Document:

<PAGE>
                             FIRST AMENDMENT TO THE
                             ----------------------
                 MANOR CARE, INC. SENIOR MANAGEMENT SAVINGS PLAN
                 -----------------------------------------------
                             FOR CORPORATE OFFICERS
                             ----------------------

In exercise of the powers and authority conferred upon and reserved to the Board
of Directors of Manor Care, Inc. under and by virtue of Article VIII of the
Manor Care, Inc. Senior Management Savings Plan For Corporate Officers, the
Board hereby amends said Plan in the manner and to the extent set forth herein:

1.       Section 2.19 and 2.20 of the Plan are renumbered 2.20 and 2.21
         respectively. A new Section 2.19 is added to the Plan to read as
         follows:
         "2.19    "Retirement" means the termination of employment with the
                  Company for reasons other than death after a Participant has
                  attained age 65 or has attained age 55 or older with ten or
                  more years of service with the Company."

2.       Section 7.02 of the Plan is amended to read as follows:
         "7.02.   The entire amount credited to a Participant's Accounts shall
                  become payable upon termination of the Participant's
                  employment with the Company by reason of his death, total and
                  permanent disability, or Retirement. The nonforfeitable,
                  vested portion of a Participant's Accounts shall become
                  payable upon termination of the Participant's employment with
                  the Company for any other reason. Amounts so payable shall be
                  paid to the Participant at the election of the Participant in
                  cash or in shares of Manor Care, Inc. common stock, or a
                  combination thereof, in a lump sum payment as soon as
                  practicable after such termination of employment, but in no
                  event later than January 31 of the following year. However, at
                  least one year prior to his Retirement, the Participant may
                  make an irrevocable election to delay receiving his benefits
                  from the Plan to a date specific on or before the Participant
                  attains age 65. In addition, at least one year prior to his
                  Retirement, the Participant may make an irrevocable election
                  to receive his benefits in

                                      -1-
<PAGE>

                  installment payments. If a Participant elects distribution in
                  the form of installment payments, he shall further designate
                  the commencement date and period of time (not to exceed ten
                  years) over which the installment payments are to be made.
                  Such installment payments shall be made on an annual basis in
                  the month of January commencing the first January following
                  the Participant's Retirement. During the period such
                  installment payments are being made, the remaining balances in
                  the Participant's Accounts shall continue to be credited with
                  earnings or losses in accordance with the provisions of
                  Article VI of the Plan. For purpose of a Participant who is
                  retiring in 2001, such election must be given to the CEO on or
                  before December 31, 2001."

3.       Appendix A, List of Covered Officers, attached hereto, has been revised
         as of September 1, 2000.

4.       The amendments set forth in this First Amendment to the Manor Care,
         Inc. Senior Management Savings Plan for Corporate Officers shall be
         effective January 1, 2001 unless otherwise stated.

5.       The Manor Care, Inc. Senior Management Savings Plan for Corporate
         Officers, as amended, shall continue in full force and effect.

IN WITNESS WHEREOF, the Board of Directors of Manor Care, Inc. has caused this
First Amendment to the Manor Care, Inc. Senior Management Savings Plan for
Corporate Officers to be executed by its duly authorized officers as of the 1st
day of January, 2001.

                             MANOR CARE, INC.

                             By  /s/ Paul A. Ormond
                                 ------------------------------------------
                                 President and Chief Executive Officer

ATTEST:

                                      -2-
<PAGE>

By /s/ R. Jeffrey Bixler
   ----------------------------------
     Secretary

                                      -3-
<PAGE>

                                   APPENDIX A
                                   ----------

                                MANOR CARE, INC.
                         SENIOR MANAGEMENT SAVINGS PLAN
                             FOR CORPORATE OFFICERS
                             ----------------------

                            LIST OF COVERED OFFICERS
                            ------------------------

                             AS OF SEPTEMBER 1, 2000

                   The list of Covered Officers is maintained
                      in the office of the Vice President,
                 Director of Human Resources and Labor Relations

                                     - A-1 -<PAGE>
                                                                   EXHIBIT 10.55

                                 AMENDMENT NO. 3
                                       TO
                            STOCK PURCHASE AGREEMENT

      AMENDMENT NO. 3 (this "AMENDMENT") dated as of December 28, 2001 to Stock
Purchase Agreement (the "STOCK PURCHASE AGREEMENT") dated as of August 23, 2001
between HEALTHSTAR HOLDINGS LLC, a New Jersey limited liability Corporation
("HOLDINGS") and BIONUTRICS, INC., a Nevada corporation ("BNRX" or the
"CORPORATION") as amended by Amendment No. 1 dated as of August 23, 2001 (the
"FIRST AMENDMENT") and Amendment No. 2 dated as of October 31, 2001 (the "SECOND
AMENDMENT") by and among Holdings, BNRX and the purchasers of shares of Common
Stock of the Corporation whose names appear on that certain accession agreement
who will agree to be bound by the Stock Purchase Agreement, as amended
(collectively, the "INVESTORS").

                                   BACKGROUND

      A. Section 10.9 of the Stock Purchase Agreement provides that Holdings and
BNRX may amend the Stock Purchase Agreement by an agreement in writing signed by
both parties.

      B. Further, the parties hereto have agreed to amend certain matters in
connection with the Closing of the Stock Purchase Agreement, which they desire
to formalize and reduce to writing as set forth in this Amendment.

      NOW THEREFORE, the parties hereto, intending to be legally bound, hereby
agree as follows:

      1. DEFINITIONS. Unless otherwise set forth herein, all capitalized terms
shall have the meaning ascribed to them in the Stock Purchase Agreement and the
First Amendment.

      2. MULTIPLE CLOSINGS. Section 1.3 of the Stock Purchase Agreement, as
amended by the First Amendment and Second Amendment, is hereby further amended
and restated to read in its entirety as follows:

                  "1.3 Closing. The initial closing of the transactions
            contemplated by the Stock Purchase Agreement, as amended, in an
            amount of at least the Holdings Shares and the Minimum Purchased
            Shares (the "INITIAL CLOSING") shall occur on or before January 31,
            2002 (the "INITIAL CLOSING DATE"). Thereafter, one or more
            subsequent closings of the transactions contemplated by the Stock
            Purchase Agreement, as amended, each of an amount of no less than
            one hundred thousand (100,000) Purchased Shares, shall occur on or
            before March 31, 2002 (each a "SUBSEQUENT CLOSINGS"); provided
            however that Holdings may extend the Initial Closing Date in
<PAGE>
            its sole discretion if any of the conditions to Holdings' obligation
            to close set forth in Article V of the Stock Purchase Agreement, as
            amended, are not satisfied in Holding's sole and absolute
            discretion. Closings shall occur at Holdings' offices located at 100
            Woodbridge Center Drive Suite 202, Woodbridge, New Jersey 07095 or
            such other location as Holdings may advise the Corporation in
            writing.

      3. SHAREHOLDER APPROVAL. Section 5.13 of the Stock Purchase Agreement is
hereby amended by deleting Section 5.13 in its entirety and replacing it with
the following:

                  "5.13 Shareholder Approval. BNRX shall have obtained the
            requisite shareholder approval by a solicitation, in form and
            substance acceptable to Holdings, for a charter amendment to allow
            the number of directors to be increased or decreased, from time to
            time, in such manner as provided in the bylaws of the Company.

      4. ALL OTHER TERMS. All other terms of the Agreement, the First Amendment
and Second Amendment shall remain in full force and effect.

      5. COUNTERPARTS. This Amendment may be executed in any number of
counterparts, each of which shall be deemed an original but all of which
together shall constitute one and the same instrument.

HEALTHSTAR HOLDING LLC                    BIONUTRICS, INC.

By: /s/ Peter Cossman                     By: /s/ Ronald H. Lane
    -----------------------                   -----------------
Name:  Peter Cossman                      Name:  Ronald Howard Lane, Ph.D.
Title:  Vice President                    Title:  Chairman and Chief
                                          Executive Officer

                                       2<PAGE>
                               AMENDMENT NO. 4
                                      TO
                           STOCK PURCHASE AGREEMENT

      AMENDMENT No. 4 (this "Amendment"), dated as of January 29, 2002, to Stock
Purchase Agreement (the "Stock Purchase Agreement"), dated as of August 23,
2001, between HEALTHSTAR HOLDINGS, LLC, a New Jersey limited liability company
("Holdings"), and BIONUTRICS, INC., a Nevada corporation ("BNRX" or the
"Corporation"), as amended by Amendment No. 1, dated as of August 23, 2001 (the
"First Amendment"), Amendment No. 2, dated as of October 31, 2001 (the "Second
Amendment"), and Amendment No. 3, dated as of December 28, 2001 (the "Third
Amendment"), by and among Holdings, BNRX and the purchasers of shares of Common
Stock of the Corporation whose names appear on that certain accession agreement
who will agree to be bound by the Stock Purchase Agreement, as amended
(collectively, the "Investors").

                                  BACKGROUND

      A. Section 10.9 of the Stock Purchase Agreement provides that Holdings and
BNRX may amend the Stock Purchase Agreement by an agreement in writing signed by
both parties.

      B. Further, the parties hereto have agreed to amend certain matters in
connection with the Closing of the Stock Purchase Agreement, which they desire
to formalize and reduce to writing as set forth in this Amendment.

      NOW THEREFORE, the parties hereto, intending to be legally bound, hereby
agree as follows:

      1. DEFINITIONS. Unless otherwise set forth herein, all capitalized terms
shall have the meaning ascribed to them in the Stock Purchase Agreement and the
First Amendment.

      2. MULTIPLE CLOSINGS. Section 1.3 of the Stock Purchase Agreement, as
amended by the First Amendment, Second Amendment and Third Amendment, is hereby
further amended and restated to read in its entirety as follows:

                  "1.3 Closing. The initial closing of the transactions
            contemplated by the Stock Purchase Agreement, as amended, in an
            amount of at least the Holdings Shares and the Minimum Purchased
            Shares (the "Initial Closing") shall occur on or before March 1,
            2002 (the "Initial Closing Date"). Thereafter, one or more
            subsequent closings of the transactions contemplated by the Stock
            Purchase Agreement, as amended, each of an amount of no less than
            one hundred thousand (100,000) Purchased Shares, shall occur on or
            before May 1, 2002 (each a "Subsequent Closings"); provided however
            that Holdings may extend the Initial Closing Date in its sole
            discretion if any of the conditions to Holdings obligation to close
            set forth in Article V of the Stock Purchase Agreement, as amended,
            are not satisfied in Holding's sole and
<PAGE>
            absolute discretion. Closings shall occur at Holdings' offices
            located at 100 Woodbridge Center Drive Suite 202, Woodbridge, New
            Jersey 07095 or such other location as Holdings may advise the
            Corporation in writing.

      3. ALL OTHER TERMS. all other terms of the Agreement, the First Amendment,
Second Amendment and Third Amendment shall remain in full force and effect.

      4. COUNTERPARTS. This Amendment may be executed in any number of
counterparts, each of which shall be deemed an original but all of which
together shall constitute one and the same instrument.

HEALTHSTAR HOLDINGS, LLC                  BIONUTRICS, INC.

By: /s/ Peter Cossman                     By: /s/ William McCormick
    --------------------------            --------------------------------
Name: Peter Cossman                       Name: William McCormick
Title: Vice President                     Title: Director

                                       2

Source: [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00035-of-00352.parquet"}, [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00035-of-00352.parquet"}], [{"source": "alea-institute/alea-institute/kl3m-data-edgar-agreements/train-00035-of-00352.parquet"}]]