T H E N I H C A T A L Y S T | N O V E M B E R - D E C E M B E R 1 9 9 8 | ||
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VETERINARY
RESOURCES |
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Until last year, when the Veterinary Resources Program (VRP) was moved into the Office of Research Services (see "ORS," page 1), only animal models maintained by the NIH Animal Genetic Resource (NIHAGR, see below) were cryopre-served and banked. Since then, however, intramural investigators from NCI, NIMH, NHLBI, NIDDK, NIDR, CBER, and NIA have availed themselves of the service.
"We have the responsibility," Rall said, "for banking the embryos and distributing them"a service, he added, that not everyone on campus is aware of. "Investigators reach a point where there's no more room in the animal room, and then they realize they must bank the models they're not using." The place to turn to, of course, is the VRP. Investigators are "charged by the actual effort," Rall said; donor females are superovulated with the aim of generating large numbers of embryos. "Sometimes only a fraction produce embryos," however, because "the science is imperfect. We can estimate, based on genetic background and experience, whether it will be a problem."
At the moment, 500 frozen embryos are stored in straws,
up to 20 per straw, in a liquid nitrogen refrigerator (at -1960
C) in a building on campus and at a similar facility in Gaithersburg,
Maryland. Most are eight-cell mouse embryos; some are rats; and fewer
are rabbits. Since 1980, when the Embryo Cryopreservation Program was
established, more than 250,000 embryos from 300 mouse, rat, and rabbit
genotypes have been cryopreserved and banked.
Cryopreservation is one component of the NIHAGR, which has created "hundreds of animal models for investigators, mostly inbred strains and con-genics (inbred strains carrying spontaneous mutations), and have begun incorporating transgenic and knockout models into the program," Rall said, noting that embryo collection and cryopreser-vation of the poorly reproducing immuno-compromised NIHAGR models is quite challenging. The NIHAGR serves commercial breeders all over the world, he added: "It's, in effect, an international resource. This means that our investigators can buy from commercial breeders and know that the genetics meets high standardsNIHAGR standardsand that these companies will vary only on service and quality control. The end result is reduced animal costs for NIH," Rall said. Sixty percent of the world's research animals, he added, can trace their ancestors to the NIHAGR colonies. For more information about VRP cryopreservation services, contact William Rall at 496-0468. |
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