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                                                                   EXHIBIT 3.109

                                     CHARTER
                                       OF
                               PCA OF DENVER, INC.

                                   ARTICLE ONE

                                      NAME

            The name of the corporation is PCA of Denver, Inc.

                                   ARTICLE TWO

                               PROFIT CORPORATION

            The corporation is organized for profit.

                                  ARTICLE THREE

                           REGISTERED OFFICE AND AGENT

            The initial registered office of the corporation is located at 20
Burton Hills Boulevard, Nashville, Davidson County, Tennessee 37215. The initial
registered agent of the corporation at its registered office is Brian C. Carr.

                                  ARTICLE FOUR

                                PRINCIPAL OFFICE

            The mailing address of the initial principal office of the
corporation is 20 Burton Hills Boulevard, Suite 220, Nashville, Tennessee 37215.

                                  ARTICLE FIVE

                                AUTHORIZED SHARES

            The total number of shares of all classes of capital stock which the
Corporation shall have the authority to issue is one thousand (1,000) shares of
common stock, $.01 par value per share, with unlimited voting rights and rights
to receive the net assets of the corporation upon dissolution.

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                                   ARTICLE SIX

                           INITIAL BOARD OF DIRECTORS

            The initial Board of Directors shall consist of one member whose
name and address are as follows:

                                  Brian C. Carr
                     Pathology Consultants of America, Inc.
                            20 Burton Hills Boulevard
                                    Suite 220
                           Nashville, Tennessee 37215

                                  ARTICLE SEVEN

                        LIMITATION OF DIRECTOR LIABILITY

            A director of the corporation shall not be liable to the corporation
or to its shareholders for monetary damages for breach of fiduciary duty as a
director, except for (a) any breach of the director's duty of loyalty to the
corporation or its shareholders; (b) acts or omissions not in good faith or
which involve intentional misconduct or a knowing violation of law; or (c) under
Section 48-18-304 of the Tennessee Business Corporation Act (the "Act") Any
repeal or modification of the provisions of this Article Seven by the
shareholders of the corporation shall be prospective only, and shall not
adversely affect any limitation on the personal liability of a director of the
corporation with respect to any act or omission occurring prior to the effective
date of such rcpeal or modification. If the Act is hereafter amended to
authorize the further elimination or limitation of the liability of directors,
then the liability of a director of the corporation, in addition to the
limitation on liability provided herein, shall be limited to the fullest extent
permitted by such amended Act. In the event that any of the provisions of this
Article Seven (including any provision within a single sentence) is held by a
court of competent jurisdiction to be invalid, void or otherwise unenforceable,
the remaining provisions are sever able and shall remain enforceable to the
fullest extent permitted by law.

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                                  ARTICLE EIGHT

                                  INCORPORATOR

            The name and address of the incorporator are as follows:

                                Peter C. November
                                Alston & Bird LLP
                           1201 West Peachtree Street
                           Atlanta, Georgia 30309-3424

            IN WITNESS WHEREOF, the undersigned executes this Charter this 11th
day of December, 1997.


                                                    /s/ Peter C. November
                                              ----------------------------------
                                              Peter C. November
                                              Incorporator

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