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                                                                Exhibit 10.8



                           LEASE EXTENSION AGREEMENT

This agreement is dated April 15, 1993 for reference purposes and is an
additional modification to the current Lease dated November 30, 1990 between
Charles A. Grant and Mark Greenberg (LESSOR) and Urnotech Calypte Biomedical
Corporation (LESSEE) for the property known as 1440 Fourth Street, Berkeley,
California. 

The Lease is modified by the inclusion of the following additional terms,
hereby agreed between LESSOR and LESSEE:

 1) EXTENSION AND LEASE RATE.  The lease termination date in Paragraph 3.1 is
    changed from the previously extended termination date, to June 30, 1995.
    The rate remains at $14,000 per month through March 1995, and will increase
    to $15,000 per month effective April 1, 1995.

 2) SECURITY DEPOSIT.  The security deposit amount as of this date is $14,800.

 3) LESSEE RESTORATION REQUIREMENTS.  With respect to the Lease Addendum
    Paragraph 50, the alterations, improvements, additions, Utility
    Installations or other modifications made in the Prior Lease for which
    LESSOR may make Written Demand are restricted to the raised-cement-floor
    room, and to the removal of equipment, hoods, cold-rooms, lab benches, and
    other special additions related to laboratory usage of the premises.  With
    respect to any Written Demand, LESSEE will make restorations so as to fully
    repair the affected premises including but not restricted to floors, floor
    covering, walls, utilities, roof and ceiling.

 4) EXTENSION OPTION (1997).  LESSEE is granted an option to extend the Lease
    until June 30, 1997. LESSEE may exercise this option by giving written
    notice to LESSOR on or before February 15, 1995.  The lease rate shall be
    $15,000 per month from July 1995 through March 1997, and will increase to
    $16,000 effective April 1997.

 5) EXTENSION OPTION (1999).  If LESSEE exercises the option in the prior
    paragraph, then LESSEE is granted an option to extend the Lease until June
    30, 1999.  LESSEE may exercise this option by giving written notice to
    LESSOR on or before February 15, 1997.  The lease rate for this period shall
    be $16,000 per month from July 1997 through March 1999, and will increase to
    $17,000 effective April 1999.

SIGNED: /s/ Charles A. Grant             Gen. Partner       4/15/93
        -----------------------------------------------------------
        For LESSOR                          Title              Date

SIGNED: /s/ Paul Siegel                      CFO            4/26/93
        -----------------------------------------------------------
        For LESSEE                          Title              Date

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                                                                           COPY

                        SECOND LEASE EXTENSION AGREEMENT

This agreement is dated May 10, 1991 for reference purposes and modifies the
current Lease dated November 30, 1990 between Charles A. Grant and Mark
Greenberg (LESSOR) and Urnotech Calypte Biomedical Corporation (LESSEE) for the
property known as 1440 Fourth Street, Berkeley, California.

The Lease is modified by the inclusion of an additional term:

        LESSOR AND LESSEE hereby agree that the lease termination date in
        Paragraph 3.1 is changed from April 30, 1991 to September 30, 1991.

Rental for the extended period is due and payable as specified in the lease,
with a payment of $14,000 due on June 1, 1991.

SIGNED: /s/ Mark Greenberg                    5/14/91
        ---------------------------------------------
        LESSOR                                   Date

SIGNED: /s/ D.J. Rafiso for Howard Urnovitz  5/14/91
        ---------------------------------------------
        LESSEE                                   Date

  
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                           LEASE EXTENSION AGREEMENT

This agreement is dated February 5, 1992 for reference purposes and is an
additional modification to the current Lease dated November 30, 1990 between
Charles A. Grant and Mark Greenberg (LESSOR) and Urnotech Calypte Biomedical
Corporation (LESSEE) for the property known as 1440 Fourth Street, Berkeley,
California. 

The Lease is modified by the inclusion of the following additional terms:

 1) LESSOR AND LESSEE hereby agree that the lease termination date in Paragraph
    3.1 is changed from the prior extended termination date to December 31,
    1992, at the present monthly rate of $14,000 per month.

 2) LESSOR AND LESSEE hereby agree that the security deposit is increased by
    $1,000 in consideration of rear fire-door construction to be undertaken and
    paid by LESSEE.

 3) LESSOR AND LESSEE hereby agree that LESSEE is granted an option to further
    extend the lease until June 30, 1993 at the present monthly rate of $14,000.
    LESSEE may exercise this option by giving written notice to LESSOR on or
    before August 15, 1992.  In the event such option is exercised, LESSOR will
    increase the amount of the security deposit by $4,000 in consideration of
    parking lot re-paving and striping to be undertaken and paid by LESSEE.

SIGNED: /s/ Charles A. Grant                   2/5/92
        ---------------------------------------------
        LESSOR                                   Date

SIGNED: /s/ for Calypte Biomedical Corporation 3/3/92
        ---------------------------------------------
        LESSEE                                   Date

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                                                                     EXHIBIT E

                                LEASE ASSIGNMENT

        This LEASE ASSIGNMENT ("Assignment") is entered into as of April __,
1988 by and among California Integrated Diagnostics, Inc., a Delaware
corporation ("CID"), Calypte Biomedical Company ("Calypte"), a joint venture
organized under Connecticut law between Calypte, Inc., a Delaware corporation,
and Purdue Frederick Diagnostics, Inc., a Delaware corporation, The Purdue
Frederick Company, a New York corporation ("Purdue"), and Charles A. Grant and
Mark L. Greenberg (together, "Lessors").

                                    RECITALS

        On September 25, 1981, Lessors entered into a lease with Hytech
Sciences, Inc., a California corporation ("Hytech"), for certain office and
laboratory space located at 1440 Fourth Street, Berkeley, California and more
fully described in Exhibit A (the "Site").  Hytech subsequently assigned all of
its right, title and interest in the lease to CID and on August 5, 1986, CID
(then called Integrated Diagnostics, Inc.) entered into a Lease Renewal with
Lessors whereby the original lease was extended for five years.  On May 15,
1987, Lessors, CID and its parent, The InFerGene Company entered into a Consent
to Sublease and Lease Modification Agreement (the "Consent") which provided
for, among other things, the modification of the Lease Renewal.  The original
lease, the Lease Renewal and the Consent, copies of which are attached as
Exhibit A, are referred to herein collectively as the "Lease."  Concurrently
herewith, CID and Calypte are entering into an Assets Purchase and Lease
Assignment Agreement (the "Agreement") whereby CID will sell certain trade
fixtures, equipment and other property located at the Site to Calypte and
Calypte will take over possession of the Site from CID.  Calypte wishes to
obtain an assignment of all of CID's right, title and interest in the Lease and
Lessors have consented to such assignment on the terms and conditions set forth
below. 

        1.  Assignment.  For valuable consideration described in the Agreement,
CID hereby grants, conveys and assigns to Calypte all of CID's right, title and
interest in and to (i) the Lease, (ii) all leasehold improvements located at
the Site, including but not limited to all permanently installed:  carpets,
plumbing, electrical work, sinks, stairs, handrails, decks, floor tiles and
sprinklers (the "Leasehold Improvements"), (iii) all trade fixtures located at
the Site, including but not limited to removable:  laboratory benches
(including sinks), cabinets, shelves, walk in cold rooms and 
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freezers, fume hoods, partitions and work stations ("Trade Fixtures") and (iv)
the security deposit in the amount of $15,600 ("Security Deposit") currently
held by Lessors under the Lease.  Calypte hereby agrees to become the assignee
of the Lease, to substitute itself as lessee under the Lease and to be bound by
all of the terms, covenants, conditions and agreements contained in the Lease.
Calypte acknowledges that (i) it is taking possession of the Site "as is," (ii)
the Site is suitable for use by Calypte, and (iii) neither CID nor its agents
have made any representations or warranties as to the suitability or condition
of the Site.

        2.  Lessors Consent.  Lessors hereby consent to the assignment of all
of CID's right, title and interest in the Lease, the Leasehold Improvements,
Trade Fixtures and the Security Deposit to Calypte.  Lessors agree that upon
their execution of this Assignment CID shall be released from any obligation to
Lessors under the Lease and Lessors shall look solely to Calypte and Purdue for
the performance of the terms of the Lease.  Lessors acknowledge that (i) the
Lease is in full force and effect on the date hereof, including the option to
extend the Lease, (ii) on the date hereof CID does not owe any amount to
Lessors under the Lease or otherwise, (iii) Lessors are currently holding the
Security Deposit, (iv) CID is not in default under the Lease, (v) the Site is
in satisfactory condition for use by Calypte, (vi) any cracking in the exterior
walls or foundation of the Site are a result of reasonable use and wear or
damage by the elements and Calypte upon surrender of the Site at the expiration
of the Lease term or any extension thereof shall not be liable for the repair
thereof, (vii) Lessors claim no right, title or interest to the Trade Fixtures,
and (viii) Calypte shall have the right to remove the Trade Fixtures at the
expiration of the Lease term or any extension thereof subject to its obligation
under the Lease to repair any damage to the Site caused by Calypte's removal of
the Trade Fixtures.  Lessors consent to the Sublease Assignment attached hereto
as Exhibit B.

        3.  Guarantee.  Purdue agrees to guarantee the performance by Calypte
of all of its obligations under the Lease.

        4.  Damage Repair.  Damage done to the Site as a result of any use
which is particular to Calypte's business such as, but not limited to the use
of chemical, biological or radioactive substances shall not be considered
normal wear and tear and shall be repaired at Calypte's expense at the
termination of the Lease or any extension thereof.

        5.  Miscellaneous.  This Assignment shall be governed by the laws of
the State of California.  This 

                                       2

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Assignment may be signed in any number of counterparts, each of which shall be
an original, and all of which, when taken together, shall constitute one
agreement. 

        IN WITNESS WHEREOF, this Lease Assignment is entered into as of the
date first written above.

                                CALIFORNIA INTEGRATED DIAGNOSTICS, INC.

                                By
                                  -------------------------------------------
                                        Bernard DiDario, President

                                CALYPTE BIOMEDICAL COMPANY
                                        By CALYPTE, INC.

                                        By
                                          -----------------------------------
                                             Title:

                                        By PURDUE FREDERICK DIAGNOSTICS, INC.
     
                                        By
                                        --------------------------------------
                                        Title:

                                THE PURDUE FREDERICK COMPANY

                                By
                                  -------------------------------------------
                                     Title:


                                LESSORS:


                                ---------------------------------------------
                                          Charles A. Grant


                                ---------------------------------------------
                                          Mark L. Greenberg
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                                   Exhibit A

                               [RAIKE LETTERHEAD]

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

Parties   This Lease, executed in duplicate this 25th day of September 1981 by
          and between CHARLES A. GRANT and MARK L. GREENBERG

          and HYTECH SCIENCES INCORPORATED, a California corporation,

          hereinafter called respectively Lessor and Lessee, without regard to
          number or gender,

Use               WITNESSETH: That Lessor hereby leases to Lessee, and Lessee
          hires from Lessor, for the purpose of conducting therein RESEARCH,
          development, manufacturing and warehousing of medical, biological and
          related products. and for no other purpose, without the written
          consent of Lessor first had and obtained those certain premises with
Premises  the appurtenances thereto, situated in State of California, and those
          particularly described as follows, to wit:

          Alameda County Assessor's parcel Numbers: 59-2324-1-1 and 59-2324-11
          as shown in red on Exhibit A, commonly known as 1440 Fourth Street,
          Berkeley, California.


 Term             The term shall be for Five (5) years, commencing on the First
          day of December 1981, and ending on the Thirtieth (30) day of November
          1986, at a rental payable in lawful money of the United States of
          America, which Lessee agrees to pay to Lessor, without deduction or
          offset at 14440 Catalina Street, San Leandro or such place or places
          as may be designated in writing from time to time by Lessor, in
          advance, in installments as follows:

          The sum of Seven Thousand Eight Hundred and no/100 ($7,800.00) Dollars
          receipt of which is hereby acknowledged; the further sum of Seven
          Thousand Eight Hundred and no/100 ($7,800.00) on the first day of
          January 1982, and a like sum of Seven Thousand Eight Hundred and
          no/100 ($7,800.00) on the first day of each and every succeeding
          month up to and including the first day of May 1984. THE 
          ABOVE RENTAL PAYMENT SHALL BE ADJUSTED AT THE BEGINNING OF THE 
          THIRTIETH (30th) MONTH PER PARAGRAPH 131.

          It is further mutually agreed between the parties as follows:

Security          1. Lessor acknowledges receipt from Lessee of the sum of
          Fifteen Thousand Six Hundred Dollars ($15,600.00) as security for the
          full and faithful performance of Lessee's obligations hereunder. In
          the event Lessee is not in default sixty (60) days prior to the
          termination of the herein lease term, Lessor shall return said sum to
          Lessee, or if this lease be sooner terminated for reason other than
          default on behalf of Lessee, said sum shall be likewise refunded. See
          Paragraph 30.

Delivery          2. In the event of the inability of Lessor, for any reason
   of     whatsoever, to deliver possession of the premises at the time of the
Posses-   commencement of the term of this lease, neither Lessor nor Damon Raike
  sion    & Co. shall be liable for any damage caused thereby, nor shall this
          lease thereby become void or voidable, nor shall the term herein
          specified be in any way extended, but in the event there shall be no
          rental payable for the period between the commencement of the said
          term and the time when Lessor can deliver possession.
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[COPY TO COME]
               the purpose or purposes for which the said premises are hereby
               leased; and no use shall be made or permitted to be made of the
               said premises, nor acts done, which will increase the existing
               rate of insurance upon the building in which said premises may
               be located, or cause a cancellation of any insurance policy
               covering said building, or any part thereof, nor shall Lessee
               sell, or permit to be kept, used, or sold, in or about said
               premises, any articles which may be prohibited by the term of
               fire insurance policies. Lessee shall, at his sole cost and
               expense, comply with any and all requirements of any insurance
               organization or company pertaining to said premises, which
               requirements are necessary for the maintenance of reasonable fire
               and public liability insurance, covering said building and
               appurtenances. See Paragraph 26.

                       Lessee shall not commit, or suffer to be committed, any
               waste upon said premises, or any nuisance, or other act or thing
               which may disturb the quiet enjoyment of any other tenant in the
               building in which the demised premises may be located, or in any
               way obstruct, interfere with, injure or annoy them, or do or
               permit to be done anything in any way tending to disturb the
               occupants of neighboring property or tending to injure the
               reputation or appearance of the building.

                       Lessee shall not conduct or permit to be conducted any
               sale by auction on or from said premises.

Alterations            4. Lessee shall not make, or suffer to be made, any
               alterations of the said premises, or any part thereof, without
               the written consent of Lessor first had and obtained, and any
               additions to, or alterations of, the said premises, except
               movable furniture and trade fixtures, shall become at once a part
               of the realty and belong to Lessor.

Abandon-               5. Lessee shall not vacate or abandon the premises at any
 ment          time during the term; and if Lessee shall abandon, vacate or
               surrender said premises, or be dispossessed by process of law, or
               otherwise, any personal property belonging to Lessee and left on
               the premises shall, at the option of Lessor, be deemed to be
               abandoned.

                       6. Lessee shall, at his sole cost, keep and maintain said
               premises and appurtenances and every part thereof (including
               exterior walls and roofs which Lessee agrees to repair),
               including, without limitation, glazing, sidewalks adjacent to
               said premises, plumbing, heating and sewer facilities, any store
               front, and the interior of the premises, in good and sanitary
               order, condition and repair, hereby waiving all right to make
               repairs at the expense of Lessor. By entry hereunder, Lessee
               accepts the premises as being in good and sanitary order,
               condition and repair, and agrees on the last day of said term, or
               sooner ????? of this lease, to surrender unto Lessor all and
               singular said premises and the appurtenances in the same
               condition as when received, reasonable use and wear thereof and
               damage by fire, act of God or by the elements excepted, and to
               remove all of Lessee's signs from said premises. See Paragraph
               29.

                       Lessee shall have all passenger and/or freight elevators
               now on or hereafter constructed upon the premises, and all
               elevators, including sidewalk elevators, actually used by Lessee
               in connection with the premises, whether on the premises or not,
               regularly inspected, and shall keep the same in good running
               order and in perfect repair and condition and keep same covered
               during the term hereof by permit and license to operate by the
               Industrial Accident Commission of the State of California, and by
               any other public authority from which a license or permit is or
               may be required, at the sole cost and expense of Lessee.

                       In the event that the provisions of any law, ordinance,
               or rule now in force or hereafter enacted by Municipal, State, or
               National Authority, requires, by reason of Lessee's use of the
               premises, any alterations, additions, repairs or acts of any kind
               to be done in connection with the premises or any part thereof,
               the same shall be done at the sole cost and expense of Lessee.

Free from              7. Lessee shall keep the demised premises and the
 Liens         property on which the demised premises are located, free from any
               liens arising out of any work performed, materials furnished, or
               obligations incurred by Lessee.

Compliance             8. Lessee shall, at his sole cost and expense, comply
with           with all of the requirements of all Municipal, State, and Federal
Govern-        Authorities now in force, or which may hereafter be in force,
mental         pertaining to the use of said premises, and shall faithfully
Regulations    observe in the use of the premises all Municipal ordinances and
               State and Federal Statutes now in force or which may hereafter be
               in force. The judgment of any court of competent jurisdiction, or
               the admission of Lessee in any action or proceeding against
               Lessee, whether Lessor be a party thereto or not, that Lessee has
               violated any such ordinance or statute in the use of the
               premises, shall be conclusive of that fact between Lessor and
               Lessee.

Hold                   9. Lessee, as a material part of the consideration to be
Harmless       rendered to Lessor, hereby waives all claims against Lessor for
               damages to goods, wares and merchandise, and all other personal
               property in, upon or about said premises and for injuries to
               persons in or about said premises, from any cause arising at any
               time, and Lessee will save, defend, and hold Lessor exempt and
               harmless from any damage or injury, occurring in, on, or about
               the demised premises, to any person, or to the goods, wares and
               merchandise and all other personal property of any person arising
               from any cause whatsoever.

Advertise-             10. Lessor reserves the exclusive right to the roof, and
ments          to all exterior walls or parts of the premises, and access
and            thereto, and the same are not covered by this lease, and Lessee
Signs          agrees that no signs, advertisements or notices whatsoever shall
               be inscribed, painted, affixed or displayed on, to or in any part
               of the outside or inside, or on the roof of the premises, without
               the written consent of Lessor. Any signs to placed on the
               premises shall be so placed upon the understanding and agreement
               that Lessee will remove same at the termination of the tenancy
               herein created and repair any damage or injury to the premises
               caused thereby, and if not so removed by Lessee then Lessor may
               have same so removed at Lessee's expense.

Utilities              11. Lessee shall pay promptly, as the same may become
               due, all bills for water, gas, heat, light, power, telephone
               service and all other services supplied to the said premises.

Entry by               12. Lessee shall permit Lessor and/or his agents to enter
Lessor         into and upon said premises at all reasonable times for the
               purpose of inspecting the same or for the purpose of maintaining
               the building in which said premises are situated, or for the
               purpose of making repairs, alterations or additions to any
               portion of said building, including the erection and maintenance
               of such scaffolding, canopies, fences and props as may be
               required, or for the purpose of posting notices of
               nonresponsibility, or for the purpose of placing upon the
               property in which the said premises are located any usual or
               ordinary "for sale" signs, without any rebate of rent and without
               any liability to Lessee for any loss of occupancy or quiet
               enjoyment of the premises thereby occasioned, and shall permit
               Lessor and his agents, at any time within ninety days prior to
               the expiration of this lease, to place upon said premises any
               usual or ordinary "to let" or "to lease" signs and to exhibit the
               premises to prospective tenants at reasonable hours.

Destruction            13. In the event of a partial destruction of the premises
of Premises    during the said term, from any cause, other than ordinary wear
               and tear, Lessor shall forthwith repair the same, provided such
               repairs can be made within ninety (90) days under the then
               existing laws and regulations. Such partial destruction shall in
               no wise annul or void this lease, except that the Lessee shall be
               entitled to a proportionate reduction of rent while such repairs
               are being made, such reduction to be based upon the extent to
               which the making of such repairs shall interfere with the
               business carried on by the Lessee in the said premises. If such
               repairs cannot be made within ninety (90) days, Lessor may, at
               his option, make same within a reasonable time, this lease
               continuing in full force and effect and the rent to be
               proportionately reduced as aforesaid. In the event that Lessor
               shall elect not to make such repairs which cannot be made within
               ninety (90) days, Lessor shall give Lessee prompt written notice
               of such election, and thereupon this lease may be terminated at
               the option of either party by notice in writing to the other
               within five (5) days after the giving or receiving of such
               notice. In respect to any partial destruction which Lessor is
               obligated to repair or may elect to repair under the terms of
               this paragraph, the Provisions of Section 1932, Subdivision 2,
               and of Section 1933, Subdivision 4, of the Civil Code of the
               State of California are waived hereby by Lessee. In the event
               that the building in which the demised premises are situated be
               destroyed to the extent of not less than 33 1/3% of the
               replacement cost thereof, Lessor may elect to terminate this
               lease, whether the demised premises be injured or not. A total
               destruction of the premises,
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               and Lessee relative to the provisions of this paragraph, they
               shall each  [COPY TO COME]  select a third arbitrator, and
               the three arbitrators so selected shall hear and determine the
               controversy, and their decision thereon shall be final and
               binding upon both Lessor and Lessee, who shall bear the cost of
               such arbitration equally between them.

Assignment             14.     Lessee shall not assign this lease, or any
and Subletting interest therein, and shall not sublet the said premises or any
               part thereof, or any right or privilege appurtenant thereto, or
               permit or suffer any other person (the agents and servants of
               Lessee excepted) to occupy or use the said premises, or any
               portion thereof, without the written consent of Lessor first had
               and obtained, which consent shall not be unreasonably withheld,
               and a consent to one assignment, subletting, occupation or use by
               any other person, shall not be deemed to be a consent to any
               subsequent assignment, subletting, occupation or use by another
               person. Any such assignment, subletting, occupation or use
               without such consent shall be void, and shall at the option of
               Lessor, terminate this lease.

Involvency             15.     The appointment of a receiver (except a receiver
or Bankruptcy  contemplated by paragraph 19 hereof) to take possession of all or
               substantially all of the assets of Lessee or of the operations of
               Lessee in the demised premises, or a general assignment by Lessee
               for the benefit of creditors, or the filing of proceedings in
               insolvency or bankruptcy by or against Lessee shall at the option
               of Lessor constitute a repudiation of this lease by Lessee, such
               option to be exercised by Lessor within thirty (30) days from
               receipt of actual notice of any of the aforesaid events, and
               should such option be exercised, Lessee shall forthwith pay to
               Lessor the amount, if any, by which the remainder of the rent
               reserved hereunder exceeds the then reasonable value of the
               remainder of the term of this lease.

Default                16.     In the event of any breach of this lease by
               Lessee, the Lessor shall have, in addition to any other rights or
               remedies, those rights and remedies provided by Section 1951.2
               and Section 1951.4 of the Civil Code of the State of California.
               This lease shall not terminate, even though Lessee has breached
               this lease and abandoned the property, unless Lessor notifies
               Lessee in writing that this lease and Lessee's right of
               possession are terminated.

                       Any breach of the agreements and covenants in this lease
               shall be a default under this lease and shall give Lessor the
               rights and remedies set forth in this paragraph. In addition, the
               following acts or occurrences shall constitute a default under
               this lease and give Lessor the rights set forth in this
               paragraph. If Lessee, or if Lessee be a partnership, then if
               Lessee or any member of such partnership shall file any petition
               or institute any proceeding under the bankruptcy act, either as
               such act now exists or under any amendment thereof which may
               hereafter be enacted, or under any other act or acts, state or
               federal, dealing with or relating to the subject or subjects of
               bankruptcy or insolvency, or under any such amendment of any such
               act or acts, either as a bankrupt, or as an insolvent, or as a
               debtor, or in any similar capacity, or if any such petition or
               any such proceeding of the same or similar kind or character be
               filed or be instituted or taken against Lessee, or if Lessee be a
               partnership, against Lessee or any member of the partnership, or
               if any receiver of the business or of the property or assets of
               the Lessee shall be appointed by any court except a receiver
               appointed at the instance or request of Lessor, or if the Lessee
               shall make a general or any assignment for the benefit of his
               creditors, or if the Lessee shall abandon or vacate the premises,
               or if the Lessee shall otherwise, in any manner whatever, become
               unable to pay the rent herein specified or to perform any of the
               terms, covenants or conditions herein by him to be kept or
               performed.

                       Unless the aforementioned election to terminate is made
               by Lessor, the Lessor shall retain all rights and remedies under
               the lease, including the right to recover rent as it may become
               due under the lease and Lessee shall be liable for all attorneys'
               fees and costs incurred by Lessor by reason of Lessee's breach.
               In no event shall the following actions by Lessor or its agents,
               either before or after any abandonment of the premises by Lessee,
               constitute a termination of this lease:

                       1.  Acts of maintenance or preservation or efforts to
                           relet the property. 

                       2.  Appointment of a receiver upon initiative of the
                           Lessor to protect Lessor's interests under the lease.

                       3.  The consenting to any subletting of the premises or
                           assignment of this lease by Lessee pursuant to
                           Paragraph 14.

                       4.  The removal from the premises of any or all
                           equipment, fixtures and personal property thereon or
                           therein in order to facilitate the reletting of the
                           premises.

                       Upon termination of this lease, Lessor shall have,
               without liability to Lessee, the immediate right to reenter the
               premises, remove all persons and properties therefrom and to
               place such properties in storage for the account of and at the
               expense of Lessee. Upon such removal, Lessor shall notify Lessee
               that such property has been placed in storage and that in the
               event that Lessee does not pay the cost of storing such property.
               Lessor may sell any or all of such property, at private or public
               sale, at any time the storage charges are ninety days delinquent.
               Such sale may be in such manner and at such times and places as
               Lessor, in his sole discretion, may deem proper without notice to
               Lessee or any demand upon Lessee for the payment of any part of
               such charges or the removal of any such property and shall apply
               the proceeds of such sale first, to the cost and expenses of such
               sale, including reasonable attorneys' fees actually incurred;
               second, to the payment of the costs of or charges for storing any
               such property; third, to the payment of any other sums of money
               which may be then or thereafter due to the Lessor from the Lessee
               under the terms of this lease; fourth, the balance, if any, to
               Lessee.

                       If Lessor terminates this lease, Lessee shall pay to
               Lessor and be liable for:

                       1.  All rents and other charges due and unpaid at the
                           time of termination, together with interest thereon
                           accrued from the date each such sum became due at the
                           rate of ten per cent (10%) per annum; and

                       2.  All rents and other charges which become due between
                           the time of termination and the time of award (as
                           hereinafter defined), less any rents and other
                           charges that Lessee proves: (i) Lessor has actually
                           received from reletting the premises, or (ii) Lessor
                           could have obtained in reletting the premises by
                           acting reasonably in the circumstances then
                           prevailing, together with interest thereon accrued
                           from the date each such sum becomes due at the rate
                           of ten per cent (10%) per annum; and

                       3.  The difference, if any, between (A) all rents and
                           other charges for the balance of the term of this
                           lease, and (B) any rents and other charges that
                           Lessee proves: (i) Lessor will receive by reason of
                           the reletting of the premises, or (ii) Lessor could
                           obtain in reletting the premises by acting reasonably
                           in the circumstances then prevailing, which
                           difference shall be discounted to present value at
                           the time of award at the discount rate of the Federal
                           Reserve Bank of San Francisco in effect at the time
                           of award plus one per cent (1%); and

                       4.  All costs, expenses and losses Lessor incurs by
                           reason of Lessee's breach of this lease, including,
                           without limitation, the following: (i) all expenses
                           for repairing or restoring the premises, (ii) all
                           expenses for altering, remodeling, or otherwise
                           improving the premises for the purposes of reletting,
                           (iii) all brokers' fees, advertising costs and other
                           expenses of reletting the premises, (iv) all expenses
                           in retaking possession of the premises, and (v)
                           reasonable attorneys' fees and court costs; and

                       5.  As used in subparagraph B hereof, the term "time of
                           award" shall mean the time of entry of a judgment or
                           award against Lessee in an action or proceeding
                           arising out of Lessee's breach of this lease.

                       Notwithstanding that Lessor elects, after a breach of
               this lease by Lessee, to continue this lease in full force and
               effect, Lessor may at any time thereafter elect to terminate this
               lease for such breach or any other breach.

                       Lessee hereby waives all claims for damages that may be
               caused by Lessor's re-entering and taking possession of the
               premises or removing and storing furniture and property, as
               herein provided, and will save Lessor harmless from loss, costs
               or damages occasioned Lessor thereby, and no such re-entry shall
               be considered or construed to be a forcible entry as therein is
               defined in the Code of Civil Procedure of the State of
               California.

                       The rights, privileges, elections and remedies of Lessor
               in this Paragraph 16 are cumulative and not alternative.

                                      
   10
Surrender               17. The voluntary or other surrender of this lease by
of Lease        Lessee, or a mutual cancellation thereof, shall not work a 
                merger, and shall, at the option of Lessor, terminate all or
                any existing subleases, or subtenancies, or may, at the option 
                of Lessor, operate as an assignment to him of any or all such
                subleases or subtenancies.

Attorney's              18. In case either party shall bring suit, 
Fee             declaratory or otherwise, to enforce or interpret the terms of
                this lease, the prevailing party shall be entitled to a 
                reasonable attorney's fee which shall be determined by the court
                and taxed as part of the cost of such action.

Receiver on             19. If a receiver be appointed at the instance of the
Behalf of       Lessor in any action arising under this lease, or otherwise, 
Lessor          to take possession of said premises and/or to collect the rents
                and profits derived therefrom, the receiver may, if it be
                necessary or convenient in order to collect such rents and
                profits, conduct the business of the Lessee then being carried
                on in said premises, and may take possession of any personal
                property belonging to the Lessee and used in the conduct of
                such business, and may use the same in conducting such business
                on the premises, without compensation to the Lessee for such 
                use. Neither the application for the appointment of a receiver
                nor the appointment of a receiver shall be construed as an
                election on Lessor's part to terminate this lease unless a 
                written notice of such intention is given to the Lessee.

Notices                 20. All notices to be given to Lessee may be given in
                writing personally or by depositing the same in the United
                States mail, postage prepaid, and addressed to Lessee at the
                said premises, whether or not Lessee has departed from, 
                abandoned or vacated the premises.

Waiver                  21. The waiver by Lessor of any breach of any term,
                covenant or condition herein contained shall not be deemed to
                be a waiver of such term, covenant or condition or any
                subsequent breach of the same or any other term, covenant or
                condition herein contained. The subsequent acceptance of rent
                hereunder by Lessor shall not be deemed to be a waiver of any
                preceding breach by Lessee of any term, covenant or condition 
                of this lease, other than the failure of Lessee to pay the 
                particular rental so accepted, regardless of Lessor's
                knowledge of such preceding breach at the time of acceptance
                of such rent.

Holding Over            22. Any holding over after the expiration of the said
                term, with the consent of the Lessor, shall be construed to
                be a tenancy from month to month, and shall otherwise
                be on the terms and conditions herein specified, so far
                as applicable.

Successors              23. The covenants and conditions herein contained shall,
and Assigns     subject to the provisions as to assignment, apply to and bind
                the heirs, successors, executors, administrators and assigns
                of all of the parties hereto; and all of the parties hereto
                shall be jointly and severally liable hereunder.

Time                    24. Time is of the essence of this lease.

Marginal                25. The marginal captions of this Lease are for
Captions        convenience only and shall not be deemed in any manner 
                construe or interpret the terms and provisions hereof.

                Paragraphs 26 through 41 are attached and made a part hereof.





        IN WITNESS WHEREOF, Lessor and Lessee have executed these presents,
the date and year first above written.

LESSOR                                  LESSEE

/s/                                     /s/
-------------------------------         -------------------------------------
/s/                                   
-------------------------------         -------------------------------------
                                        
-------------------------------         -------------------------------------
        
                
   11
                                    Addendum
                                    --------

26. As part of the rent provided for hereinabove, Lessee shall pay on demand any
increase in the premium for insurance of the building, including fire insurance
and extended coverage that may be imposed as a consequence of Lessee's use of
occupation  [COPY TO COME]  of the premises during the term of this lease. In
determining whether increased premiums are the result of the Lessee's use of the
leased premiums, a schedule, issued by the organization making the insurance
rate on the leased premises, showing the various components of such rate, shall
be conclusive evidence of the items and charges which make up the fire insurance
rate of the leased premises.

27. Lessee and Lessor each hereby waive any and all rights of recovery against
the other or against the officers, employees, agents, and representatives of
the other for loss of or damage to property or the property of others under its
control where such loss or damage is insured against under any insurance in
force at the time of such loss or damage. Lessor and Lessee shall on obtaining
the policies of insurance required hereunder give notice to the insurance
carrier or carriers that the foregoing mutual waiver of subrogation is
contained in this lease.

28. Lessee shall, at Lessee's expense, obtain and keep in force during the term
of this lease comprehensive general liability insurance with a combined single
limit of not less than $500,000 per occurrence against liability resulting from
bodily injury and property damage. Lessee shall furnish Lessor with a
certificate of insurance with provisions for thirty (30) days advance written
notice to Lessor of any modification or change in such insurance. Said policy
or policies of insurance shall name Lessor as additional insured  but only with
respect to performance of this agreement. This provision, however, shall not
apply with respect to negligence of Lessor, its officers, agents or employees.
   12
29. Damage done to the subject property as a result of any use which is
particular to Lessee's business such as, but not limited to the use of chemical
or radioactive substances shall not be considered normal wear and tear.

30.     Lessor shall pay to Lessee on the following dates:
        March 1,
        June 1,
        September 1,
        December 1,
of each year during the term of this lease the sum of Two Hundred Fifteen
Dollars and ninety-six cents ($215.96) which represents 5.5% passbook interest
on the amount of the security deposit in paragraph 1. Said payments shall
continue as long as Lessor retains the security deposit.

31.     The monthly rental of $7,800.00 to be paid by Lessee hereunder shall be
adjusted as herein provided commencing with the rental due June 1, 1984, and
continuing thereafter on the first day of each and every month to and including
November 1, 1986:
        On June 1, 1984, the most recently issued official Consumer Price Index
for Urban Wage Earners & Clerical Workers (all items 1967 Base) of the Bureau
of Labor Statistics, U.S. Department of Labor, for the San Francisco Area (as
revised in 1978) shall be examined. If the then most recently issued Consumer
Price Index shall have increased above the Consumer Price Index covering the
first full month that rental payments have been paid as set forth above, then
the monthly rental shall be increased by one-half of the same percentage as the
percentage by which the most recent Consumer Price Index shall have increased
over the Index covering the first full month or any subsequent option terms. 
In no event shall the monthly rental be decreased.
   13

32.  Lessee shall be granted options to renew this lease for two further
periods of five (5) years each from and after expiration of the original term,
under the same terms and conditions except the rental for each five-year
renewal option shall be adjusted at the beginning of each option term in
accordance with increases in the Consumer Price Index for Urban Wage Earners
and Clerical Workers as published by the Bureau of Labor Statistics, all items
(1967=100 as revised) for the San Francisco-Oakland area. Written notice of
Lessee's intention to renew this lease shall be given to Lessor at least one
hundred twenty (120) days prior to the expiration of this lease and expiration
of the first option term. If Lessee does not exercise the first five-year
option, all rights to the second term shall terminate. The rent shall be
increased in proportion to the increase in the Consumer Price Index between the
last monthly index published immediately preceding the commencement of the
original lease term to the last monthly index published immediately preceding
the commencement of the option term. In no event shall the base monthly rental
be reduced below the then current rental. In no event shall the rental be
increased more than 147% of the then current rental.

        In the event the foregoing option is exercised, Lessor, its successor
or assigns agree to pay to Damon Raike and Company, immediately upon exercise
of said option the commission as set forth in the Damon Raike and Company
commission schedule which was signed and amended on September 2, 1981.

        In the event the foregoing options are exercised the rental shall be
adjusted in an identical manner to paragraph 31 on June 1, 1989 and June 1,
1994, respectively.

33.  Lessor shall not sell the property of which the demised premises are a
part, or any portion of said property, or the building in which the demised
premises are contained, without first having given Lessee the opportunity to
purchase the same. If Lessor has received a bona fide offer, there shall be
given to Lessee written notice of said offer which shall state the price and
terms of payments acceptable to Lessor. The price offered to Lessee, less the
commission to Damon Raike and


   14

Company, shall equal the price on the bona fide written offer less the
commissions to be paid by seller. Lessee shall have thirty (30) days within
which to elect in writing whether to purchase at the price and on the terms and
conditions contained in said offer. If Lessee so elects, payment shall be
pursuant to said terms and conditions; but if Lessee does not so elect, Lessor
shall, for a period of 180 days, be free to sell elsewhere, provided that said
sale shall not be at a price or on terms and conditions more favorable to the
purchaser than were contained in the written notice referred to above without
Lessor's first reoffering the property to Lessee pursuant to this paragraph. If
Lessor desires to sell, but has not received a written offer, he shall not sell
said property without receiving such a written offer from any prospective
purchaser and complying with the provisions of this paragraph. In the event
Lessee exercises his rights herein, Lessor, its successors or assigns, agrees
to pay Damon Raike and Company, upon the consummation of sale, the commission
as set forth in the Damon Raike and Company commission schedule which was sign
and amended on September 2, 1981, less the unearned leasing commission which
shall be credited and applied to the sale commission.

   15

35.  If Lessor shall lease or sell to any other company, individual, or
corporation Parcel 14 on Exhibit "A", then Lessee can, at his option, require
Lessor to install a 6' chain link fence along the line as shown in Blue on
Exhibit "A" for security purposes. Lessee's request to install said fence shall
not be unreasonably made.

36.  Lessor agrees to give Lessee permission to make alterations to the demised
premises to make the same suitable for the conduct of Lessee's business, a
bio-medical laboratory, provided that all such alterations shall be done in a
good, safe, workmanlike manner, shall comply with all laws, statutes,
ordinances, and applicable governmental regulations, and shall not in any way
weaken or impair any structural portions of the demised premises. Before
proceeding with any alterations, Lessee shall submit to Lessor for Lessor's
approval, plans and specifications of the planned alterations, Lessor agreeing
it will not unreasonably withhold its approval. Lessee shall advise Lessor in
writing not less than ten (10) days prior to commencement of the making of any
alterations in order to permit Lessor to post a Notice of Non-Responsibility
for any work to be performed by Lessee. All of said alterations shall be made
at the sole cost and expense of Lessee.



   16
        Lessor reserves the right to require Lessee, at the expiration or other
termination of the lease term, to leave in place or to remove, at Lessee's
expense, any or all such of any alterations made, and Lessee shall be
responsible for the repair damage to the demised premises caused by Lessee's
removal of the alterations. Lessee's obligation to perform this covenant shall
survive the expiration or other termination of the term of this lease;
excepting only that in the event Lessee shall exercise its option to purchase
the demised premises the provisions of this Paragraph pertaining to the removal
of alterations shall be of no force or effect.

37.     Lessee's obligation under this Lease Agreement is subject to the
        following conditions:

        1.      Receipt of plans and cost estimates at Lessee's sole cost
                and expense, for the conversion of the demised premises
                to a laboratory, which show that the total cost will not
                exceed $150,000.00.

        2.      Receipt of a report at Lessee's sole cost and expense as
                to the condition of the property including the roof and 
                sidewalls.

        If the cost estimates show that the improvement costs to Lessee are
more than the above amount, or if the condition of the property is not
satisfactory to Lessee, then Lessee can, at his option, cancel this Agreement
by giving notice to Lessor on or before thirty (30) days from the date of
acceptance, and unless such notice is given, the above condition shall be
deemed satisfied. If so cancelled, this Agreement shall be null and void and of
no further effect, and the Lessor agrees to promptly refund any monies paid
herewith by Lessee, and the rights and obligations of each of the parties
hereunder will immediately cease.
   17
38.  Lessee shall immediately apply to the proper governmental authorities for
a ruling to determine whether the premises can be used for a bio-medical
laboratory, and for permission to alter the premises to make them suitable for
said use. In the event Lessee is prohibited from using the premises, in whole
or in part, for the purposes set forth above, by reason of any action of the
planning commission, board of supervisors, board of permit appeals, or any
other governmental agency or division empowered to enact or enforce zoning or
other use, regulations or laws, or permission is withheld to make alterations
to the premises for the purposes of making the premises suitable for the above
use, then Lessee shall notify Lessor, in writing, of such fact, on or before
December 1, 1981. In the event Lessee gives Lessor notification within the
above time, then this lease shall become null and void and of no further force
or effect, and all monies paid by Lessee will immediately be returned to
Lessee. Lessee agrees to give Lessor written notice of his inability to arrange
for the foregoing, by no later than November 15, 1981. In the event of the
failure on the part of said Lessee to do so, then this lease shall be and
remain in full force and effect for its entire term.

39. Lessee has the right to enter upon and occupy the premises more commonly
known as 1440 Fourth Street, Berkeley, California, commencing October 1, 1981,
without payment of additional rent, provided, however, upon said entry he shall
be bound by all terms, conditions, covenants, and agreements contained in the
foregoing Lease, as if said Lease commenced on date of entry.
   18
40.  Lessor shall repair all leaks in the roof which result from ordinary wear
and tear. However, if Lessor makes major repairs to the roof, such that in the
opinion of a licensed roofer, that both Lessor and Lessee approve, the roof
should not leak for a period of at least two years after such repairs are made,
then Lessee shall at his sole cost keep and maintain the roof and exterior
walls subsequent to the major repair, including any option periods. Lessor
shall not undertake any repairs that, in the opinion of the mutually agreed
upon roofer, would significantly increase the likelihood of a roof collapse.

41.  Lessor shall maintain throughout the term of this lease and any extension
thereof fire insurance and extended coverage insuring the building and contents
in a minimum amount of $750,000. Lessor is to present to Lessee proof of said
insurance within five (5) days of execution of this lease.
   19
                                                Exhibit B



                               GUARANTEE OF LEASE
                               ------------------


        Reference is made to that certain lease dated September 29, 1981, by and
between Hy-Tech Sciences, Inc., a California corporation, as Lessee, and
Charles A. Grant and Mark L. Greenberg as Lessor, covering the premises at 1440
- 4th Street, Berkeley, California, for a period of five (5) years commencing
December 1, 1981.

         In order to induce the Lessor to enter into the above-referenced lease
with Lessee, Pharmatopes, Inc., an Ohio corporation, hereby guarantees to the
Lessor and to the successor and assigns of Lessor, payment by Lessee of the rent
provided for in said lease and performance by Lessee of all provisions of said
lease.



                                        Pharmatopes, Inc.
                                        An Ohio Corporation



                                        By: /s/
                                            -------------------------------
                                            Treasurer
   20


                               SUBLEASE AGREEMENT

        THIS SUBLEASE AGREEMENT ("Sublease") is entered into as of May 15,
1987, between CALIFORNIA INTEGRATED DIAGNOSTICS, INC., a Delaware corporation
("Sublessor") and SYNCOR INTERNATIONAL CORPORATION, a Delaware corporation
("Sublessee") with reference to the following facts:

                                    RECITALS

        A.      A lease dated September 25, 1981, has been made and entered
into between Charles A. Grant and Mark L. Greenberg (collectively, "Master
Lessor") and Hytech Sciences Incorporated, a California corporation ("Hytech"),
a copy of which is attached hereto as Exhibit A (the "Master Lease"). The
Master Lease was extended pursuant to that certain lease renewal dated August
5, 1986, between Master Lessor and Sublessor under its former name, Integrated
Diagnostics, Inc., a copy of which is attached hereto as Exhibit B (the "Lease
Renewal"). Sublessor is the assignee of Hytech's right, title and interest
under the Master Lease.

        B.      Pursuant to the Master Lease, Master Lessor leased to Sublessor
the premises commonly known as 1440 Fourth Street, Berkeley, California and
more particularly described as Alameda County Assessor's Parcel Nos.
59-2324-1-1 and 59-2324-11-1. The Lease Renewal extended the term of the Master
Lease with respect to that portion of the original premises described as
Alameda County Assessor's Parcel No. 59-2324-1-1 (the "Master Premises").

        C.      Sublessor wishes to sublease a portion of the Master Premises
to Sublessee and Sublessee wishes to lease such portion of the Master Premises
from Sublessor.

        NOW, THEREFORE, in consideration of the foregoing, the parties hereto
mutually covenant and agree as follows:

        1.      Subleased Premises. Subject to each of the following terms and
conditions, Sublessor leases to Sublessee and Sublessee leases from Sublessor
the following described premises (the "Premises"):

        that portion of the Master Premises, as more
        particularly described in Exhibit C attached
        hereto, which at May 15, 1987 is occupied by
        Radiopharmacy of Sublessee.

        2.      Term.  The term of this Sublease shall be for one year
commencing on the date hereof and ending on May 15, 1988, unless sooner
terminated pursuant to the terms hereof provided,

        
   21


however, that Sublessee may terminate at any time after November 15, 1987 upon
60 days written notice.

        3.      Rent.

                (a)  Sublessee shall pay to Sublessor as basic rental for the
use and occupancy of the Premises $1,700 per month, payable in advance, upon
the 15th day of each and every calendar month during the term hereof; provided,
however, that the first monthly payment shall be due on May 18, 1987.

                (b)  As additional rent, Sublessee agrees to pay a
proportionate share of the real property taxes and assessments which Sublessor
is required to pay under the Master Lease. Sublessee's proportionate share of
such real property taxes and assessments shall be based upon the proportion of
the square footage of the Premises to that of the square footage of the Master
Premises. 

                (c)  Sublessee acknowledges that the late payment by Sublessee
to Sublessor of rent or other sums due hereunder will cause Sublessor to incur
costs not contemplated by this Sublease, the exact amount of which will be
extremely difficult to determine. Accordingly, if any installment of rent or
other sum due from Sublessee shall not be received by Sublessor within eleven
days of the date such payment is due, then Sublessee shall pay to Sublessor a
late charge equal to ten percent of such overdue amount. The parties agree that
such late charge represents a fair and reasonable estimate of the costs that
Sublessor will incur by reason of the late payment by Sublessee. Acceptance of
such late charges by Sublessor shall in no event constitute a waiver of
Sublessee's default with respect to such overdue amount, nor prevent Sublessor
from exercising any of the other rights and remedies granted hereunder.

                (d)  All rent shall be paid to Sublessor at 433 Industrial Way,
Benecia, California 94510, Attention: Accounts Receivable, or at such other
place as Sublessor may from time to time designate in writing.

        4.      [This section intentionally left blank.]

        5.      Utilities.  The utilities, including without limitation, water,
gas, heat, electricity, sewer and refuse, supplied to the Premises are to be
paid by Sublessor.

        6.      Lavoratory; Lunchroom.  Sublessee shall have the right, which
right shall be appurtenant to the leasehold interest in the Premises granted to
Sublessee hereunder, to use in common with Sublessor the lavoratories, the
lunchroom, hallways and reception area located in the Master Premises.


                                       2


   22
        7.      Parking.  Sublessee shall have the right, which right shall be
appurtenant to the leasehold interest in the Premises granted to Sublessee
hereunder, to use parking spaces consistent with prior usage.

        8.      Use of Premises.  Sublessee shall use the Premises for general
office purposes and for the operation of a Radiopharmacy. Sublessee shall not
use or permit the Premises to be used for any other purposes.

        9.      Assignment; Sublease.  Sublessee shall not assign this Sublease
or sublet any portion of the Premises without the prior written consent of
Sublessor.

        10.     Master Lease.  The parties intend that, except as otherwise set
forth below, Sublessee shall have the same rights and obligations hereunder
with respect to the Premises as Sublessor has under the Master Lease.
Accordingly: 

                (a)  Sublessee hereby acknowledges that it has read and
understands the provisions of the Master Lease.

                (b)  Sublessee hereby expressly assumes and agrees during the
term of this Sublease to perform all of Sublessor's obligations as lessee under
the Master Lease, insofar as such obligations relate to the Premises,
provided that:

                     (i)  Sublessee shall not be responsible for the provisions
of Section 1 (security deposit), 11 (utilities) and 31 (increases in rent) of
the Master Lease; and

                     (ii)  Sections 4 (right to make alterations), 32 (right to
extend term), 33 (right of first refusal), 36 (right to make alterations) and
37 (right of cancellation) of the Master Lease and Section 2 of the Lease
Renewal (right to terminate Master Lease) shall not be applicable to Sublessee.

                (c)  To the extent the provisions of the Master Lease and this
Sublease are contradictory, the provisions of this Sublease shall control.

                (d)  Sublessee shall indemnify, release and hold Sublessor, its
agents, officers and employees, harmless from all suits, actions, damages,
liability, loss and expense including, without limitation, attorneys' fees,
arising from Sublessee's failure to comply with or perform the obligations it
has herein agreed to comply with and perform under the Master Lease.

                                       3

   23
        (e)     During the term of this Sublease, as long as Sublessee is not
in default under this Sublease, Sublessor agrees that it shall perform all of
its obligations under the Master Lease to the end that the Sublessee's quiet
enjoyment of the Premises not be disturbed by any default on the part of the
Sublessor under the Master Lease.

        11.     Entry and Inspection. Sublessor or its agents shall have the
right, upon 24 hours notice to Sublessee, to enter upon the Premises for any
purpose reasonably related to this Sublease and/or the Master Lease. If
Sublessor so enters upon the Premises it shall conduct its activities in a
manner that does not unreasonably interferes with Sublessee's business.

        12.     Condition of Premises. The parties agree that the Premises are
subleased by Sublessor on an "as is" basis without preparation, cleaning or
leasehold improvements of any kind. By taking possession of the Premises,
Sublessee accepts the Premises as suitable for the purpose for which the
Premises were leased. Sublessee acknowledges that neither Sublessor nor
Sublessor's agents have made any representation or warranty as to the
suitability or condition of the Premises.

        13.     Alterations; Additions; Improvements. Sublessee will not make
or allow to be made any alteration, addition or improvement in or to the
Premises except upon the prior written consent of Sublessor. Sublessor agrees
not to unreasonably withhold consent to alterations which are necessary to
Sublessee's performance of its repair and maintenance obligations hereunder and
under the Master Lease.

        14.     Brokerage. Each party represents and warrants that neither it
nor its officers or agents or any one acting on its behalf has employed any
broker or finder in connection with the transaction contemplated hereby and no
liability has been incurred or will be incurred by or on its behalf, directly
or indirectly, for any agent's, broker's or finder's fees or commissions in
connection with the transaction contemplated hereby. Each party hereby
indemnifies and agrees to defend, save and hold the other party harmless from
any such liability or claims.

        15.     Indemnification. Sublessor shall not be liable to Sublessee or
to Sublessee's agents, employees, guests, invitees or to any person claiming
by, through or under Sublessee for any injury to person, loss or damage to
property, or for loss or damage to Sublessee's business, occasioned by or
through the acts of omissions of Sublessor or any other person, or by any other
cause whatsoever, except Sublessor's gross negligence or intentional tortious
acts, and Sublessee expressly waives any such liability. In addition, Sublessee

                                       4
   24
hereby indemnifies Sublessor, its agents, officers and employees against and
agrees to defend and save Sublessor, its agents, officers and employees
harmless from all suits, actions, damages, liability, loss and expense,
including without limitation, attorneys' fees, in connection with any loss of
life, bodily or personal injury or property damage sustained by any person or
property and arising from or out of any occurrence in or about the Premises or
arising from or out of the occupancy or use by Sublessee of the Premises or any
part thereof caused directly or indirectly by Sublessee or its agents,
employees, guests or invitees.

        16. Insurance

        (a) At all times during the term of this Sublease, Sublessee shall, at
Sublessee's sole cost, obtain and maintain comprehensive general public
liability insurance, naming Lessor, Sublessor and Sublessee as insureds and
insuring Sublessee and Sublessor against any liability to the public or to
their guests, invitees or licensees, incident to the ownership, maintenance,
management, and/or use of the Premises arising from claims for personal injury,
death or property damage occurring upon, in or about the Premises. Limits of
liability under such insurance shall be not less than amounts currently carried
by Sublessee.

        (b) At all times during the term of this Sublease, Sublessee shall, at
Sublessee's sole cost, obtain and maintain products liability insurance, naming
both Sublessor and Sublessee as insureds. Limits of liability under such
insurance shall be subject to Sublessee's reasonable approval, but shall not be
less than the amounts typically carried by entities which operate and conduct
the type of business operated and conducted by Sublessee.

        (c) Within three (3) days of the execution of this Sublease, Sublessee
shall deliver to Sublessor a true and correct copy of each policy of insurance
required to be obtained and maintained hereunder or a certificate evidencing
such policy executed by the insurer.

        17. Surrender of Premises. Sublessee agrees to surrender the Premises
immediately upon the termination of this Sublease in the same condition as when
received by Sublessee, reasonable use and wear thereof accepted.

        18. Notice. Any notice required or permitted to be given hereunder by 
one party to the other shall be in writing and shall be deemed to have been 
given when personally delivered, or, if mailed, when deposited in the United 
States Mail for mailing by certified or registered mail, with

                                       5
   25
sufficient postage prepaid, addressed to the respective party to whom notice is
intended to be given at the following address of such party:

        If to Sublessor:        The InFerGene Company   
                                433 Industrial Way
                                Benicia, CA 94510

        If to Sublessee:        Syncor International Corporation
                                20001 Prairie Street
                                Chatsworth, CA 91311

Any party may change the address of such party set forth above by giving notice
of such change to the other party in conformance with the provisions of this
Section 18.

        19. Successors and Assigns. Subject to the provisions of Section 9, the
provisions of this Sublease shall be binding upon and inure to the benefit of
the parties hereto and their respective successors and assigns.

        20. Time of Essence. It is expressly understood and agreed that time is
of the essence of each and every provision of this Sublease.

        21. Attorneys' Fees. In any legal action brought by either party to
enforce enforce the terms hereof or relating to the Premises, the prevailing
party shall be entitled to all costs incurred in connection with such action,
including reasonable attorneys' fees.

        IN WITNESS WHEREOF, the parties hereto have executed this Sublease as
of the date first above written.

                                SUBLESSOR:

                                CALIFORNIA INTEGRATED DIAGNOSTICS, INC.


                                By: /s/
                                    __________________________________

                                Its: Chairman and CEO
                                    ----------------------------------


                                SUBLESSEE:

                                SYNCOR INTERNATIONAL CORPORATION


                                By: /s/
                                    __________________________________

                                Its: President and C.O.O.
                                    ----------------------------------
                                



                                       6
   26
                                   Exhibit B
                                   ---------

                                                                August 5, 1986

                                 LEASE RENEWAL

The undersigned hereby agree to the renewal of the lease dated September 25,
1981 of the property at 1440 4th Street for a second five year period as
specified in paragraph 32 of the lease. All terms of the lease will remain
exactly as specified in the lease except as follows:

1.   The leased premises is reduced to include only Parcel number 59-2324-1-1.
     Parcel 59-2324-11 is excluded from the lease for this five year renewal
     period and any subsequent renewal periods.

2.   The lease may be terminated by the Lessee on any anniversary date of the
     lease* during the five year renewal period provided a written notice of
     intention to terminate is given to Lessor at least 120 days prior to the
     anniversary date.

                    *said anniversary date being December 1

                Lessors                                 Lessee

                                              Integrated Diagnostics, Inc.

         /s/ Mark Greenberg                        /s/ Mark S. F?????
     -------------------------                 ---------------------------
          Mark Greenberg                                 Name

       /s/ Charles A. Grant                        Chairman & CEO
     -------------------------                 ---------------------------
          Charles A. Grant                               Title

     DATE:    8/14/86                          DATE:   August 8, 1986
           -------------------                       ---------------------


   27




                             [DIAGRAM OF PROPERTY]


   28
              CONSENT TO SUBLEASE AND LEASE MODIFICATION AGREEMENT

THIS CONSENT TO SUBLEASE AND LEASE MODIFICATION AGREEMENT (this "Agreement") is
entered into as of May 15, 1987, between CHARLES A. GRANT and MARK L. GREENBERG
(collectively "Landlord") and CALIFORNIA INTEGRATED DIAGNOSTICS, INC., a
Delaware corporation ("Tenant"), with reference to the following facts:

                                    RECITALS

        A. Landlord and Tenant's predecessor in interest, Hytech Sciences
Incorporated, a California corporation, entered into that certain lease dated
September 25, 1981 (the "Master Lease") whereby Landlord leased to Tenant the
premises described in the Master Lease (the "Master Premises"). The term of the
Master Lease was extended pursuant to that certain lease renewal dated August
5, 1986, between Landlord and Tenant (the "Lease Renewal").

        B. The performance of Tenant's rental obligations under the Master
Lease are guaranteed (the "Guaranty") by Syncor Corp., an Ohio corporation,
formerly named Pharmatopas, Inc., an Ohio corporation ("Syncor").

        C. Tenant wishes to sublease a portion of the Master Premises (the
"Subleased Premises") to Syncor International Corp., a Delaware corporation
("Sublessee), in accordance with the terms of that certain sublease dated as of
the date hereof, a copy of which is attached hereto as Exhibit A (the
"Sublease").

        D. In addition, Landlord and Tenant wish to modify certain provisions
of the Lease Renewal.

        NOW, THEREFORE, in consideration of the foregoing, the parties hereto
mutually covenant and agree as follows:

        1.      Consent to Sublease.

                (a) Landlord hereby consents to and agrees to the terms of the
Sublease attached hereto.

                (b) Landlord represents and warrants that (i) the Master Lease
is in full force and effect and (ii) there exists no event of which Landlord is
aware of default under the Master Lease or any event which but for the passage
of time or the giving of notice would constitute a default.

   29
                (c) Landlord covenants and agrees that during such time as
Sublessee is not in default under the Sublease, Sublessee's interest in and
occupancy and possession of the Subleased Premises shall not be extinguished
or terminated.

                (d) Tenant warrants that the Sublease does not impair the
rights of the Landlord or limit the obligations of Tenant to Landlord under the
Master Lease.

        2.      Termination of Guaranty.  Landlord hereby releases Syncor from
any and all of its obligations under the Guaranty and agrees that the Guaranty
is of no further force or effect.

        3.      Guarantee. The InferGene Company hereby guarantees the payment
by Tenant of the rent provided for in said Master Lease and performance by
Tenant of all provisions of said Master Lease.

        4.      Modification of Lease Renewal. Section 2 of the Lease Renewal
is amended in its entirety as follows:

                "2. Commencing after December 1, 1987, and during the five year
        renewal period, the Lease may be terminated by Lessee, effective on any
        anniversary date of the Lease arising after December 1, 1987, provided
        Lessee delivers to Lessor written notice of its intention to terminate
        the Lease at least 180 days prior to the next anniversary date upon
        which Lessee desires the Lease to terminate. The parties agree that the
        anniversary date for the Lease is December 1.

        IN WITNESS WHEREOF, the parties hereto have duly executed this
Agreement as of the date first above written.

                                LANDLORD

                                       /s/   Charles A. Grant
                                ------------------------------------------
                                             Charles A. Grant


                                       /s/    Mark Greenberg
                                ------------------------------------------
                                             Mark L. Greenberg
  
                                       2
   30
                                      TENANT:

                                      CALIFORNIA INTEGRATED DIAGNOSTICS, INC.


                                      By   /s/ Mark S. F???????
                                           ------------------------------------
                                      Its  Chairman & CEO
                                           ------------------------------------

                                      GUARANTOR:

                                      THE INFERGENE COMPANY


                                      By   Bernard DiDanio
                                           ------------------------------------





                                       3

   31
                                   Exhibit A
                                   ---------

                               SUBLEASE AGREEMENT

        THIS SUBLEASE AGREEMENT ("Sublease") is entered into as of May 15,
1987, between CALIFORNIA INTEGRATED DIAGNOSTICS, INC., a Delaware corporation
("Sublessor") and SYNCOR INTERNATIONAL CORPORATION, a Delaware corporation
("Sublessee") with reference to the following facts:

                                    RECITALS

        A.  A lease dated September 25, 1981, has been made and entered into
between Charles A. Grant and Mark L. Greenberg (collectively, "Master Lessor")
and Hytech Sciences Incorporated, a California corporation ("Hytech"), a copy
of which is attached hereto as Exhibit A (the "Master Lease"). The Master Lease
was extended pursuant to that certain lease renewal dated August 5, 1986,
between Master Lessor and Sublessor under its former name, Integrated
Diagnostics, Inc., a copy of which is attached hereto as Exhibit B (the "Lease
Renewal"). Sublessor is the assignee of Hytech's right, title and interest
under the Master Lease.

        B.  Pursuant to the Master Lease, Master Lessor leased to Sublessor the
premises commonly known as 1440 Fourth Street, Berkeley, California and more
particularly described as Alameda County Assessor's Parcel Nos. 59-2324-1-1 and
59-2324-11-1. The Lease Renewal extended the term of the Master Lease with
respect to that portion of the original premises described as Alameda County
Assessor's Parcel No. 59-2324-1-1 (the "Master Premises").

        C.  Sublessor wishes to sublease a portion of the Master Premises to
Sublessee and Sublessee wishes to lease such portion of the Master Premises
from Sublessor.

        NOW, THEREFORE, in consideration of the foregoing, the parties hereto
mutually covenant and agree as follows:

        1.  Subleased Premises. Subject to each of the following terms and
conditions, Sublessor leases to Sublessee and Sublessee leases from Sublessor
the following described premises (the "Premises"):

        that portion of the Master Premises, as more particularly described in
        Exhibit C attached hereto, which at May 15, 1987 is occupied by
        Radiopharmacy of Sublessee.

        2.  Term. The term of this Sublease shall be for one year commencing on
the date hereof and ending on May 15, 1988, unless sooner terminated pursuant
to the terms hereof provided,

   32
however, that Sublessee may terminate at any time after November 15, 1987 upon
60 days written notice.

        3.      Rent.

                (a)  Sublessee shall pay to Sublessor as basic rental for the
use and occupancy of the Premises $1,700 per month, payable in advance, upon
the 15th day of each and every calendar month during the term hereof; provided,
however, that the first monthly payment shall be due on May 18, 1987.

                (b)  As additional rent, Sublessee agrees to pay a
proportionate share of the real property taxes and assessments which Sublessor
is required to pay under the Master Lease. Sublessee's proportionate share of
such real property taxes and assessments shall be based upon the proportion of
the square footage of the Premises to that of the square footage of the Master
Premises. 

                (c)  Sublessee acknowledges that the late payment by Sublessee
to Sublessor of rent or other sums due hereunder will cause Sublessor to incur
costs not contemplated by this Sublease, the exact amount of which will be
extremely difficult to determine. Accordingly, if any installment of rent or
other sum due from Sublessee shall not be received by Sublessor within eleven
days of the date such payment is due, then Sublessee shall pay to Sublessor a
late charge equal to ten percent of such overdue amount. The parties agree that
such late charge represents a fair and reasonable estimate of the costs that
Sublessor will incur by reason of the late payment by Sublessee. Acceptance of
such late charges by Sublessor shall in no event constitute a waiver of
Sublessee's default with respect to such overdue amount, nor prevent Sublessor
from exercising any of the other rights and remedies granted hereunder.

                (d)  All rent shall be paid to Sublessor at 433 Industrial Way,
Benecia, California 94510, Attention: Accounts Receivable, or at such other
place as Sublessor may from time to time designate in writing.

        4.      [This section intentionally left blank.]

        5.      Utilities.  The utilities, including without limitation, water,
gas, heat, electricity, sewer and refuse, supplied to the Premises are to be
paid by Sublessor.

        6.      Lavoratory; Lunchroom.  Sublessee shall have the right, which
right shall be appurtenant to the leasehold interest in the Premises granted to
Sublessee hereunder, to use in common with Sublessor the lavoratories, the
lunchroom, hallways and reception area located in the Master Premises.


                                       2
   33
        7.  Parking.  Sublessee shall have the right, which right shall be
appurtenant to the leasehold interest in the Premises granted to Sublessee
hereunder, to use parking spaces consistent with prior usage.

        8.  Use of Premises.  Sublessee shall use the Premises for general
office purposes and for the operation of a Radiopharmacy. Sublessee shall not
use or permit the Premises to be used for any other purposes.

        9.  Assignment; Sublease.  Sublessee shall not assign this Sublease or
sublet an portion of the Premises without the prior written consent of
Sublessor. 

        10.  Master Lease.  The parties intend that, except as otherwise set
forth below, Sublessee shall have the same rights and obligations hereunder
with respect to the Premises as Sublessor has under the Master Lease.
Accordingly: 

                (a)  Sublessee hereby acknowledges that it has read and
understands the provisions of the Master Lease.

                (b)  Sublessee hereby expressly assumes and agrees during the
term of this Sublease to perform all of Sublessor's obligations as lessee under
the Master Lease, insofar as such obligations relate to the Premises, provided
that: 

                        (i)  Sublessee shall not be responsible for the
provisions of Sections 1 (security deposit), 11 (utilities) and 31 (increases
in rent) of the Master Lease; and

                        (ii)  Sections 4 (right to make alterations), 32 (right
to extend term), 33 (right of first refusal), 36 (right to make alterations)
and 37 (right of cancellation) of the Master Lease and Section 2 of the Lease
Renewal (right to terminate the Master Lease) shall not be applicable to
Sublessee. 

                (c)  To the extent the provisions of the Master Lease and this
Sublease are contradictory, the provisions of this Sublease shall control.

                (d)  Sublessee shall indemnify, release and hold Sublessor, its
agents, officers and employees, harmless from all suits, actions, damages,
liability, loss and expense including, without limitation, attorneys' fees,
arising from Sublessee's failure to comply with or perform the obligations it
has herein agreed to comply with and perform under the Master Lease.


                                       3

   34
                (e) During the term of this Sublease, as long as Sublessee is
not in default under this Sublease, Sublessor agrees that it shall perform all
of its obligations under the Master Lease to the end that Sublessee's quiet
enjoyment of the Premises not be disturbed by any default on the part of
Sublessor under the Master Lease.

        11.     Entry and Inspection.  Sublessor or its agents shall have the
right, upon 24 hours notice to Sublessee, to enter upon the Premises for any
purpose reasonably related to this Sublease and/or the Master Lease. If
Sublessor so enters upon the Premises it shall conduct its activities in a
manner that does not unreasonably interferes with Sublessee's business.

        12.     Condition of Premises. The parties agree that the Premises are
subleased by Sublessor on an "as is" basis without preparation, cleaning or
leasehold improvements of any kind. By taking possession of the Premises,
Sublessee accepts the Premises as suitable for the purpose for which the
Premises were leased. Sublessee acknowledges that neither Sublessor nor
Sublessor's agents have made any representation or warranty as to the
suitability or condition of the Premises.

        13.     Alterations; Additions; Improvements. Sublessee will not make
or allow to be made any alteration, addition or improvement in or to the
Premises except upon the prior written consent of Sublessor. Sublessor agrees
not to unreasonably withhold consent to alterations which are necessary to
Sublessee's performance of its repair and maintenance obligations hereunder and
under the Master Lease.

        14.     Brokerage. Each party represents and warrants that neither it
nor its officers or agents or any one acting on its behalf has employed any
broker or finder in connection with the transaction contemplated hereby and no
liability has been incurred or will be incurred by or on its behalf, directly
or indirectly, for any agent's, broker's or finder's fees or commissions in
connection with the transaction contemplated hereby. Each party hereby
indemnifies and agrees to defend, save and hold the other party harmless from
any such liability or claims.

        15.     Indemnification. Sublessor shall not be liable to Sublessee or
to Sublessee's agents, employees, guests, invitees or to any person claiming
by, through or under Sublessee for any injury to person, loss or damage to
property, or for loss or damage to Sublessee's business, occasioned by or
through the acts of omissions of Sublessor or any other person, or by any other
cause whatsoever, except Sublessor's gross negligence or intentional tortious
acts, and Sublessee expressly waives any such liability. In addition, Sublessee

                                       4
   35
hereby indemnifies Sublessor, its agents, officers and employees against and
agrees to defend and save Sublessor, its agents, officers and employees
harmless from all suits, actions, damages, liability, loss and expense,
including without limitation, attorneys' fees, in connection with any loss of
life, bodily or personal injury or property damage sustained by any person or
property and arising from or out of any occurrence in or about the Premises or
arising from or out of the occupancy or use by Sublessee of the Premises or any
part thereof caused directly or indirectly by Sublessee or its agents,
employees, guests or invitees. 

        16.  Insurance.

                (a)  At all times during the term of this Sublease, Sublessee
shall, at Sublessee's sole cost, obtain and maintain comprehensive general
public liability insurance, naming both Sublessor and Sublessee as insureds and
insuring Sublessee and Sublessor against any liability to the public or to
their guests, invitees or licensees, incident to the ownership, maintenance,
management and/or use of the Premises arising from claims for personal injury,
death or property damage occurring upon, in or about the Premises. Limits of
liability under such insurance shall be not less than amounts currently carried
by Sublessee. 

                (b)  At all times during the term of this Sublease, Sublessee
shall, at Sublessee's sole cost, obtain and maintain products liability
insurance, naming both Sublessor and Sublessee as insureds. Limits of liability
under such insurance shall be subject to Sublessee's reasonable approval, but
shall not be less than the amounts typically carried by entities which operate
and conduct the type of business operated and conducted by Sublessee. 

                (c)  Within three (3) days of the execution of this Sublease,
Sublessee shall deliver to Sublessor a true and correct copy of each policy of
insurance required to be obtained and maintained hereunder or a certificate
evidencing such policy executed by the insurer. 

        17.  Surrender of Premises.  Sublessee agrees to surrender the Premises
immediately upon the termination of this Sublease in the same condition as when
received by Sublessee, reasonable use and wear thereof accepted.

        18.  Notice.  Any notice required or permitted to be given hereunder
by one party to the other shall be in writing and shall be deemed to have been
given when personally delivered, or, if mailed, when deposited in the United
States Mail for mailing by certified or registered mail, with 


                                       5


   36
sufficient postage prepaid, addressed to the respective party to whom notice is
intended to be given at the following address of such party:

        If to Sublessor:  The InFerGene Company
                          433 Industrial Way
                          Benicia, CA 94510

        If to Sublessee:  Syncor International Corporation
                          20001 Prairie Street
                          Chatsworth, CA 91311

Any party may change the address of such party set forth above by giving notice
of such change to the other party in conformance with the provisions of this
Section 18.

        19.  Successors and Assigns.  Subject to the provisions of Section 9,
the provisions of this Sublease shall be binding upon and inure to the benefit
of the parties hereto and their respective successors and assigns.

        20.  Time of Essence.  It is expressly understood and agreed that time
is of the essence of each and every provision of this Sublease.

        21.  Attorneys' Fees.  In any legal action brought by either party to
enforce the terms hereof or relating to the Premises, the prevailing party
shall be entitled to all costs incurred in connection with such action,
including reasonable attorneys' fees.

        IN WITNESS WHEREOF, the parties hereto have executed this Sublease as
of the date first above written.

                                        SUBLESSOR:

                                        CALIFORNIA INTEGRATED DIAGNOSTICS, INC.


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

                                        Its: 
                                             ----------------------------------


                                        SUBLESSEE:

                                        SYNCOR INTERNATIONAL CORPORATION


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

                                        Its: 
                                             ----------------------------------


                                       6

   37
34.  Lessor will, at Lessor's sole cost and expense, make all the repairs
listed below. These repairs will be made promptly upon execution of this lease
and continue expeditiously until it is completed. Said completion shall be no
later than two (2) months from the date of execution hereon; however, Lessee to
hold Lessor harmless for any delays which are beyond the control of Lessor and
it is further understood that the date these repairs are completed shall not
affect the commencement date of this lease.

        1.      Clean entryway carpet

        2.      Vacuum all rugs and carpets

        3.      Trim trees and bushes on exterior of building and remove weeds
                in paved parking lot

        4.      Fix or replace all broken or missing ceiling tiles

        5.      Repair all broken windows

        6.      Fill or fix potholes in parking lot

        7.      Clean up debris and garbage on exterior of property

        8.      Remove all realtor signs

        9.      Clean up kitchen areas and bathroom

       10.      Supply Lessee with keys to all doors and thermostat

       11.      Clear drain in parking lot if first rain shows that it is
                clogged. 

       12.      Repair broken tiles in bathroom

       13.      Install a door to phone access and bathroom