FIRST SUPPLEMENT DATED JUNE 1, 2000 TO THE

                 CONFIDENTIAL PRIVATE PLACEMENT MEMORANDUM DATED

                                 APRIL 21, 2000

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

                  Mobile  Kidney  Stone  Centers  of  California   II,  L.P.,  a
California  limited  partnership (the  "Partnership"),  by this First Supplement
hereby amends and supplements its Confidential  Private Placement  Memorandum of
April 21, 2000 (the "Memorandum").  Capitalized terms used herein are defined in
the Glossary appearing in the Memorandum. Persons who have subscribed for or are
considering  an  investment  in  the  Units  offered  by the  Memorandum  should
carefully review this First Supplement.

Extension of the Offering

                  Pursuant to the authority  given to the General Partner in the
Memorandum, the General Partner hereby elects to extend the offering termination
date to September 28, 2000 (or earlier in the discretion of the General Partner,
upon the sale of all Units as provided in the Memorandum).