurtenances
resulting from any such damage, under the supervision and with the approval of
Landlord and within any reasonable period of time specified by Landlord. If
Tenant does not do so promptly and adequately, Landlord may, but need not, make
such repairs and replacements and the cost so incurred by Landlord shall be
deemed Additional Rent under this Lease and shall be payable by Tenant upon the
earlier to occur of (i) Landlord's written demand therefor and (ii) the next due
installment of Rent under this Lease.

     C. Tenant, at its sole cost and expenses shall comply and shall cause the
Premises and all mechanical installations (including HVAC systems) equipment and
appurtenances used in connection therewith to comply with (1) all federal,
state, regional, county, municipal and other governmental statutes, laws, rules,
orders, regulations and ordinances affecting any part of the Premises, or the
use thereof, whether or not any such statutes, laws, rules, orders, regulations
or ordinances which may be hereafter enacted involve a change of policy on the
part of the governmental body enacting the same, and (2) all rules orders and
regulations of the National Board of Fire Underwriters, Landlord's casualty
insurer(s) and other applicable insurance rating organizations or other bodies
exercising similar functions in connection with the prevention of fire or the
correction of hazardous conditions which apply to the Premises. Landlord
warrants that upon occupancy by Tenant all such compliances listed in this
Paragraph 4C have or will have been met for the Premises to the extent possible.

     D. Subject to reimbursement as Expenses pursuant to Paragraph 6 of the
Lease, Landlord shall furnish the following services for the common areas: (1)
Cooled and heated air in season to provide a temperature condition required, in
Landlord's judgment, for comfortable occupancy of the Premises under normal
business operations, Monday through Friday from 8:00 A.M. to 6:00 P.M., and
Saturdays from 8:00 A.M. to 1:00 PM, (Sundays and holidays excepted); (2) cold
water for drinking, lavatory and toilet purposes drawn through fixtures
installed by Landlord, or by Tenant with Landlord's written consent, and hot
water for lavatory purposes drawn from regular Building supply at the prevailing
temperatures; (3) customary janitor service (floors, wastebaskets and ashtrays
only) in and about the Premises, Saturdays, Sundays and holidays excepted.
Window washing shall be furnished at Landlord's discretion; carpeted areas
vacuum cleaned only; and (4) Landlord shall repair and maintain all structural
elements of the Building, the Building's standard mechanical, electrical and
plumbing systems, HVAC systems serving the common areas, rest rooms and common
utilities and keep clean and presentable the common areas.

     E. (1) Use of electricity by Tenant is separately metered. (2) Tenant's use
of electricity shall not exceed the capacity of any electrical conductors and
equipment serving the Premises.
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Tenant shall not make, perform or permit any alterations to wiring or other
electrical facilities in or serving the Premises without the prior consent of
Landlord. If Landlord grants such consent, all additional wiring or other
equipment required therefor shall be installed by Landlord and the cost thereof
shall be promptly paid to Landlord by Tenant upon Landlord's written demand.
Landlord shall not be liable to Tenant for any failure or defect in the supply
or character of electricity, (c) Tenant shall make arrangements directly with
the telephone company servicing the Building for such telephone service in the
Premises desired by Tenant and the cost of all such telephone service (including
the cost of installing all wires and cables) shall be paid for by Tenant If
Tenant desires telegraphic, burglar alarm, computer installations or signal
service, Landlord shall upon request of Tenant direct where and how all
connections for such service shall be introduced and run. In the absence of such
directions, Tenant shall make no borings, cutting or installation of wires or
cables in or about the Premises. The cost of all such installations and service
shall be paid for Tenant.

     F. Tenant agrees (1) that Landlord shall not be liable for damages for
failure to furnish or delay in furnishing any service stated in Paragraph 4(D)
if such failure or delay is caused, in whole or in part, by any one or more of
the events stated in Paragraph 19(I) of the Lease and (2) that no such failure
or delay shall be considered to be an eviction or disturbance of Tenant's use of
the Premises, or relieve Tenant from its obligation to pay all Rent (as defined
in Paragraph 6F of the Lease) when due or from any other obligations of Tenant
under this Lease.

     G. Landlord shall have the following rights exercisable without notice
(except as expressly provided to the contrary) and without being deemed an
eviction or disturbance of Tenant's use or possession of the Premises or giving
rise to any claim for set-off or abatement of Rent: (1) To change the name or
street address of the Building; (2) to install, affix and maintain all signs on
the exterior and/or interior of the Building; (3) to designate and/or approve
prior to installation, all types of signs, window shades, blinds, drapes,
awnings or other similar items, and all internal lighting that may be visible
from the exterior of the Premises; (4) to display the Premises to prospective
tenants at reasonable hours during the last 6 months of the Term; (5) to change
the arrangement of entrances, doors, corridors, elevators and stairs in the
Building, provided that no such change shall materially adversely effect access
to the Premises; (6) to grant to any party the exclusive right to conduct any
business or render any service in or to the Building, provided such exclusive
right shall not operate to prohibit Tenant from using the Premises for the
purposes permitted under this Lease; (7) to prohibit the placing of vending or
dispensing machines of any kind in or about the Premises other than for use by
Tenant's employees; (8) to have access for Landlord and other tenants of the
Building to any mailchutes and boxes located in or on the Premises according to
the rules of the United States Post Office and to discontinue any mailchute
service in the Building, (9) to close the Building between the hours of 8:00
p.m. and 6:00 a.m., except that Tenant and its employees and invitees shall be
entitled to admission at all times under such reasonable regulations as Landlord
prescribes for security purposes; (10) To take any and all reasonable measures,
including inspections and repairs to the Premises or to the Building, as may be
necessary or desirable in the operation or protection of the Building; (11) To
retain at all times master keys or pass keys to the Premises; (11) To install,
operate and maintain security systems which monitor, by closed circuit
television or otherwise, all persons entering and leaving the Building; (12) To
install and maintain pipes, ducts, conduits, wires and structural elements
located in the Premises which serve other parts or other tenants of the
Building; (13) To make alterations, improvements, repairs and replacements
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to the Building or any systems, equipment or machinery located in, on or under
the Building; and (14) To sell, assign or transfer this Lease upon the condition
that in such event this Lease shall remain in full force and effect, subject to
the performance by Tenant of all the terms, covenants and conditions on its part
to be kept, observed and performed. Upon any such sale, assignment or transfer,
other than merely as security, Tenant agrees to look solely to the assignee or
transferee with respect to all matters in connection with the Lease and Landlord
shall be released from any further obligations hereunder as of the date of such
transfer.

     H. Landlord shall finish to Tenant a reasonable number of keys to permit
access to the front door of the Building and to the front door of the Premises.
No duplication of such keys shall be made except by Landlord. If Landlord shall
replace or rekey any door lock due to a key loss by Tenant, Tenant agrees to
indemnify and hold Landlord harmless from all claims, demands, actions,
liabilities, damages, costs and expenses threatened, suffered or incurred by
Landlord, its officers, agents and employees, as a direct or indirect result of
such key loss, including the cost and expense of rekeying or replacing such lock
and of issuing new keys therefor.

     5.   BASE RENT. Tenant shall pay to Landlord base rent ("Base Rent") during
          ---------
the term at the annual rate stated in Paragraph 1H. Base Rent shall be payable
in equal monthly installments in advance on the first day of each calendar month
during the Term. Base Rent shall increase 3.5% on January 1, 1999 and annually
thereafter according to the Annual Base Rent Schedule as stated in Paragraph 1H.

     6.   RENT ADJUSTMENT.
          ---------------

     A.   Definitions.  As used in this Lease,
          -----------

     1.   "Expenses" shall mean all expenses, costs, fees and disbursements paid
          or incurred by or on behalf of Landlord specifically relating to the
          ownership, management, operation, maintenance and repair of the
          building located at 1325 Tri-State Parkway, Gurnee, Illinois, the land
          upon which the Building is situated (the "Land") and the personal
          property and equipment used in connection with the Building or the
          Land. Said expenses shall be reasonable and customary expenses
          normally incurred with like properties and shall not include home
          office expenses, owners' salaries or other expenses not specific to
          the 1325 Tri-State Parkway building. Expenses shall not include any
          costs of alterations of the premises of tenants of the Building,
          interest and principal payments on mortgages, ground rental payments,
          real estate brokerage and leasing commissions, and real estate taxes.
          Management fees shall not exceed 3% of gross receipts collected.

     2.   "Taxes" shall main real estate taxes, sewer rents and charges, which
          Landlord shall become obligated to pay in connection with the Building
          or the land, or both. The Building and the Land are jointly called the
          "Real Property". Taxes for any calendar year shall be Taxes which are
          due for payment or paid in such year rather than Taxes which are
          assessed or become a lien during such year.
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                                                                          Page 6

     3.   Tenant's Proportionate Share" shall mean the percentage stated in
          Paragraph 1K. Tenant's Proportionate Share is determined by dividing
          the rentable area of the Premises (which the parties mutually agree
          contains the area stated in Paragraph 1I by the rentable area of the
          Building (which the parties mutually agree contains the area stated in
          Paragraph 1J which total shall not exceed 100% of the rentable area),
          i.e. 39,813/39,813 = 1.00 or 100%.

     4.   "Additional Rent" shall mean an amount for each calendar year
          occurring entirely or partially within the Term, which shall be
          adjusted as follows:" The amount referred to in Paragraph 10 shall be
          increased or decreased so that the Additional Rent calculated on a
          monthly bases equals Tenant's Proportionate Share of taxes and a fixed
          amount ($1.85 per square foot) for Expenses. By way of example, should
          the Taxes total $15,000, the Tenants Proportionate Share shall be 100%
          thereof or $15,000 (taxes) plus $73,654.05 (expenses) = $88,654.05.
          This amount, $70,500 which by way of this example, is $7,387.84 per
          month, would in such case be the "Additional Rent".

     5.   "Additional Tenant Improvement Rent" shall mean an amount for each
          month occurring entirely or partially within the Term, which shall be
          calculated as follows: The Additional Tenant Improvement Rent shall
          commence upon completion of tenant improvements as stated in Exhibit C
          attached hereto and shall equal the total of tenant improvement
          construction costs amortized at a rate of 9.5% over the remaining
          Lease Term. By way of example, should tenant improvements be completed
          on October 1, 1997, and the total tenant improvement construction
          costs = $700,000.00, this amount ($700,000.00) amortized at a rate of
          9.5% over the remainder of the Lease Term (84 months) = $11,440.79/mo.
          This amount, $11,440.79/mo. or $137,289.48/yr. would in such case be
          the "Additional Tenant Improvement Rent" Such Additional Tenant
          Improvement Rent shall increase 3.5% annually on January 1, 1999 and
          increase 3.5% annually thereafter.

     B.   Payment of Rent. Tenant shall pay Additional Rent, Additional Tenant
          ---------------
Improvement Rent, and Base Rent to Landlord in the following manner:

     1)   Additional Rent. Tenant shall pay to Landlord for each calendar year
          ---------------
occurring entirely or partially within the Term payments ("Progress Payments")
on account of the Additional Rent for such calendar year as follows. Landlord
shall finish to Tenant prior to such calendar year and from time to time during
such calendar year a written notice (a "Projection Notice") setting forth (i)
Landlord's reasonable estimate of Taxes and Expenses for such calendar year and
a detailed basis for such projections, (ii) the Additional Rent for such
calendar year based upon such estimate, and (iii) the monthly Progress Payments
to be made by Tenant for such year based upon such projected Additional Rent.
Until Landlord furnishes a Projection Notice for such calendar year, Tenant
shall pay to Landlord Progress Payments (at the time of and together with each
monthly installment of Base Rent) equal to the latest monthly installment of
Progress Payments for the prior calendar year. On or before the first day of the
month immediately following receipt of a Projection Notice, and on or before the
first day of each following month until Tenant receives a new Projection Notice,
Tenant shall pay to Landlord the
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                                                                          Page 7

monthly installment of Progress Payments shown in the most recent Projection
Notice. Within fifteen (15) days following service of a Projection Notice,
Tenant shall also pay to Landlord a lump sum payment equal to the Progress
Payments owing by Tenant to Landlord (as shown in the Projection Notice) for the
period commencing on the first day of such calendar year and expiring on the
last day of the month in which a new Projection Notice is served, less all
Progress Payments previously paid by Tenant to Landlord for such calendar year.

        2)     Base Rent.  Tenant shall pay Base Rent as shown below:
               ---------

         1.    For the Period October 1, 1997 through December 31, 1998 -
               $7.12/sq.ft. net. Rent is $354,335.70 payable in 15 equal monthly
                ----                                            --
               installments of $23,622.38.

         2.    For the Period January 1, 1999 through December 31, 1999 -
               $7.37/sq.ft. net. Rent is $293,421.81 payable in 12 equal monthly
                ----                                            --
               installments of $24,452.82.

         3.    For the Period January 1, 2000 through December 31, 2000 -
               $7.63/sq.ft. net. Rent is $303,773.19 payable in 12 equal monthly
                ----                                            --
               installments of $25,314.43.

         4.    For the Period January 1, 2001 through December 31, 2001 -
               $7.90/sq.ft. net. Rent is $314,522.70 payable in 12 equal monthly
                ----                                            --
               installments of $26,210.23.

         5.    For the Period January 1, 2002 through December 31, 2002 -
               $8.18/sq.ft. net. Rent is $325,670.34 payable in 12 equal monthly
                ----                                            --
               installments of $27,139.20.

         6.    For the Period January 1, 2003 through December 31, 2003 -
               $8.47/sq.ft. net. Rent is $337,216.11 payable in 12 equal monthly
                ----                                            --
               installments of $28,101.34.

         7.    For the Period January 1, 2004 through September 30, 2004 -
               $8.77/sq.ft. net. Rent is $261,870.01 payable in 9 equal monthly
                ----                                            -
               installments of $29,096.67.

        3)     Additional Tenant Improvement Rent. Additional Tenant Improvement
               ----------------------------------
Rent amounts shall be defined in a future Rider to this Lease and shall commence
upon completion of tenant improvement construction. Tenant shall pay each
installment of Additional Tenant Improvement Rent in installments together with
Base Rent then due.

        4)     Provided Tenant is not in default, Tenant shall have two (2) five
(5) year terms to renew the Lease provided Tenant gives Landlord a six-month
written notice to the expiration of the primary Lease Term and first option Term
pursuant to Paragraph 21. The Base Rent and Additional Tenant Improvement Rent
for each Lease year for the option terms will increase at 4% per year or the
percentage increase in the Consumer Price Index (CPI) for the Chicago Region
from October 1997 to June, 2004 and October, 2004 to June, 2009, respectively
for each option Term; whichever is greater. The "Consumer Price Index" shall be
defined as the regional index published in the Chicago Tribune newspaper -
Business Section.

        C.     Readjustments. After the end of each calendar year and after
               -------------
Landlord shall have determined the actual amounts of Taxes and Expenses to be
used in determining the Additional Rent for such calendar year or such portion
thereof, Landlord shall furnish Tenant a statement ("Landlord's Statement") of
Taxes and Expenses and the Additional Rent owed for such calendar
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                                                                          Page 8

year or portion thereof and, if such Additional Rent exceeds the Progress
Payments paid by Tenant to Landlord for such calendar year, then Tenant shall
pay to Landlord within thirty (30) days after the date of Landlord's Statement,
an amount equal to such excess. If the Progress Payments paid by Tenant to
Landlord for such calendar year exceed the sum of the Additional Rent owed for
such calendar year, then Landlord shall credit such excess to Rent payable after
the date of Landlord's Statement until such excess is exhausted. If this Lease
shall expire or terminate prior to full application of such excess, Landlord
shall pay to Tenant the unapplied balance that is not reasonably required for
payment of Rent Adjustment for the calendar year in which the Lease expires or
terminates less such amounts payable to Landlord as a result of any Tenant
defaults. No interest or penalties shall accrue on any amounts winch Landlord is
obligated to credit or pay to Tenant by reason of this Paragraph 6C.

          D.   Survival. The obligations of Tenant to pay Rent Adjustment and to
               --------
receive refunds of excess amounts paid provided for in this Paragraph 6 shall
survive the expiration or termination of this Lease. Tenant shall pay any
Additional Rent owing to Landlord within fifteen (15) days after the date of
Landlord's Statement for the calendar year in which this Lease expires or
terminates. Provided, however, Tenant's rent adjustment shall equal an amount
for the total year prorated by the number of months during that year that tenant
actually occupied the premises.

          E.   No Decrease in Base Rent. In no event shall the determination of
               ------------------------
any Rent Adjustment owing under this Paragraph 6 result in a decrease in the
Base Rent.

          F.   Payment of Rent. All charges, costs and sums required to be paid
               ---------------
by Tenant under this Lease in addition to Base Rent, Additional Rent, and
Additional Tenant Improvement Rent shall be considered rent. Base Rent and
additional rent are collectively called "Rent". Rent shall be payable without
demand, notice, offset or deduction, except as otherwise specifically stated in
this Lease. All Rent due under this Lease shall be paid by checks payable to the
order of Landlord, which checks shall be mailed or delivered to Landlord at the
location stated in Paragraph lB, or in such other manner or at such other place
as Landlord may from time to time designate to Tenant. Base Rent and Additional
Rent will be prorated for partial months or years within the Term. Tenant's
covenant to pay Rent shall be independent of every other covenant in this Lease.

          G.   Books and Records. Landlord shall maintain books and records of
               -----------------
Expenses and Taxes in accordance with sound accounting and managing practice.
Provided that all Base Rent (including Additional Rent) has been paid in full,
except for amounts which are the subject of a bona fide dispute, the books and
records shall be available to Tenant for inspection upon prior reasonable notice
at the Premises or a location within a ten (10) mile radius thereof.

          6A   SECURITY DEPOSIT. As security for the performance of its
               ----------------
obligations under this Lease, Tenant shall pay to Landlord when Tenant signs
this Lease, a security deposit (the "Security Deposit') in the amount stated in
Paragraph 1L. The Security Deposit may be applied by Landlord to cure any
default of Tenant under this Lease, and upon notice by Landlord of such
application, Tenant shall replenish the Security Deposit in full by promptly
paying to Landlord the amount so applied. Landlord shall not pay any interest on
the Security Deposit. Within thirty (30) days after the Expiration Date,
Landlord shall return to Tenant the balance, if any, of
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                                                                          Page 9

the Security Deposit. The Security Deposit shall not be considered an advance
payment of Rent or a measure of damages for any default by Tenant under this
Lease, nor shall it be a bar or defense to any action which Landlord may at any
time commence against Tenant.

     7.   ALTERATIONS.
          -----------

     A.   Approvals. Without Landlord's prior written consent, which consent
          ---------
shall not be unreasonably withheld, Tenant shall not make or cause to be made
any alterations, improvements, additions, changes or repairs (an "alteration",
collectively) in or to the Premises or the Building. Tenant shall pay the entire
cost of any alteration, and if required by Landlord, shall deposit with Landlord
prior to commencement of such alteration, funds or other security acceptable to
Landlord covering the full cost of such alteration. If such alteration can be
removed without significant damage to the premises, tenant may remove such
alteration. Provided, however, tenant shall restore the premises to their
original condition following the removal of said alteration. Minor alterations
not exceeding $10,000.00 in cost and not involving structural changes may be
made without prior written consent or deposit provided that Tenant gives
Landlord prior written notice.

     B.   Compliance with Laws. Each alteration shall be performed in a good and
          --------------------
workmanlike manner using new, first-class quality materials; in full compliance
with all applicable laws, ordinances and governmental regulations, rules and
requirements; and in full compliance with all insurance rules, orders,
directions, regulations and requirements.

     C.   No Liens. Before any alteration is commenced, Tenant shall give
          --------
Landlord at least fifteen (15) days' prior written notice of same. Tenant shall
not permit any lien or claim for lien of any mechanic, laborer or supplier or
any lien to be filed against the Building or the Land, or any part thereof
arising out of work performed, or alleged to have been performed by, or at the
direction of, or on behalf of Tenant. Tenant agrees to indemnify, hold harmless
and defend Landlord, its officers and employees, from any liability, loss, cost,
damage or expense (including attorneys' fees) arising out of any such lien claim
or out of any other claim relating to work done or materials supplied to the
Premises at Tenant's request or on Tenant's behalf.

     8.   ASSIGNMENT AND SUBLETTING.
          -------------------------

     A.   Consent. Tenant shall not, without the prior written consent of
          -------
Landlord, which consent shall not be unreasonably withheld:

     1)   assign, mortgage, pledge, hypothecate or otherwise transfer or permit
          the transfer of this Lease or the interest of Tenant in this Lease, in
          whole or in part, by operation of law or otherwise;

     2)   sublet all or any part of the Premises (for which the Landlord's
          consent will not unreasonably be withheld); or

     3)   permit the use or occupancy of all or any part of the Premises for any
          purpose not permitted under Paragraph 3, or by anyone other than
          Tenant, Tenant's employees, Tenant's subsidiaries or affiliates.
<PAGE>

                                                                         Page 10

For purposes of this Paragraph 8A an "assignment" shall be considered to include
a change that would negatively affect the net worth of Tenant if Tenant is a
corporation whose stock is not traded publicly.

     B.   No Waiver.  No permitted assignment or sublease shall operate as a
          ---------
waiver by Landlord of, or a release or discharge Tenant from, any liability
under this Lease, whether past, present or future (including liability arising
during any renewal term of this Lease or with respect to any expansion space
included in the Premises), or be considered to be a consent to or relieve Tenant
from obtaining Landlord's consent to any subsequent assignment or sublease.

     C.   Bankruptcy. Without limiting any of the provisions of this Paragraph
          ----------
8, if pursuant to the Federal Bankruptcy Code Tenant is permitted to assign this
Lease notwithstanding the restrictions contained in this Paragraph 8, "adequate
assurance of future performance" by an assignee which is expressly permitted
under such Code shall, to the extent permitted by law, be considered to be the
deposit with Landlord of cash security in an amount equal to the annual Base
Rent plus Rent Adjustment payable under this Lease as of the effective date of
such assignment, which deposit shall be considered an additional security
deposit by Tenant and held and applied by Landlord as provided in Paragraph 6.

     9.   INDEMNITY.
          ---------

     A.   Tenant's Indemnity. Tenant agrees to indemnify and hold harmless
          ------------------
Landlord, its officers, agents, and employees, from and against any and all
claims, demands, actions, liabilities, damages, costs and expenses (including
reasonable attorneys' fees), for injuries to all persons and damage to the
Premises arising from and to the extent of Tenant's negligence in the conduct of
its business or from any activity, work or thing done, permitted or suffered by
Tenant in or about the Premises to any other negligent act or omission of
Tenant, its agents or employees. If any such proceeding is filed against
Landlord or any such indemnified party, Tenant agrees to defend such proceeding
at its sole cost by legal counsel reasonably satisfactory to Landlord, if
requested by Landlord.

     B.   Landlord's Indemnity. Landlord agrees to indemnify and hold harmless,
          --------------------
Tenant, its officers, agents and employees, from and against any and all claims,
demands, actions, liabilities, damages, costs and expenses (including reasonable
attorneys' fees), for injuries to all persons and damages to the Premises
arising from and to the extent of Landlord's negligence in the conduct of its
business or from any activity, work or thing done, permitted or suffered by
Landlord in or about the Premises or any other negligent act or omission of
Landlord, its agents or employees. If any such proceeding is filed against
Tenant or arty such indemnified party, Landlord agrees to defend such proceeding
at its sole cost, by legal counsel reasonably satisfactory to Tenant, if
requested by Tenant.

     C.   To the extent not expressly prohibited by law, Landlord and Tenant
each releases and waives any and all claims for, and rights to recover, damages
against and from the other, and the other's respective agents, partners,
shareholders, officers, directors and employees (collectively, the "Released
Parties"), for loss, damage or destruction to any of its property (including the
Premises, the Building and their coats), the elements of which are insured
against or which would have been insured against had such party suffering such
loss, damage or
<PAGE>

                                                                         Page 11

destruction maintained the property or physical damage insurance policies
required under this Lease. In no event shall this clause be deemed, construed or
asserted (i) to affect or limit any claims or rights against any Released
Parties other than the right to recover damages for loss, damage or destruction
to property, or (ii) to benefit any third party other than the Released Parties.

     10.  LANDLORD'S REMEDIES.
          -------------------

     A. Events of Default. Each of the following shall constitute an event of
        -----------------
default by Tenant under this Lease:

     1)   Tenant fails to pay any installment of rent when due following five
          (5) business days' notice specifying the default delivered or served
          upon Tenant by Landlord;

     2)   Tenant fails to observe or perform any of the other covenants or
          provisions of this Lease to be observed or performed Tenant and fails
          to cure such default within fifteen (15) days after written notice to
          Tenant specifying the default provided, however, that if such default
          is not susceptible to being cured within such 15-day period but Tenant
          promptly commences such cure, said 15-day period shall be extended so
          long as Tenant is actively, diligently and continuously attempting to
          effectuate such cure (and furnishing Landlord with weekly written
          status reports on such efforts) but in no event shall said 15-day
          period be extended by more than 30 days;

     3)   the interest of Tenant in this Lease is levied upon under execution or
          other legal process;

     4)   a petition is filed by or against Tenant to declare Tenant bankrupt or
          seeking a plan of reorganization or arrangement under any Chapter of
          the Bankruptcy Code, or any amendment, replacement or substitution for
          such Code; provided, however, if an involuntary petition is filed
          against Tenant, Tenant shall be permitted 90 days within which to
          challenge said petition;

     5)   a receiver is appointed for Tenant or Tenant's property; or

     6)   Tenant abandons the Premises. Normal business shutdowns by Tenant
          shall not constitute abandonment.

     B.  Landlord's Remedies. Landlord may treat the occurrence of any one or
         -------------------
more of the foregoing events as a breach of this Lease, and thereupon at its
option may, with or without notice or demand of any kind to Tenant or any other
person, have any one or more of the following described remedies (any of which
may be pursued by Landlord in its own name or by and in the name of the
beneficiaries of Landlord or the agent of such beneficiaries) in addition to all
other rights and remedies provided at Jaw or in equity or elsewhere herein:

     1)    Landlord may terminate this Lease and the Term created hereby, in
           which event Landlord may forthwith repossess the Premises and be
           entitled to recover forthwith as damages a sum of money equal to the
           amount of the Rent herein
<PAGE>

                                                                         Page 12

           provided to be paid for the remainder of the Term; provided, however,
           if such amount of damages is not enforceable in law or in equity,
           then Landlord shall be entitled to recover as damages a sum of money
           equal to (A) Rent for the period reasonably required to relet the
           Premises, plus (B) the value of the Rent provided to be paid by
           Tenant for the balance of the original Term, less the rental value of
           the Premises for said period ("Rental Value"), plus (C) the cost
           incurred by Landlord in connection with such termination, including,
           without limitation, brokers' commission, attorneys' fees and costs of
           decorations, repairs, changes, alterations and additions, and (D) any
           other sum of money and damages owed by Tenant to Landlord. Should the
           Rental Value exceed the value of the Rent provided to be paid by
           Tenant for the balance of the original Term of the Lease, Landlord
           shall have no obligation to pay to Tenant the excess or any part
           thereof

     2)    Landlord may terminate Tenant's right of possession and may repossess
           the Premises by forcible entry and detainer suit, by taking peaceful
           possession or otherwise, without terminating this lease, in which
           event Landlord may, but shall be under no obligation to, relet the
           same for the account of Tenant, for such rent and upon such terms as
           shall be satisfactory to Landlord. For the purpose of such reletting,
           Landlord is authorized to decorate or to make any reasonable repairs.
           If Landlord shall fail to relet the Premises, Tenant shall pay to
           Landlord as damages a sum equal to the amount of the Rent reserved in
           this lease for the balance of its original Term. If the Premises are
           relet and a sufficient sum shall not be realized from such reletting
           after paying all of the costs and expenses of such decorations,
           repairs, changes, alterations and additions and the other expenses of
           such relating and of the collection of the rent accruing therefrom to
           equal or exceed the Rent provided for in this lease for the balance
           of its original Term, Tenant shall satisfy and pay such deficiency
           upon demand therefor from time to time. Tenant agrees that Landlord
           may file suit to recover any sums falling due under the terms of this
           Section 10 from time to time and that no suit or recovery of any
           portion due Landlord hereunder shall be any defense to any subsequent
           action brought for any amount theretofore reduced to judgment in
           favor of Landlord.

     C.  If Landlord exercises either of the remedies provided for in
subparagraphs (1) and (2) of the foregoing Section 10B, Tenant shall surrender
possession and vacate the Premises immediately and deliver possession thereof to
the Landlord, and Landlord may then or at any time thereafter re-enter and take
complete and peaceful possession of the Premises, with or without process of
law, full and complete license so to do being hereby granted to the Landlord,
and Landlord may remove all occupants and property therefrom, without being
deemed in any manner guilty of trespass, eviction or forcible entry and detainer
and without relinquishing Landlord's right to rent or any other right given to
Landlord hereunder or by operation of law.

     D.  All property removed from the Premises by Landlord pursuant to any
provisions of this lease or of law may be handled, removed or stored by the
Landlord at the cost and expense of the Tenant, and the Landlord shall in no
event be responsible for the value, preservation or safekeeping thereof provided
that Landlord uses reasonable efforts in the care and preservation thereof.
Tenant shall pay Landlord for all expenses incurred by Landlord in such removal
and storage charges against such property so long as the same shall be in
Landlord's possession or
<PAGE>

                                                                         Page 13

under Landlord's control. All property not removed from the Premises or retaken
from storage by Tenant within thirty (30) days after the end of the Term,
however terminated, shall, at Landlord's election, be conclusively deemed to
have been conveyed by Tenant to Landlord as by bill of sale without further
payment or credit by Landlord to Tenant.

     E.   Bankruptcy. In the event a petition is filed by or against Tenant
          ----------
seeking a plan of reorganization or arrangement under the Federal Bankruptcy
Code, Landlord and Tenant agree, to the extent permitted by law, that the
trustee in bankruptcy shall determine within sixty (60) days after commencement
of the case, whether to assume or reject this Lease.

     F.   Costs and Expenses. Tenant shall pay upon demand, all costs and
          ------------------
expenses, paid or incurred by Landlord in connection with (1) any successful
action or proceeding by Landlord to terminate this Lease or to terminate
Tenant's right to possession of the Premises, (2) any other action or proceeding
by Landlord against Tenant where Landlord is successful on the merits, (3) any
default by Tenant under this Lease (including, without limitation, matters
involving: payment of Base Rent and Rent Adjustment; alterations or other work
in the Premises; and assignment or subletting) whether or not Landlord commences
any action or proceeding against Tenant, (4) any action or proceeding by Tenant
against Landlord in which Tenant fails to obtain a final judgment in its favor
against Landlord, (5) any other appearance by Landlord, or any of its officers,
agents or employees, as a witness or otherwise in any action or proceeding
whatsoever involving or affecting Landlord, Tenant or this Lease provided that
said action or proceeding was not initiated by Landlord, and (6) any assignment
or sublease proposed or granted by Tenant (whether or not permitted under this
Lease) except for any assignments or subletting to subsidiaries or affiliates of
Tenant. Landlord shall pay Tenant upon demand, all costs and expenses, paid or
incurred by Tenant in connection with any successful action or proceeding by
Tenant to terminate this Lease, or any other action or proceeding by Tenant
against Landlord under this Lease where Tenant is successful on the merits.
Tenant's and Landlord's obligations under this Paragraph 10F shall expressly
survive the expiration or earlier termination of this Lease.

     11.  SURRENDER OF PREMISES. Upon the expiration or termination of this
          ---------------------
Lease or termination of Tenant's right to possession of the Premises, Tenant
shall surrender and vacate the Premises immediately and deliver possession of
the Premises to Landlord in a clean, good and tenantable condition, ordinary
wear excepted. Upon any termination which occurs other than by reason of
Tenant's default, Tenant shall be entitled to remove from the Premises all
moveable trade fixtures and personal property of Tenant without credit or
compensation from Landlord, provided, Tenant shall immediately repair all damage
to the Premises or the Building resulting from such removal and shall restore
the Premises to a tenantable condition. In the event possession of the Premises
is not immediately delivered to Landlord or if Tenant shall fail to remove any
moveable trade fixtures or personal property which Tenant is entitled to remove,
Landlord may remove same without any liability to Tenant. Notwithstanding any
other provision of Paragraph 11, Tenant may, in the event of a default by
Landlord, place a reasonable amount required to cover said default into an
escrow account with Chicago Title Insurance (joint order escrow) and the parties
agree to immediate arbitration under the Commercial Rules of Arbitration of the
American Arbitration Association to determine the nature and extent of the
default, if any, and the appropriate disposition of said escrowed funds. Should
Tenant deposit said sums as aforesaid, Tenant shall not be deemed to be in
default.
<PAGE>

                                                                         Page 14

     12.  HOLDING OVER. Tenant shall pay Landlord 200% of the Base Rent plus the
          ------------
Rent Adjustment then applicable for each month or partial month during which
Tenant retains possession of all or any part of the Premises after the
expiration or termination of this Lease. Tenant shall indemnify, defend and hold
harmless Landlord, its officers, agents and employees, from and against any and
all claims, liabilities, actions, losses, damages and expenses asserted against
or sustained by any such party and arising from or by reason of such retention
or possession. The provisions of this paragraph shall not constitute a waiver by
Landlord of any re-entry rights of Landlord available under this Lease or by
law.

     13.  RULES AND REGULATIONS. Tenant shall abide by all rules and regulations
          ---------------------
adopted by Landlord from time to time for the operation and management of the
Building. If any rules and regulations are contrary to the provisions of this
Lease, the provisions of this Lease shall govern. Attached to this Lease as
Exhibit D are the current rules and regulations for the Building. Landlord shall
not be responsible for the violation of any rules or regulations of the Building
by other tenants of the Building. Landlord shall make reasonable efforts to
enforce such rules and regulations with respect to other tenants. Landlord
reserves the right, at any time, to rescind any one or more of these rules and
regulations, or to make such other and further rules and regulations as in
Landlord's judgment may from time to time be necessary for the safety, care and
cleanliness of the Premises and the Building and for the preservation of order
therein.

     14.  DAMAGE OR DESTRUCTION BY CASUALTY. If the Premises or any part of the
          ---------------------------------
Building shall be damaged by fire or other casualty and if such damage does not
render all or a substantial portion of the Premises or the Building
untenantable, then Landlord shall proceed to repair and restore the Premises
with reasonable promptness, subject to reasonable delays fur insurance
adjustments and delays caused by matters beyond Landlord's control. If any such
damage renders all or a substantial portion of the Premises or the Building
untenantable, Landlord may elect to restore the Premises or Building, as the
case may be, or terminate this Lease. Notwithstanding anything to the contrary
herein set forth, Landlord shall have no duty pursuant to this Paragraph 14 to
repair or restore any portion of the alterations, additions or improvements made
by Tenant in the Premises or to expend for any repair or restoration amounts in
excess of insurance proceeds paid to Landlord and available for repair or
restoration.

     In the event any such fire or casualty damage not caused by the act or
neglect of Tenant, its agents or employees, renders the Premises untenantable
and Tenant is not occupying the Premises, and if this lease shall not be
terminated pursuant to the foregoing provisions of this Paragraph 14 by reason
of such damage, then Rent shall abate during the period beginning with the date
of such damage and ending with the date when Landlord completes its repair and
restoration. Such abatement shall be in an amount bearing the same ratio to the
total amount of Rent for such period as the portion of the Premises not ready
for occupancy from time to time bears to the entire Premises. In the event of
termination of this lease pursuant to this Paragraph 14, Rent shall be
apportioned on a per diem basis and be paid to the date of the fire or casualty.

     Not withstanding the foregoing, Landlord's period of time to repair or
restore the Premises shall not exceed thirty (30) days from the date of casualty
or other damage; provided, however, that if Landlord tenders to Tenant
substitute premises substantially similar to the Premises on or before the end
of the thirtieth day following casualty or other damage, Tenant
<PAGE>

                                                                         Page 15

shall have no right to terminate this Lease and may, at its election, either
accept such substitute premises on the same terms as are applicable under this
Lease or continue the above described abatement of rent until the Premises are
repaired and restored.

     15A. TENANT'S INSURANCE. Tenant, at its expense, shall maintain in force at
          ------------------
all times during the Term, comprehensive general public liability insurance,
which shall include coverage for personal liability, contractual liability,
tenant's legal liability, bodily injury, death and property damage, all on an
occurrence basis with respect to the business carried on in or from the Premises
and Tenant's use and occupancy of the Premises. Said insurance policy or
policies shall have the following minimum limits: $1,000,000 for bodily injury
or death to any one person; $1,000,000 for bodily injury or death in the
aggregate; $500,000 for property damage, which shall include coverage for any
loss or damage alleged to have resulted from the loss of use of any property,
real or personal; or such other amounts as Landlord may reasonably require upon
not less than six (6) months' prior written notice, said insurance shall include
Landlord as a named insured and shall protect Landlord in respect of claims by
Tenant as if Landlord were separately insured. Any casualty insurance carried by
Tenant and covering the Premises or Tenant's fixtures, property or equipment
located in the Premises shall contain a waiver by the insurer of any rights of
subrogation or indemnity or any other claim to which the insurer might otherwise
be entitled against Landlord, its officers, agents or employees. Tenant shall
furnish to Landlord, if and whenever requested by Landlord, certificates or
other evidences acceptable to Landlord as to the insurance from time to time
maintained by Tenant and its renewal or continuation in force.

     15B. LANDLORD'S INSURANCE. Landlord shall maintain all risk insurance on
          --------------------
common areas in not less than the amount of $1,000,000. The costs and expenses
of paying and defending against claims, suites, judgments or other proceedings
for personal injuries or property damage concerning the common areas and
exterior of the building and the Land shall not be considered "Expenses" for the
purposes of this definition. Said insurance shall include Tenant as an
additional insured and shall protect Tenant in respect of claims by Landlord as
if Tenant were separately insured. Any casualty insurance carried by Landlord
and covering the Premises or Landlord's fixtures, property or equipment located
in the Premises shall contain a waiver by the insurer of any rights of
subrogation or indemnity or any other claim to which the insurer might otherwise
be entitled against Tenant, its officers, agents or employees. Landlord shall
furnish to Tenant, if and whenever requested by Tenant, certificates or other
evidences acceptable to Tenant as to the insurance from time to time maintained
by Landlord and its renewal or continuation in force.

     15.  ESTOPPEL CERTIFICATE. Tenant shall within ten (10) days after each
          --------------------
written request from Landlord, execute and deliver an estoppel letter with
respect to this Lease in form and substance satisfactory to Landlord signed by
an officer or partner of Tenant in truthfully ascertaining maters regarding this
Lease. Tenant's failure to deliver such statement within said 10-day period
shall be conclusive upon Tenant that this Lease is in full force and effect,
without modification.

     16.  MORTGAGE BY LANDLORD. This Lease is expressly subject and subordinate
          --------------------
at all times to (1) any ground, underlying or operating lease of the Building or
the Land now or hereafter existing and all amendments, renewals and
modifications to any such
<PAGE>

                                                                         Page 16

lease, and (2) the lien of any mortgage or trust deed now or hereafter
encumbering fee title to the Building, the Land and/or the leasehold estate
under any such ground, underlying or operating lease, and to all advances made
or to be made upon the security of such lien. Tenant agrees:

     A. if requested by any mortgagee, trustee or lessor, Tenant shall
subordinate its interest in this Lease to any such mortgage, trust deed or lease
and will execute such subordination agreement or agreements as may be reasonably
required by any said mortgagee, trustee or lessor; and,

     B. in the event of any default by Landlord under this Lease which would
give Tenant the right to terminate this Lease or to claim a partial or total
eviction, Tenant will not exercise any such right until (i) it has notified in
writing the mortgagee, holder of such trust deed or lessor, as the case may be
(if the name and address of such mortgagee, holder or lessor shall have
previously been furnished by written notice to Tenant) of such default, and (ii)
such mortgagee, holder or lessor, as the case may be, fails within a reasonable
time (not to exceed 30 days) after receipt of such notice to cause such default
to be cured; and,

     C. If any such mortgage or trust deed be foreclosed (or a deed given in
lieu of foreclosure), or if any such lease be terminated, upon request of the
mortgagee, holder or lessor, as the case may be, Tenant will attorn to the
purchaser at foreclosure sale (or grantee of deed in lieu of foreclosure) or the
lessor under the lease, as the case may be, and will execute such instruments as
may be necessary or appropriate to evidence such attornment.

     If requested by Tenant and provided Tenant is not in default in the payment
of Rent or in the performance of any of the terms or provisions of this Lease,
Landlord agrees to use reasonable and customary efforts to provide Tenant with a
Non-Disturbance Agreement executed by the mortgagee, holder of such trust deed
or lessor, as the case may be. All of the provisions of Paragraph 17 as stated
above are subject to the mortgagee furnishing a Non-Disturbance Agreement to
Tenant

     17.  NOTICES. All notices and approvals to be given by one party to the
          -------
other party under this Lease shall be given in writing, mailed or delivered as
follows:

     A. To Landlord at P.O. Box L, Libertyville, Illinois 60048, Attention:
                       ----------------------------------------------------
Thomas Rosenquist with a copy to Rob Elbrecht, Tri-State Realty, Inc., 34930 N.
-------------------------------------------------------------------------------
Highway 45, Suite C, Lake Villa, IL, 60046 or to such other person or persons or
------------------------------------------
at such other address or addresses designated by notice to Tenant.

     B. To Tenant as follows: Affiliated Research Centers, Inc. 1325 Tri-State
                              ------------------------------------------------
Parkway #300, Gurnee, IL 60031, Attn: David Adamoli or to such other person or
---------------------------------------------------
persons or at such other address or addresses designated by notice to Landlord.

Notices shall be delivered by hand or by United States certified mail, postage
prepaid, return receipt requested. Notices shall be considered to have been
given upon personal delivery to the addressee or upon posting in the United
States mail as required herein.
<PAGE>

                                                                         Page 17

     18.  MISCELLANEOUS.
          -------------

     A.   Binding Effect. This Lease shall be binding upon and inure to the
          ---------------
benefit of Landlord and Tenant and their respective heirs, legal
representatives, successors and permitted assigns.

     B.   Default Interest. All amounts owing to Landlord under this Lease for
          ----------------
which the date of payment is not expressly fixed, shall be paid within ten (10)
business days after the date Landlord renders appropriate statements of account.
Tenant shall pay Landlord interest on any delinquent Rent or other suns owing
under this Lease at a rate equal to eighteen percent (18%) per annum from the
date due until paid.

     C.   Eminent Domain. In the event that all of the Premises or the Building
          --------------
are taken by eminent domain (or by a deed in lieu of condemnation), this Lease-
shall terminate on the day immediately preceding the date on which possession
thereof is required by the condemning authority. If a substantial part of the
Premises or the Building are taken by eminent domain (or by a deed given in lieu
of condemnation) so that the Premises cannot be reasonably used by Tenant for
the purposes for which they are leased, then either party may terminate this
Lease by giving written notice of termination to "the other party within thirty
(30) days after such taking. In the event of any taking by eminent domain (or
deed given in lieu of condemnation) the entire award shall be paid to and
retained by Landlord excepting, however, that Tenant may receive from such award
the value of any permanent leasehold improvements in the Premises paid for by
Tenant and reasonable costs for the removal and relocation of any tenant trade
fixtures and personal property.

     D.   Exhibits. All Exhibits attached to this Lease are made a part of this
          --------
Lease and incorporated by this reference into this Lease.

     E.   Entire Agreement. This Lease and the Exhibits and Rider (if any)
          ----------------
attached set forth all the covenants, premises, assurances, agreements,
representations, conditions, warranties, statements and understandings
(collectively, the "Representations") between Landlord and Tenant concerning the
Premises and the Building, and there are no Representations, either oral or
written, between them other than those in this Lease. This Lease supersedes and
revokes all previous negotiations, arrangements, letters of intent, offers to
lease, reservations of space, lease proposals, brochures, information conveyed,
whether oral or in writing, between the parties or their respective
representatives or any other person purporting to represent Landlord or Tenant.
No subsequent alteration, amendment, change or addition to this Lease shall be
binding upon Landlord or Tenant unless in writing signed by both parties.

     F.   The signing of this Lease by Tenant and delivery of this Lease to
Landlord or its agent does not constitute a reservation of or option for the
Premises or an agreement to enter into a Lease and this Lease shall become
effective only if and when Landlord signs and delivers same to Tenant.

     G.   No Accord. No payment by Tenant or receipt by Landlord of a lesser
          ---------
amount than any installment or payment of Rent due shall be deemed to be other
than on account of the amount due, and no endorsement or statement on any check
or any letter accompanying any
<PAGE>

                                                                         Page 18

check or payment of Rent shall be considered an accord and satisfaction or limit
Landlord's ability to pursue any other remedies available to Landlord.

     H.   Brokers. The broker in this transaction is Tri-State Realty, Inc. as
          -------                                    --------- ------  ---
identified in Paragraph 1N of this Lease. Landlord represents that Landlord has
dealt directly with and only with the Broker in connection with this Lease and
that insofar as Landlord knows, no other broker negotiated this Lease or is
entitled to any commission in connection herewith. Landlord hereby indemnifies
and holds Tenant, its beneficiaries, owners and owner's agents, harmless from
any and all claims or any other broker or brokers in connection with this Lease.
Landlord shall pay and be responsible for any and all commissions due to the
Broker regarding the negotiation of this Lease.

     I.   Force Majeure. Landlord shall not be considered in default of any of
          -------------
the terms, covenants and conditions of this Lease on Landlord's part to be
performed, if Landlord fails to timely perform any of the terms and such failure
is due in whole or in part to any strike, lockout, labor trouble (whether legal
or illegal), civil disorder, inability to procure materials, failure of power,
restrictive governmental laws and regulations, riots, insurrections, war, fuel
shortages, accidents, casualties, Acts of God, acts caused directly or
indirectly by Tenant (or Tenant's agents, employees or invitees) or any other
cause beyond the control of Landlord.

     J.   No Waiver. The receipt by Landlord of any Rent with knowledge of the
          ---------
breach of any covenant of this Lease by Tenant shall not be deemed a waiver of
such breach or any subsequent breach of this Lease by Tenant and no provision of
this Lease shall be deemed to have been waived by Landlord unless such waiver be
in writing signed by Landlord.

     K.   Paragraphs. Paragraph captions in this Lease are inserted only as a
          ----------
matter of convenience and in no way define, limit, construe or describe the
scope or intent of such Paragraphs.

     L.   Applicable Law. This Lease shall be construed in accordance with the
          --------------
laws of the State of Illinois.

     M.   Time. Time is of the essence of this Lease and the performance of all
          ----
obligations under this Lease.

     N.   Parties' Performance. If either party fails timely to perform any of
          --------------------
its duties under this Lease, the damaged party shall have the right (but not the
obligation) after the expiration of any applicable notice and cure period, to
itself perform such duty on behalf and at the expense of the defaulting party,
without further notice to the defaulting party, and all sums incurred by the
damaged party in performing such duty shall be considered additional rent under
this Lease if the defaulting party is the Tenant and shall be due and payable
upon demand by Landlord. If the Landlord is the defaulting party, all sums
incurred by the Tenant in performing such duty shall become due and payable upon
demand by Tenant.

     O.   Recording. Tenant shall not record this Lease or a memorandum of this
          ---------
Lease.

     P.   Severability. If any clause, phrase, provision or portion of this
          ------------
Lease or the application of same to any person or circumstance shall be invalid
or unenforceable under
<PAGE>

                                                                         Page 19

applicable law, such event shall not affect, impair or render invalid or
application of any clause, phrase, provision or portion of this Lease to other
persons or circumstances.

     Q.   Exculpatory Provisions. The liability of any Landlord under this Lease
          ----------------------
or any amendment to this Lease, or any instrument or document executed in
connection with this Lease, shall be limited to and enforceable solely against
the assets of such Landlord constituting an interest in the Land or Building
(including, where the Landlord is a trustee of a land trust, the subject matter
of the trust) and not other assets of such Landlord. Assets of a Landlord which
is a partnership do not include the assets of the partners of such Landlord, and
negative capital account of a partner in a partnership which is Landlord and an
obligation of a partner to contribute capital to the partnership which is
Landlord shall not be deemed to be assets of the partnership which is Landlord.
No directors, officers, employees or shareholders of any corporation which is
Landlord shall have any personal liability arising from or in connection with
this lease. At any time during which Landlord is trustee of a land trust, all of
the representations, warranties, covenants and conditions to be performed by it
under this Lease or any documents or instruments executed in connection with
this Lease are undertaken solely as trustee, as aforesaid, and not individually,
and no personal liability shall be asserted or be enforceable against it or any
of the beneficiaries under said trust agreement by reason of any of the
representations, warranties, covenants or conditions contained in this Lease or
any documents or instruments executed in connection with this Lease.

     R.   Title. Landlord hereby covenants and agrees that (1) tide to the
          -----
Building of which the Premises are a part is held by Grand National Bank not
personally, but solely as Trustee under a Trust Agreement known as its Trust No.
3252 and (2) Landlord is the sole beneficiary of said Trust and has the right to
execute this Lease on behalf of said Trust.

     S.   Right to Terminate. Provided that Tenant is not in default beyond the
          ------------------
applicable cure period under this Lease, Tenant has the right to terminate up to
50% of the square footage of the Leased Premises as described in this Lease
Agreement (Paragraph 1(1)) effective as of the last day of the forty-eighth (48)
month provided Tenant delivers written notice to Landlord nine (9) months prior
to the end of the applicable termination notice date is date, which notice date
is January 1, 2001 respectively, and Tenant presents a certified check made
payable to Landlord (in an amount to be calculated based upon the square footage
of the Leased Premises so terminated and mutually agreed upon prior to occupancy
of the Leased Premises; said agreement shall be stated in a rider to be attached
to and made a part of this Lease at that time) as consideration to terminate
this Lease. Said "Termination Compensation" shall be calculated as follows:

Total of Additional Tenant Improvement Rent remaining due according to
amortization schedule to be attached upon completion of tenant improvements,
plus unearned commissions multiplied by the percentage of square footage so
terminated up to 50% of the Leased Premises (formula attached as Exhibit F). By
way of example, should the Additional Tenant Improvement Rent remaining due
according to the amortization schedule total $431,694.87, this amount would then
be added to the unearned commissions, which by way of this example = $51,145.32
and the percentage of termination, which by way of this example equals 50%. The
total, $241,420.10 would in such case be the Termination Compensation.
<PAGE>

                                                                         Page 20

This Lease shall remain effective under the same terms and conditions for the
remaining square footage of the Leased Premises and all Base Rent, Additional
Rent, Additional Tenant Improvement Rent and all other expenses shall be reduced
according to the proportionate share remaining.

     EXECUTED this 29th day of April, 1997.

LANDLORD:                                     TENANT:

T.R.L.P., an Illinois Joint Venture, sole     Affiliated Research Centers, Inc.
beneficiary of Grand National Bank & Trust
Company Trust No. 3252

By:     /s/ T.R.L.P.                        By:     /s/ David R. Adamoli
   -------------------------------             -------------------------------
   Its: Managing Partner                       Its: President
       ---------------------------                 ---------------------------
<PAGE>

                                LEASE EXHIBIT A
<PAGE>

                                LEASE EXHIBIT B

                                WORK AGREEMENT

     1.   TENANTS PLANS. On or before May 26, 1997, Tenant shall finish to
Landlord, plans, drawings and specifications ("Tenants Plans", collectively) for
permanent leasehold improvement work (the "Work") which Tenant desires Landlord
to make to the Premises, in sufficient detail to enable Landlord's architects
and engineers to prepare the "Working Drawings" (as defined in Paragraph 2),
together with such additional information as is reasonably necessary to enable
Landlord to prepare the Working Drawings, including a final telephone layout and
special electrical connection requirements, if any. The Work and Tenant's Plans
shall be subject to Landlord's approval, which will not be unreasonably
withheld. Approval by Landlord of the Work and Tenants Plans shall not
constitute any warranty by Landlord to Tenant of the adequacy of the design for
Tenants intended use of the Premises.

     2.   WORKING DRAWINGS. Landlord shall prepare final working drawings and
specifications for the Work (the "Working Drawings') based upon and consistent
with Tenants Plans.

     3.   PERFORMANCE OF THE WORK. Landlord, at its expense, shall perform that
portion of the Work which is necessary to purchase and install in the Premises,
the items described on the Working Drawings (the "Building Standards" ) up to
the quantities shown on Exhibit C. In addition, Landlord, at Tenant's sole
expense, shall be responsible for that portion of the Work which is necessary to
purchase and install in the Premises (i) any Building Standard item in excess of
the quantity specified for such item on Exhibit C, and (ii) any non-Building
Standard item. In the event the work is altered, the costs shall be adjusted by
the units shown. It is agreed and understood by and between the parties that
Annual Base Rent as stated in Paragraph 1G of the Office Lease is based on an
"as is" basis without Tenant Improvements. At such time Tenant so elects,
Landlord agrees to install at Landlord's cost and expense the Building Standard
Improvements according to mutually agreed upon final floor plant All parties
will sign off on construction drawings prior to commencing construction and upon
substantial completion of said improvements in accordance with the plans and
specifications of Landlord and the issuance of a Certificate of Occupancy for
the Leased Premises, Additional Tenant Improvement Rent shall be calculated and
commence.

     4.   PAYMENT. Prior to commencing the performance of the Work, Landlord
will submit to Tenant a written statement of the cost of that portion of the
Work to be paid for by Tenant as above described. Within 7 days after submission
of such statement of cost, Tenant shall sign and deliver to Landlord, in the
form then in use by Landlord, an authorization to proceed with that portion of
the Work to be paid for Tenant and Tenant shall also then pay to Landlord the
amount stated in Landlord's statement No Work shall be commenced until Tenant
has fully complied with the requirements of this Paragraph 4.

     5.   TENANT DELAYS. There shall be no extension of the date stated in
Paragraph 1E of this Lease if the Work has not been substantially completed on
said date by reason of any delay attributable to Tenant, including without
limitation:
<PAGE>

     A.   the failure of Tenant to furnish Tenant's Plans or the other
information required under Paragraph 1 on or before the date stated in Paragraph
1;

     B.   the failure of Tenant to comply with the requirements of Paragraph 4;

     C.   Tenant's requirements for any special materials or finishes or
installations of items other than the Building Standards;

     D.   changes requested by Tenant in Tenants Plans or the Working Drawings
either during the preparation of subsequent to the completion of same;

     E.   the performance of any other work in the Premises by any person, firm
or corporation employed by or on behalf of Tenant, or any failure to complete or
delay in completion of such work; or

     F.   any other act or omission of Tenant.

     6.   TENANTS ACCESS. Landlord grants to Tenant and Tenants agents a license
to enter the Premises prior to the date that the Work is substantially completed
so that Tenant may perform other work required by Tenant to make the Premises
ready for Tenants initial use and occupancy. It shall be a condition precedent
to the right to exercise such license that Tenant give to Landlord not less than
five (5) days' prior written notice of its intention to enter the Premises and
that such access will not interfere with the performance of the Work Such early
access shall be subject to scheduling by Landlord. Tenants agents, contractors,
workmen, mechanics and suppliers shall work in harmony and not interfere with
Landlord and Landlord's agents in the performance of the Work, Landlord's work
in other premises or the general operation of the Building. If at any time such
entry shall cause or threaten to cause disharmony or interference, including
labor disharmony, Landlord may withdraw such license upon notice to Tenant Any
such entry into the Premises by Tenant shall be considered to be under all of
the terms, covenants, conditions and provisions of this Lease, excluding only
the covenant to pay Rent and specifically including the provisions of Paragraph
S of this Lease. Landlord shall not be liable for any injury, loss or damage
which may occur to any of Tenants work or installations made in the Premises or
to property placed in the Premises prior to the Commencement Date and Tenant
shall bear the risk of all such injury, loss or damage. Tenant shall pay for any
damage to the Premises or to any portion of the Work caused Tenant or any of
Tenants employees, agents, contractors, workmen or suppliers. In the event the
performance of any work by Tenant its agents, employees or contractors results
in Landlord incurring costs (including without limitation costs for the use or
movement of labor material) in excess of the customary costs incurred by
Landlord under normal operating and tenant "move-in" procedures established for
the Building by Landlord, Tenant shall reimburse Landlord for such excess costs.
<PAGE>

                                   EXHIBIT C

                                TO BE PROVIDED
<PAGE>

                                 LEASE EXHIBIT D

                              RULES AND REGULATIONS

     1.  Any sign, lettering, picture, notice, legend, direction, figure, logo
or advertisement (collectively, a "Sign") installed, maintained or affixed
within the Premises which is visible from the public corridors within the
Building shall be installed in such manner and be of such color, size,
character, style and materials as Landlord shall approve in writing. No Sign
shall be placed in, on or about the land, the Building; any outside window or
door or in a position to be visible from the outside the Building. Tenant agrees
that upon the termination of this Lease by lapse of time or otherwise, Tenant;
at its sole cost and expense, shall remove all Signs placed on or about the
Premises by Tenant. Tenant, Affiliated Research Centers, Inc., shall be listed
on the general directory sign located at the entrance of the building.

     2.  Sidewalks, entrances, passages, courts, corridors, halls, elevators and
stairways in and about the Building shall not be obstructed nor shall objects be
placed against -- partitions, doors or windows which would be unsightly from the
Building's corridors or from the exterior of the Building.

     3.     No animals, pets, bicycles or other vehicles shall be brought or
permitted to be in the Building or the Premises.

     4.     Tenant shall not conduct or permit any of Tenant's employees to
conduct any room to room canvasses, solicitation, peddling or selling; all of
which are strictly prohibited.

     5.     Tenant shall not waste electricity, water, heat or air conditioning
systems. All controls shall be adjusted only by authorized Building personnel.

     6.     Tenant shall not utilize the Premises in any matter which would
overload the heating, ventilating or air conditioning systems of the Building.

     7.     Tenant shall not permit the use of any apparatus for sound
production or transmission in such manner that the sound so transmitted or
produced shall be audible or vibrations shall be detectable beyond the Premises.

     8.     Tenant shall not utilize any electronic, radiowave, microwave or
other transmitting, receiving or amplification device which would disturb or
interfere with any other tenant of the Building or the operation of the Building
generally but computers and normal business communication equipment shall be
allowed.

     9.     Tenant shall not utilize any equipment or apparatus in such manner
as to create any magnetic fields or waves which adversely affect or interfere
with the operation of any systems or equipment in the Building.

     10.    Tenant shall keep all electrical and mechanical apparatus free of
vibration, noise and air waves which may be transmitted beyond the Premises.
<PAGE>

     11.    All corridor doors shall remain closed at all times.

     12.    No locks or similar devices shall be attached to any door except by
Landlord and Landlord shall have the right to retain a key to all such locks.

     13.    Tenant assumes full responsibility of protecting the Premises from
theft, robbery and pilferage. Except during Tenant's normal business hours,
Tenant shall keep all doors to the Premises locked and other means of entry to
the Premises closed and secured.

     14.    Only machinery or Mechanical devices of a nature directly related to
Tenant's ordinary use of the Premises shall be installed, placed or used in the
Premises and the installation and use of all such machinery and mechanical
devices is subject to the other rules contained in this Lease.

     15.    Except with the prior approval of Landlord, all cleaning repairing;
janitorial, decorating; painting or other services and work in and about the
Premises shall be done only authorized Building personnel or contractors
approved in writing.

     16.    Safes, furniture, equipment, machines and other large or bulky
articles shall be brought to the Building and into and out of the Premises at
such times and in such manner as Landlord shall direct and at Tenants sole risk
and cost Prior to Tenant's removal of such articles from the Building; Tenant
shall obtain written authorization of the office of the Building and shall
present such authorization to a designated employee of Landlord.

     17.    Tenant shall not in any manner deface or damage the Building.

     18.    Inflammables such as gasoline, kerosene, naphtha and benzene, or
explosives, radioactive materials or any other articles of an intrinsically
dangerous nature are not permitted in the Building or the Premises.

     19.    Tenant shall ascertain from Landlord the maximum amount of
electrical current which can safely be used in the Premises, taking into account
the capacity of the electrical wiring of the Building and the Premises and the
needs of other tenants, and shall not use more than such safe capacity.
Landlord's consent to the installation of electrical equipment shall not relieve
Tenant from the obligation not to use more electricity than such safe capacity.

     20.    To the extent permitted by law, Tenant shall use its best efforts
not to permit picketing or other union activity involving its employees in the
Building; except in those locations and subject to time and other limitations as
to which Landlord may give prior written consent.

     21.    Tenant shall not enter into or upon the roof of the Building or any
storage, heating, ventilating, air-conditioning, mechanical or elevator
machinery housing areas.

     22.    Tenant shall not distribute literature, flyers, handouts or
pamphlets of any type in any of the common areas of the Building.
<PAGE>

     23.   Tenant shall not cook, otherwise prepare or sell any food or
beverages in or from the Premises, other than necessary to accommodate Tenant's
employees.

     24.   Tenant shall not permit objectionable odors or vapors to emanate from
the Premises.

     25.   Tenant shall not place a load upon any floor of the Premises
exceeding the floor load capacity for which such floor was designed or allowed
by law to carry.

     26.   Tenant shall not sell nor cause to be sold any items of services at
retail in or from the Premises; nor shall Tenant carry on or permit any employee
or person to carry on or permit any business of machine copying, stenography,
typewriting or similar business in or from the Premises for the service or
accommodation of occupants of any portion of the Building without the written
consent of the Landlord.

     27.   Tenant shall not conduct any auction nor permit any fire or
bankruptcy sale to be held on the Premises.

     28.   Tenant shall obey all parking control measures placed in effect
through the use of signs, identifying decals or other instructions. Seminar
parking or unusual overload parking is not permitted.

     29.   All freight must be moved into, within and out of the Premises under
the supervision of Landlord and according to such regulations as may be
prescribed from time to time.

     30.   All electric wiring on the Premises must be conducted as directed by
Landlord. No boring or cutting for wires is permitted without Landlord's
specific consent The location of telephones, electrical appliances, call boxes,
intercoms, etc. shall be subject to the prior approval Landlord.

     31.   Tenant shall give prompt notice to Landlord of any accidents to or
defects in plumbing or electrical fixtures or heating apparatus so that any
correction or repairs may be properly made.

     32.   No reptiles, animals or birds shall be brought into or kept in the
Premises.

     33.   The Premises shall not be used for housing accommodations or lodging
purposes.

     34.   Tenant shall not install any radio or TV antennae or any structure
in, on or about the Building without the prior written consent and approval of
Landlord, such consent not to be unreasonably withheld.

     35.   Tenant shall not utilize bulbs or lamps in any lighting fixtures
visible to the outside that emit light of a nature which is intermittent;
strobe, flashing or of abnormal hue.

     36.   All window treatments or coverings shall be subject to the prior
written approval of Landlord.
<PAGE>

     37.   Tenant is responsible for supplying any fire extinguisher(s) and/or
first aid kits or other safety materials required by law to be kept and
maintained within the Premises.

     38.   If Tenant desires signal communication, alarm or other utility or
service connections installed or changed in the Premises, the same shall be made
at the sole cost and expense of Tenant, but only upon the prior written consent
and under the direction of Landlord.

     39.   Tenant shall not use or permit the Premises to be used for the
manufacture, sale, distribution by gift or otherwise of any spiritus, fermented
or intoxicating liquors.

     40.   Tenant shall not permit any accumulation of trash, debris or garbage
in or about the Premises and shall properly dispose of all trash, debris and
garbage in waste receptacles provided for such purpose. Tenant shall not place
construction debris in any such waste receptacles and shall make arrangements
acceptable to Landlord for the removal thereof.

     41.   Building is a no smoking facility. There shall be no smoking of
                         -- -------
cigars or cigarettes in or about the premises. This includes leased space,
common areas, Building grounds, and the parking areas.
<PAGE>

                                LEASE EXHIBIT E

                         UNEARNED COMMISSIONS FORMULA

Commission Paid by Landlord
---------- ---- -- --------

Yr 1 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 2 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 3 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 4 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 5 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 6 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 7 annual net Base Rents and Additional Tenant Improvement Rents = Total
Annual Net Rents

Total Annual Net Rents 7 = Average Annual Net Rents

Average Annual Net Rents  x  8%  =  x

Total Annual Net Rents - Average Annual Net Rents = Remaining Net Rents
Remaining Net Rents x 3% = y

x + y = commissions paid by Landlord
- - - - ----------- ---- -- --------

Commissions Earned (assuming Tenant exercises its right to terminate after the
----------- ------ --------- ------ --------- --- ----- -- --------- ----- ---
forty-eight month)
----------- -----

Yr 1 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 2 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 3 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 4 annual net Base Rents and Additional Tenant Improvement Rents = Total
Annual Net Rents

Total Annual Net Rents 4 = Average Annual Net Rents

Average Annual Net Rents x 8% = a

Total Annual Net Rents - Average Annual Net Rents = Remaining Net Rents

Remaining Net Rents x 3% = b

a + b = commissions earned
- - - - ----------- ------

Commissions paid by Landlord - Commissions earned = unearned commissions
<PAGE>

                                    T.R.L.F.

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

                                  P.O. Box L
                            Libertyville, IL 60048
                                (847) 362-2590
September 3, 1998

Mr. Kevin Werner
Affiliated Research Centers, Inc.
1325 Tri-State Parkway #300
Gurnee, IL 60031

         RE:  Lease Termination Compensation Formula

Dear Kevin:

                  Pursuant to Paragraph 19(S) of the Lease Agreement executed as
of April 10, 1997, this letter will serve to formalize the terms of EXHIBIT F as
to lease termination compensation. I have prepared and attached as Exhibit A,
the calculations and formula to be used in the event Affiliated Research
Centers, Inc. wishes to exercise its option to terminate pursuant to said Lease
Agreement Please acknowledge your receipt and acceptance by signing a copy of
this letter. Thank you.

                                        Very truly yours,

                                        T.R.L.P., an Illinois Joint Venture

                                        By:  /s/ Mark Reich
                                           -------------------------------------
                                                  Mark Reich, Managing Partner

/snw

ACKNOWLEDGE AND AGREE THIS 3/rd/ DAY OF SEPTEMBER, 1998

AFFILIATED RESEARCH CENTERS, INC.

By: ________________________________

Encl. - Exhibit A - formula and amortization schedule
<PAGE>

                    LEASE TERMINATION COMPENSATION FORMULA

<TABLE>
<S>                                                                <C>
l0/1/97-12/3198 Base Rent & Additional Tenant Improvement Rent  =  $  668,985.30 +
1/1/99-12/31/99 Base Rent & Additional Tenant Improvement Rent  =  $  553,951.68 +
1/1/00-12/31/00 Base Rent & Additional Tenant Improvement Rent  =  $  573,421.56 +
1/1/01-12/31/01 Base Rent & Additional Tenant Improvement Rent  =  $  593,608.80 +
1/1/02-12/31/02 Base Rent & Additional Tenant Improvement Rent  =  $  614,524.44 +
1/1/03-12/31/03 Base Rent & Additional Tenant Improvement Rent  =  $  636,180.00 +
1/1/04-09/30/04 Base Rent & Additional Tenant Improvement Rent  =  $  493,340.79 =
                                                                   ----------------
Total Annual Net Rents                                          =  $4,134,612.57
</TABLE>

Total Annual Net Rents/7 = Average Annual Net Rents or $590,658.94
Average Annual Net Rents x 8% = x or $47,252.72
Total Annual Net Rents - Average Annual Net Rents = Remaining Net Rents or
$3,543,953.63
Remaining Net Rents x 3% = y or $106,318.61

x + y = commissions paid by Landlord or $153,571.33
- - - - ----------- ---- -- -------- -- -----------

Commissions Earned (assuming Tenant exercises its right to terminate after the
----------- ------ --------- ------ --------- --- ----- -- --------- ----- ---
forty-eight month)
----------- -----

10/1/97-12/31/98 Base Rent &Additional Tenant Improvement Rent = $   668,985.30+
1/1/99-12/31/99 Base Rent & Additional Tenant Improvement Rent = $   553,951.68+
1/1/00-12/31/00 Base Rent & Additional Tenant Improvement Rent = $   573,421.56+
1/1/01-09/30/01 Base Rent & Additional Tenant Improvement Rent = $   445,206.60=
Total Annual Net Rents                                           $ 2,241,565.14
Total Annual Net Rents /4 Average Annual Net Rents or $560,391.29 9
Average Annual Net Rents x 8 % = a or $44,831.30
Total Annual Net Rents - Average Annual Net Rents = Remaining Net Rents or
$1,681,173.85
Remaining Net Rents x 3% = b or $50,435.22
a + b = commissions earned or $95,266.52
- - - - ----------- ------ -- ----------

<TABLE>
<S>                                                                             <C>
Commissions paid by Landlord - Commissions earned = unearned commissions or     $ 58,304.81
Plus Additional Tenant Improvement Costs unpaid as of 09/30/01                  $654,845.95
TOTAL AMOUNT TO BE USED FOR TERMINATION CALCULATION:                            $713,150.76
</TABLE>

$713,150.76 x PERCENTAGE OF SQUARE FOOTAGE (up to 50% of Building or 19,906.5
square feet) OF THE LEASED PREMISES TO BE TERMINATED = TOTAL OF TERMINATION
COMPENSATION
<PAGE>

                                                                          Page 1

                     Loan Schedule for Account "ARC #300"

Pmt              Date              Principal     Interest                Balance
--------------------------------------------------------------------------------
              10/1/97           Rate - 9.50%      New Pmt              20,976.64
              10/1/97           Opening Bal.                        1,283,447.50

Projected Payments

1             10/1/97              10,816.01    10,160.63           1,272,631.49
2             11/1/97              10,901.64    10,075.00           1,261,729.85
3             12/1/97              10,987.96     9,988.69           1,250,741.90
4              1/1/98              11,074.93     9,901.71           1,239,666.97
5              2/1/98              11,162.61     9,814.03           1,228,504.36
6              3/1/98              11,250.98     9,725.66           1,217,253.38
7              4/1/98              11,340.05     9,636.59           1,205,913.33
8              5/1/98              11,429.83     9,546.81           1,194,483.50
9              6/1/98              11,520.31     9,456.33           1,182,963.19
10             7/1/98              11,611.51     9,365.13           1,171,351.68
11             8/1/98              11,703.44     9,273.20           1,159,648.24
12             9/1/98              11,796.09     9,180.55           1,147,852.15
13            10/1/98              11,889.48     9,087.16           1,135,962.67
14            11/1/98              11,983.60     8,993.04           1,123,979.07
15            12/1/98              12,078.47     8,898.17           1,111,900.60
16             1/1/99              12,174.09     8,802.55           1,099,726.51
17             2/1/99              12,270.47     8,706.17           1,087,456.04
18             3/1/99              12,367.61     8,609.03           1,075,088.43
19             4/1/99              12,465.52     8,511.12           1,062,622.91
20             5/1/99              12,564.21     8,412.43           1,050,058.70
21             6/1/99              12,663.68     8,312.96           1,037,395.02
22             7/1/99              12,763.93     8,212.71           1,024,631.09
23             8/1/99              12,864.98     8,111.66           1,011,766.11
24             9/1/99              12,966.82     8,009.82             998,799.29
25            10/1/99              13,069.48     7,907.16             985,729.81
26            11/1/99              13,172.95     7,803.69             972,556.86
27            12/1/99              13,277.23     7,699.41             959,279.63
28             1/1/00              13,382.34     7,594.30             945,897.29
29             2/1/00              13,488.29     7,488.35             932,409.00
30             3/1/00              13,595.07     7,381.57             918,813.93
31             4/1/00              13,702.70     7,273.94             905,111.23
32             5/1/00              13,811.18     7,165.46             891,300.05
33             6/1/00              13,920.51     7,056.13             877,379.54
34             7/1/00              14,030.72     6,945.92             863,348.82
35             8/1/00              14,141.80     6,834.84             849,207.02
36             9/1/00              14,253.75     6,722.89             834,953.27
37            10/1/00              14,366.59     6,610.05             820,586.68
38            11/1/00              14,480.33     6,496.31             806,106.35
39            12/1/00              14,594.98     6,381.68             791,511.39
40             1/1/01              14,710.51     6,266.13             776,800.88
41             2/1/01              14,826.97     6,149.67             761,973.91
42             3/1/01              14,944.35     6,032.29             747,029.56
43             4/1/01              15,062.66     5,913.98             731,966.90
44             5/1/01              15,181.90     5,794.74             716,785.00
45             6/1/01              15,302.09     5,674.55             701,482.91
46             7/1/01              15,423.23     5,553.41             686,059.68
47             8/1/01              15,545.33     5,431.31             670,514.35
48             9/1/01              15,668.40     5,308.24             654,845.95
<PAGE>

                                                                          Page 2

                     Loan Schedule for Account "ARC #300"

Pmt              Date              Principal     Interest                Balance
--------------------------------------------------------------------------------
49            10/1/01              15,792.44     5,184.20             639,053.51
50            11/1/01              15,917.47     5,059.17             623,136.04
51            12/1/01              16,043.48     4,933.16             607,092.56
52             1/1/02              16,170.49     4,806.15             590,922.07
53             211/02              16,298.51     4,678.13             574,623.56
54             3/1/02              16,427.54     4,549.10             558,196.02
55             4/1/02              16,557.59     4,419.05             541,638.43
56             5/1/02              16,688.67     4,287.97             524,949.76
57             6/1/02              16,820.79     4,155.85             508,128.97
58             7/1/02              16,953.95     4,022.69             491,175.02
59             8/1/02              17,088.17     3,888.47             474,086.85
60             9/1/02              17,223.45     3,753.19             456,863.40
61            10/1/02              17,359.80     3,616.84             439,503.60
62            11/1/02              17,497.24     3,479.40             422,006.36
63            12/1/02              17,635.76     3,340.88             404,370.60
64             1/1/03              17,775.37     3,201.27             386,595.23
65             2/1/03              17,916.09     3,060.55             368,679.14
66             3/1/03              18,057.93     2,918.71             350,621.21
67             4/1/03              18,200.89     2,775.75             332,420.32
68             5/1/03              18,344.98     2,631.66             314,075.34
69             6/1/03              18,490.21     2,486.43             295,585.13
70             7/1/03              18,636.59     2,340.05             276,948.54
71             8/1/03              18,784.13     2,192.51             258,164.41
72             9/1/03              18,932.84     2,043.80             239,231.57
73            10/1/03              19,082.72     1,893.92             220,148.85
74            11/1/03              19,233.79     1,742.85             200,915.06
75            12/1/03              19,386.06     1,590.58             181,529.00
76             1/1/04              19,539.54     1,437.10             161,989.46
77             2/1/04              19,694.22     1,282.42             142,295.24
78             3/1/04              19,850.14     1,126.50             122,445.10
79             4/1/04              20,007.28       969.36             102,437.82
80             5/1/04              20,165.67       810.97              82,272.15
81             6/1/04              20,325.32       951.32              61,946.83
82             7/1/04              20,486.23       490.41              41,460.60
83             8/1/04              20,648.41       328.23              20,812.19
84             9/1/04              20,812.19       164.76                   0.00

Opening Date:                     10/1/97
Loan Amount:                      1,283,447.50
Payment Amount:                   20,976.64
Current Interest Rate:            9.50%
Original Length:                  7 Years
Payment Frequency:                Monthly
Compounding Period:               Monthly

Payee:                            trlp
Current Balance:                  1,283,447.50
Remaining Pmts:                   84
Final Pmt Date:                   9/1/04
<PAGE>

                                LEASE EXHIBIT E

                         UNEARNED COMMISSIONS FORMULA

Commissions Paid by Landlord
----------- ---- -- --------

Yr 1 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 2 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 3 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 4 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 5 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 6 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 7 annual net Base Rents and Additional Tenant Improvement Rents = Total
Annual Net Rents

Total Annual Net Rents 7 Average Annual Net Rents

Average Annual Net Rents x 8%= x

Total Annual Net Rents - Average Annual Net Rents = Remaining Net Rents
Remaining Net Rents x 3% = y

x + y = commissions paid by Landlord
- - - - ----------- ---- -- --------

Commissions Earned (assuming Tenant exercises its right to terminate after the
----------- ------ --------- ------ --------- --- ----- -- --------- ----- ---
forty-eight month)
----------- -----

Yr 1 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 2 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 3 annual net Base Rents and Additional Tenant Improvement Rents +
Yr 4 annual net Base Rents and Additional Tenant Improvement Rents = Total
Annual Net Rents

Total Annual Net Rents 4 Average Annual Net Rents

Average Annual Net Rents x 8% = a

Total Annual Net Rents - Average Annual Net Rents = Remaining Net Rents

Remaining Net Rents x 3% = b

a + b = commissions earned
- - - - ----------- ------

Commissions paid by Landlord - Commissions earned = unearned commissions<PAGE>

                                                                    Exhibit 4(i)

Kemper Investors Life Insurance Company
1 Kemper Drive, Long Grove, Illinois 60049-0001

ENDORSEMENT

As used in this endorsement, "Contract" means the Contract or Certificate to
which this endorsement is attached.

This Endorsement forms a part of the contract to which it is attached and is
effective on the issue date.

The contract is amended by removing the last paragraph of the "Withdrawals
During the Accumulation Period" provision which reads as follows:

"You will ratably forfeit any Purchase Payment bonus and related positive
accumulation on any withdrawal in the first Contract Year."

Except as modified herein, all terms and conditions of this contract remain
unchanged.

IN WITNESS WHEREOF, Kemper Investors Life Insurance Company has caused this
Endorsement to be signed by its President and Secretary.

         /s/ Debra P. Rezabek              /s/ Gale K. Caruso
              Secretary                          President

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