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                                                                   EXHIBIT 10.61




                              REVOLVING CREDIT NOTE

$4,000,000.                    CHICAGO, ILLINOIS                OCTOBER 24, 1997

     FOR VALUE RECEIVED, ACCUMED INTERNATIONAL, INC., a DELAWARE corporation
having its chief executive office and principal place of business at 900 N.
FRANKLIN STREET, SUITE 401, CHICAGO, ILLINOIS 60610 (the "Borrower"), hereby
unconditionally and absolutely promises to pay to the order of TRANSAMERICA
BUSINESS CREDIT CORPORATION, a Delaware corporation (the "TBCC"), on the
Maturity Date, at TBCC's office at 9399 West Higgins Road, Suite 600, Rosemont,
Illinois 60018, or at such other location as TBCC may from time to time
designate, in lawful money of the United States of America and in immediately
available funds, the principal amount equal to $4,000,000 or such greater or
lesser amount as represents the aggregate unpaid principal amount of all Loans
made by TBCC to the Borrower pursuant to the Loan and Security Agreement between
TBCC and Borrower dated OCTOBER 24, 1997 (the "Loan Agreement"). The Borrower
further promises to pay interest in like money and funds at TBCC's office
specified above (or at such other location as TBCC may from time to time
designate) on the unpaid principal amount hereof from time to time outstanding
from and including the date hereof until paid in full (both before and after
judgment) at the rates and on the dates set forth in the Loan Agreement. All
capitalized terms used herein which are not defined herein shall have the
meanings ascribed to such terms in the Loan Agreement.

     The holder of this Note is authorized to record the date and amount of each
Loan evidenced by this Note, the date and amount of each payment or prepayment
of principal hereof and the interest rate with respect thereto on a schedule
attached hereto, or on a continuation of such schedule attached hereto and made
a part hereof, and any such notation shall be conclusive and binding for all
purposes absent manifest error; provided, however, that the failure of TBCC to
make any such recordation or endorsement shall not affect the obligations of the
Borrower hereunder or under the Loan Agreement.

     Whenever any payment to be made hereunder shall be stated to be due on a
day that is not a Business Day, the payment may be made on the next succeeding
Business Day and such extension of time shall be included in the computation of
the amount of interest due hereunder.

     This Note is entitled to the benefit of all terms and conditions of, and
the security of all security interests, liens, mortgages, deeds of trust and
rights granted pursuant to, the Loan Agreement and the other Loan Documents, and
is subject to optional and mandatory prepayment as provided therein.

     Upon the occurrence of any one or more Events of Default, all amounts then
remaining unpaid on this Note may be declared to be or may automatically become
immediately due and payable as provided in the Loan Agreement.

     The Borrower acknowledges that the holder of this Note may assign, transfer
or sell all or a portion of its rights and interests to and under this Note to
one or more Persons as provided in the Loan Agreement and that such Persons
shall thereupon become vested with all of the rights and benefits of TBCC in
respect hereof as to all or that portion of this Note which is so assigned,
transferred or sold.



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     In the event of any conflict between the terms hereof and the terms and
provisions of the Loan Agreement, the terms and provisions of the Loan Agreement
shall control.

     The Borrower and all other parties that at any time may be liable hereupon
in any capacity, jointly or severally, waive presentment, demand for payment,
protest and notice of dishonor of this Note and authorize the holder hereof,
without notice, to increase or decrease the rate of interest on any amount owing
under this Note in accordance with the Loan Agreement. The Borrower further
waives promptness, diligence, notice of acceptance and any other notice with
respect to any of the Obligations and any requirement that TBCC exhaust any
rights or take any action against any other Person or any collateral. The
Borrower further hereby waives notice of or proof of reliance by TBCC upon this
Note, and the Obligations shall conclusively be deemed to have been created,
contracted, incurred, renewed, extended, amended or waived in reliance upon this
Note. The Borrower shall make all payments hereunder and under the Loan
Agreement without defense, offset or counterclaim. No failure to exercise and no
delay in exercising any rights hereunder on the part of the holder hereof shall
operate as a waiver of such rights. This Note may not be changed orally, but
only by an agreement in writing, which is signed by the party or parties against
whom enforcement of any waiver, change, modification or discharge is sought.

     THE VALIDITY, INTERPRETATION AND ENFORCEMENT OF THIS NOTE AND THE OTHER
LOAN DOCUMENTS AND ANY DISPUTE ARISING OUT OF OR IN CONNECTION WITH THIS NOTE,
WHETHER SOUNDING IN CONTRACT, TORT, EQUITY OR OTHERWISE, SHALL BE GOVERNED BY
THE INTERNAL LAWS (AS OPPOSED TO THE CONFLICTS OF LAW PROVISIONS) AND DECISIONS
OF THE STATE OF ILLINOIS.

     ALL DISPUTES ARISING UNDER OR IN CONNECTION WITH THIS NOTE AND ANY OTHER
LOAN DOCUMENT BETWEEN THE BORROWER AND THE TBCC, WHETHER SOUNDING IN CONTRACT,
TORT, EQUITY OR OTHERWISE, SHALL BE RESOLVED ONLY BY STATE AND FEDERAL COURTS
LOCATED IN CHICAGO, ILLINOIS, AND THE COURTS TO WHICH AN APPEAL THEREFROM MAY BE
TAKEN; PROVIDED, HOWEVER, THAT THE TBCC SHALL HAVE THE RIGHT, TO THE EXTENT
PERMITTED BY APPLICABLE LAW, TO PROCEED AGAINST THE BORROWER OR ITS PROPERTY IN
ANY LOCATION REASONABLY SELECTED BY THE TBCC IN GOOD FAITH TO ENABLE THE TBCC TO
REALIZE ON SUCH PROPERTY, OR TO ENFORCE A JUDGMENT OR OTHER COURT ORDER IN FAVOR
OF THE TBCC. THE BORROWER AGREES THAT IT WILL NOT ASSERT ANY PERMISSIVE
COUNTERCLAIMS, SETOFFS OR CROSS-CLAIMS IN ANY PROCEEDING BROUGHT BY THE TBCC.
THE BORROWER WAIVES ANY OBJECTION THAT THE BORROWER MAY HAVE TO THE LOCATION OF
THE COURT IN WHICH THE TBCC HAS COMMENCED A PROCEEDING, INCLUDING, WITHOUT
LIMITATION, ANY OBJECTION TO THE LAYING OF VENUE OR BASED ON FORUM NON
CONVENIENS.

     THE BORROWER HEREBY IRREVOCABLY DESIGNATES CT CORPORATION SYSTEM, 1209
ORANGE STREET, WILMINGTON, DELAWARE 19801 AS THE DESIGNEE AND AGENT OF THE
BORROWER TO RECEIVE, FOR AND ON BEHALF OF THE BORROWER SERVICE OF PROCESS IN ANY
LEGAL ACTION OR PROCEEDING WITH RESPECT TO THIS NOTE OR ANY OTHER LOAN DOCUMENT.
IT IS UNDERSTOOD THAT A COPY OF SUCH PROCESS SERVED ON SUCH AGENT AT ITS ADDRESS
WILL BE PROMPTLY FORWARDED BY MAIL TO THE BORROWER,



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BUT THE FAILURE OF THE BORROWER TO RECEIVE SUCH COPY SHALL NOT AFFECT IN ANY WAY
THE SERVICE OF SUCH PROCESS. NOTHING HEREIN SHALL AFFECT THE RIGHT OF THE TBCC
TO SERVE LEGAL PROCESS IN ANY OTHER MANNER PERMITTED BY LAW.

     THE BORROWER AND, BY ITS ACCEPTANCE HEREOF, THE TBCC EACH HEREBY WAIVE THE
RIGHT TO TRIAL BY JURY IN ANY ACTION OR PROCEEDING BASED UPON, ARISING OUT OF,
OR IN ANY WAY RELATING TO: (I) THIS NOTE; OR (II) ANY OTHER PRESENT OR FUTURE
INSTRUMENT OR AGREEMENT BETWEEN TBCC AND BORROWER; OR (III) ANY CONDUCT, ACTS OR
OMISSIONS OF TBCC OR BORROWER OR ANY OF THEIR DIRECTORS, OFFICERS, EMPLOYEES,
AGENTS, ATTORNEYS OR ANY OTHER PERSONS AFFILIATED WITH TBCC OR BORROWER; IN EACH
OF THE FOREGOING CASES, WHETHER SOUNDING IN CONTRACT OR TORT OR OTHERWISE.

                                        ACCUMED INTERNATIONAL, INC.


                                        By:_____________________________________
                                           Leonard R. Prange, Chief Operating
                                           Officer and Chief Financial Officer



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                                    SCHEDULE
                            TO REVOLVING CREDIT NOTE
                             DATED OCTOBER __, 1997
                        OF ACCUMED INTERNATIONAL, INC. TO
                    TRANSAMERICA BUSINESS CREDIT CORPORATION


Date      Amount of   Interest Rate    Amount of       Unpaid     Notation
----      ---------   -------------    ---------       ------     --------
            Loan                     Principal Paid  Principal    Made by
            ----                     --------------  ---------    -------
                                                      Balance
                                                      -------







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