Voting Agreement - Gilead Sciences Inc.


                                   VOTING AGREEMENT

     THIS VOTING AGREEMENT is entered into as of February __, 1999, by and
between GILEAD SCIENCES, INC., a Delaware corporation ('Parent'), and ________
___________ ('Stockholder').

                                       RECITALS

     A.   Parent, Gazelle Acquisition Sub, Inc., a Delaware corporation and a
wholly owned subsidiary of Parent ('Merger Sub'), and NeXstar Pharmaceuticals,
Inc., a Delaware corporation (the 'Company'), are entering into an Agreement and
Plan of Merger of even date herewith (the 'Merger Agreement') which provides
(subject to the conditions set forth therein) for the merger of Merger Sub into
the Company (the 'Merger').

     B.   In order to induce Parent and Merger Sub to enter into the Merger
Agreement, Stockholder is entering into this Voting Agreement.

                                      AGREEMENT

     The parties to this Voting Agreement, intending to be legally bound, agree
as follows:

SECTION 1.     CERTAIN DEFINITIONS.

          For purposes of this Voting Agreement:

          (a)  'COMPANY COMMON STOCK' shall mean the common stock, par value
$.01 per share, of the Company.

          (b)  'EXPIRATION DATE' shall mean the earlier of (i) the date upon
which the Merger Agreement is validly terminated, or (ii) the date upon which
the Merger becomes effective.

          (c)  Stockholder shall be deemed to 'OWN' or to have acquired
'OWNERSHIP' of a security if Stockholder: (i) is the record owner of such
security; or (ii) is the 'beneficial owner' (within the meaning of Rule 13d-3
under the Securities Exchange Act of 1934) of such security.

          (d)  'PERSON' shall mean any (i) individual, (ii) corporation, limited
liability company, partnership, trust or other entity, or (iii) governmental
authority.

          (e)  'SUBJECT SECURITIES' shall mean: (i) all securities of the
Company (including all shares of Company Common Stock and all options, warrants
and other rights to acquire shares of Company Common Stock) Owned by Stockholder
as of the


                                           


date of this Voting Agreement; and (ii) all additional securities of the Company
(including all additional shares of Company Common Stock and all additional
options, warrants and other rights to acquire shares of Company Common Stock) of
which Stockholder acquires Ownership during the period from the date of this
Voting Agreement through the Expiration Date.

          (f)  A Person shall be deemed to have a effected a 'TRANSFER' of a
security if such Person directly or indirectly: (i) sells, pledges, encumbers,
grants an option with respect to, transfers, distributes or disposes of such
security or any interest in such security; or (ii) enters into an agreement or
commitment contemplating the possible sale of, pledge of, encumbrance of, grant
of an option with respect to, transfer of or disposition of such security or any
interest therein.

SECTION 2.     TRANSFER OF SUBJECT SECURITIES.

     2.1  TRANSFEREE OF SUBJECT SECURITIES TO BE BOUND BY THIS VOTING AGREEMENT.
Stockholder agrees that, during the period from the date of this Voting
Agreement through the Expiration Date, Stockholder shall not cause or permit any
Transfer of any of the Subject Securities to be effected unless each Person to
which any of such Subject Securities, or any interest in any of such Subject
Securities, is or may be Transferred shall have: (a) executed a counterpart of
this Voting Agreement and a proxy in the form attached hereto as Exhibit A (with
such modifications as Parent may reasonably request); and (b) agreed to hold
such Subject Securities (or interest in such Subject Securities) subject to all
of the terms and provisions of this Voting Agreement.

     2.2  NO TRANSFER OF VOTING RIGHTS.  Stockholder shall ensure that, during
the period from the date of this Voting Agreement through the Expiration Date:
(a) none of the Subject Securities is deposited into a voting trust; and (b) no
proxy is granted, and no voting agreement or similar agreement is entered into,
with respect to any of the Subject Securities.

SECTION 3.     VOTING OF SHARES.

     3.1  VOTING AGREEMENT.  Stockholder agrees that, during the period from the
date of this Voting Agreement through the Expiration Date:

          (a)  at any meeting of stockholders of the Company, however called,
     Stockholder shall (unless otherwise directed in writing by Parent) cause
     all outstanding shares of Company Common Stock that are Owned by
     Stockholder as of the record date fixed for such meeting to be voted in
     favor of the approval and adoption of the Merger Agreement and the approval
     of the Merger, and in favor of each of the other actions contemplated by
     the Merger Agreement; and


                                          2


          (b)  in the event written consents are solicited or otherwise sought
     from stockholders of the Company with respect to the approval or adoption
     of the Merger Agreement, with respect to the approval of the Merger or with
     respect to any of the other actions contemplated by the Merger Agreement,
     Stockholder shall (unless otherwise directed in writing by Parent) cause to
     be validly executed, with respect to all outstanding shares of Company
     Common Stock that are Owned by Stockholder as of the record date fixed for
     the consent to the proposed action, a written consent or written consents
     to such proposed action.

     3.2  PROXY; FURTHER ASSURANCES.

          (a)  Contemporaneously with the execution of this Voting Agreement:
(i) Stockholder shall deliver to Parent a proxy in the form attached to this
Voting Agreement as Exhibit A, which shall be irrevocable to the fullest extent
permitted by law, with respect to the shares referred to therein (the 'Proxy');
and (ii) Stockholder shall cause to be delivered to Parent an additional proxy
(in the form attached hereto as Exhibit A) executed on behalf of the record
owner of any outstanding shares of Company Common Stock that are owned
beneficially (within the meaning of Rule 13d-3 under the Securities Exchange Act
of 1934), but not of record, by Stockholder.

          (b)  Stockholder shall, at Stockholder's own expense, perform such
further acts and execute such further documents and instruments as may
reasonably be required to vest in Parent the power to carry out and give effect
to the provisions of this Voting Agreement.

SECTION 4.     WAIVER OF APPRAISAL RIGHTS.

     Stockholder hereby irrevocably and unconditionally waives, and agrees to
cause to be waived and to prevent the exercise of, any rights of appraisal, any
dissenters' rights and any similar rights relating to the Merger or any related
transaction that Stockholder or any other Person may have by virtue of the
ownership of any Subject Securities.

SECTION 5.     NO SOLICITATION.

     During the period from the date of this Voting Agreement through the
Expiration Date, Stockholder shall not, nor shall Stockholder authorize or
permit any of Stockholder's Representatives (as defined in the Merger Agreement)
to, directly or indirectly: (i) solicit, initiate or encourage the submission or
announcement of any Takeover Proposal (as defined in the Merger Agreement); 
(ii) participate in any discussions or negotiations regarding, or furnish to any
Person any information with respect or in response to, or take any other action
to facilitate any inquiries or the making of any proposal that constitutes, or
may reasonably be expected to lead to, any


                                          3


Takeover Proposal; or (iii) induce or encourage any other stockholder of the
Company to vote against, or to fail to vote in favor of, the approval and
adoption of the Merger Agreement, the approval of the Merger or any of the other
actions contemplated by the Merger Agreement.  Stockholder shall immediately
cease and discontinue, and Stockholder shall ensure that Stockholder's
Representatives immediately cease and discontinue, any existing discussions with
any Person that relate to any Takeover Proposal. Nothing contained in this
Section 5 shall prevent Stockholder, when acting solely in his capacity as a
director or officer of the Company, from causing the Company to take the actions
specified in the proviso to the first sentence of Section 4.16 of the Merger
Agreement (to the extent all of the conditions set forth in such proviso have
been satisfied).

SECTION 6.     REPRESENTATIONS AND WARRANTIES OF STOCKHOLDER.

     Stockholder hereby represents and warrants to Parent as follows:

     6.1  AUTHORIZATION, ETC.  Stockholder has the absolute and unrestricted
right, power, authority and capacity to execute and deliver this Voting
Agreement and the Proxy and to perform Stockholder's obligations hereunder and
thereunder.  This Voting Agreement and the Proxy constitute legal, valid and
binding obligations of Stockholder, enforceable against Stockholder in
accordance with their terms, subject to (i) laws of general application relating
to bankruptcy, insolvency and the relief of debtors, and (ii) rules of law
governing specific performance, injunctive relief and other equitable remedies.

     6.2  NO CONFLICTS OR CONSENTS.

          (a)  The execution and delivery of this Voting Agreement and the Proxy
by Stockholder do not, and the performance of this Voting Agreement and the
Proxy by Stockholder will not: (i) conflict with or violate any law, rule,
regulation, order, decree or judgment applicable to Stockholder or by which
Stockholder or any of Stockholder's properties is or may be bound or affected;
or (ii) result in or constitute (with or without notice or lapse of time) any
breach of or default under, or give to any other Person (with or without notice
or lapse of time) any right of termination, amendment, acceleration or
cancellation of, or result (with or without notice or lapse of time) in the
creation of any encumbrance or restriction on any of the Subject Securities
pursuant to, any contract to which Stockholder is a party or by which
Stockholder or any of Stockholder's affiliates or properties is or may be bound
or affected, except in the case of clause (i) or (ii) above where any of such
events would not have a material adverse effect on Stockholder or otherwise
impair Stockholder's ability to satisfy Stockholder's obligations hereunder.


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          (b)  The execution and delivery of this Voting Agreement and the Proxy
by Stockholder do not, and the performance of this Voting Agreement and the
Proxy by Stockholder will not, require any consent or approval of any Person.

     6.3  TITLE TO SECURITIES.  As of the date of this Voting Agreement:  (a)
Stockholder holds of record (free and clear of any encumbrances or restrictions)
the number of outstanding shares of Company Common Stock set forth under the
heading 'Shares Held of Record' on the signature page hereof; (b) Stockholder
holds (free and clear of any encumbrances or restrictions) the options, warrants
and other rights to acquire shares of Company Common Stock set forth under the
heading 'Options and Other Rights' on the signature page hereof; (c) Stockholder
Owns the additional securities of the Company set forth under the heading
'Additional Securities Beneficially Owned' on the signature page hereof; and (d)
Stockholder does not directly or indirectly Own any shares of capital stock or
other securities of the Company, or any option, warrant or other right to
acquire (by purchase, conversion or otherwise) any shares of capital stock or
other securities of the Company, other than the shares and options, warrants and
other rights specified on the signature page hereof.

     6.4  ACCURACY OF REPRESENTATIONS.  The representations and warranties
contained in this Voting Agreement are accurate in all material respects as of
the date of this Voting Agreement, will be accurate in all material respects at
all times through the Expiration Date and will be accurate in all material
respects as of the date of the consummation of the Merger as if made on that
date.

SECTION 7.     ADDITIONAL COVENANTS OF STOCKHOLDER.

     7.1  FURTHER ASSURANCES.  From time to time and without additional
consideration, Stockholder shall (at Stockholder's sole expense) execute and
deliver, or cause to be executed and delivered, such additional transfers,
assignments, endorsements, proxies, consents and other instruments, and shall
(at Stockholder's sole expense) take such further actions, as Parent may
reasonably request for the purpose of carrying out and furthering the intent of
this Voting Agreement.

     7.2  LEGEND.  Immediately after the execution of this Voting Agreement (and
from time to time upon the acquisition by Stockholder of Ownership of any shares
of Company Common Stock prior to the Expiration Date), Stockholder shall ensure
that each certificate evidencing any outstanding shares of Company Common Stock
or other securities of the Company Owned by Stockholder and which are held in
certificated form bears a legend in the following form:

     THE SECURITY OR SECURITIES REPRESENTED BY THIS CERTIFICATE MAY NOT BE SOLD,
     EXCHANGED OR OTHERWISE TRANSFERRED OR


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     DISPOSED OF EXCEPT IN COMPLIANCE WITH THE PROVISIONS OF THE VOTING
     AGREEMENT DATED AS OF FEBRUARY 28, 1999, BETWEEN GILEAD SCIENCES, INC. AND
     ________________,  A COPY OF WHICH IS ON FILE AT THE PRINCIPAL EXECUTIVE
     OFFICES OF GILEAD SCIENCES, INC. 

SECTION 8.     MISCELLANEOUS.

     8.1  SURVIVAL OF REPRESENTATIONS, WARRANTIES AND COVENANTS.  All
representations, warranties, covenants and obligations of Stockholder contained
in this Voting Agreement shall survive the Expiration Date.

     8.2  INDEMNIFICATION.  Stockholder shall hold harmless and indemnify Parent
and Parent's affiliates from and against, and shall compensate and reimburse
Parent and Parent's affiliates for, any loss, damage, claim, liability, fee
(including attorneys' fees), demand, cost or expense (regardless of whether or
not such loss, damage, claim, liability, fee, demand, cost or expense relates to
a third-party claim) that is directly or indirectly suffered or incurred by
Parent or any of Parent's affiliates, or to which Parent or any of Parent's
affiliates otherwise becomes subject, and that arises directly or indirectly
from, or relates directly or indirectly to,  (a) any inaccuracy in or breach of
any representation or warranty contained in this Voting Agreement, or (b) any
failure on the part of Stockholder to observe, perform or abide by, or any other
breach of, any restriction, covenant, obligation or other provision contained in
this Voting Agreement or in the Proxy.

     8.3  INDEPENDENCE OF OBLIGATIONS.  The covenants and obligations of
Stockholder set forth in this Voting Agreement shall be construed as independent
of any other agreement or arrangement between Stockholder, on the one hand, and
the Company or Parent, on the other.  The existence of any claim or cause of
action by Stockholder against the Company or Parent shall not constitute a
defense to the enforcement of any of such covenants or obligations against
Stockholder.

     8.4  SPECIFIC PERFORMANCE. Stockholder agrees that in the event of any
breach or threatened breach by Stockholder of any covenant, obligation or other
provision contained in this Voting Agreement, Parent shall be entitled (in
addition to any other remedy that may be available to Parent) to:  (a) a decree
or order of specific performance or mandamus to enforce the observance and
performance of such covenant, obligation or other provision; and (b) an
injunction restraining such breach or threatened breach.  Stockholder further
agrees that neither Parent nor any other person or entity shall be required to
obtain, furnish or post any bond or similar instrument in connection with or as
a condition to obtaining any remedy referred to in this Section 8.4, and
Stockholder irrevocably waives any right Stockholder may have to require the
obtaining, furnishing or posting of any such bond or similar instrument.


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     8.5  OTHER AGREEMENTS. Nothing in this Voting Agreement shall limit any of
the rights or remedies of Parent under the Merger Agreement, or any of the
rights or remedies of Parent or any of the obligations of Stockholder under any
agreement between Stockholder and Parent or any certificate or instrument
executed on behalf of Stockholder in favor of Parent; and nothing in the Merger
Agreement or in any other agreement, certificate or instrument shall limit any
of the rights or remedies of Parent or any of the obligations of Stockholder
under this Voting Agreement.

     8.6  NOTICES.  Any notice or other communication required or permitted to
be delivered to Stockholder or Parent under this Voting Agreement shall be in
writing and shall be deemed properly delivered, given and received when
delivered to the address or facsimile telephone number set forth beneath the
name of such party below (or to such other address or facsimile telephone number
as such party shall have specified in a written notice given to the other
party):

          IF TO PARENT:  

               Gilead Sciences, Inc
               333 Lakeside Drive
               Foster City, CA 94404
               Attn:  General Counsel
               Fax: (650) 522-5622

          IF TO STOCKHOLDER:

               _____________________________
               _____________________________
               _____________________________
               _____________________________
               _____________________________

     8.7  SEVERABILITY.  If any provision of this Voting Agreement or any part
of any such provision is held under any circumstances to be invalid or
unenforceable in any jurisdiction, then (a) such provision or part thereof
shall, with respect to such circumstances and in such jurisdiction, be deemed
amended to conform to applicable laws so as to be valid and enforceable to the
fullest possible extent, (b) the invalidity or unenforceability of such
provision or part thereof under such circumstances and in such jurisdiction
shall not affect the validity or enforceability of such provision or part
thereof under any other circumstances or in any other jurisdiction, and (c) the
invalidity or unenforceability of such provision or part thereof shall not
affect the validity or enforceability of the remainder of such provision or the
validity or enforceability of any other provision of this Voting Agreement. 
Each provision of this Voting Agreement is separable from every other provision
of this


                                          7


Voting Agreement, and each part of each provision of this Voting Agreement is
separable from every other part of such provision.

     8.8  APPLICABLE LAW; JURISDICTION.   THIS VOTING AGREEMENT IS MADE UNDER,
AND SHALL BE CONSTRUED AND ENFORCED IN ACCORDANCE WITH, THE LAWS OF DELAWARE
APPLICABLE TO AGREEMENTS MADE AND TO BE PERFORMED SOLELY THEREIN, WITHOUT GIVING
EFFECT TO PRINCIPLES OF CONFLICTS OF LAW.  In any action between the parties
hereto, whether arising out of this Voting Agreement or otherwise: (a) each of
the parties irrevocably and unconditionally consents and submits to the
exclusive jurisdiction and venue of the state and federal courts located in the
State of Delaware; (b) if any such action is commenced in a state court, then,
subject to applicable law, no party shall object to the removal of such action
to any federal court located in Delaware; (c) each of the parties irrevocably
waives the right to trial by jury; and (d) each of the parties irrevocably
consents to service of process by first class certified mail, return receipt
requested, postage prepaid, to the address at which such party is to receive
notice in accordance with Section 8.6.

     8.9  WAIVER.  No failure on the part of Parent to exercise any power,
right, privilege or remedy under this Voting Agreement, and no delay on the part
of Parent in exercising any power, right, privilege or remedy under this Voting
Agreement, shall operate as a waiver of such power, right, privilege or remedy;
and no single or partial exercise of any such power, right, privilege or remedy
shall preclude any other or further exercise thereof or of any other power,
right, privilege or remedy.  Parent shall not be deemed to have waived any claim
arising out of this Voting Agreement, or any power, right, privilege or remedy
under this Voting Agreement, unless the waiver of such claim, power, right,
privilege or remedy is expressly set forth in a written instrument duly executed
and delivered on behalf of Parent; and any such waiver shall not be applicable
or have any effect except in the specific instance in which it is given.

     8.10 ATTORNEYS' FEES.  If any legal action or other legal proceeding
relating to this Voting Agreement or the enforcement of any provision of this
Voting Agreement is brought against Stockholder, the prevailing party shall be
entitled to recover reasonable attorneys' fees, costs and disbursements (in
addition to any other relief to which the prevailing party may be entitled).

     8.11 CAPTIONS.  The captions contained in this Voting Agreement are for
convenience of reference only, shall not be deemed to be a part of this Voting
Agreement and shall not be referred to in connection with the construction or
interpretation of this Voting Agreement.

     8.12 FURTHER ASSURANCES.  Stockholder shall execute and/or cause to be
delivered to Parent such instruments and other


                                          8


documents and shall take such other actions as Parent may reasonably request to
effectuate the intent and purposes of this Voting Agreement.

     8.13 ENTIRE AGREEMENT.  This Voting Agreement and any Affilate Agreement or
Registration Rights Agreement between Stockholder and Parent collectively set
forth the entire understanding of Parent and Stockholder relating to the subject
matter hereof and thereof and supersede all other prior agreements and
understandings between Parent and Stockholder relating to the subject matter
hereof and thereof.

     8.14 NON-EXCLUSIVITY.  The rights and remedies of Parent under this Voting
Agreement are not exclusive of or limited by any other rights or remedies which
it may have, whether at law, in equity, by contract or otherwise, all of which
shall be cumulative (and not alternative).  Without limiting the generality of
the foregoing, the rights and remedies of Parent under this Voting Agreement,
and the obligations and liabilities of Stockholder under this Voting Agreement,
are in addition to their respective rights, remedies, obligations and
liabilities under common law requirements and under all applicable statutes,
rules and regulations.  Nothing in this Voting Agreement shall limit any of
Stockholder's obligations, or the rights or remedies of Parent, under any
Affiliate Agreement between Parent and Stockholder; and nothing in any such
Affiliate Agreement shall limit any of Stockholder's obligations, or any of the
rights or remedies of Parent, under this Voting Agreement.

     8.15 AMENDMENTS.  This Voting Agreement may not be amended, modified,
altered or supplemented other than by means of a written instrument duly
executed and delivered on behalf of Parent and Stockholder.

     8.16 ASSIGNMENT; BINDING EFFECT.  Neither this Voting Agreement nor any of
the interests or obligations hereunder may be assigned or delegated by
Stockholder, and any attempted or purported assignment or delegation of any of
such interests or obligations shall be void.  Subject to the preceding sentence,
this Voting Agreement shall be binding upon Stockholder and Stockholder's heirs,
estate, executors, personal representatives, successors and assigns, and shall
inure to the benefit of Parent and its successors and assigns.  Without limiting
any of the restrictions set forth in Section 2 or elsewhere in this Voting
Agreement, this Voting Agreement shall be binding upon any Person to whom any
Subject Securities are Transferred prior to the termination of this Voting
Agreement.  Nothing in this Voting Agreement is intended to confer on any Person
(other than Parent and its successors and assigns) any rights or remedies of any
nature.

     8.17 EXPENSES.  All costs and expenses incurred in connection with the
transactions contemplated by this Voting


                                          9


Agreement shall be paid by the party incurring such costs and expenses.

     8.18 TERMINATION.  

          (a)  This Voting Agreement shall automatically terminate on the
Expiration Date; PROVIDED, HOWEVER, that the termination of this Voting
Agreement shall not relieve Stockholder from any liability for any previous
breach of this Voting Agreement.  

          (b)  If the Parent Share Value (as defined in the Merger Agreement) is
less than the Specified Price (as defined below), then, immediately prior to the
Special Meeting (as defined in the Merger Agreement), (i) Stockholder shall be
entitled to revoke the Proxy, and (ii) Stockholder's obligations under Sections
3.1 and 3.2(a)(ii) shall terminate; PROVIDED, HOWEVER, that (1) the termination
of such obligations shall not relieve Stockholder from any liability for any
previous breach of any of such obligations, and (2) Stockholder's obligations
under Sections 5 and 8 shall remain in full force and effect until this Voting
Agreement is otherwise terminated pursuant to Section 8.18(a).  The Specified
Price shall be $27.00; PROVIDED, HOWEVER, that in the event the outstanding
Parent Shares (as defined in the Merger Agreement shall be changed into a
different number of shares by reason of any stock dividend, subdivision,
reclassification, split-up, combination or the like, the Specified Price shall
be appropriately adjusted.

     8.19 COUNTERPARTS.  This Voting Agreement may be executed by the parties in
separate counterparts, each of which when so executed and delivered shall be an
original, but all of which shall together constitute one and the same
instrument.

     8.20 CONSTRUCTION.

          (a)  For purposes of this Voting Agreement, whenever the context
requires: the singular number shall include the plural, and vice versa; the
masculine gender shall include the feminine and neuter genders; the feminine
gender shall include the masculine and neuter genders; and the neuter gender
shall include masculine and feminine genders.

          (b)  The parties agree that any rule of construction to the effect
that ambiguities are to be resolved against the drafting party shall not be
applied in the construction or interpretation of this Voting Agreement.

          (c)  As used in this Voting Agreement, the words 'include' and
'including,' and variations thereof, shall not be deemed to be terms of
limitation, but rather shall be deemed to be followed by the words 'without
limitation.'


                                          10


          (d)  Except as otherwise indicated, all references in this Voting
Agreement to 'Sections' and 'Exhibits' are intended to refer to Sections of this
Voting Agreement and Exhibits to this Voting Agreement.
























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     IN WITNESS WHEREOF, Parent and Stockholder have caused this Voting
Agreement to be executed as of the date first written above.

                              GILEAD SCIENCES, INC.

                              By:
                                 -------------------------------


                              STOCKHOLDER:
                              
                              ----------------------------------
                              

SHARES HELD                                        ADDITIONAL SECURITIES
 OF RECORD          OPTIONS AND OTHER RIGHTS         BENEFICIALLY OWNED
------------        ------------------------       ----------------------






                                      EXHIBIT A

                              FORM OF IRREVOCABLE PROXY

     The undersigned stockholder of NeXstar Pharmaceuticals, Inc., a Delaware
corporation (the 'Company'), hereby irrevocably (to the fullest extent permitted
by law) appoints and constitutes John C. Martin, Mark L. Perry and Gilead
Sciences, Inc., a Delaware corporation ('Parent'), and each of them, the
attorneys and proxies of the undersigned with full power of substitution and
resubstitution, to the full extent of the undersigned's rights with respect to
(i) the outstanding shares of capital stock of the Company owned of record by
the undersigned as of the date of this proxy, which shares are specified on the
final page of this proxy, and (ii) any and all other shares of capital stock of
the Company which the undersigned may acquire on or after the date hereof.  (The
shares of the capital stock of the Company referred to in clauses '(i)' and
'(ii)' of the immediately preceding sentence are collectively referred to as the
'Shares.')  Upon the execution hereof, all prior proxies given by the
undersigned with respect to any of the Shares are hereby revoked, and the
undersigned agrees that no subsequent proxies will be given with respect to any
of the Shares.

     This proxy is irrevocable, is coupled with an interest, is granted in
connection with the execution and delivery of the Voting Agreement, dated as of
the date hereof, between Parent and the undersigned (the 'Voting Agreement') and
is granted in consideration of Parent entering into the Agreement and Plan of
Merger, dated as of the date hereof, among Parent, Gazelle Acquisition Sub, Inc.
and the Company (the 'Merger Agreement'); PROVIDED, HOWEVER, that the
undersigned may revoke this proxy under the circumstances specified in Section
8.18(b) of the Voting Agreement.  

     The attorneys and proxies named above (and their successors) will be
empowered, and may exercise this proxy, to vote the Shares at any meeting of the
stockholders of the Company, however called, or in connection with any
solicitation of written consents from stockholders of the Company, in favor of
the approval and adoption of the Merger Agreement and the approval of the merger
contemplated thereby, and in favor of each of the other actions contemplated by
the Merger Agreement.  The undersigned may vote the Shares on all other matters.

     This proxy shall be binding upon the heirs, estate, executors, personal
representatives, successors and assigns of the undersigned (including any
transferee of any of the Shares).

If any provision of this proxy or any part of any such provision is held under
any circumstances to be invalid or unenforceable in any jurisdiction, then (a)
such provision or part thereof shall,


                                          1


with respect to such circumstances and in such jurisdiction, be deemed amended
to conform to applicable laws so as to be valid and enforceable to the fullest
possible extent, (b) the invalidity or unenforceability of such provision or
part thereof under such circumstances and in such jurisdiction shall not affect
the validity or enforceability of such provision or part thereof under any other
circumstances or in any other jurisdiction, and (c) the invalidity or
unenforceability of such provision or part thereof shall not affect the validity
or enforceability of the remainder of such provision or the validity or
enforceability of any other provision of this proxy.  Each provision of this
proxy is separable from every other provision of this proxy, and each part of
each provision of this proxy is separable from every other part of such
provision.

     This proxy shall terminate upon the sooner to occur of the valid
termination of the Voting Agreement and the valid revocation of this proxy
pursuant to Section 8.18(b)(i) of the Voting Agreement.

Dated:  February __, 1999


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


                              Number of shares of common stock of the Company
                              owned of record as of the date of this proxy:

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






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