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                                                                    Exhibit 28.8


[DEPARTMENT OF HEALTH & HUMAN SERVICES LOGO]

                                                    Food and Drug Administration
                                                    9200 Corporate Boulevard
                                                    Rockville MD 20850

Jun 16 2000

Mr. Oscar J. Sanchez
Vice President, Development and Engineering
Chad Therapeutics, Inc.
21622 Plummer St.
Chatsworth, CA 91311

Re:  K000890
     OXYMATIC Model 401
     Regulatory Class: II (two)
     Product Code: 73 BZD
     Dated: March 17, 2000
     Received: March 20, 2000

Dear Mr. Sanchez:

We have reviewed your Section 510(k) notification of intent to market the
device referenced above and we have determined the device is substantially
equivalent (for the indications for use stated in the enclosure) to legally
marketed predicate devices marketed in interstate commerce prior to May 28,
1976, the enactment date of the Medical Device Amendments, or to devices that
have been reclassified in accordance with the provisions of the Federal Food,
Drug, and Cosmetic Act (Act). You may, therefore, market the device, subject to
the general controls provisions of the Act. The general controls provisions of
the Act include requirements for annual registration, listing of devices, good
manufacturing practice, labeling, and prohibitions against misbranding and
adulteration.

If your device is classified (see above) into either class II (Special
Controls) or class III (Premarket Approval), it may be subject to such
additional controls. Existing major regulations affecting your device can be
found in the Code of Federal Regulations, Title 21, Parts 800 to 895. A
substantially equivalent determination assumes compliance with the Current Good
Manufacturing Practice requirements, as set forth in the Quality System
Regulation (QS) for Medical Devices: General regulation (21 CFR Part 820) and
that, through periodic QS inspections, the Food and Drug Administration (FDA)
will verify such assumptions. Failure to comply with the GMP regulation may
result in regulatory action. In addition, FDA may publish further announcements
concerning your device in the Federal Register. Please note: this response to
your premarket notification submission does not affect any obligation you might
have under sections 531 through 542 of the Act for devices under the Electronic
Product Radiation Control provisions, or other Federal laws or regulations.



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Page 2 - Mr. Oscar J. Sanchez

This letter will allow you to begin marketing your device as described in your
510(k) premarket notification. The FDA finding of substantial equivalence of
your device to a legally marketed predicate device results in a classification
for your device and thus, permits your device to proceed to the market.

If you desire specific advice for your device on our labeling regulation
(21 CFR Part 801 and additionally 809.10 for in vitro diagnostic devices),
please contact the Office of Compliance at (301) 594-4648. Additionally,
for questions on the promotion and advertising of your device, please
contact the Office of Compliance at (301) 594-4639. Also, please note the
regulation entitled, "Misbranding by reference to premarket notification"
(21 CFR 807.97). Other general information on your responsibilities under the
Act may be obtained from the Division of Small Manufacturers Assistance at its
toll-free number (800) 638-2041 or (301) 443-6597, or at its internet address
"http://www.fda.gov/cdrh/dsma/dsmamain.html".


                                   Sincerely yours,


                                             for [illegible]
                                   --------------------------------
                                   James E. Dillard III
                                   Director
                                   Division of Cardiovascular and
                                     Respiratory Devices
                                   Office of Device Evaluation
                                   Center for Devices and
                                     Radiological Health


Enclosure