SECURITIES AND EXCHANGE COMMISSION

                             Washington, D.C. 20549

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

                                 SCHEDULE 13G/A
                                 (Rule 13d-102)

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

                                 Amendment No. 1

    INFORMATION TO BE INCLUDED IN STATEMENTS PURSUANT TO RULES 13d-1(b), (c)
        AND (d) AND AMENDMENTS THERETO FILED PURSUANT TO 13d-2 UNDER THE
                         SECURITIES EXCHANGE ACT OF 1934

                               MASIMO CORPORATION
                                (Name of Issuer)

                          COMMON STOCK, PAR VALUE $0.001
                         (Title of Class of Securities)

                                    574795100
                                 (CUSIP Number)

                                December 31, 2008
             (Date of Event Which Requires Filing of this Statement)

         Check the appropriate box to designate the rule pursuant to which this
Schedule is filed:

         [ ] Rule 13d-1(b)

         [X] Rule 13d-1(c)

         [ ] Rule 13d-1(d)

-----------

         * The remainder of this cover page shall be filled out for a reporting
person's initial filing on this form with respect to the subject class of
securities, and for any subsequent amendment containing information which would
alter the disclosures provided in a prior cover page.

         The information required in the remainder of this cover page shall not
be deemed to be "filed" for the purpose of Section 18 of the Securities Exchange
Act of 1934 (the "Act") or otherwise subject to the liabilities of that section
of the Act but shall be subject to all other provisions of the Act (however, see
the Notes).





Schedule 13G/A
CUSIP No. 574795100                                                Page 2 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner Partners
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         New York
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   PN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 3 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner Institutional Partners, L.P.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Delaware
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   PN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 4 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         M. H. Davidson & Co.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         New York
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   PN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 5 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner International, Ltd.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         British Virgin Islands
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   CO
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 6 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Serena Limited
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Cayman Islands
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   CO
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 7 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner Healthcare Fund LP
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Delaware
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   PN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 8 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner Healthcare International Ltd.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Cayman Islands
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   CO
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 9 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         MHD Management Co.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         New York
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   PN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 10 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner Advisers Inc.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         New York
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IA
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 11 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Davidson Kempner International Advisors, L.L.C.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Delaware
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   OO
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 12 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         DK Group LLC
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Delaware
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   OO
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 13 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         DK Management Partners LP
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Delaware
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   PN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 14 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         DK Stillwater GP LLC
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         Delaware
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   OO
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 15 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Thomas L. Kempner Jr.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 16 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Marvin H. Davidson
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 17 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Stephen M. Dowicz
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 18 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Scott E. Davidson
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 19 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Michael J. Leffell
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 20 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Timothy I. Levart
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United Kingdom & United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 21 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Robert J. Brivio, Jr.
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 22 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Eric P. Epstein
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 23 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Anthony A. Yoseloff
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 24 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Avram Z. Friedman
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 25 of 44

--------------------------------------------------------------------------------
(1)      NAME OF REPORTING PERSON
         S.S. OR I.R.S. IDENTIFICATION NO. OF ABOVE PERSON
         Conor Bastable
--------------------------------------------------------------------------------
(2)      CHECK THE APPROPRIATE BOX IF A MEMBER OF A GROUP

                                                          (a) [ ]
                                                          (b) [X]
--------------------------------------------------------------------------------
(3)      SEC USE ONLY
--------------------------------------------------------------------------------
(4)      CITIZENSHIP OR PLACE OF ORGANIZATION
                         United States
--------------------------------------------------------------------------------

NUMBER OF       (5)      SOLE VOTING POWER
                                   0
SHARES          ----------------------------------------------------------------

BENEFICIALLY    (6)      SHARED VOTING POWER
                                   0
OWNED BY        ----------------------------------------------------------------

EACH            (7)      SOLE DISPOSITIVE POWER
                                   0
REPORTING       ----------------------------------------------------------------

PERSON WITH     (8)      SHARED DISPOSITIVE POWER
                                   0
--------------------------------------------------------------------------------
       (9)   AGGREGATE AMOUNT BENEFICIALLY OWNED
             BY EACH REPORTING PERSON
                                   0
--------------------------------------------------------------------------------
       (10)  CHECK BOX IF THE AGGREGATE AMOUNT
             IN ROW (9) EXCLUDES CERTAIN SHARES                          [ ]
--------------------------------------------------------------------------------
       (11)  PERCENT OF CLASS REPRESENTED
             BY AMOUNT IN ROW (9)
                                   0.0%
------------------------------------------------------------------------------
       (12)  TYPE OF REPORTING PERSON
                                   IN
------------------------------------------------------------------------------





Schedule 13G/A
CUSIP No. 574795100                                                Page 26 of 44


ITEM 1(a).   NAME OF ISSUER:

             Masimo Corporation (the "Company")

ITEM 1(b).   ADDRESS OF ISSUER'S PRINCIPAL EXECUTIVE OFFICES:

             40 Parker
             Irvine, California 92618

ITEM 2(a).   NAME OF PERSON FILING:

      This Statement is filed by each of the entities and persons listed below,
all of whom together are referred to herein as the "Reporting Persons":

             (i)      Davidson Kempner Partners, a New York limited
                      partnership ("DKP");

             (ii)     Davidson Kempner Institutional Partners, L.P., a
                      Delaware limited partnership ("DKIP");

             (iii)    M. H. Davidson & Co., a New York limited partnership
                      ("CO");

             (iv)     Davidson Kempner International, Ltd., a British
                      Virgin Islands corporation ("DKIL");

             (v)      Serena Limited, a Cayman Islands corporation
                      ("Serena");

             (vi)     Davidson Kempner Healthcare Fund LP, a Delaware
                      limited partnership ("DKHF");

             (vii)    Davidson Kempner Healthcare International Ltd., a
                      Cayman Islands corporation ("DKHI");

             (viii)   MHD Management Co., a New York limited partnership
                      and the general partner of DKP ("MHD");

             (ix)     Davidson Kempner Advisers Inc., a New York
                      corporation and the general partner of DKIP ("DKAI"),
                      which is registered as an investment adviser with the
                      U.S. Securities and Exchange Commission;

             (x)      Davidson Kempner International Advisors, L.L.C., a
                      Delaware limited liability company and the manager of
                      DKIL and Serena ("DKIA");

             (xi)     DK Group LLC, a Delaware limited liability company
                      and the general partner of DKHF ("DKG");

             (xii)    DK Management Partners LP, a Delaware limited
                      partnership and the investment manager of DKHI
                      ("DKMP");





Schedule 13G/A
CUSIP No. 574795100                                                Page 27 of 44

             (xiii)   DK Stillwater GP LLC, a Delaware limited liability
                      company and the general partner of DKMP ("DKS"); and

             (xiv)    Messrs. Thomas L. Kempner, Jr., Marvin H. Davidson,
                      Stephen M. Dowicz, Scott E. Davidson, Michael J.
                      Leffell, Timothy I. Levart, Robert J. Brivio, Jr., Anthony
                      A. Yoseloff, Eric P. Epstein, Avram Z. Friedman and Conor
                      Bastable (collectively, the "Principals"), who are the
                      general partners of CO and MHD, the sole managing members
                      of DKIA and DKG and the sole stockholders of DKAI. Messrs.
                      Thomas L. Kempner, Jr. and Timothy I. Levart are Executive
                      Managing Member and Deputy Executive Managing Member,
                      respectively, of DKS. Each of Messrs. Kempner and Levart,
                      together with Messrs. Marvin H. Davidson, Stephen M.
                      Dowicz, Scott E. Davidson, Michael J. Leffell, Robert J.
                      Brivio, Jr., Anthony A. Yoseloff, Eric P. Epstein, Avram
                      Z. Friedman and Conor Bastable are limited partners of
                      DKMP.

ITEM 2(b).   ADDRESS OF PRINCIPAL BUSINESS OFFICE:

      The address of the principal business office of each of the Reporting
Persons is c/o Davidson Kempner Partners, 65 East 55th Street, 19th Floor, New
York, New York 10022.

ITEM 2(c).   CITIZENSHIP:

             (i)      DKP - a New York limited partnership

             (ii)     DKIP - a Delaware limited partnership

             (iii)    CO - a New York limited partnership

             (iv)     DKIL - a British Virgin Islands corporation

             (v)      Serena - a Cayman Islands corporation

             (vi)     DKHF - a Delaware limited partnership

             (vii)    DKHI - a Cayman Islands corporation

             (viii)   MHD - a New York limited partnership

             (ix)     DKAI - a New York corporation

             (x)      DKIA - a Delaware limited liability company

             (xi)     DKG - a Delaware limited liability company

             (xii)    DKMP - a Delaware limited partnership

             (xiii)   DKS - a Delaware limited liability company

             (xiv)    Thomas L. Kempner, Jr. - United States





Schedule 13G/A
CUSIP No. 574795100                                                Page 28 of 44


             (xv)     Marvin H. Davidson - United States

             (xvi)    Stephen M. Dowicz - United States

             (xvii)   Scott E. Davidson -United States

             (xviii)  Michael J. Leffell - United States

             (xix)    Timothy I. Levart - United Kingdom & United States

             (xx)     Robert J. Brivio, Jr. - United States

             (xxi)    Eric P. Epstein - United States

             (xxii)   Anthony A. Yoseloff - United States

             (xxiii)  Avram Z. Friedman - United States

             (xxiv)   Conor Bastable - United States

ITEM 2(d).   TITLE OF CLASS OF SECURITIES:

      COMMON STOCK, PAR VALUE $0.001

ITEM 2(e).   CUSIP NUMBER:

      574795100

ITEM 3. IF THIS STATEMENT IS FILED PURSUANT TO 13d-1(b) OR 13d-2(b) OR (c),
CHECK WHETHER THE PERSON FILING IS A:

             (a)[ ]    Broker or dealer registered under Section 15
                       of the Act;

             (b)[ ]    Bank as defined in Section 3(a)(6) of the
                       Act;

             (c)[ ]    Insurance Company as defined in Section
                       3(a)(19) of the Act;

             (d)[ ]    Investment Company registered under Section 8
                       of the Investment Company Act of 1940;

             (e)[ ]    Investment Adviser registered under Section 203
                       of the Investment Advisers Act of 1940:  see Rule
                       13d-1(b)(1)(ii)(E);

             (f)[ ]    Employee Benefit Plan, Pension Fund which is subject
                       to the provisions of the Employee Retirement Income
                       Security Act of 1974 or Endowment Fund; see
                       Rule 13d-1(b)(1)(ii)(F);

             (g)[ ]    Parent Holding Company, in accordance with
                       Rule 13d-1(b)(ii)(G);

             (h)[ ]    Savings Associations as defined in Section
                       3(b) of the Federal Deposit Insurance Act;





Schedule 13G/A
CUSIP No. 574795100                                                Page 29 of 44


             (i)[ ]    Church Plan that is excluded from the definition
                       of an investment company under Section 3(c)(14)
                       of the Investment Company Act of 1940;

             (j)[ ]    Group, in accordance with Rule 13d-1(b)(1)(ii)(J).

ITEM 4.  OWNERSHIP.

      A. DKP

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      B. DKIP

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      C. CO

        (a) Amount beneficially owned: 0

        (b) Percent of class: 0.0%

        (c) Number of shares as to which such person has:

            (i) sole power to vote or to direct the vote: 0

            (ii) shared power to vote or to direct the vote: 0

            (iii) sole power to dispose or to direct the disposition: 0





Schedule 13G/A
CUSIP No. 574795100                                                Page 30 of 44

            (iv) shared power to dispose or to direct the disposition: 0

      D. DKIL

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      E. Serena

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      F. DKHF

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      G. DKHI

         (a) Amount beneficially owned: 0





Schedule 13G/A
CUSIP No. 574795100                                                Page 31 of 44

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      H. MHD

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      I. DKAI

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      J. DKIA

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:





Schedule 13G/A
CUSIP No. 574795100                                                Page 32 of 44

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      K. DKG

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      L. DKMP

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      M. DKS

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0





Schedule 13G/A
CUSIP No. 574795100                                                Page 33 of 44

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      N. Thomas L. Kempner, Jr.

        a) Amount beneficially owned: 0

        b) Percent of class: 0.0%

        c) Number of shares as to which such person has:

           (i) sole power to vote or to direct the vote: 0

           (ii) shared power to vote or to direct the vote: 0

           (iii) sole power to dispose or to direct the disposition: 0

           (iv) shared power to dispose or to direct the disposition: 0

      O. Marvin H. Davidson

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      P. Stephen M. Dowicz

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0




Schedule 13G/A
CUSIP No. 574795100                                                Page 34 of 44

      Q. Scott E. Davidson

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      R. Michael J. Leffell

         (a) Amount beneficially owned. 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      S. Timothy I. Levart

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      T. Robert J. Brivio, Jr.

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%




Schedule 13G/A
CUSIP No. 574795100                                                Page 35 of 44


         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      U. Eric P. Epstein

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      V. Anthony A. Yoseloff

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      W. Avram Z. Friedman

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0



Schedule 13G/A
CUSIP No. 574795100                                                Page 36 of 44


             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

      X. Conor Bastable

         (a) Amount beneficially owned: 0

         (b) Percent of class: 0.0%

         (c) Number of shares as to which such person has:

             (i) sole power to vote or to direct the vote: 0

             (ii) shared power to vote or to direct the vote: 0

             (iii) sole power to dispose or to direct the disposition: 0

             (iv) shared power to dispose or to direct the disposition: 0

ITEM 5.  OWNERSHIP OF FIVE PERCENT OR LESS OF A CLASS.

         If this statement is being filed to report the fact that as of the date
hereof the reporting person has ceased to be the beneficial owner of more than
five percent of the class of securities, check the following [X].

ITEM 6.  OWNERSHIP OF MORE THAN FIVE PERCENT ON BEHALF OF ANOTHER PERSON.

         Not applicable.

ITEM 7.  IDENTIFICATION AND CLASSIFICATION OF THE SUBSIDIARY WHICH
         ACQUIRED THE SECURITY BEING REPORTED ON BY THE PARENT
         HOLDING COMPANY.

         Not applicable.

ITEM 8.  IDENTIFICATION AND CLASSIFICATION OF MEMBERS OF THE GROUP.

         See Item 4.

ITEM 9.  NOTICE OF DISSOLUTION OF GROUP.

         Not applicable.

ITEM 10. CERTIFICATION.  (if filing pursuant to Rule 13d-1(c))

      Each of the Reporting Persons hereby makes the following certification:





Schedule 13G/A
CUSIP No. 574795100                                                Page 37 of 44


      By signing below we certify that, to the best of our knowledge and
belief, the securities referred to above were not acquired and are not held for
the purpose of or with the effect of changing or influencing the control of the
issuer of the securities and were not acquired and are not held in connection
with or as a participant in any transaction having that purpose or effect.






Schedule 13G/A
CUSIP No. 574795100                                                Page 38 of 44


                                   SIGNATURES

      After reasonable inquiry and to the best of our knowledge and belief,
the undersigned certify that the information set forth in this statement is
true, complete and correct.

DATED:  February 17, 2009          DAVIDSON KEMPNER PARTNERS
                                   By: MHD Management Co.,
                                     its General Partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Managing Partner

                                   DAVIDSON KEMPNER INSTITUTIONAL
                                   PARTNERS, L.P.
                                   By: Davidson Kempner Advisers Inc.,
                                   its General Partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: President

                                   M.H. DAVIDSON & CO.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Managing Partner

                                   DAVIDSON KEMPNER INTERNATIONAL,
                                   LTD.
                                   By: Davidson Kempner International Advisors,
                                   L.L.C.,
                                   its Investment Manager

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   SERENA LIMITED
                                   By: Davidson Kempner International Advisors,
                                   L.L.C.,
                                   its Investment Manager

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member



Schedule 13G/A
CUSIP No. 574795100                                                Page 39 of 44


                                   DAVIDSON KEMPNER HEALTHCARE
                                   FUND LP
                                   By:  DK Group LLC,
                                   its General Partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DAVIDSON KEMPNER HEALTHCARE
                                   INTERNATIONAL LTD.
                                   By:  DK Management Partners LP,
                                   its Investment Manager
                                   By:  DK Stillwater GP LLC,
                                   its general partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   MHD MANAGEMENT CO.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Managing Partner

                                   DAVIDSON KEMPNER ADVISERS INC.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: President

                                   DAVIDSON KEMPNER INTERNATIONAL
                                   ADVISORS, L.L.C.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DK GROUP LLC

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member





Schedule 13G/A
CUSIP No. 574795100                                                Page 40 of 44

                                   DK MANAGEMENT PARTNERS LP
                                   By: DK Stillwater GP LLC, its general partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DK STILLWATER GP LLC

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Thomas L. Kempner, Jr.

                                   /s/ Marvin H. Davidson
                                   ----------------------------------
                                   Marvin H. Davidson

                                   /s/ Stephen M. Dowicz
                                   ----------------------------------
                                   Stephen M. Dowicz

                                   /s/ Scott E. Davidson
                                   ----------------------------------
                                   Scott E. Davidson

                                   /s/ Michael J. Leffell
                                   ----------------------------------
                                   Michael J. Leffell

                                   /s/ Timothy I. Levart
                                   ----------------------------------
                                   Timothy I. Levart

                                   /s/ Robert J. Brivio, Jr.
                                   -------------------------
                                   Robert J. Brivio, Jr.

                                   /s/ Eric P. Epstein
                                   ----------------------------------
                                   Eric P. Epstein

                                   /s/ Anthony A. Yoseloff
                                   ----------------------------------
                                   Anthony A. Yoseloff

                                   /s/ Avram Z. Friedman
                                   ----------------------------------
                                   Avram Z. Friedman

                                   /s/ Conor Bastable
                                   ----------------------------------
                                   Conor Bastable




Schedule 13G/A
CUSIP No. 574795100                                                Page 41 of 44


                                    EXHIBIT 1

                           JOINT ACQUISITION STATEMENT

                            PURSUANT TO RULE 13d-1(k)

     The undersigned acknowledge and agree that the foregoing statement on
Schedule 13G is filed on behalf of each of the undersigned and that all
subsequent amendments to this statement on Schedule 13G, shall be filed on
behalf of each of the undersigned without the necessity of filing additional
joint acquisition statements. The undersigned acknowledge that each shall be
responsible for the timely filing of such amendments, and for the completeness
and accuracy of the information concerning him or it contained therein, but
shall not be responsible for the completeness and accuracy of the information
concerning the others, except to the extent that he or it knows or has reason to
believe that such information is inaccurate.

DATED:  February 17, 2009          DAVIDSON KEMPNER PARTNERS
                                   By: MHD Management Co.,
                                     its General Partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Managing Partner

                                   DAVIDSON KEMPNER INSTITUTIONAL
                                   PARTNERS, L.P.
                                   By: Davidson Kempner Advisers Inc.,
                                   its General Partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: President

                                   M.H. DAVIDSON & CO.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Managing Partner

                                   DAVIDSON KEMPNER INTERNATIONAL,
                                   LTD.
                                   By: Davidson Kempner International Advisors,
                                   L.L.C.,
                                   its Investment Manager

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member





Schedule 13G/A
CUSIP No. 574795100                                                Page 42 of 44


                                   SERENA LIMITED
                                   By: Davidson Kempner International Advisors,
                                   L.L.C.,
                                   its Investment Manager

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DAVIDSON KEMPNER HEALTHCARE
                                   FUND LP
                                   By:  DK Group LLC,
                                   its General Partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DAVIDSON KEMPNER HEALTHCARE
                                   INTERNATIONAL LTD.
                                   By:  DK Management Partners LP,
                                   its Investment Manager
                                   By:  DK Stillwater GP LLC,
                                   its general partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   MHD MANAGEMENT CO.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Managing Partner

                                   DAVIDSON KEMPNER ADVISERS INC.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: President

                                   DAVIDSON KEMPNER INTERNATIONAL
                                   ADVISORS, L.L.C.

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member





Schedule 13G/A
CUSIP No. 574795100                                                Page 43 of 44


                                   DK GROUP LLC

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DK MANAGEMENT PARTNERS LP
                                   By: DK Stillwater GP LLC, its general partner

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   DK STILLWATER GP LLC

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Name:  Thomas L. Kempner, Jr.
                                   Title: Executive Managing Member

                                   /s/ Thomas L. Kempner, Jr.
                                   ----------------------------------
                                   Thomas L. Kempner, Jr.

                                   /s/ Marvin H. Davidson
                                   ----------------------------------
                                   Marvin H. Davidson

                                   /s/ Stephen M. Dowicz
                                   ----------------------------------
                                   Stephen M. Dowicz

                                   /s/ Scott E. Davidson
                                   ----------------------------------
                                   Scott E. Davidson

                                   /s/ Michael J. Leffell
                                   ----------------------------------
                                   Michael J. Leffell

                                   /s/ Timothy I. Levart
                                   ----------------------------------
                                   Timothy I. Levart

                                   /s/ Robert J. Brivio, Jr.
                                   -------------------------
                                   Robert J. Brivio, Jr.

                                   /s/ Eric P. Epstein
                                   ----------------------------------
                                   Eric P. Epstein

                                   /s/ Anthony A. Yoseloff
                                   ----------------------------------
                                   Anthony A. Yoseloff

                                   /s/ Avram Z. Friedman
                                   ----------------------------------
                                   Avram Z. Friedman





Schedule 13G/A
CUSIP No. 574795100                                                Page 44 of 44


                                   /s/ Conor Bastable
                                   ----------------------------------
                                   Conor Bastable