Exhibit 10.2.4

                                  GUARANTY AGREEMENT


    For the sum of $100.00 and other good and valuable consideration, the
receipt of which is hereby acknowledged, and in order to induce Jefferson
County, Arkansas (herein referred to as "LENDER") to loan TSI Redfield
Laboratories, Inc.("BORROWER"), Three Hundred Fifty Thousand and  No/100 Dollars
($350,000.00), said loan being evidenced by the Borrower's Promissory Note of
even date herewith ("Note"), the undersigned hereby unconditionally guarantees
to Lender the prompt and punctual performance of each and every agreement,
covenant and condition contained in the Note, security documents, and the Loan
Agreement ("Agreement") provided, however, that except as otherwise provided
herein, this Guaranty and the liability assumed hereunder is limited in amount
to the unpaid principal and accrued interest and other costs and expenses
provided for in the Note and the Agreement, and that said amount will be
promptly paid in full when due in accordance with the provisions of the Note or
the Agreement whether at maturity, by acceleration or otherwise, all at the
times and places and at the rate and currency described in the Agreement and the
Note and otherwise in accordance therewith.  This Guaranty shall terminate upon
payment of the amounts set forth above and the fulfillment of those terms,
covenants, and conditions contained within the documents evidencing and securing
this loan transaction which are referred to above, including, but not limited
to, those indemnification covenants dealing with the disposition, generation,
storage or usage of hazardous materials and any liability which

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arises therefrom contained within Paragraph 24 of the Loan Agreement.

    This is an unconditional and absolute Guaranty, limited only in amount as
mentioned above, of payment and performance, and if for any reason, any duty,
agreement or obligation of the Borrower contained in the Note or the Agreement
shall not be performed or observed by the Borrower, or if any amount or any part
thereof payable under or in connection with the Note or the Agreement shall not
be paid promptly when due and payable, the undersigned will promptly perform or
cause to be performed each of such duties, agreements and obligations and will
forthwith pay such amounts to the Lender or any subsequent holder of the Note,
regardless of any defense or setoff or counterclaim which the Borrower may have
or assert, and regardless of whether any holder of the Note or anyone on behalf
of such holder shall have instituted any suit, action or proceeding or exhausted
its remedies or taken any steps to enforce any rights against the Borrower or
any other person to compel any such performance or to collect all or part of any
such amounts, either pursuant to the provisions of the Note and the Agreement or
at law or in equity, and regardless of any other condition or contingency.

    The undersigned hereby: (i) waives any requirement that the Lender or any
subsequent holder of the Note, in the event of a default by the Borrower, first
make demand upon or seek to enforce remedies against the Borrower before
demanding payment under or
seeking to enforce the Guaranty; (ii) covenants that this Guaranty

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 will not be discharged except by complete performance of the obligations 
contained in the Note and the Agreement; (iii) agrees that this Guaranty 
shall remain in full force and effect without regard to, and shall not be 
affected or impaired, without limitation, by any invalidity, irregularity or 
unenforceability in whole or in part of the Note or the Agreement or any 
limitation on the liability of the Borrower thereunder or any limitation on 
the method or terms of payment thereunder which may now or hereafter be 
caused or imposed in any manner whatsoever; and (iv) consents and agrees that 
Lender, or its successors and assigns, may at any time, either with or 
without consideration, release and/or surrender any property or interest 
therein or other security of any kind held by it or on its behalf securing 
any indebtedness or liability covered hereby, or substitute for any 
collateral so held by it any other collateral, or modify, renew, or extend 
the terms of the Note or other Agreement without notice to or further consent 
from undersigned, and such surrender, substitution, modification, renewal, or 
extension shall not in any way affect the liability of the undersigned.  The 
undersigned hereby unconditionally waives diligence, presentment, protest, 
and any notice of default in the payment of any amount at any time payable by 
the Borrower under or in connection with the Note or the Agreement and notice 
of the breach or nonperformance of any duty, agreement or obligation of the 
Borrower contained in the Note or in the Agreement.

    The obligations, covenants, agreements and duties of the undersigned under
this Guaranty shall not be affected or impaired

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by any assignment or transfer, in whole or in part, of the Note with or 
without notice to the undersigned or any waiver by the holder or holders of 
the Note of the performance or observance by the Borrower of any of the 
agreements, covenants, terms or conditions contained in the Note or in the 
Agreement; or any indulgence in or the extension of the time for the payment 
by the Borrower of any amounts payable under or in connection with the Note 
or Agreement; or of the time of performance by the Borrower of any other 
obligation under or arising out of the Note or the Agreement; or the 
extension or renewal thereof, or the modification or amendment of any duty, 
agreement or obligation of the Borrower set forth in the Note or the 
Agreement; or the voluntary or involuntary liquidation, sale, or other 
disposition of all or substantially all of the assets of the Borrower, or 
receivership insolvency, bankruptcy, reorganization or other similar 
proceedings affecting the Borrower or any of its assets; or the release or 
discharge of the Borrower from the performance or observance of any 
agreement, covenant, term or condition contained in the Note or the Agreement 
without the consent of the Lender or any such holder of the Note; or the 
merger of the Borrower; or any other cause, whether similar or dissimilar to 
the foregoing, including the release of any other guarantor of the Note and 
Agreement; or the release of any other collateral securing said loan; nor 
shall the Lender have any obligation to commence proceedings and enforce any 
other guaranty of the Note prior to exercising its rights against the 
undersigned.

    This Guaranty may not be amended or modified except by written agreement
executed by the undersigned with the consent in writing of the Lender or any
subsequent holder of the Note.

    All the covenants, agreements, terms and conditions in this Guaranty
contained herein shall bind and inure to the benefit of the undersigned, heirs,
administrators and assigns, and the respective holders of the Note.

    This Guaranty shall, for all purposes, be construed in accordance with and
governed by the law of the State of Arkansas. Undersigned hereby waives any
defense arising from lack of and otherwise specifically consents to in personam
jurisdiction within any state or federal court sitting in the State of Arkansas
having subject matter jurisdiction over any cause of action arising under, as a
result of, or because of the loan referenced herein and/or this Guaranty
Agreement.   Undersigned shall not, until the prior payment in full of the Note,
assert, enforce or otherwise exercise a) any right of subrogation to any of the
rights or liens of Lender, its successors or assigns, or any other beneficiary
against Borrower or any other obligor on the indebtedness or obligations covered
hereby or any collateral or other security, or b) any right of recourse,
reimbursement, contribution, indemnification, or similar right against Borrower
of any other obligor on all or any part of the indebtedness or obligations
covered hereby or any guarantor thereof, and, until the prior payment in full of
the Note, undersigned hereby irrevocably waives any and all of the foregoing
rights.  Undersigned irrevocably waives the benefit of,

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and right to participate in, any collateral or other security given to 
Lender, its successors and assigns or any other beneficiary to secure payment 
of the indebtedness and other obligations hereunder.

    IN WITNESS WHEREOF, the undersigned has executed this Guaranty this 22nd
day of May, 1997.

                        GENZYME TRANSGENICS CORPORATION



                        By:  /s/ John B. Green 
                             ------------------------ 
                        Title:  Vice President 
                                ---------------------

                                    
                                    ACKNOWLEDGMENT

STATE OF Arkansas  )
                   ) ss:
COUNTY OF Pulaski  )


    Before me, the undersigned Notary Public, duly qualified and commissioned
for the State and City/County aforesaid, appeared John B. Green the Vice
President of Genzyme Transgenics Corporation, who stated that he has executed
the foregoing for and on behalf of the corporation for the consideration, uses
and purposes therein stated and set forth.

    DATED this 22nd day of May, 1997.


                                   /s/ John Kooistra 
                                   -------------------
                                  Notary Public

My Commission Expires:

 09-30-01 
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