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Biotech / Medical : VD's Model Portfolio & Discussion Thread -- Ignore unavailable to you. Want to Upgrade?

To: Cytokine1 who wrote (4173)	2/23/1998 8:44:00 PM
From: Rocketman	Read Replies (1) \| Respond to of 9719

Urine the Money Time was that the only consequence of drugs in urine was the confiscation of Olympic medals. Now, however, researchers have coaxed lab mice to produce a valuable pharmaceutical agent and in a way that makes it easy to harvest and to purify. Thanks to science that definitely qualifies as being of the "gee whiz" variety, the mice produce the drug in their bladders and simply turn it over to interested parties when they urinate. Transgenic animals that can produce pharmaceutical agents have been in the works for years, but the bioreactor organ of choice has been the mammary gland-useful drugs derived from animal milk are now in human clinical trials. The idea for trying the same with urine started when Tung Tien Sun of New York University Medical School published a paper in 1995 describing genes for proteins, called uroplakins, that get expressed only in the bladder. These uroplakins mesh together and probably have a role in maintaining a tidy lining, a highly desirable feature in a bladder. Kenneth D. Bondioli of the U.S. Department of Agriculture's Gene Evaluation and Mapping Laboratory read Sun's paper and realized that it might be worth trying to tack something useful onto a uroplakin gene. At this point. David E. Kerr and Robert I. Wall. also at the USDA'S gene lab, started shuffling genes. The aim was to get a useful human gene to hitch a ride on a uroplakin gene and find acceptance in the chromosomes of a fertilized egg. If they could pull that off, they could create a transgenic animal that produced the human gene's product only in the bladder, mixed up. of course, with the rest of the micturation. So it came to pass that the research team created transgenic mice, with the gene for human growth hormone riding the uroplakin gene appropriately designated UP2. And indeed, when this mouse tinkles, it leaves human growth hormone in the cup. (Actually, it does its business on the benchtop, which - take note, new parents with nice furniture-the researchers covered with Saran Wrap for easy collection.) Any commercial application for the bladder bioreactor would involve the creation of larger transgenic animals, such as cows, able to produce urine in buckets rather than thimbles. For this feasibility study, mice and human growth hormone make for a handy test system. "It was a two-pronged choice," says Wall. leader of the USDA group, who managed not to leak this work to the press prior to its publication in the January Nature Biotechnology. True, the molecule does have commercial application to treat dwarfism and potentially to enhance muscle strength in the elderly. More important for this first run, growth hormone gives itself away if any of it gets produced other than in the bladder-what transgenic researchers really do call leaky expression." Specifically, you get really big mice, easy to weed out via visual inspection. Harvesting drugs from urine is less oddball than it may appear. The widely prescribed drug Premarin, a type of estrogen, is collected from horse urine. And gonadotropins. used to enhance ovulation, come from the urine of human females. Urine has some distinct advantages over milk as a vehicle for pharmaceuticals. Number one, as it were, urine contains few proteins naturally, so purifying the product should be easier than purifying milk with its complex protein mix. Moreover, animals have to reach maturity to produce milk whereas they start making urine from birth. Finally, all animals, male and female, urinate. So don't be surprised if, down the road, pharmaceuticals derived from urine make a big splash. -SteveMirsky Scientific American March 1998