EXHIBIT 10.20



[METRA
 BIOSYSTEMS LOGO]

                      INTERNATIONAL DISTRIBUTOR AGREEMENT

     This International Distributor Agreement (the "Agreement") is entered 
into in Palo Alto, California, as of April 8, 1993, between METRA BIOSYSTEMS, 
INC., a corporation organized under the laws of California, United States of 
America, with principal offices at 3181 Porter Drive, Palo Alto, California 
94304, United States of America, ("Manufacturer") and Amersham K.K., an 
organization organized under the laws of Japan with offices at Tokyo Toyama 
Kaikan, 1-3, Kakusan 5-Chome, Bunkyo-ku, Tokyo 112, Japan ("Distributor").

     In consideration of the mutual promises contained herein, the parties 
agree as follows:

     1.   DEFINITIONS

         (a)  "Products" shall mean those products listed in EXHIBIT A 
attached hereto to be distributed solely for research purposes. Metra 
Biosystems may appoint other parties to develop and commercialize products 
for clinical use. Products may be changed, abandoned or added by 
Manufacturer, at Manufacturer's sole discretion, provided that Manufacturer 
gives ninety (90) days' prior written notice to Distributor. Manufacturer 
shall be under no obligation to continue the production of any Product, 
except as provided herein.

         (b)  "Territory" shall mean that geographic area identified in 
EXHIBIT B attached hereto.

     2.   APPOINTMENT AND AUTHORITY OF DISTRIBUTOR

         (a)  APPOINTMENT.  Subject to the terms and conditions set forth 
herein, Manufacturer hereby appoints Distributor as Manufacturer's 
distributor for the Products in the Territory, and Distributor hereby accepts 
such appointment. For so long as Distributor is performing in compliance with 
this Agreement, Manufacturer shall not appoint any other distributor with 
responsibility for sale of the Products in the Territory.

         (b)  TERRITORIAL RESPONSIBILITY.  Distributor shall not promote the 
Products outside the Territory or establish a facility for purposes relating 
to the Products outside the Territory. Distributor shall forward to 
Manufacturer all unsolicited inquiries relating to the Products from 
customers or potential customers outside the Territory.

         (c)  OTHER DISTRIBUTORS.  In the event that Manufacturer receives 
requests for information relating to, or purchase orders for, the Products 
from customers or potential customers within the Territory, Manufacturer 
shall forward such requests or orders to Distributor. Notwithstanding the 
above, nothing in this




Agreement shall prevent Manufacturer's other distributors from selling 
Products in the Territory, so long as such sales are not solicited in the 
Territory. In the event that Distributor becomes aware that other 
distributors of Manufacturer are selling Products in the Territory, and 
provides Manufacturer written notice thereof, Manufacturer will use 
Manufacturer's commercially reasonable efforts to limit such sales of Products.

         (d)  CONFLICT OF INTEREST.  Distributor warrants to Manufacturer that 
Distributor does not currently represent or promote any lines or products 
that compete with the Products. During the term of this Agreement, 
Distributor shall not, without Manufacturer's prior written consent, 
represent, promote or otherwise try to sell within the Territory any lines or 
products that, in Manufacturer's judgment, compete with the Products covered 
by this Agreement.

         (e)  INDEPENDENT CONTRACTORS.  The relationship of Manufacturer and 
Distributor established by this Agreement is that of independent  
contractors, and nothing contained in this Agreement shall be construed to 
give either party the power to direct and control the day-to-day activities 
of the other or allow one party to create or assume any obligation on behalf 
of the other for any purpose whatsoever. All financial obligations associated 
with Distributor's business are the sole responsibility of Distributor. All 
sales and other agreements between Distributor and Distributor's 
customers are Distributor's exclusive responsibility and shall have no effect 
on Distributor's obligations under this Agreement.

     3.   TERMS OF PURCHASE OF PRODUCTS BY DISTRIBUTOR

         (a)  TERMS AND CONDITIONS.  All purchases of Products by Distributor 
from Manufacturer during the term of this Agreement shall be subject to the 
terms and conditions of this agreement.

         (b)  PRICES.  All prices of Products are F.O.B. Manufacturer's 
Distribution Site at the address listed for Manufacturer at the beginning of 
this Agreement or as provided by written notice to Distributor. The purchase 
price to Distributor for each of the Products ("Purchase Price") shall be as 
set forth in EXHIBIT A attached hereto. The difference between Distributor's 
Purchase Price and Distributor's selling price to Distributor's customers 
shall be Distributor's sole remuneration for sale of the Products. 
Manufacturer has the right at any time to revise the prices in EXHIBIT A with 
sixty (60) days' advance written notice to Distributor; PROVIDED, that 
Manufacturer shall not revise such prices more than once each calendar year. 
Such revisions shall apply to all orders received after the effective date of 
revision. Price changes shall not affect unfulfilled purchase orders accepted 
by Manufacturer prior to the effective date of the price change.

         (c)  TAXES.  Distributor's Purchase Price does not include any 
federal, state or local taxes that may be applicable to the Products. In the 
event that such taxes are applicable and Manufacturer has the legal 
obligation to collect such taxes, Manufacturer shall be entitled to add to 
Distributor's invoice the amount of such taxes and Distributor shall pay such 
amount unless Distributor provides

                                        -2-



Manufacturer with a valid tax exemption certificate authorized by the 
appropriate taxing authority.

         (d)  ORDER AND ACCEPTANCE.  All orders for Products submitted by 
Distributor shall be initiated by written purchase orders sent to 
Manufacturer and requesting a delivery date during the term of this 
Agreement; PROVIDED, HOWEVER, that an order may initially be placed orally or 
by telecopy if a confirmational written purchase order is received by 
Manufacturer within five (5) days after said oral or telecopy order. To 
facilitate Manufacturer's production scheduling, Distributor shall submit 
purchase orders to Manufacturer at least sixty (60) days prior to the first 
day of the requested month of delivery. No order shall be binding upon 
Manufacturer until accepted by Manufacturer in writing, and Manufacturer 
shall have no liability to Distributor with respect to purchase orders that 
are not accepted. No partial shipment of an order shall constitute the 
acceptance of the entire order, absent the written acceptance of such entire 
order. Manufacturer shall use Manufacturer's reasonable best efforts to 
deliver Products at the times specified either in Manufacturer's quotation or 
in Manufacturer's written acceptance of Distributor's purchase orders. 
Notwithstanding the foregoing, Manufacturer shall have no obligation to 
supply Products to Distributor during any period for which Distributor's 
payments to Manufacturer hereunder are thirty (30) days or more past due.

         (e)  TERMS OF PURCHASE ORDERS.  Distributor's purchase orders 
submitted to Manufacturer from time to time with respect to Products to be 
purchased hereunder shall be governed by the terms of this Agreement and 
Manufacturer's published Standard Terms and Conditions of Sale as in effect 
at the time of such purchase, PROVIDED that, in the event of any conflict 
between the terms of this Agreement and the Standard Terms and Conditions of 
Sale of Manufacturer then in effect, this Agreement shall be controlling. 
Nothing contained in any purchase order of Distributor shall in any way 
modify such terms of purchase of Manufacturer or add any additional terms or 
conditions.

         (f)  PAYMENT.  Full payment of Distributor's Purchase Price for the 
Products (including any freight, taxes or other applicable costs initially 
paid by Manufacturer but to be borne by Distributor) shall be in United States 
of America dollars. All exchange, interest, banking, collection, and other 
charges shall be at Distributor's expense. Payment terms shall be 
[net forty-five] ([45]) days, and payment shall be made by wire transfer, 
check or other instrument approved by Manufacturer. Any invoiced amount not 
paid when due shall be subject to a service charge at the lower of the rate 
of [one and one-half] percent ([1.5]%) per month or the maximum rate 
permitted by law. If Distributor fails to make any payment to Manufacturer 
when due, Manufacturer may, without affecting its rights under this 
Agreement, cancel or delay any future shipments of the Products to 
Distributor.

         (g)  SHIPPING.  All Products delivered pursuant to the terms of this 
Agreement shall be suitably packed for air freight shipment in Manufacturer's 
standard shipping cartons, marked for shipment at Manufacturer's manufacturing
plant to Distributor's address set forth above, and delivered to Distributor 
or Distributor's carrier agent F.O.B. Manufacturer's Distribution Site, at 
which time title to such Products and risk of loss shall pass to Distributor. 
All shipments of 

                                        -3-



Products shall include a Certificate of Analysis for each lot. Manufacturer 
shall deliver Products to the carrier selected by Distributor. In the event 
that Distributor does not provide written notice of such carrier, 
Manufacturer shall select the carrier. All freight, insurance, and other 
shipping expenses, as well as any special packing expense, shall be paid by 
Distributor. Distributor shall also bear all applicable taxes, duties, 
and similar charges that may be assessed against the Products after delivery 
to the carrier at Manufacturer's Distribution Site.

         (h)  REJECTION OF PRODUCTS.  Distributor shall inspect all Products 
promptly upon receipt thereof, such inspection to include, without 
limitation, a quality control analysis to determine whether Products and, 
where applicable, components thereof meet the specifications set forth in 
then-current package inserts for such Products and components and the 
Certificate of Analysis accompanying each shipment of Products. Distributor 
may reject any Product or component thereof that fails in any material way to 
meet such specifications. In the event that Distributor is not able to 
conduct a quality control analysis, Distributor, at Distributor's expense, 
may utilize contract facilities to conduct such analysis. Manufacturer will 
maintain samples of each production lot of Product, and Distributor will 
maintain samples of each shipment lot of Product, for archival purposes. Any 
Product or component thereof not properly rejected within four (4) weeks 
after receipt of that Product by Distributor ("Rejection Period") shall be 
deemed accepted. If any Product is shipped by Distributor to Distributor's 
customer prior to expiration of the Rejection Period, such unit shall be 
deemed accepted upon shipment by Distributor. To reject a Product or a 
component thereof, Distributor shall, within the Rejection Period, notify 
Manufacturer in writing or by telecopy of Distributor's rejection of such 
Product or component, stating the reason for such rejection. In the event 
that Manufacturer, in Manufacturer's sole discretion, desires that 
Distributor return a rejected Product or component thereof to Manufacturer, 
Distributor shall return to Manufacturer the rejected Product or component 
thereof, freight prepaid. Manufacturer will provide Distributor a credit to 
be applied against Distributor's future Product orders equal to the freight 
charges prepaid by Distributor for properly rejected Products or components 
thereof. As promptly as possible but no later than thirty (30) working days 
after receipt by Manufacturer of properly rejected Products or components 
thereof, Manufacturer shall replace such Products or components. Manufacturer 
shall pay shipping charges in connection with shipment of replaced Products 
or components thereof to Distributor for properly rejected Products; 
otherwise, Distributor shall be responsible for shipping charges. In the 
event that such replaced Products or components are shipped to Distributor 
together with Products corresponding to a purchase order pursuant to this 
Agreement, shipping charges in connection with such shipment shall be 
pro-rated between Manufacturer and Distributor. After the Rejection Period, 
Distributor may not return any Products or, if applicable, components thereof 
to Manufacturer for any reason without Manufacturer's prior written consent.

     4.  TRAINING AND SERVICE

        (a)  SERVICES BY DISTRIBUTOR.  Distributor shall have the 
responsibility to deliver the Products and train the customers with respect 
to the Products sold.

                                        -4-




The services shall (i) be performed only by specially and properly trained 
personnel of Distributor, (ii) be of the highest quality, and (iii) be 
performed promptly.

       (b)  TRAINING BY MANUFACTURER.  Manufacturer shall provide sales and 
technical training, and technical support, to Distributor's personnel at 
periodic intervals, with the frequency and content of the training to be 
determined by agreement between Distributor and Manufacturer. Manufacturer 
and Distributor shall each pay their own costs for travel, food, and lodging 
during the training period. In addition to sales and technical training, 
Manufacturer shall cooperate with Distributor in establishing efficient 
promotional procedures and policies. Manufacturer shall promptly respond to 
Distributor's reasonable technical questions relating to Product.

     5.  WARRANTY TO DISTRIBUTOR'S CUSTOMERS

        (a)  STANDARD LIMITED WARRANTY.  Manufacturer warrants that the 
Products sold to Distributor will comply at the time of shipment to 
Distributor with the requirements of the U.S. Federal Food, Drug and Cosmetic 
Act, if applicable. This warranty is contingent upon proper use of a Product 
in the application for which such Product was intended and does not cover 
Products that were modified without Manufacturer's approval, that have 
expired or that were subjected by the customer to unusual physical, chemical 
or electrical stress.

        (b)  NO OTHER WARRANTY.  EXCEPT FOR THE EXPRESS LIMITED WARRANTY SET 
FORTH IN SUBSECTION 5(a) ABOVE, MANUFACTURER GRANTS NO WARRANTIES FOR THE 
PRODUCTS, (EXCEPT FOR THE IMPLIED WARRANTY OF TITLE) EXPRESS OR IMPLIED, 
EITHER IN FACT OR BY OPERATION OF LAW, BY STATUTE OR OTHERWISE, AND 
MANUFACTURER SPECIFICALLY DISCLAIMS ANY IMPLIED WARRANTY OF QUALITY, WARRANTY 
OF MERCHANTABILITY, WARRANTY OF FITNESS FOR A PARTICULAR PURPOSE OR WARRANTY 
OF NONINFRINGEMENT.

        (c)  LIMITATION OF LIABILITY.  MANUFACTURER'S LIABILITY UNDER THE 
WARRANTY SHALL BE LIMITED TO A REFUND OF THE CUSTOMER'S PURCHASE PRICE. IN NO 
EVENT SHALL MANUFACTURER BE LIABLE FOR THE COST OF PROCUREMENT OF SUBSTITUTE 
GOODS BY THE CUSTOMER OR FOR ANY DIRECT, INDIRECT, SPECIAL, CONSEQUENTIAL OR 
INCIDENTAL DAMAGES FOR BREACH OF WARRANTY, EXCEPT INSOFAR AS SUCH DAMAGES 
RELATE TO DEATH OR PERSONAL INJURY RESULTING FROM MANUFACTURER'S GROSS 
NEGLIGENCE.

       (d)  NO VERBAL REPRESENTATIONS OR WARRANTIES.  Manufacturer shall not 
be bound by any representations or statements on the part of its employees or 
agents whether oral or in writing and including those made in catalogues and 
other promotional material (excluding technical details and specifications) 
except where such representations or statements are expressly made part of 
this Agreement.

                                        -5-




     6.  ADDITIONAL OBLIGATIONS OF DISTRIBUTOR

         (a)  HEALTH AND SAFETY LAWS AND REGULATIONS.  Distributor shall 
comply fully, at its expense, with any and all applicable health and 
safety laws and regulations of the Territory.

         (b)  REGISTRATIONS, LICENSES AND PERMITS.  Distributor agrees to use 
its best efforts to investigate, obtain government approval for, promote and 
distribute the Products, (solely for research purposes) at its own expense, 
in the Territory as soon as feasible after the date of this Agreement, using 
generally the same channels and methods, exercising the same diligence and 
adhering to the same standards which it employs with respect to other 
research products sold by Distributor, as well as Distributor's own products, 
if any. Unless prohibited by local law, all such registrations and approvals 
obtained by Distributor shall be in the name of Manufacturer. In particular, 
Distributor shall, at its own expense:

              (i)  Exercise due diligence to promptly obtain and maintain 
     government approvals to import, register and market the Products in each 
     jurisdiction in the Territory and to diligently proceed to secure and 
     maintain, as may be required from time to time, government importing, 
     registration and marketing approvals, customs clearances and currency 
     authorizations and any permits necessary in each jurisdiction in the 
     Territory. Distributor shall keep Manufacturer generally informed of the 
     regulatory requirements in each jurisdiction in the Territory and shall 
     submit to the government health authorities in each jurisdiction in the 
     Territory where sale of the Products is planned a complete application 
     for registration and marketing approval of the Products by the date set 
     forth in any marketing plan required by Manufacturer below. Distributor 
     shall file for regulatory approval for the sale of Products in the 
     Territory by Amersham K.K. If Manufacturer so requests, Distributor 
     shall notify Manufacturer each time it submits an application for 
     government registration and marketing approval for the Products and 
     shall, at Manufacturer's request, supply Manufacturer with copies of or 
     access to Distributor's filings and clinical data and shall keep 
     Manufacturer fully informed of the progress of each such application. 
     Manufacturer and Distributor agree to disclose promptly to the other all 
     reports and any information which they have available or which become 
     available to them relating to performance of, or any deleterious 
     physiological effects caused by or related to, the Products.


                                     -6-




              (ii)  Within thirty (30) days after the date of this Agreement, 
     submit to Manufacturer a complete marketing plan, prepared by 
     Distributor in good faith, which shall be subject to approval by 
     Manufacturer, for the Products in each jurisdiction in the Territory. 
     Such plan shall be updated and delivered to Manufacturer annually and 
     shall include, at a minimum, information on competitive products; 
     proposed labeling (including label, package insert, introductory folder 
     and advertising); estimated sales volume; anticipated quantities of the 
     Products to be purchased from Manufacturer; distribution and promotional 
     plans; schedule for submission of applications for government 
     registration and marketing approval; and marketing program. All Product 
     labels, package inserts and claims, which are prepared for or by 
     Distributor, shall meet all legal requirements of the jurisdiction in 
     which the Products are marketed and shall be subject to Manufacturer's 
     prior review and approval.

              (iii)  Commence marketing of the Products throughout the 
     Territory immediately after receipt of government health registration 
     approvals, if applicable. Distributor shall be deemed to have commenced 
     the marketing of the Products only when it shall have offered the 
     Products regularly for sale.

              (iv)  Use its best efforts to distribute and sell the Products 
     for research purposes only and for use only by qualified individuals, as 
     appropriate in the Territory, in compliance with local laws and 
     regulations and good commercial practice and for uses and applications 
     reasonably approved by Manufacturer for the Products.

In the event that all necessary registrations, licenses and permits required 
to sell and distribute the Products in the Territory for clinical use (if 
applicable) are not obtained within nine (9) months after the effective date 
of this Agreement, Manufacturer may, in its sole discretion, terminate this 
Agreement upon written notice to Distributor.

         (c)  QUARTERLY PURCHASE COMMITMENT.  Distributor hereby agrees to 
purchase from Manufacturer during the first eight (8) calendar quarter 
periods commencing June 1, 1993 ("Quarterly Purchase Commitment") the number 
of Products set forth on EXHIBIT C. Annually thereafter, Distributor and 
Manufacturer shall mutually agree in writing on the Quarterly Purchase 
Commitment for the next four calendar quarter periods. Throughout the term of 
this Agreement, if (i) the parties cannot agree on Quarterly Purchase 
Commitments, or (ii) Distributor fails to purchase Distributor's Quarterly 
Purchase Commitment in any given calendar quarter and Distributor's Quarterly 
Purchase Commitment in the next calendar quarter plus the deficit in 
Distributor's Quarterly Purchase Commitment from the preceding calendar 
quarter, then, without prejudice to Manufacturer's other rights under this 
Agreement (including the right to terminate this Agreement upon written 
notice to Distributor), Manufacturer may appoint one or more additional 
distributors for sale of the Products in the Territory. Products returned to 
Manufacturer under the provisions of Subsection 3(h) above shall not count 
towards the fulfillment of Distributor's relevant Quarterly Purchase 
Commitment.


                                    -7-



         (d)  FORECASTS.  Within the first five (5) days of every month, 
Distributor shall provide Manufacturer with a ninety (90) day rolling 
forecast showing prospective orders by Product and Distributor's anticipated 
Products purchase order submission date. Such rolling forecasts shall be 
non-binding and shall be used by Manufacturer for information purposes only.

         (e)  PROMOTION OF THE PRODUCTS.  Distributor shall, solely at 
Distributor's own expense, vigorously promote the sale of the Products within 
the Territory. Such promotion shall include, but not be limited to, preparing 
all promotional materials intended specifically for use in the Territory in 
appropriate languages for the Territory, advertising the Products in trade 
publications within the Territory, participating in appropriate trade shows, 
and directly soliciting orders from customers within the Territory for the 
Products. Distributor and its employees and agents shall not promote the 
Products for any indications not approved for such Products by applicable 
regulatory authorities. All promotional materials prepared by Distributor 
relating to the Products must be consistent with applicable law and 
promotional materials used by Manufacturer or other distributors of 
Manufacturer in connection with the Products. Distributor shall provide to 
Manufacturer for purposes of review and comment by Manufacturer any and all 
promotional, advertising, and educational materials and programs (in the 
English language and the actual language of labeling) relating to the 
Products at least thirty (30) days prior to the release of such materials or 
commencement of such programs. Manufacturer shall make its best efforts to 
provide to Distributor, within ten (10) business days after receipt of such 
materials and/or programs, any and all comments and suggestions relating to 
such materials and/or programs. In addition, Manufacturer shall be entitled, 
on Manufacturer's written request, to receive copies of any promotional 
materials used by Distributor and inspect such materials for purposes of 
determining that such materials are consistent with promotional materials 
used by Manufacturer or other distributors of Manufacturer. Distributor shall 
provide Manufacturer, within ten (10) days after the end of each calendar 
quarter, a description of Distributor's activities in promoting the Products 
within the Territory. Distributor agrees to not promote, or solicit orders 
for, the Products outside the Territory. Distributor shall use its best 
efforts to locate and introduce to Manufacturer appropriate pharmaceutical 
and bone densitometry companies in the Territory with which Manufacturer may 
want to establish education programs with respect to Products.

         (f)  REPRESENTATIONS.  Distributor shall make any false or 
misleading representations to customers or others regarding Manufacturer or 
the Products. Distributor and its employees and agents shall not make any 
representations, warranties or guarantees with respect to the specifications, 
features or capabilities of the Products that are not consistent with 
Manufacturer's documentation accompanying the Products or Manufacturer's 
literature describing the Products, including Manufacturer's standard 
limited warranty and disclaimers.

         (g)  INVENTORY.  Distributor shall, at Distributor's own expense, 
maintain a sufficient inventory of the Products at all times during the term 
of this Agreement as necessary in order to meet the requirements of any 
customer or potential customer within the Territory.


                                   -8-



         (h)  FINANCES AND PERSONNEL.  Distributor shall maintain a net worth 
and working capital sufficient, in Manufacturer's reasonable judgment, to 
allow Distributor to perform fully and faithfully Distributor's obligations 
under this Agreement. Distributor shall devote sufficient financial resources 
and technically qualified sales and training personnel to the Products to 
fulfill Distributor's responsibilities under this Agreement.

         (i)  CUSTOMER AND SALES REPORTING.  Distributor shall, at 
Distributor's own expense and consistent with the sale policies of 
Manufacturer: (i) place the Products in Distributor's literature as soon as 
possible; (ii) provide adequate contact with existing and potential customers 
within the Territory on a regular basis, consistent with good business 
practice; (iii) assist Manufacturer in assessing customer requirements for 
the Products, including modifications and improvements thereto, in terms of 
quality, design, functional capability, and other features; and (iv) provide 
Manufacturer on a quarterly basis: (1) a summary of all purchase orders 
received by Distributor for Products, (2) market research information, as 
reasonably requested by Manufacturer for purposes of Manufacturer's market 
research, regarding competition and changes in the market within the 
Territory and (3) a summary of the number of Products held by Distributor at 
the end of such quarter.

         (j)  AUDITS.  Manufacturer reserves the right to authorize a 
representative of Manufacturer, at Manufacturer's expense, to audit 
Distributor's records relating to the Products, including, without 
limitation, records relating to preclinical and clinical trials, interactions 
between Distributor and principal investigators in such preclinical and 
clinical trials, inventories and sales. Upon prior written notice, 
Distributor shall provide reasonable access to such records during normal 
business hours at Distributor's business locations. Distributor shall maintain 
all records at Distributor's location for a minimum of two (2) years after 
termination of this Agreement.

         (k)  IMPORT AND EXPORT REQUIREMENTS.  Distributor shall, at 
Distributor's own expense, obtain and pay for import and export licenses and 
permits, pay customs charges and duty fees, and take all other actions 
required to accomplish the export and import of the Products purchased by 
Distributor. Distributor understands that Manufacturer is subject to 
regulation by agencies of the United States of America government, including 
the United States of America Department of Commerce, which prohibit export or 
diversion of certain technical products to certain countries. Distributor 
warrants that Distributor will comply in all respects with the export and 
re-export restrictions set forth in the export license for every Product 
shipped to Distributor.

         (l)  LIMITATION ON DISTRIBUTOR'S RIGHTS TO THE PRODUCTS. Distributor 
shall have no right to copy, modify or remanufacture any Product or part 
thereof. Distributor shall not make any changes, alterations, modifications 
or additions to the Products without prior written approval of Manufacturer.

         (m)  PRODUCT SPECIFICATIONS.  Distributor shall ensure that the 
specification of the Products ordered is suitable and safe for the intended 
use or


                                  -9-



environment of use, except where it makes known details of such use to 
Manufacturer in writing prior to conclusion of the Agreement in such a way as 
clearly to place reliance on Manufacturer's special skills.

         (n)  PRODUCT HANDLING.  Distributor shall handle the Products in a 
suitable and safe manner and shall comply with any instructions supplied to 
it by Manufacturer. Distributor shall also pass on to users (including 
purchasers and users of other goods and equipment into which the Products are 
incorporated) all relevant safety information.

         (o)  INTELLECTUAL PROPERTY.  Where Distributor supplies designs, 
drawings and specifications to Manufacturer to enable Manufacturer to 
manufacture non-standard or custom made Products, Distributor warrants that 
such manufacture will not infringe the intellectual property rights of any 
third party.

     7.  ADDITIONAL OBLIGATIONS OF MANUFACTURER.  Manufacturer shall 
promptly provide Distributor with Manufacturer's core materials relating to 
promotion of the Products. Such core materials shall be provided primarily in 
the English language. Manufacturer shall promptly respond to all reasonable 
inquiries from Distributor concerning matters pertaining to this Agreement. 
Manufacturer shall refrain from giving quotations to exporters for Products 
to be shipped to the Territory. Manufacturer shall inform Distributor of new 
product developments relating to the Products. Manufacturer shall forward to 
Distributor copies of all approval letters received from the U.S. Food and 
Drug Administration with respect to Products.

     8.  TERM AND TERMINATION

         (a)  TERM.  This Agreement shall commence on the date hereof and 
continue in full force and effect for a fixed term of two (2) years from such 
date, unless terminated earlier under the provisions of this Section 8. At 
the end of such fixed term, this Agreement may be renewed for a fixed term of 
two (2) years; PROVIDED, that Manufacturer and Distributor agree in writing 
prior to the end of such fixed term upon the terms and conditions of such 
renewal, including, without limitation, minimum quantities of Products to be 
purchased by Distributor during such two (2) year fixed term. Manufacturer 
shall also have the right to terminate this Agreement upon written notice to 
Distributor as provided in Section 6 hereof.

         (b)  TERMINATION FOR CAUSE.  If either party defaults in the 
performance of any provision of this Agreement, then the non-defaulting party 
may given written notice to the defaulting party that if the default is not 
cured within thirty (30) days the Agreement will be terminated. If the 
non-defaulting party gives such notice and the default is not cured during 
such thirty (30) day period, then the Agreement shall automatically terminate 
at the end of that period.

         (c)  TERMINATION FOR INSOLVENCY.  This Agreement shall terminate, 
without notice, (i) upon the institution by or against Distributor of 
insolvency, receivership or bankruptcy proceedings or any other proceedings 
for the settlement



                                   -10-




of Distributor's debts, (ii) upon Distributor's making an assignment for the 
benefit of creditors, or (iii) upon Distributor's dissolution or ceasing to 
do business.

         (d)  CLINICAL USE REGULATORY APPROVAL; TECHNICAL DIFFICULTIES. The 
rights of Distributor hereunder with respect any one Product may be 
terminated by Manufacturer, upon thirty (30) days' prior written notice, at 
any time following approval from appropriate Japanese governmental 
authorities to distribute such Product for clinical use. Where Manufacturer 
experiences technical difficulties in the production of non-standard or 
custom made Products, it may cancel this Agreement without being liable to 
Distributor in any way.

         (e)  RETURN OF MATERIALS.  All trademarks, trade names, patents, 
copyrights, designs, drawings, formulas or other data, photographs, samples, 
literature, and sales aids of every kind shall remain the property of 
Manufacturer. Within thirty (30) days after the termination of this 
Agreement, Distributor shall prepare all such items in Distributor's 
possession for shipment, as Manufacturer may direct, at Manufacturer's 
expense. Distributor shall not make, use, dispose of or retain any copies of 
any confidential items or information which may have been entrusted to 
Distributor. Effective upon the termination of this Agreement, Distributor 
shall cease to use all trademarks, marks, and trade names of Manufacturer.

         (f)  LIMITATION ON LIABILITY.  In the event of termination by either 
party in accordance with any of the provisions of this Agreement, neither 
party shall be liable to the other, because of such termination, for 
compensation, reimbursement or damages on account of the loss of prospective 
profits or anticipated sales or on account of expenditures, inventory, 
investments, leases or commitments in connection with the business or goodwill 
of Manufacturer or Distributor. Termination shall not, however, relieve 
either party of obligations incurred prior to the termination.

         (g)  SURVIVAL OF CERTAIN TERMS.  The provisions of Sections 3(h), 5, 
6(g), 6(k), 6(l), 6(m), 8, 9, 10, 11, 12, 13 and 14 shall survive the 
termination of this Agreement for any reason. All other rights and 
obligations of the parties shall cease upon termination of this Agreement.

     9.  LIMITATION ON LIABILITY.  MANUFACTURER'S LIABILITY ARISING OUT OF 
THIS AGREEMENT AND/OR SALE OF THE PRODUCTS SHALL BE LIMITED TO THE AMOUNT 
PAID BY THE CUSTOMER FOR THE PRODUCTS.  IN NO EVENT SHALL MANUFACTURER BE 
LIABLE FOR COSTS OF PROCUREMENT OF SUBSTITUTE GOODS BY ANYONE, EXCEPT IN THE 
CASE OF DEATH OR PERSONAL INJURY RESULTING FROM MANUFACTURER'S GROSS 
NEGLIGENCE. IN NO EVENT SHALL MANUFACTURER BE LIABLE TO DISTRIBUTOR OR ANY 
OTHER ENTITY FOR ANY SPECIAL, CONSEQUENTIAL, INCIDENTAL, OR INDIRECT DAMAGES, 
HOWEVER CAUSED, ON ANY THEORY OF LIABILITY, WHETHER OR NOT MANUFACTURER HAS 
BEEN ADVISED ON THE POSSIBILITY OF SUCH DAMAGE.

                                   -11-


     10.  PROPERTY RIGHTS AND CONFIDENTIALITY

          (a)  PROPERTY RIGHTS.  Distributor agrees that Manufacturer owns 
all right, title, and interest in the product lines that include the Products 
and in all of Manufacturer's patents, trademarks, trade names, inventions, 
copyrights, know-how, and trade secrets relating to the design, manufacture, 
operation or service of the Products. The use by Distributor of any of these 
property rights is authorized only for the purposes herein set forth, and 
upon termination of this Agreement for any reason such authorization shall 
cease.

          (b)  SALE CONVEYS NO RIGHT TO MANUFACTURE OR COPY.  The Products 
are offered for sale and are sold by Manufacturer subject in every case to 
the condition that such sale does not convey any license, expressly or by 
implication, to manufacture, duplicate or otherwise copy or reproduce any 
of the Products. Distributor shall take appropriate steps with Distributor's 
customers, as Manufacturer may request, to inform them of and assure 
compliance with the restrictions contained in this Subsection 10(b).

          (c)  CONFIDENTIALITY.

               (i)  Distributor acknowledges that by reason of Distributor's 
relationship to Manufacturer hereunder, Distributor will have access to 
certain information and materials concerning Manufacturer's business, plans, 
customers, technology, and products that are confidential and of substantial 
value to Manufacturer, which value would be impaired if such information were 
disclosed to third parties. Distributor agrees that Distributor will not use 
in any way for Distributor's own account or the account of any third party, 
nor disclose to any third party, any such confidential information revealed 
to Distributor by Manufacturer. Distributor shall take every reasonable 
precaution to protect the confidentiality of such information. Upon request 
by Distributor, Manufacturer shall advise whether or not Manufacturer 
considers any particular information or materials to be confidential. 
Distributor shall not publish any technical description of the Products 
beyond the description published by Manufacturer (except to translate that 
description into appropriate languages for the Territory). In the event of 
termination of this Agreement, there shall be no use or disclosure by 
Distributor of any confidential information of Manufacturer, and Distributor 
shall not manufacture or have manufactured any compositions, devices, 
components or assemblies utilizing any of Manufacturer's confidential 
information.

               (ii)  Manufacturer acknowledges that by reason of 
Manufacturer's relationship to Distributor hereunder, Manufacturer will have 
access to certain information and materials concerning Distributor's 
business, plans, customers, technology, and products that are confidential 
and of substantial value to Distributor, which value would be impaired if 
such information were disclosed to third parties. Manufacturer agrees that 
Manufacturer will not use in any way for Manufacturer's own account or the 
account of any third party, nor disclose to any third party, any such 
confidential information revealed to Manufacturer by Distributor. 
Manufacturer shall take every reasonable precaution to protect the 
confidentiality of such information. Upon request by Manufacturer, 
Distributor


                                    -12-



shall advise whether or not Distributor considers any particular information 
or materials to be confidential. In the event of termination of this 
Agreement, there shall be no use or disclosure by Manufacturer of any 
confidential information of Distributor.

     11.  TRADEMARKS AND TRADE NAMES

          (a)  USE.  During the term of this Agreement, Distributor shall 
have the right to indicate to the public that Distributor is an authorized 
distributor of Manufacturer's Products and to advertise within the Territory 
such Products under the trademarks, marks, and trade names that Manufacturer 
may adopt from time to time ("Manufacturer's Trademarks"). Distributor shall 
not alter or remove any Manufacturer's Trademark applied to the Products at 
the factory. Except as set forth in this Section 11, nothing contained in 
this Agreement shall grant to Distributor any right, title or interest in 
Manufacturer's Trademarks. At no time during or after the term of this 
Agreement shall Distributor challenge or assist others to challenge 
Manufacturer's Trademarks or the registration thereof or attempt to register 
any trademarks, marks or trade names confusingly similar to those of 
Manufacturer.

          (b)  APPROVAL OF REPRESENTATIONS.  All representations of 
Manufacturer's Trademarks that Distributor intends to use shall first be 
submitted to Manufacturer for approval, which shall not be unreasonably 
withheld, of design, color, and other details or shall be exact copies of 
those used by Manufacturer. If any of Manufacturer's Trademarks are to be 
used in conjunction with another trademark on or in relation to the Products, 
then Manufacturer's mark shall be presented equally legibly, equally 
prominently, and of greater size than the other but nevertheless separated 
from the other so that each appears to be a mark in its own right, distinct 
from the other mark.

     12.  PATENT, COPYRIGHT, AND TRADEMARK INDEMNITY

          (a)  INDEMNIFICATION.  Distributor agrees that Manufacturer has the 
right to defend, or at Manufacturer's option to settle, and Manufacturer 
agrees, at Manufacturer's own expense, to defend or at Manufacturer's option 
to settle, any claim, suit or proceeding brought against Distributor or 
Distributor's customers on the issue of infringement of any United States of 
America or foreign patent, copyright or trademark by the Products sold 
hereunder or the use thereof, subject to the limitations hereinafter set 
forth. Manufacturer shall have sole control of any such action or settlement 
negotiations, and Manufacturer agrees to pay, subject to the limitations 
hereinafter set forth, any final judgment entered against Distributor or 
Distributor's customer on such issue in any such suit or proceeding defended 
by Manufacturer. Distributor agrees that Manufacturer at Manufacturer's sole 
option shall be relieved of the foregoing obligations unless Distributor or 
Distributor's customer notifies Manufacturer promptly in writing of such 
claim, suit or proceeding and gives Manufacturer authority to proceed as 
contemplated herein, and, at Manufacturer's expense, gives Manufacturer 
proper and full information and assistance to settle and/or defend any such 
claim, suit or proceeding. Manufacturer shall not be liable for any costs or 
expenses incurred without Manufacturer's prior written authorization.


                                  -13-



          (b)  LIMITATION.  Notwithstanding the provisions of Subsection 
12(a) above, Manufacturer assumes no liability for (i) infringements covering 
completed equipment or any composition, assembly, circuit, combination, 
method or process in which any of the Products may be used but not covering 
the Products when used alone; (ii) trademark infringements involving any 
marking or branding not applied by Manufacturer or involving any marking or 
branding applied at the request of Distributor; or (iii) infringements 
involving the modification or servicing of the Products, or any part thereof, 
unless such modification or servicing was done by Manufacturer.

          (c)  ENTIRE LIABILITY.  THE FOREGOING PROVISIONS OF THIS SECTION 12 
STATE THE ENTIRE LIABILITY AND OBLIGATIONS OF MANUFACTURER AND THE EXCLUSIVE 
REMEDY OF DISTRIBUTOR AND DISTRIBUTOR'S CUSTOMERS, WITH RESPECT TO ANY 
ALLEGED INFRINGEMENT OF PATENTS, COPYRIGHTS, TRADEMARKS OR OTHER 
INTELLECTUAL PROPERTY RIGHTS BY THE PRODUCTS OR ANY PART THEREOF.

     13.  INDEMNIFICATION.

          (a)  Manufacturer and Distributor each agree to indemnify and hold 
the other party harmless from and against any and all claims made by any 
person or entity arising out of the processing, marketing, distribution and 
sale of the Products, where and to the extent such damages have been caused 
by the fault of such party or its employees or agents. The indemnifying party 
shall have the right to defend or, at its option, to settle such claims, and 
if it chooses to exercise such right, it shall have control over any such 
claim or settlement negotiations. The indemnifying party shall be relieved of 
the foregoing obligations unless the indemnified party gives prompt notice in 
writing of any such claim, suit or proceeding and, at the indemnifying 
party's expense, gives the indemnifying party proper and full information and 
assistance to settle and/or defend any such claim, suit or proceeding.

          (b)  Distributor shall indemnify Manufacturer in respect of any 
claim which may be made against the Manufacturer.

               (i)  that the use to which the Products are put constitutes a 
     breach of Section 6 of The Health and Safety at Work Act 1974 or any 
     other relevant United Kingdom or overseas safety legislation; and/or

               (ii) arising out of the failure by the Distributor to observe 
     the terms of the Agreement.

The provisions of this Section 13(b) shall not apply where the claim arises 
as a result of the negligence of Manufacturer or use of the Products in 
accordance with Manufacturer's written instructions.


                                   -14-



     14.  GENERAL PROVISIONS


          (a)  GOVERNING LAW AND JURISDICTION.  This Agreement shall be 
governed by, and construed and interpreted in accordance with, the laws of 
the State of California, United States of America, without reference to 
conflict of laws principles or statutory rules of arbitration. The federal 
and state courts within the State of California, United States of America 
shall have exclusive jurisdiction to adjudicate any dispute arising out of 
this Agreement. Distributor hereby expressly consents to (i) the personal 
jurisdiction of the federal and state courts within California, (ii) service 
of process being effected upon Distributor by registered mail sent to the 
address set forth at the beginning of this Agreement, and (iii) the 
uncontested enforcement of a final judgement from such court in any other 
jurisdiction wherein Distributor or any of Distributor's assets are present.

          (b)  ENTIRE AGREEMENT.  This Agreement sets forth the entire 
agreement and understanding of the parties relating to the subject matter 
herein and merges all prior discussions between them. No modification of or 
amendment to this Agreement, nor any waiver of any rights under this 
Agreement, shall be effective unless in writing signed by the party to be 
charged.

          (c)  NOTICES.  Any notice required or permitted by this Agreement 
shall be in writing (in the English language) and shall be sent by telex, 
telecopier or telegram or by prepaid registered or certified mail, return 
receipt requested, addressed to the other party at the address shown at the 
beginning of this Agreement or at such other address for which such party 
gives notice hereunder. Such notice shall be deemed to have been given upon 
the earlier of receipt by the party to whom notice was sent or three (3) days 
after deposit in the mail.

          (d)  FORCE MAJEURE.  Nonperformance of either party shall be 
excused to the extent that performance is rendered impossible by strike, 
fire, flood, governmental acts or orders or restrictions, failure of 
suppliers, or any other reason where failure to perform is beyond the 
reasonable control of and is not caused by the negligence of the 
non-performing party.

          (e)  NON-ASSIGNABILITY AND BINDING EFFECT. A mutually agreed 
consideration for Manufacturer's entering into this Agreement is the 
reputation, business standing, and goodwill already honored and enjoyed by 
Distributor under Distributor's present ownership, and, accordingly, 
Distributor agrees that Distributor's rights and obligations under this 
Agreement may not be transferred or assigned directly or indirectly without 
the prior written consent of Manufacturer. Subject to the foregoing sentence, 
this Agreement shall be binding upon and inure to the benefit of the parties 
hereto and their successors and assigns.

          (f)  LEGAL EXPENSES.  The prevailing party in any legal action 
brought by one party against the other and arising out of this Agreement 
shall be entitled, in addition to any other rights and remedies that such 
prevailing party may have, to reimbursement for expenses incurred by such 
prevailing party, including court costs and reasonable attorneys' fees.


                                   -15-



          (g)  COUNTERPARTS.  This Agreement may be executed in two or more 
counterparts, each of which shall be deemed an original and all of which 
together shall constitute one instrument.

          (h)  PARTIAL INVALIDITY.  If any provision of this Agreement is 
held to be invalid, then the remaining provisions shall nevertheless remain 
in full force and effect. The parties agree to renegotiate in good faith any 
term held invalid and to be bound by the mutually agreed substitute 
provision.

     IN WITNESS WHEREOF, the undersigned are duly authorized to execute this 
Agreement on behalf of Manufacturer and Distributor, as applicable.


   METRA BIOSYSTEMS, INC.                      AMERSHAM K.K.
     ("Manufacturer")                         ("Distributor")

By:  /s/ George W. Dunbar, Jr.           By:  /s/ V. Chambers
   ---------------------------------        -------------------------------
Print Name:  George W. Dunbar, Jr.       Print Name:  V.M.A. Chambers
           -------------------------                -----------------------
Title:  President & CEO                  Title:  President
      ------------------------------           ----------------------------



                                   -16-






                                 EXHIBIT A

                  PRODUCT DESCRIPTION AND PURCHASE PRICE
                        For Research Products Only


                                                    Distributor's
                                                   Purchase Price
           Product(1)                              (U.S. dollars)
- -----------------------------------------          --------------

Collagen Crosslinks Immunoassay in
microtiter plate enzyme-linked
immunosorbent assay (ELISA)
format, including packaging,
labeling and product inserts                         $[500.00]

Prolagen-C-TM- Immunoassay in
microtiter plate sandwich-assay
format, including packaging, labeling             [to be determined]
and product inserts

NovoCalcin-TM- Immunoassay in
microtiter plate enzyme-linked
immunosorbent assay (ELISA)                       [to be determined]
format, including packaging, labeling
and product inserts

(1) Products to be sold by Distributor solely for research purposes.


   METRA BIOSYSTEMS, INC.                      AMERSHAM K.K.
     ("Manufacturer")                         ("Distributor")

By:  /s/ George W. Dunbar, Jr.           By:  /s/ V. Chambers
   ---------------------------------        -------------------------------
Print Name:  George W. Dunbar, Jr.       Print Name:  V.M.A. Chambers
           -------------------------                -----------------------
Title:  President & CEO                  Title:  President
      ------------------------------           ----------------------------



                                   -17-





                                 EXHIBIT B

                                 TERRITORY

Distributor's Territory shall be all portions of the following:


                                  [Japan]




   METRA BIOSYSTEMS, INC.                      AMERSHAM K.K.
     ("Manufacturer")                         ("Distributor")

By:  /s/ George W. Dunbar, Jr.           By:  /s/ V. Chambers
   ---------------------------------         ----------------------------
Print Name:  George W. Dunbar, Jr.       Print Name:  V.M.A. Chambers
           -------------------------                ---------------------
Title:  President & CEO                  Title:  President
      ------------------------------           --------------------------


                                   -18-





                                  EXHIBIT C

                       QUARTERLY PURCHASE COMMITMENTS
                         For Research Products Only

                                      First Year             Second Year
                                    Number of Kits          Number of Kits
                                    --------------          --------------
[Crosslinks]                        [to be agreed]          [to be agreed]
[Prolagen-C-TM]                     [to be agreed]          [to be agreed]
[NovoCalcin-TM]                     [to be agreed]          [to be agreed]







   METRA BIOSYSTEMS, INC.                      AMERSHAM K.K.
     ("Manufacturer")                         ("Distributor")

By:  /s/ George W. Dunbar, Jr.           By:  /s/ V. Chambers
   ---------------------------------        -------------------------------
Print Name:  George W. Dunbar, Jr.       Print Name:  V.M.A. Chambers
           -------------------------                -----------------------
Title:  President & CEO                  Title:  President
      ------------------------------           ----------------------------
                                                 1 May 1993


                                   -19-