EXHIBIT 3.4



CT 07 

                                 F 96O617000029


                            CERTIFICATE OF AMENDMENT

                                       OF

                          CERTIFICATE OF INCORPORATION

                                       OF

                          MEDICAL STERILIZATION, INC.

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

           Under Section 805 of the New York Business Corporation Law

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

IT IS HEREBY CERTIFIED THAT:

         FIRST: The name of the corporation is Medical Sterilization,  Inc. (the
"Corporation").  The original  name under which the  Corporation  was formed was
General Sterilization Services, Inc.

         SECOND:  The Certificate of  Incorporation of the Corporation was filed
by the Department of State of New York on May 27, 1982. Restated Certificates of
Incorporation  and Certificates of Amendment were filed on May 12, 1983,  August
5, 1983, May 24, 1989, January 4, 1990 and November 28, 1994.

         THIRD:  The  amendment  of  the  Certificate  of  Incorporation  of the
Corporation  effected  by  this  Certificate  of  Amendment  is  to  permit  the
Corporation  to  issue  certain   additional   securities   without   triggering
anti-dilution  provisions with respect to the Corporation's Series B Convertible
Preferred Stock and Series C Convertible Preferred Stock.

         FOURTH:  To  accomplish  the  foregoing  amendment,   Paragraph  FOURTH
A(g)(vi)  of the  Certificate  of  Incorporation  of the  Corporation  is hereby
amended to read in its entirety as follows:




                                      -2-


                  (vi) Certain Issues of Common Stock Excepted.  Anything herein
         to the contrary notwithstanding,  the Corporation shall not be required
         to make  any  adjustment  of the  Conversion  Price  in the case of the
         issuance of: stock options,  stock awards or rights to purchase  shares
         of Common  Stock  issued or awarded  pursuant to any stock plan adopted
         and  approved by the Board of Directors  of the  Corporation,  provided
         that, for so long as any shares of Series B Convertible Preferred Stock
         of Series C Convertible  Preferred Stock are outstanding,  at least one
         director  nominated  by the holders of the then  outstanding  shares of
         Series B Convertible Preferred Stock and Series C Convertible Preferred
         Stock shall have voted in favor of the  adoption  and  approval of such
         stock plan;  the issuance of 1,542,000  shares of Series C  Convertible
         Preferred  Stock with a conversion  price of $1 .00 per share;  and the
         issuance of warrants to purchase  80,000  shares of common stock of the
         Corporation at a price of $1.00 per share.

         FIFTH:  The foregoing  amendment of the Certificate of Incorporation of
the  Corporation  was  authorized by the Board of Directors of the  Corporation,
followed by the consent of the holders of two-thirds of the  outstanding  shares
of Series B Convertible Preferred Stock and Series C Convertible Preferred Stock
in the  aggregate,  and a majority  of the votes  cast by the  holders of Common
Stock  entitled to vote on the said  amendment  of the Restated  Certificate  of
Incorporation.

         IN WITNESS  WHEREOF,  the  undersigned  subscribed this document on the
date set forth below and do hereby affirm, under the penalties of perjury,  that
the statements  contained  herein have been examined by the  undersigned and are
true and correct.

Dated: May 31, 1996


                                     /s/ D. Michael Deignan
                                     -----------------------------------
                                     D. Michael Deignan, Chief Executive Officer
                                     and President

                                     /s/ Harvey Cohen
                                     -----------------------------------
                                     Harvey Cohen, Secretary





CT-07

                                 F 96O617000029


                            CERTIFICATE OF AMENDMENT

                                       OF

                          MEDICAL STERILIZATION, INC.

                 UNDER SECTION 805 OF THE BUSINESS CORPORATION

                                LAW OF NEW YORK

                                      ICC

                               STATE OF NEW YORK
                              DEPARTMENT OF STATE
                              FILED JUNE 17 1996
                              TAX $__________
                              BY:  JCC
                                 ------------

                                     NASSAU


                           TESTA, HURWITZ & THIBEAULT
                                125 HIGH STREET
                               HIGH STREET TOWER
                                BOSTON, MA 02110




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