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                                                                   EXHIBIT 3.1

                        RESTATED CERTIFICATE OF INCORPORATION
                                          OF
                                     UROCOR, INC.

                       (Originally incorporated under the name
                          "CytoDiagnostics - Delaware, Inc."
                                 on October 14, 1988)


     FIRST:  The name of the Corporation is UroCor, Inc.

     SECOND:  The registered office of the Corporation in the State of 
Delaware is located at Corporation Trust Center, 1209 Orange Street in the 
City of Wilmington, County of New Castle.  The name and address of its 
registered agent at such address is The Corporation Trust Company.

     THIRD:  The purpose of the Corporation is to engage in any lawful act or 
activity for which corporations may be organized under the General 
Corporation Law of Delaware.

     FOURTH:  The total number of shares of capital stock that the 
Corporation shall have authority to issue is 26,579,759 of which 6,000,000 
shares of the par value of $.01 per share shall be a class designated 
Preferred Stock ("Preferred Stock"), 20,000,000 shares of the par value of 
$.01 per share shall be a class designated Common Stock ("Common Stock"), 
513,093 shares of the par value of $.01 per share shall be a class designated 
Class A Stock ("Class A Stock") and 66,666 shares of the par value of $.01 
per share shall be a class designated Class B Stock ("Class B Stock").

A.   1991 SERIES A PREFERRED STOCK, SERIES I PREFERRED STOCK, SERIES B 
     PREFERRED STOCK, SERIES C PREFERRED STOCK, SERIES D PREFERRED STOCK, 
     SERIES E PREFERRED STOCK AND SERIES EG PREFERRED STOCK.

     One series of Preferred Stock is designated as 1991 Series A Preferred 
Stock, par value $.01 per share (the "1991 Series A Preferred Stock"), of the 
Corporation.  One series of Preferred Stock is designated as Series I 
Preferred Stock, par value $.01 per share (the "Series I Preferred Stock"), 
of the Corporation.  One series of Preferred Stock is designated as Series B 
Preferred Stock, par value $.01 per share (the "Series B Preferred Stock"), 
of the Corporation.  One series of Preferred Stock is designated as Series C 
Preferred Stock, par value $.01 per share (the "Series C Preferred Stock"), 
of the Corporation.  One series of Preferred Stock is designated as Series D 
Preferred Stock, par value $.01 per share (the "Series D Preferred Stock"), 
of the Corporation.  One series of Preferred Stock is designated as Series E 
Preferred Stock, par value $.01 per share (the "Series E Preferred Stock"), 
of the Corporation.  One series of Preferred Stock is designated as Series EG 
Preferred Stock, par value $.01 per share (the "Series EG Preferred Stock"), 
of the Corporation.  The Series E Preferred Stock and the Series EG Preferred 
Stock shall together be referred to herein as the "Series E/EG Preferred 
Stock", unless the context shall otherwise require in which case the term 
"Series E/EG Preferred Stock" shall refer to either the Series E Preferred 
Stock or the Series EG Preferred Stock, as the case may be.

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     The number of shares constituting the 1991 Series A Preferred Stock 
shall be 1,199,999.  The number of shares constituting the Series I Preferred 
Stock shall be 80,000.  The number of shares constituting the Series B 
Preferred Stock shall be 1,467,608.  The number of shares constituting the 
Series C Preferred Stock shall be 981,071.  The number of shares constituting 
the Series D Preferred Stock shall be 1,154,397.  The number of shares 
constituting the Series E Preferred Stock shall be 763,320.  The number of 
shares constituting the Series EG Preferred Stock shall be 60,000.

     The 1991 Series A Preferred Stock, the Series I Preferred Stock, the 
Series B Preferred Stock, the Series C Preferred Stock, the Series D 
Preferred Stock and the Series E/EG Preferred Stock and shall together be 
referred to herein as the "Designated Preferred Stock".

     The voting powers, designations, preferences and relative, 
participating, optional or other special rights of the 1991 Series A 
Preferred Stock, Series I Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock and the Series E/EG Preferred Stock 
and the qualifications, limitations or restrictions thereof, are as follows:

     1.   DIVIDENDS AND DISTRIBUTIONS.

          (a)  The holders of shares of Designated Preferred Stock shall be
entitled to receive, when, as and if declared by the Board of Directors of the
Corporation out of funds legally available for the purpose, dividends equal to
the product of:

               (i)  the aggregate per share amount of any dividend declared on
     the Common Stock, the Class A Stock and the Class B Stock, and, in the
     event any dividend were declared on only one of such classes of stock, or
     on only two of such classes of stock, the aggregate per share amount of 
     any such dividend, as the case may be, since the immediately preceding 
     payment of dividends on Designated Preferred Stock; and

              (ii) the number of shares of Common Stock into which a share of
     Designated Preferred Stock is convertible on the date on which the 
     dividend is to be paid;

and the Corporation shall declare a cash dividend on the Designated Preferred 
Stock as provided in this Section 1(a) immediately after it declares a cash 
dividend on the Common Stock, the Class A Stock and/or the Class B Stock, and 
no dividends shall be declared on the Common Stock, the Class A Stock or the 
Class B Stock, unless the Corporation has funds legally available for the 
payment of such dividends on such classes of stock and for the payment of the 
dividends contemplated by this Section 1 on the Designated Preferred Stock, 
and no dividend shall be paid with respect to the Common Stock, the Class A 
Stock or the Class B Stock, unless and until a dividend is paid with respect 
to all shares of Designated Preferred Stock as contemplated by this Section 
1.  The Board of Directors of the Corporation may fix a record date for the 
determination of holders of shares of the Designated Preferred Stock entitled 
to receive payment of a dividend declared thereon, which record date shall be 
no more than 60 days prior to the date fixed for the payment thereof.

          (b)  The holders of shares of the Designated Preferred Stock shall 
be entitled to receive any non-cash dividend or other distribution 
(including, without limitation, any distribution of other or additional stock 
or other securities or property or rights or warrants to subscribe for or 
purchase Common Stock or other securities of the Corporation or any of its 

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subsidiaries by way of dividend or spin-off, issuance of rights, or 
reclassification, recapitalization or similar corporate rearrangement) which 
the Corporation shall at any time or from time to time declare, order, pay or 
make on the Common Stock, the Class A Stock and/or the Class B Stock, or, in 
the event such dividend or distribution is declared, ordered, paid or made on 
only one of such classes of stock, or on only two of such classes of stock, 
such dividend or distribution, other than a dividend payable in shares of 
Common Stock or a subdivision of the outstanding shares of Common Stock (by 
reclassification or otherwise), and the Corporation at the same time it 
declares, orders, pays or makes such dividend or distribution on the Common 
Stock, the Class A Stock and/or the Class B Stock, shall declare, order, make 
and pay such dividend or distribution on the Designated Preferred Stock, in 
an amount per share equal to the product of:

               (i)  the aggregate per share amount of any such dividend or
     distribution declared, ordered, paid or made on the Common Stock, the
     Class A Stock and the Class B Stock, and, in the event any such dividend 
     or distribution were declared, ordered, paid or made on only one of such
     classes of stock, or on only two of such classes of stock, the aggregate
     per share amount of any such dividend or distribution; and

              (ii) the number of shares of Common Stock into which a share of
     Designated Preferred Stock is convertible on the date on which such
     dividend or distribution is to be paid or made.

No non-cash dividend or other distribution (other than a dividend payable in 
Common Stock or a subdivision of the outstanding shares of Common Stock) 
shall be paid with respect to the Common Stock, the Class A Stock or the 
Class B Stock, unless and until such a dividend or distribution is paid with 
respect to all shares of Designated Preferred Stock as contemplated by this 
Section 1.

     2.   VOTING RIGHTS.  The holders of shares of Designated Preferred Stock
shall have the following voting rights:

          (a)  Each share of Designated Preferred Stock shall entitle the 
holder thereof to one vote multiplied by the number of shares of Common Stock 
into which such share of Designated Preferred Stock is convertible on the 
record date for such vote, on all matters submitted to a vote of the 
stockholders of the Corporation.

          (b)  Except as otherwise required by law or by the provisions of 
this Restated Certificate of Incorporation, (i) the holders of 1991 Series A 
Preferred Stock shall not be entitled to vote separately as a series on any 
matter submitted to a vote of the stockholders of the Corporation, (ii) the 
holders of shares of Series I Preferred Stock shall not be entitled to vote 
separately as a series on any matter submitted to a vote of the stockholders 
of the Corporation, (iii) the holders of shares of Series B Preferred Stock 
shall not be entitled to vote separately as a series on any matter submitted 
to a vote of the stockholders of the Corporation, (iv) the holders of shares 
of Series C Preferred Stock shall not be entitled to vote separately as a 
series on any matter submitted to a vote of the stockholders of the 
Corporation, (v) the holders of shares of Series D Preferred Stock shall not 
be entitled to vote separately as a series on any matter submitted to a vote 
of the stockholders of the Corporation and (vi) the holders of shares of 
Series E/EG Preferred Stock shall not be entitled to vote separately as a 
series on any matter submitted to a vote of the stockholders of the 
Corporation.

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     3.   LIQUIDATION.

          (a)  FIRST PREFERENCE.  In the event of any liquidation, dissolution
or winding up of the affairs of the Corporation, whether voluntary or
involuntary, the holders of record of the issued and outstanding shares of
Designated Preferred Stock and the holders of record of the issued and
outstanding shares of Class A Stock shall be entitled to receive, out of the
assets of the Corporation available for distribution, prior and in preference 
to any distribution of any of the assets of the Corporation to the holders of
Common Stock or to the holders of Class B Stock or otherwise, amounts per share
as follows:

               (i) the holders of record of the issued and outstanding shares
     of 1991 Series A Preferred Stock shall be entitled to receive an amount 
     per share equal to $1.25 plus an amount equal to all dividends accrued on
     the 1991 Series A Preferred Stock but unpaid at the date of such payment;

              (ii) the holders of record of the issued and outstanding shares
     of Series B Preferred Stock shall be entitled to receive an amount per
     share equal to $1.55 plus an amount equal to all dividends accrued on the
     Series B Preferred Stock but unpaid at the date of such payment;

             (iii) the holders of record of the issued and outstanding shares 
     of Series C Preferred Stock shall be entitled to receive an amount per 
     share equal to $3.25 plus an amount equal to all dividends accrued on
     the Series C Preferred Stock but unpaid at the date of such payment;

              (iv) the holders of record of the issued and outstanding shares
     of Series D Preferred Stock shall be entitled to receive an amount per
     share equal to $4.30 plus an amount equal to all dividends accrued on the
     Series D Preferred Stock but unpaid at the date of such payment;

               (v)  the holders of record of the issued and outstanding shares
     of Series E/EG Preferred Stock shall be entitled to receive an amount per
     share equal to $5.00 plus an amount equal to all dividends accrued on the
     Series E/EG Preferred Stock but unpaid at the date of such payment;

              (vi) the holders of record of the issued and outstanding shares
     of Series I Preferred Stock shall be entitled to receive an amount per
     share equal to $1.25 plus an amount equal to all dividends accrued on the
     Series I Preferred Stock but unpaid at the date of such payment; and

             (vii) the holders of record of the issued and outstanding shares 
     of Class A Stock shall be entitled to receive an amount per share equal 
     to $.25 plus an amount equal to all dividends accrued on the Class A
     Stock but unpaid at the date of such payment.

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          If, upon such liquidation, dissolution or winding up of the affairs 
of the Corporation, the assets of the Corporation shall be insufficient to 
permit the payment in full to the holders of shares of the Designated 
Preferred Stock and Class A Stock of the amounts payable to them as aforesaid 
in this Section 3(a), then the holders of shares of Designated Preferred 
Stock and Class A Stock shall be treated PARI PASSU, and the entire assets of 
the Corporation legally available for distribution shall be distributed 
ratably among the holders of the shares of the Designated Preferred Stock and 
Class A Stock in proportion to the full preferential amount to which they 
otherwise would be entitled pursuant to this Section 3(a).

          (b)  SECOND PREFERENCE.  In the event of any liquidation, 
dissolution or winding up of the affairs of the Corporation, whether 
voluntary or involuntary, after the holders of shares of the Designated 
Preferred Stock and Class A Stock shall have been distributed in full the 
amounts to which they shall be entitled under Section 3(a), each holder of 
record of the issued and outstanding shares of Class A Stock shall be 
entitled to receive, out of the assets of the Corporation available for 
distribution, prior and in preference to any further distribution of any of 
the assets of the Corporation to the holders of shares of the Designated 
Preferred Stock, and prior and in preference to any distribution of any of 
the assets of the Corporation to the holders of shares of the Common Stock 
and the holders of shares of Class B Stock or otherwise, an amount equal to 
such holder's pro rata portion (based on the number of shares of Class A 
Stock held by each such holder) of the lesser of (i) the amount that is equal 
to 26% of such assets remaining available for distribution and (ii) 
$1,683,396.

          (c)  GENERAL.  

               (i)  All of the preferential amounts to be paid to the holders 
of the Designated Preferred Stock and Class A Stock pursuant to Section 3(a) 
and Section 3(b) shall be paid or set apart for payment before the payment or 
setting apart for payment of any amount for, or the distribution of any 
assets of the Corporation to, the holders of the Common Stock or Class B 
Stock or otherwise in connection with such liquidation, dissolution or 
winding up.  

               (ii) In the event that the liquidation, dissolution or winding 
up of the affairs of the Corporation is not pursuant to any of the events 
described in Section 3(e) below in which the Market Valuation of the 
Corporation as determined by such liquidation, dissolution or winding up of 
the affairs of the Corporation equals or exceeds $46,220,397, after setting 
apart or paying in full the preferential amounts aforesaid to the holders of 
record of the issued and outstanding shares of Designated Preferred Stock and 
Class A Stock as set forth in Section 3(a) and Section 3(b), the holders of 
record of the Designated Preferred Stock and Class A Stock shall be entitled 
to participate ratably in any distribution of any remaining assets of the 
Corporation to the holders of record of the issued and outstanding shares of 
Class B Stock and Common Stock, on the basis of the number of shares held by 
each such holder (for purposes of this Section 3(c)(ii), treating such shares 
of Designated Preferred Stock, Class A Stock and Class B Stock as if 
converted into shares of Common Stock pursuant to the provisions of this 
Restated Certificate of Incorporation).  For the purposes hereof, "Market 
Valuation" shall mean the aggregate value of the gross proceeds received in 
respect of such liquidation, dissolution or winding up of the Corporation 
(for the purposes of this Section 3(c)(ii), the value of any non-cash 
proceeds shall be as determined in good faith by the Board of Directors of 
the Corporation).

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          (d)  ADJUSTMENTS.  The liquidation preferences provided for herein 
with respect to any shares of any class or series of capital stock shall be 
equitably adjusted to reflect any stock dividend, stock distribution, stock 
split or reverse stock split, combination of shares, subdivision of shares or 
reclassification of shares with respect to any shares of any such class or 
series of capital stock.

          (e)  CONSOLIDATION, MERGER, SALE OF ASSETS.  For the purposes of this
Section 3, the merger or consolidation of the Corporation with or into any 
other corporation, or the sale, lease, mortgage, pledge, exchange, transfer or 
other disposition by the Corporation of all or substantially all of its assets 
shall be regarded as a liquidation, dissolution or winding up of the affairs of
the Corporation within the meaning of this Section 3.

     4.   CONVERSION RIGHTS.  The Designated Preferred Stock shall be
convertible as follows:

          (a)  OPTIONAL CONVERSION.  Subject to and upon compliance with the
provisions of this Section 4, the holder of any shares of Designated Preferred
Stock shall have the right at such holder's option, at any time or from time to
time, and without the payment of any additional consideration therefor, to
convert any of such shares of Designated Preferred Stock into fully paid and
nonassessable shares of Common Stock at the Conversion Price (as defined in
Section 4(c) below) in effect on any Conversion Date (as defined in Section 4(d)
below) upon the terms hereinafter set forth.

          (b)  AUTOMATIC CONVERSION.  Each outstanding share of Designated
Preferred Stock shall automatically be converted, without any further act of the
Corporation or its stockholders, at the Conversion Price then in effect, into
fully paid and nonassessable shares of Common Stock immediately prior to the
first closing of an underwritten public offering pursuant to an effective
registration statement filed under the Securities Act of 1933, as amended,
covering the offering and sale of shares of Common Stock, or of any equity
security that as a part of a unit includes shares of Common Stock, for the
account of the Corporation, that occurs after the effectiveness of this Restated
Certificate of Incorporation (the "Initial Public Offering").

          (c)  NUMBER OF SHARES.  Each share of 1991 Series A Preferred Stock
shall be convertible into a number of shares of Common Stock determined by
dividing (i) $1.25 by (ii) the Conversion Price for such series in effect on any
Conversion Date.  Each share of Series I Preferred Stock shall be convertible
into a number of shares of Common Stock determined by dividing (i) $1.25 by
(ii) the Conversion Price for such series in effect on any Conversion Date. 
Each share of Series B Preferred Stock shall be convertible into a number of
shares of Common Stock determined by dividing (i) $1.55 by (ii) the Conversion
Price for such series in effect on any Conversion Date.  Each share of Series C
Preferred Stock shall be convertible into a number of shares of Common Stock
determined by dividing (i) $3.25 by (ii) the Conversion Price for such series in
effect on any Conversion Date.  Each share of Series D Preferred Stock shall be
convertible into a number of shares of Common Stock determined by dividing
(i) $4.30 by (ii) the Conversion Price for such series in effect on any
Conversion Date.  Each share of Series E/EG Preferred Stock shall be convertible
into a number of shares of Common Stock determined by dividing (i) $5.00 by (ii)
the Conversion Price for such series in effect on any Conversion Date.  For the
purposes of this Section 4, the term "Conversion Price" shall initially mean,
with respect to 1991 Series A Preferred Stock, $1.25, with respect to Series I
Preferred

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Stock, $1.25, with respect to Series B Preferred Stock, $1.55, with respect 
to Series C Preferred Stock, $2.70, with respect to the Series D Preferred 
Stock, $4.30, and with respect to the Series E/EG Preferred Stock, $5.00, 
subject to adjustment as set forth in Section 4(f).  Upon conversion, no 
payment or adjustment shall be made for any dividends on the Designated 
Preferred Stock or the Common Stock issuable upon such conversion.  All 
calculations under this Section 4(c) shall be made to the nearest cent ($.01) 
or to the nearest one hundredth (1/100th) of a share, as the case may be.

          (d)  MECHANICS OF CONVERSION.  The holder of any shares of 
Designated Preferred Stock may exercise the conversion right specified in 
Section 4(a) by surrendering to the Corporation or any transfer agent of the 
Corporation the certificate or certificates for the shares to be converted, 
accompanied by written notice specifying the number of shares to be 
converted.  Upon the occurrence of any event specified in Section 4(b), the 
outstanding shares of Designated Preferred Stock shall be converted 
automatically without any further action by the holders of such shares and 
whether or not the certificates representing such shares are surrendered to 
the Corporation or its transfer agent; provided that the Corporation shall 
not be obligated to issue to any holder certificates evidencing the shares of 
Common Stock issuable upon such conversion unless certificates evidencing 
such shares of Designated Preferred Stock are delivered either to the 
Corporation or any transfer agent of the Corporation.  Conversion shall be 
deemed to have been effected on the date when delivery of notice of an 
election to convert and of certificates for shares being converted is made or 
on the date of the occurrence of any event specified in Section 4(b), as the 
case may be, and such date is referred to herein as the "Conversion Date".  
Subject to the provisions of Section 4(f)(iii), as promptly as practicable 
thereafter (and after surrender of the certificate or certificates 
representing shares of Designated Preferred Stock to the Corporation or any 
transfer agent of the Corporation in the case of conversions pursuant to 
Section 4(b)) the Corporation shall issue and deliver to or upon the written 
order of such holder a certificate or certificates for the number of full 
shares of Common Stock to which such holder is entitled and a check or cash 
with respect to any fractional interest in a share of Common Stock as 
provided in Section 4(e).  Subject to the provisions of Section 4(f)(iii), 
the person in whose name the certificate or certificates for Common Stock are 
to be issued shall be deemed to have become a holder of record of such Common 
Stock on the applicable Conversion Date.  Upon conversion of only a portion 
of the number of shares covered by a certificate representing shares of 
Designated Preferred Stock surrendered for conversion (in the case of 
conversion pursuant to Section 4(a)), the Corporation shall issue and deliver 
to or upon the written order of the holder of the certificate so surrendered 
for conversion, at the expense of the Corporation, a new certificate covering 
the number of shares of Designated Preferred Stock representing the 
unconverted portion of the certificate so surrendered.

          (e)  FRACTIONAL SHARES.  No fractional shares of Common Stock or 
scrip shall be issued upon conversion of shares of Designated Preferred 
Stock.  If more than one share of any series of Designated Preferred Stock 
shall be surrendered for conversion at any one time by the same holder, the 
number of full shares of Common Stock issuable upon conversion thereof shall 
be computed on the basis of the aggregate number of shares of such series so 
surrendered. Instead of any fractional shares of Common Stock which would 
otherwise be issuable upon conversion of any shares of Designated Preferred 
Stock, the Corporation shall pay out of funds legally available therefor a 
cash adjustment in respect of such fractional interest in an amount equal to 
that fractional interest of the then Current Market Price (as described in 
Section 4(g) below).

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          (f)  CONVERSION PRICE ADJUSTMENTS.  The Conversion Price for each 
series of Designated Preferred Stock shall be subject to adjustment from time 
to time as follows:

               (i)  STOCK DIVIDENDS, SUBDIVISIONS, RECLASSIFICATIONS OR
     COMBINATIONS.  If the Corporation shall (x) declare a dividend or make a
     distribution on its Common Stock in shares of its Common Stock, (y)
     subdivide or reclassify the outstanding shares of Common Stock into a
     greater number of shares of Common Stock or (z) combine or reclassify the
     outstanding shares of Common Stock into a smaller number of shares of
     Common Stock, the Conversion Price in effect for each series of Designated
     Preferred Stock at the time of the record date for such dividend or
     distribution or the effective date of such subdivision, combination or
     reclassification shall be adjusted to that price determined by multiplying
     the Conversion Price in effect for each series of Designated Preferred
     Stock by a fraction (x) the numerator of which shall be the total number 
     of issued and outstanding shares of Common Stock immediately prior to such
     dividend, distribution, subdivision, combination or reclassification and
     (y) the denominator of which shall be the total number of issued and
     outstanding shares of Common Stock immediately after such dividend,
     distribution, subdivision, combination or reclassification.  Successive
     adjustments in the Conversion Price shall be made whenever any event
     specified above shall occur.

              (ii) ROUNDING OF CALCULATIONS; MINIMUM ADJUSTMENT.  All 
     calculations under this Section 4(f) shall be made to the nearest cent or
     to the nearest one hundredth (1/100th) of a share, as the case may be.  
     Any provision of this Section 4 to the contrary notwithstanding, no 
     adjustment in the Conversion Price shall be made if the amount of such 
     adjustment would be less than $0.05 until the end of three years after 
     such adjustment would otherwise have been required; but any such amount 
     shall be carried forward and an adjustment with respect thereto shall be 
     made at the time of and together with any subsequent adjustment which, 
     together with such amount and any other amount or amounts so carried 
     forward, shall aggregate $0.05 or more, provided that if the events giving
     to such adjustments occur within three months of each other, then such 
     adjustments shall be calculated as if these events giving rise to them 
     had occurred simultaneously on the date of the first such event.

             (iii) TIMING OF ISSUANCE OF ADDITIONAL COMMON STOCK UPON
     CERTAIN ADJUSTMENTS.  In any case in which the provisions of this
     Section 4(f) shall require that an adjustment shall become effective
     immediately after a record date for an event, the Corporation may defer
     until the occurrence of such event (x) issuing to the holder of any share
     of Designated Preferred Stock converted after such record date and before
     the occurrence of such event the additional shares of Common Stock 
     issuable upon such conversion by reason of the adjustment required by 
     such event over and above the shares of Common Stock issuable upon such 
     conversion before giving effect to such adjustment and (y) paying to such 
     holder any amount of cash in lieu of a fractional share of Common Stock 
     pursuant to Section 4(e); provided that the Corporation upon request shall
     deliver to such holder a due bill or other appropriate instrument 
     evidencing such holder's right to receive such additional shares, and such
     cash, upon the occurrence of the event requiring such adjustment.

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               (iv) SERIES B PREFERRED STOCK, SERIES C PREFERRED STOCK, SERIES D
     PREFERRED STOCK, SERIES E PREFERRED STOCK AND SERIES EG PREFERRED STOCK. 
     The Conversion Price of the Series B Preferred Stock, the Series C
     Preferred Stock, the Series D Preferred Stock and the Series E/EG Preferred
     Stock shall be subject to adjustment from time to time as follows:

                    (A)  CERTAIN ISSUANCES OF EQUITY STOCK.  If at any time
          after the date on which the first share of Series D Preferred Stock is
          issued the Corporation shall issue any shares of Common Stock or any
          other equity security that as part of a unit or otherwise includes
          Common Stock (hereinafter, "Equity Stock") or any options or warrants
          exercisable for shares of Common Stock, any rights for Common Stock or
          any convertible securities convertible into Common Stock, other than
          Excluded Stock (as defined in Section 4(f)(iv)(B) below), without
          consideration or for a consideration per share less than the
          Conversion Price of the Series B Preferred Stock, Series C Preferred
          Stock, Series D Preferred Stock or Series E/EG Preferred Stock, as the
          case may be, in effect immediately prior to such issuance, the
          Conversion Price for such Series B Preferred Stock, Series C Preferred
          Stock, Series D Preferred Stock or Series E/EG Preferred Stock, as the
          case may be, shall be reduced to such consideration per share and the
          number of shares of Common Stock reserved for issuance upon conversion
          of such Series B Preferred Stock, Series C Preferred Stock, Series D
          Preferred Stock or Series E/EG Preferred Stock, as the case may be,
          shall concurrently be appropriately increased.  In the event any
          Equity Stock consists of an equity security that as part of a unit
          includes Common Stock, the portion of the consideration received for
          such unit that shall be attributed to the Common Stock component
          thereof shall be as determined in good faith by the Board of Directors
          of the Corporation.

          For purposes of any adjustment of any Conversion Price pursuant to
          this Section 4(f)(iv)(A), the following provisions shall be
          applicable:

                         (1)  CASH.  In the case of the issuance of shares of
               Equity Stock for cash, the amount of the consideration received
               by the Corporation shall be deemed to be the aggregate amount of
               cash received by the Corporation for such shares of Equity Stock.

                         (2)  CONSIDERATION OTHER THAN CASH.  In the case of the
               issuance of shares of Equity Stock (otherwise than upon the
               conversion of shares of capital stock or other securities of the
               Corporation) for a consideration in whole or in part other than
               cash, including securities acquired in exchange therefor (other
               than securities by their terms so exchangeable), the
               consideration other than cash shall be deemed to be the fair
               value thereof as determined in good faith by the Board of
               Directors of the Corporation, irrespective of any accounting
               treatment; provided, however, that such fair value as determined
               by the Board of Directors shall not exceed the aggregate Current
               Market Price (as described in Section 4(g) below) of the shares
               of Equity Stock being issued as of the date the Board of
               Directors authorizes the issuance of such shares.

<PAGE>
                         (3)  OPTIONS AND CONVERTIBLE SECURITIES.  In the case
               of (x) options, warrants or other rights to purchase or acquire
               Equity Stock (whether or not at the time exercisable), (y)
               securities by their terms convertible into or exchangeable for
               Equity Stock (whether or not at the time so convertible or
               exercisable), or (z) options, warrants or rights to purchase such
               convertible or exchangeable securities (whether or not at the
               time exercisable):

                              (I) the aggregate maximum number of shares of
                    Equity Stock deliverable upon exercise of such options,
                    warrants or other rights to purchase or acquire Equity Stock
                    shall be deemed to have been issued at the time such
                    options, warrants or rights were issued and for a
                    consideration equal to the consideration (determined in the
                    manner provided in Section 4(f)(iv)(A)(1) and (2) above)
                    received by the Corporation upon the issuance of such
                    options, warrants or rights plus the minimum purchase price
                    provided in such options, warrants or rights for the Equity
                    Stock covered thereby;

                             (II) the aggregate maximum number of shares of
                    Equity Stock deliverable upon conversion of or in exchange
                    for any such convertible or exchangeable securities, or upon
                    the exercise of options, warrants or other rights to
                    purchase or acquire such convertible or exchangeable
                    securities and the subsequent conversion or exchange
                    thereof, shall be deemed to have been issued at the time
                    such securities were issued or such options, warrants or
                    rights were issued and for a consideration equal to the
                    consideration, if any, received by the Corporation for any
                    such securities and related options, warrants or rights,
                    plus the minimum additional consideration, if any, to be
                    received by the Corporation upon the conversion or exchange
                    of such securities and the exercise of any related options,
                    warrants or rights (the consideration in each case to be
                    determined in the manner provided in Sections 4(f)(iv)(A)(1)
                    and (2) above); and

<PAGE>

                            (III) on any change in the number of shares of
                    Equity Stock deliverable upon exercise of any such options,
                    warrants or rights or conversion of or exchange for such
                    convertible or exchangeable securities or any change in the
                    consideration to be received by the Corporation upon such
                    exercise, conversion or exchange, including, but not limited
                    to, a change resulting from the antidilution provisions
                    thereof, the Conversion Price as then in effect shall
                    forthwith be readjusted to such Conversion Price as would
                    have been obtained had an adjustment been made upon the
                    issuance of such options, warrants or rights not exercised
                    prior to such change, or securities not converted or
                    exchanged prior to such change, on the basis of such change.

                    (B)  EXCLUDED STOCK.  "Excluded Stock" means (1) shares of
          capital stock of the Corporation issued or reserved for issuance by
          the Corporation as a stock dividend payable in shares of capital stock
          of the Corporation, or upon any subdivision or split-up of the
          outstanding shares of any shares of capital stock of the Corporation,
          or recapitalization thereof, or upon conversion of any shares of
          Designated Preferred Stock, Class A Stock or Class B Stock, (2) shares
          of capital stock issuable pursuant to those certain Stock Purchase
          Warrants of the Corporation dated February 13, 1991, March 13, 1991,
          and April 2, 1991, as any of such warrants may be amended from time to
          time, or pursuant to any stock purchase warrants issued by the
          Corporation in replacement of or exchange for any of such warrants,
          (3) shares of capital stock of the Corporation issued or issuable in
          connection with an acquisition of a business by the Corporation as a
          result of which the Corporation owns in excess of 50% of the voting
          power of such business, (4) any shares of capital stock of the
          Corporation issued or issuable to employees, officers, consultants or
          directors of the Corporation pursuant to any approval of the Board of
          Directors of the Corporation or pursuant to any employee, officer,
          consultant or director benefit plan, including any stock option plan,
          approved by the Board of Directors of the Corporation, (5) any shares
          of capital stock of the Corporation issued or issuable to (a) banks,
          savings and loan associations, equipment lessors or similar lending
          institutions in connection with such entities providing credit
          facilities or equipment financings to the Corporation or (b) any party
          to any technology transfer agreement, distribution agreement,
          marketing agreement or any other agreement similar thereto, with the
          Corporation, in connection with such party (i) licensing, assigning or
          otherwise transferring technology or rights to use technology to the
          Corporation or (ii) granting the Corporation rights to distribute any
          technology, products, services or the like, rights to market any
          technology, products, services or the like or any other rights similar
          thereto, if and only if such facility, agreement, transaction or
          arrangement included in this clause (5) and the issuance of shares in
          connection therewith is approved by the Board of Directors of the
          Corporation, (6) any stock purchase warrants issued, and any shares of
          capital stock issuable pursuant thereto, pursuant to that certain Note
          Purchase Agreement dated as of October 18, 1993, between the
          Corporation and certain investors, as any of such warrants may be
          amended from time to time, or pursuant to any stock purchase warrants
          issued

<PAGE>

          to the Corporation in replacement of or exchange for any of such 
          warrants and (7) any stock purchase warrants issued, and any shares 
          of capital stock issued pursuant thereto, pursuant to that certain 
          Series E Preferred Stock and Series EG Preferred Stock Purchase 
          Agreement made as of June 2, 1995, between the Corporation and 
          certain investors, as any of such warrants may be amended from time 
          to time, or pursuant to any stock purchase warrants issued by the
          Corporation in replacement of or exchange for any of such warrants.

          (g)  CURRENT MARKET PRICE.  The Current Market Price at any date 
shall mean, in the event the Common Stock or the Equity Stock, as the case 
may be, is publicly traded, the average of the daily closing prices per share 
of such equity security for 30 consecutive trading days ending no more than 
15 business days before such date (as adjusted for any stock dividend, split, 
combination or reclassification that took effect during such 30 trading day 
period).  The closing price for each day shall be the last reported sale 
price regular way or, in case no such reported sale takes place on such day, 
the average of the last closing bid and asked prices regular way, in either 
case on the principal national securities exchange on which such equity 
security is listed or admitted to trading, or if not listed or admitted to 
trading on any national securities exchange, the closing sale price for such 
day reported by NASDAQ, if such equity security is traded over-the-counter 
and quoted in the National Market System, or if such equity security is so 
traded, but not so quoted, the average of the closing reported bid and asked 
prices of such equity security as reported by NASDAQ or any comparable system 
or, if such equity security is not listed on NASDAQ or any comparable system, 
the average of the closing bid and asked prices as furnished by two members 
of the National Association of Securities Dealers, Inc., selected in good 
faith from time to time by the Board of Directors of the Corporation for that 
purpose.  If such equity security is not traded in such manner that the 
quotations referred to above are available for the period required hereunder, 
Current Market Price per share of such equity security shall be deemed to be 
the fair value as determined in good faith by the Board of Directors of the 
Corporation, irrespective of any accounting treatment.

          (h)  STATEMENT REGARDING ADJUSTMENTS.  Whenever the Conversion 
Price for a series of Designated Preferred Stock shall be adjusted as 
provided in Section 4(f), the Corporation shall forthwith file, at the office 
of any transfer agent for the 1991 Series A Preferred Stock, Series I 
Preferred Stock, Series B Preferred Stock, Series C Preferred Stock, Series D 
Preferred Stock, or Series E/EG Preferred Stock, as the case may be, and at 
the principal office of the Corporation, a statement showing in detail the 
method of calculation of such adjustment, the facts requiring such adjustment 
and the Conversion Price that shall be in effect after such adjustment, and 
the Corporation shall also cause a copy of such statement to be sent by mail, 
first class postage prepaid, to each holder of shares of 1991 Series A 
Preferred Stock, Series I Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock, Series E/EG Preferred Stock, as 
the case may be, at its address appearing on the Corporation's records.  Each 
such statement shall be signed by the Corporation's chief financial officer.  
Where appropriate, such copy may be given in advance and may be included as 
part of a notice required to be mailed under the provisions of Section 4(i). 

<PAGE>

           (i)  NOTICE TO HOLDERS.  In the event the Corporation shall 
propose to take any action of the type described in Section 4(f)(i), the 
Corporation shall give notice to each holder of shares of 1991 Series A 
Preferred Stock, Series I Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock or Series E/EG Preferred Stock in 
the manner set forth in Section 4(h), which notice shall specify the record 
date, if any, with respect to any such action and the approximate date on 
which such action is to take place.  Such notice shall also set forth such 
facts with respect thereto as shall be reasonably necessary to indicate the 
effect of such action (to the extent such effect may be known at the date of 
such notice) on the Conversion Price and the number, kind or class of shares 
or other securities or property which shall be deliverable upon conversion of 
shares of 1991 Series A Preferred Stock, Series I Preferred Stock, Series B 
Preferred Stock, Series C Preferred Stock, Series D Preferred Stock or Series 
E/EG Preferred Stock, as the case may be.  In the case of any action which 
would require the fixing of a record date, such notice shall be given at 
least ten days prior to the date so fixed, and in the case of all other 
action, such notice shall be given at least 15 days prior to the taking of 
such proposed action.  Failure to give such notice, or any defect therein, 
shall not affect the legality or validity of any such action.

          (j)  TREASURY STOCK.  For the purposes of this Section 4, the sale 
or other disposition of any Common Stock theretofore held in the 
Corporation's treasury shall be deemed to be an issuance thereof.

          (k)  COSTS.  The Corporation shall pay all documentary, stamp, 
transfer or other transactional taxes attributable to the issuance or 
delivery of shares of Common Stock upon conversion of any shares of 
Designated Preferred Stock; provided that the Corporation shall not be 
required to pay any taxes which may be payable in respect of any transfer 
involved in the issuance or delivery of any certificate for such shares in a 
name other than that of the holder of the shares of Designated Preferred 
Stock in respect of which such shares are being issued.

     5.   REACQUIRED SHARES.  Any shares of any series of Designated 
Preferred Stock redeemed, purchased, converted or otherwise acquired by the 
Corporation in any manner whatsoever shall not be reissued as part of such 
series and shall be retired promptly after the acquisition thereof.  All such 
shares shall upon their retirement and the filing of any certificate required 
in connection therewith pursuant to the Delaware General Corporation Law 
become authorized but unissued shares of Preferred Stock.

     6.   COPIES OF AGREEMENT, INSTRUMENTS, DOCUMENTS.  Copies of any of the 
agreements, instruments or other documents referred to in this Article A 
shall be furnished to any stockholder upon written request to the Corporation 
at its principal place of business.

B.   PREFERRED STOCK.

     The Board of Directors is authorized, subject to any limitations prescribed
by law, to provide for the issuance of the shares of Preferred Stock in series,
and by filing a certificate pursuant to the applicable law of the State of
Delaware, to establish from time to time the number of shares to be included in
each such series, and to fix the designation, powers, preferences and rights of
the shares of each such series and any qualifications, limitations or
restrictions thereof.

<PAGE>

C.   COMMON STOCK.

     1.   DIVIDENDS.  Subject to the prior and superior right of any issued 
and outstanding shares of Designated Preferred Stock, Class A Stock or Class 
B Stock as set forth in this Restated Certificate of Incorporation, the Board 
of Directors may, in its discretion, out of funds legally available for the 
payment of dividends and at such times and in such manner as determined by 
the Board of Directors, declare and pay dividends on the outstanding shares 
of Common Stock of the Corporation.

     2.   LIQUIDATION.  Subject to the provisions of this Restated 
Certificate of Incorporation, in the event of any liquidation, dissolution or 
winding up of the affairs of the Corporation, whether voluntary or 
involuntary, after payment or provision for payment of any preferential 
amount due to the holders of shares of any other class or series of stock, 
the holders of shares of Common Stock shall be entitled to receive ratably, 
based on the number of shares of Common Stock held by such holders, any 
assets of the Corporation available for distribution to holders of Common 
Stock.

     3.   VOTING RIGHTS.  The holders of shares of Common Stock shall have 
the following voting rights:

          (a)  Each share of Common Stock shall entitle the holder thereof to
     one vote on all matters submitted to a vote of the stockholders of the
     Corporation.

          (b)  Except as otherwise required by law or the provisions of this
     Restated Certificate of Incorporation, the holders of shares of Common
     Stock shall not be entitled to vote separately as a class on any matter
     submitted to a vote of the stockholders of the Corporation.

     4.   REACQUIRED SHARES.  Any shares of Common Stock purchased or 
otherwise acquired by the Corporation in any manner whatsoever that have been 
retired shall upon their retirement become authorized but unissued shares of 
Common Stock.

D.   CLASS A STOCK.

     1.   DIVIDENDS AND DISTRIBUTIONS.

          (a)  Subject to the prior and superior right of any issued and 
outstanding shares of Designated Preferred Stock as set forth in this 
Restated Certificate of Incorporation, the holders of shares of Class A Stock 
shall be entitled to receive, when, as and if declared by the Board of 
Directors of the Corporation out of funds legally available for the purpose, 
dividends equal to the product of:

               (i)  the aggregate per share amount of all dividends declared on
     the Common Stock since the immediately preceding payment of dividends on
     the Class A Stock; and

<PAGE>

              (ii) the number of shares of Common Stock into which a share of
     Class A Stock would be convertible on the date on which the dividend is to
     be paid (assuming for the purpose of this Section 1(a) only that such share
     was then convertible pursuant to the provisions of Section 4(a) below);

and the Corporation shall declare a cash dividend on the Class A Stock as 
provided in this Section 1(a) immediately after it declares a cash dividend 
on the Common Stock, and no dividends shall be declared on the Common Stock 
unless the Corporation has funds legally available for the payment of such 
dividend on the Common Stock and for the payment of the dividends 
contemplated by this Section 1 on the Class A Stock.  The Board of Directors 
of the Corporation may fix a record date for the determination of holders of 
shares of Class A Stock entitled to receive payment of a dividend declared 
thereon, which record date shall be no more than 60 days prior to the date 
fixed for the payment thereof.

          (b)  Subject to the prior and superior right of any issued and 
outstanding shares of Designated Preferred Stock as set forth in this 
Restated Certificate of Incorporation, the holders of shares of Class A Stock 
shall be entitled to receive any non-cash dividend or other distribution 
(including, without limitation, any distribution of other or additional stock 
or other securities or property or rights or warrants to subscribe for or 
purchase Common Stock or other securities of the Corporation or any of its 
subsidiaries by way of dividend or spin-off, issuance of rights, or 
reclassification, recapitalization or similar corporate rearrangement) which 
the Corporation shall at any time or from time to time declare, order, pay or 
make on the Common Stock, other than a dividend payable in shares of Common 
Stock or a subdivision of the outstanding shares of Common Stock (by 
reclassification or otherwise), and the Corporation at the same time it 
declares, orders, pays or makes such dividend or distribution on the Common 
Stock shall declare, order, make and pay such dividend or distribution on the 
Class A Stock, in an amount per share of Class A Stock equal to the product 
of:

               (i)  the aggregate per share amount of such dividend or
     distribution declared, ordered, paid or made on the Common Stock; and

               (ii) the number of shares of Common Stock into which a share of
     Class A Stock would be convertible on the date on which such dividend or
     distribution is to be paid or made (assuming for the purpose of this
     Section 1(b) only that such share was then convertible pursuant to the
     provisions of Section 4(a) below).

     2.   VOTING RIGHTS.  The holders of shares of Class A Stock shall have the
following voting rights:

          (a)  Each share of Class A Stock shall entitle the holder thereof to
     25% of one vote on all matters submitted to a vote of the stockholders of
     the Corporation.

          (b)  Except as otherwise required by law or the provisions of this
     Restated Certificate of Incorporation, the holders of shares of Class A
     Stock shall not be entitled to vote separately as a class on any matter
     submitted to a vote of the stockholders of the Corporation.

<PAGE>

     3.   LIQUIDATION.  In the event of any liquidation, dissolution or 
winding up of the affairs of the Corporation, whether voluntary or 
involuntary, the Class A Stock shall have the preferences and relative, 
participating, optional or other special rights, and the qualifications, 
limitations or restrictions thereof, set forth in Section 3 of Part A of this 
Fourth Article.

     4.   CONVERSION.  The Class A Stock shall be convertible into Common 
Stock as follows:

          (a)  AUTOMATIC CONVERSION.  Each outstanding share of Class A Stock
     shall automatically be converted, without any further act of the
     Corporation or its stockholders, into one fully paid and nonassessable
     share of Common Stock (i) immediately prior to the closing of the Initial
     Public Offering or (ii) immediately prior to the closing of any
     liquidation, dissolution or winding up of the affairs of the Corporation
     pursuant to any of the events described in Section 3(e) of Part A of the
     Fourth Article of this Restated Certificate of Incorporation in which the
     Market Valuation (as defined in Section 3(c)(ii) of Part A of the Fourth
     Article of this Restated Certificate of Incorporation) of the Corporation
     as determined by such liquidation, dissolution or winding up of the 
     affairs of the Corporation equals or exceeds $46,220,397.

          (b)  MECHANICS OF CONVERSION.  Upon the occurrence of any event
     specified in Section 4(a), the outstanding shares of Class A Stock shall 
     be converted automatically without any further action by the holders of 
     such shares and whether or not the certificates representing such shares 
     are surrendered to the Corporation or its transfer agent; provided that 
     the Corporation shall not be obligated to issue to any holder certificates
     evidencing the shares of Common Stock issuable upon such conversion unless
     certificates evidencing the shares of Class A Stock are delivered to 
     either the Corporation or any transfer agent of the Corporation.  
     Conversion shall be deemed to have been effected on the date of the 
     occurrence of the event specified in Section 4(a), and such date is 
     referred to herein as the "Class A Conversion Date".  As promptly as 
     practicable after surrender of the certificate or certificates 
     representing shares of Class A Stock to the Corporation or any transfer 
     agent of the Corporation, the Corporation shall issue and deliver to or 
     upon the written order of such holder a certificate or certificates for 
     the number of shares of Common Stock to which such holder is entitled.
     The person in whose name the certificate or certificates for Common Stock
     are to be issued shall be deemed to have become a holder of record of 
     such Common Stock on the applicable Class A Conversion Date.

<PAGE>

          (c)  CONVERSION RATIO ADJUSTMENTS.  If the Corporation shall (x)
     declare a dividend or make a distribution on its Common Stock in shares of
     its Common Stock, (y) subdivide or reclassify the outstanding shares of
     Common Stock into a greater number of shares of Common Stock or (z) combine
     or reclassify the outstanding Common Stock into a smaller number of shares
     of Common Stock, the conversion ratio in effect for Class A Stock at the
     time of the record date for such dividend or distribution or the effective
     date of such subdivision, combination or reclassification shall be
     appropriately adjusted so that the holder of any shares of Class A Stock
     surrendered for conversion after such date shall be entitled to receive the
     number of shares of Common Stock which such holder would have received had
     such Class A Stock been converted immediately prior to such date. 
     Successive adjustments in the conversion ratio for the Class A Stock shall
     be made whenever any event specified in this Section 4(c) shall occur.

          (d)  COSTS.  The Corporation shall pay all documentary, stamp,
     transfer or other transactional taxes attributable to the issuance or
     delivery of shares of Common Stock upon conversion of any shares of Class A
     Stock; provided that the Corporation shall not be required to pay any taxes
     which may be payable in respect of any transfer involved in the issuance or
     delivery of any certificate for such shares in a name other than that of
     the holder of the shares of Class A Stock in respect of which such shares
     are being issued.

     5.   REACQUIRED SHARES.  Any shares of Class A Stock redeemed, purchased or
otherwise acquired by the Corporation in any manner whatsoever (other than upon
conversion into Common Stock) that have been retired shall upon their retirement
become authorized but unissued shares of Class A Stock.  Any shares of Class A
Stock converted into Common Stock shall be retired promptly after such
conversion and such shares shall not be reissued.

E.   CLASS B STOCK.

     1.   DIVIDENDS AND DISTRIBUTIONS.

          (a)  Subject to the prior and superior right of any issued and
outstanding shares of Designated Preferred Stock as set forth in this
Certificate, the holders of shares of Class B Stock shall be entitled to
receive, when, as and if declared by the Board of Directors out of funds legally
available for the purpose, dividends equal to the product of:

               (i)  the aggregate per share amount of all dividends declared on
     the Common Stock since the immediately preceding payment of dividends on
     the Class B Stock; and

              (ii) the number of shares of Common Stock into which a share of
     Class B Stock is convertible on the date which the dividend is to be paid;

<PAGE>

and the Corporation shall declare a cash dividend on the Class B Stock as 
provided in this Section 1(a) immediately after it declares a cash dividend 
on the Common Stock, and no dividends shall be declared on the Common Stock 
unless the Corporation has funds legally available for the payment of such 
dividend on the Common Stock and for the payment of the dividends 
contemplated by this Section 1 on the Class B Stock.  The Board of Directors 
may fix a record date for the determination of holders of shares of Class B 
Stock entitled to receive payment of a dividend declared thereon, which 
record date shall be no more than 60 days prior to the date fixed for the 
payment thereof.

          (b)  Subject to the prior and superior right of any issued and 
outstanding shares of Designated Preferred Stock as set forth in this 
Restated Certificate of Incorporation, the holders of shares of Class B Stock 
shall be entitled to receive any non-cash dividend or other distribution 
(including, without limitation, any distribution of other or additional stock 
or other securities or property or rights or warrants to subscribe for or 
purchase Common Stock or other securities of the Corporation or any of its 
subsidiaries by way of dividend or spin-off, issuance of rights, or 
reclassification, recapitalization or similar corporate rearrangement) which 
the Corporation shall at any time or from time to time declare, order, pay or 
make on the Common Stock, other than a dividend payable in shares of Common 
Stock or a subdivision of the outstanding shares of Common Stock (by 
reclassification or otherwise), and the Corporation at the same time it 
declares, orders, pays or makes such dividend or distribution on the Common 
Stock shall declare, order, make and pay such dividend or distribution on the 
Class B Stock, in an amount per share of Class B Stock equal to the product 
of:

               (i)  the aggregate per share amount of such dividend or
     distribution declared, ordered, paid or made on the Common Stock; and

               (ii) the number of shares of Common Stock into which a share of
     Class B Stock is convertible on the date on which such dividend or
     distribution is to be paid or made.

     2.   VOTING RIGHTS.  The holders of shares of Class B Stock shall have the
following voting rights:

          (a)  Each share of Class B Stock shall entitle the holder thereof to
     25% of one vote on all matters submitted to a vote of the stockholders of
     the Corporation.

          (b)  Except as otherwise required by law or the provisions of this
     Restated Certificate of Incorporation, the holders of shares of Class B
     Stock shall not be entitled to vote separately as a class on any matter
     submitted to a vote of the stockholders of the Corporation.

     3.   LIQUIDATION.  Subject to the provisions of this Restated Certificate
of Incorporation, the Class B Stock shall rank on a parity with the Common Stock
in respect of distributions upon any liquidation, dissolution or winding up of
the affairs of the Corporation, whether voluntary or involuntary.

<PAGE>

     4.   CONVERSION.  The Class B Stock shall be convertible into Common Stock
as follows:

          (a)  AUTOMATIC CONVERSION.  Each outstanding share of Class B Stock
     shall automatically be converted, without any further act of the
     Corporation or its stockholders, into one fully paid and nonassessable
     share of Common Stock immediately prior to the closing of the Initial
     Public Offering.

          (b)  MECHANICS OF CONVERSION.  Upon the occurrence of the event
     specified in Section 4(a), the outstanding shares of Class B Stock shall 
     be converted automatically without any further action by the holders of 
     such shares and whether or not the certificates representing such shares 
     are surrendered to the Corporation or its transfer agent; provided that 
     the Corporation shall not be obligated to issue to any holder certificates
     evidencing the shares of Common Stock issuable upon such conversion unless
     certificates evidencing the shares of Class B Stock are delivered to either
     the Corporation or any transfer agent of the Corporation.  Conversion shall
     be deemed to have been effected on the date of the occurrence of the event
     specified in Section 4(a), and such date is referred to herein as the
     "Class B Conversion Date".  As promptly as practicable after surrender of
     the certificate or certificates representing shares of Class B Stock to the
     Corporation or any transfer agent of the Corporation, the Corporation shall
     issue and deliver to or upon the written order of such holder a certificate
     or certificates for the number of shares of Common Stock to which such
     holder is entitled.  The person in whose name the certificate or
     certificates for Common Stock are to be issued shall be deemed to have
     become a holder of record of such Common Stock on the applicable Class B
     Conversion Date.

          (c)  CONVERSION RATIO ADJUSTMENTS.  If the Corporation shall (x)
     declare a dividend or make a distribution on its Common Stock in shares of
     its Common Stock, (y) subdivide or reclassify the outstanding shares of
     Common Stock into a greater number of shares of Common Stock or (z) combine
     or reclassify the outstanding Common Stock into a smaller number of shares
     of Common Stock, the conversion ratio in effect for Class B Stock at the
     time of the record date for such dividend or distribution or the effective
     date of such subdivision, combination or reclassification shall be
     appropriately adjusted so that the holder of any shares of Class B Stock
     surrendered for conversion after such date shall be entitled to receive the
     number of shares of Common Stock which such holder would have received had
     such Class B Stock been converted immediately prior to such date. 
     Successive adjustments in the conversion ratio for the Class B Stock shall
     be made whenever any event specified in this Section 4(c) shall occur.

          (d)  COSTS.  The Corporation shall pay all documentary, stamp,
     transfer or other transactional taxes attributable to the issuance or
     delivery of shares of Common Stock upon conversion of any shares of Class B
     Stock; provided that the Corporation shall not be required to pay any taxes
     which may be payable in respect of any transfer involved in the issuance or
     delivery of any certificate for such shares in a name other than that of
     the holder of the shares of Class B Stock in respect of which such shares
     are being issued.

<PAGE>

     5.   REACQUIRED SHARES.  Any shares of Class B Stock redeemed, 
purchased, converted or otherwise acquired by the Corporation in any manner 
whatsoever shall be retired promptly after the acquisition thereof and shall 
not be reissued.

F.   NUMBER OF AUTHORIZED SHARES.

     The number of authorized shares of any class of capital stock of the 
Corporation may be increased or decreased (but not below the number of shares 
thereof then outstanding) by the affirmative vote of the holders of a 
majority of the shares of capital stock of the Corporation entitled to vote 
on matters submitted to a vote of the stockholders of the Corporation, and no 
class vote shall be required in connection therewith.

     FIFTH:

A.   Subject to the rights of the holders of any series of Preferred Stock to
     elect additional directors under specified circumstances, the number of
     directors shall be fixed from time to time exclusively by the Board of
     Directors pursuant to a resolution adopted by a majority of the Whole
     Board.  For purposes of this Restated Certificate of Incorporation, the
     term "Whole Board" shall mean the total number of authorized directors
     whether or not there exist any vacancies in previously authorized
     directorships.  Effective upon the effectiveness of this Restated
     Certificate of Incorporation, the directors, other than those who may be
     elected by the holders of any series of Preferred Stock under specified
     circumstances, shall be divided into three classes, with the term of 
     office of the first class to expire at the Corporation's first annual 
     meeting of stockholders held after the election of directors to such 
     classes, the term of office of the second class to expire at the 
     Corporation's second annual meeting of stockholders held thereafter 
     and the term of office of the third class to expire at the Corporation's 
     third annual meeting of stockholders held thereafter.  At each annual 
     meeting of stockholders, directors elected to succeed those directors 
     whose terms expire shall be elected for a term of office to expire at the
     third succeeding annual meeting of stockholders held after their election.
     During the period commencing on the effectiveness of this Restated 
     Certificate of Incorporation and terminating immediately prior to the 
     closing of the Initial Public Offering, directors may be removed with or 
     without cause.

B.   Subject to the rights of the holders of any series of Preferred Stock then
     outstanding, newly created directorships resulting from any increase in the
     authorized number of directors or any vacancies in the Board of Directors
     resulting from death, resignation, retirement, disqualification, removal
     from office or other cause shall, unless otherwise provided by law or by
     resolution of the Board of Directors, be filled only by a majority vote of
     the directors then in office, though less than a quorum, and directors so
     chosen shall hold office for a term expiring at the annual meeting of
     stockholders at which the term of office of the class to which they have
     been chosen expires.  No decrease in the authorized number of directors
     shall shorten the term of any incumbent director.

C.   Elections of directors need not be by written ballot unless the bylaws of
     the Corporation shall so provide.

<PAGE>

     SIXTH:  

A.   A director of the Corporation shall not be personally liable to the
     Corporation or its stockholders for monetary damages for breach of
     fiduciary duty as a director, except for liability (i) for any breach of
     the director's duty of loyalty to the Corporation or its stockholders, (ii)
     for acts or omissions not in good faith or which involve intentional
     misconduct or a knowing violation of law, (iii) under Section 174 of the
     Delaware General Corporation Law, or (iv) for any transaction from which
     the director derived an improper personal benefit.  If the Delaware General
     Corporation Law hereafter is 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 personal
     liability provided herein, shall be limited to the fullest extent permitted
     by the amended Delaware General Corporation Law.  Any repeal or
     modification of this paragraph by the stockholders of the Corporation shall
     be prospective only, and shall not adversely affect any limitation on the
     personal liability of a director of the Corporation existing at the time of
     such repeal or modification.  

B.   The Corporation shall indemnify any director who, as the result of his
     acting as a director of the Corporation, was or is a party or is threatened
     to be made a party to any threatened, pending or contemplated action, suit
     or proceeding, whether civil, criminal, administrative or investigative, to
     the full extent permitted by Delaware law.

     SEVENTH:  In furtherance of, and not in limitation of, the powers 
conferred by statute, the Board of Directors is expressly authorized to 
adopt, amend or repeal the bylaws of the Corporation, or adopt new bylaws, 
without any action on the part of the stockholders.

     EIGHTH:  Without the affirmative vote or the prior written consent of 
the holders in interest of at least a majority of the shares of Series B 
Preferred Stock at any time issued and outstanding (treated as if converted 
into shares of Common Stock and including any shares of Common Stock then 
held by such holders into which shares of Series B Preferred Stock have been 
converted), the Corporation shall not and shall not permit its subsidiaries 
(if any) to, together or alone, enter into any transaction of merger, 
consolidation or reorganization, or dissolve, wind up or liquidate or convey, 
sell, lease, exchange, transfer or otherwise dispose of in any transaction or 
related series of transactions any of its respective properties, business or 
assets having in the aggregate a fair market value of more than 10% of the 
book value of the Corporation's assets on a consolidated basis or which 
generate more than 10% of the Corporation's revenues (during the immediately 
preceding 12 months) on a consolidated basis (other than pursuant to the 
pledge of assets by the Corporation as collateral pursuant to any agreement 
with any bank, savings and loan association, equipment lessor or similar 
lending institution in connection with such entities providing credit 
facilities or equipment financings to the Corporation pursuant to any 
approval of the Board of Directors of the Corporation), or permit any 
subsidiary of the Corporation whose property, business, assets or revenues 
satisfy any of the foregoing tests to enter into any transaction of merger, 
consolidation or reorganization; provided, however, that notwithstanding the 
foregoing, (i) the affirmative vote or the prior written consent of the 
holders in interest of at least a majority of the aggregate number of shares 
of 1991 Series A Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock and Series E/EG Preferred Stock at 
any time issued and outstanding (treated as if converted into shares of 
Common Stock and including any shares of Common Stock then held by such 
holders into which shares of 1991 Series A Preferred Stock, Series B 
Preferred Stock, Series C Preferred Stock, Series D Preferred

<PAGE>

Stock or Series E/EG Preferred Stock have been converted), whether or not 
such number includes the holders in interest of at least a majority of the 
shares of Series B Preferred Stock then issued and outstanding (treated as if 
converted into shares of Common Stock and including any shares of Common 
Stock then held by such holders into which shares of Series B Preferred Stock 
have been converted), shall be required and shall be sufficient for any of 
the foregoing actions if as a result upon the closing of such action each of 
the holders of shares of Series B Preferred Stock then issued and outstanding 
receives proceeds (consisting of cash and/or publicly traded securities; for 
purposes of this Eighth Article, the value of any publicly traded securities 
shall be as determined in good faith by the Board of Directors of the 
Corporation) per share equal to at least $4.65, as equitably adjusted to 
reflect any stock dividend, stock distribution, stock split or reverse stock 
split, combination of shares, subdivision of shares or reclassification of 
shares, (ii) any subsidiary of the Corporation may be merged or consolidated 
with or into the Corporation or with or into any one or more wholly owned 
subsidiaries of the Corporation and (iii) any subsidiary of the Corporation 
may sell, lease, exchange, transfer or otherwise dispose of any or all of its 
assets (upon voluntary liquidation or otherwise) to the Corporation or a 
wholly owned subsidiary of the Corporation.

     NINTH:  Without the affirmative vote or the prior written consent of the 
holders in interest of at least a majority of the shares of Series C 
Preferred Stock at any time issued and outstanding (treated as if converted 
into shares of Common Stock and including any shares of Common Stock then 
held by such holders into which shares of Series C Preferred Stock have been 
converted), the Corporation shall not and shall not permit its subsidiaries 
(if any) to, together or alone, enter into any transaction of merger, 
consolidation or reorganization, or dissolve, wind up or liquidate or convey, 
sell, lease, exchange, transfer or otherwise dispose of in any transaction or 
related series of transactions any of its respective properties, business or 
assets having in the aggregate a fair market value of more than 10% of the 
book value of the Corporation's assets on a consolidated basis or which 
generate more than 10% of the Corporation's revenues (during the immediately 
preceding 12 months) on a consolidated basis (other than pursuant to the 
pledge of assets by the Corporation as collateral pursuant to any agreement 
with any bank, savings and loan association, equipment lessor or similar 
lending institution in connection with such entities providing credit 
facilities or equipment financings to the Corporation pursuant to any 
approval of the Board of Directors of the Corporation), or permit any 
subsidiary of the Corporation whose property, business, assets or revenues 
satisfy any of the foregoing tests to enter into any transaction of merger, 
consolidation or reorganization; provided, however, that notwithstanding the 
foregoing, (i) the affirmative vote or the prior written consent of the 
holders in interest of at least a majority of the aggregate number of shares 
of 1991 Series A Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock and Series E/EG Preferred Stock at 
any time issued and outstanding (treated as if converted into shares of 
Common Stock and including any shares of Common Stock then held by such 
holders into which shares of 1991 Series A Preferred Stock, Series B 
Preferred Stock, Series C Preferred Stock, Series D Preferred Stock or Series 
E/EG Preferred Stock have been converted), whether or not such number 
includes the holders in interest of at least a majority of the shares of 
Series C Preferred Stock then issued and outstanding (treated as if converted 
into shares of Common Stock and including any shares of Common Stock then 
held by such holders into which shares of Series C Preferred Stock have been 
converted), shall be required and shall be sufficient for any of the 
foregoing actions if as a result upon the closing of such action each of the 
holders of shares of Series C Preferred Stock then issued and outstanding 
receives proceeds (consisting of cash and/or publicly traded securities; for 
purposes of this Ninth Article, the value of any publicly traded securities 

<PAGE>

shall be as determined in good faith by the Board of Directors of the 
Corporation) per share of such Series C Preferred Stock (treated as if 
converted into shares of Common Stock and including any shares of Common 
Stock then held by such holders into which shares of Series C Preferred Stock 
have been converted) equal to at least $9.75, as equitably adjusted to 
reflect any stock dividend, stock distribution, stock split or reverse stock 
split, combination of shares, subdivision of shares or reclassification of 
shares, (ii) any subsidiary of the Corporation may be merged or consolidated 
with or into the Corporation or with or into any one or more wholly owned 
subsidiaries of the Corporation and (iii) any subsidiary of the Corporation 
may sell, lease, exchange, transfer or otherwise dispose of any or all of its 
assets (upon voluntary liquidation or otherwise) to the Corporation or a 
wholly owned subsidiary of the Corporation.

     TENTH:  Without the affirmative vote or the prior written consent of the 
holders in interest of at least a majority of the shares of Series D 
Preferred Stock at any time issued and outstanding (treated as if converted 
into shares of Common Stock and including any shares of Common Stock then 
held by such holders into which shares of Series D Preferred Stock have been 
converted), the Corporation shall not and shall not permit its subsidiaries 
(if any) to, together or alone, enter into any transaction of merger, 
consolidation or reorganization, or dissolve, wind up or liquidate or convey, 
sell, lease, exchange, transfer or otherwise dispose of in any transaction or 
related series of transactions any of its respective properties, business or 
assets having in the aggregate a fair market value of more than 10% of the 
book value of the Corporation's assets on a consolidated basis or which 
generate more than 10% of the Corporation's revenues (during the immediately 
preceding 12 months) on a consolidated basis (other than pursuant to the 
pledge of assets by the Corporation as collateral pursuant to any agreement 
with any bank, savings and loan association, equipment lessor or similar 
lending institution in connection with such entities providing credit 
facilities or equipment financings to the Corporation pursuant to any 
approval of the Board of Directors of the Corporation), or permit any 
subsidiary of the Corporation whose property, business, assets or revenues 
satisfy any of the foregoing tests to enter into any transaction of merger, 
consolidation or reorganization; provided, however, that notwithstanding the 
foregoing, (i) the affirmative vote or the prior written consent of the 
holders in interest of at least a majority of the aggregate number of shares 
of 1991 Series A Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock and Series E/EG Preferred Stock at 
any time issued and outstanding (treated as if converted into shares of 
Common Stock and including any shares of Common Stock then held by such 
holders into which shares of 1991 Series A Preferred Stock, Series B 
Preferred Stock, Series C Preferred Stock, Series D Preferred Stock or Series 
E/EG Preferred Stock have been converted), whether or not such number 
includes the holders in interest of at least a majority of the shares of 
Series D Preferred Stock then issued and outstanding (treated as if converted 
into shares of Common Stock and including any shares of Common Stock then 
held by such holders into which shares of Series D Preferred Stock have been 
converted), shall be required and shall be sufficient for any of the 
foregoing actions if as a result upon the closing of such action each of the 
holders of shares of Series D Preferred Stock then issued and outstanding 
receives proceeds (consisting of cash and/or publicly traded securities; for 
purposes of this Tenth Article, the value of any publicly traded securities 
shall be as determined in good faith by the Board of Directors of the 
Corporation) per share equal to at least $10.00, as equitably adjusted to 
reflect any stock dividend, stock distribution, stock split or reverse stock 
split, combination of shares, subdivision of shares or reclassification of <PAGE>
 

<PAGE>

shares, (ii) any subsidiary of the Corporation may be merged or consolidated 
with or into the Corporation or with or into any one or more wholly owned 
subsidiaries of the Corporation and (iii) any subsidiary of the Corporation 
may sell, lease, exchange, transfer or otherwise dispose of any or all of its 
assets (upon voluntary liquidation or otherwise) to the Corporation or a 
wholly owned subsidiary of the Corporation.

     ELEVENTH:  Without the affirmative vote or the prior written consent of 
the holders in interest of at least a majority of the aggregate number of 
shares of Series E/EG Preferred Stock at any time issued and outstanding 
(treated as if converted into shares of Common Stock and including any shares 
of Common Stock then held by such holders into which shares of Series E/EG 
Preferred Stock have been converted), the Corporation shall not and shall not 
permit its subsidiaries (if any) to, together or alone, enter into any 
transaction of merger, consolidation or reorganization, or dissolve, wind up 
or liquidate or convey, sell, lease, exchange, transfer or otherwise dispose 
of in any transaction or related series of transactions any of its respective 
properties, business or assets having in the aggregate a fair market value of 
more than 10% of the book value of the Corporation's assets on a consolidated 
basis or which generate more than 10% of the Corporation's revenues (during 
the immediately preceding 12 months) on a consolidated basis (other than 
pursuant to the pledge of assets by the Corporation as collateral pursuant to 
any agreement with any bank, savings and loan association, equipment lessor 
or similar lending institution in connection with such entities providing 
credit facilities or equipment financings to the Corporation pursuant to any 
approval of the Board of Directors of the Corporation), or permit any 
subsidiary of the Corporation whose property, business, assets or revenues 
satisfy any of the foregoing tests to enter into any transaction of merger, 
consolidation or reorganization; provided, however, that notwithstanding the 
foregoing, (i) the affirmative vote or the prior written consent of the 
holders in interest of at least a majority of the aggregate number of shares 
of 1991 Series A Preferred Stock, Series B Preferred Stock, Series C 
Preferred Stock, Series D Preferred Stock and Series E/EG Preferred Stock at 
any time issued and outstanding (treated as if converted into shares of 
Common Stock and including any shares of Common Stock then held by such 
holders into which shares of 1991 Series A Preferred Stock, Series B 
Preferred Stock, Series C Preferred Stock, Series D Preferred Stock or Series 
E/EG Preferred Stock have been converted), whether or not such number 
includes the holders in interest of at least a majority of the shares of 
Series E/EG Preferred Stock then issued and outstanding (treated as if 
converted into shares of Common Stock and including any shares of Common 
Stock then held by such holders into which shares of Series E/EG Preferred 
Stock have been converted), shall be required and shall be sufficient for any 
of the foregoing actions if as a result upon the closing of such action each 
of the holders of shares of Series E/EG Preferred Stock then issued and 
outstanding receives proceeds (consisting of cash and/or publicly traded 
securities; for purposes of this Eleventh Article, the value of any publicly 
traded securities shall be as determined in good faith by the Board of 
Directors of the Corporation) per share equal to at least $10.00, as 
equitably adjusted to reflect any stock dividend, stock distribution, stock 
split or reverse stock split, combination of shares, subdivision of shares or 
reclassification of shares, (ii) any subsidiary of the Corporation may be 
merged or consolidated with or into the Corporation or with or into any one 
or more wholly owned subsidiaries of the Corporation and (iii) any subsidiary 
of the Corporation may sell, lease, exchange, transfer or otherwise dispose 
of any or all of its assets (upon voluntary liquidation or otherwise) to the 
Corporation or a wholly owned subsidiary of the Corporation.

<PAGE>

      IN WITNESS WHEREOF, the Corporation has caused this Restated 
Certificate of Incorporation, which restates and integrates and also amends 
the Corporation's Restated Certificate of Incorporation, after having been 
duly adopted by the Corporation in accordance with the provisions of Sections 
242 and 245 of the Delaware General Corporation Law, and written consent 
having been given in accordance with and written notice having been given as 
provided in Section 228 of the Delaware General Corporation Law, to be signed 
by its duly authorized officer on this 28 day of March, 1996.

                                       UROCOR, INC.



                                       By  /s/William A. Hagstrom
                                           ------------------------------------
                                              William A. Hagstrom, President

<PAGE>


                         CERTIFICATE OF DESIGNATION, POWERS,
                                PREFERENCES AND RIGHTS

                                          of

                               SERIES I PREFERRED STOCK

                                          of

                                     UROCOR, INC.

                Pursuant to Section 151 of the General Corporation Law
                               of the State of Delaware


          The undersigned, Socrates H. Choumbakos, Senior Vice President, 
Corporate Planning and Development and Secretary of UroCor, Inc., a Delaware 
corporation (the "Company"), hereby certifies that pursuant to authority 
granted to and vested in the Board of Directors of the Company by the 
provisions of the Restated Certificate of Incorporation of the Company, the 
Board of Directors of the Company has duly adopted the following resolutions 
creating a series of Preferred Stock designated as the Series I  Preferred 
Stock:

          "RESOLVED, that pursuant to Article Fourth of the Restated 
Certificate of Incorporation of UroCor, Inc., a Delaware corporation (the 
"Corporation"), which (a) authorizes the Corporation to issue 6,000,000 
shares of Preferred Stock, par value $.01 per share ("Preferred Stock"), none 
of which are issued and outstanding at the date hereof, and (b) expressly 
vests in the Board of Directors of the Corporation (the "Board"), subject to 
the limitations prescribed by law and the provisions of said Article Fourth, 
the authority to provide by resolution or resolutions for the issuance of 
shares of Preferred Stock in series and, by filing a certificate pursuant to 
the General Corporation Law of the State of Delaware, to establish from time 
to time the number of shares to be included in each of such series and to fix 
the designation, powers, preferences and rights of the shares of each of such 
series, or of particular holders thereof, the Board hereby fixes the powers, 
preferences and rights of the shares of a series of Preferred Stock and the 
qualifications, limitations and restrictions thereof, as follows:

          Section 1.  DESIGNATION AND AMOUNT.  The shares of such series 
shall be designated "Series I  Preferred Stock", and the number of shares 
constituting the Series I Preferred Stock shall initially be 50,000.  The 
number of shares of Series I  Preferred Stock may be increased or decreased 
from time to time by resolution of the Board, PROVIDED that no such decrease 
shall reduce the number of shares of Series I Preferred Stock to less than 
the sum of (a) the number of shares of Series I Preferred Stock then 
outstanding, (b) the number of shares of Series I Preferred Stock that the 
Corporation is obligated to issue upon the exercise of then outstanding 
rights, options or warrants and (c) the number of shares of Series I  
Preferred Stock that the Corporation is obligated to issue upon the 
conversion of then outstanding convertible securities.

<PAGE>

           Section 2.  DIVIDENDS AND DISTRIBUTIONS.

          (a)  Subject to the rights of holders of shares of any series of 
Preferred Stock that  ranks prior to the Series I  Preferred Stock with 
respect to dividends, the holders of shares of Series I Preferred Stock, in 
preference to the rights of holders of shares of Common Stock, par value $.01 
per share ("Common Stock"), of the Corporation with respect to dividends, and 
in preference to the rights of holders of shares of any series of Preferred 
Stock that ranks junior to the Series I  Preferred Stock with respect to 
dividends, shall be entitled to receive, when, as and if declared by the 
Board out of funds legally available for that purpose, quarterly dividends, 
which shall be payable in cash except as hereinafter provided, on the first 
day of January, April, July and October in each year during which a share or 
fraction of a share of Series I Preferred Stock is outstanding (each such 
date being referred to herein as a "Quarterly Dividend Payment Date"), 
commencing on the first Quarterly Dividend Payment Date after the first 
issuance of a share or fraction of a share of Series I  Preferred Stock, each 
such dividend to be in an amount per share (rounded to the nearest cent) 
equal to:

           (i)  subject to the provision for adjustment set forth in 
      the next succeeding sentence,

               (A)  1,000 times the aggregate per share amount of all cash
          dividends declared on the Common Stock after the immediately preceding
          Quarterly Dividend Payment Date or, with respect to the first
          Quarterly Dividend Payment Date, after the first issuance of any share
          or fraction of a share of Series I  Preferred Stock, plus

               (B)  1,000 times the aggregate per share amount, which shall be
          payable in kind, of all non-cash dividends or other distributions
          (other than (x) a dividend on the Common Stock that is payable in
          shares of Common Stock or (y) a distribution solely on account of a
          reclassification of, or other split-up, division or combination of
          shares of, Common Stock) declared on the Common Stock after the
          immediately preceding Quarterly Dividend Payment Date or, with respect
          to the first Quarterly Dividend Payment Date, after the first issuance
          of any share or fraction of a share of Series I  Preferred Stock; or

          (ii) if no dividend or other distribution (other than (x) a dividend
     on the Common Stock that is payable in shares of Common Stock or (y) a
     distribution solely on account of a reclassification of, or other split-up,
     division or combination of shares of, Common Stock) shall have been
     declared on the Common Stock after the immediately preceding Quarterly
     Dividend Payment Date or, with respect to the first Quarterly Dividend
     Payment Date, after the first issuance of any share or fraction of a share
     of Series I  Preferred Stock, $1.00.

<PAGE>

In the event that the Corporation shall at any time after August 27, 1998, 
(1) declare a dividend on the Common Stock that is payable in shares of 
Common Stock, (2) reclassify the Common Stock or (3) otherwise effect a 
split-up, division or combination of shares of Common Stock, then in each 
such case the amount per share to which holders of shares of Series I  
Preferred Stock were entitled immediately prior to such event under Section 
2(a)(i) shall be adjusted by multiplying such amount by a fraction, the 
numerator of which shall be the number of shares of Common Stock that are 
outstanding immediately after such event and the denominator of which shall 
be the number of shares of Common Stock that were outstanding immediately 
prior to such event.

     (b)  Immediately after the Board declares a dividend or other 
distribution on the Common Stock (other than (x) a dividend on the Common 
Stock that is payable in shares of Common Stock or (y) a distribution solely 
on account of a reclassification of, or other split-up, division or 
combination of shares of, Common Stock), if any share or fraction of a share 
of Series I  Preferred Stock is then outstanding, the Board shall declare a 
dividend on the Series I Preferred Stock, which shall be payable at the time 
and in the amount provided in Section 2(a).  If (i) any share or fraction of 
a share of Series I  Preferred stock is then outstanding, (ii) no dividend or 
other distribution (other than (x) a dividend on the Common Stock that is 
payable in shares of Common Stock or (y) a distribution solely on account of 
a reclassification of, or other split-up, division or combination of shares 
of, Common Stock) shall have been declared on the Common Stock during the 
period between the immediately preceding Quarterly Dividend Payment Date and 
the next succeeding Quarterly Dividend Payment Date or, with respect to the 
first Quarterly Dividend Payment Date, between the date of the first issuance 
of any share or fraction of a share of Series I  Preferred Stock and such 
first Quarterly Dividend Payment Date, and (iii) there are funds legally 
available for the payment of a dividend on the Series I  Preferred Stock, the 
Board shall, at any time prior to such next succeeding Quarterly Dividend 
Payment Date or such first Quarterly Dividend Payment Date, as the case may 
be, declare a dividend of $1.00 per share on the Series I  Preferred Stock, 
which shall be payable on such next succeeding Quarterly Dividend Payment 
Date or such first Quarterly Dividend Payment Date, as the case may be.

     (c)  Dividends on shares of Series I  Preferred Stock shall begin to 
accrue and be cumulative from the Quarterly Dividend Payment Date that 
immediately precedes the date of issuance of such shares unless (i) the date 
of issuance of such shares is prior to the record date for the determination 
of holders of shares of Series I  Preferred Stock entitled to receive a 
dividend on the first Quarterly Dividend Payment Date, in which event 
dividends on such shares shall begin to accrue and be cumulative from the 
date of issuance of such shares, (ii) the date of issuance of such shares is 
a Quarterly Dividend Payment Date, in which event dividends on such shares 
shall begin to accrue and be cumulative from such Quarterly Dividend Payment 
Date, or (iii) the date of issuance of such shares is a date after the record 
date for the determination of holders of shares of Series I  Preferred Stock 
entitled to receive a dividend on the Quarterly Dividend Payment Date that 
next succeeds the date of issuance of such shares, in which event dividends 
on such shares shall begin to accrue and be cumulative from such next 
succeeding Quarterly Dividend Payment Date.  Accrued but unpaid dividends on 
shares of Series I  Preferred Stock shall not bear interest.  If a dividend 
is declared on the Series I  Preferred Stock and the total amount of that 
dividend is less than the total amount of all dividends accrued and payable 
on all shares of Series I  Preferred Stock at the time of payment of that 
dividend, then the portion of the total amount of that dividend to be 
allocated to each of such shares shall be determined by

<PAGE>

multiplying the total amount of that dividend by a fraction, the numerator of 
which shall be the total amount of all dividends accrued and payable on that 
share at that time and the denominator of which shall be the total amount of 
all dividends accrued and payable on all such shares at that time.  The Board 
may fix a record date for the determination of holders of shares of Series I  
Preferred Stock entitled to receive a dividend r other distribution on the 
Series I  Preferred Stock, which record date shall be no more than 30 days 
prior to the date fixed for the payment of that dividend or other 
distribution.

     (d)  If at any time (i) any holder of shares of Series I  Preferred 
Stock would have been entitled under the foregoing provisions of this Section 
2 to have received by that time a dividend on such shares, assuming that such 
dividend had been declared, out of funds legally available for that purpose, 
at the time and in the amount provided in the foregoing provisions of this 
Section 2, and (ii) such dividend or any part thereof has not been paid to 
such holder, then such dividend or part thereof shall be considered accrued 
and payable at that time.

     Section 3.     VOTING.

     (a)  Subject to the provision for adjustment set forth in the next 
succeeding sentence, each share of Series I  Preferred Stock shall, except as 
otherwise provided by law, entitle the holder thereof to 1,000 votes on each 
matter that is submitted to a vote of stockholders of the Corporation.  In 
the event that the Corporation shall at any time after August 27, 1998, (i) 
declare a dividend on the Common Stock that is payable in shares of Common 
Stock, (ii) reclassify the Common Stock or (iii) otherwise effect a split-up, 
division or combination of shares of Common Stock, then in each such case the 
number of votes per share to which holders of shares of Series I  Preferred 
Stock were entitled immediately prior to such event shall be adjusted by 
multiplying such number by a fraction, the numerator of which shall be the 
number of shares of Common Stock that are outstanding immediately after such 
event and the denominator of which shall be the number of shares of Common 
Stock that were outstanding immediately prior to such event.

     (b)  Except as otherwise provided by law or in the Restated Certificate 
of Incorporation of the Corporation or the resolution or resolutions of the 
Board providing for the issuance of shares of Preferred Stock (including but 
not limited to these resolutions):

          (i)  the holders of shares of Series I  Preferred Stock, the holders
     of shares of Common Stock and the holders of shares of any other class or
     series of capital stock of the Corporation having general voting rights
     shall vote together as a single class on each matter that is submitted to 
     a vote of stockholders of the Corporation, and

          (ii) the holders of shares of Series I  Preferred Stock shall not 
     have any special voting rights.

<PAGE>

     Section 4.  CERTAIN RESTRICTIONS.  Unless and until all dividends at the 
time accrued and payable on all shares of Series I  Preferred Stock have been 
paid in full, the Corporation shall not:

          (a)  declare or pay any dividend, or make any other distribution, on
     any class or series of capital stock of the Corporation that ranks junior,
     either with respect to dividends or upon liquidation, dissolution or
     winding up, to the Series I Preferred Stock (any such class or series being
     referred to herein as "Junior Stock");

          (b)  declare or pay any dividend, or make any other distribution, on
     any class or series of capital stock of the Corporation that ranks in
     parity, either with respect to dividends or upon liquidation, dissolution
     or winding up, with the Series I  Preferred Stock (any such class or series
     being referred to herein as "Parity Stock"), except dividends that are paid
     ratably on all shares of Series I  Preferred Stock on which dividends are
     at the time accrued and payable and all shares of Parity Stock on which
     dividends are at the time accrued and payable in proportion to the total
     amounts of dividends at the time accrued and payable on all such shares;

          (c)  redeem, purchase or otherwise acquire for consideration any
     shares of Junior Stock, PROVIDED that the Corporation may at any time
     redeem, purchase or otherwise acquire shares of Junior Stock in exchange
     for shares of other Junior Stock; or

          (d)  redeem, purchase or otherwise acquire for consideration any
     shares of Series I  Preferred Stock or any shares of Parity Stock, except
     in accordance with an offer to purchase made in writing to all holders of
     such shares upon terms that the Board, after considering the relative
     rights and preferences of the respective series and classes of such shares,
     considers in good faith will result in fair and equitable treatment among
     the holders of such shares.

          Section 5.  REACQUIRED SHARES.  Any shares of Series I  Preferred 
Stock that are purchased or otherwise acquired by the Corporation in any 
manner whatsoever shall be retired and cancelled promptly after the 
acquisition thereof.  Upon their cancellation, all of such shares shall 
become authorized but unissued shares of Preferred Stock and thereafter may 
be issued as part of another series of Preferred Stock, subject to the rights 
of holders (if any) of shares of Series I  Preferred Stock set forth in these 
resolutions.

          Section 6.  LIQUIDATION, DISSOLUTION OR WINDING UP.  Upon any 
liquidation, dissolution or winding up of the Corporation:

          (a)  no distribution shall be made to the holders of shares of Junior
     Stock unless, prior to such distribution, the Corporation shall have paid
     to each holder of shares of Series I  Preferred Stock the sum of (i) $100
     per share of Series I  Preferred Stock held by such holder (such amount per
     share being referred to herein as the "Preference Amount") plus (ii) the
     total  amount of all dividends at the time accrued and payable on all
     shares of Series I  Preferred Stock held by such holder;

<PAGE>

          (b)  no distribution shall be made to the holders of shares of Parity
     Stock, except distributions that are made ratably on both all shares of
     Series I  Preferred Stock and all shares of Parity Stock in proportion to
     the total amounts to which the holders of all such shares are entitled upon
     such liquidation, dissolution or winding up; and

          (c)  each holder of shares of Series I  Preferred Stock shall be
     entitled to receive the sum of (i) the total amount of all dividends at the
     time accrued and payable on all shares of Series I Preferred Stock held by
     such holder plus (ii) an aggregate amount per share (such amount per share
     being referred to herein as the "Distributable Amount"), inclusive of the
     Preference Amount but subject to the provision for adjustment set forth in
     the next succeeding sentence, of Series I Preferred Stock held by such
     holder that is equal to 1,000 times the aggregate per share amount to be
     distributed to holders of shares of Common Stock upon such liquidation,
     dissolution or winding up.

In the event that the Corporation shall at any time after August 27, 1998, 
(1) declare a dividend on the Common Stock that is payable in shares of 
Common Stock, (2) reclassify the Common Stock or (3) otherwise effect a 
split-up, division or combination of shares of Common Stock, then in each 
such case the Distributable Amount to which a holder of shares of Series I  
Preferred Stock was entitled immediately prior to such event shall be 
adjusted by multiplying such Distributable Amount by a fraction, the 
numerator of which shall be the number of shares of Common Stock that are 
outstanding immediately after such event and the denominator of which shall 
be the number of shares of Common Stock that were outstanding immediately 
prior to such event.

     Section 7.  CONSOLIDATION, MERGER, ETC.  If the Corporation shall enter 
into any consolidation, merger, share exchange or other transaction in which 
all outstanding shares of Common Stock are exchanged for or changed into 
other securities, cash, other property or any combination thereof, then each 
outstanding share of Series I  Preferred Stock shall at the same time be 
similarly exchanged for or changed into an amount per share, subject to the 
provision for adjustment set forth in the next succeeding sentence, equal to 
1,000 times the aggregate amount of securities, cash and other property for 
which each outstanding share of Common Stock is exchanged or into which each 
outstanding share of Common Stock is changed.  In the event that the 
Corporation shall at any time after August 27, 1998, (1) declare a dividend 
on the Common Stock that is payable in shares of Common Stock, (2) reclassify 
the Common Stock or (3) otherwise effect a split-up, division or combination 
of shares of Common Stock, then in each such case the amount per share for 
which Series I Preferred Stock would be exchanged, or into the amount which 
Series I Preferred Stock would be changed, immediately prior to such event 
under the immediately preceding sentence of this Section 7, shall be adjusted 
by multiplying such amount by a fraction, the numerator of which shall be the 
number of shares of Common Stock that are outstanding immediately after such 
event and the denominator of which shall be the number of shares of Common 
Stock that were outstanding immediately prior to such event.

     Section 8.  REDEMPTION.  The shares of Series I  Preferred Stock shall not
be redeemable.

     Section 9.  RANKING.  The Series I  Preferred Stock shall rank junior to 
each other series of Preferred Stock, both with respect to dividends and upon 
liquidation, dissolution or winding up, unless the certificate of 
designation, powers, preferences and rights of such other series of Preferred 
Stock shall provide otherwise.

<PAGE>

     Section 10.  AMENDMENT.  If any share or fraction of a share of Series I 
Preferred Stock is outstanding, neither the Restated Certificate of 
Incorporation of the Corporation nor the resolution or resolutions of the 
Board providing for the issuance of shares of Preferred Stock (including but 
not limited to these resolutions) shall be amended in any manner that would 
materially alter or change the powers, preferences or rights of holders of 
shares of Series I  Preferred Stock so as to affect such holders adversely 
unless that amendment shall have received the affirmative vote of the holders 
of a majority of the outstanding shares of Series I Preferred Stock voting 
separately as a class.  Notwithstanding the foregoing provisions of this 
Section 10, whether or not a share or a fraction of a share of Series I 
Preferred Stock is outstanding, (a) the Board may from time to time provide 
by resolution or resolutions for the issuance of shares of Preferred Stock of 
one or more series that rank prior to the Series I  Preferred Stock, either 
with respect to dividends or upon liquidation, dissolution or winding up, or 
both with respect to dividends and upon liquidation, dissolution or winding 
up, and (b) no vote or consent of any holder of shares of Series I  Preferred 
Stock shall be required either as a condition to the adoption of such 
resolution or resolutions or as a condition to the issuance of such shares of 
Preferred Stock.

     Section 11.  FRACTIONAL SHARES.  Series I  Preferred Stock may be issued 
in fractions of a share.  Each holder of a fraction of a share of Series I 
Preferred Stock shall be entitled to exercise voting rights, to receive 
dividends and other distributions, and to have all other rights of the 
holders of whole shares of Series I  Preferred Stock in proportion to the 
fraction of a share of Series I  Preferred Stock held by that holder.

     RESOLVED FURTHER, that the proper officers of the Corporation be, and 
each of them hereby is, authorized to execute a Certificate of Designation, 
Powers, Preferences and Rights of Series I  Preferred Stock of the 
Corporation pursuant to Section 151 of the General Corporation Law of the 
State of Delaware and to take all appropriate action to cause that 
Certificate to be filed, recorded and become effective in accordance with 
Section 103 of the General Corporation Law of the State of Delaware."

     IN WITNESS WHEREOF, this Certificate has been executed this 17th day of 
August, 1998.

                               /s/ Socrates H. Choumbakos
                               ------------------------------------------------
                                        Socrates H. Choumbakos
                                        Senior Vice President,
                                          Corporate Planning and
                                          Development and Secretary

<PAGE>

                                          
                             CERTIFICATE OF RETIREMENT
                                         OF
                    CERTAIN CLASSES AND SERIES OF CAPITAL STOCK
                                         OF
                                    UROCOR, INC.
                                          
              (Pursuant to Section 243 of the General Corporation Law
                             of the State of Delaware)


     UroCor, Inc., a Delaware corporation (the "COMPANY"), hereby certifies as
follows:

     FIRST:    Article Fourth of the Company's Restated Certificate of
               Incorporation, as amended, authorizes the issuance of the
               following classes and series of shares of stock, each of which
               was originally created by amending and restating said Article
               Fourth:


<TABLE>
<CAPTION>
                                              Number of
Designation of Class or                  Authorized Shares of       Date of
Series of Shares of Stock                Each Class or Series       Creation
-------------------------                ---------------------      --------
<S>                                      <C>                        <C>
Class A Stock                                    513,093             5/9/91

Class B Stock                                     66,666             5/9/91

1991 Series A Preferred Stock, par value       1,199,999             5/9/91
$.01 per share

Series B Preferred Stock, par value $.01       1,467,608           11/26/91
per share

Series C Preferred Stock, par value $.01         981,071            9/30/92
per share

Series D Preferred Stock, par value $.01       1,154,397            3/29/94
per share

Series E Preferred Stock, par value $.01         763,320             6/2/95
per share

Series EG Preferred Stock, par value              60,000             6/2/95
$.01 per share

Series I Preferred Stock, par value $.01          80,000             5/9/91
per share

</TABLE>

<PAGE>

     SECOND:   On October 21, 1998, the Board of Directors of the Company, by 
               resolution, retired all of the shares of each class or series
               of stock listed above, which shares constituted all of the 
               authorized shares of each such class or series.

      THIRD:   Article Fourth of the Company's Restated Certificate of
               Incorporation, as amended, prohibits the reissuance of the shares
               of Class A Stock and Class B Stock and, accordingly, such shares
               are hereby eliminated from the authorized number of shares of
               capital stock of the Company.

     FOURTH:   Article Fourth of the Company's Restated Certificate of
               Incorporation, as amended, prohibits the reissuance of the shares
               of each series of preferred stock listed above as part of any
               such series and, accordingly, such shares are hereby restored to
               and shall assume the status of authorized but unissued and
               undesignated shares of the class of preferred stock of the
               Company.

      FIFTH:   Pursuant to the provisions of Section 243 of the General
               Corporation Law of the State of Delaware, all references in the
               Company's Restated Certificate of Incorporation, as amended, to
               the shares of each class and series of stock listed above are
               hereby eliminated.

     IN WITNESS WHEREOF, UroCor, Inc. has caused this certificate to be 
signed by Michael N. McDonald, its duly authorized officer, this 22nd day of 
October, 1998.

                                   UROCOR, INC.


                                 By /s/ Michael N. McDonald
                                    -------------------------------------------
                                        Michael N. McDonald, Vice President
                                        and Chief Financial Officer