EXHIBIT 4.3


Applied NeuroSolutions, Inc.
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David Ellison                                        50 Lakeview Parkway
Chief Financial Officer and Controller               Suite 111
                                                     Vernon Hills, IL 60061
                                                     847-573-8025  Ext. 239
                                                     847-573-8030  (FAX)
                                                     ellison@appns.com
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January 20, 2004

Dear Applied NeuroSolutions, Inc. Convertible Promissory Note Holder,

         During the past eighteen months you invested in Applied NeuroSolutions,
Inc. (and predecessor companies) by purchasing a 6% Convertible Promissory Note
(the "Note"). The terms of conversion of the Note were as follows:

            o     Upon closing of a minimum of $3 million in a future placement,
                  the Note, plus accrued interest, will automatically convert
                  into shares of APNS Common Stock at a conversion price equal
                  to 50% of the per share price of the Common Stock sold in the
                  future placement. The conversion price will not exceed $0.15
                  per share.

         As you are aware, we are currently in the process of raising
approximately $6 million in a private placement ("the Placement"). A lead
investor (the "Investor") has approached us and agreed to invest $1.5 million in
the Placement, subject to certain conditions. One of the conditions is a change
in the conversion rate (as described below) for the Note holders. The suggested
change in the conversion is as follows:

            o     The Note will be converted into units to be sold in the
                  private placement (a unit is being sold for $0.25 and consists
                  of one share of common stock and a warrant to purchase one
                  share of common stock. The warrant is exercisable for 5 years
                  and has an exercise price of $0.30). In addition, the Note
                  holder will receive additional warrants equal to 10% of the
                  units purchased.

         As an example, based on the unit price of $0.25 in the Placement,
$100,000 of convertible debt (including accrued interest) will be converted into
400,000 shares of Common Stock and 440,000 warrants (400,000 warrants plus 10%
or 40,000). The warrants will have an exercise price of $0.30 per share.

         Management and the Board of Directors of APNS have reviewed the
proposal from the Investor and believe that, based on the funds committed from
the Investor and additional funds that have been committed from other investors
as a result of the Investor, it is in the best interests of the Note holders to
consent to this change in the terms of the conversion. Management believes that
the Investor proposal represents the Company's best chance to survive, and
thereafter, to enhance the value of our science in the marketplace and continue
our scientific progress. This consent to change the terms of the conversion is
contingent upon the Placement closing on its minimum offering ($6 million) with
the Investor described above. If any other minimum $3 million funding (excluding
the Investor) is completed prior to conversion, the original conversion terms
will apply.

<PAGE>


PLEASE BE AWARE THAT WE ARE  OPERATING  WITHIN A VERY TIGHT  TIME  SCHEDULE  AND
ACCORDINGLY WOULD GREATLY  APPRECIATE IF YOU WOULD REVIEW THIS INFORMATION,  AND
IF THE INFORMATION IS ACCEPTABLE,  PLEASE SIGN THE ENCLOSED  NOTEHOLDER  CONSENT
AND RETURN BY FAX TO ME AT THE COMPANY AT (847)  573-8030,  WITH ORIGINALS TO BE
RETURNED TO THE COMPANY ADDRESS.

TO REITERATE,  IF OUR COMPANY DOES NOT RECEIVE THE  NECESSARY  CONSENTS FROM THE
NOTEHOLDERS,  THE CONTEMPLATED OFFERING WILL NOT TAKE PLACE AND THE COMPANY WILL
LIKELY BE FORCED TO CEASE OPERATIONS.

         By signing and sending to us the  consent  below,  you agree to the new
conversion  terms.  This is a very  important  time  for our  Company,  and your
assistance in these matters is greatly appreciated. We appreciate your continued
involvement with APNS. If you have any questions,  please call me at (847) 573 -
8025 extension 239.

                                                    Sincerely,


                                                    David Ellison
                                                    Chief Financial Officer


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The undersigned Convertible Promissory Note holder of Applied NeuroSolutions,
Inc. hereby consents to the following change in the conversion rate as stated in
the Convertible Promissory Note:

         The Convertible Promissory Note, including accrued interest, will be
automatically converted upon APNS completing a minimum funding of $6 million.
The conversion rate will be at the unit purchase price of the Placement (as
described above) to be closed in the first quarter of 2004. The convertible
promissory note holder will be entitled to additional 10% warrant coverage to
purchase shares of APNS common stock at an exercise price equal to the exercise
price of the warrants included in the unit sold in the Placement. The unit is
expected to be sold at $0.25 per unit and consist of one share of Common Stock
and one warrant, exercisable for 5 years, at an exercise price of $0.30. The
consent and change in terms of the conversion provisions is contingent upon a
closing of the Placement that includes the Investor (as described above).


I consent to the change in the terms of my Convertible Promissory Note:


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Signature


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Convertible Promissory Note Holder                   Date