SECOND AMENDMENT TO
                       AGREEMENT OF LIMITED PARTNERSHIP OF
                 TEXAS LITHOTRIPSY LIMITED PARTNERSHIP VII, L.P.


     THIS  AMENDMENT,  effective  as of the 1st day of January,  1999 is entered
into by and among  Lithotripters,  Inc., a North  Carolina  corporation  and the
General  Partner  of  Texas  Lithotripsy  Limited  Partnership  VII,  L.P.  (the
"Partnership"), and the Limited Partners of the Partnership.

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

                  1. The General  Partner and the Initial  Limited Partner named
therein  entered into that certain  Agreement  of Limited  Partnership  of Texas
Lithotripsy  Limited  Partnership  VII, L.P.,  dated as of September 4, 1998, as
amended by that certain  Amendment to  Agreement of Limited  Partnership  of the
Partnership, effective as of October 7, 1998 (the "Agreement").

                  2. The General  Partner and the undersigned  Limited  Partners
(collectively,  the "Partners") desire to further amend the Agreement to reflect
the successful  closing of the Merger pursuant to the Merger Agreement,  and the
assignment by William Mulchin,  M.D. of his .29893238%  limited partner interest
in the Partnership to Fifth Street Corp.

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

                           Schedule  A is  deleted  in  its  entirety  and a new
                           Schedule A-1,  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




                                                        -1-


<PAGE>





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

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



                                                        -2-


<PAGE>






                                                                    SCHEDULE A-1

                        Schedule of Partnership Interests

                 TEXAS LITHOTRIPSY LIMITED PARTNERSHIP VII, L.P.
                 -----------------------------------------------



General Partner                                        Percentage Interest
---------------                                        -------------------
Lithotripters, Inc.                                        20.80897806%
2008 Litho Place
Fayetteville, NC 28304
Limited Partners

Robert Admire                                               0.41200000%
Joyce Allen                                                 0.29893238%
Mark Allen                                                  0.20600000%
Thomas Arnold                                               1.15074320%
John Ballard, III                                           0.29893238%
Charles Bamberger                                           1.74054700%
Marc Barrett                                                2.30148640%
James Brady                                                 0.20600000%
Franklin Clark                                              0.20600000%
James Cochran                                               1.29537367%
Donald Cook                                                 0.29893238%
Stephen Corwin                                              0.29893238%
Philip Damstra                                              0.38375240%
Jules Delaune                                               0.57537160%
Ruth Delaune                                                0.57537160%
Robert Dowling                                              0.38375240%




                                                        -3-


<PAGE>





Limited Partners                                       Percentage Interest
----------------                                       -------------------
J. Stephen Dryden                                           0.20600000%
Richard Dulany                                              0.20600000%
Glenn Dunnington                                            0.29893238%
Christopher Fetner                                          0.82400000%
Fifth Street Corp                                           2.09252669%
Larry Frank                                                 0.20600000%
Gerald Frankel                                              0.82400000%
William Freeborn                                            0.82400000%
Alan Freeman                                                0.29893238%
Philip Gallina                                              0.20600000%
Glen Goldsmith                                              0.29893238%
William Grine                                               0.20600000%
Scott Hassell                                               0.41200000%
Wayne Hey                                                   0.76699080%
A. Mason Holden                                             0.29893238%
Ira Hollander                                               1.72611480%
Joseph Jenkins                                              0.20600000%
Dan Johnson                                                 1.43842900%
John Johnson                                                0.57537160%
Sid Jones                                                   1.15074320%
Lillian Jordan                                              0.57537160%
Thomas Jordan                                               0.20600000%
William Jordan                                              0.20600000%
T.S. Kent                                                   0.29893238%




                                                        -4-


<PAGE>





Farid Khoury                                                0.20600000%
Mario Labardini                                             0.20600000%
J.L. LaManna, III                                           0.29893238%
Hugh Lamensdorf                                             1.15074320%
Edward Lee                                                  1.15074320%
Stephen Lieman                                              0.61800000%
Lithotripters, Inc.                                        22.05669678%
Barney Maddox                                               0.29893238%
Donald McKay                                                0.61800000%
William Mitchell                                            0.29893238%
Thomas Mobley                                               0.20600000%
Yondell Moore                                               0.20600000%
Dan Myers                                                   0.20600000%
Jerry Newton                                                0.29893238%
Denis Ortiz                                                 0.38375240%
Paris Urology Assoc. Pension                                0.59786477%
Allen Plotkin                                               0.29893238%
Drew Pumphrey                                               1.53454700%
Anthony Rand                                                0.20600000%
Richard Reese                                               0.59786477%
Jack Rice                                                   0.29893238%
 Edward Rietze Estate                                       0.20600000%
William Risk                                                1.49466192%
Donald Ross                                                 0.57537160%




                                                        -5-


<PAGE>




James Saalfield                                             0.97299080%
Rashinda Singh                                              0.57537160%
Southwest Lithotripter Partners                             8.70117438%
John Staub                                                  0.29893238%
Martha Storrie                                              2.15254700%
Mark Story                                                  2.01380060%
Robert Stroud                                               0.38375240%
Roger Stuart                                                0.20600000%
Agif Syed                                                   0.29893238%
Alan Terry                                                  0.20600000%
Addison Thurman                                             1.15074320%
Arthur Tijerina                                             1.79359431%
Eugene Todd                                                 0.59786477%
Michael Walter                                              0.57537160%
R.D. West                                                   0.19928826%
Jeannie Westerburg                                          0.19928826%
Robert Westerburg                                           0.19928826%
Roger Wolfert                                               0.29893238%
                                                            -----------
TOTAL                                                         100%





                                                        -6-


<PAGE>


                               THIRD AMENDMENT TO
                       AGREEMENT OF LIMITED PARTNERSHIP OF
                 TEXAS LITHOTRIPSY LIMITED PARTNERSHIP VII, L.P.


     THIS  AMENDMENT,  effective as of the 2nd day of February,  1999 is entered
into by and among  Lithotripters,  Inc., a North  Carolina  corporation  and the
General  Partner  of  Texas  Lithotripsy  Limited  Partnership  VII,  L.P.  (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 Agreement
of Limited Partnership of Texas Lithotripsy Limited Partnership VII, L.P., dated
as of  September 4, 1998,  as amended by that certain  Amendment to Agreement of
Limited Partnership of the Partnership,  effective as of October 7, 1998, and as
further  amended  by that  certain  Second  Amendment  to  Agreement  of Limited
Partnership   of  the   Partnership,   effective  as  of  January   1,1999  (the
"Agreement").

                  2. The  Partners  desire to  further  amend the  Agreement  to
reflect  the  Partners's  adjusted  Percentage   Interests  resulting  from  the
successful  closing  of  the  offering  of  limited  partner  interests  in  the
Partnership  pursuant  to  the  Partnership's   Confidential  Private  Placement
Memorandum dated September 4, 1998, as amended,  and the subsequent admission of
new Limited Partners to the Partnership.

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

                           Schedule  A-1 is  deleted in its  entirety  and a new
                           Schedule A-2,  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




                                                        -1-


<PAGE>





                                                     ALL THE LIMITED PARTNERS OF
                                                     THE PARTNERSHIP WHOSE NAMES
                                                     APPEARED ON SCHEDULE A-1

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



                                                        -2-


<PAGE>



                                                                    SCHEDULE A-2

                        Schedule of Partnership Interests

                 TEXAS LITHOTRIPSY LIMITED PARTNERSHIP VII, L.P.
                 -----------------------------------------------


General Partner                                           Percentage Interest
---------------                                           -------------------
Lithotripters, Inc.                                        19.22749573%
2008 Litho Place
Fayetteville, NC 28304
Limited Partners

Robert Admire                                               0.38068800%
Joyce Allen                                                 0.27621352%
Mark Allen                                                  0.19034400%
Thomas Arnold                                               328672%
Steven Ash                                                  0.57000000%
John Ballard, III                                           0.27621352%
Charles Bamberger                                           1.60826543%
Marc Barrett                                                2.12657343%
Baylor Health Care System                                   1.14000000%
James Brady                                                 0.19034400%
Harold Calhoun                                              0.19000000%
David Casey                                                 0.19000000%
Franklin Clark                                              0.19034400%
James Cochran                                               1.19692527%
Michael Collini                                             0.57000000%
Donald Cook                                                 0.27621352%
Robert Corwin                                               0.57000000%
Stephen Corwin                                              0.27621352%
Philip Damstra                                              0.35458722%
Jules Delaune                                               0.53164336%
Ruth Delaune                                                0.53164336%

Limited Partners                                          Percentage Interest
----------------                                          -------------------
Robert Dowling                                              0.35458722%
J. Stephen Dryden                                           0.19034400%
Richard Dulany                                              0.19034400%
Glenn Dunnington                                            0.27621352%
Kurt Evans                                                  0.19000000%
John Fairbanks                                              0.57000000%
Christopher Fetner                                          0.76137600%
Fifth Street Corp                                           1.93349466%
Joshua Fine                                                 0.57000000%
Myron Fine                                                  0.19000000%
Manny Forkowitz                                             0.57000000%
Larry Frank                                                 0.19034400%
Gerald Frankel                                              0.76137600%
William Freeborn                                            0.76137600%
Alan Freeman                                                0.27621352%
Steven Frost                                                0.57000000%
Philip Gallina                                              0.19034400%
Kenneth Goldberg                                            0.57000000%
Glen Goldsmith                                              0.27621352%
Mike Goldstein                                              0.57000000%
Carole L. Gordon                                            0.190000000%
Nathan Graves                                               0.57000000%
Rufus Green                                                 0.38000000%
William Grine                                               0.19034400%
Scott Hassell                                               0.38068800%
Wayne Hey                                                   0.70869950%
A. Mason Holden                                             0.27621352%
Ira Hollander                                               1.59493008%



                                                        -3-


<PAGE>



Limited Partners                                          Percentage Interest
----------------
Allen Van Horn                                              0.57000000%
Joseph Jenkins                                              0.19034400%
Dan Johnson                                                 1.32910840%
John Johnson                                                0.53164336%
Sid Jones                                                   1.06328672%
Lillian Jordan                                              0.53164336%
Thomas Jordan                                               0.19034400%
William Jordan                                              0.19034400%
T.S. Kent                                                   0.27621352%
Farid Khoury                                                0.19034400%
Mario Labardini                                             0.19034400%
J.L. LaManna, III                                           0.27621352%
Hugh Lamensdorf                                             1.06328672%
Jeffrey H. Landau                                           0.57000000%
Edward Lee                                                  1.06328672%
Kenneth Licker                                              0.19000000%
Stephen Lieman                                              0.57103200%
Lithotripters, Inc.                                        15.06038783%
Barney Maddox                                               0.27621352%
James Mason                                                 0.19000000%
Roy Carrington Mason                                        0.19000000%
Donald McKay                                                0.57103200%
William Mitchell                                            0.27621352%
Thomas Mobley                                               0.19034400%
Frank Moore, III                                            0.5700000%
Yondell Moore                                               0.19034400%
Dan Myers                                                   0.19034400%
Jerry Newton                                                0.27621352%



                                                        -4-


<PAGE>



Limited Partners                                          Percentage Interest
----------------
Denis Ortiz                                                 0.35458722%
Paris Urology Assoc. Pension                                0.55242705%
Allen Plotkin                                               0.27621352%
Drew Pumphrey                                               1.41792143%
Anthony Rand                                                0.19034400%
Richard Reese                                               0.55242705%
Jack Rice                                                   0.27621352%
 Edward Rietze Estate                                       0.19034400%
William Risk                                                1.38106762%
Donald Ross                                                 0.53164336%
James Saalfield                                             0.89904350%
Jeff Sanders                                                0.57000000%
Nabel Sayed                                                 0.38000000%
Ben Schnitzer                                               0.19000000%
Roger Schoenvogel                                           0.57000000%
Rashinda Singh                                              0.53164336%
Southwest Lithotripter Partners                             7.45776513%
Frank Splann                                                0.19000000%
John Staub                                                  0.27621352%
Donald Stewart                                              0.57000000%
Martha Storrie                                              1.98895343%
Mark Story                                                  1.86075175%
Robert Stroud                                               0.35458722%
Roger Stuart                                                0.19034400%
Agif Syed                                                   0.27621352%
Alan Terry                                                  0.19034400%
Addison Thurman                                             1.06328672%
Arthur Tijerina                                             1.65728114%




                                                        -5-


<PAGE>


Limited Partners                                          Percentage Interest
----------------
Eugene Todd                                                 0.55242705%
Michael Walter                                              0.53164336%
R.D. West                                                   0.18414235%
Jeannie Westerburg                                          0.18414235%
Robert Westerburg                                           0.18414235%
Roger Wolfert                                               0.27621352%
                                                            -----------
TOTAL                                                        100%





                                                        -6-


<PAGE>
                               FOURTH AMENDMENT TO
                       AGREEMENT OF LIMITED PARTNERSHIP OF
                 TEXAS LITHOTRIPSY LIMITED PARTNERSHIP VII, L.P.



     THIS AMENDMENT,  effective as of the 1st day of March, 1999 is entered into
by and among  Lithotripters,  Inc., a North Carolina corporation and the General
Partner of Texas Lithotripsy Limited Partnership VII, L.P. (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 Agreement
of Limited Partnership of Texas Lithotripsy Limited Partnership VII, L.P., dated
as of  September 4, 1998,  as amended by that certain  Amendment to Agreement of
Limited  Partnership  of the  Partnership,  effective as of October 7, 1998,  as
further  amended  by that  certain  Second  Amendment  to  Agreement  of Limited
Partnership of the Partnership,  effective as of January 1,1999,  and as further
amended by that certain Third  Amendment to Agreement of Limited  Partnership of
the Partnership effective as of February 2, 1999 (the "Agreement").

                  2. The  Partners  desire to  further  amend the  Agreement  to
reflect  the  Partners'  adjusted   Percentage   Interests  resulting  from  the
assignment by each of Mark Allen, M.D.  ("Allen"),  J. Scott Hassell ("Hassell")
and Steven Lieman  ("Lieman") of their entire limited  partnership  interests in
the  Partnership  to  the  Partnership.   As  a  consequence  of  the  foregoing
assignments,  Allen,  Hassell and Lieman are no longer  limited  partners of the
Partnership as of the date hereof.

                  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



                                                        -1-


<PAGE>





                                                     ALL THE LIMITED PARTNERS OF
                                                     THE PARTNERSHIP WHOSE NAMES
                                                     APPEARED ON SCHEDULE A-2

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



                                                        -2-


<PAGE>



                                                                    SCHEDULE A-2

                        Schedule of Partnership Interests

                 TEXAS LITHOTRIPSY LIMITED PARTNERSHIP VII, L.P.
                 -----------------------------------------------


General Partner                                          Percentage Interest
---------------                                          -------------------
Lithotripters, Inc.                                          19.449629%
2008 Litho Place
Fayetteville, NC 28304
Limited Partners                                         Percentage Interest
----------------                                         ------------------
Robert Admire                                                 0.385086%
Joyce Allen                                                   0.279404%
Thomas Arnold                                                 1.075570%
Steven Ash                                                    0.576585%
John Ballard, III                                             0.279404%
Charles Bamberger                                             1.626845%
Marc Barrett                                                  2.151141%
Baylor Health Care System                                     1.153170%
James Brady                                                   0.192543%
Harold Calhoun                                                0.192195%
David Casey                                                   0.192195%
Franklin Clark                                                0.192543%
James Cochran                                                 1.210753%
Michael Collini                                               0.576585%
Donald Cook                                                   0.279404%
Robert Corwin                                                 0.576585%
Stephen Corwin                                                0.279404%
Philip Damstra                                                0.358684%
Jules Delaune                                                 0.537785%
Ruth Delaune                                                  0.537785%
Robert Dowling                                                0.358684%
J. Stephen Dryden                                             0.192543%



                                                        -3-


<PAGE>



2008 Litho Place

Richard Dulany                                                0.192543%
Glenn Dunnington                                              0.279404%
Kurt Evans                                                    0.192195%
John Fairbanks                                                0.576585%
Christopher Fetner                                            0.770172%
Fifth Street Corp                                             1.955832%
Joshua Fine                                                    .576585%
Myron Fine                                                    0.192195%
Manny Forkowitz                                               0.576585%
Larry Frank                                                   0.192543%
Gerald Frankel                                                0.770172%
William Freeborn                                              0.770172%
Alan Freeman                                                  0.279404%
Steven Frost                                                  0.576585%
Philip Gallina                                                0.192543%
Kenneth Goldberg                                              0.576585%
Glen Goldsmith                                                0.279404%
Mike Goldstein                                                0.576585%
Carole L. Gordon                                              0.192195%
Nathan Graves                                                 0.576585%
Rufus Green                                                   0.384390%
William Grine                                                 0.192543%
Wayne Hey                                                     0.716887%
A. Mason Holden                                               0.279404%
Ira Hollander                                                 1.613356%
Joseph Jenkins                                                0.192543%
Dan Johnson                                                   1.344463%
John Johnson                                                  0.537785%
Sid Jones                                                     1.075570%



                                                        -4-


<PAGE>



2008 Litho Place

Lillian Jordan                                                0.537785%
Thomas Jordan                                                 0.192543%
William Jordan                                                0.192543%
T.S. Kent                                                     0.279404%
Farid Khoury                                                  0.192543%
Mario Labardini                                               0.192543%
J.L. LaManna, III                                             0.279404%
Hugh Lamensdorf                                               1.075570%
Jeffrey H. Landau                                             0.576585%
Edward Lee                                                    1.075570%
Kenneth Licker                                                0.192195%
Lithotripters, Inc.                                          15.233413%
Barney Maddox                                                 0.279404%
James Mason                                                   0.192195%
Roy Carrington Mason                                          0.192195%
Donald McKay                                                  0.577629%
William Mitchell                                              0.279404%
Thomas Mobley                                                 0.192543%
Frank Moore, III                                              0.576585%
Yondell Moore                                                 0.192543%
Dan Myers                                                     0.192543%
Jerry Newton                                                  0.279404%
Denis Ortiz                                                   0.358684%
Paris Urology Assoc. Pension Plan                             0.558809%
Allen Plotkin                                                 0.279404%
John Pumphrey                                                 1.434302%
Anthony Rand                                                  0.192543%
Richard Reese                                                 0.558809%
Jack Rice                                                     0.279404%



                                                        -5-


<PAGE>


2008 Litho Place

 Edward Rietze Estate                                         0.192543%
William Risk                                                  1.397023%
Donald Ross                                                   0.537785%
James Saalfield                                               0.909430%
Jeff Sanders                                                  0.576585%
Nabel Sayed                                                   0.384390%
Ben Schnitzer                                                 0.192195%
Roger Schoenvogel                                             0.576585%
Rashinda Singh                                                0.537785%
Southwest Lithotripter Partners                               7.543922%
Frank Splann                                                  0.192195%
John Staub                                                    0.279404%
Donald Stewart                                                0.576585%
Martha Storrie                                                2.011931%
Mark Story                                                    1.882248%
Robert Stroud                                                 0.358684%
Roger Stuart                                                  0.192543%
Agif Syed                                                     0.279404%
Alan Terry                                                    0.192543%
Addison Thurman                                               1.075570%
Arthur Tijerina                                               1.676427%
Eugene Todd                                                   0.558809%
Allen Van Horn                                                0.576585%
Michael Walter                                                0.537785%
R.D. West                                                     0.186270%
Jeannie Westerburg                                            0.186270%
Robert Westerburg                                             0.186270%
Roger Wolfert                                                 0.279404%
                                                              ---------
TOTAL                                                          100%




                                                        -6-


<PAGE>