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                                                                   Exhibit 10.35

     THIS NOTE HAS NOT BEEN REGISTERED UNDER THE SECURITIES ACT OF 1933, AS
AMENDED OR APPLICABLE STATE SECURITIES LAWS. THIS NOTE MAY NOT BE SOLD, OFFERED
FOR SALE, PLEDGED OR HYPOTHECATED IN THE ABSENCE OF AN EFFECTIVE REGISTRATION
STATEMENT AS TO THIS NOTE UNDER SAID ACT AND APPLICABLE STATE SECURITIES LAWS OR
AN OPINION OF COUNSEL THAT SUCH REGISTRATION IS NOT REQUIRED.

                           CONVERTIBLE PROMISSORY NOTE

$200,000                                                        October 19, 2001
                                                                Denver, Colorado

     FOR VALUE RECEIVED, Polar Molecular Corporation, a Delaware corporation
(the "Company") hereby promises to pay to the order of Lockhart Holdings, Inc.,
on or before the Maturity Date (as defined in Section 3(a) below), the principal
sum of Two Hundred Thousand Dollars ($200,000), together with interest thereon
as provided herein. The entire unpaid principal sum together with interest
thereon shall be due and payable on the Maturity Date.

     1. Conversion. The holder of this Note (the "Holder") is entitled, at its
option, on the Maturity Date to convert up to fifty percent (50%) of the
outstanding principal amount of this Note into options to purchase fully paid
and nonassessable shares of common stock, $0.0001 par value, of the Company
("Common Stock"), at the initial price (the "Conversion Price") per share of
Common Stock (the "Conversion Rate") equal to the higher of (a) $0.40 per share,
or (b) in the event the Company sells shares of Common Stock in a private
placement investment in excess of $250,000 prior to the date this Note is
converted, the average price per share of those shares sold in such private
placement (i.e., if the Note were converted on the Maturity Date for the maximum
amount allowed to be converted ($100,000), and no shares, or shares with a price
less than $0.40 per share, had been sold in a private placement, the Holder
would receive options to purchase 250,000 shares of Common Stock
($100,000/$0.40)). The Conversion Rate shall be subject to adjustment as
specified in Section 5 hereof. Conversion of this Note shall be effected by
surrender of this Note to the Company at its address specified below (or such
other address as the Company shall have given written notice to the Holder
hereof), together with a request that this Note be converted to options to
purchase Common Stock as specified herein.

     2. Interest. Interest shall be due upon the outstanding principal amount
hereof from the date of this Note through the date of repayment. No interest
shall be due and payable until the Maturity Date. The rate of interest shall be
12% per annum, compounded daily for the period. All interest hereunder, shall be
calculated on the basis of a 360 day year and actual days elapsed.

     3. Maturity Date; Payments.

          (a) The date for repayment of the principal amount and any interest
due hereunder shall be October 19, 2002 (the "Maturity Date"). At the sole
option of the Company, the date for such repayment may be extended until January
19, 2003 (in the event the date for

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repayment is extended, such extended date shall be the "Maturity Date"). The
Company shall give the Holder at least seven calendar days notice of its
election to extend the Maturity Date.

          (b) The Company shall make all payments due under the terms of this
Note to the Holder at 2873 West Hardies Road, Gibsonia, Pennsylvania 15044 or at
such other address as shall be designated to the Company in writing by the
Holder. The Company shall be entitled to prepay the Note in full, or in any
part, at any time. Any prepayment of principal shall be accompanied by the
payment of all interest accrued through the payment date. The Company shall give
at least fifteen calendar days notice of any prepayment hereunder, during which
time the Holder shall be entitled to convert this Note as specified in Section 1
hereof.

     4. Certain Expenses. Whenever the Holder shall sustain or incur any losses
or out-of-pocket expenses with respect to this Note in connection with (a)
repayment of overdue amounts under this Note, or (b) failure by the Company to
pay all principal and interest, if any, of this Note when due hereunder (whether
at maturity, by reason of acceleration, or otherwise), the Company shall pay, on
demand, to the Holder, in addition to any other penalties or premiums hereunder,
an amount sufficient to compensate the Holder for all such losses or
out-of-pocket expenses, including, without limitation, all costs and expenses of
a suit or proceeding (or any appeal thereof) brought for recovery of all or any
part of or for protection of the indebtedness evidenced by this Note or to
enforce the Holder's rights hereunder, including reasonable attorney's fees.

     5. Adjustment to Conversion Price.

          (a) If the Company at any time subdivides or combines its outstanding
shares of the Common Stock into a greater or lesser number of shares of the
Common Stock (including, without limitation, by stock dividend, stock split, or
recapitalization), then the Conversion Price shall be adjusted so that it shall
equal the price determined by multiplying the Conversion Price by a fraction,
the numerator of which shall be the number of shares of the Common Stock
outstanding immediately prior to such action and the denominator of which shall
be the number of shares outstanding immediately after giving effect to such
action.

          (b) In the event of any capital reorganization or reclassification of
the capital stock of the Company, any consolidation or merger of the Company
with or into another corporation, or any sale, lease or other disposition of all
or substantially all of the assets of the Company, that is effected in such a
manner that holders of shares of the Common Stock are entitled to receive
securities and/or property (including cash) with respect to or in exchange for
shares of the Common Stock, the Company shall, as a condition precedent to such
transaction, cause effective provision to be made so that the Holder shall have
the right thereafter to convert this Note for the kind and amount of securities
and/or other property receivable upon such event by a holder of the number of
shares of the Common Stock for which this Note could have been converted
immediately prior to such event, subject to the adjustments which shall be as
nearly equivalent as practicable to the adjustments provided for in this Note.

          (c) If the Company makes any distribution of its assets upon or with
respect to shares of the Common Stock as a liquidating or partial liquidating
dividend, or other than as a

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dividend payable out of legally available funds, the Holder shall upon
conversion of this Note thereafter, receive, in addition to the shares of the
Common Stock so purchased or paid, the amount of such assets (or, at the option
of the Company, a sum equal to the fair value thereof at the time of
distribution as determined by the Board of Directors of the Company in its
reasonable judgment) which would have been distributed to the Holder upon
conversion of this Note immediately prior to the record date for such
distribution.

          (d) Whenever the Conversion Price shall be adjusted as provided in
this Section 5, the Company shall forthwith deliver to Holder, a statement
showing in detail the facts requiring such adjustment and the Conversion Price
that shall be in effect after such adjustment. 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 5(e).

          (e) If the Company shall propose to take any action of the type
described in this Section 5, the Company shall give notice to the Holder, in the
manner set forth in Section 5(d), 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 the conversion of this Note. In the
case of any action which would require the fixing of a record date, such notice
shall be given at least 10 days prior to the date so fixed, and in case of all
other action, such notice shall be given at least 15 days prior to the taking of
such proposed action.

     6. Covenants as to Common Stock. The Company covenants and agrees that all
shares of Common Stock to be issued upon the exercise of options obtained upon
conversion of this Note, will, upon issuance, be validly issued, fully paid and
nonassessable and free from all taxes, liens and charges with respect to the
issuance thereof. Without limiting the generality of the foregoing, the Company
covenants that it will from time to time take all such actions as may be
requisite to assure that the stated or par value per share of Common Stock is at
all times equal to or less than the lowest Conversion Price per share of Common
Stock issuable upon exercise of options obtained upon conversion of this Note.
The Company further covenants and agrees that the Company will at all times have
authorized and reserved, a sufficient number of shares of its Common Stock to
provide for the exercise of options obtained upon conversion of this Note and
all other similar convertible notes issued by the Company. The Holder
acknowledges that neither this Note, the options to purchase shares of the
Common Stock issuable upon conversion of this Note (the "Conversion Options"),
or the shares of the Common Stock issuable upon exercise of the Conversion
Options (the "Conversion Shares") is registered under the Securities Act of 1933
(the "Securities Act") or any state securities laws. The Conversion Options or
Conversion Shares may be restricted securities, as that term is defined in the
Securities Act, and may be issued with a restrictive legend similar to the
legend on this Note.

     7. Security. This Note will be secured by a lien on and security interest
in certain property of the Company as provided in the Security Agreement dated
as of the date hereof (the "Note Security Agreement"). Such lien and security
interest will not become effective and attach until the lien and security
interest under that certain Security Agreement dated January 30, 2001

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is released. Reference is hereby made to the Note Security Agreement for a
description of the properties and assets in which the lien and security interest
will be granted, the nature and extent of the security, the terms and conditions
upon which the lien and security interest will be granted, and the rights of the
Holder with respect thereto.

     8. Time of Essence. Time is of the essence. At the option of the Holder,
payment of the principal sum and any and all accrued interest thereon may be
accelerated, and such amounts shall be immediately due and payable without
further notice or demand upon the occurrence (and continuance as hereinafter
specified) of any of the following:

          (a) Failure to make any payment of any and all amounts required to be
paid hereunder when due or declared due.

          (b) Default in the performance of any obligation or undertaking of the
Company under this Note.

          (c) Dissolution, termination of existence, insolvency, business
failure, appointment of a receiver of any part of the property of, assignment
for the benefit of creditors by, or commencement of any proceeding under any
bankruptcy or insolvency laws by, or against the Company which remains uncured
or undismissed for sixty (60) days after the occurrence of such event.

     9. Remedies Cumulative. The remedies provided in this Note shall be
cumulative, and shall be in addition to any other rights or remedies now or
hereafter provided by law or equity. No delay, failure or omission by the Holder
or any holder of this Note, in respect of any default by the Company, to
exercise any right of remedy shall constitute a waiver of the right to exercise
the right or remedy upon any such default or subsequent default.

     10. Waiver. The Company and any endorser hereof hereby waives presentment,
demand, notice of dishonor, notice of acceleration and protest and assents to
any extension of time with respect to any payment due under this Note, to any
substitution or release of collateral and to the addition or release of any
party. No waiver of any payment or other right under this Note shall operate as
a waiver of any other payment or right.

     11. Miscellaneous.

          (a) This Note or any provision hereof may be waived, changed,
modified, or discharged only by an agreement in writing, signed by the party
against whom enforcement of any waiver, change, modification or discharge is
sought.

          (b) If any of the provisions of this Note shall be held to be invalid
or unenforceable, the determination of invalidity or unenforceability of any
such provision shall not affect the validity or enforceability of any other
provision or provisions hereof.

          (c) This Note shall be binding upon the Company and its successors and
assigns and shall inure to the benefit of and be enforceable by the Holder and
its successors and assigns.

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          (d) All notices to the Company expressly required in this Note shall
be in writing and shall be delivered by hand delivery or mailed by certified
mail, return receipt requested, postage prepaid, addressed to the Company at its
address set forth below its signature hereto, or at such other address as the
Company shall notify the holder hereof. All such notices or other communications
shall be deemed properly given upon receipt of delivery by the Company.

          (e) At the option of the holder hereof, an action may be brought to
enforce this Note in a court of competent jurisdiction in the State of Colorado,
City and County of Denver. The Company and all signers or endorsers hereof
consent to such venue and jurisdiction.

          (f) This Note shall be construed and, enforced in accordance with the
laws of the State of Colorado.

                            [SIGNATURE PAGE FOLLOWS]

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     The Company has caused this Note to be executed as of the date set forth
above.

                                   POLAR MOLECULAR CORPORATION,
                                     a Delaware corporation


                                   By: /s/ Mark L. Nelson
                                       -----------------------------------------
                                           Mark L. Nelson
                                           President and Chief Executive Officer

                                       Address: 4600 S. Ulster Street
                                                Suite 700
                                                Denver, Colorado 80237

<PAGE>

                            LOAN EXTENSION AGREEMENT

     This Loan Extension Agreement (this "Agreement") is entered into by and
between Polar Molecular Corporation, a Delaware corporation (the "Company"), and
Lockhart Holdings, Inc. (the "Holder") as of January 17, 2003.

                                    RECITALS

A.   The Company issued to the Holder a Promissory Note (the "Note") in the
     principal amount of $200,000 dated as of October 19, 2001;

B.   The Holder and the Company desire to extend the due date of the Note and
     amend the terms for repayment of the Note.

                                    AGREEMENT

     In consideration of the foregoing and the mutual promises contained herein,
the Holder and the Company hereby agree as follows:

1. Section 1 of the Note is hereby amended by inserting in the second line
thereof, after the words "Maturity Date," the following:

          "to notify the Company"

2. Section 2 of the Note is hereby amended to read in its entirety as follows:

          "2. Interest. Interest shall be due upon the outstanding principal
          amount hereof from the date of this Note through the Maturity Date. In
          the event that the Holder exercises its conversion right on the
          Maturity Date, interest shall continue to accrue against only the
          outstanding principal amount hereunder, as adjusted downward for (i)
          amounts converted pursuant to Section 1 hereof, and (ii) principal
          payments made pursuant to Section 3 hereof. No interest shall be due
          and payable until the date of final repayment pursuant to the terms of
          Section 3 hereof. The rate of interest shall be 12% per annum,
          compounding daily for the period. All interest hereunder shall be
          calculated on the basis of a 360 day year and actual days elapsed."

3.   Subsection (a) of Section 3 of the Note is hereby amended to read in its
     entirety as follows:

          "(a) The date for repayment of the principal amount and any interest
          due hereunder shall be July 19, 2003 (the "Maturity Date"). Following
          the Maturity Date, the Company shall be obligated to repay all
          outstanding principal and interest accrued under the Note in quarterly
          installments of at least $25,000, until such time as all outstanding
          amounts of principal and interest are paid in full."

<PAGE>

4.   Consideration. As consideration for entering into this Agreement, the
     Company shall issue the Holder 50,000 shares of the Company's common stock
     to be delivered promptly within 10 business days of final execution of this
     Agreement.

5.   Effect of this Agreement.

     (a)  The Holder hereby agrees that as of the date of this Agreement the
          Company shall not be in default under the Note or under any other
          related agreement including, without limitation, the Security
          Agreement (the "Security Agreement") between the Company and the
          Holder dated as of October 24, 2001. The Holder hereby waives any
          remedies it may have had under the Note or the Security Agreement
          prior to the date of this Agreement as a result of the Company's
          failure to pay the Note in full on or before the original due date of
          January 19, 2003 (although the Holder retains any remedies relating to
          any future defaults).

     (b)  The Company hereby agrees that failure to repay the Note in accordance
          with this Agreement and the repayment terms set forth herein or
          failure to perform or comply in any material respect with any of the
          obligations set forth in this Agreement shall constitute an Event of
          Default (as that term is defined in the Note) under the Note and the
          Security Agreement. Notwithstanding anything herein, upon the
          occurrence of such an Event of Default hereunder, the Holder shall be
          entitled to all rights and remedies provided for by the terms of the
          Note and the Security Agreement.

     (c)  Other than those terms specifically addressed by this Agreement, the
          terms of the Note shall not be altered or amended by this Agreement.
          In the event of a conflict between the terms of the Note and this
          Agreement, the terms of this Agreement shall control and be binding on
          the Holder and the Company.

6.   Miscellaneous

     (a)  This Agreement shall be binding on the Company and its successors, and
          shall inure to the benefit of the Holder, its successors and assigns.
          Any reference to the Holder shall include any holder in due course of
          the Note.

     (b)  This Agreement, the Note and the Security Agreement together
          constitute the entire agreement between the Holder and the Company
          with respect to the subject matter hereof and supersedes all prior
          oral or written agreements and understandings, if any, relating to the
          subject matter hereof.

     (c)  Each provision of this Agreement shall be considered separate. If for
          any reason any provision or provisions hereof are determined to be
          invalid or contrary to applicable law, such invalidity shall not
          impair the operation of or affect the remaining portions of this
          Agreement.

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     (d)  This Agreement may be executed in one or more counterparts, each of
          which shall be deemed an original, but all of which shall together
          constitute one and the same instrument.

     The undersigned have executed this Agreement to be effective as of the date
first set forth herein.


COMPANY:

POLAR MOLECULAR CORPORATION


By: /s/ Mark L. Nelson
    -----------------------------------
        Mark L. Nelson, President and
        Chief Executive Officer


HOLDER:

LOCKHART HOLDINGS, INC.


By: /s/ Thomas J. Gillespie
    -----------------------------------
        Thomas J. Gillespie, Jr., President

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