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                                                                   Exhibit 10.28

                     AMENDMENTS TO 1993 STOCK OPTION PLAN
                                April 28, 1995

The shareholders of Summit Medical Systems, Inc. (the "Company") adopted the
following amendments to the Company's Stock Option Plan of 1993 (the "Plan") at
their annual meeting held on April 28, 1995:

1.   The first amendment adopted was to replace in its entirety Section 5.1 of
the Plan with the following text:

     5.1  Number.  The number of shares of Stock hereby made available and
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reserved for issuance under the Plan is 820,000. The aggregate number of shares
of Stock available under this Plan shall be subject to adjustment as provided in
Section 5.3. The total number of shares of Stock may be authorized but unissued
shares of Stock, or shares acquired by purchase as directed by the Board from
time to time in its discretion, to be used for issuance upon exercise of Options
granted hereunder.

2.   The second amendment adopted was to replace in its entirety Section 13.1 of
the Plan with the following text:

     13.1 Acquisition.  In the event that an Acquisition occurs with respect to
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the Company, the Company shall cancel Options outstanding as of the effective
date of Acquisition, whether or not such Options are then exercisable, in return
for payment to the Optionees of an amount equal to a reasonable estimate of an
amount (hereinafter the "Spread") equal to the difference between the net amount
per share payable in the Acquisition, or as a result of the Acquisition, less
the exercise price of the Option. In estimating the Spread, appropriate
adjustments to give effect to the existence of the Options shall be made, such
as deeming the Options to have been exercised, with the Company receiving the
exercise price payable thereunder, and treating the shares receivable upon
exercise of the Options as being outstanding in determining the net amount per
share. For purposes of this section, an "Acquisition" shall mean any transaction
in which substantially all of the Company's assets are acquired or in which a
controlling amount of the Company's outstanding shares are acquired, in each
case by a single person or entity or an affiliated group of persons and/or
entities. For purposes of this Section a controlling amount shall mean more than
fifty percent (50%) of the issued and outstanding shares of Stock of the
Company. The Company shall have such an obligation regardless of how the
Acquisition is effectuated, whether by direct purchase, through a merger or
similar corporate transaction, or otherwise. In cases where the acquisition
consists of the acquisition of assets of the Company, the net amount per share
shall be calculated on the basis of the net amount receivable with respect to
shares upon a distribution and liquidation by the Company after giving effect to
expenses and charges, including but not limited to taxes, payable by the Company
before the liquidation can be completed.

     If the Company has no obligations under this Section 13.1 the remaining
provisions of this Article XIII shall apply, to the extent applicable.

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                          SUMMIT MEDICAL SYSTEMS, INC.

                 SECOND AMENDMENT TO THE 1993 STOCK OPTION PLAN

                                 APRIL 25, 1996

     I, Dennis H. Powers, Secretary of Summit Medical Systems, Inc., a Minnesota
corporation (the "Company"), hereby certify on behalf of the Company that in
March of 1996, pursuant to Section 12.1 of the Company's Stock Option Plan
of 1993, as amended (the "Plan"), the Board of Directors approved a second
amendment to the Plan providing for the issuance of an additional 1,300,000
shares of common stock under the Plan (the "Second Amendment").  The
shareholders of the Company adopted the Second Amendment at their Annual Meeting
held on April 25, 1996.  Accordingly, Section 5.1 of the Plan is hereby amended
and restated as follows:

          5.1  Number.  The number of shares of Stock hereby made available and
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     reserved for issuance under the Plan is 2,126,666.  The aggregate number of
     shares of Stock available under this Plan shall be subject to adjustment as
     provided in Section 5.3.  The total number of shares of Stock may be
     authorized but unissued shares of Stock, or shares acquired by purchase as
     directed by the Board from time to time in its discretion, to be used for
     issuance upon exercise of Options granted hereunder.

     IN WITNESS WHEREOF, I have hereto signed my name.

                                        ________________________________________
                                        Dennis H. Powers
                                        Secretary

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