See li I rt i Et ENE REEL CET eae ~ CANADIAN SCI ENCE Vaccine can be used for domestic pet sterilization By Carolyn Hoskins A novel vaccine than can tem- porarily sterilize male and female dogs for up to a year with only two injections may be on the market within 18 months. University of Saskatchewan researchers have applied for a U.S. patent for the vaccine, which so far has been effective in mice, rats, sheep and eattle, and is now under- going extensive trials in dogs. Professor Bruce Murphy, Direc- tor of the university’s Reproductive Biology Research unit, says the proposed injections will be con- siderably cheaper than spaying or castration and have the added ad- vantage that the sterility is rever- sible if the pet’s owner wants. Dr. David Silversides, a former graduate student of Professor Murphy’s, is largely responsible for the development of the product, in association with professors Reuben Mapletoft and ‘Vikram Misra. The vaccine fools the animal’s immune system into making an- tibodies against one of the animal’s own hormones, called gonadotropin-releasing hormone (GRH), that is.absolutely vital for the animal to reproduce. This hor- mone is normally present in the animal’s system all the time. Dr. Murphy says that previous researchers had tried injecting animals with the natural hormone (extracted from other animals) in the hopes that their immune systems would produce antibodies that would also attack their own GRH. But the hormone naturally varies ever so slightly in chemical structure, so antibodies against one variant of it wouldn’t necessarily attack others. So an animal could produce antibodies against ‘foreign’ GRH that wouldn’t affect its own. Dr. Silversides and his co- workers got around this by making a synthetic hormone and attaching it to a carrier compound. The carrier compound strongly alerts the animal’s immune system to the ‘foreignness’ of the injection, while the synthetic GRH is of a sufficien- tly general type that the animal produces an array of antibodies ef- fective’ against most varieties of GRH, including its own. These antibodies effectively eliminate the action of the animal’s GRH. So female dogs don’t come into heat, and males’ testes atrophy. In addition, the inhibition of GRH reduces certain ‘secondary’ sexual characteristics, such as aggressive behavior’ in male animals. In fact, the research was originally aimed at finding. an alternative to castration of bull calves in order to make them easier to handle. (Uncastrated bull calves are aggressive and temperamental, but castrated ones don’t grow as well in feedlots.) The researchers switched to domestic pets when funding was provided by Bayvet Division of Chemagro Ltd., a Toronto company that specializes in health products for animals. New kind of rubber really beats the heat By Lorraine Brown A new type of rubber developed at the University of Waterloo promises to reduce the frequency of oil well blowouts, make improved engine parts for small _high- performance cars, and possibly even make space travel safer in the future. The new product, called TOR- NAC rubber, has proven durable over a wide range of temperatures, and can withstand exposure to ultraviolet light, oil, ozone and other conditions normally destruc- tive to rubber. TORNAC rubber’s ability to withstand extremes of temperature will make it useful in producing parts—such as fan belts, gaskets, and hoses—for the hotter-running engines of small high-performance cars. The heat-tolerant rubber may also be used to produce more reliable seals for future space shut- tles and the space station. Dr. Gary Rempel, a professor of chemical engineering and Chairman of the Chemical Engineering Department at Waterloo, worked with chemists at Polysar Limited of Sarnia, Ontario to develop the catalyst used in producing the rub- ber. “The catalyst works as an entity within the rubber, ensuring that the rubber molecules are saturated with hydrogen atoms, similar to the way that butter is a saturated fat,’’ says Dr. Rempel. ‘‘An unsaturated rub- ber is prone to breakdown on ex- posure to ultraviolet light and ex- treme heat, whereas a saturated rubber is stable.’’ The rubber is called highly saturated nitrile (HSN) rubber because it contains compounds, called nitrile groups, that make it proof against oil, which normally makes rubber deteriorate. This trait will make the rubber useful for applications in the oil industry. Production of TORNAC rubber will begin in 1988. The rubber will be used to make high pressure seals, oil well blowout preventers, gaskets, diaphrams, hoses, tubing, fuel cells, and conveyor belts for hot or corrosive materials such as asphalt or oil sand. Dr. ‘Rempal says that TORNAC rubber shows promise for use in spacecraft because of its ability to withstand ozone, extreme tem- peratures and ultraviolet radiation. But more testing is needed to demonstrate its potential usefulness in space, he says. TORNAC rubber won a gold medal in the Canada Awards for Business Excellence in 1987, in the inventions category. The invention, credited to Dr. Rempel and _ his research associate Dr. Hormoz Azizian, is the process of producing the rubber, not the rubber itself. Patents have been granted in the U.S. and Canada, and applied for in 14 other countries. Dr. Azizian worked at Polysar for a few years, to oversee the trans- fer of the new technology to Polysar, under the Natural Sciences and Engineering Research Coun- cil’s Industrial Research Assistance Program (RAP). The research was also funded by Polysar, the On- tario government’s Board of In- dustrial Leadership and Development (BILD) program, and the National Research Council. (Canadian Science News) Castrated bull calves on feedlots suffer a loss of 16 per cent in their growth efficiency and must be given hormones to overcome this, says Dr. Murphy. Likewise, female cattle in feedlots are given male hormones to stop them from coming into heat, which disrupts their feeding. Dr. Murphy feels the vaccine should make it possible to suppress the undesirable behaviours in male and female cattle without having to treat them with additional hor- mones. The Saskatchewan group has already been granted a U.S. patent for a monoclonal antibody that causes early termination of pregnancy in dogs. In combination with two other antibodies, the product neutralizes hormones that are required to maintain a pregnan- cy and the mother’s body simply reabsorbs the embryos. Further work is now in progress to decide when is the best time to administer the antibody. This research was also funded by the Natural Sciences and Engineering Research Council un- der its co-operative research and development program, which en- courages collaboration with in- dustry. (Canadian Science News) Scientists study how quasars are born when galaxies collide By Pippa Wysong Quasars are made when galaxies collide and large amounts of matter start falling into a black hole, says a Canadian researcher who has been observing quasars through the Canadian-France telescope in Hawaii. The birth of a quasar, the brightest known object in the universe, is something that has piqued the curiosity of astronomers since the early 1960s. Quasars (short for quasi-stellar radio sour- ces) were first noticed in the early 1960s and were identified as very distant radio sources—on the order of 9 billion light years away. (One light-year is the distance that light travels in a year.) Dr. John Hutchings, an astronomer at the Dominion Astrophysical Observatory in Vic- toria, is part of a team of astronomers studying quasars. He says that quasars are intriguing because they can be used to ‘“‘study the structure of the whole uni- verse.”’ They are so far away that studying them is like looking back in time. Since it takes about 9 billion years for their light to reach Earth, astronomers are seeing back 80 per cent in time, back to when the universe was very young, Dr. Hutchings says. Astronomers have gradually been able to work out details of what quasars are like. At first, ‘‘they were just known as dots in the sky which appeared to be very distant,’’ Dr. Hutchings says. Eventually, astronomers worked out more details. ‘“‘If you look at them really carefully, you can see not just the bright dot, but a faint fuzzy galazy around it,’’ he adds. Although much smaller than a galaxy, quasars are about 100 times brighter and are located in the cen- tre of galaxies. Clues about how quasars are born were found while the astronomers were studying the structure of quasars and _ their surrounding galaxies. Quasars are found in the heart of a large galaxy that is interacting or colliding with another, smaller galaxy. When the galaxies collide, it “causes a lot of gas and maybe some stars to be disturbed out of their orbit and to fall into a central object,’’ Dr. Hutchings says. That object, located in the centre of a galaxy, is a black hole—a collap- sed, dead star so massive that not even light can _ escape its gravitational pull. Dr. Hutchings explains that there are two main types of quasars: radio-loud and radio-quiet. Radio- loud quasars are found in elliptical galaxies, while radio-quiet ones are in spiral-shaped galaxies. Scientists don’t yet know why the two types of quasars appear to be connected to two types of galaxies. However, the mechanism for their creation seems to be the same in each case—a large galaxy with a black hole colliding with a small galaxy. When galaxies collide, disturban- ces occur in the centre of the larger galaxy where the black hole is located. Dust and stars are stirred up and start falling into the black hole, accelerating because of the black hole’s intense gravity. As this mass of falling material gets closer to the black hole, its density and temperature increase dramatically, causing x-rays, bright light, radio waves, etc. So a quasar consists of material that is in the process of falling into a black hole. It is so bright because it is made up of the equivalent of an entire solar system being heated up and squeezed together. Dr. Hut- chings estimates the lifespan of a quasar at about 10 million years, the time needed for the material to fall into the black hole. When the process is over, the galaxy is left not with a burnt-out quasar, but with a larger black hole. For reasons that scientists don’t understand, quasars don’t seem to form when two large galaxies collide. ‘‘There’s a number of cases around in the sky that we know are two big galaxies smashing together and you may get some mild activity in the nucleus, but in general you don’t get a bright quasar,’’ Dr. Hutchings says. Astronomers are still investigating this. Dr. Hutching’s work has been supported by the National Research Council. (Canadian Science News) Biotechnology produces identical- twin test tube lambs in Guelph study Twin lambs Mutton and Jeff began life as the same embryo, but were microsurgically bisected six days after conception. The identical-twin lambs and seven others are the first animals born at the University of Guelph from bisected embryos. They are seen here with their surrogate mother, the sheep U2, and project director Dr. C. Gartley. (Photo: University of Guelph)