Document:

AGREEMENT OF LIMITED PARTNERSHIP

                                       OF

                           MOBILE KIDNEY STONE CENTERS
                             OF CALIFORNIA II, L.P.

<PAGE>

                                    AGREEMENT

                             OF LIMITED PARTNERSHIP

                                       OF

               MOBILE KIDNEY STONE CENTERS OF CALIFORNIA II, L.P.
               --------------------------------------------------

                                TABLE OF CONTENTS

                                                                    Page

         1.       FORMATION...........................................1
                  ---------

         2.       NAME................................................1
                  ----

         3.       OFFICES.............................................1
                  -------

         4.       PURPOSE.............................................2
                  -------

         5.       TERM................................................2
                  ----

         6.       CERTAIN DEFINED TERMS...............................2
                  ---------------------

         7.       CAPITAL CONTRIBUTIONS AND DILUTION OFFERINGS........6
                  --------------------------------------------

         8.       GUARANTIES..........................................7
                  ----------

         9.       CONDITIONS TO THE CAPITAL CONTRIBUTIONS OF CERTAIN LIMITED
                  ----------------------------------------------------------
                  PARTNERS.............................................7
                  --------

         10.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE GENERAL
                  --------------------------------------------------------
                  PARTNER..............................................7
                  -------

         11.      ADMISSION OF LIMITED PARTNERS........................8
                  -----------------------------

         12.      CAPITAL ACCOUNTS.....................................9
                  ----------------

         13.      ALLOCATIONS.........................................10
                  -----------

         14.      DISTRIBUTIONS.......................................11
                  -------------

         l5.      RIGHTS AND OBLIGATIONS OF LIMITED PARTNERS..........12
                  ------------------------------------------

         16.      LIMITED LIABILITY...................................14
                  -----------------

         17.      TRANSFER OF INTERESTS AND ADMISSION OF PARTNERS.....14
                  -----------------------------------------------

                                                         i

<PAGE>

         18.      OPTIONAL PURCHASE OF LIMITED PARTNERSHIP INTERESTS ON CERTAIN
                  -------------------------------------------------------------
                  EVENTS................................................18
                  ------

         19.      SALE, ASSIGNMENT OR OTHER TRANSFER OF THE GENERAL PARTNER'S
                  -----------------------------------------------------------
                  INTEREST..............................................24
                  --------

         20.      TERMINATION OF THE SERVICES OF THE GENERAL PARTNER....25
                  --------------------------------------------------

         21.      MANAGEMENT AND OPERATION OF BUSINESS..................25
                  ------------------------------------

         22.      RESERVES..............................................28
                  --------

         23.      INDEMNIFICATION AND EXCULPATION
                         OF THE GENERAL PARTNER.........................28

         24.      DISSOLUTION OF THE PARTNERSHIP........................29
                  ------------------------------

         25.      DISTRIBUTION UPON DISSOLUTION.........................30
                  -----------------------------

         26.      BOOKS OF ACCOUNT, RECORDS AND REPORTS.................31
                  -------------------------------------

         27.      NOTICES...............................................32
                  -------

         28.      AMENDMENTS............................................32
                  ----------

         29.      LIMITATIONS ON AMENDMENTS.............................32
                  -------------------------

         30.      MEETINGS, CONSENTS AND VOTING.........................33
                  -----------------------------

         31.      SUBMISSIONS TO THE LIMITED PARTNERS...................33
                  -----------------------------------

         32.      ADDITIONAL DOCUMENTS..................................33
                  --------------------

         33.      SURVIVAL OF RIGHTS....................................34
                  ------------------

         34.      INTERPRETATION AND GOVERNING LAW......................34
                  --------------------------------

         35.      SEVERABILITY..........................................34
                  ------------

         36.      AGREEMENT IN COUNTERPARTS.............................34
                  -------------------------

         37.      THIRD PARTIES.........................................34
                  -------------

         38.      POWER OF ATTORNEY.....................................34
                  -----------------

                                                        ii

<PAGE>

         39.      ARBITRATION...........................................35
                  -----------

         40.      CREDITORS.............................................35
                  ---------

                                    SCHEDULES

Schedule A  -  Schedule of Partnership Interests

                                       iii

<PAGE>

THE  LIMITED  PARTNERSHIP  INTERESTS  REPRESENTED  BY THIS  LIMITED  PARTNERSHIP
AGREEMENT HAVE NOT BEEN REGISTERED  WITH THE SECURITIES AND EXCHANGE  COMMISSION
UNDER THE  SECURITIES ACT OF 1933, AS AMENDED,  UNDER THE  CALIFORNIA  CORPORATE
SECURITIES LAW OF 1968, AS AMENDED,  OR REGISTERED UNDER SIMILAR LAWS OR ACTS OF
OTHER  STATES IN RELIANCE  UPON  EXEMPTIONS  UNDER SUCH LAWS.  IN  ADDITION,  NO
TRANSFERS OF LIMITED  PARTNERSHIP  INTERESTS MAY BE MADE WITHOUT COMPLIANCE WITH
THE RESTRICTIONS SET FORTH IN ARTICLE 17 BELOW.

                                    AGREEMENT

                             OF LIMITED PARTNERSHIP

                                       OF

                           MOBILE KIDNEY STONE CENTERS
                             OF CALIFORNIA II, L.P.

                  THIS AGREEMENT OF LIMITED  PARTNERSHIP  (the  "Agreement")  is
made  as of  April  1,  1999,  by and  among  MOBILE  KIDNEY  STONE  CENTERS  OF
CALIFORNIA,  LTD., a California limited partnership (the "General Partner"), and
persons listed on Schedule A attached hereto as the Limited Partners.

                  1.       FORMATION.
                           ---------

                  The  Partnership  was  formed  pursuant  to the  filing in the
Office of the Secretary of State of California on or about  December 11, 1998 of
a Certificate of Limited  Partnership  in accordance  with the provisions of the
Act.

                  2.       NAME.
                           ----

     2.1 The  name  of the  Partnership  is  "Mobile  Kidney  Stone  Centers  of
California II, L.P."

                  2.2 The  Partnership  business  shall be conducted  under such
names as the General  Partner may from time to time deem necessary or advisable,
provided that appropriate amendments to this Agreement and all necessary filings
under  applicable  assumed  or  fictitious  name  statutes  or the Act are first
obtained.

                  3.       OFFICES.
                           -------

                  3.1 The principal office of the Partnership  shall be at 15195
National Avenue, Suite 203, Los Gatos,  California 95032, or at such other place
as the  General  Partner  may be  required  to  maintain  within  the  State  of
California pursuant to the Act or may otherwise, from time to time, designate by
notice to the Limited Partners (the "Records Office").

                                       -1-

<PAGE>

                  3.2 The Partnership  may have such  additional  offices as the
General Partner may, from time to time, deem necessary or advisable.

                  4.       PURPOSE.
                           -------

                  The purpose and business of the  Partnership  shall be: (i) to
acquire and operate one or more transportable  lithotripters (or any other renal
stone treatment  equipment) for the treatment of renal stones primarily within a
150 mile radius of  Sacramento,  California or in such other  location(s) as the
General  Partner  may  determine,  in its  sole  discretion,  to be in the  best
interests  of the  Partnership;  (ii) to acquire  and  operate in the future any
other urological  device or equipment;  provided,  that such equipment as of the
date of  acquisition  by the  Partnership  has received FDA premarket  approval;
(iii)  to  acquire  an  interest  in any  business  entity,  including,  without
limitation,  a limited  partnership,  limited  liability company or corporation,
that engages in any business  activity  described in this Article 4; and (iv) to
engage in any and all activities  incidental or related to the  foregoing,  upon
and subject to the terms and conditions of this Agreement.

                  5.       TERM.
                           ----

                  The Partnership  shall terminate on December 31, 2049,  unless
sooner terminated as herein provided.

                  6.       CERTAIN DEFINED TERMS.
                           ---------------------

                  Certain terms used in this Agreement  shall have the following
meanings:

     Act. The Act means the California Revised Limited  Partnership Act, as then
in effect.

                  Affiliate.  An  Affiliate  is  (i)  any  person,  partnership,
corporation, association or other legal entity ("person") directly or indirectly
controlling, controlled by or under common control with another person; (ii) any
person owning or controlling 10% or more of the  outstanding  voting interest of
such other person;  (iii) any officer,  director or partner of such person;  and
(iv) if such other  person is an officer,  director  or partner,  any entity for
which such person acts in such capacity.

     Agreement.  This  Agreement  of  Limited  Partnership,  as the  same may be
amended from time to time.

     Bank. First-Citizens Bank & Trust Company, its successors and assigns.

     Capital Account.  The Partnership  capital account of a Partner as computed
pursuant to Article 12 of this Agreement.

                                                        -2-

<PAGE>

                  Capital  Contributions.  All capital  contributions  made by a
Partner or his or her  predecessor  in  interest  which shall  include,  without
limitation, contributions made pursuant to Article 7 of this Agreement.

     Capital  Transaction.  Any transaction which, were it to generate proceeds,
would produce Partnership Sales Proceeds or Partnership Refinancing Proceeds.

     Code.  The Internal  Revenue  Code of 1986,  as amended,  or  corresponding
provisions of subsequent, superseding revenue laws.

                  Dilution  Offering.   As  provided  in  Article  7.4  of  this
Agreement,  the future offering of additional limited  partnership  interests in
the  Partnership  as  determined  by the General  Partner.  Except as  otherwise
provided in Article 7.4, any successful  Dilution Offering will  proportionately
reduce the Percentage Interests of the then current Partners in the Partnership.

     Domestic Proceeding. Any divorce, annulment, separation or similar domestic
proceeding between a married couple.

                  Equipment.   The  equipment  used  in  the  operation  of  the
Lithotripter  System,  including the mobile transport vehicle, the transportable
lithotripter and miscellaneous  medical equipment and supplies,  and any similar
additional equipment acquired by the Partnership in the future.

                  FDA.  The United States Food and Drug Administration.

     General  Partner.  The general  partner of the  Partnership,  Mobile Kidney
Stone Centers of California, Ltd., a California limited partnership.

                  Guaranty.  The  Guaranty  Agreement  pursuant  to  which  each
Limited Partner will guarantee a portion of the Partnership's obligations to the
Bank under the Loan.  The form of the  Guaranty  Agreement  is  included  in the
Subscription Packet accompanying the Memorandum.

                  Initial Limited Partner.  Stan Johnson,  a resident of Arizona
and an  Affiliate  of the general  partner of the General  Partner.  The Initial
Limited Partner is to be the only limited partner of the Partnership  until such
time as the new Limited Partners are admitted to the Partnership,  at which time
the Initial Limited Partner shall withdraw from the Partnership.

                  Limited Partners.  The Limited Partners are those investors in
the Units  admitted  to the  Partnership  and any person  admitted  as a Limited
Partner in accordance with the provisions of this Agreement.

     Lithotripter.  The extracorporeal shock-wave lithotripter to be acquired by
the Partnership and any replacements therefor or additional  lithotripters to be
purchased by the Partnership.

                                                        -3-

<PAGE>

     Lithotripter   System.   The  mobile  transport   vehicle  and  operational
Lithotripter.

                  Loan.  The  loan  of up to  $487,125  from  the  Bank  to  the
Partnership.  Loan  proceeds will be used by the  Partnership  to (i) acquire an
extracorporeal shockwave lithotripter with options (estimated at $400,000), (ii)
acquire  and upfit a mobile van to  transport  the  lithotripter  (estimated  at
$50,000)  and (iii) pay sales taxes on the purchase of the  Lithotripter  System
(estimated at $37,125).

     Losses.  The net loss (including Net Losses from Capital  Transactions)  of
the  Partnership  for each Year of the  Partnership  as  determined  for federal
income tax purposes.

                  Majority  in Interest  of the  Limited  Partners.  The Limited
Partners who hold more than 50% of the Percentage  Interests in the  Partnership
held by the Limited Partners.

     Memorandum.   The  Confidential   Private   Placement   Memorandum  of  the
Partnership dated January 13, 1999, as amended or as supplemented.

                  Net Gains from Capital Transactions. The gains realized by the
Partnership  as a result of or upon any sale,  exchange,  condemnation  or other
disposition of the capital assets of the Partnership (which assets shall include
Code Section 1231 assets) or as a result of or upon the damage or destruction of
such capital assets.

                  Net Losses from Capital  Transactions.  The losses realized by
the Partnership as a result of or upon any sale, exchange, condemnation or other
disposition of the capital assets of the  Partnership  (which shall include Code
Section 1231 assets) or as a result of or upon the damage or destruction of such
capital assets.

     Offering.  The offer to  potential  investors  of 60 Units  pursuant to the
Memorandum.

     Partners. The General Partner and the Limited Partners, collectively, where
no distinction is required by the context in which the term is used herein.

     Partnership.  Mobile  Kidney  Stone  Centers  of  California  II,  L.P.,  a
California limited partnership.

                  Partnership Cash Flow. For the applicable  period, the excess,
if any,  of (A) the sum of (i) all  gross  receipts  from  any  source  for such
period,  other than from  Partnership  loans,  Capital  Transactions and Capital
Contributions,  and (ii) any funds released by the  Partnership  from previously
established  reserves,  over  (B) the sum of (i) all cash  expenses  paid by the
Partnership  for such  period;  (ii) the amount of all  payments of principal on
loans to the Partnership;  (iii) capital  expenditures of the  Partnership;  and
(iv) such  reasonable  reserves as the General  Partner shall deem  necessary or
prudent to set aside for future repairs,  improvements or equipment  replacement
or additions,  or to meet working capital requirements or foreseen or unforeseen
future liabilities and contingencies of the Partnership; provided, however, that
the amounts referred to in (B)(i), (ii) and (iii) above shall

                                                        -4-

<PAGE>

be taken into  account  only to the extent not funded by Capital  Contributions,
loans or paid out of  previously  established  reserves.  Such term  shall  also
include all other funds deemed  available  for  distribution  and  designated as
"Partnership Cash Flow" by the General Partner.

     Partnership  Interest.  The  interest  of a Partner in the  Partnership  as
defined by the Act and this Agreement.

                  Partnership  Refinancing Proceeds.  The cash realized from the
refinancing of Partnership assets after retirement of any secured loans and less
(i) payment of all expenses  relating to the transaction and (ii)  establishment
of such  reasonable  reserves as the General  Partner  shall deem  necessary  or
prudent to set aside for future repairs,  improvements, or equipment replacement
or additions,  or to meet working capital requirements or foreseen or unforeseen
future liabilities or contingencies of the Partnership.

                  Partnership  Sales Proceeds.  The cash realized from the sale,
exchange,  casualty  or other  disposition  of all or a portion  of  Partnership
assets after the retirement of all secured loans and less (i) the payment of all
expenses  related to the transaction and (ii)  establishment  of such reasonable
reserves as the General Partner shall deem necessary or prudent to set aside for
future repairs,  improvements, or equipment replacement or additions, or to meet
working  capital  requirements or foreseen or unforeseen  future  liabilities or
contingencies of the Partnership.

                  Percentage  Interest.  The  interest  of each  Partner  in the
Partnership,  to be  determined  initially  in the case of a Limited  Partner by
reference to his or her Unit ownership based upon the Limited  Partners  holding
an aggregate 60% Percentage Interest in the Partnership,  with each initial Unit
sold representing an initial 1% interest. The General Partner will initially own
a 40% Percentage  Interest in the Partnership.  A Partner's  Percentage Interest
may be reduced by a future Dilution Offering. The Partners' Percentage Interests
in the Partnership as of the date hereof are as set forth in Schedule A attached
hereto. Any future  adjustments in the Partners'  Percentage  Interests,  due to
future Dilution Offerings or otherwise,  will also be reflected by amendments to
Schedule A.

     Profit. The net income of the Partnership (including Net Gains from Capital
Transactions)  for each Year of the Partnership as determined for federal income
tax purposes.

                  Pro  Rata  Basis.   In   connection   with  an  allocation  or
distribution,  an allocation  or  distribution  in proportion to the  respective
Percentage Interests of the class of Partners to which reference is made.

     Sales Agency  Agreement.  The sales agency agreement  through which MedTech
Investments,  Inc.,  an  Affiliate  of the General  Partner and a  broker-dealer
company  registered with the Securities and Exchange  commission and a member of
the National  Association of Securities  Dealers,  Inc. shall offer and sell the
limited partnership interest of the Partnership pursuant to the Memorandum.

                                                        -5-

<PAGE>

     Sales  Commission.  The $250 sales commission paid to MedTech  Investments,
Inc. for each Unit sold.

                  Service.  The Internal Revenue Service.

                  Units.   The  60  equal  limited  partner   interests  in  the
Partnership offered pursuant to the Memorandum for a price per Unit of $2,500 in
cash, plus a personal guaranty of 1% of the Partnership's  obligations under the
Loan (up to $4,871.25 principal guaranty obligation).

     Year. An annual accounting period ending on December 31 of each year during
the term of the Partnership.

                  7.       CAPITAL CONTRIBUTIONS AND DILUTION OFFERINGS.

                  7.1  General  Partner  Contribution.  On or before the date of
this  Agreement,  the  General  Partner  will  contribute  to the capital of the
Partnership  cash in the amount  equal to 40% (up to $100,000) of the total cash
contributed to the  Partnership by the Partners in the Offering made pursuant to
the Memorandum.

                  7.2 Limited Partner Contribution.  Each Limited Partner hereby
agrees to contribute and shall  contribute to the capital of the  Partnership on
the date of his or her  admission to the  Partnership  the cash amount set forth
opposite his or her name on Schedule A attached hereto.

     7.3 No Interest.  Except as otherwise provided herein, no interest shall be
paid on any contribution to the capital of the Partnership.

                  7.4 Dilution  Offerings.  If the General Partner,  in its sole
discretion,  determines that it is in the best interest of the Partnership,  the
General Partner may, from time to time, offer, sell and issue, for and on behalf
of the Partnership,  additional limited partnership interests in the Partnership
(a  "Dilution  Offering")  to  investors  who are not already  Limited  Partners
("Qualified  Investors").  The primary purpose of any Dilution Offering would be
to raise additional capital for any legitimate  Partnership purpose as set forth
in Article 4. Any limited partnership  interests offered by the Partnership in a
Dilution  Offering  shall  be sold in the  manner  and  according  to the  terms
prescribed in the sole  discretion of the General  Partner;  provided,  however,
that any additional limited partnership interests offered in a Dilution Offering
will be sold for a price no lower than the highest price for which proportionate
limited  partnership  interests in the Partnership  have been previously sold by
the Partnership unless otherwise determined by a vote of the General Partner and
a Majority in Interest of the Limited Partners.  Any sale of additional  limited
partnership  interests  will  result  in  the  proportionate   dilution  of  the
Percentage Interests of the existing Partners. Notwithstanding the above, in the
event of a  Dilution  Offering,  the  General  Partner  may  elect,  in its sole
discretion,   to  prevent   dilution  of  its  Percentage   Interest  by  either
contributing  additional  capital to the  Partnership  or purchasing  additional
limited partnership  interests in any Dilution Offering.  Limited Partners shall
have no right to purchase  additional  limited partner interests in any Dilution
Offering or to make

                                                        -6-

<PAGE>

additional capital contributions or take any other action to prevent dilution of
their Percentage Interest. Any investor acquiring a limited partnership interest
in a Dilution  Offering shall agree to be bound by the terms of this  Agreement,
and shall be automatically admitted as a Limited Partner of the Partnership. Any
adjustment  in the  Partners'  Percentage  Interests  resulting  from a Dilution
Offering shall be set forth on an amended Schedule A to be attached hereto.

                  8.       GUARANTIES.
                           ----------

                  Each Partner agrees to execute and deliver to the  Partnership
on the date of his or her admission to the  Partnership a Guaranty in the amount
set forth opposite his or her name on Schedule A attached hereto.

                  9.       CONDITIONS TO THE CAPITAL CONTRIBUTIONS OF CERTAIN
                           --------------------------------------------------
                           LIMITED PARTNERS.
                           ----------------

                  The  obligations  of  any  Limited  Partners  acquiring  their
Partnership  Interests  in the  Offering  or a  Dilution  Offering  to make cash
Capital   Contributions   hereunder  are  subject  to  the  condition  that  the
representations, warranties, agreements and covenants of the General Partner set
forth in Article 10 of this  Agreement are and shall be true and correct or have
been and will have been complied with in all material  respects on the date such
Capital  Contributions  are  required to be made,  except to the extent that any
such representation or warranty expressly pertains to an earlier date.

                  10.      REPRESENTATIONS, WARRANTIES AND COVENANTS OF THE
                           ------------------------------------------------
                           GENERAL PARTNER.
                           ---------------

          10.1 The General Partner hereby represents and warrants to the Limited
     Partners  that:  (a) The  Partnership  is a limited  partnership  formed in
     accordance with and validly existing under the Act and the other applicable
     laws of the State of California;

                  (b) The interests in the  Partnership of the Limited  Partners
         will have been duly  authorized  or created and validly  issued and the
         Limited  Partners shall have no personal  liability to contribute money
         to the  Partnership  other than the amounts agreed to be contributed by
         them in the  manner  and on the  terms  set  forth  in this  Agreement,
         subject, however, to such limitations as may be imposed under the Act;

                  (c) Except as disclosed  in the  Memorandum  or  documentation
         prepared in connection with a Dilution Offering,  no material breach or
         default adverse to the Partnership  exists under the terms of any other
         material agreement affecting the Partnership; and

               (d) The  General  Partner  is a  California  limited  partnership
          formed and existing under the laws of the State of California.

          10.2 The General  Partner  hereby  covenants  to the Limited  Partners
     that:

                                                        -7-

<PAGE>

               (a) It will at all times act in a fiduciary  manner with  respect
          to the Partnership and the Limited Partners;

               (b)  Except as  provided  in  Article  19,  it will  serve as the
          General Partner of the Partnership until the Partnership is terminated
          without reconstitution; and

                  (c) It will cause the  Partnership  to carry  adequate  public
         liability,  property  damage and other insurance as is customary in the
         business to be engaged in by the Partnership.

                  11.      ADMISSION OF LIMITED PARTNERS.
                           -----------------------------

                  The  General  Partner may permit the offer and sale of limited
partnership  interests on the terms and conditions provided in the Memorandum or
future  Dilution  Offerings and may admit persons  subscribing  for interests as
Limited  Partners in the  Partnership  on the terms and  conditions set forth in
this Article 11.

                  (a) The General  Partner  shall have approved of the admission
         of said person in writing on such terms and  conditions  as the General
         Partner shall determine;

                  (b)  Said  person  shall  have  executed  such   documents  or
         instruments  as the General  Partner may deem necessary or desirable to
         effect his or her admission as a Limited Partner;

               (c) Said person shall have  accepted and adopted all of the terms
          and provisions of this Agreement, as then amended;

                  (d)  Said  person  (if a  corporation)  shall  deliver  to the
         General  Partner  a  certified  copy of a  resolution  of its  Board of
         Directors  authorizing  it to become a Limited  Partner under the terms
         and conditions of this Agreement; and

                  (e) Said person,  upon request by the General  Partner,  shall
         pay such reasonable  expenses as may be incurred in connection with its
         admission as a Limited Partner.

                  12.      CAPITAL ACCOUNTS.
                           ----------------

                  A Capital  Account shall be  established  for each Partner and
shall at all times be determined  and  maintained  in accordance  with the Final
Treasury  Regulations  under  Section  704(b)  of the  Code,  as the same may be
amended.  A Partner  shall not be entitled  to  withdraw  any part of his or her
Capital Account or to receive any distribution  from the Partnership,  except as
provided in Articles 14 and 25.

                  (a)      Each Partners' Capital Account shall be increased by:

                                                        -8-

<PAGE>

                         (i)  The  amount  of his or  her  Capital  Contribution
                    pursuant to Article 7; and

                         (ii) The  amount  of  Profits  allocated  to him or her
                    pursuant to Article 13; and

                           (iii) The Partner's pro rata share (determined in the
                  same  manner as such  Partner's  share of  Profits  and Losses
                  allocated pursuant to Article 13 hereof) of any income or gain
                  exempt from tax.

                  (b)      Each Partner's Capital Account shall be decreased by:

                         (i)  The  amount  of  Losses  allocated  to  him or her
                    pursuant to Article 13; and

                         (ii) The amount of Partnership  Cash Flow,  Partnership
                    Sales   Proceeds  and   Partnership   Refinancing   Proceeds
                    distributed to him or her pursuant to Article 14; and

                           (iii)  The  Partner's  pro rata  share  of any  other
                  expenditures  of the  Partnership  which are not deductible in
                  computing  Partnership  Profits  or  Losses  and which are not
                  added to the tax basis of any Partnership property, including,
                  without   limitation,   expenditures   described   in  Section
                  705(a)(2)(B) of the Code. The Partner's pro rata share of such
                  expenditures  shall be  determined  in the same manner as such
                  Partner's  share of Profits and Losses  allocated  pursuant to
                  Article 13.

                                                        -9-

<PAGE>

                  13.      ALLOCATIONS

                  (a)  Profits  and  Losses.  The  Profits  and  Losses  of  the
         Partnership  shall be allocated  among the Partners in accordance  with
         their  respective  Percentage  Interests.  In  allocating  Profits  and
         Losses,  Net Gains and  Losses  from  Capital  Transactions  (a part of
         Profits and Losses), if any, shall be allocated first.

                  (b)  Partnership  Minimum Gain  Chargeback.  If there is a net
         decrease in  Partnership  Minimum  Gain during any Year,  each  Partner
         shall be specially  allocated items of Partnership  income and gain for
         such Year (and, if necessary,  subsequent  Years) in an amount equal to
         such Partner's  share of the net decrease in Partnership  Minimum Gain,
         determined   in   accordance   with   Treasury    Regulations   Section
         1.704-2(g)(2).  Allocations made pursuant to the previous sentence will
         be  made  in  proportion  to  the  respective  amounts  required  to be
         allocated to each Partner  pursuant to that section of the Regulations.
         This  provision  relating to  Partnership  Minimum Gain  Chargebacks is
         intended to comply with Treasury  Regulations  Section  1.704-2(f)  and
         will be  interpreted  and  applied  in a manner  consistent  with  that
         Regulation.

                  (c)  Partner  Minimum  Gain  Chargeback.  If  there  is a  net
         decrease in Partner Minimum Gain attributable to a Partner  Nonrecourse
         Debt  during  any Year,  each  Partner  who has a share of the  Partner
         Minimum Gain  attributable  to such Partner  Nonrecourse  Debt shall be
         specially  allocated items of Partnership income and gain for such Year
         (and,  if  necessary,  subsequent  Years)  in an  amount  equal to such
         Partner's   share  of  the  net   decrease  in  Partner   Minimum  Gain
         attributable to such Partner  Nonrecourse  Debt, to the extent required
         and  determined  in  accordance  with  Treasury   Regulations   Section
         1.704-2(i)(4).  Allocations  pursuant to the previous  sentence will be
         made in proportion to the respective  amounts  required to be allocated
         to each  Partner  pursuant  to that  section of the  Regulations.  This
         provision  relating to Partner Minimum Gain  Chargebacks is intended to
         comply with Regulation  Section  1.704-2(i)(4)  and will be interpreted
         and applied in a manner consistent with that Regulation.

                  (d)  Qualified  Income  Offset.  If any  Partner  unexpectedly
         receives  any  adjustment,  allocation  or  distribution  described  in
         Treasury Regulations Section 1.704- 1(b)(2)(ii)(d)(4) through (6) which
         causes or increases a deficit balance in such Partner's Capital Account
         (adjusted  for  this  purpose  in  the  manner   provided  in  Treasury
         Regulations Section 1.704-1(b)(2)(ii)(d)),  items of Partnership income
         and gain shall be specially allocated to each such Partner in an amount
         and manner  sufficient  to  eliminate,  to the extent  required  by the
         Regulations,  the deficit Capital Account of such Partner as quickly as
         possible,  provided that an  allocation  pursuant to this Article 13(d)
         shall be made if and only to the extent that such Partner  would have a
         deficit  Capital  Account after all other  allocations  provided for in
         this Article 13 have been  tentatively  made as if this  Article  13(d)
         were  not  in  the  Agreement.  This  provision  is  intended  to  be a
         "qualified income offset," as defined in Treasury  Regulations  Section
         1.704-1(b)(2)(ii)(d),  such Regulation being specifically  incorporated
         herein by reference.

                                                       -10-

<PAGE>

                  (e) Sales Commission.  The Sales Commission shall be allocated
         to the  Units  which  are  not  held  by the  General  Partner  and its
         Affiliates  and are  acquired  in the  Offering  in  proportion  to the
         respective capital contributions  represented by such Units (i.e., $250
         in Sales  Commissions per each such Unit).  The purpose of this Article
         13(e)  is to  allocate  the  Sales  Commission  to those  Partners  who
         actually bore the burden of paying the Sales Commission.

                  (f)  Allocations  Between  Transferor and  Transferee.  In the
         event of the transfer (other than the pledges of the General  Partner's
         interest  permitted  by Article 19 or  Permitted  Pledges  described in
         Article  17.2(b))  of all or  any  part  of a  Partner's  interest  (in
         accordance with the provisions of this Agreement) in the Partnership at
         any time other  than at the end of a Year,  or the  admission  of a new
         Partner  (in  accordance  with  the  terms  of  this  Agreement),   the
         transferring  Partner  or new  Partner's  share  of  the  Partnership's
         income,  gain,  loss,  deductions  and  credits,  as computed  both for
         accounting  purposes  and for  federal  income tax  purposes,  shall be
         allocated between the transferor Partner and the transferee Partner (or
         Partners),  or the new Partner and the other Partners,  as the case may
         be, in the same  ratio as the  number of days in such Year  before  and
         after the date of the transfer or admission; provided, however, that if
         there  has  been a sale  or  other  disposition  of the  assets  of the
         Partnership  (or any part thereof)  during such Year,  then the General
         Partner may elect, in its sole discretion,  to treat the periods before
         and after the date of the transfer or  admission as separate  Years and
         allocate the Partnership's net income,  gain, net loss,  deductions and
         credits for each of such deemed  separate  Years.  Notwithstanding  the
         foregoing, the Partnership's "allocable cash basis items," as that term
         is used in Section  706(d)(2)(B)  of the Code,  shall be  allocated  as
         required  by  Section   706(d)(2)  of  the  Code  and  the  regulations
         thereunder.

                  (g) Tax  Withholding.  The Partnership  shall be authorized to
         pay, on behalf of any  Partner,  any amounts to any  federal,  state or
         local taxing  authority,  as may be necessary  for the  Partnership  to
         comply with tax withholding  provisions of the Code or the other income
         tax or  revenue  laws  of any  taxing  authority.  To  the  extent  the
         Partnership  pays any such  amounts  that it may be  required to pay on
         behalf  of  a  Partner,  such  amounts  shall  be  treated  as  a  cash
         distribution  to such  Partner  and shall  reduce the amount  otherwise
         distributable to such Partner.

                  14.      DISTRIBUTIONS.
                           -------------

                  (a)  Distribution of Partnership  Cash Flow.  Partnership Cash
         Flow shall be distributed to the Partners  within 60 days after the end
         of each Year, or earlier in the discretion of the General  Partner,  in
         proportion  to their  respective  Percentage  Interests  at the time of
         distribution.

               (b)   Distribution  of  Partnership   Refinancing   Proceeds  and
          Partnership  Sales  Proceeds.  Partnership  Refinancing  Proceeds  and
          Partnership Sales Proceeds shall be

                                                       -11-

<PAGE>

         distributed to the Partners  within 60 days of the Capital  Transaction
         giving  rise to such  proceeds,  or  earlier in the  discretion  of the
         General Partner, in proportion to their respective Percentage Interests
         at the time of distribution.

                  (c)  Distribution  in  Liquidation.  Upon  liquidation  of the
         Partnership,  all of the  Partnership's  property  shall  be  sold  and
         Profits and Losses allocated accordingly. Proceeds from the liquidation
         of the Partnership shall be distributed in accordance with Article 25.

                  l5.      RIGHTS AND OBLIGATIONS OF LIMITED PARTNERS.
                           ------------------------------------------

                  15.1  Management.  The Limited Partners shall not take part in
the management of the business,  nor transact any business for the  Partnership,
nor  shall  they  have  power  to  sign  for or to  bind  the  Partnership.  The
Partnership may,  however,  contract with one or more Limited Partners to act as
the local medical director(s) of the Lithotripter System. No Limited Partner may
withdraw from the Partnership except as expressly permitted herein.

                  15.2 Operation of Lithotripter  System.  The Limited  Partners
shall not  operate  or  utilize  the  Partnership  Lithotripter  System or other
Partnership  equipment except pursuant to (i) an agreement with the Partnership;
or (ii) any other arrangement specifically approved by the General Partner.

                  15.3 Outside Activities.  The Limited Partners agree that they
owe fiduciary  duties to the  Partnership  and, as a  consequence,  each Limited
Partner (that is not the General Partner or an Affiliate of the General Partner)
agrees that (s)he shall not engage in "Outside Activities" (as defined below) in
the "Market  Area" (as defined  below)  while(s)he  is a Limited  Partner in the
Partnership  and shall  otherwise be subject to the  provisions  of this Article
15.3.  The phrase  "Outside  Activities"  means  directly or indirectly  owning,
leasing or  subleasing  a  lithotripter  (or any similar  equipment or competing
devices  used  for  treating  renal  or  biliary  stone  disease)  or any  other
therapeutic  equipment  acquired by the Partnership;  provided that an ownership
interest in the General Partner or an Affiliate of the General Partner shall not
constitute an Outside  Activity.  Prohibited  indirect  ownership  shall include
without  limitation  the  direct or  indirect  ownership  of any  interest  in a
business  venture  (through stock  ownership,  partnership  interest  ownership,
ownership by or through a close family  member,  or as otherwise  determined  in
good faith by the General  Partner)  involving the ownership,  purchase,  lease,
sublease,  promotion,  management  or  operation of a  lithotripter  (or similar
equipment or competing devices used for treating renal or biliary stone disease)
or other competing  device or equipment,  unless the General Partner  determines
that such  activity  by the  Limited  Partners  is not  detrimental  to the best
interests of the Partnership;  provided,  however, that the General Partner may,
in its sole  discretion,  waive the provisions of this Section 15.3 with respect
to any ownership  interest of a Limited Partner in an Outside Activity  acquired
before the date hereof.  Notwithstanding  the above, a Limited Partner shall not
be  prohibited  from owning less than 1% of the capital stock  (calculated  on a
fully diluted basis) of a corporation whose stock is publicly owned or regularly
traded on any public exchange.

                  Upon  the  termination  or  transfer  of a  Limited  Partner's
interest in the  Partnership  for any reason,  including a transfer  pursuant to
Article 18.3 hereof, the withdrawing  Limited Partner shall not, for a period of
two (2) years following the date of withdrawal, engage in any Outside Activities

                                                       -12-

<PAGE>

in any "Market Area" in which the Partnership is transacting  business or within
the prior twelve months has transacted  business (the "Restricted  Facilities").
For the purposes of this Article 15.3, the term "Market Area" shall mean (i) the
area within a fifty (50) mile  radius of any  Restricted  Facility,  but if such
area is determined by a court of competent jurisdiction to be too broad, then it
shall  mean (ii) the area  within a thirty  (30) mile  radius of any  Restricted
Facility, but if such area is determined by a court of competent jurisdiction to
be too broad then it shall mean (iii) the area within a fifteen (15) mile radius
of any Restricted Facility.

                  In the event a Limited Partner wishes and intends to engage in
an Outside  Activity in a Market Area, he or she must provide  written notice of
such intent to the General  Partner  prior to engaging in the Outside  Activity.
The  written  notice  shall be deemed an  election  by the  Limited  Partner  to
withdraw from the Partnership (the "Notice of  Withdrawal"),  and shall give the
General  Partner the purchase  rights as provided in Article 18.3 hereof.  After
the Notice of Withdrawal,  the former  Limited  Partner may engage in an Outside
Activity in the Market Area only after waiting the period of two years specified
in this  Article  15.3.  In the  event of  breach  of the  waiting  period,  the
Partnership  shall be entitled  to any remedy at law or equity  with  respect to
such breach, including without limitation an injunction or suit for damages.

                  If a Limited  Partner during his or her  participation  in the
Partnership  engages in an  Outside  Activity  in a Market  Area  without  first
notifying  the General  Partner in violation of this Article  15.3,  the Limited
Partner  shall be deemed to have  given a Notice of  Withdrawal  on the date the
General Partner first becomes aware of the Limited Partner's Outside Activity in
the Market Area.  Upon  receiving a Limited  Partner's  Notice of  Withdrawal or
equivalent  thereof,  the Partnership may invoke the purchase rights provided in
Article  18.3  and  shall be  entitled  to any  other  remedy  at law or  equity
including without limitation an injunction or suit for damages.

                  15.4  Disclosure  of  Confidential  Information.  Each Limited
Partner acknowledges and agrees that his or her participation in the Partnership
under this Agreement necessarily involves his or her understanding of and access
to certain trade secrets and other  confidential  information  pertaining to the
business of the Partnership.  Accordingly,  each Limited Partner (other than the
General   Partner  and  its  Affiliates  that  may  also  hold  Limited  Partner
Partnership  Interests) agrees that at all times during his or her participation
in the Partnership as a Limited Partner and thereafter, (s)he will not, directly
or indirectly, without the express written authority of the Partnership,  unless
required by law or directed by a applicable legal authority having  jurisdiction
over  the  Limited  Partner,  disclose  or use for the  benefit  of any  person,
corporation  or other  entity  (other  than  the  Partnership),  or the  Limited
Partner, (i) any trade, technical, operational, management or other secrets, any
patient or customer  lists or other  confidential  or secret data,  or any other
proprietary,  confidential or secret  information of the Partnership or (ii) any
confidential information concerning any of the financial arrangements, financial
condition,  hospital or  physician  contracts,  third party payor  arrangements,
quality assurance and outcome analysis programs, competitive status, customer or
supplier matters, internal organizational matters, technical abilities, or other
business affairs of or relating to the Partnership.  The Limited Partners (other
than the General  Partner and its Affiliates  that may also hold Limited Partner
Partnership Interests) acknowledge that all of the foregoing

                                                       -13-

<PAGE>

constitutes  proprietary  information,  which is the  exclusive  property of the
Partnership.  In the event of breach of this Article 15.4 as  determined  by the
General  Partner,  the  Partnership  shall be  entitled  to any remedy at law or
equity with respect to such breach, including without limitation,  an injunction
or suit for damages.

                  16.      LIMITED LIABILITY.
                           -----------------

                  No Limited Partner shall be required to make any  contribution
to the  capital of the  Partnership  except as set forth in Article 7, nor shall
any Limited  Partner in his or her capacity as such,  be bound by, or personally
liable for, any expense,  liability or obligation of the  Partnership  except to
the extent of his or her (i) interest in the  Partnership;  (ii)  Guaranties  of
Partnership  obligations;  and (iii) obligation to return  distributions made to
him or her under certain circumstances as required by the Act.

                  17.      TRANSFER OF INTERESTS AND ADMISSION OF PARTNERS.
                           -----------------------------------------------

                  17.1     Transferability.
                           ---------------

                  (a) The  term  "transfer"  when  used in this  Agreement  with
         respect to a Partnership  Interest includes a sale,  assignment,  gift,
         pledge,  exchange  or any other  disposition  (but does not include the
         issuance of new Partnership Interests pursuant to a Dilution Offering);

               (b) Except as  otherwise  provided  herein,  the General  Partner
          shall not at any time transfer or assign its interest or obligation as
          General Partner;

                  (c) The Partnership  Interest of any Limited Partner shall not
         be  transferred,  in whole or in part,  except in  accordance  with the
         conditions and limitations set forth in Articles 17.2 or 18;

                  (d) The  transferee of a Partnership  Interest by  assignment,
         operation of law or otherwise,  shall have only the rights,  powers and
         privileges  enumerated in Article 17.3 or otherwise provided by law and
         may not be admitted to the  Partnership as a Limited  Partner except as
         provided in Article 17.4 or as a General  Partner except as provided in
         Article 17.5;

               (e)  Notwithstanding  any provision  herein to the contrary,  the
          Partnership  Agreement  shall  in no  way  restrict  the  issuance  or
          transfers of stock of the General Partner; and

               (f)  Notwithstanding  any provision  herein to the contrary,  the
          issuance of Partnership  Interests pursuant to a Dilution Offering and
          the admission of new

                                                       -14-

<PAGE>

         Limited Partners  pursuant to a Dilution  Offering shall be governed by
         the provisions of Article 7.4 of this Agreement.

                  17.2     Restrictions on Transfers by Limited Partners.
                           ---------------------------------------------

                  (a) All or part of a Partnership  Interest may be  transferred
         by a  Limited  Partner  only  with the prior  written  approval  of the
         General  Partner,  which  approval may be granted or denied in the sole
         discretion of the General Partner.

                  (b) The General  Partner  shall not approve any  transfer of a
         Partnership  Interest,  except a pledge of any Partnership  Interest by
         the General Partner to any bank,  insurance  company or other financial
         institution to secure payment of indebtedness  (a "Permitted  Pledge"),
         or otherwise  unless the proposed  transferee  shall have furnished the
         General Partner with a sworn statement that:

                         (i) The proposed  transferee proposes to acquire his or
                    her Partnership Interest as a principal,  for investment and
                    not with a view to resale or distribution;

                           (ii) The proposed  transferee meets such requirements
                  regarding sophistication,  income and net worth as required by
                  applicable state and federal securities laws;

                           (iii) The proposed  transferee has met such net worth
                  and income  suitability  standards as have been established by
                  the General Partner;

                           (iv)  The   proposed   transferee   recognizes   that
                  investment in the Partnership  involves  certain risks and has
                  taken  full  cognizance  of and  understands  all of the  risk
                  factors related to the purchase of a Partnership Interest; and

                         (v)  The   proposed   transferee   has  met  all  other
                    requirements   of  the  General  Partner  for  the  proposed
                    transfer.

                  (c) Other than in the case of a Permitted  Pledge,  a transfer
         of a  Partnership  Interest  may be made  only  if,  prior  to the date
         thereof,  the Partnership  upon request receives an opinion of counsel,
         satisfactory in form and substance to the General Partner, that neither
         the offering nor the proposed transfer will require  registration under
         federal or applicable state securities laws or regulations.

     17.3 Rights of Transferee. Unless admitted to the Partnership in accordance
with Article 17.4, the transferee of a Partnership Interest or a part thereof or
any right, title or interest

                                                       -15-

<PAGE>

therein shall not be entitled to any of the rights, powers, or privileges of his
or her  predecessor in interest,  except that (s)he shall be entitled to receive
and be credited or debited with his or her  proportionate  share of  Partnership
income, gains, Profits, Losses, deductions, credits or distributions.

                  17.4  Admission  of  Limited  Partners.  Except  as  otherwise
provided in Article 18, the General Partner, or the transferee of all or part of
the Partnership  Interest of either a General Partner or a Limited Partner,  may
be admitted to the  Partnership  as a Limited  Partner  upon  furnishing  to the
General Partner all of the following:

                  (a) The  written  approval of a Majority in Interest of all of
         the Limited  Partners  (except the assignor  Partner),  or the assignor
         Partner  alone,  which  approval  may be  granted or denied in the sole
         discretion of such Partners or Partner (as the case may be);

               (b) The written approval of the General  Partner,  which approval
          may be  granted  or  denied  in the  sole  discretion  of the  General
          Partner;

                  (c) Acceptance, in a form satisfactory to the General Partner,
         of all the  terms  and  conditions  of  this  Agreement  and any  other
         documents  required in connection with the operation of the Partnership
         pursuant to the terms of this Agreement;

               (d) A properly executed power of attorney substantially identical
          to that contained in Article 38;

               (e) Such other  documents  or  instruments  as may be required in
          order to effect his or her admission as a Limited Partner; and

               (f)  Payment of such  reasonable  expenses  as may be incurred in
          connection with his or her admission as a Limited Partner.

     17.5 Admission of General Partners. A Limited Partner, or the transferee of
     all or part of the  Partnership  Interest  of the General  Partner,  may be
     admitted to the  Partnership  as a general  partner upon  furnishing to the
     General Partner all of the following:

                  (a) The  written  consent of both the  General  Partner  and a
         Majority  in Interest of the  Limited  Partners,  which  consent may be
         granted or denied in the sole discretion of the Partners;

                  (b) Such financial statements,  guarantees or other assurances
         as the General  Partner  may require  with regard to the ability of the
         proposed  general  partner to fulfill the  financial  obligations  of a
         general partner hereunder;

                                                       -16-

<PAGE>

                  (c) Acceptance,  in form  satisfactory to the General Partner,
         of all the  terms  and  provisions  of  this  Agreement  and any  other
         documents  required in connection with the operation of the Partnership
         pursuant to the terms of this Agreement;

               (d) A certified  copy of a  resolution  of its Board of Directors
          (if it is a corporation)  authorizing  it to become a general  partner
          under the terms and conditions of this Agreement;

               (e) A power of attorney substantially identical to that contained
          in Article 38;

               (f) Such other  documents  or  instruments  as may be required in
          order to effect its admission as a general partner; and

               (g)  Payment of such  reasonable  expenses  as may be incurred in
          connection with its admission as a general partner.

                  Notwithstanding  the above,  a transferee  that controls or is
controlled by the General Partner or one or more of its Affiliates that receives
all or part of the  Partnership  Interest of the General Partner may be admitted
to the  Partnership as a general  partner upon complying with all the provisions
of Article  17.5  except for  subparagraph  17.5(a).  As long as the  transferee
either  controls or is controlled  by the General  Partner or one or more of its
Affiliates,  no  Limited  Partner  consents  will  be  required  to  admit  such
transferee as a general partner to the Partnership.

                  17.6  Amendment  of  Certificate  of Limited  Partnership  and
Qualification.   The  General   Partner  shall  take  all  steps  necessary  and
appropriate to prepare and record any  amendments to the  Certificate of Limited
Partnership, as may be necessary or appropriate from time to time to comply with
the requirements of the Act, including,  without limitation,  upon the admission
to the Partnership of any general partner  pursuant to the provisions of Article
17.5, and may for this purpose  exercise the power of attorney  delivered to the
General Partner pursuant to Article 17.5 or 38. In addition, the General Partner
shall take all steps necessary and appropriate to prepare and record any and all
documents  necessary to qualify the Partnership to do business in  jurisdictions
where the Partnership is doing business,  and may for this purpose  exercise the
power of attorney  delivered to the General  Partner  pursuant to Articles 17.4,
17.5 or 38.

                  17.7 Fundamental  Changes.  In the event a plan is approved by
the General Partner and a Majority in Interest of the Limited Partners providing
for the  merger or  consolidation  of the  Partnership  with  another  person or
entity,  or the sale of all or substantially  all of the Partnership  Interests,
including  without  limitation the exchange of Partnership  Interests for equity
interests  in  another  person or entity or for cash or other  consideration  or
combination  thereof,  then and in such  event,  the Limited  Partners  shall be
obligated to take or refrain  from  taking,  as the case may be, such actions as
the plan may provide, including, without limitation, executing such instruments,
and

                                                       -17-

<PAGE>

providing such information as the General Partner shall reasonably request.  Any
plan  described  in this  Article  17.7  may also  effect  an  amendment  to the
Partnership Agreement or the adoption of a new partnership agreement as provided
in Section  15678.2(e)  of the Act.  The plan may also  provide that the General
Partner  and  its  Affiliates  shall  receive  fees  for  services  rendered  in
connection  with  the  operation  of the  Partnership  or any  successor  entity
following  the  consummation  of the  transactions  described  in the plan,  and
neither the  Partnership nor the Partners shall have any right by virtue of this
Agreement in the income derived therefrom. Any securities or other consideration
to be distributed  to the Partners  pursuant to the plan shall be distributed in
the  manner  set forth in Article  25(c) as though  the  Partnership  were being
liquidated.  For this purpose only,  the fair market value of the  securities or
other  consideration  to be  received  pursuant  to the plan shall be treated as
"Profits"  and the capital  accounts of the  Partners  shall be increased in the
manner  provided  in Article  12(a)(ii).  No Partner  shall be  entitled  to any
dissent,  appraisal or similar rights in connection with a plan  contemplated by
this Article 17.7.

                  17.8 Withdrawal of Initial Limited Partner.  Upon the date the
first Limited  Partner is admitted to the Partnership in accordance with Article
11 of this  Agreement,  the Initial  Limited  Partner  shall  withdraw  from the
Partnership,  and thereupon his Capital  Contribution  shall be returned and his
Partnership Interest canceled and reallocated to the Limited Partners.

                  18.      OPTIONAL PURCHASE OF LIMITED PARTNERSHIP INTERESTS
                           --------------------------------------------------
                           ON CERTAIN EVENTS.
                           -----------------

                  18.1 Death. Upon the death of a Limited Partner,  the deceased
Limited  Partner's   executor,   administrator,   or  other  legal  or  personal
representative  shall give written  notice of that fact to the General  Partner.
The General Partner shall have the option to purchase at the Closing (as defined
below) the Partnership Interest of the deceased Limited Partner (whose executor,
administrator  or other  legal or  personal  representative  shall  then  become
obligated  to sell such  Partnership  Interest) at the price  determined  in the
manner  provided  in  Article  18.7  of  this  Agreement  and on the  terms  and
conditions provided in Article 18.8 of this Agreement. The General Partner shall
have a period of thirty (30) days  following  the date of notice of the death of
the Limited Partner (the "Option  Period") within which to notify in writing the
deceased Limited  Partner's  executor,  administrator or other legal or personal
representative,  whether the General Partner wishes to purchase all or a portion
of the  Partnership  Interest of the deceased  Limited  Partner.  If the General
Partner  does not elect to  purchase  the  entire  Partnership  Interest  of the
deceased  Limited  Partner before the expiration of the Option Period and in the
manner provided  herein,  the portion of the Partnership  Interest not purchased
shall be held by the deceased Limited Partner's executor, administrator or other
legal  representative  pursuant  to the  terms of this  Agreement.  The  General
Partner, in its sole discretion,  may elect to assign its rights to purchase the
Partnership  Interest of the deceased Limited Partner under this Article 18.1 to
the Partnership and, in such case, the Partnership shall have the same rights as
provided for the General Partner in this Article 18.1.

     18.2  Bankruptcy,  Insolvency or  Assignment  for Benefit of Creditors of a
Limited Partner. In the event that an involuntary or voluntary  proceeding under
the Federal Bankruptcy

                                                       -18-

<PAGE>

Code, as amended, is filed for or against any Limited Partner, or if any Limited
Partner shall make an  assignment  for the benefit of his  creditors,  or if any
Limited  Partner has a receiver or custodian  appointed  for his assets,  or any
Limited Partner generally fails to pay his debts when due, the insolvent Limited
Partner shall give written  notice (the "Notice of  Insolvency")  to the General
Partner of the  commencement  of any such  proceeding or the  occurrence of such
event  within  five days of the  first  notice  to him of such  commencement  or
occurrence of such event.  The General Partner shall have the option to purchase
at the Closing  (as defined  below) the  Partnership  Interest of the  insolvent
Limited Partner (which the insolvent Limited Partner or his trustee,  custodian,
receiver or other  personal or legal  representative,  as the case may be, shall
then become obligated to sell) at the price determined in the manner provided in
Article  18.7 of this  Agreement  and on the terms and  conditions  provided  in
Article  18.8 of this  Agreement.  The  General  Partner  shall have a period of
thirty (30) days  following  the date of the Notice of  Insolvency  (the "Option
Period") within which to notify in writing the insolvent  Limited Partner or his
trustee, custodian, receiver, or other legal or personal representative, whether
the  General  Partner  wishes to  purchase  all or a portion of the  Partnership
Interest of the insolvent Limited Partner. If the General Partner does not elect
to purchase the entire  Partnership  Interest of the insolvent  Limited  Partner
before the  expiration of the Option Period and in the manner  provided  herein,
the  portion of the  Partnership  Interest  not  purchased  shall be held by the
insolvent Partner, his trustee,  custodian,  receiver or other legal or personal
representative pursuant to the terms of this Agreement.  The General Partner, in
its sole discretion,  may elect to assign its rights to purchase the Partnership
Interest  of an  insolvent  Limited  Partner  under  this  Article  18.2  to the
Partnership  and, in such case,  the  Partnership  shall have the same rights as
provided for the General Partner in this Article 18.2.

                  18.3 Breach of Article 15.3. In the event the General  Partner
either  receives a Notice of  Withdrawal as provided in Article 15.3 or receives
notice of a breach of Article 15.3 by or with respect to a Limited  Partner (the
"Competing  Limited  Partner"),  the  General  Partner  may  elect,  in its sole
discretion,  to treat such event as a default  under this  Agreement and enforce
the  provisions of this Article 18.3. If the General  Partner  elects to enforce
the  provisions  of this Article  18.3,  the General  Partner shall give written
notice of such  election  (the  "Notice of Default")  to the  Competing  Limited
Partner  within 180 days of the date the  General  Partner  first  received  the
Notice of  Withdrawal or notice of the  defaulting  event.  The General  Partner
shall  have the  option to  purchase  at the  Closing  (as  defined  below)  the
Partnership  Interest of the  Competing  Limited  Partner  (which the  Competing
Limited Partner shall then become  obligated to sell) at the price determined in
the manner  provided  in  Article  18.7 of this  Agreement  and on the terms and
conditions provided in Article 18.8 of this Agreement. The General Partner shall
have a period of  thirty  (30) days  following  the date it sends the  Notice of
Default (the "Option  Period")  within which to notify in writing the  Competing
Limited Partner,  whether the Partnership wishes to purchase all or a portion of
the  Partnership  Interest  of the  Competing  Limited  Partner.  If the General
Partner  does not elect to  purchase  the  entire  Partnership  Interest  of the
Competing  Limited Partner before the expiration of the Option Period and in the
manner provided  herein,  the portion of the Partnership  Interest not purchased
shall be held by the  Competing  Limited  Partner  pursuant to the terms of this
Agreement. The General Partner, in its sole discretion,  may elect to assign its
rights to purchase the Partnership

                                                       -19-

<PAGE>

Interest  of a  Competing  Limited  Partner  under  this  Article  18.3  to  the
Partnership  and, in such case,  the  Partnership  shall have the same rights as
provided for the General Partner in this Article 18.3.

                  18.4  Domestic  Proceeding.  In the  event  that a spouse of a
Limited Partner  commences  against a Limited  Partner,  or a Limited Partner is
named in, a Domestic  Proceeding,  the Limited Partner shall give written notice
(the "Notice of Domestic Proceeding") to the General Partner of the commencement
of any such  proceeding  within  five  days of the  first  notice to him of such
commencement.  The  General  Partner  shall have the option to  purchase  at the
Closing  (as defined  below) the  Partnership  Interest  of the Limited  Partner
involved in the Domestic Proceeding (which the Limited Partner shall then become
obligated to sell),  at the price  determined in the manner  provided in Article
18.7 of this Agreement and on the terms and conditions  provided in Article 18.8
of this  Agreement.  The General Partner shall have a period of thirty (30) days
following the date of the Notice of Domestic  Proceeding  (the "Option  Period")
within which to notify in writing the Limited  Partner  involved in the Domestic
Proceeding,  whether the General  Partner wishes to purchase all or a portion of
the Partnership  Interest of such Limited  Partner.  If the General Partner does
not elect to purchase the Partnership  Interest of the Limited Partner  involved
in the Domestic Proceeding before the expiration of the Option Period and in the
manner provided  herein,  the portion of the Partnership  Interest not purchased
shall be held by such Limited  Partner  pursuant to the terms of this Agreement.
The General Partner,  in its sole discretion,  may elect to assign its rights to
purchase  the  Partnership  Interest  of the  Limited  Partner  involved  in the
Domestic  Proceeding  under this  Article 18.4 to the  Partnership  and, in such
case,  the  Partnership  shall have the same rights as provided  for the General
Partner in this Article 18.4.

                  18.5 Divestiture  Option.  If state or federal  regulations or
laws are enacted or applied, or if any other legal developments occur, which, in
the opinion of the General Partner  adversely  affect (or potentially  adversely
affect) the operation of the Partnership  (e.g., the enactment or application of
prohibitory physician  self-referral  legislation against the Partnership or its
Partners),  the General Partner shall promptly  either,  in its sole discretion,
(i) take the steps outlined in this Article 18.5 to divest the Limited  Partners
of their Partnership Interests,  or (ii) dissolve the Partnership as provided in
Article  24.1(e).  If the General Partner chooses option (i), it shall deliver a
written  notice to all of the Limited  Partners (the "Notice of  Election")  and
purchase such Partnership  Interests for its own account.  The purchase price to
be paid for each  Partnership  Interest  shall be  determined  in the  manner as
provided in Article 18.7 and shall be on the terms and conditions as provided in
Article  18.8.  The transfer of the  Partnership  Interests,  the payment of the
purchase price and the  assumption of the Limited  Partners'  obligations  under
their respective  Guaranties (as provided in Article 18.7) shall be made at such
time as  determined  by the General  Partner to be in the best  interests of the
Partnership  and its  Limited  Partners.  Each  Limited  Partner  hereby  makes,
constitutes and appoints the General  Partner,  with full power of substitution,
his true and lawful  attorney-in-fact,  to take such  actions and  execute  such
documents  on his behalf to effect the transfer of his  Partnership  Interest as
provided in this Article  18.5.  The  foregoing  power of attorney  shall not be
affected by the  subsequent  incapacity,  mental  incompetence,  dissolution  or
bankruptcy of any Limited Partner.

                                                       -20-

<PAGE>

                  18.6  Default  under  Guaranties.  Notwithstanding  any  other
provision in this Article 18 to the contrary,  if any of the events  outlined in
Articles  18.1 or 18.2 or any other  defaulting  event  outlined in the Guaranty
(the  "Defaulting  Events")  should occur with respect to a Limited Partner (the
"Defaulting  Limited Partner"),  and the General Partner determines (in its sole
discretion)  that  such  event may  result in  default  and  acceleration  of an
obligation  secured by the Guaranty unless another  guarantor  acceptable to the
Lender can be substituted in the place of the Defaulting  Limited Partner,  then
the  General  Partner  shall  have the  right to  immediately  take the steps as
outlined in this Article 18.6 to prevent such default.  Upon the General Partner
receiving  notice of a Defaulting  Event as provided above, the General Partner,
in its sole discretion,  shall immediately have the right to either (i) sell the
entire  Partnership  Interest of the Defaulting  Limited  Partner to an investor
approved of by the General Partner, (ii) purchase for its own account the entire
Partnership Interest of the Defaulting Limited Partner, or (iii) sell the entire
Partnership  Interest of the  Defaulting  Limited  Partner to one or more of the
other Limited  Partners.  The Defaulting  Limited  Partner shall sell his or her
Partnership  Interest to the purchaser at the purchase  price  determined in the
manner as provided in Article 18.7 and on the terms and  conditions  as provided
in Article 18.8. The transfer of the  Partnership  Interest,  the payment of the
purchase  price,  and  the  assumption  of  the  Defaulting   Limited  Partner's
obligations  under his or her Guaranty (as provided in Article  18.7),  shall be
made at such time as  determined  by the  General  Partner in order to avoid the
default and acceleration of the obligation secured by the Guaranty. Each Limited
Partner hereby makes,  constitutes and appoints the General  Partner,  with full
power of substitution, his or her true and lawful attorney-in-fact, to take such
actions and execute  such  documents on his or her behalf to effect the transfer
of his or her  Partnership  Interest as provided in this  Article  18.6,  in the
event such Limited Partner becomes a Defaulting Limited Partner.

                  18.7  Purchase  Price.  The purchase  price to be paid for the
Partnership  Interest of any Limited  Partner whose interest is being  purchased
pursuant to the provisions of Articles 18.1, 18.2, 18.3, 18.4, 18.5 or 18.6 (the
"Selling  Limited  Partner")  shall be determined in the manner provided in this
Article 18.7. The purchase price for a Partnership  Interest  purchased pursuant
to the provisions of Article 18.1 shall be an amount equal to the greater of (i)
one and one-half  (1.5) times the aggregate  distributions  made with respect to
such  Partnership  Interest  pursuant to Article  14(a) during the  twelve-month
period  ending on the  Valuation  Date (as defined  below),  or (ii) the Selling
Limited Partner's share of the Partnership's book value determined in the manner
described  below.  The  purchase  price  for a  Partnership  Interest  purchased
pursuant to the provisions of Articles 18.2,  18.3,  18.4, 18.5 or 18.6 shall be
an  amount  equal to the  lesser  of (i) the fair  market  value of the  Selling
Limited  Partner's  Partnership  Interest on the Valuation Date (prorated in the
event that only a portion of his or her Partnership Interest is being purchased)
as  determined  by an  Appraiser  (as  defined  below)  selected  by the General
Partner,  or (ii) the Selling Limited Partner's share of the Partnership's  book
value,  if any  (prorated  in  the  event  that  only  a  portion  of his or her
Partnership  Interest is being purchased) as reflected by the Capital Account of
the Selling  Limited  Partner  (unadjusted  for any  appreciation in Partnership
assets and as reduced by depreciation  deductions claimed by the Partnership for
tax purposes) as of the Valuation Date (as defined below).  The General Partner,
in its sole  discretion,  may pursue  both of the above  valuation  methods  and
choose the lesser  value of the two as indicated  above,  or may  designate  and
follow only one of the methods in calculating the purchase  price.  For purposes
of this Article 18.7, the term "Appraiser" shall mean

                                                       -21-

<PAGE>

an  independent  appraiser  who is qualified in appraising  limited  partnership
interests and who has at least five years experience. In determining fair market
value, the Appraiser shall take into consideration any outstanding indebtedness,
liabilities,   liens  and  obligations  of  the  Partnership  and  the  relative
Partnership  Interests and capital accounts of all Partners, as well as applying
any customary discounts for lack of liquidity and control.  Such appraisal shall
be conducted in accordance with professional appraisal standards.  The valuation
of the  Appraiser  shall be  conclusive  and binding upon the  Partnership,  the
purchaser and the Selling  Limited Partner and his or her  representatives.  The
determination  of the Selling  Limited  Partner's  Capital  Account or aggregate
distributable  amount on the Valuation  Date (as defined below) shall be made by
the  Partnership's  internal  accountant (the  "Partnership  Accountant") upon a
review of the  Partnership  books of account,  and a formal  audit is  expressly
waived. The statement of the Partnership  Accountant with respect to the Capital
Account or aggregate  distributable amount of the Selling Limited Partner on the
Valuation  Date  shall be  binding  and  conclusive  upon the  Partnership,  the
purchaser and the Selling  Limited Partner and his or her  representatives.  The
Valuation Date means the last day of the month  immediately  preceding the month
in which occurs:  (i) the death of a Selling Limited  Partner,  in the case of a
purchase by reason of death;  (ii) the  bankruptcy  or  insolvency  of a Selling
Limited  Partner,  in the case of a  purchase  by reason of such  bankruptcy  or
insolvency; (iii) the Notice of Withdrawal or breach of Article 15.3 as provided
in  Article  18.3  in the  case  of a  purchase  by  reason  thereof;  (iv)  the
commencement  of the  Domestic  Proceeding,  in the case of a purchase by reason
thereof;  (v) the Notice of Election as provided in Article 18.5, in the case of
a purchase by reason thereof; or (vi) the notice of Defaulting Event as provided
in Article  18.6,  in the case of a purchase  occurring by reason of one of such
events. Any Limited Partner whose Partnership  Interest is purchased pursuant to
the provisions of Article 18.1, 18.2, 18.3, 18.4, 18.5 or 18.6 shall be entitled
only to the  purchase  price  which  shall be paid at the Closing in cash (or by
certified  or  cashier's  check) and shall not be  entitled  to any  Partnership
distributions  made after the  Valuation  Date. If as of the date of the Closing
the Selling Limited Partner still has an outstanding  personal  obligation under
the Guaranty (the  "Obligation"),  the purchaser shall assume the portion of the
Obligation  as is  equal  to the  portion  of  the  Partnership  Interest  being
purchased,  indemnify  the  Selling  Limited  Partner  from such  portion of the
Obligation,  and take such steps  deemed  necessary  by the  General  Partner to
formally  evidence the assumption of such portion of the  Obligation,  including
without  limitation,  executing  such  documents  and providing  such  financial
information  to the Bank to  evidence  the  assumption  of such  portion  of the
Obligation,  and obtain if possible,  the release of the Selling Limited Partner
from such portion of the Obligation. The transfer of a Partnership Interest of a
Selling  Limited  Partner shall be deemed to occur as of the Valuation  Date and
the Selling  Limited  Partner  shall have no voting or other rights as a Limited
Partner after such date.  The purchaser  shall be entitled to any  distributions
attributable  to the  transferred  interest  after  the  Valuation  Date and the
Partnership shall have the right to deduct the amount of any such  distributions
made to the Selling  Limited  Partner after the Valuation Date from the purchase
price.  Notwithstanding  the above,  the  Partnership  shall not be obligated to
assume any outstanding personal obligation of a Selling Limited Partner.

                                                       -22-

<PAGE>

                  18.8     Closing.
                           -------

                  18.8.1  Closing  of  Purchase  and Sale.  The  Closing  of any
         purchase and sale of a Partnership  Interest  pursuant to Article 18.1,
         18.2,  18.3,  18.4 or 18.5 of this  Agreement  shall  take place at the
         principal office of the Partnership,  or such other place designated by
         the General Partner, on the date determined as follows (the "Closing"):

                  (a) In the case of a purchase and sale  occurring by reason of
         the death of a Limited  Partner as  provided  in  Article  18.1 of this
         Agreement,  the Closing  shall be held on the thirtieth day (or if such
         thirtieth  day is not a business  day, the next  business day following
         the thirtieth day) next following the last to occur of:

                         (i)   Qualification   of  the   executor   or  personal
                    administrator of the deceased Limited Partner's estate;

                         (ii) The date on which any necessary  determination  of
                    the  purchase  price  of  the  Partnership  Interest  to  be
                    purchased has been made; or

                         (iii)  The date  that  coincides  with the close of the
                    Option Period.

                  (b) In the case of a purchase and sale  occurring by reason of
         the  occurrence of one of the events  described in Article 18.2,  18.3,
         18.4 or  18.5  of this  Agreement,  the  Closing  shall  be held on the
         thirtieth day (or if such thirtieth day is not a business day, the next
         business day following the thirtieth  day) next  following the later to
         occur of:

                         (i) The date on which any  necessary  determination  of
                    the  purchase  price  of  the  Partnership  Interest  to  be
                    purchased has been made; or

                         (ii)  The date  that  coincides  with the  close of the
                    Option Period.

         At the Closing,  although not  necessary  to effect the  transfer,  the
         Selling Limited Partner shall  concurrently  with tender and receipt of
         the applicable  purchase price,  deliver to the purchaser duly executed
         instruments of transfer and  assignment,  assigning good and marketable
         title to the  portion or  portions  of the  Selling  Limited  Partner's
         entire  Partnership  Interest thus  purchased,  free and clear from any
         liens  or  encumbrances  or  rights  of  others  therein.  The  parties
         acknowledge  that occurrence of any of the triggering  events described
         in Article 18.1, 18.2, 18.3, 18.4, 18.5 or 18.6

                                                       -23-

<PAGE>

         and  compliance  with all the  Articles of this  Agreement,  except the
         execution of the transfer  documents by the Selling  Limited Partner as
         provided  above in this Article  18.8.1,  are  sufficient to effect the
         complete transfer of the Selling Limited Partner's Partnership Interest
         and the Selling Limited Partner shall be deemed to consent to admission
         of the transferee as a substitute Limited Partner.  Notwithstanding the
         date of the  Closing  or whether a Closing is  successfully  held,  the
         transfer of a Partnership  Interest of a Selling  Limited Partner shall
         be deemed to occur as of the Valuation Date as defined in Article 18.7.
         The deemed  transfer  is  effective  regardless  of whether the Selling
         Limited Partner performs the duties set forth in this Article 18.8.1.

                  18.8.2  Terms and  Conditions  of  Purchase.  The  Partnership
         Interest of a Limited  Partner shall not be  transferred to any Partner
         unless the  requirements  of Articles 17.2 and 17.4 (b) through (f) are
         satisfied  with  respect to it. The  purchaser  shall be liable for all
         obligations  and  liabilities   connected  with  that  portion  of  the
         Partnership  Interest  transferred  to it  unless  otherwise  agreed in
         writing.

                  19.      SALE, ASSIGNMENT OR OTHER TRANSFER OF THE GENERAL
                           -------------------------------------------------
                           PARTNER'S INTEREST.
                           ------------------

                  19.1  The   General   Partner   may  not   mortgage,   pledge,
hypothecate,  transfer,  sell, assign or otherwise dispose of all or any part of
its interest in the  Partnership,  whether  voluntarily,  by operation of law or
otherwise (the foregoing  actions being  hereafter  collectively  referred to as
"Transfers" or singularly as a "Transfer") except as permitted by this Article.

                  19.2 If the  General  Partner  makes a Transfer  (other than a
mortgage,  pledge or  hypothecation)  of its  general  partner  interest  in the
Partnership pursuant to this Article, it shall be liable for all obligations and
liabilities  incurred  by it as the  general  partner of the  Partnership  on or
before  the  effective  date of such  Transfer,  but shall not be liable for any
obligations or liabilities of the  Partnership  arising after the effective date
of the Transfer.

          19.3 No Transfer by the General Partner shall be permitted unless:

                  (a) Counsel for the Partnership shall have rendered an opinion
         that none of the actions  taken in  connection  with such Transfer will
         cause the Partnership to be classified  other than as a partnership for
         federal   income  tax  purposes  or  will  cause  the   termination  or
         dissolution of the Partnership under state law; and

                  (b) Such  documents  or  instruments,  in form  and  substance
         satisfactory to counsel for the  Partnership,  shall have been executed
         and  delivered  as may be  required  in the  opinion of counsel for the
         Partnership to effect fully any such Transfer.

                                                       -24-

<PAGE>

                  Notwithstanding the foregoing provisions of this Article 19.3,
the General  Partner may pledge its  interest  in the  Partnership  to any bank,
insurance   company  or  other  financial   institution  to  secure  payment  of
indebtedness.

                  20.      TERMINATION OF THE SERVICES OF THE GENERAL PARTNER.
                           --------------------------------------------------

                  If the General Partner shall be finally adjudged by a court of
competent  jurisdiction to be liable to the Limited  Partners or the Partnership
for any act of gross negligence or willful  misconduct in the performance of its
duties under the terms of this Agreement, the General Partner may be removed and
another  substituted  with the  consent  of all of the  Limited  Partners.  Such
consent  shall be evidenced  by a  certificate  of removal  signed by all of the
Limited Partners. In the event of removal, the new general partner shall succeed
to all of the powers, privileges and obligations of the General Partner, and the
General  Partner's  interest in the  Partnership  shall become that of a Limited
Partner,  and the General Partner shall maintain its same Percentage Interest in
the Partnership  notwithstanding  anything contained in the Act to the contrary.
In addition,  in the event of removal,  the new general  partner  shall take all
steps  necessary  and  appropriate  to prepare  and record an  amendment  to the
Certificate of Limited Partnership to reflect the removal of the General Partner
and the admission of such new general partner.

                  21.      MANAGEMENT AND OPERATION OF BUSINESS.
                           ------------------------------------

                  21.1 All  decisions  with  respect  to the  management  of the
business and affairs of the Partnership shall be made by the General Partner.

                  21.2 The General  Partner shall be under no duty to devote all
of its time to the business of the Partnership,  but shall devote only such time
as it deems  necessary  to conduct the  Partnership  business and to operate and
manage the Partnership in an efficient manner.

                  21.3 The  General  Partner may charge to the  Partnership  all
ordinary and necessary costs and expenses, direct and indirect,  attributable to
the activities,  conduct and management of the business of the Partnership.  The
costs and expenses to be borne by the  Partnership  shall  include,  but are not
limited to, all  expenditures  incurred in acquiring and financing the Equipment
or other Partnership property, legal and accounting fees and expenses,  salaries
of employees of the Partnership,  consulting and quality  assurance fees paid to
independent contractors, insurance premiums and interest.

                  21.4 In addition to, and not in limitation  of, any rights and
powers  covenanted by law or other  provisions of this Agreement,  and except as
limited,  restricted or prohibited by the express  provisions of this Agreement,
the General Partner shall have and may exercise on behalf of the Partnership all
powers and rights necessary,  proper,  convenient or advisable to effectuate and
carry out the purposes, business and objectives of the Partnership.  Such powers
shall include, without limitation, the following:

                                                       -25-

<PAGE>

               (a) To conduct the Offering  and any Dilution  Offering on behalf
          of the Partnership;

                  (b) To  acquire on behalf of the  Partnership  (i) one or more
         fixed  base  or  transportable   lithotripsy  systems,   including  the
         Lithotripter  System, (ii) any other assets related to the provision of
         lithotripsy  services,  or (iii) any other  assets or  equipment  or an
         interest  in  another  entity  consistent  with  the  purposes  of  the
         Partnership  as provided in Article 4  (collectively,  the  "Additional
         Assets"),  at such times and at such price and upon such terms,  as the
         General Partner deems to be in the best interest of the Partnership;

                  (c) To purchase,  hold, manage,  lease, license and dispose of
         Partnership assets, including the purchase,  exchange, trade or sale of
         the Partnership's assets at such price, or amount, for cash, securities
         or other property and upon such terms,  as the General Partner deems to
         be in the best interest of the Partnership;  provided,  that should the
         Partnership  assets be  exchanged  or traded  for  securities  or other
         property (the  "Replacement  Property") the General  Partner shall have
         the same  powers  with  regard to the  Replacement  Property as it does
         towards the traded property;

               (d)  To  exercise  the  option  of  the  General  Partner  or the
          Partnership  to  purchase  a Limited  Partner's  Partnership  Interest
          pursuant to Article 18;

               (e) To determine the travel  itinerary and site locations for the
          Lithotripter System or other Partnership technology;

                  (f) To borrow money for any Partnership purpose (including the
         acquisition  of the  Additional  Assets)  and,  if security is required
         therefor, to subject to any security device any portion of the property
         for the  Partnership,  to obtain  replacements  of any  other  security
         device, to prepay, in whole or in part,  refinance,  increase,  modify,
         consolidate or extend any encumbrance or other security device;

                  (g) To deposit,  withdraw,  invest, pay, retain (including the
         establishment  of reserves in order to acquire the  Additional  Assets)
         and distribute the  Partnership's  funds in any manner  consistent with
         the provisions of this Agreement;

                  (h)      To institute and defend actions at law or in equity;

                  (i) To enter into and carry out contracts and  agreements  and
         any or all documents and  instruments  and to do any and all such other
         things as may be in furtherance of Partnership purposes or necessary or
         appropriate to the conduct of the Partnership activities;

                                                       -26-

<PAGE>

               (j) To execute,  acknowledge  and deliver any and all instruments
          which may be deemed necessary or convenient to effect the foregoing;

                  (k) To engage or retain one or more persons to perform acts or
         provide  materials  as  may be  required  by  the  Partnership,  at the
         Partnership's  expense,  and to compensate  such person or persons at a
         rate to be set by the General  Partner,  provided that the compensation
         is at the then  prevailing  rate for the type of services and materials
         provided,  or both.  Any person,  whether a Partner,  an Affiliate of a
         Partner or otherwise, including without limitation the General Partner,
         may be employed or engaged by the  Partnership  to render  services and
         provide materials,  including, but not limited to, management services,
         professional   services,   accounting   services,   quality  assessment
         services, legal services,  marketing services,  maintenance services or
         provide materials; and if such person is a Partner or an Affiliate of a
         Partner, (s)he shall be entitled to, and shall be paid compensation for
         said services or materials,  anything in this Agreement to the contrary
         notwithstanding, provided that the compensation to be received for such
         services  or  materials  is  competitive  in price and terms  with then
         prevailing rate for the type of services and/or materials provided. The
         Partnership,  pursuant  to the terms of a  Management  Agreement,  will
         contract with Sun Medical Technologies,  Inc., a California corporation
         ("Sun") and the general partner of the General Partner, with respect to
         the supervision and  coordination of the management and  administration
         of the  day-to-day  operations  of  the  Partnership's  business  for a
         monthly fee equal to 7.5% of net Partnership  Cash Flow per month.  All
         costs incurred by Sun under the Management  Agreement  shall be paid or
         reimbursed  by the  Partnership  directly.  The  Partnership  may  also
         contract  with  healthcare   facilities  and/or  qualified   physicians
         desiring to use its Lithotripter  System for the treatment of patients.
         Owning an interest in the Partnership shall not be a condition to using
         the  Lithotripter  System.  The  General  Partner  and  its  Affiliates
         (including  Sun) may engage in or possess an interest in other business
         ventures of any nature and  description  independently  or with others,
         including,  but not limited to, the operation of a fixed-base or mobile
         lithotripsy  unit,  whether or not such business ventures are in direct
         or  indirect   competition  with  the  Partnership,   and  neither  the
         Partnership  nor the  Partners  shall  have any right by virtue of this
         Agreement  in and to said  independent  ventures  or to the  income  or
         profits derived therefrom.

                  21.5  In  addition  to  other  acts  expressly  prohibited  or
restricted  by this  Agreement  or by law,  the  General  Partner  shall have no
authority to act on behalf of the Partnership in:

                    (a) Doing any act in  contravention of this Agreement or the
               Partnership's Certificate of Limited Partnership;

                    (b) Doing any act which would make it impossible to carry on
               the ordinary business of the Partnership;

                                                       -27-

<PAGE>

                    (c)   Possessing   or  in  any  manner   dealing   with  the
               Partnership's property or assigning the rights of the Partnership
               in  the   Partnership's   property  for  other  than  Partnership
               purposes;

                    (d)  Admitting  a person as a Limited  Partner  or a General
               Partner except as provided in this Agreement; or

                  (e)  Performing  any act (other  than an act  required by this
         Agreement  or any act  taken  in good  faith  reliance  upon  counsel's
         opinion)  which  would,  at the time  such act  occurred,  subject  any
         Limited Partner to liability as a general partner in any jurisdiction.

                  22.      RESERVES.

                  The  General  Partner  may cause the  Partnership  to create a
reserve account to be used exclusively for repairs and acquisition of Additional
Assets and for any other valid Partnership  purpose.  The General Partner shall,
in its sole discretion, determine the amount of payments to such reserve.

                  23.      INDEMNIFICATION AND EXCULPATION OF THE GENERAL
                           PARTNER.

                  23.1 The General  Partner is accountable to the Partnership as
a fiduciary and consequently  must exercise good faith and integrity in handling
Partnership  affairs.  The  General  Partner  and its  Affiliates  shall have no
liability to the  Partnership  which arises out of any action or inaction of the
General Partner or its Affiliates if the General  Partner or its Affiliates,  in
good faith,  determined  that such course of conduct was in the best interest of
the Partnership and such course of conduct did not constitute  gross  negligence
or willful  misconduct  of the General  Partner or its  Affiliates.  The General
Partner and its Affiliates  shall be indemnified by the Partnership  against any
losses, judgments,  liabilities,  expenses and amounts paid in settlement of any
claims sustained by them in connection with the  Partnership,  provided that the
same were not the result of gross  negligence or willful  misconduct on the part
of the General Partner or its Affiliates.

                  23.2 The General Partner shall not be liable for the return of
the Capital Contributions of the Limited Partners, and upon dissolution, Limited
Partners shall look solely to the assets of the Partnership.

                  24.      DISSOLUTION OF THE PARTNERSHIP.

     24.1 The  Partnership  shall be dissolved and  terminated  and its business
wound up upon the occurrence of any one of the following events:

                  (a)      The expiration of its term on December 31, 2049;

                                                       -28-

<PAGE>

                  (b) The  filing  by, on  behalf  of, or  against  the  General
         Partner of any  petition or  pleading,  voluntary  or  involuntary,  to
         declare the General  Partner  bankrupt under any bankruptcy law or act,
         or the  commencement  in any  court  of any  proceeding,  voluntary  or
         involuntary,  to declare the General Partner insolvent or unable to pay
         its debts, or the appointment by any court or supervisory  authority of
         a  receiver,  trustee or other  custodian  of the  property,  assets or
         business of the General  Partner or the  assignment by it of all or any
         part of its  property or assets for the benefit of  creditors,  if said
         action,  proceeding  or  appointment  is  not  dismissed,   vacated  or
         otherwise terminated within ninety (90) days of its commencement;

               (c) The determination of the General Partner that the Partnership
          should be dissolved;

                  (d) The occurrence of an event described in a plan approved by
         the General Partner and a Majority in Interest of the Limited  Partners
         pursuant  to  Article  17.7   resulting  in  the   dissolution  of  the
         Partnership;

               (e)  The  election  of  the  General   Partner  to  dissolve  the
          Partnership  following the occurrence of an event described in Article
          18.5;

                  (f) Except as otherwise  provided in any plan  approved by the
         General  Partner and a Majority  in  Interest  of the Limited  Partners
         pursuant to Article 17.7,  the sale,  exchange or other  disposition of
         all or  substantially  all of the property of the  Partnership  without
         making provision for the replacement thereof;

                  (g)   The   dissolution,   retirement,   resignation,   death,
         disability  or legal  incapacity  of a general  partner,  and any other
         event  resulting in the  dissolution or termination of the  Partnership
         under the laws of the State of  California;  provided,  that the events
         described  in  Sections  15681(c)  and  (d) of the  Act or any  similar
         provisions of any successor  statute,  shall not work a dissolution  of
         the Partnership except as expressly provided in (b) above;

               (h) The election to dissolve the  Partnership  made by all of the
          Partners.

                  24.2  Notwithstanding  the  provisions  of Article  24.1,  the
Partnership   shall  not  be  dissolved  and  terminated  upon  the  retirement,
resignation,  bankruptcy,  assignment for the benefit of creditors, dissolution,
death,  disability or legal  incapacity of a general  partner,  and its business
shall continue  pursuant to the terms and conditions of this  Agreement,  if any
general partner or general partners remain  following such event;  provided that
such  remaining  general  partner or general  partners  are hereby  obligated to
continue the business of the  Partnership.  If no general  partner remains after
the  occurrence of such event,  the business of the  Partnership  shall continue
pursuant to the terms and conditions of this  Agreement,  if, within ninety (90)
days after the occurrence of such

                                                       -29-

<PAGE>

event,  a Majority  in  Interest  of the  Limited  Partners  agree in writing to
continue the business of the Partnership,  and, if necessary, to the appointment
of one or more persons or entities to be substituted as the general partner.  In
the event the Limited  Partners agree as provided above to continue the business
of the Partnership, the new general partner or general partners shall succeed to
all of the powers,  privileges and obligations of the General  Partner,  and the
General  Partner's  interest in the Partnership shall become a Limited Partner's
interest hereunder. Furthermore, in the event a remaining general partner or the
Limited  Partners,  as the case may be,  agree to continue  the  business of the
Partnership  as provided  herein,  the  remaining  general  partner or the newly
appointed  general partner or general  partners,  as the case may be, shall take
all steps  necessary and  appropriate  to prepare and record an amendment to the
Certificate of Limited  Partnership to reflect the  continuation of the business
of the  Partnership  and the  admission  of a new  general  partner  or  general
partners, if any.

                  25.      DISTRIBUTION UPON DISSOLUTION.

                  Upon the dissolution and termination of the  Partnership,  the
General Partner or, if there is none, a representative  of the Limited Partners,
shall  cause  the  cancellation  of the  Partnership's  Certificate  of  Limited
Partnership,  shall liquidate the assets of the Partnership, and shall apply and
distribute the proceeds of such liquidation in the following order of priority:

               (a) First,  to the  payment of the debts and  liabilities  of the
          Partnership, and the expenses of liquidation;

                  (b) Second,  to the creation of any reserves which the General
         Partner  (or such  representatives  of the Limited  Partners)  may deem
         reasonably  necessary  for the payment of any  contingent or unforeseen
         liabilities or obligations of the Partnership or of the General Partner
         arising out of or in connection  with the business and operation of the
         Partnership; and

                  (c) Third,  the balance,  if any,  shall be distributed to the
         Partners in accordance  with the  Partners'  positive  Capital  Account
         balances  after such  Capital  Accounts  are  adjusted  as  provided by
         Article 13, and any other  adjustments  required by the Final  Treasury
         Regulations  under Section 704(b) of the Code. Any general partner with
         a negative  Capital Account  following the  distribution of liquidation
         proceeds or the  liquidation  of its interest  must  contribute  to the
         Partnership  an amount  equal to such  negative  Capital  Account on or
         before the end of the Partnership's  taxable year (or, if later, within
         ninety days after the date of liquidation).  Any capital so contributed
         shall  be (i)  distributed  to those  Partners  with  positive  Capital
         Accounts until such Capital  Accounts are reduced to zero,  and/or (ii)
         used to discharge recourse liabilities.

                                                       -30-

<PAGE>

                  26.      BOOKS OF ACCOUNT, RECORDS AND REPORTS.

                  26.1 Proper and complete records and books of account shall be
kept by the General  Partner in which shall be entered fully and  accurately all
transactions  and such other matters relating to the  Partnership's  business as
are usually  entered  into  records and books of account  maintained  by persons
engaged  in  businesses  of a like  character.  The  books  and  records  of the
Partnership  shall be prepared  according to the accounting method determined by
the General Partner.  The Partnership's  fiscal year shall be the calendar year.
The books and  records  shall at all times be  maintained  at the  Partnership's
Records Office and shall be open to the reasonable inspection and examination of
the Partners or their duly authorized representatives during reasonable business
hours.

                  26.2 Within  ninety (90) days after the end of each Year,  the
General  Partner shall send to each person who was a Limited Partner at any time
during such year such tax information,  including,  without limitation,  Federal
tax Schedule K-1, as shall be reasonably  necessary for the  preparation by such
person of his federal  income tax return.  The  General  Partner  will also make
available to the Limited Partners any other information required by the Act.

                  26.3 The General  Partner shall maintain at the  Partnership's
Records  Office  copies of the  Partnership's  original  Certificate  of Limited
Partnership   and  any  certificate  of  amendment,   restated   certificate  or
certificate of cancellation with respect thereto and such other documents as the
Act shall require.  The General Partner will furnish to any Limited Partner upon
request or as  otherwise  required by law a copy of the  Partnership's  original
Certificate of Limited  Partnership and any  certificate of amendment,  restated
certificate, or certificate of cancellation, if any.

                  26.4 The General Partner shall, in its sole  discretion,  make
for the  Partnership  any and all  elections  for  federal,  state and local tax
purposes including, without limitation, any election, if permitted by applicable
law, to adjust the basis of the Partnership's property pursuant to Code Sections
754,  734(b) and  743(b),  or  comparable  provisions  of state or local law, in
connection  with  transfers  of  interests in the  Partnership  and  Partnership
Distributions.

                  26.5 The  General  Partner is  designated  as the Tax  Matters
Partner  (as  defined  in  Section  6231 of the Code) and to act in any  similar
capacity  under  state or local law,  and is  authorized  (at the  Partnership's
expense):   (i)  to  represent  the   Partnership  and  Partners  before  taxing
authorities  or courts of competent  jurisdiction  in tax matters  affecting the
Partnership  or  Partners  in their  capacity  as  Partners;  (ii) to extend the
statute of limitations for assessment of tax deficiencies  against Partners with
respect to adjustments to the Partnership's federal, state or local tax returns;
(iii) to execute any agreements or other documents relating to or affecting such
tax matters, including agreements or other documents that bind the Partners with
respect to such tax matters or  otherwise  affect the rights of the  Partnership
and Partners; and (iv) to expend Partnership funds for professional services and
costs  associated  therewith.  The General Partner is authorized and required to
notify the federal,  state or local tax  authorities of the appointment of a Tax
Matters  Partner  in  the  manner  provided  in  Treasury   Regulations  Section
301.6231(a)(7)-1, as modified from time to time. In its

                                                       -31-

<PAGE>

capacity  as  Tax  Matters  Partner,  the  General  Partner  shall  oversee  the
Partnership's  tax affairs in the manner which, in its best judgment,  is in the
interests of the Partners.

                  27.      NOTICES.

                  All notices under this Agreement shall be in writing and shall
be deemed to have been given when delivered  personally,  or mailed by certified
or registered mail, postage prepaid,  return receipt  requested.  Notices to the
General  Partner  shall be  delivered  at, or mailed to, its  principal  office.
Notices to the  Partnership  shall be delivered  at, or mailed to, its principal
office with a copy to each of its business offices.  Notice to a Limited Partner
shall be  delivered  to such  Limited  Partner,  or mailed  to the last  address
furnished  by him for such  purposes to the General  Partner.  Limited  Partners
shall give  notice of a change of address to the  General  Partner in the manner
provided in this Article.

                  28.      AMENDMENTS.

                  Subject to the  provisions  of Article 28, this  Agreement  is
subject to  amendment  only by  written  consent of the  General  Partner  and a
Majority in Interest of the Limited Partners;  provided, however, the consent of
the Limited Partners shall not be required if such amendments are ministerial in
nature and do not contravene the provisions of Article 29.  Further,  no Limited
Partner  consent shall be required to amend  Schedule A to reflect the admission
of  Partners  as  contemplated  by the  Offering,  any  Dilution  Offering or as
otherwise herein permitted.

                  29.      LIMITATIONS ON AMENDMENTS.
                           -------------------------

                  Notwithstanding  the provisions of Article 28, no amendment to
this Agreement shall:

                  (a)  Enlarge  the   obligations  of  any  Partner  under  this
         Agreement  or convert the  interest in the  Partnership  of any Limited
         Partner  into the  interest of a general  partner or modify the limited
         liability of any Limited Partner, without the consent of such Partner;

                  (b) Amend the  provisions  of Article 13, 14, 16 or 25 without
         the  approval of the General  Partner and a Majority in Interest of the
         Limited Partners;  provided,  however,  that the General Partner may at
         any time  amend  such  Articles  without  the  consent  of the  Limited
         Partners in order to permit the Partnership allocations to be sustained
         for federal  income tax  purposes,  but only if such  amendments do not
         materially  affect  adversely the rights and obligations of the Limited
         Partners, in which case such amendments may only be made as provided in
         this Article 29(b); or

               (c) Amend this Article 29 without the consent of all Partners.

                                                       -32-

<PAGE>

                  30.      MEETINGS, CONSENTS AND VOTING.
                           -----------------------------

                  30.1 A meeting of the  Partnership to consider any matter with
respect to which the  Partners  may vote as set forth in this  Agreement  may be
called  by the  General  Partner  or by  Limited  Partners  who hold  more  than
twenty-five  percent (25%) of the aggregate interests in the Partnership held by
all the Limited Partners.  Upon receipt of a notice requesting a meeting by such
Partner or Partners and stating the purpose of the meeting,  the General Partner
shall, within ten (10) days thereafter, give notice to the Partners of a meeting
of the  Partnership to be held at a time and place  generally  convenient to the
Limited  Partners on a date not earlier than fifteen (15) days after  receipt by
the  General  Partner of the  notice  requesting  a  meeting.  The notice of the
meeting shall set forth the time, date, location and purpose of the meeting.

     30.2 Any consent of a Partner  required by this  Agreement  may be given as
follows:

               (a) By a written  consent  given by the  consenting  Partner  and
          received by the General Partner at or prior to the doing of the act or
          thing for which the consent is solicited, or

                  (b) By the affirmative  vote by the consenting  Partner to the
         doing of the act or thing for which the  consent  is  solicited  at any
         meeting  called  pursuant to this Article to consider the doing of such
         act or thing.

                  30.3 When exercising voting rights expressly granted under the
Articles of this  Agreement,  each Partner shall have that number of votes as is
equal to the  Percentage  Interest  of such  Partner  at the  time of the  vote,
multiplied by 100.

                  31.      SUBMISSIONS TO THE LIMITED PARTNERS.
                           -----------------------------------

                  The General Partner shall give the Limited  Partners notice of
any proposal or other matter  required by any provision of this  Agreement or by
law to be submitted for consideration and approval of the Limited Partners. Such
notice shall include any  information  required by the relevant  provision or by
law.

                  32.      ADDITIONAL DOCUMENTS.
                           --------------------

                  Each  party  hereto  agrees to  execute  and  acknowledge  all
documents and writings which the General Partner may deem necessary or expedient
in the creation of this Partnership and the achievement of its purpose.

                  33.      SURVIVAL OF RIGHTS.
                           ------------------

                  Except as herein  otherwise  provided  to the  contrary,  this
Agreement  shall be binding upon and inure to the benefit of the parties hereto,
their successor and assigns.

                                                       -33-

<PAGE>

                  34.      INTERPRETATION AND GOVERNING LAW.
                           --------------------------------

                  When the  context  in which  words are used in this  Agreement
indicates  that such is the intent,  words in the singular  number shall include
the plural and vise versa; in addition,  the masculine  gender shall include the
feminine and neuter  counterparts.  The Article headings or titles and the table
of  contents  shall not define,  limit,  extend or  interpret  the scope of this
Agreement  or any  particular  Article.  This  Agreement  shall be governed  and
construed in accordance with the laws of the State of California  without giving
effect to the conflicts of laws provisions thereof.

                  35.      SEVERABILITY.
                           ------------

                  If any provision,  sentence,  phrase or word of this Agreement
or the application  thereof to any person or circumstance shall be held invalid,
the remainder of this Agreement, or the application of such provision, sentence,
phrase, or word to persons or circumstances,  other than those as to which it is
held invalid, shall not be affected thereby.

                  36.      AGREEMENT IN COUNTERPARTS.
                           -------------------------

                  This Agreement may be executed in several  counterparts,  each
of which shall be deemed an original,  but all of which shall constitute one and
the same  instrument.  In  addition,  this  Agreement  may contain more than one
counterpart  of the  signature  page and this  Agreement  may be executed by the
affixing of the  signatures  of each of the Partners to one of such  counterpart
signature  pages;  all of such signature  pages shall be read as though one, and
they  shall have the same  force and  effect as though  all of the  signers  had
signed a single signature page.

                  37.      THIRD PARTIES.
                           -------------

                  The agreements, covenants and representations contained herein
are for the benefit of the parties  hereto  inter se and are not for the benefit
of any  third  parties  including,  without  limitation,  any  creditors  of the
Partnership.

                  38.      POWER OF ATTORNEY.
                           -----------------

                  Each Limited  Partner hereby makes,  constitutes  and appoints
Stan Johnson and Cheryl  Williams,  severally,  with full power of substitution,
his true and lawful attorneys-in-fact,  for him and in his name, place and stead
and for his use and  benefit  to sign  and  acknowledge,  file and  record,  any
amendments  hereto among the Partners for the further  purpose of executing  and
filing on behalf of each Limited  Partner,  any and all  certificates of limited
partnership or other  documents  necessary to constitute  the  Partnership or to
effect the  continuation  of the  Partnership,  the admission or withdrawal of a
general partner or a limited partner,  the qualification of the Partnership in a
foreign  jurisdiction  (or  amendment to such  qualification),  the admission of
substitute   Limited   Partners  or  the   dissolution  or  termination  of  the
Partnership, provided such continuation,  admission, withdrawal,  qualification,
or  dissolution  and  termination  are in  accordance  with  the  terms  of this
Agreement.

                                                       -34-

<PAGE>

                  The foregoing power of attorney is a special power of attorney
coupled with an interest,  is  irrevocable  and shall  survive the death,  legal
incapacity,  dissolution  or  bankruptcy  of  each  Limited  Partner.  It may be
exercised by any one of said  attorneys  by listing all of the Limited  Partners
executing any instrument over the signature of the  attorney-in-fact  acting for
all of them.  The power of attorney  shall survive the delivery of an assignment
by a Limited  Partner of the whole or any portion of his Unit. In those cases in
which the assignee of, or the successor to, a Limited  Partner owning a Unit has
been approved by the Partners for admission to the  Partnership  as a substitute
Limited  Partner,  the power of attorney  shall  survive for the sole purpose of
enabling the General  Partner to execute,  acknowledge  and file any  instrument
necessary to effect such substitution.

                  This power of attorney shall not be affected by the subsequent
bankruptcy,  dissolution,  incapacity  or  mental  incompetence  of any  Limited
Partner.

                  39.      ARBITRATION.
                           -----------

                  Any  dispute  arising  out  of  or  in  connection  with  this
Agreement or the breach thereof shall be decided by arbitration in Austin, Texas
in  accordance  with  the then  effective  commercial  arbitration  rules of the
American  Arbitration  Association,  and judgment  thereof may be entered in any
court having jurisdiction thereof.

                  40.      CREDITORS.
                           ---------

                  None of the  provisions  of this  Agreement  shall  be for the
benefit of or enforceable by any creditors of the Partnership.

                                             [signature page follows]

                                                       -35-

<PAGE>

                  IN WITNESS  WHEREOF,  the parties have executed this Agreement
of Limited Partnership as of the day and year first above written.

                           GENERAL PARTNER:

                           MOBILE KIDNEY STONE CENTERS OF

                           CALIFORNIA, LTD., a California limited
                               partnership

                           By:      Sun Medical Technologies, Inc., a California
                                    Corporation and its sole general partner

                           By:  /s/ Stan Johnson
                           ---------------------
                                Stan Johnson
                                President

ATTEST:

/s/ Vincent Prendergast                                        [CORPORATE SEAL]
-----------------------
Secretary

                                  INITIAL LIMITED PARTNER:
                                  -----------------------

                                  /s/ Stan Johnson
                                  ----------------
                                  Stan Johnson

                                                       -36-

<PAGE>

STATE OF North Carolina

COUNTY OF Cumberland

     On this 31 day of March,  1999, before me, the undersigned Notary Public in
and for the County of Cumberland in the State of North Carolina, personally came
Stan  Johnson,  who,  being by me duly sworn,  said that he is  President of Sun
Medical  Technologies,  Inc.,  the sole general  partner of Mobile  Kidney Stone
Centers of  California,  Ltd.,  the sole general  partner of Mobile Kidney Stone
Centers  of  California  II,  L.P.,  that  the  seal  affixed  to the  foregoing
instrument in writing is the corporate  seal of the  corporation,  and that said
writing was signed, sworn to, and sealed by him in behalf of said corporation by
its authority duly given. And the said Stan Johnson,  further certified that the
facts set forth in said  writing are true and  correct,  and  acknowledged  said
instrument to be the act and deed of said corporation.

                  WITNESS my hand and notarial seal.

                                    /s/ Debra J. Scott
                                    ------------------
                                    Notary Public

My commission expires:
May 1, 1999

STATE OF North Carolina

COUNTY OF Cumberland

                  I, Debra J. Scott, a notary public in and for
the State and  County  set forth  above,  do hereby  certify  that Stan  Johnson
personally appeared before me this 31 day of March, 1999 and acknowledged
and swore to the due execution of the foregoing Limited Partnership Agreement in
his capacity as the initial limited partner.

                                    /s/ Debra J. Scott
                                    ------------------
                                    Notary Public

My commission expires:
May 1, 1999

                                                       -37-

<PAGE>

                           COUNTERPART SIGNATURE PAGE

                  By signing this  Counterpart  Signature  Page, the undersigned
acknowledges  his or  her  acceptance  of  that  certain  Agreement  of  Limited
Partnership  of Mobile Kidney Stone Centers of California  II, L.P.,  and his or
her intention to be legally bound thereby.

                  Dated this _________ day of ___________________, 1999.

                                    Signature

                                    Printed Name

STATE OF _______________                    )
                                            )
COUNTY OF _____________                     )

                  BEFORE ME, the undersigned  Notary Public in and for the State
and County set forth  above,  on the  _______ day of  __________________,  1999,
personally  appeared  ___________________,  and,  being by me first duly  sworn,
stated that (s)he  signed this  Counterpart  Signature  Page for the purpose set
forth above and that the statements contained therein are true.

                           Signature of Notary Public

                             Printed Name of Notary

My Commission Expires:

---------------------------
[SEAL]

                                                       -38-

<PAGE>

                                   SCHEDULE A
                        Schedule of Partnership Interests

               MOBILE KIDNEY STONE CENTERS OF CALIFORNIA II, L.P.
               --------------------------------------------------
           CONTRIBUTIONS OF CAPITAL TO THE PARTNERSHIP AND PERCENTAGE
           ----------------------------------------------------------
                                    INTERESTS

                                  Cash                               Percentage
                                Contribution      Guaranty(1)         Interest
                                ------------       --------          -----------
General Partner

Mobile Kidney Stone Centers
   Of California, Ltd. I

15195 National Avenue,
Suite 203
Los Gatos, CA 95032              $100,000.00      $194,850.00            40.0%
Limited Partners
Erik Birzgalis, M.D.
3637 Mission Avenue

Carmichael, CA 95608             $  9,750.00      $ 18,997.88             3.9%
Frederick Burrell, M.D.
3160 Folsom Boulevard
Sacramento, CA 95816             $  7,500.00      $ 14,613.75             3.0%
Capital Urology Medical Group, Inc.
2801 K Street, Suite 220
Sacramento, CA 95816             $  9,750.00      $ 18,997.88             3.9%
Jong Chen, M.D.
3941 J Street #366
Sacramento, CA 95819             $  7,500.00      $ 14,613.75             3.0%
David Couillard, M.D.
2801 K Street #205
Sacramento, CA 95816             $  9,750.00      $ 18,997.88             3.9%
Leonard Crawford, M.D.
2801 K Street #220
Sacramento, CA 95816             $  9,750.00      $ 18,997.88             3.9%
Kaushik DeSai, M.D.
1600 Creekside Drive, Suite 2700
Folsom, CA 95630                 $  9,750.00      $ 18,997.88             3.9%
Abdo Faddoul, M.D.
Two Medical Plaza #125
Roseville, CA 95661              $  7,500.00      $ 14,613.75             3.0%

                                                       -39-

<PAGE>

                                        Cash                          Percentage
Patricia Fone, M.D.
2 Medical Plaza #255
Roseville, CA 95661       $    9,750.00           $ 18,997.88               3.9%
Klumars Hekmat, M.D.
2801 K Street #220
Sacramento, CA 95816      $    9,750.00           $ 18,997.88               3.9%
William Hoch, M.D.
2020 Sutter Place #102
Davis, CA 95616           $    7,500.00           $ 14,613.75               3.0%
H. Setsup Masaki, M.D.
5252 Elvas Avenue
Sacramento, CA 95819      $    5,000.00           $  9,742.50               2.0%
Iraj Nabi, M.D.
3160 Folsom Boulevard

Sacramento, CA 95816      $    7,500.00           $ 14,613.75               3.0%
Brian Naftulin, M.D.
2801 K Street #220
Sacramento, CA 95816      $    5,000.00           $  9,742.50               2.0%
Peter Novick, M.D.
77 Scripps Drive #112
Sacramento, CA 95825      $    9,750.00           $ 18,997.88               3.9%
Gordon Quinones, M.D.
6401 Coyle Avenue, Suite 310
Carmichael, CA 95608      $    5,000.00           $  9,742.50               2.0%
Nicholas Simopoulos, M.D.
100 Fowler Way #5
Placerville, CA 95667     $    9,750.00           $ 18,997.88               3.9%
Robert Wright, M.D.
2801 K Street #205
Sacramento, CA 95816      $    9,750.00           $ 18,997.88               3.9%

TOTAL:                      $250,000.00           $487,125.00             100.0%

(1 )Represents the principal portion of each Partner's guaranty  obligation,  as
each Partner's  obligation under the Guaranty  includes not only principal,  but
also (as provided in the  Guaranty)  accrued and unpaid  interest,  late payment
penalties  and all  costs  incurred  by the  Bank in  collecting  any  defaulted
obligations.  The  principal  amount of the loan is up to $487,125.  The General
Partner will guarantee 40% of the Loan (up to a $194,850 principal  guaranty) as
provided in the Memorandum.  The Limited Partners will individually guarantee 1%
of the loan (up to a $4,871.25  principal  guaranty) for each unit  purchased as
provided in the Memorandum.

                                                       -40-

<PAGE>FOURTH AMENDMENT TO
                       AGREEMENT OF LIMITED PARTNERSHIP OF
              LOUISIANA LITHOTRIPSY INVESTMENT LIMITED PARTNERSHIP

                  THIS AMENDMENT, effective as of the 1st day of April, 1999, is
entered into by and among Lithotripters,  Inc., a North Carolina corporation and
the General Partner of Louisiana Lithotripsy  Investment Limited Partnership,  a
North Carolina limited partnership (the "Partnership"), and the Limited Partners
of the Partnership.

                                R E C I T A L S:
                                 ---------------

                  1. The General Partner and the Limited  Partners,  hereinafter
collectively  referred to as the  "Partners",  entered into that certain Amended
and  Restated  Agreement  of  Limited   Partnership  of  Louisiana   Lithotripsy
Investment Limited Partnership, dated as of October 30, 1989, as amended by that
certain First Amendment to Agreement of Limited  Partnership of the Partnership,
effective as of January 1, 1990, and as amended by that certain Second Amendment
to Agreement of Limited Partnership of the Partnership,  effective as of January
1, 1997, and as amended by that certain Third  Amendment to Agreement of Limited
Partnership of the Partnership,  effective as of July 1, 1998 (the  "Partnership
Agreement").

                  2. The  Partners  desire  to  further  amend  the  Partnership
Agreement to reflect the Partners's adjusted Percentage Interests resulting from
the  Partnership's  Dilution  Offering,  and  the  subsequent  admission  of the
following new Limited Partners to the Partnership; Christopher P. Fontenot, M.D.
(1.000%),  Gordon Sean Healey  (0.500%),  Brad Johnson  (1.000%),  Chuen K. Kwok
(1.000%),  Steven A. Socher  (1.000%),  Lance Templeton  (1.000%) and Kenneth S.
Verheeck (1.000%).

                  NOW,  THEREFORE,  in  consideration  of the  mutual  promises,
covenants,  conditions and agreements herein contained, the parties hereto agree
as follows:

                           Schedule  A-2 is  deleted in its  entirety  and a new
                           Schedule A-3,  attached hereto, is substituted in its
                           place.

                  IN WITNESS WHEREOF, the Partners have hereunto set their hands
and seals effective as of the date first above written.

                                                     GENERAL PARTNER:

                                                     Lithotripters, Inc.

                                                     By:/s/ Joseph Jenkins, M.D.
                                                     ---------------------------
                                                            Joseph Jenkins, M.D.
                                                            President

<PAGE>

                                                     ALL THE LIMITED PARTNERS OF
                                                     THE PARTNERSHIP WHOSE NAMES
                                                     APPEARED ON SCHEDULE A-3

                                                     By:/s/ Joseph Jenkins, M.D.
                                                     ---------------------------
                                                            Joseph Jenkins, M.D.
                                                            Attorney-in-Fact1
--------
     1            Pursuant to a Power of Attorney given by the Limited Partners.

                                                         2

<PAGE>

                                                                    SCHEDULE A-3

                        Schedule of Partnership Interests

              LOUISIANA LITHOTRIPSY INVESTMENT LIMITED PARTNERSHIP

            CONTRIBUTIONS OF CAPITAL TO THE PARTNERSHIP AND INTERESTS

                                 Cash Contribution(1)     Percentage Interest(2)
                                  -----------------        -------------------
General Partner

Lithotripters, Inc.                  $1,000.00                   1.165%
2008 Litho Place, Suite 201
Fayetteville, NC  28304
Limited Partners

Thomas Alderson, M.D.                $2,000.00                   2.281%
234 S. Ryan
Lake Charles, LA  70601
David Autin, M.D.                    $2,500.00                   2.853%
4212 W. Congress
Lafayette, LA  70503
Bruce Bass, M.D.                     $1,000.00                   1.136%
234 S. Ryan
Lake Charles, LA  70601
Al Beachum, M.D.                     $3,500.00                   3.989%
913 S. College Road
Lafayette, LA  70503
Maged R. Botros, M.D.                $2,500.00                   2.853%
Mary Dickerson Hospital
Jasper, TX  75951
J. Bourdreau, M.D.                   $1,000.00                   1.136%
4212 W. Congress
Lafayette, LA  70503
Charles Bowie, M.D.                  $1,000.00                   0.757%
4400 Moosa Blvd.
Eunice, LA  70535
Edward Breaux, M.D.                  $2,000.00                   2.281%
118 Hospital Drive
Lafayette, LA  70503

                                                         1

<PAGE>

                          Cash Contribution(1)            Percentage Interest(2)
Joseph Busby, M.D.              $2,500.00                        2.853%
2104-G Loop Road
Winnsboro, LA  71295
J. Michael Cage, M.D.           $2,500.00                        1.902%
711 St. John Street
Monroe, LA  71201
Gerardo Chica, M.D.             $2,000.00                        2.281%
1323 S. 27th, Suite 300
Nederland, TX  77627
Martin Ducote, M.D.             $3,500.00                        3.989%
604 St. Landry Street
Lafayette, LA  70506
Edwin Edgerton, M.D.            $1,000.00                        0.757%
2417 N. 7th Street
West Monroe, LA  71291
John Enright, M.D.              $2,000.00                        2.281%
234 S. Ryan
Lake Charles, LA  70601
Christopher P. Fontenot(3)     $32,028.00                        1.180%
Carroll Guinn, M.D.             $1,000.00                        1.136%
602 N. Lewis
New Iberia, LA  70560
James M. Harris, M.D.           $2,000.00                        2.281%
810 Hospital Drive
Beaumont, TX  77701
John Denton Harris, M.D.        $3,500.00                        3.989%
810 Hospital Drive
Beaumont, TX  77701
G. Bruce Healey, M.D.           $2,000.00                        2.281%
3020 Allison
Groves, TX  77619
Gordon Sean Healey(3)          $16,014.00                        0.590%
John Henderson, M.D.            $2,500.00                        2.853%
810 Hospital Drive
Beaumont, TX  77701

                                                         2

<PAGE>

                                  Cash Contribution(1)    Percentage Interest(2)
George Hoffman, M.D.                 $2,500.00                   2.853%
3212 Concord Dr., Suite F
Orange, TX  77630
Brad Johnson(3)                     $32,028.00                   1.180%
Thomas Jordan                          $281.25                   0.425%
233 W. Broadway, Suite 501
Louisville, KY  40202
Chuen K. Kwok(3)                    $32,028.00                   1.180%
Edmond Lamperez, M.D.                $1,000.00                   0.757%
602 N. Lewis
New Iberia, LA  70560
Arthur Liles, M.D.                   $2,500.00                   2.853%
711 St. John Street
Monroe, LA  71201
Lithotripters, Inc.(4)               $2,000.00                   8.467%
2008 Litho Place
Fayetteville, NC  28304
Leo Lowentritt, M.D.                 $2,500.00                   2.853%
3311 Prescott Road
Alexandria, LA  71301
Don F. Marx, M.D.                    $2,500.00                   2.853%
North Monroe Medical Plaza
Suite I
Monroe, LA  71203

Robert Marx, M.D.                    $2,000.00                   2.281%
417 Wood Street
Monroe, LA  71201
James Meek, M.D.                     $2,000.00                   1.523%
301 4th Street
Alexandria, LA  71301
Charles E. Moss, M.D.                $2,000.00                   2.281%
118 Hospital Drive
Lafayette, LA  70503
Seth Novoselsky, M.D.                $1,000.00                   1.136%
3311 Prescott Road
Suite 103
Alexandria, LA  71301

                                                         3

<PAGE>

                            Cash Contribution(1)          Percentage Interest(2)
Tika Ranjitkar, M.D.            $2,000.00                             2.281%
1200 S. Farmerville
Ruston, LA  71270
James Rounder, M.D.             $1,000.00                             1.136%
3311 Prescott Road
Suite 103
Alexandria, LA  71301
Manuel Soasai, M.D.             $2,500.00                             2.853%
710 S. 8th Street
Beaumont, TX  77701
Steven A. Socher(3)             $32,028.00                            1.180%
Benjamin Stage, M.D.             $2,500.00                            2.853%
612 S. Washington
Bastrop, PA  71220
Charles Tanner, M.D.             $1,000.00                            0.757%
1200 S. Farmerville
Ruston, LA  71270
Lane Templeton(3)               $32,028.00                            1.180%
Paul Tennis, M.D.                $2,500.00                            2.853%
711 St. John Street
Monroe, LA  71201
Richard Texada, M.D.             $1,000.00                            1.136%
3311 Prescott Road
Alexandria, LA  71301
Jack Thielen, M.D.               $1,000.00                            1.136%
234 S. Ryan
Lake Charles, LA  70601
Kenneth S. Verheeck(3)          $32,028.00                            1.180%
J.W. Vildibill, M.D.             $3,500.00                            3.989%
604 St. Landry Street
Lafayette, LA  70506
         TOTAL                  286,463.25                           100.00%

(1)      The cash contributions  reflect the initial cash contributions of those
         Partners who currently hold an interest in the Partnership.

(2)      Percentage figures are approximated.

                                                         4

<PAGE>

(3)      Limited partnership interest was acquired pursuant to the Partnership's
         dilution offering which closed March 31, 1999.

(4) Lithotripters,  Inc. acquired a portion of its percentage interests pursuant
to various assignments from limited partners of the Partnership  effective as of
January 1,  1997,  and made no cash  contributions  to the  Partnership  for the
limited partner interests received as a result of such assignments.

                                                         5

<PAGE>

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