ASSIGNMENT FOR SECURITY

                                  (TRADEMARKS)

STATE OF GEORGIA  )

                  )  SS.:

COUNTY OF FULTON  )

                  WHEREAS,   EDITEK,   INC.,   a   Delaware   corporation   (the
"Assignor"), has adopted, used and is using marks which are either registered or
applied for in the United  States  Patent and  Trademark  Office as set forth on
Exhibit A (the "Trademarks"), and

                  WHEREAS,  the Assignor is the sole owner of the entire  right,
title  and  interest  in and to the  Trademarks  which  are  registered  and the
goodwill of the business  symbolized  by the  Trademarks  and the  registrations
thereof, and

                  WHEREAS,  Assignor  has  entered  into that  certain  Loan and
Security  Agreement,  dated of even date (as amended,  supplemented  or restated
from time to time,  the "Loan  Agreement"),  between  Assignor,  certain  of its
affiliates and HELLER FINANCIAL,  INC., a Delaware corporation  ("Lender"),  and
Lender  has, on the date  hereof,  made  certain  loans to or for the benefit of
Assignor and may make additional loans to or for the benefit of Assignor, and

                  WHEREAS,  pursuant  to the Loan  Agreement  and as a condition
precedent to the extension of the financial accommodations to or for the benefit
of the Assignor under the Loan  Agreement,  the Assignor has agreed to assign to
Lender  and to  grant  to  Lender  a  continuing  security  interest  in,  and a
continuing  lien on, all of the Assignor's  right,  title and interest in and to
the following (collectively the "Trademark Collateral"),

                  (a)  the Trademarks, together with all  rights,  benefits  and

         privileges  derived  therefrom,  and the goodwill   of   the   business
         symbolized  by the  Trademarks   and  the  registrations  thereof,  and

                  (b)  all proceeds thereof, including, but not limited to, any

         claims and demands  arising out of any  infringement of the Trademarks,
         including  the right to settle  disputes  concerning  such  claims  and
         demands.

                  NOW,  THEREFORE,  in order to induce Lender to consummate  the
financial accommodations to the Assignor provided for in the Loan Agreement, and
for other good and valuable consideration,  receipt and sufficiency of which are
hereby  acknowledged,  the  Assignor  does hereby  assign to Lender and grant to
Lender a continuing  security  interest in and a continuing  lien on, the entire
right,  title and interest of Assignor in and to the Trademark  Collateral.  



The Trademark  Collateral  shall  serve as  collateral  security  to Lender  
for the payment and  performance of the  Obligations (as such term is defined 
in the Loan Agreement)and  shall constitute a part of the Collateral (as such 
term is defined in  the  Loan  Agreement), and  shall  be  subject to all of 
the terms and  conditions  of  the  Loan Agreement,  which is incorporated 
herein by reference.

                  Unless and until said lien and security interest is foreclosed
upon,  Assignor  (i) shall be deemed to  remain  in  exclusive  and  undisturbed
possession  of the  Trademarks,  (ii)  shall  exclusively  retain  all rights to
license others under the  Trademarks,  but only in a manner  consistent with the
preservation of their current substance, validity, registration and the security
interest  granted herein,  and (iii) may bring suit for the  infringement of the
Trademarks  and to retain the  proceeds  of the  foregoing.  Lender  need not be
joined as a plaintiff in any such infringement suit; provided, that should it be
necessary,  in Lender's sole judgment, that Lender be joined as an indispensable
party or true party in interest in any such infringement  suit, Lender shall, at
its option, either

                  (1) appoint  Assignor  its attorney in fact for the purpose of
         prosecuting  such  infringement  suit  on the  express  condition  that
         Assignor  indemnify and hold Lender harmless for any liability incurred
         by Lender as a result of such appointment, or

                  (2) participate actively in the prosecution of such suit.

                  Assignor  further  agrees  (i)  that  while  a  secured  party
hereunder,  Lender  shall have no  obligation  or  responsibility  to protect or
defend the Trademark  Collateral and Assignor shall at its own expense  protect,
defend  and  maintain  the  same  to the  extent  reasonably  advisable  for its
business, (ii) to use its best efforts to detect any infringers of the Trademark
Collateral, to forthwith advise Lender in writing of infringements detected, and
protect, defend and maintain the Trademark Collateral against any infringements,
(iii) that if Assignor fails to comply with the foregoing  clauses (i) and (ii),
Lender  may do so in  Assignor's  name or in  Lender's  name  but at  Assignor's
expense,  and  Assignor  hereby  agrees to  reimburse  Lender for all  expenses,
including  reasonable   attorneys'  fees,  incurred  by  Lender  in  protecting,
defending and maintaining the Trademark  Collateral owned by Assignor,  and (iv)
to use the Trademarks only in its businesses as they are presently conducted.

                  The  security  interest in the  Trademark  Collateral  granted
hereunder  shall  remain  in full  force  and  effect  until  the  later  of the
termination  of the Loan Agreement and the payment and  satisfaction  in full of
the Obligations.  At any time thereafter Lender shall, if requested by Assignor,
execute  and  deliver  to  Assignor,   or  to  a  third  party  upon  Assignor's
instructions,  for filing with the United States Patent and Trademark Office and
in each  office  in which  any  financing  statement  relative  to the  security
interest  granted hereby may have been filed,  (i)  documentation  in accordance
with the rules and regulations of said office, (ii) termination statements under
the  Uniform  Commercial  Code and  (iii)  any  other  documentation  reasonably
requested by Assignor,  all as may be necessary to release Lender's  interest in
the Trademark Collateral, and all at the cost and expense of Assignor.

                                           -2-




                  IN WITNESS WHEREOF, the Assignor has caused this Assignment to
be duly executed by its authorized officer or agent as of January ___, 1996.



                                                  EDITEK, INC.      

                                                  By:

                                                  Title:

                                                  Attest:

                                                  Title:

                                                         [CORPORATE SEAL]


STATE OF GEORGIA  )

                  )  ss.:

COUNTY OF FULTON  )

                  On this ___ day of January,  1996,  before me personally  came
___________________  and  _____________________,  to me known,  who, being by me
duly   sworn,   did   depose   and  say  that   they  are,   respectively,   the
____________________and  _____________________  of EDITEK, INC., the corporation
described herein and which executed the foregoing instrument; that they know the
seal of said  corporation;  that the seal  affixed  to said  instrument  is such
corporate  seal;  that it was so affixed by order of the Board of  Directors  of
said corporation and that they signed thereto by like order.

                                               Sworn to and subscribed before me
                                               this ___ day of January, 1996.

                                               Notary Public

                                                     [NOTARIAL SEAL]

                                    -3-


                                               My Commission Expires:


                                      -4-



                                    EXHIBIT A


       TRADEMARK          REGISTRATION NUMBER     REGISTRATION DATE

EDITEK                          1,879,044              02/14/95

BIOMAN                            363,506              11/10/89

LOGO                            1,374,423              12/10/85

QUIK-CARD                       1,387,168              03/25/86

EZ-SCREEN                       1,412,788              10/14/86

DAIRISCREEN                     1,629,710              01/01/91

DAIRYSCREEN                     1,629,709              01/01/91

VERDICT                         1,771,281              05/18/93

PREDICT                         1,877,141              01/31/95

RECON                           1,847,306              07/26/94

EZ-QUANT                        1,917,508              09/12/95