<PAGE>

                                                                  EXHIBIT 10.48

MASTER LEASE AGREEMENT


Lessor:        MELLON US LEASING, A DIVISION OF        Lessee:
               MELLON LEASING CORPORATION
Address:       525 Market Street, Suite 3500           Address:
               San Francisco, CA 94105-2743


                           TERMS AND CONDITIONS OF LEASE

     The undersigned Lessee hereby requests Lessor to purchase the personal 
property described in any Equipment Schedule hereunder (herein called 
"Equipment") from the supplier(s) listed in any Equipment Schedule hereunder 
(herein called "Vendor" and/or "Manufacturer", as applicable) and to lease 
the Equipment to Lessee on the terms and conditions of the lease set forth 
below.

     Lessor hereby leases to Lessee, and Lessee hereby leases from 
Lessor, the Equipment upon the following terms and conditions:

     1. NO WARRANTIES BY LESSOR.  Lessee has selected the Equipment and may 
have entered into certain purchase, licensing, or maintenance agreements with 
the Vendor and/or Manufacturer (herein referred to as an "Acquisition 
Agreement") covering the Equipment as further described in Paragraph 26 
hereof.  If Lessee has entered into any Acquisition Agreement, each agreement 
shall provide for certain rights and obligations of the parties thereto with 
respect to the Equipment, and Lessee shall perform all of the obligations set 
forth in each Acquisition Agreement as if this lease did not exist.  LESSOR 
MAKES NO WARRANTY, EXPRESS OR IMPLIED, AS TO ANY MATTER WHATSOEVER, INCLUDING 
THE CONDITION OF THE EQUIPMENT, ITS MERCHANTABILITY OR ITS FITNESS FOR ANY 
PARTICULAR PURPOSE, AND, AS TO LESSOR, LESSEE LEASES THE EQUIPMENT "AS IS."  
LESSOR SHALL HAVE NO LIABILITY FOR ANY LOSS, DAMAGE OR EXPENSE OF ANY KIND 
WHATSOEVER RELATING THERETO, INCLUDING WITHOUT LIMITATION ANY SPECIAL, 
INDIRECT, INCIDENTAL OR CONSEQUENTIAL DAMAGES OF ANY CHARACTER.

     2. CLAIMS AGAINST VENDOR AND/OR MANUFACTURER.  If the Equipment is not 
properly installed, does not operate as represented or warranted by Vendor 
and/or Manufacturer, or is unsatisfactory for any reason, Lessee shall make 
any claim on account thereof solely against Vendor and/or Manufacturer 
pursuant to the Acquisition Agreement, if any, and shall, nevertheless, pay 
Lessor all rent payable under this lease.  All warranties from Vendor and/or 
Manufacturer are, to the extent they are assignable, hereby assigned to 
Lessee for the term of the lease or until an Event of Default occurs 
hereunder, for Lessee's exercise at Lessee's expense.  Lessee may directly 
inquire with Vendor and/or Manufacturer to receive an accurate and complete 
statement of such warranties, including any disclaimers or limitations of 
such warranties or of any remedies with respect thereto.

     3. VENDOR NOT AN AGENT.  Lessee understands and agrees that neither 
Vendor, nor any sales representative or other agent of Vendor, is an agent of 
Lessor. Sales representatives or agents of Vendor, and persons that are not 
employed by Lessor (including brokers and agents) are not  authorized to 
waive or alter any term or condition of this lease, and no representation as 
to the Equipment or any other matter by Vendor or any other person that is 
not employed by Lessor (including brokers and agents) shall in any way affect 
Lessee's duty to pay the rent and perform its other obligations as set forth 
in this lease.

     4. NON-CANCELLABLE LEASE.  This lease and any Equipment Schedule hereto 
cannot be cancelled or terminated except as expressly provided herein.  
Lessee agrees that its obligation to pay all rent and other sums payable 
hereunder and the rights of Lessor in and to such rent are absolute and 
unconditional and are not subject to any abatement, reduction, setoff, 
defense, counterclaim or recoupment due or alleged to be due to, or by reason 
of, any past, present or future claims which Lessee may have against Lessor, 
any assignee, any Manufacturer or Vendor, or against any person for any 
reason whatsoever.

     5. ORDERING EQUIPMENT.  Lessee shall arrange for delivery of the 
Equipment so that it can be accepted in accordance with Paragraph 6 hereof 
within 90 days after the date on which Lessor accepts Lessee's offer to enter 
into this lease with respect to any Equipment Schedule or by such other date 
as may be set forth in an Equipment Schedule or Approval Letter issued by 
Lessor as the Approval Expiration Date.  Unless otherwise specified on the 
Equipment Schedule, Lessee shall be responsible for all transportation, 
packing, installation, testing and other charges in connection with the 
delivery, installation and

                                                                    Page 1 of 7
<PAGE>

use of the Equipment.  Lessee hereby authorizes Lessor to insert in any 
Equipment Schedule hereunder the serial numbers and other identification data 
of Equipment when determined by Lessor.

     6. ACCEPTANCE.  Lessee acknowledges that for purposes of receiving or 
accepting the Equipment from Vendor, Lessee is acting on Lessor's behalf.  
Upon delivery of the Equipment to Lessee and Lessee's inspection thereof, 
Lessee shall furnish Lessor a written statement (a) acknowledging receipt of 
the Equipment in good condition and repair and (b) accepting it as 
satisfactory in all respects for the purposes of this lease (the "Certificate 
of Acceptance"). Unless otherwise set forth in the applicable Equipment 
Schedule, the  first day of the month  following receipt and acceptance of 
the Equipment covered by an Equipment Schedule shall be the Rent Commencement 
Date therefor .  However, should Lessee have a previous lease with Lessor 
which is active at the time of acceptance of the Equipment under the 
Equipment Schedule and said lease and the current Equipment Schedule 
hereunder shall have the same invoice address then the Rent Commencement Date 
shall occur in the month immediately following acceptance of the Equipment on 
the rent payment due date established with Lessee for said previous active 
lease. Lessor is authorized to fill in on any Equipment Schedule hereunder 
the Rent Commencement Date in accordance with the foregoing.

     7. TERMINATION BY LESSOR.  If, by the Approval Expiration Date, the 
Equipment described in any Equipment Schedule has not been delivered to 
Lessee and accepted by Lessee as provided in Paragraph 6 hereof, or if other 
conditions of Lessor's Approval Letter, if any, have not been met, then 
Lessor may, at its option, terminate this lease and its obligations hereunder 
with respect to such Equipment Schedule at any time after the expiration of 
such 90 days or any date after the Approval Expiration Date, as applicable.  
Lessor shall give Lessee written notice whether or not it elects to exercise 
such option within 10 days after Lessor's receipt of Lessee's written request 
for such notice.

     8. TERM.  The term of this lease shall be comprised of an  Interim Term 
and an Initial Term.  The Interim Term shall commence on the date the 
Certificate of Acceptance is executed by Lessee (the "Acceptance Date") and 
terminate on the Rent Commencement Date.  The Initial Term of the Lease shall 
begin on the Rent Commencement Date, and shall terminate on the later of (i) 
the last day of the last month of the Initial Term (as that Term is set forth 
in the applicable Equipment Schedule hereto) or (ii) the date Lessee fulfills 
all Lessee's obligations hereunder. 

     9. RENTAL. The rental amount payable to Lessor by Lessee for the 
Equipment will be set forth in the Equipment Schedule(s) ("Rental Amount").  
As the first rent payment for the Equipment, Lessee shall pay Lessor in 
immediately available funds on the Rent Commencement Date the sum of, (i) the 
Rental Amount, and (ii) Interim Rent in an amount equal to 1/30th of the 
Rental Amount times the number of days from and including the  Acceptance 
Date through but excluding the Rent Commencement Date, and subsequent rent 
payments shall be due on the same day of each calendar period as indicated on 
the Equipment Schedule for the balance of the Initial Term.  Rent payments 
shall be due whether or not Lessee has received any notice that such payments 
are due.  All rent payments shall be paid to Lessor at its address set forth 
on the Equipment Schedule or as otherwise directed by Lessor in writing.

     10. RENEWAL.  If no default shall have occurred and be continuing, 
Lessee shall be entitled to renew the lease with respect to all, but not less 
than all, of the Equipment covered by an Equipment Schedule  for a minimum 12 
month period at an amount equal to the fair market rental value thereof,  in 
use and operational, in the condition required by the lease, payable on a 
periodic basis, as mutually agreed by Lessor and Lessee ("Renewal Rent").  
Lessee must give Lessor written notice of its intention to exercise said 
option, which notice must be received by Lessor at least 90 days before 
expiration of the Initial Term.  The first installment of the Renewal Rent 
shall be due at expiration of the Initial Term of the lease.  Should Lessee 
fail to comply with the provisions described above covering renewal, upon 
expiration of the Initial Term, the term of the lease shall be automatically 
extended for a term of 3 months.  Thereafter, the term of the lease will be 
extended for subsequent full month periods, on a month to month basis, until 
Lessee has given at least 90 days written notice terminating the lease.  Such 
termination will take effect upon completion of all Lessee's obligations 
under the lease (including payment of all periodic rental payments due during 
such 90 day period, as provided in Paragraph 9 of the lease).  At any time 
after the expiration of the Initial Term, if the lease has been automatically 
extended as set forth herein, Lessor reserves the right to terminate the 
lease by 30 days written notice to Lessee.

     11. LOCATION; INSPECTION; LABELS.  The Equipment shall be delivered to 
and shall not be removed without Lessor's prior written consent from the 
"Equipment Location" shown on the related Equipment Schedule, or if none is 
specified, Lessee's billing address shown on the Equipment Schedule.  Lessor 
shall have the right to inspect the Equipment at any reasonable time.  If 
Lessor supplies Lessee with labels stating that the Equipment is owned by 
Lessor, Lessee shall affix such labels to and keep them in a prominent place 
on the Equipment.

     12. REPAIRS; USE; ALTERATIONS.  Lessee, at its own cost and expense, shall
keep the Equipment in good repair  and working order, in the same condition as
when delivered to Lessee, reasonable wear and tear excepted, and in accordance
with

                                                                    Page 2 of 7

<PAGE>

the manufacturer's recommended specifications; shall use the Equipment 
lawfully;  shall not alter the Equipment without Lessor's prior written 
consent, shall use the Equipment in compliance with any existing 
Manufacturer's service and warranty requirements and any insurance policies 
applicable to the Equipment and shall furnish all parts and servicing 
required therefor.  All parts, repairs, additions, alterations and 
attachments placed on or incorporated into the Equipment which cannot be 
removed without damage to the Equipment shall immediately become part of the 
Equipment and shall be the property of the Lessor.  Lessee will obtain and 
maintain all permits, licenses and registrations necessary to lawfully 
operate the facility where the Equipment is located. Lessee shall comply with 
all applicable environmental and industrial hygiene laws, rules and 
regulations (including but not limited to federal, state, and local 
environmental protection, occupational, health and safety or similar laws, 
ordinances and restrictions).  Lessee shall, not later than 5 days after the 
occurrence, provide Lessor with copies of any report required to be filed 
with governmental agencies regulating environmental claims.  Lessee shall 
immediately notify Lessor in writing of any existing, pending or threatened 
investigation, inquiry, claim or action by any governmental authority in 
connection with any law, rule or regulation relating to industrial hygiene or 
environmental conditions that could affect the Equipment.

     13. MAINTENANCE.  If the Equipment is such that Lessee is not normally 
capable of maintaining it, Lessee, at its expense, shall enter into and 
maintain in full force and effect throughout the Initial Term, and any 
renewal term, Vendor and/or Manufacturer's standard maintenance contract, and 
shall comply with all its obligations thereunder.  An alternate source of 
maintenance may be used with Lessor's prior written consent.  Such consent 
shall be granted if, in Lessor's reasonable opinion, the Equipment will be 
maintained in an equivalent state of good repair, condition and working order.

     14. SURRENDER.  Provided that Lessee does not exercise the purchase 
option as set forth in Paragraph 28 hereof, upon the expiration of the 
Initial Term, or any renewal term, or upon demand by Lessor made pursuant to 
Paragraph 22 of the lease, Lessee, at its expense, shall return all, but not 
less than all, of the Equipment by delivering it to such place or on board 
such carrier, packed for shipping, as Lessor may specify.  Lessee agrees that 
the Equipment, when returned, shall be in the same condition as when 
delivered to Lessee, reasonable wear and tear excepted, and in a condition 
which will permit Lessor to be eligible for Manufacturer's standard 
maintenance contract without incurring any expense to repair or rehabilitate 
such Equipment.  Lessee shall be liable for reasonable and necessary expenses 
to place the Equipment in such condition. Lessee shall remain liable for the 
condition of the Equipment until it is received and accepted at the 
destination designated by Lessor as set forth above.  If any items of 
Equipment are missing or damaged when returned, such occurrence shall be 
treated as an event of Loss or Damage with respect to such missing or damaged 
items and shall be subject to the terms specified in Paragraph 15 below.  
Lessee shall provide Lessor with a Letter of Maintainability from the 
Manufacturer of the Equipment, which letter shall state that the Equipment 
will be eligible for the Manufacturer's standard maintenance contract when 
sold or leased to a third party.  Lessee shall give Lessor prior written 
notice that it is returning the Equipment as provided above, and such notice 
must be received by Lessor at least 90 days prior to such return.  Should 
Lessee fail to comply with the provisions described above covering surrender, 
upon expiration of the Initial Term, the term of the lease shall be 
automatically extended for a term of 3 months.  Thereafter, the term of the 
lease will be extended for subsequent full month periods, on a month to month 
basis, until Lessee has given at least 90 days written notice terminating the 
lease.  Such termination will take effect upon completion of all Lessee's 
obligations under the lease (including payment of all periodic rental 
payments due during such 90 day period, as provided in Paragraph 9 of the 
lease).  At any time after the expiration of the Initial Term, if the lease 
has been automatically extended as set forth herein, Lessor reserves the 
right to terminate the lease by 30 days written notice to Lessee.

     15. LOSS OR DAMAGE.  Lessee shall bear the entire risk of loss, theft, 
destruction of or damage to the Equipment or any item thereof (herein "Loss 
or Damage") from any cause whatsoever.  No Loss or Damage shall relieve 
Lessee of the obligation to pay rent or of any other obligation under this 
lease.  In the event of Loss or Damage, Lessee, at the option of Lessor, 
shall:  (a) place the same in good condition and repair; (b) replace the same 
with like equipment acceptable to Lessor in good condition and repair with 
clear title thereto in Lessor; or (c) pay to Lessor the total of the 
following amounts:  (i) the total rent and other amounts due and owing at the 
time of such payment, plus (ii) an amount calculated by Lessor which is the 
present value at 5% per annum simple interest discount of all rent and other 
amounts payable by Lessee with respect to said item from date of such payment 
to date of expiration of its Initial Term, plus (iii) the "reversionary 
value" of the Equipment, which shall be determined by Lessor as the total 
cost of the Equipment less 60% of the total rent (net of sales/use taxes, if 
any) required to be paid pursuant to Paragraph 9.  Upon Lessor's receipt of 
such payment, Lessee and/or Lessee's insurer shall be entitled to Lessor's 
interest in said item, for salvage purposes, in its then condition and 
location, "as-is", without any warranty, express or implied.

     16. INSURANCE.  Lessee shall provide, maintain and pay for (a) all risk 
property insurance against the loss or theft of or damage to the Equipment, 
for the full replacement value thereof, naming Lessor as a loss payee, and 
(b) commercial general liability insurance (and if Lessee is a doctor, 
hospital or other health care provider, medical malpractice insurance).  All 
such policies shall name Lessor as an additional insured and shall have 
combined single limits in amounts acceptable to Lessor.  All such insurance 
policies shall be endorsed to be primary and non-contributory to any policies 
maintained by Lessor.  In addition Lessee shall cause Lessor to be named as 
an additional insured on any excess or umbrella policies purchased by Lessee. 
A copy of each paid-up policy evidencing such insurance (appropriately 
authenticated by the insurer) or a certificate of the insurer providing such 

                                                                    Page 3 of 7

<PAGE>

coverage proving that such policies have been issued, providing the coverage 
required hereunder shall be delivered to Lessor prior to the Rent 
Commencement Date.  All insurance shall be placed with companies satisfactory 
to Lessor and shall contain the insurer's agreement to give 30 days written 
notice to Lessor before cancellation or any material change of any policy of 
insurance.

     17. TAXES.  Lessee shall reimburse to Lessor (or pay directly if, but 
only if, instructed by Lessor) all charges and taxes (local, state and 
federal) which may now or hereafter be imposed or levied upon the sale, 
purchase, ownership, leasing, possession or use of the Equipment; excluding, 
however, all income taxes levied on (a) any rental payments made to Lessor 
hereunder, (b) any payment made to Lessor in connection with Loss or Damage 
to the Equipment under Paragraph 15 hereof, or (c) any payment made to Lessor 
in connection with Lessee's exercise of its purchase option under Paragraph 
28 hereof. 

     18. LESSOR'S PAYMENT.  If Lessee fails to provide or maintain said 
insurance, to pay said taxes, charges and fees, or to discharge any levies, 
liens and encumbrances created by Lessee, Lessor shall have the right, but 
shall not be obligated, to obtain such insurance, pay such taxes, charges and 
fees, or effect such discharge.  In that event, Lessee shall remit to Lessor 
the cost thereof with the next rent payment.

     19. INDEMNITY. (a) GENERAL INDEMNITY.  Lessee shall indemnify Lessor 
against and hold Lessor harmless from any and all claims, actions, damages, 
costs, expenses including reasonable attorneys' fees, obligations, 
liabilities and liens (including any of the foregoing arising or imposed 
under the doctrines of "strict liability" or "product liability" and 
including without limitation the cost of any fines, remedial action, damage 
to the environment and cleanup and the fees and costs of consultants and 
experts), arising out of the manufacture, purchase, lease, ownership, 
possession, operation, condition, return or use of the Equipment, or by 
operation of law, excluding however, any of the foregoing resulting from the 
gross negligence or willful misconduct of Lessor.  Lessee agrees that upon 
written notice by Lessor of the assertion of such a claim, action, damage, 
obligation, liability or lien, Lessee shall assume full responsibility for 
the defense thereof.  Lessee's choice of counsel shall be mutually acceptable 
to both Lessee and Lessor.  This indemnity also extends to any environmental 
claims arising out of or relating to prior acts or omissions of any party 
whatsoever.  The provisions of this paragraph shall survive termination of 
this lease with respect to events occurring prior to such termination.

     (b) TAX INDEMNITY.  Lessee acknowledges that Lessor shall be entitled to 
all tax benefits of ownership with respect to the Equipment (the "Tax 
Benefits"), including but not limited to, (i) the accelerated cost recovery 
deductions determined in accordance with Section 168(b)(1) of the Internal 
Revenue Code of 1986 for the Equipment based on the original cost of the 
Equipment to Lessor (ii) deductions for interest on any indebtedness incurred 
by Lessor to finance the Equipment and (iii) sourcing of income and losses 
attributable to this lease to the United States.  Lessee represents that the 
Equipment shall be depreciable for Federal tax purposes utilizing the MACRS 
Recovery Period as set forth in the Equipment Schedule, with such 
depreciation commencing as of the date of Equipment acceptance by Lessee as 
set forth on the Certificate of Acceptance.  Lessee agrees to take no action 
inconsistent with the foregoing or any action which would result in the loss, 
disallowance or unavailability to Lessor of all or any part of the Tax 
Benefits.  Lessee hereby indemnifies and holds harmless Lessor and its 
assigns from and against (i) the loss, disallowance, unavailability or 
recapture of all or any part of the Tax Benefits resulting from any action, 
statement, misrepresentation or breach of warranty or covenant by Lessee of 
any nature whatsoever including but not limited to the breach of any 
representations, warranties or covenants contained in this paragraph, plus 
(ii) all interest, penalties, fines or additions to tax resulting from such 
loss, disallowance, unavailability or recapture, plus (iii) all taxes 
required to be paid by Lessor upon receipt of the indemnity set forth in this 
paragraph.  Any payments made by Lessee to reimburse Lessor for lost Tax 
Benefits shall be calculated (i) on the assumption that Lessor is subject to 
the maximum Federal Corporate Income Tax with respect to each year and that 
all Tax Benefits are currently utilized, and (ii) without regard to whether 
Lessor or any members of a consolidated group of which Lessor is also a 
member is then subject to any increase in tax as a result of the loss of Tax 
Benefits.  For the purposes of this paragraph, "Lessor" includes for all tax 
purposes the consolidated taxpayer group of which Lessor is a part.

     (c)  PAYMENT.  The amounts payable pursuant to this Paragraph 19 shall 
be payable upon demand of Lessor, accompanied by a statement describing in 
reasonable detail such claim, action, damage, cost, expense, fee, obligation, 
liability, lien or tax and setting forth the computation of the amount so 
payable, which computation shall be binding and conclusive upon Lessee, 
absent manifest error.  The indemnities and assumptions of liabilities and 
obligations contained in this Paragraph 19 shall continue in full force and 
effect notwithstanding the expiration or other termination of this Lease.
 
     20. ASSIGNMENT.  Without Lessor's prior written consent, Lessee shall 
not assign, transfer, pledge, hypothecate or otherwise dispose of this lease, 
the Equipment, or any interest therein.  Without Lessor's prior written 
consent, Lessee shall not sublet or lend the Equipment or permit it to be 
used by anyone other than Lessee or Lessee's employees. Lessor may assign 
this lease in whole or in part without notice to Lessee.  If Lessee is given 
notice of such assignment it agrees to acknowledge receipt thereof in 
writing.  Each such assignee shall have all of the rights, but none of the 
obligations, of Lessor under this lease.  Lessee shall not assert against 
assignee any defense, counterclaim or offset that Lessee may have against 
Lessor.  Notwithstanding any

                                                                    Page 4 of 7

<PAGE>

such assignment, Lessor warrants that Lessee shall quietly enjoy use of the 
Equipment subject to the terms and conditions of this lease so long as Lessee 
is not in default hereunder.  Subject to the foregoing, this lease inures to 
the benefit of and is binding upon the successors and assigns of the parties 
hereto.

     21. DELINQUENT PAYMENTS.  (a) Service Charge.  Since it would be 
impractical or extremely difficult to fix Lessor's actual damages for 
collecting and accounting for a late payment, if any payment to Lessor 
required herein (including, but not limited to, rental, renewal, tax, 
purchase and other amounts) is not paid on or before its due date, Lessee 
shall pay to Lessor an amount equal to 5% of any such late payment.  (b)  
Interest.  Lessee shall also pay interest on any such late payment from the 
due date thereof until the date paid at the lesser of 18% per annum or the 
maximum rate allowed by law.

     22. DEFAULT; REMEDIES.  Any of the following shall constitute an Event 
of Default:  If a) Lessee fails to pay when due any rent or other amount 
required herein to be paid by Lessee, or b) Lessee makes an assignment for 
the benefit of creditors, whether voluntary or involuntary, or c) a petition 
is filed by or against Lessee under any bankruptcy, insolvency or similar 
legislation, or d) Lessee violates or fails to perform any provision of 
either this lease or any Acquisition Agreement, or violates or fails to 
perform any covenant or representation made by Lessee herein, or e) Lessee 
makes a bulk transfer of furniture, furnishings, fixtures or other equipment 
or inventory, or f) Lessee ceases doing business as a going concern or 
terminates its existence, or (g) Lessee consolidates with, merges with or 
into, or conveys or leases all or substantially all of its assets as an 
entirety to any person or engages in any other form of reorganization, or 
there is a change in the legal structure of Lessee, in each case which 
results, in the opinion of Lessor, in a material adverse change in Lessee's 
ability to perform its obligations under this lease, or (h) any 
representation or warranty made by Lessee in this lease or in any other 
document or agreement furnished by Lessee to Lessor shall prove to have been 
false or misleading in any material respect when made or when deemed to have 
been made, or i) Lessee shall be in default under any material obligation for 
the payment of borrowed money or the deferred purchase price of, or for the 
payment of any rent due with respect to, any real or personal property, or j) 
Lessee shall be in default under any other agreement now existing or 
hereafter made with Lessor or any of Lessor's affiliates, or k) any event or 
condition described in the foregoing clauses (b), (c), (e), (f), (g) (h) (in 
clauses (g) and (h) substituting the phrase "guaranty or other credit support 
document" for the word "lease"), (i) or (j) shall have occurred with respect 
to any guarantor of, or other party liable in whole or in part for, Lessee's 
obligations hereunder, or such guarantor or other party shall have defaulted 
in the observance or performance of any covenant, condition or agreement to 
be observed or performed by it under the guaranty or other credit support 
document pursuant to which it is liable for Lessee's obligations hereunder, 
or such guaranty or other credit support document shall have been revoked or 
terminated or shall have otherwise ceased, for any reason, to be in full 
force and effect.  An Event of Default with respect to any Equipment Schedule 
shall constitute an Event of Default for all Equipment Schedules.  Lessee 
shall promptly notify Lessor of the occurrence of any Event of Default.

     If an Event of Default occurs, Lessor shall have the right to exercise 
any one or more of the following remedies in order to protect the interests 
and reasonably expected profits and bargains of Lessor:  a) Lessor may 
terminate this lease with respect to all or any part of the Equipment, b) 
Lessor may recover from Lessee all rent and other amounts then due and as 
they shall thereafter become due hereunder, c) Lessor may take possession of 
any or all items of Equipment, wherever the same may be located, without 
demand or notice, without any court order or other process of law and without 
liability to Lessee for any damages occasioned by such taking of possession, 
and any such taking of possession shall not constitute a termination of this 
lease, d) Lessor may recover from Lessee, with respect to any and all items 
of Equipment, and with or without repossessing the Equipment the sum of (1) 
the total amount due and owing to Lessor at the time of such default, plus 
(2) an amount calculated by Lessor which is the present value at 5% per annum 
simple interest discount of all rent and other amounts payable by Lessee with 
respect to said item(s) from date of such payment to date of expiration of 
its Initial Term, plus (3) the "reversionary value" of the Equipment, which 
shall be determined by Lessor as the total cost of the Equipment less 60% of 
the total rent (net of sales/use taxes, if any) required to be paid pursuant 
to Paragraph 9, and which the parties agree is a reasonable estimate of such 
value; and upon the payment of all amounts described in clauses (1), (2) and 
(3) above, Lessee will become entitled to the Equipment AS IS, WHERE IS, 
without warranty whatsoever; provided, however, that if Lessor has 
repossessed or accepted the surrender of the Equipment, Lessor shall sell, 
lease or otherwise dispose of the Equipment in a commercially reasonable 
manner, with or without notice and on public or private bid, and apply the 
net proceeds thereof (after deducting all expenses, including attorneys' fees 
incurred in connection therewith), to the sum of (1), (2) and (3) above, and 
e) Lessor may pursue any other remedy available at law or in equity, 
including but not limited to seeking damages or specific performance and/or 
obtaining an injunction.

     No right or remedy herein conferred upon or reserved to Lessor is 
exclusive of any right or remedy herein or by law or equity provided or 
permitted; but each shall be cumulative of every other right or remedy given 
hereunder or now or hereafter existing at law or in equity or by statute or 
otherwise, and may be enforced concurrently therewith or from time to time, 
but Lessor shall not be entitled to recover a greater amount in damages than 
Lessor could have gained by receipt of Lessee's full, timely and complete 
performance of its obligations pursuant to the terms of this lease plus 
accrued delinquent payments under Paragraph 21.

                                                                    Page 5 of 7

<PAGE>

     23. LESSOR'S EXPENSE.  Lessee shall pay Lessor all costs and expenses, 
including attorneys' fees and the fees of collection agencies, incurred by 
Lessor in enforcing any of the terms, conditions, or provisions hereof or in 
protecting Lessor's rights herein.  Lessee's obligation hereunder includes 
all such costs and expenses expended by Lessor (a) prior to filing of an 
action, (b) in connection with an action which is dismissed, and (c) in the 
enforcement of any judgment.  Lessee's obligation to pay Lessor's attorneys' 
fees incurred in enforcing any judgment is a separate obligation of Lessee, 
severable from Lessee's other obligations hereunder, which obligation will 
survive such judgment and will not be deemed to have been merged into such 
judgment.

     24. OWNERSHIP; PERSONAL PROPERTY.  The Equipment shall at all times 
remain the property of Lessor and Lessee shall have no right, title or 
interest therein or thereto except as expressly set forth in this lease and 
the Equipment shall at all times be and remain personal property 
notwithstanding that the Equipment or any part thereof may now be, or 
hereafter become, in any manner, affixed or attached to real property or any 
improvements thereon.

     25. NOTICES.  Service of all notices under this lease shall be 
sufficient if given personally or mailed to the respective party at its 
address set forth on any Equipment Schedule, or at such address as either 
party may provide in writing from time to time.  Any such notice mailed to 
said address shall be effective when deposited in the United States mail, 
duly addressed and with postage prepaid.

     26. ACQUISITION AGREEMENTS.  If the Equipment is subject to any 
Acquisition Agreement, Lessee, as part of this lease, transfers and assigns 
to Lessor all of its rights, but none of its obligations (except for Lessee's 
obligation to pay for the Equipment conditioned upon Lessee's acceptance in 
accordance with Paragraph 6), in and to the Acquisition Agreement, including 
but not limited to the right to take title to the Equipment.  Lessee shall 
indemnify and hold Lessor harmless in accordance with Paragraph 19 from any 
liability resulting from any Acquisition Agreement as well as liabilities 
resulting from any Acquisition Agreement Lessor is required to enter into on 
behalf of Lessee or with Lessee for purposes of this lease.

     27. UPGRADES.  Any existing lease between Lessor and Lessee subject to 
an "upgrade" program shall continue in full force and effect and shall be 
kept free of default by Lessee (even if the Equipment covered by the existing 
lease is sold, traded-in, etc.) until any such existing lease is cancelled by 
Lessor when, if applicable, the new Equipment is accepted by Lessee for all 
purposes of this lease.

     28. PURCHASE OPTION.  If no default shall have occurred and be 
continuing, Lessee shall be entitled, at its option upon written notice to 
Lessor, which notice must be received by Lessor at least 90 days prior to the 
end of either the Initial Term or any renewal term of any Equipment Schedule, 
to purchase all, but not less than all, of the Equipment covered by such 
Equipment Schedule from Lessor at the end of the Initial Term or any renewal 
term for such Equipment Schedule at a purchase price equal to the then fair 
market value of the Equipment in use and operational, in the condition 
required by the lease, as mutually agreed by Lessor and Lessee.  On a date 
which is no later than the expiration date of the Initial Term or any renewal 
term, as applicable, Lessee shall pay to Lessor the purchase price for the 
Equipment covered by such Equipment Schedule (plus any taxes levied thereon) 
and Lessor shall sell the Equipment "as-is where-is" without any warranties 
express or implied.

     29. RELATED EQUIPMENT SCHEDULES.  In the event that any Equipment 
Schedule hereunder shall include Equipment that may become attached to, 
affixed to, or used in connection with Equipment covered under another 
Equipment Schedule hereunder ("Related Equipment Schedule"), Lessee 
acknowledges the following: (a) if Lessee elects to exercise a purchase 
option or renewal option under any Equipment Schedule, if provided; or (b) if 
Lessee elects to return the Equipment under any Equipment Schedule as 
described in Paragraph 14, then Lessor, at its discretion, may require the 
similar disposition of all Related Equipment Schedules as provided for by 
this lease.

     30. MISCELLANEOUS.  This instrument and any Approval Letter issued by 
Lessor and any Equipment Schedule hereunder constitutes the entire agreement 
between Lessor and Lessee, and shall not be amended, altered or changed 
except by a written agreement signed by the parties hereto, and in the case 
of Lessor, such agreement shall not be valid unless executed by Lessor at 
Lessor's home office.  To the extent any provision of this lease may be 
determined to be invalid or unenforceable, it shall be ineffective without 
affecting the other provisions of this lease.  To the extent permitted by 
applicable law, Lessee hereby waives any provisions of law which render any 
provision of this lease unenforceable in any respect.  Unless specified 
otherwise, in the event such written agreement is attached to and made a part 
of an Equipment Schedule, the terms and conditions of said written agreement 
shall apply only to said Equipment Schedule and shall not apply to any other 
Equipment Schedule made a part of this lease.  In the event Lessee issues a 
purchase order to Lessor covering Equipment to be leased hereunder, it is 
agreed that such purchase order is issued for purposes of authorization and 
Lessee's internal use only, and none of its terms and conditions shall modify 
the terms and conditions of this lease and/or related documentation, or 
affect Lessor's responsibility to Lessee as defined in this lease.  An 
executed Equipment Schedule that incorporates by reference the terms of this 
Master Lease Agreement, marked "Original," shall be the original of the lease 
for the Equipment described therein for all purposes. All other executed 
counterparts

                                                                    Page 6 of 7

<PAGE>

of the lease shall be marked "Duplicate."  To the extent the lease 
constitutes chattel paper, as such term is defined in the Uniform Commercial 
Code of the applicable jurisdiction, no security interest in the lease may be 
created through the transfer of possession of any counterpart other than the 
Original of the lease.  Lessor reserves the right to charge Lessee fees for 
its provision of additional administrative services related to the lease 
requested by Lessee.  Lessee shall provide Lessor with such corporate 
resolutions, opinions of counsel, financial statements, and other documents 
(including documents for filing or recording) as Lessor may request from time 
to time.  LESSEE HEREBY APPOINTS LESSOR OR ITS ASSIGNEE ITS TRUE AND LAWFUL 
ATTORNEY IN FACT TO EXECUTE ON BEHALF OF LESSEE ALL UNIFORM COMMERCIAL CODE 
FINANCING STATEMENTS OR OTHER DOCUMENTS WHICH, IN LESSOR'S DETERMINATION, ARE 
NECESSARY TO SECURE LESSOR'S INTEREST IN SAID EQUIPMENT.  The filing of UCC 
Financing Statements is precautionary and shall not be evidence that the 
lease is intended as security.  If for any reason this agreement is 
determined not to be a lease, Lessee hereby grants Lessor a security interest 
in the lease, the Equipment or collateral pertaining thereto and the proceeds 
thereof, including re-lease, sale or disposition of the Equipment or other 
collateral.  If more than one Lessee is named in this lease, the liability of 
each shall be joint and several.  Time is of the essence with respect to this 
lease.  Lessee represents and warrants that the Equipment is being leased 
hereunder for business purposes. The descriptive headings which are used in 
this lease are for convenience of the parties only and shall not affect the 
meaning of any provision of the lease. Any failure of the Lessor to require 
strict performance by the Lessee or any waiver by Lessor of any provision 
herein shall not be construed as a consent or waiver of any other breach of 
the same or of any other provision.  This agreement shall be governed by the 
laws of the state of California (without giving effect to principles of 
conflicts of law thereof).

     31.  LESSEE'S REPRESENTATIONS; WAIVER OF JURY TRIAL.  Lessee represents 
and warrants, as of the date of this lease:  (a) Lessee is duly organized, 
validly existing and in good standing under the laws of the state of its 
incorporation or organization, and is duly qualified to do business wherever 
necessary to carry on its present business and operations and to own its 
property; (b) this lease (and any Equipment Schedule entered into pursuant to 
this lease) has been duly authorized by all necessary action on the part of 
Lessee, duly executed and delivered by authorized officers or agents of 
Lessee, does not require any further shareholder or partner approval, does 
not require the approval of, or the giving notice to, any federal, state, 
local or foreign governmental authority, does not contravene any law binding 
on Lessee or contravene any certificate or articles of incorporation or 
by-laws or partnership certificate or agreement, or any agreement, indenture 
or other instruments to which Lessee is a party or by which it or any of its 
assets or property may be bound; (c) this lease (and any Equipment Schedule 
entered into pursuant to this lease) constitutes the legal, valid and binding 
obligation of Lessee and is enforceable in accordance with its terms; (d) all 
credit and financial information, and all other information submitted to 
Lessor at any time is true and correct, and there does not exist any pending 
or threatened action or proceeding before any court or administrative agency 
which might materially adversely affect Lessee's financial condition or 
operations; (e) Lessee agrees to furnish to Lessor (i) as soon as available, 
and in any event within 120 days after the last day of each fiscal year of 
Lessee, a copy of the financial statements of Lessee as of the end of such 
fiscal year, certified by an independent certified public accounting firm; 
(ii) as soon as available, and in any event within 60 days after the last day 
of each quarter of Lessee's fiscal year, a copy of quarterly financial 
statements certified by the principal financial officer of Lessee; and (iii) 
such additional information concerning Lessee as Lessor may reasonably 
request. LESSEE AND LESSOR HEREBY WAIVE THE RIGHT TO TRIAL BY JURY OF ANY 
MATTERS ARISING OUT OF THIS LEASE OR ANY OTHER AGREEMENT EXECUTED IN 
CONNECTION HEREWITH.

     32. GOOD FAITH DEPOSIT REQUIREMENT.  Lessee agrees, with respect to each 
transaction, to pay the Good Faith Deposit specified in Lessor's proposal for 
such transaction or in the Equipment Schedule related thereto.  This Good 
Faith Deposit is given in consideration for Lessor's costs and expenses in 
investigating and appraising and/or establishing credit for Lessee.  This 
Good Faith Deposit shall not be refunded unless Lessor declines to accept 
Lessee's offer to enter into the lease.  Upon Lessor's acceptance of Lessee's 
offer to enter into the lease, unless otherwise specified in the proposal or 
Equipment Schedule, the amount shall be applied to the first period's rent 
payment. Lessee acknowledges that Lessor's act of depositing any Good Faith 
Deposit into Lessor's bank account shall not in itself constitute Lessor's 
acceptance of Lessee's offer to enter into the lease.

IN WITNESS WHEREOF, the parties have executed this Master Lease Agreement 
effective as of the first date it is executed by Lessee below. 

<TABLE>

<S>                                             <C>                                                 <C>
MELLON US LEASING, A DIVISION OF                LESSEE . . . .                                      DATE
MELLON LEASING CORPORATION (LESSOR)
BY                                              BY   /s/ Elizabeth L. Hougen      Controller        9/29/97
------------------------------------------      ----------------------------------------------    -----------
TITLE                                           BY                                  TITLE

------------------------------------------      ----------------------------------------------    -----------
HOME OFFICE: 525 MARKET STREET, SUITE 3500      CO-LESSEE . . . .                                    DATE
SAN FRANCISCO, CA  94105-2743                   BY                                  TITLE
NOT VALID UNLESS EXECUTED BY LESSOR AT LESSOR'S 
HOME OFFICE                                     ----------------------------------------------    -----------

</TABLE>

                                                                    Page 7 of 7