UNITED STATES SECURITIES AND EXCHANGE COMMISSION Washington, D.C. 20549 SCHEDULE 13G/A Under the Securities Exchange Act of 1934 Amendment No. 1 Centene Corp. (Name of Issuer) Common Stock (Title of Class of Securities) 15135B101 (CUSIP Number) December 31, 2006 (Date of Event which Requires Filing of this Statement) Check the appropriate box to designate the rule pursuant to which this Schedule is filed: [ X ] Rule 13d-1(b) [ ] Rule 13d-1(c) [ ] Rule 13d-1(d) CUSIP No. 15135B101 1.Names of Reporting Persons. Longwood Investment Advisors, Inc. I.R.S. Identification Nos. of above persons (entities only). 23-2745059 2.Check the Appropriate Box if a Member of a Group (a) [ ] (b) [ X ] 3.SEC Use Only 4.Citizenship or Place of Incorporaion Pennsylvania, United States Number of 5.Sole Voting Power 0 Shares Beneficially 6.Shared Voting Power None Owned by Each 7.Sole Dispositive Power 0 Reporting Person With 8.Shared Dispositive Power None 9.Aggregate Amount Beneficially Owned by Each Reporting Person None 10.Check if the Aggregate Amount in Row (9) Excludes Certain Shares [ ] 11.Percent of Class Represented by Amount in Row (9) 0.00% 12.Type of Reporting Person: IA Item 1(a). Name of Issuer: Centene Corp. Item 1(b). Address of Issuer's Principal Executive Offices: 7711 CARONDELET AVE SUITE 800 ST LOUIS MO 63105 Item 2(a). Name of Person Filing Item 2(b). Address of Principal Business Office or, if None, Residence Item 2(c). Citizenship Longwood Investment Advisors, Inc. 1060 First Avenue, Suite 400 King of Prussia, PA 19406 Item 2(d). Title of Class of Securities: Common Stock Item 2(e). CUSIP Number: 15135B101 Item 3. If This Statement is Filed Pursuant to 240.13d-1(b) or 240.13d-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) X An investment adviser in accordance with 240.13d-1(b)(1)(ii)(E); (f) - An employee benefit plan or endowment fund in accordance with 240.13d-1(b)(1)(ii)(F); (g) - A parent holding company or control person in accordance with 240.13d- 1(b)(1)(ii)(G); (h) - A savings association as defined in Section 3(b) of the Federal Deposit Insurance Act; (i) - A 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 240.13d-1(b)(1)(ii)(J). Item 4. Ownership: a. Amount beneficially owned: 0 b. Percent of Class: 0.00% c. Number of shares as to which the person has: (i) Sole power to vote or to direct the vote 0 (ii) Shared power to vote or to direct the vote None (iii)Sole power to dispose or to direct the disposition of 0 (iv) Shared power to dispose or to direct the disposition None Item 5. Ownership of Five Percent or Less of a Class: [ 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 of Control Person: Not applicable. Item 8. Identification and Classification of Members of the Group: Not applicable. Item 9. Notice of Dissolution of Group: Not applicable. Item 10.Certification: By signing below I certify that, to the best of my 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. SIGNATURE After reasonable inquiry and to the best of my knowledge and belief, I certify that the information set forth in this statement is true, complete and correct. Date February 12, 2007 By:/s/ Robert A. Davidson Robert A. Davidson Title: President