THESE WARRANTS AND THE UNDERLYING COMMON STOCK HAVE NOT BEEN REGISTERED UNDER
THE SECURITIES ACT OF 1933 OR THE SECURITIES LAWS OF ANY STATE. THESE WARRANTS
HAVE BEEN ACQUIRED FOR INVESTMENT AND NOT WITH A VIEW TO DISTRIBUTION OR RESALE,
AND THESE WARRANTS AND THE UNDERLYING COMMON STOCK MAY NOT BE SOLD, MORTGAGED,
PLEDGED, HYPOTHECATED OR OTHERWISE TRANSFERRED WITHOUT AN EFFECTIVE REGISTRATION
STATEMENT UNDER THE SECURITIES ACT OF 1933 AND APPLICABLE STATE SECURITIES LAWS,
OR AN OPINION OF COUNSEL SATISFACTORY TO THE COMPANY THAT REGISTRATION IS NOT
REQUIRED UNDER SUCH ACT OR LAWS.

                                MYO DIAGNOSTICS, INC.

                                   SERIES B WARRANT
                            83,333 Shares of Common Stock

No. B-1                                                 Dated: December 23, 1994

    THIS CERTIFIES THAT, FOR VALUE RECEIVED, ONTARIO MUNICIPAL EMPLOYEES
RETIREMENT BOARD, or registered assigns ("Holder") is entitled to purchase, upon
the terms and subject to the provisions of this Warrant, from MYO DIAGNOSTICS,
INC., a California corporation (the "Company") 83,333 fully paid and
nonassessable shares of the Common Stock of the Company at the price of $3.00
per share at any time during the period from the date hereof to 5:00 P.M., Los
Angeles time, on June 23, 1997 (the "Expiration Date"), at which time this
Warrant shall expire and become void.  The number of shares of Common Stock to
be received upon the exercise of this Warrant and the price to be paid for each
share of Common Stock shall be adjusted from time to time as hereinafter set
forth.  As used herein, "Common Stock" shall mean the Company's currently
authorized Common Stock and any stock into which such Common Stock may be
exchanged, and the exercise price for a share of Common Stock in effect at any
time and as adjusted from time to time is hereinafter sometimes referred to as
the "Exercise Price".  Unless the context otherwise requires, the term
"Warrant", as used herein, includes this Warrant and any other Warrant or
Warrants which may be issued pursuant to the provisions of this Warrant, whether
upon transfer, assignment, partial exercise, divisions, combinations, exchange
or otherwise, and the term "Holder" includes any transferee or transferees or
assignee or assignees of the Holder named above, all of whom shall be subject to
the provisions of this Warrant.

    1.  METHOD OF EXERCISE.  This Warrant may be exercised in whole or in part
at any time or from time to time after the date hereof but not after the
Expiration Date by presentation and surrender hereof to the Company at 3710
South Robertson Blvd., Suite 212, Culver City, California 90232 or at such other
office as may be designated by the Company, with the Purchase Form attached
hereto duly executed and accompanied by payment to the Company by cash or check
or bank draft payable to the order of the Company, of



an amount equal to the then applicable Exercise Price multiplied by the number
of shares of Common Stock specified in such Form.  If this Warrant should be
exercised in part only, the Company shall, upon presentation of this Warrant
upon such exercise, execute and deliver a new Warrant evidencing the right of
the Holder hereof to purchase the balance of the shares of Common Stock
purchasable hereunder upon the same terms and conditions as herein set forth.
The Company agrees that the shares so purchased shall be deemed to be issued to
the Holder hereof as the record owner of such shares as of the close of business
on the date on which this Warrant shall have been surrendered and payment made
for such shares as aforesaid.  Certificates for the shares of Common Stock so
purchased shall be dated the date of exercise and delivered to the Holder hereof
within a reasonable time, not exceeding 10 Trading Days (as hereinafter
defined), after the rights represented by this Warrant shall have been
exercised.

    2.   RESERVATION AND LISTING OF SHARES; ISSUE TAXES.  The Company hereby
agrees that at all times prior to the Expiration Date it will have authorized,
and reserved for the purpose of issue upon exercise of this Warrant, a
sufficient number of shares of its Common Stock to provide for the exercise of
this Warrant, in full and that, upon issuance, such shares will be listed on
each national securities exchange, if any, on which the other shares of the
outstanding Common Stock of the Company are then listed.  The Company hereby
agrees that all shares of Common Stock issuable upon exercise of this Warrant
will, upon issuance, be fully paid and nonassessable.  The Company hereby agrees
that it will pay all documentary, stamp or similar taxes and other governmental
charges which may be imposed with respect to the issuance or delivery of any
shares of Common Stock upon exercise of this Warrant; provided, however, that if
the shares of Common Stock are to be issued in a name other than the name of the
Holder of this Warrant, then no such issuance or delivery shall be made unless
the person requesting the same has paid to the Company any necessary transfer
tax or other governmental charge incident thereto.

    3.  FRACTIONAL SHARES.  If the number of shares of Common Stock purchasable
upon the exercise of this Warrant is adjusted pursuant to the provisions of
Section 6 hereof, the Company shall nevertheless not be required to issue any
fractional shares or scrip representing fractional shares upon the exercise of
this Warrant.  With respect to any fraction of a share called for upon any
exercise hereof, the Company shall pay to the Holder an amount in cash equal to
such fraction multiplied by the Current Market Price (determined as hereinafter
provided) of one share of Common Stock on the last Trading Day prior to the date
of exercise of this Warrant.  The Current Market Price of a share of Common
Stock for any day shall be determined as follows:

    (a) If the Common Stock is listed on one or more national securities
exchanges or admitted to unlisted trading privileges on



any such exchange, the Current Market Price shall be the last sale price of the
Common Stock reported by the principal exchange on which the Common Stock is
traded on such day; or

    (b) If the Common Stock is not so listed or admitted to unlisted trading
privileges, the Current Market Price shall be the mean of the last reported bid
and asked prices on such day, as reported by the National Association of
Securities Dealers Automated Quotation System, or if not so reported, as
furnished by the National Quotation Bureau, Inc., or, if such firm at the time
is not engaged in the business of reporting such prices, as furnished by any
similar firm then engaged in such business as selected by the Company, or if
there is no such firm, as furnished by any member of the National Association of
Securities Dealers, Inc. selected by the Company; or

    (c) If the Common Stock is not so listed or admitted to unlisted trading
privileges and bid and asked prices are not so reported, the Current Market
Price shall be an amount determined in good faith and in a reasonable manner by
the Board of Directors of the Company.

    "Trading Day" means any day on which trades in the Common Stock of the
Company are reported by a national securities exchange or if such Common Stock
is not listed or admitted to trading privileges on any such exchange, any day
such Common Stock is traded in the over-the-counter market, provided that if
Current Market Price is being determined pursuant to clause (c) of Section 3,
"Trading Day" shall mean any day on which the New York Stock Exchange is open
for trading.

    4.  TRANSFER AND EXCHANGE.  Subject to the provisions of Section 8 hereof,
this Warrant and all rights hereunder are transferable, in whole or in part, on
the books of the Company by the Holder hereof in person or by duly authorized
attorney, upon presentation and surrender of this Warrant at the principal
office of the Company with the Assignment Form attached hereto duly executed and
upon payment of any necessary transfer tax or other governmental charge imposed
upon such transfer.  Upon any partial transfer of this Warrant, the Company will
issue and deliver to the Holder an appropriate new Warrant or Warrants.  Each
taker and Holder of this Warrant, by taking or holding the same, consents and
agrees that this Warrant when endorsed in blank shall be deemed negotiable and
that when this Warrant shall have been so endorsed, the Holder hereof may be
treated by the Company and all other persons dealing with this Warrant as the
absolute owner hereof for any purpose and as the person entitled to exercise the
rights represented hereby, or to the transfer hereof on the books of the
Company, any notice to the contrary notwithstanding; but until such transfer on
such books, the Company may treat the registered Holder hereof as the owner for
all purposes.  This Warrant is exchangeable at the principal office of the
Company for Warrants for the



purchase of the same aggregate number of shares of Common Stock, each new
Warrant to represent the right to purchase such number of shares of Common Stock
as the Holder hereof shall designate at the time of such exchange.  All Warrants
issued on transfers or exchanges shall be dated the date hereof and shall be
identical to this Warrant except as to the number of shares of Common Stock
issuable pursuant thereto.

    5.  LOSS OR MUTILATION.  Upon receipt by the Company of evidence
satisfactory to it of the ownership of and loss, theft, destruction or
mutilation of this Warrant and, in the case of loss, theft or destruction, of
indemnity satisfactory to the Company and, in the case of mutilation, upon
surrender and cancellation thereof, the Company shall (in the absence of notice
to the Company that this Warrant has been acquired by a bona fide purchaser)
execute and deliver to the Holder hereof in lieu hereof, a new Warrant of like
tenor and date and any such lost, stolen or destroyed Warrant shall thereupon
become void.

    6.  ADJUSTMENT OF PURCHASE PRICE AND NUMBER OF SHARES.  The number and kind
of securities purchasable upon the exercise of this Warrant and the Exercise
Price shall be subject to adjustment from time to time upon the happening of
certain events, as follows:

    (a) RECLASSIFICATION, CONSOLIDATION OR MERGER.  In case of any
reclassification or change of outstanding securities of the class issuable upon
exercise of this Warrant (other than a change in par value, or from par value to
no par value, or from no par value to par value or as a result of a subdivision
or combination), or in case of any consolidation or merger of the Company with
or into another corporation (other than a merger with another corporation in
which the Company is the continuing corporation and which does not result in any
reclassification or change of outstanding securities issuable upon exercise of
this Warrant), the Company, or such successor, as the case may be, shall,
without payment of additional consideration therefor, execute a new Warrant,
providing that the Holder of this Warrant shall have the right to exercise such
new Warrant and procure upon such exercise, in lieu of each share of Common
Stock theretofore issuable upon exercise of this Warrant, the kind and amount of
shares of stock, other securities, money and property receivable upon such
reclassification, change, consolidation, or merger, by a holder of one share of
Common Stock issuable upon exercise of this Warrant, had this Warrant been
exercised immediately prior to the record date for determining the holders of
Common Stock to receive such shares of stock, other securities, money and
property in connection with any such reclassification, change, consolidation, or
merger.  Such new Warrant shall provide for adjustments which shall be as nearly
equivalent as may be practicable to the adjustments provided for in this Section
6.

The provisions of this Section 6(a) shall similarly apply to



successive reclassifications, changes, consolidations and mergers.

    (b) SUBDIVISION OR COMBINATION OF SHARES.  If the Company, at any time
while this Warrant remains outstanding and unexpired, shall subdivide or combine
its Common Stock, the Exercise Price shall be proportionately decreased in the
case of a subdivision or increased in the case of a combination at the effective
time of such subdivision or combination, or if the Company shall set a record
date for the purpose of determining the Common Stock initially affected by such
subdivision or combination, if earlier, as of such record date.

    (c) STOCK DIVIDENDS.  If the Company at any time while this Warrant is
outstanding and unexpired shall pay a dividend or make any other distribution
(except any distribution specifically provided for in Section 6(a) or 6(b)
hereof) on the Common Stock in shares of Common Stock, then the Exercise Price
shall be adjusted, from and after the date of determination of stockholders
entitled to receive such dividend or distribution, to that price determined by
multiplying the Exercise Price in effect immediately prior to such date of
determination by a fraction (i) the numerator of which shall be the total number
of shares of Common Stock outstanding immediately prior to such dividend or
distribution, and (ii) the denominator of which shall be the total number of
shares of Common Stock outstanding immediately after such dividend or
distribution (plus, in the event the Company pays cash for fractional shares,
the number of additional shares which would have been outstanding had the
Company issued fractional shares in connection with such dividend).

    (d) RIGHTS OFFERINGS.  If the Company shall issue rights, options, or
warrants to all holders of its outstanding shares of Common Stock, entitling
them (for a period expiring within 45 days after the record date for the
determination of shareholders entitled to receive such rights, options or
warrants) to subscribe for or purchase shares of Common Stock (or securities
exchangeable for or convertible into shares of Common Stock) at a price per
share of Common Stock (or having an exchange or conversion price per share of
Common Stock, with respect to a security exchangeable for or convertible into
shares of Common Stock) that is less than the Exercise Price in effect,
immediately prior to such record date, then such Exercise Price shall be
adjusted by multiplying such Exercise Price by a fraction, the numerator of
which shall be the number of shares of Common Stock outstanding on such record
date plus the number of shares of Common Stock that the aggregate offering price
of the total number of shares of Common Stock so to be offered (or,the aggregate
initial exchange or conversion price of the exchangeable or convertible
securities so to be offered) would purchase at such Exercise Price and the
denominator of which shall be the number of shares of Common Stock outstanding
on such record date plus the number of additional shares of Common Stock to be
offered for subscription or purchase (or into which the



exchangeable or convertible securities so to be offered are initially
exchangeable or convertible).  Such adjustment shall become effective at the
close of business on such record date; however, to the extent that shares of
Common Stock (or securities exchangeable for or convertible into shares of
Common Stock) are not delivered after the expiration of such rights, options, or
warrants, the Exercise Price shall be readjusted (but only to the extent this
Warrant is unexercised after such expiration) to the Exercise Price that would
then be in effect had the adjustment made upon the issuance of such rights,
options, or warrants been made upon the basis of delivery of only the number of
shares of Common Stock (or securities exchangeable for or convertible into
shares of Common Stock) actually issued.  In case any subscription price may be
paid in a consideration, part or all of which shall be in a form other than
cash, the value of such consideration shall be as determined by the Board of
Directors in good faith and in a reasonable manner.

    (e) DISTRIBUTIONS OF ASSETS AND INDEBTEDNESS.  If the Company shall
distribute to all holders of its shares of Common Stock (including any such
distribution made in connection with a consolidation or merger in which the
Company is the surviving corporation) evidences of its indebtedness or assets,
then in each case the Exercise Price shall be adjusted by multiplying the
Exercise Price in effect immediately prior to the record date for the
determination of shareholders entitled to receive such distribution by a
fraction, the numerator of which shall be such Exercise Price, less the fair
market value (as determined by the Board of Directors of the Company acting in
good faith and in a reasonable manner) of the portion of the evidences of
indebtedness or assets so to be distributed applicable to one share of Common
Stock and the denominator of which shall be such Exercise Price.  Such
adjustment shall be made whenever any such distribution is made, and shall
become effective on the date of distribution retroactive to the record date for
the determination of shareholders entitled to receive such distribution.  This
Section 6(e) does not apply to (i) cash dividends payable out of consolidated
retained earnings, (ii) dividends or distributions payable in shares of stock
referred to in Section 6(c) above or (iii) rights, options or warrants referred
to in Section 6(d) above.

    (f) COMMON STOCK ISSUE, OPTIONS, WARRANTS, CONVERTIBLE SECURITIES, ETC.  If
the Company shall sell or issue shares of Common Stock, or rights, options,
warrants or convertible or exchangeable securities containing the right to
subscribe for or purchase shares of Common Stock for a consideration per share
of Common Stock (determined, in the case of such rights, options, warrants or
convertible or exchangeable securities, by dividing (i) the total amount
received or receivable by the Company in consideration of the sale and issuance
of such rights, options, warrants or convertible or exchangeable securities,
plus the total



consideration payable to the Company upon exercise or conversion or exchange
thereof, by (ii) the total number of shares of Common Stock covered by such
rights, options, warrants or convertible or exchangeable securities) lower than
the Exercise Price in effect on the date the Company fixes the offering price
(or exercise price, option price or conversion price, as the case may be) per
share of such Common Stock, then the Exercise Price shall be reduced to a price
determined by multiplying the Exercise Price in effect immediately prior thereto
by a fraction, the numerator of which shall be an amount equal to the sum of (A)
the number of shares of Common Stock outstanding immediately prior to such sale
and issuance plus (B) the number of shares of Common Stock which the aggregate
consideration received (determined as provided below) for such sale or issuance
would purchase at such Exercise Price, and the denominator of which shall be the
total number of shares of Common Stock to be outstanding immediately after such
sale and issuance.  Such adjustment shall be made successively whenever such an
issuance is made.  For the purposes of such adjustments, the shares of Common
Stock which the holder of any such rights, options, warrants, or convertible or
exchangeable securities shall be entitled to subscribe for or purchase shall be
deemed to be issued and outstanding as of the date of such sale and issuance and
the consideration received by the Company therefor shall be deemed to be the
consideration received by the Company for such rights, options, warrants or
convertible or exchangeable securities, plus the consideration or premiums
stated in such rights, options, warrants or convertible or exchangeable
securities to be paid for the shares of Common Stock covered thereby.  For the
purposes of determining "consideration per share of Common Stock" or
"consideration received by the Company" for the purposes of the first sentence
of this Section 6(f), no deduction shall be made for commissions, discounts or
other expenses incurred by the Company for any underwriting of the issue or
otherwise in connection therewith.  In case the Company shall sell and issue
shares of Common Stock, or rights, options, warrants or convertible or
exchangeable securities containing the right to subscribe for or purchase shares
of Common Stock, for a consideration consisting, in whole or in part, of
property other than cash or its equivalent, then in determining the
"consideration per share of Common Stock" and the "consideration received by the
Company" for purposes of the first sentence of this Section 6(f), the Board of
Directors shall determine the fair value of such property, acting in good faith
and in a reasonable manner.  This Section 6(f) does not apply to (i) shares,
rights, options, warrants or convertible or exchangeable securities issued in
any of the transactions described in Sections 6(a) through 6(e), (ii) Common
Stock issued upon the exercise of rights, options, or warrants (including this
Warrant) or upon the conversion or exchange of convertible or exchangeable
securities, (iii) options to purchase not in excess of 400,000 shares of Common
Stock issued or to be issued pursuant to that certain Agreement, dated December
13, 1994, between the Company and Donald Patterson, Ronald Goldsack, James
Connacher, Chris Skillen, Richard Reid and 



James Black, or (iv) options to purchase not in excess of 400,000 shares of
Common Stock issued after the date hereof to employees, consultants, officers or
directors of the Company (other than Gerald D. Appel).

    (g) OTHER ADJUSTMENTS.  If any event occurs as to which in the opinion of
the Board of Directors of the Company, the other provisions of this Section 6
are not strictly applicable or if strictly applicable would not fairly protect
the purchase rights of the Holder in accordance with the essential intent and
principles of such provisions, then the Board of Directors shall make an
adjustment in the application of such provisions, in accordance with such
essential intent and principles, so as to protect such purchase rights as
aforesaid, but in no event shall any such adjustment have the effect of
increasing the Exercise Price as otherwise determined pursuant to this Section
6.

    (h) ADJUSTMENT OF NUMBER OF SHARES.  Upon each adjustment of the Exercise
Price, the number of shares of Common Stock purchasable hereunder shall be
adjusted to the product obtained by multiplying such number of shares
purchasable immediately prior to such adjustment in the Exercise Price by a
fraction, the numerator of which shalt be the Exercise Price in effect
immediately prior to such adjustment and the denominator of which shall be the
Exercise Price in effect immediately thereafter.

    (i) MINIMUM ADJUSTMENT.  No adjustment in the Exercise Price shall be
required unless such adjustment would require an increase or decrease of at
least $.05 in the Exercise Price; provided, however, that any adjustments which
by reason of this Section 6(i) are not required to be made shall be carried
forward and taken into account in any subsequent adjustment.  All calculations
under this Section 6 shall be made to the nearest one-tenth of one cent or to
the nearest one-tenth of a share, as the case may be.

    (j) SECURITIES OTHER THAN COMMON STOCK.  In the event that at any time, as
a result of an adjustment made pursuant to this Section 6, the Holders of this
Warrant shall become entitled to purchase any shares or securities of the
Company other than shares of Common Stock, thereafter the number of such other
shares or securities so purchasable upon exercise of this Warrant and the
Exercise Price for such shares or securities shall be subject to adjustment from
time to time in a manner and on terms as nearly equivalent as practicable to the
provisions with respect to the shares of Common Stock contained in Section 6(a)
through 6(h), inclusive, of this Section 6 and the other provisions hereof with
respect to the shares of Common Stock shall apply on like terms to any such
other shares.

    (k) DEFERMENT OF ADJUSTMENT.  In any case in which this Section 6 shall
require that an adjustment in the Exercise Price be made effective as of a
record date for a specified event, the



Company may elect to defer until the occurrence of such event issuing to the
Holder of any Warrant exercised after such record date the shares of Common
Stock, if any, issuable upon such exercise over and above the shares of Common
Stock, if any, issuable upon such exercise on the basis of the Exercise Price in
effect prior to such adjustment.

    (l) VOLUNTARY ADJUSTMENT BY THE COMPANY.  The Company may at its option, at
any time during the term of this Warrant, reduce the then current Exercise Price
for any period of time to any amount deemed appropriate by the Board of
Directors of the Company.

    7.  NOTICE OF ADJUSTMENTS.  Whenever any Exercise Price shall be adjusted
pursuant to Section 6 hereof, the Company shall promptly prepare a certificate
of its chief financial officer setting forth, in reasonable detail the event
requiring the adjustment, the amount of the adjustment, the method by which such
adjustment was calculated, and the Exercise Price after giving effect to such
adjustment, and shall promptly cause copies of such certificate to be made (by
first class mail, postage prepaid) to the Holder of this Warrant.

    8.  RESTRICTIONS ON TRANSFER; LEGENDS.  This Warrant was issued pursuant to
that certain Securities Purchase Agreement dated as of December 23, 1994, among
the Company, Ontario Municipal Employees Retirement Board, Gerald D. Appel and
Hershel Toomim (the "Purchase Agreement"), a copy of which will be furnished,
without charge, to the Holder hereof upon written request to the Company.  Each
taker and Holder of this Warrant, by taking and holding the same, represents,
acknowledges and agrees that (a) this Warrant was, and any shares of Common
Stock acquired upon exercise hereof will be (unless then registered under the
Securities Act of 1933 or an exemption from such registration not requiring such
representation is available for the sale of the Common Stock), acquired for
investment and not with a view to or for sale in connection with any
distribution thereof, (b) this Warrant has not been, and the shares of Common
Stock issuable upon exercise hereof may not be, registered under the Securities
Act of 1933 (the "1933 Act"), may not be transferred in violation of the 1933
Act, and must be held indefinitely unless they are subsequently registered
thereunder or an exemption from such registration is available, and (c) this
Warrant and the shares of Common Stock issuable upon exercise hereof are subject
to other restrictions on transfer by the provisions of the Purchase Agreement,
including, without limitation, Sections 8.01 and 8.12 thereof.  Each taker and
Holder of this Warrant, by taking and holding the same, also agrees that all
certificates representing Common Stock issued upon exercise of this Warrant may
bear the restrictive legend set forth in Section 4.06 of the Purchase Agreement
and may bear such other legends and endorsements as shall be required to comply
with any law or with any rule or regulation of any stock exchange on which such
securities may be listed.



    9.  EXTENSION OF EXPIRATION DATE.  In addition, and notwithstanding any
provision contained herein to the contrary, in the event that (a) at the
Expiration Date the Company is required, pursuant to an effective request
therefor received by the Company from the Holder pursuant to the provisions of
Section 8.03 of the Purchase Agreement at least 90 days prior to the Expiration
Date, to effect a Registration under the Securities Act of 1933 with respect to
any shares of Common Stock subject to this Warrant or (b) at the Expiration Date
the Company is in the process of effecting a registration under the Securities
Act of 1933 for an underwritten public offering in which shares of Common Stock
subject to this Warrant are entitled to be included pursuant an effective
request therefor received by the Company from the Holder pursuant to the
provisions of Section 8.02 of the Purchase Agreement on or prior to the
Expiration Date, the Expiration Date shall be extended to 5:00 P.M., Los Angeles
time, on the 30th day following the date on which such Registration shall have
become effective but in no event longer than 180 days after the date this
Warrant would otherwise have expired.  In the event that the Expiration Date is
extended in accordance with the provisions of this Section 9, all references
contained in this Warrant to the "Expiration Date" shall be deemed to be
references to the Expiration Date as so extended.

    10.  NO STOCKHOLDER RIGHTS. Nothing contained in this Warrant shall be
construed as conferring upon the Holders or their transferees the right to vote
or to receive dividends or to consent to or receive notice as shareholders in
respect of any meeting of shareholders for the election of directors of the
Company or any other matter, or any rights whatsoever as shareholders of the
Company.  If, however, at any time prior to the expiration of this Warrant and
prior to its exercise in full, any of the following events shall occur:

    (a) the Company shall declare any dividend payable in any securities upon
its shares of Common Stock or make any distribution to the holders of its shares
of Common Stock (other than a cash dividend or a dividend payable in additional
shares of Common Stock);

    (b) the Company shall offer to the holders of its shares of Common Stock
any additional shares of Common Stock or securities convertible into shares of
Common Stock or any right to subscribe to shares of Common Stock or securities
convertible or exchangeable into shares of Common Stock;

    (c) any reclassification of the capital stock of the Company (other than a
subdivision or combination of Common Stock), or any consolidation or merger to
which the Company is a party or any sale of all or substantially all of the
assets of the Company shall be proposed, and in each case shareholder approval
is required; or



    (d)  a dissolution, liquidation or winding up of the Company shall be
proposed;

then in any one or more of such events, the Company shall give notice in writing
of such event to the Holders of this Warrant at least 20 days prior to the date
fixed as a record date or the date of closing the transfer books for the
determination of the shareholders entitled to such dividend, distribution, or
subscription rights, or for the determination of shareholders entitled to vote
on any such proposed transactions.  Such notice shall specify such record date
or date of the closing of the transfer books, as the case may be.



    11. GOVERNING LAW.  This Warrant shall be governed by and construed in
accordance with the laws of the State of California.


                                            MYO DIAGNOSTICS, INC.



                                            By:   /s/ Gerald D. Appel
                                               ------------------------------
                                                 Name:  GERALD APPEL
                                                 Title: President



                                    PURCHASE FORM

                                                          Dated:         , 199
                                                               ---------     --
The undersigned hereby irrevocably elects to exercise the within Warrant to the
extent of purchasing ________ shares of Common Stock and hereby makes payment of
$_____________     in payment of the actual exercise price thereof.

                        INSTRUCTIONS FOR REGISTRATION OF STOCK

         Name
              -----------------------------------------------
              (Please typewrite or print in block letters)

         Address
                  ------------------------------------------

                  ------------------------------------------


                        Signature:
                                   ------------------------------

                                   ASSIGNMENT FORM

    FOR VALUE RECEIVED, ________________________________ hereby sells, assigns
and transfers unto

Name
    -------------------------------------------
    (Please typewrite or print in block letters)

Address ________________________________________________ the right to purchase
Common Stock represented by this Warrant to the extent of ______ shares as to
which such right is exercisable and does hereby irrevocably constitute and
appoint ____________________________, attorney, to transfer the same on the
books of the Company with full power of substitution in the premises.


                        Signature:
                                   ------------------------------

Dated:               , 199
      --------------     --



                            AMENDMENT TO SERIES B WARRANT

    This AMENDMENT TO SERIES B WARRANT (this "Amendment"), is made as of August
18, 1995, by and between Myo Diagnostics, Inc., a California corporation (the
"Company") and Ontario Municipal Employees Retirement Board ("OMERB")

                                       RECITALS

    A.   WHEREAS, OMERB is the holder of that certain Series B Warrant, No.
B-l, dated December 23, 1994, for 83,333 shares of the Common Stock of the
Company (the "Warrant"); and

    B.   WHEREAS, the Company, OMERB, Gerald D. and Appel are parties to that
certain Securities Purchase Agreement, dated as of August 18, 1995, providing,
INTER ALIA, for the purchase by OMERB from the Company of 111,111 shares (the
"Closing Shares") of the Common Stock of the Company; and

    C.   WHEREAS, the execution and delivery of this Amendment is a condition
precedent to the obligation of OMERB to purchaser the Closing Shares pursuant to
the Purchase Agreement

    NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the parties
hereto hereby agree as follows:

    1.  The first sentence of the introductory paragraph of the Warrant is
hereby amended to read in its entirety as follows:

         THIS CERTIFIES THAT, FOR VALUE RECEIVED, ONTARIO MUNICIPAL EMPLOYEES
         RETIREMENT BOARD, or registered assigns ("Holder") is entitled to
         purchase, upon the terms and subject to the provisions of this
         Warrant, from MYO DIAGNOSTICS, INC., a California corporation (the
         "Company") 83,333 fully paid and nonassessable shares of the Common
         Stock of the Company at the price of $2.25 per share at any time
         during the period from the date hereof to 5:00 P.M., Los Angeles time,
         on June 23, 1997 (the "Expiration Date"), at which time this Warrant
         shall expire and become void.

    2.  The Company hereby represents and warrants to OMERB that this Amendment
has been duly executed and delivered by the Company and that the Warrant, as
amended by this Amendment constitutes the legal, valid, and binding obligation
of the Company, enforceable against the Company in accordance with its terms.

    3.  OMERB hereby represents and warrants to the Company that this Amendment
has been duly executed and delivered by OMERB.

    4.  This Amendment may be executed in two or more counterparts



and by different parties in separate counterparts, each of which shall be deemed
an original, but all of which together shall constitute one and the same
instrument

    IN WITNESS WHEREOF, the parties have caused this Amendment to be executed
as of the date first above written.

                                            MYO DIAGNOSTICS, INC.


                                            By  /s/ Gerald D. Appel
                                              --------------------------------
                                              Gerald D. Appel
                                              President

                                            ONTARIO MUNICIPAL EMPLOYEES
                                            RETIREMENT BOARD


                                            By  /s/ Peter F. Friend
                                              --------------------------------
                                               Peter D. Friend
                                               Portfolio Manager


                                            By  /s/ Henry A. Rachfalowski
                                              --------------------------------
                                               Henry A. Rachfalowski
                                               Vice President



                         SECOND AMENDMENT TO SERIES B WARRANT

    This SECOND AMENDMENT TO SERIES B WARRANT (this "Amendment"), is made as of
December 22, 1995, by and between Myo Diagnostics, Inc,, a California
corporation (the "Company") and Ontario Municipal Employees Retirement Board
("OMERB")

                                       RECITALS

    A. WHEREAS, OMERB is the holder of that certain Series B Warrant, No. B-l,
dated December 23, 1994, for 83,333 shares of the Common Stock of the Company,
as amended by that certain Amendment to Series B Warrant dated as of August 18,
1995 (as so amended, the "Warrant"); and

    B.  WHEREAS, the Company and OMERB desire to further amend the Warrant as
hereinafter provided

    NOW, THEREFORE, in consideration of the premises and for other good and
valuable consideration, the receipt of which is hereby acknowledged, the parties
hereto hereby agree as follows:

    1.  The first sentence of the introductory paragraph of the Warrant is
hereby amended to read in its entirety as follows:

    THIS CERTIFIES THAT, FOR VALUE RECEIVED, ONTARIO MUNICIPAL EMPLOYEES
    RETIREMENT BOARD, or registered assigns ("Holder") is entitled to purchase,
    upon the terms and subject to the provisions of this Warrant, from MYO
    DIAGNOSTICS, INC., a California corporation (the "Company") 83,333 fully
    paid and nonassessable shares of the Common Stock of the Company at the
    price of $1.75 per share at any time during the period from the date hereof
    to 5:00 P.M., Los Angeles time, on June 23, 1998 (the "Expiration Date"),
    at which time this Warrant shall expire and become void.

    2.  The Company hereby represents and warrants to OMERB that this Amendment
has been duly executed and delivered by the Company and that the Warrant, as
amended by this Amendment constitutes the legal, valid, and binding obligation
of the Company, enforceable against the Company in accordance with its terms.

    3.  OMERB hereby represents and warrants to the Company that this Amendment
has been duly executed and delivered by OMERB.

    4.  This Amendment may be executed in two or more counterparts and by
different parties in separate counterparts, each of which shall be deemed an
original, but all of which together shall constitute one and the same instrument



    IN WITNESS WHEREOF, the parties have caused this Amendment to be executed
as of the date first above written.

                                            MYO DIAGNOSTICS, INC.


                                            By  /s/ Gerald D. Appel
                                              --------------------------------
                                              Gerald D. Appel
                                              President

                                            ONTARIO MUNICIPAL EMPLOYEES
                                            RETIREMENT BOARD


                                            By  /s/ Peter F. Friend
                                              --------------------------------
                                               Peter D. Friend
                                               Portfolio Manager


                                            By  /s/ Henry A. Rachfalowski
                                              --------------------------------
                                               Henry A. Rachfalowski
                                               Vice President