
<PAGE>   1
                                                                   EXHIBIT 10.36



                 GREATER DALLAS ASSOCIATION OF REALTORS, INC.



[REALTOR (R) LOGO]                              [EQUAL HOUSING OPPORTUNITY LOGO]


                        NET COMMERCIAL LEASE AGREEMENT

                                                              STATE OF TEXAS
                                                              COUNTY OF DALLAS
                                                                        ------

           THIS LEASE AGREEMENT made and entered into by and between


                                       
                           DALLAS PATHOLOGY LEASING

hereinafter referred to as "Landlord," and


                                       
                                 UNIPATH, LTD.



hereinafter referred to as "Tenant."                                    



                                  WITNESSETH:

   Landlord hereby leases to Tenant, and Tenant hereby takes from Landlord the
following described premises (hereinafter referred to as the "desired premises"
or "premises") situated within the County of Dallas State of Texas


        4350 Alpha Road, Dallas, Texas


















together with all rights, privileges, easements and appurtenances belonging to
or in any way pertaining to the desired premises and together with the building
and other improvements now situated or to be erected upon the demised premises.


    TO HAVE AND TO HOLD the same for a term of    sixty (60) months


beginning on    June 1, 1995                               , upon the following
terms, conditions and covenants:


I.  RENT: Tenant agrees to pay the Principal Broker named herein, without offset
or deduction, for the account of Landlord rent for the demised premises at the
rate of Eight Thousand Six Hundred Fifty-Five Dollars and 84/100 _________
Dollars $ 8,655.84                  ) per month in advance.  One such monthly
installment shall be due and payable on or before 
the beginning date of this lease, and a like monthly installment shall be due
and payable on or before the first day of each succeeding calendar month during
the term hereof; provided that in the event the lease hereof shall commence or
end during a calendar month, the rent for any financial calendar month
following the commencement or preceding the end of the term of this lease shall
be pro rated by days.  (If percentage rent is to be payable to Landlord, refer
to Exhibit A attached to this lease.  In such case Exhibit A shall be
incorporated into and become a part of this lease where physically attached
hereto.)


    Tenant has deposited with Landlord, upon delivery of this lease.


Dollars ($ 8,655.84     ) to be applied as follows:

        (a) $ 8,655.84    for rent for June 1995.
  
<PAGE>   2
   2.  ACCEPTANCE OF PREMISES:

   Tenant acknowledges that it has fully inspected the demised premises and
accepts the demised premises, and any buildings and improvements situated
thereon, as suitable for the purpose for which the same are leased in their
present condition, except


(If this lease provides for a building to be constructed for Tenant, refer to
Exhibit B attached to this lease.  In such case this paragraph shall become
inapplicable, and Exhibit B shall be incorporated into and become a part of
this lease when physically attached herein.)

   3.  USE OF PREMISES:

   The demised premises shall be used and occupied only for the purpose of



and not otherwise.  Tenant shall at its own expense obtain any and all
governmental licenses and permits necessary for such use.

   4.  COMPLIANCE WITH LAW:

       Tenant shall comply with all governmental laws, ordinances and
regulations applicable to the use of demised premises, and shall promptly
comply with all governmental orders and directives for the correction,
prevention and abatement on or upon, or connected with the demised premises,
all at Tenant's sole expense.


   5.  REAL ESTATE TAXES:

   (a) Tenant agrees to pay before they become delinquent all taxes (both
general and special), assessments or governmental of any kind and nature
whatsoever (hereinafter referred to as the "taxes"), levied or assessed against
the appropriate taxing authority or other evidence satisfactory to landlord
evidencing payment thereof.  If Tenant shall fail to pay any taxes,
assessments, or governmental charges required to be paid by Tenant hereunder,
in addition to any other remedies provided herein, Landlord may if it so
elects pay such taxes, assessments, and governmental charges.  Any sums so paid
by Landlord shall be decreed to do so much additional rental owing by Tenant to
Landlord and due and payable on written demand by Landlord together with 
interest thereon at the rate of temper exit (10%) per annum from date paid by
Landlord to date of repayment by Tenant.

   (b) All real estate taxes and assessments on the demised premises owned by
Landlord shall be promised between landlord and Tenant with respect to the tax
years in which this lease commences or terminates.  Tenant shall pay that part
of the real estate taxes attributable to the portion of the tax year covered by
this lease.

   (c) In the event the premises constitute a portion of multiple occupancy
building, in lieu of Tenant paying the "taxes" as above provided. Landlord
agrees to pay before they become all delinquent all "taxes" lawfully levied or
assessed against such building and the grounds, parking areas, driveways and
alleys around the said building, and Tenant agrees to pay to Landlord upon
written demand the amounts of Tenant's "proportional share" of all such "taxes"
paid by Landlord.  Tenant's "proportionate share," as used throughout this
lease, shall mean a fraction, the numerator of which is a space occupied by
Tenant and the denominator of which is the entire gross space contained in the
building.

   (d) Tenant may, alone or along with any other tenants of said building, at
its or their sole cost and expense, in its or their own name(s) and/or in the
name of the Landlord dispute and contest any "taxes" by appropriate proceedings
diligently conducted in good faith, but only after Tenant and all other
tenants, if any, joining with Tenant in such contest have deposited with
landlord the amount of so contested and unpaid, or their proportionate shares
thereof as the case may be, which shall be held by Landlord without obligations
for intent until the termination of the proceedings), and Tenant's share of any
excess shall be returned to Tenant.  Tenant further agrees to pay to Landlord
upon demand Tenant's share (as among all Tenants who participated in the
context) and Tenant's share of any excess shall be returned to Tenant.  Tenant
further agrees to pay to landlord upon demand Tenant's share (as among all
tenants who participated in the contest) of all court costs, interest,
penalties and other liabilities relating to such proceedings.  Tenant hereby
indemnifies and agrees to hold harmless the landlord from and against any cost,
damages or expense, including attorney's fees in connection with any such
proceedings.

   (e) If at any time during the term of this Lease, the present method of
taxation shall be changed so that in lieu of the whole or any part of the
taxes, acceptances, levies or charges levied, assessed or imposed  Landlord a
capital levy or other tax directly on the rents received therefrom and/or a
franchise, assessment, levy or charge measured by or based, in whole or in
part, upon such rests or the present or any future building or buildings on the
premises, then all such taxes, assessments, levies or charges, or the part
thereof so measured or based, shall be deemed to be included within the term
"taxes" for the purpose thereof.

   6.  REPAIRS AND MAINTENANCE

   (a) Tenant shall at its own cost and expense keep, maintain and take good
care of the premises and make all necessary thereto, interior and exterior,
structural and not-structural, ordinary and extraordinary, and shall suffer no
waste or nuisance provided, however, that the cost of maintenance and
repair of any company pantry wall (any wall, divider, partition or any other
structure repairing the premises from any adjacent premises occupied by other
tenants) shall be shared equally by Tenant and the Tenant occupying adjacent
premises.  Tenant shall not damage any party wall or disturb the integrity and
support provided by any part wall and shall, at its costs and expense, promptly
repair any damage or injury to any party wall caused by Tenant or its
employees, agents or invitees.  At the end of the term of other termination of
this lease, Tenant shall deliver the premises with all improvements thereon in
good repair and conditions, reasonable wear and tear only excepted.
   
   (b)  Tenant shall as its own cost and expense care for the grounds around
the buildings on the premises, including the regular mowing of grass, care of
shrubs and general landscaping, and maintenance of the parking areas,
driveways, alleys and shall maintain the whole of the premises in a clean and 
sanitary condition.

   (c)  In the event the premises constitute a portion of multiple occupancy
building. Tenant and its employees, customers, and licenses shall have the
nonexclusive right to use in common with the other parties occupying said
building, the parking areas, driveways and alley in concurrence with the other
parties, the parking areas, driveways and alleys adjacent to said building, 
subject to such reasonable rules and regulations as Landlord may from
time to time prescribe and Tenant shall in lieu of the obligations set forth
under subparagraph (b) above, be liable for its proportional share of the costs
and expense of the care for the grounds around the said building, including but
not limited to the mowing of grass, care of shrubs, general landscaping, and
maintenance of parking ares, driveways and alleys.  Tenant shall as Landlord's
option either (i) pay when dues is proportionate share of such costs and 
expenses along with the other tenants of the building directly to the persons
performing such work, or (ii) reimburse Landlord upon demand for the amount of
its proportionate share of such costs and expenses in the event Landlord elects
to perform or cause to be performed such work.

   (d) In the event the premises constitute a portion of multiple occupancy
building, Landlord shall be responsible for coordinating any repairs and other
maintenance of any rail tracks serving or to serve the building, and Tenant
shall reimburse Landlord for Tenant's proportionate share of the costs of such
repairs and maintenance and any other sums specified in any agreement to
which Landlord is a party respecting such tracks.

   (e)  In the event Tenant shall fail to maintain the demised premises or
any paving, landscaping or railroad siding in accordance with this paragraph 6.
Landlord shall have the right (but not the obligation) to cause all repairs or
other maintenance to be made and the reasonable costs therefor expended by 
Landlord shall be paid by Tenant on written demand.

   7.  ALTERATIONS, ADDITIONS AND IMPROVEMENTS.

   Tenant shall not create any openings in the roof or exterior walls, or may
all alterations, additions or improvements to the demise premises without prior
written         

<PAGE>   3
consent of Landlord. Consent for non-structural alterations, additions or
improvements shall not be unreasonably withheld by Landlord. Tenant shall have
the right to erect or install shelves, bins, machinery, air conditioning or
heating equipment and trade fixtures, provided that Tenant complies with all
applicable governmental laws, endurances and regulations. At the expiration or
termination of this lease, Tenant shall have the right to remove such items as
installed, provided Tenant is not in default at the time of such removal and
provided further that Tenant shall, at time of removal of such items, repair in
a good and workmanlike manner any damages caused by installation or removal
thereof.

         Tenant shall pay for all costs incurred or arising out of alterations,
additions or improvements in or to the demised premises and shall not permit a
mechanic's or materialman's lien to be asserted against the demised premises.
Upon request by Landlord, Tenant shall deliver to Landlord proof of payment
reasonably satisfactory of Landlord of all costs incurred or arising out of any
such alterations, additions or improvements.

         All alterations, additions or improvements in or to the demised
premises shall become the property of Landlord as the expiration or termination
of this lease, however, Landlord may direct the removal of alterations,
additions or improvements by giving written notice to Tenant prior to the
expiration or termination of this lease. At the direction of Landlord, Tenant
shall promptly remove all alterations, additions, and improvements and any other
property placed in the demised premises by Tenant, and Tenant shall repair in a
good and workmanlike manner any damage caused by such removal.

         8.       SIGNS

         Tenants shall not place or affix any signs or other objects upon or to
the roof or exterior walls of the demised premises or paint or otherwise deface
the exterior walls of the demised premises without the prior written consent of
Landlord. Any signs installed by Tenant shall conform with applicable laws and
deed and other restrictions. Tenant shall remove all signs at the termination of
this lease and shall repair any damage and close any holes caused or revealed by
such removal.

         9.       INSURANCE,  FIRE AND CASUALTY DAMAGE:

         (A) Landlord agrees to maintain insurance covering the building of
which the demised premises are a part in an amount not less than 90% (or such
greater percentage as may be necessary to comply with the provisions of any
co-insurance clauses of the policy) of the "replacement cost" thereof as such
terms is defined in the Replacement Cost Endorsement to be attached thereto,
insuring against the perils of Fire, Lightning, Extended Coverage, Vandalism and
Meticulous Mischief, extended by Special Extended Coverage Endorsement to insure
against all other Risks Of Direct Physical Loss, such coverages and endorsements
to be as defined, provided and limited in the standard bureau forms prescribed
by the insurance regulatory authority for the State in which the demised
premises are doomed for use by Insurance companies admitted in such state for
the writing of such insurance on risks located within such state. Subject to the
provisions of subparagraphs 9(b) and 9(e) below, such insurance shall be for
the sole benefit of Landlord and under its sole control. Tenant agrees to pay
Landlord's cost of maintaining such insurance on said building (or, in the event
the premises constitute a portion of a multiple occupancy building. Tenant's
full proportionate share of such costs). Said payments shall be made to landlord
within ten days after presentation to Tenant of Landlord's statement setting
forth the amount due. Any payment to be made permanent to this subparagraph (a)
with respect to the year in which this lease commences or terminates shall bear
the same ratio to the payment which would be required to be made for the full
year, as that part of such year covered by the terms of this lease bears to a
full year.

         (B) If the building situated upon the premises should be damaged or
destroyed by any peril covered by the insurance to be provided by Landlord under
subparagraphs 9(a) above. Tenant shall give immediate notice there to Landlord,
and Landlord shall an its sole costs and expertise thereupon proceed with
reasonable diligence to rebuild and repair such buildings to substantially the
condition in which they existed prior to much damage or direction, except that
Landlord shall not be required to rebuild, repair or replace any part of the
partitions, fixtures, additions or other improvements which may have been placed
in, on or about the premises by Tenant and except that Tenant shall pay to
Landlord upon demand any applicable deductible amounts specified under
Landlord's insurance. The rent payable hereunder shall in no event abate by
reason of any damage or destruction.

         (C) If the buildings situated upon the premises should be damaged or
destroyed by a casualty other than a peril covered by the insurance to be
provided by Landlord under subparagraph 9(a) above, or if any other improvements
situated on the demised premises should be in any manager damaged or destroyed,
Tenant shall at its sole costs and expense thereupon proceed with reasonable
diligence to rebuild and repair such buildings and/or improvements to
substantially the condition in which they existed prior to such damage or
destruction, subject to Landlord's approval of the plans and specifications for
such rebuilding and repairing, which approval shall not be unreasonably
withheld. Tenant's obligation hereunder shall now include destruction of the
premises by war, riot, civil disobedience, or flood.

         (D) Tenant covenants and agrees to maintain insurance on all
alterations, additions, partitions and improvements erected by, or on behalf of,
Tenant in, on or about the demised premises in an amount not less than 90% for
such greater percentage as may be necessary to comply with the provisions of any
co-insurance clause of the policy) of the "replacement cost" thereof as such
term is defined in the Replacement Cost Endorsement to be attached thereto. Such
insurance shall insure against the perils and be in form, including stipulated
endorsements, as provided in subparagraph 9(b) hereof. Such insurance shall be
for the sole benefit of Tenant and under its sole control. All such policies
shall be prepared by Tenant from responsible insurance companies satisfactory to
Landlord. Certified copies of policies of such insurance, together with receipt
evidencing payment of premiums therefore shall be delivered to Landlord prior
the commencement date of this lease. Not less than fifteen (15) days prior to
the expiration date of any such policies, certified copies of renewals thereof
(bearing, nutations evidencing the payment of renewal premiums) shall be
delivered to Landlord. Such polices shall further provide that not less than
thirty (30) days written notice shall be given to Landlord before such policy
may be canceled or changed to reduce insurance provided thereby.

         (E) Notwithstanding anything herein to the contrary, in the event the
holder of any indebtedness secured by a mortgage or deed of trust covering the
premises required that the insurance proceeds be applied to such indebtedness
then the Landlord shall have the right to terminate this lease by delivering
written notice of termination to Tenant within fifteen (15) days after such
requirement is made by any such holder, whereupon all rights and obligations
hereunder shall cease and terminate.

         10.      WAIVER OF SUBROGATION:

         Each party hereto waives any and every claim which arises or may arise
in its favor against the other party hereto during the term of this lease or any
renewal or extension thereof for any and all hereof, or damage, to any of its
property located within or upon, or consulting a part, the demised premises,
which loss or damage is covered by valid and collectible fine and extended
coverage insurance policies, to the extent that such loss or damage is
recoverable under such insurance policies. Such mutual waivers shall be in
addition to, and not in limitations or derogation of, any other waiver or
release contained in this lease with respect to any loss of, or damage, to
property of the parties hereto. Inasmuch as such mutual waivers will preclude
the assignment of any aforesaid claim by way of subrogation or otherwise to an
insurance company (or any other person), each party hereby agrees immediately to
give to each insurance, company which has issued to is polices of fire and
extended coverage insurance written notice of the terms of such mutual waivers,
and to cause such insurance policies to be properly endorsed, if necessary, to
prevent the invalidation of such insurance coverages by reason of such waivers.

         Landlord and its authorized agents shall have the right, during normal
business hours to enter the demised premises (i) to inspect or the general
condition and state of repair thereof, (ii) to make repairs required or
permitted under this lease, (iii) to show the premises to any prospective tenant
or purchaser or (iv) for any other reasonable purpose.

         During the final 150 days of the lease term, Landlord and its
authorized agents shall have the rights to erect and maintain on or about the
demised premises customary signs advertising the property for lease or for sale.

         11.      UTILITY SERVICES.

         Tenant shall pay the (?) of all utility services, including but not
limited to initial connection charges, all charges for gas, water and
electricity used on the demised premises, and for all electric lights, lamps and
(?)

         12.      ASSIGNMENT AND SUBLEASING:

         Tenant shall not, without the prior written consent of Landlord, assign
this lease or sublet premises or any portion thereof. Any assignment or
subletting shall be expressly subject to all terms and provisions of this lease,
including the provisions of paragraphs pertaining to the use of the demised
premises. In the event of any assignment or subletting. Tenant shall remain
fully liable for the full performance of all Tenant's obligations under this
lease. Tenant shall not assign his rights hereunder or sublet the premises
without first obtaining a written agreement from assignee or subleases whereby
assignee or sublessee agrees to be bound by the terms of this lease. No such
assignment or subletting shall constitute a novation. In the event of the
occurrence of an event of default while the demised premises are assigned or
sublet, Landlord, in addition to any other remedies provided herein or by law,
may at landlord's opinion, collect directly form such assignee or subtenant all
rents becoming due under such assignment of subletting and supply such rent
against any sums due to Landlord hereunder. No direct collection by Landlord
from any such assignee or subtenant shall release Tenant from the performance of
its obligations hereunder.


<PAGE>   4
    13.  INDEMNITY AND PUBLIC LIABILITY INSURANCE:

    (a)  Landlord shall not be liable to Tenant or Tenant's employees, agents,
patrons or visitors, or to any other person whatsoever, for any injury to
person or damage to property on or about the premises, caused by negligence or
misconduct of Tenant, its agents, servants or employees, or any other person
entering upon the premises under express or implied invitation of Tenant, or
caused by the buildings and improvements located on the premises becoming out
of repair, or caused by leakage of gas, oil, water or steam or by electricity
emanating from the premises, or due to any cause whatsoever, and Tenant agrees
to indemnify Landlord and hold it harmless from any loss, expenses or losses
including attorneys' fees, arising out of any such damage or injury; except
injury to persons or damage to property the sole cause of which is the
negligence of the Landlord.

     (b)  Tenant shall procure and maintain throughout the term of this lease a
policy or policies of insurance, at its sole cost and expense, insuring both
Landlord and Tenant against all claims, demands, or actions arising out of or
in connection with: (i) the premises; (ii) the condition of the premises, the
limits of such policy or policies to be in the amount of not less than
$300,000 per person and $1,000,000 per occurrence in respect of injury to
persons (excluding death), and in the amount of not less than $50,000 per
occurrence in respect to property damage or destruction, including loss of use
thereof.  All such policies shall be procured by Tenant from responsible
insurance companies satisfactory to Landlord.  Certified copies of such
policies, together with receipt evidencing of premiums therefor, shall be
delivered to Landlord prior to the commencement date of this lease.  Not less
than fifteen (15) days prior to the expiration date of any such policies,
certified copies of the renewals thereof (bearing notations evidencing the
payment of renewal premiums) shall be delivered to Landlord.  Such policies
shall further provide that not less than thirty (30) days written notice shall
be given to Landlord before such policy may be cancelled or changed to reduce
insurance provided thereby.

     (c)  If Tenant should last to comply with the foregoing requirements 
relating to insurances, Landlord may obtain such insurance, and Tenant shall 
pay to Landlord on demand, an additional rental hereunder, the premium cost 
thereof plus interest at the rate of ten per cent (10%) per annum from the 
date of payment by Landlord until repaid by Tenant.

     14.  CONDEMNATION

     (a)  If, during the term of this lease or any extension or renewal
thereof, all or a substantial part of the demised premises should be taken for
any public or quasi-public use under any governmental law, ordinance
regulations or by rights of eminent domain, or should be sold to the
condemning authority under threat of condemnation, this lease shall terminate
and the rent shall be abated during the unexpired portion of this lease,
effective from the date of taking of the demised premises by the condemning
authority.

     (b)  If less than a substantial part of the demised premises is taken for
public or quasi-public use under any governmental law, ordinance or regulation,
or by rights of eminent domain, or is sold to the condemnity authority under
threat of condemnation.  Landlord, as its option, may be written  notice
terminate this lease or shall forthwith as its sole expense restore and
reconstruct the buildings and improvements (other than leasehold improvements
made by Tenant or any assignee, subtenant or other occupant of the demised
premises) situated on the demised premises in order to make the same reasonably
tenantable and suitable for the uses for which the demised premises are leased
as defined in paragraph 3.  The rent payable hereunder during the unexpired
portion of this lease shall be adjusted equitably.

     (c)  Landlord and Tenant shall be entitled to receive and retain such
separate awards and portions of lump sum awards as may be allocated to their
respective interests in any condemnation proceedings.  The termination of this
lease shall not affect the rights of the respective parties to such awards.

     15.  HOLDING OVER:

     Should Tenant, or any of its successors in interest fail to surrender the
demised premises, or any part thereof, on the expiration of the term of this
lease, such holding over shall constitute a tenancy from month to month, at a
monthly rental equal to 150% of the rent paid for the last month of the term of
this lease unless otherwise agreed in writing.

     16.  DEFAULT BY TENANT:

     The following events shall be deemed to be events of default under this
lease:

     (a)  Failure of Tenant to pay any installment of the rent or other sum
payable to Landlord hereunder on the date that same is due and such failure
shall continue for a period of 10 days.

     (b)  Failure of Tenant to comply with any term, condition or covenant of
this lease, other than the payment of rent or other sum of money, and such
failure shall not be cured within 30 days after written notice thereof to
Tenant.

     (c)  Insolvency, the making of a transfer in fraud of creditors, or the
making of an assignment for the benefit of creditors by Tenant or any guarantor
of Tenant's obligations.

     (d)  Filing of a petition under any section or chapter of the United
States Bankruptcy Code, as amended, or under any similar law or statute of the
United States or any State thereof by Tenant or any guarantor of Tenant's
obligations or adjudication as a bankrupt or insolvent in proceedings filed
against Tenant or such guarantor.

     (e)  Appointment of a receiver or trustee for all or substantially all of
the assets of Tenant or any guarantor of Tenant's obligation hereunder.

     (f)  Abandonment by Tenant of any substantial portion of the demised
premises or cessation of the use of the use of the demised premises for the
purpose leased.

     17.  REMEDIES OF LANDLORD:

        Upon the occurrence of any of the events of default listed in Section
18.1 Landlord shall have the option to pursue any one or more of the following
remedies without any notice or demand whatsoever:

     (a)  Terminate this lease, in which event Tenant shall immediately
surrender the demised premises to Landlord.  If Tenant fails to so surrender
such premises.  Landlord may, without prejudice to any other remedy which it may
have for possession of the demised premises or arrearage in rent, enter upon
and take possession of the demised premises and expel or remove Tenant and any
other person who may be occupying such premises or any part thereof, by force
if necessary, without being liable for prosecution of any claim for damages
therefor.  Tenant shall pay to Landlord on demand the amounts of all loss and
damage which Landlord may suffer by reason of such termination, whether through
inability to relet the demised premises on satisfactory terms or otherwise.

     (b)  Enter upon and take possession of the demised premises, by force if
necessary, without terminating this lease and without being liable for
prosecution or for any claim for damage therefor, and expel or remove Tenant
and any other person who may be occupying such premises or any part thereof. 
Landlord may relet the demised premises and receive rent therefor.  Tenant
agrees to pay to Landlord monthly or on demand from time to time any deficiency
that may arise by reason of any such reletting.  In determining the amount of
such deficiency, the brokerage commission, attorneys' fees, remodeling expenses
and other costs of reletting shall be substracted from the amount of rent
received under such reletting.

     (c)  Enter upon the demised premises, by force, if necessary, without
terminating this lease and without being liable for any prosecution or for any
claim for damages therefor, and do whatever Tenant is obligated to do under
the terms of this lease.  Tenant agrees to pay Landlord on demand for expenses
which Landlord may incur in this effecting compliance with Tenant's obligations
under this lease, together with interest thereon at the rate of 10% per annum
from the date expended until paid.  Landlord shall not be liable for any
damages resulting to the Tenant from such action, whether caused by negligence
of Landlord or otherwise.

     Pursuit of any of the foregoing remedies shall not preclude pursuit of any
of the other remedies herein provided or any other remedies provided by law,
nor shall pursuit of any remedy herein provided constitute a forfeiture or
waiver of any rent due to Landlord hereunder or of any damages accruing to
Landlord by reason of the violation of any of the terms, conditions and
covenants herein contained.

     18.  LANDLORD'S LIEN:

     In addition to the statutory Landlord's lien, Tenant hereby grants to
Landlord a security interest to secure payment of all rent and other sums of
money becoming due hereunder from Tenant, upon all goods, wages, equipment,
fixtures, furniture and other personal property of Tenant situated in or upon
the demised premises, together with the proceeds from the sale or lease
thereof.  Such property shall not be removed without the consent of Landlord
until all arrangements in rent and other sums of money then due to Landlord
hereunder shall first have been paid and discharged.  Upon the occurrence of
any event of default, Landlord may, in addition to any other remedies
provided.


<PAGE>   5



herein or by law, enter upon the demised premises and take possession of any
and all goods, wares, equipments, fixtures, finances and other personal
property of Tenant situated on the premises without liability for trespass or
conversion, and sell the same or public or private sale, with or without having
such property at the sale, after giving Tenant reasonable notice of the time
and place of any such sale. Unless otherwise required by law, notice to Tenant
of such sale shall be deemed sufficient if given in the manner prescribed in
this lease at least 10 days before the time of the sale. Any public sale made
under this paragraph shall be deemed to have been conducted in a commercially
reasonable manner if held in the demised premises or where the property is
located, after the time, place and method of sale and a general description of
the types of property to be sold have been advertised in a daily newspaper
published in Dallas County, Texas, for five consecutive days before the date of
the sale. Landlord or its assigns may purchase at a public sale and, unless
prohibited by law, at a private sale. The proceeds from any dispusido deals
with in this paragraph, less any and all expenses connected with the making of
possession, holding and selling of the property (including reasonable
attorneys' fees and legal expenses), shall be applied as a credit against the
indebtedness secured by the security interest and granted herein. Any surplus
shall be paid to Tenant or as otherwise required by law: Tenant shall pay any
deficiencies forthwith. Upon request by Landlord, Tenant agrees to execute and
deliver to Landlord a financing statement in form efficient to perfect the
security interest of Landlord in the aforementioned property and proceeds the
rent under the provisions of the Business and Commerce Code in force in the
State of Texas. The valutory lien for rent is expressly reserved; the security
interest herein granted is in addition and supplementary thereto.

         19.      ATTORNEYS' FEES

         If, an account or any breach of default by landlord or Tenant of their
respective obligations under this lease, it shall become necessary for the other
to employ an attorney to enforce or defend any of its rights or remedies
hereunder and should such part prevail, it shall be entitled to any reasonable
attorneys' fees incurred in such commission.

         20.      QUIET ENJOYMENT.

         Landlord warrants that it has full right and power to execute and
perform this lease and to grant the estate demised herein and that Texas, on
payment of rent and performing the covenants herein contained, shall peaceably
and quietly have, hold and enjoy the demised premises during the full term of   
this lease and any extension or renewal hereof; provided, however, that Tenant
accepts this lease subject and subordinate to any surrendered mortgage, deed of
trust or other presently existing upon the demised premises. Landlord is hereby
irrevocably vested with full power and authority to subordinate Tenant's
interest hereunder to any mortgage, deed of trust or other lien hereafter
placed on the demised premises, and Tenant agrees upon demand to execute such
further instruments subordinating this lease as Landlord may request, provided
such farther subordination shall be upon the express condition that this lease,
shall be recognized by the mortgage and that the rights of Tenant shall remain
in full force and effect during the term of this lease so long as Tenant shall
continue to perform all of the covenant of this lease.

         21.      WAIVER OF DEFAULT

         No waiver by the parties hereto of any default or breach of any term,
conditions or covenant of this lease shall be deemed to be waiver of any
subsequent default or breach of the same or any other term, condition or
covenant contained herein.

         22.      PROFESSIONAL SERVICE FEES:

         23.      CERTIFICATE OF OCCUPANCY:

         Tenant may, prior to the commencement of the term of this lease apply
for a Certificate of Occupancy to be issued by the municipality in which the
demised premises are located. Nothing herein contained shall obligate Landlord
to install any additional electrical wiring, plumbing or plumbing fixtures where
are not presently existing in the demised premises, or which have not been
expressly agreed upon by Landlord in writing.

         24.      FORCE MAJEURE:

         In the event performance by Landlord of any term, condition or covenant
in this lease is delayed or prevented by any Act of God, strike, lookout,
shortage of material or labor reaction by any governmental authority, civil
riot, flood, and any other cause not within the control of Landlord, the period
for performance of such term, condition or covenants shall be extended for a
period equal to this period Landlord is to delayed or hindered.

         25.      EXHIBITS

         All exhibits, attachments, annexed instruments and addenda referred to
herein shall be considered a part hereof for all purpose with the same force and
effect as if copied as full length herein.

<PAGE>   6
     26.  USE OF LANGUAGE:

     Words of any gender used in this lease shall be held and construed to
include any other gender, and words in the singular shall be held to include
the plural unless the context otherwise requires.

     27.  CAPTIONS:

     The captions or headings of paragraphs in this lease are inserted for
convenience only and shall not be considered in construing the provisions
hereof if any question of intent should arise.

     28.  SUCCESSORS:

     The terms, conditions and covenants contained in this lease shall apply
to, inure to the benefit of, and be binding upon the parties hereto and their
respective successors in interest and legal representatives except as otherwise
herein expressly provided.  All rights, powers, privileges, immunities and
duties of Landlord under this lease, including, but not limited to, any notices
required or permitted to be delivered by Landlord to Tenant hereunder, may, at
Landlord's option, be exercised or performed by Landlord's agent or attorney.

     29.  SUBLEASE:

     If this lease is in fact a sublease, Tenant accepts this lease subject to
all of the terms and conditions of the lease under which Landlord holds the
demised premises as lessee.  Tenant covenants that it will do no act or thing
which would constitute a violation by Landlord of its obligation under such
lease.

     30.  SEVERABILITY:

     If any provision in this lease should be held to be invalid or
unenforceable, the validity and enforceability of the remaining provisions of
this lease shall not be affected thereby.

     31.  NOTICES:

     Any notice or document required or permitted to be delivered hereunder may
be delivered in person or shall be deemed to be delivered, whether actually
received or not, when deposited in the United States mail, postage prepaid,
registered or certified mail, return receipt requested, addressed to the
parties at the addresses indicated below, or at such other addresses as may
have theretofore been specified by written notice delivered in accordance
herewith.

LANDLORD:     DALLAS PATHOLOGY LEASING           TENANT:  UNIPATH, LTD.
              ------------------------                    -------------
              4350 Alpha Road                             4350 Alpha Road
              ---------------                             ---------------
              Dallas, TX  75244                           Dallas, TX  75244
              -----------------                           -----------------

PRINCIPAL BROKER:  None
                   -------------------

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

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

     32.  SPECIAL CONDITIONS:  None

        

     EXECUTED the _________ day of May, 1995 __________________,19__,

ATTEST:

                                        LANDLORD:  DALLAS PATHOLOGY LEASING
-------------------------------------              ----------------------------
                                                   By  J. Sloan Leonard
                                                   ----------------------------
-------------------------------------              Title  President


ATTEST:                              
                                      
                                      
-------------------------------------   TENANT:    UNIPATH, LTD.
                                                   ----------------------------

                                                   ----------------------------
                                                   By
-------------------------------------              ----------------------------
By                                                 Title

-------------------------------------              ----------------------------
Title                                              By

                                                   ----------------------------
                                                   Title

------------------------------------    ---------------------------------------
By                                      By



<PAGE>   7
                                     
                                 EXHIBIT "A"


     "RENEWAL OPTION:  Provided that at the end of the primary term of this
lease Tenant not be in default of any term, condition or covenant contained in
this lease.  Tenant (but not any assignee of subtenant) shall have the right
and option to renew this lease, by written notice delivered to Landlord with a
copy of the Principal Broker no later than 180 days prior to the expiration of
the primary term, for the additional term of five (5) years, under the same
terms, conditions, and covenants contained herein, except:

     A.  The rental rate for the renewal term shall be $7.15 per square foot,
just do or $9,521.42 per month.
                                      




















                                             INITIALED:

                                             LANDLORD  -----------------------
                                             TENANT --------------------------
