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Orono Weekly Times, Wednesday, May 22, 1991-15 Finding compounds that kéep eIIs from mâ"butating By Page Debergo, Two classes of compounds that appear to slow the rate of spontaneous mutation -of oeIl in the_ body have been discovered by researchers at thxe University of Alberta. Slowing the spontaneous mutation rate in humans could have effects on everything from curing cancer to extending people's life-span. Professor R.C. von Borstei, of U of A's faculty of genetios, is quick to point out that such long-term effects are still ini the reaimn of "science fiction", but says currenit research results are very encouraging. Mutant cei occur when 'mistakes' are made during the replication of DNA, which is responsible for inherited characteristies. Von Borstei says these mistakes are tied to what ho calis the three R's of DNA mtabolism. First, the chromosomes (strigs of genes) in celis can recombine improperly, resultîng in mutation. Second, nistakes can ho made when clis roplicate. Finaiiy, when the repair mechanisan tries to correct a mistakec it sometimes fails, ioaving a mutant cell. Wben a person grows older the mutation rate goes up. " probably because the body has accumuiated enough mistakes so that the replication, repair and recombination mechanismûs are flot as good as they once were, s0 they make even more mistakes,"* says von Borstel. A particular sot of genes in the body are responsibie for reguilating the rate of growth in clis; when they mutate, cancer occurs. von Borstol says. "Al of a sudden you mnutate those colIs and growvth is unreguiated, the cels just divide and divide." Von Borstel says, that many scientisis have been working on 'antimutagens' like vitamins E and C, Nvhich have a blocking effecî on some mutagens (substances that cause or increase mutation). "Antimutagens protoct you from the outside, they are an armour that you can put up between you and the things that cauise cancer. But the things inside the celI that cause cancer are mtîch more insidiouLs." Von Borstel developed a system tIo measuro the rate of spontaneous mutation accurately. Thon ho began tosîing various compounds' effect on the spontaneous mutation rate of yeast colIs. Yeast clis are commonly used in laboratories because they act much like human clis. So far, the, researchers have found two compounds that, iower the spontaneous mutation rate. One, a synthotic substance called acridine, "tends to drop the mutation rate to, about a third of the spontaneouLs mutation rate -- no matter how largo a dose you give the clis," says von Boritel. Thie other compound thec research team discovered was salit. "This was unexpoctod. Wo thought il ought to be a mut agen and il was, but then we wont to lowor and lower doses and al of a sudden the spontaneous mutation rate went precipitously down. It drops the [natural] rate by a factor of about five times, which is sizable" says von Borstel. "One of the strangost things about this effect is that salitat a vory low concentration causes more mutations. Thon it goes through this phase where il causes a much iowor rate and thon ail of a sudden when you givo too much you gel lots ofmutations," ho says. The concentration of salit that appears to lowor the spontan eous mutation rate of yoast colis is at a lovel siightiy higher than the concentration i sea waler. How this information translates into practîcal termas for a poison wanting to have the optimumn amount of sait in their diot isn't known yet because no rosoarch has beeni done with manunais. Tho researchers are setig up a study on the two oompounds' effeets on human oeils, and are iooking for othor compounds that affect the spontaneous mutation rate. They are also continuing to study acridine and sait to discover exactly how theso compounds affect the spontaneous mutation rate at ,a moiecular levol. Von Borstol says that they are now just beginning to understand how acridine works with DNA, but are a long way fromn understanding how saIt interacts with colis at a molecular level., Von Borstel's research was supported by the Natural Sciences and Engineering Research Council. (Caitadian Science News) Study examines, steroid use by high sechool kid's By David Helier Slightiy more than one per cent of Ontaio students aged 13 to 19 used- sleroids in 1989, according to a survey by the Addiction Research Foundation (ARF). The resulîs suggesl that about 9000 Onario high school and junior high school students use steroids. ,. Researchers Reg Smart and Ed Adlaf analyzed the responses to an anonymous questionnaire by 3,915 students in grades 7. 9. Il and 13 to produce the report on steroid use among adolescents. They found-that the typical steroid user was a young maie active in sports, particularly body-building and weight- lifting. MaIes were ten titnes more likeIy to use steroids than were femnales. Two per cent of the maies report steroid use, oompared with only 0.2 per cent of the females. The survey suggosts that steroid use aniong Ontario studonts is less than among studonts in the U. S. A recent U. S. survey showed that 6.6 per cent Coyotes spreadîng in eastern Canada By Lorraine Brown Coyotes are becoming a problemt for sheep farmers in Nova Scotia, but farmers are going 10 have to leam 1Io live with the animais, says Jenny Ryon, manager of the Dalhousie Universiy Animal Behaviour Research Station, a specialist in coyote and wolf behaviour. Coyotes have been movig steadiiy eastward for the Iast 100 years as f armers cleared land for agriculture. creating the animai's preferred habitat of open fields, At the saine time. the wolf, a competitor 10 the coyote, was being eliminated in eastemn Canada. The finit coyote was identified ài Nova Scotia in 1977. Sheep f armera wanted the governmnent to establishi bounties on the animals. But Ryon says bounties are not the mnswor. "Studies havo proven that only about thrcee 1 five per cent of coyotes kilI sheep," says Ryon. "Me bounty is indiscriminale. To make il work, huniers wouîd have 10 kili the right individuais -- the sheep kiliera." Furthermoro, when ýcoyote populations are unider stress from a pressure such as hunîing, they roact with a tremendousiy. stepped-up reproductive capaciîy, sho adds. "Biasting away ai them just makes themn produce that many more pups. It could even inecase the population." Not everyone agreos. hI Otario's Grey and Bruce Couinties, where coyotes have becomo a sovero probîcmn in recent yoars, local f armers report that consistent coyote hunting keceps shcep predation in check, says Miistry of Naitural Resources officer Blake Smith. Besides hunting, farmers can pursue a varieîy of other strategios. Electric fencing properly installed, cani cut -down predation by 85 per cent. Thec addition of a guard dog or donkey makes raids even bsslicy Donkcys bond 10 shccp trongiy. They don't 'like coyotes, and 1wýili kecp the animiaIs ai bay, cuting predation do\wnr another 10 per cent. Other det(errents include sirens and lights fiashing in tho barnyard, and poison shiccp cottars, which make coyotes violcntly ili and loslikely 10 aîîack afier the first expcience. Desý,pite farmers' distike of coyotes. Smnith and Ryon both, admit Io an admiration and affection for the animails. Smnith po(its out that coyotes play an important role in the overal balance of nature. "They keep raccoon and grotindhog populations under control.' and they dispiace foxes, thereby reducing the incidence of rabies," he says. "And orchard owýnera love coyotes, because they kilI mice and rabbits, which girdie and kilI their trees." In Ontario, there have been soveral reports of large, aggressive coyote-dog crosses,. knowvn as coy-dogs. But Ryon and Smith agreo that coy-dogs are not yet an issue. After hearing reports of huge coyotes, Smith asked local farmera to bring them ir to the MNR office. "So f ar, we haven't seen any," ho says. Ryon adds that the coy-dog is not yet a wcl-adapted animal. "The dog in these animais is not used to living outdoors and does not fit into the highly structured social systomn of the coyote," she said. 'Me specios is definitely undergoing rapid change as it adapts to ils newv situation in the cast. "Coyotes are gtting biggor, and their coats are changing as lhey intorbrood with dogs," says Smith. (Canadia,î Science NewtsJ of grade 12 maies have used steroids. says Adiaf. This was the firsî time the ARF Ontario Student Drug Use 'Survoy has inquired about steroid use. Tho survoy is conducted evory two years under the guidance and funding of ARF. Resuits of the 199 1 survey are duo oui in the faîl of 1991 and researchers at ARF are intorestedl in deîermining whother sîeroid use among studonts is on the risc or decreasing. Storoids, a largo and -diverse group of chemnical substances, include many hormones, vitamins and drugs. Some steroids occur naturaily in the human body, while othora are synthetically produced and used in the trealmont of numnerous disorders, such as asthma. One group of steroîds, called 'anabolic', promote the conversion of nutrionts into living tissue. During exorcise, naturaliy-occurring anabolic sîeroids direct the body to increase muscle mass. Over the last few decades. scientists have developed methods of synthoîically producing anabolic steroids thiat act like human anabolic steroids. However, though they may prom-ote the growîh of muLscletise these By SaUy Johnston New mothers may have an increased risk of suffering serious postpartum depression if they have a history of family- mental illness, suggests a University of British Columbia psychiatrist. Dr. Shaila Misri caried out a study of 50 women diagnosed as suffering depression after childbirth and found that the women who suffored severe posîpartum depression (requiring hospitalization mnd therapy) were most likely to have had family histories of psychiatric disordor. Womnen who had milder forms of, the problem did not synthetie seroids have unwanto-d side- effets. They can upsot other metabolie processes and sox hormone activities, poboniaiiy causing heart and liver disease, changes in sex drive and sexuial characteristics, and psychiatric problemis such as delusions, paranoia and ioss of emnotionai conîrol. The side-effects appear to vary dep)cnding on the specifie steroid uised and the dosage taken. The dose, quai ity and effet of any drug are unpredictabie whon it is taken without a physician's supervision. Concem over steroid use has tisen greatly in Canada sinco the 1988 Olymipics and the ensuing Dubini Enquiry into the illicit use- of perforrnanco-onbmncing drugs. Inlf 99 the federal govommont added anaboîjo steroids to its list of restrictod drugs, says Simart. The ARF suirvy indicated that 31 per cent of steroid-tL-ers ,injoct the dnîg. Hom-ever, oniy one stuident reported sharing needies, a practico associatcd Nwith a hligh risk of infection and transmission of diseases, including hepatitis and AIDS. The survey also found that users of steroids wero more likely to use have family histories of psychiatric problems. Altogether. 27 of the womnen had family histories of psychiatric disorders. Of these, 34 per cent had reportod depression in f irsi- or second- degroe blood relatives such as parent, grandparent, cousin, auint or uincle. Between 12 and 15 peýr cent of Canadian womnen suffer fromn postpartum depression. but- only a handfu-l seek, psychiatric help. Although it is ofien dismnissed, as 'baby blues', it is a serious clinicai iore With symptomfs ranging front tearfulness to threats of suicide. Other symptoms include fatigue. insomnnia, feelings of inadequacy and hopelessness,- irritability and the inability to care for the- infant. One patient, recalls Misri, had such a severe formn of postpartum dopression that she had to be hospitalized afier threatening to kilI hcer baby. The women who parlicipated in Misri's study were aged 25 to 40, with no previous history of depression reiated to childbirth. Ninety per cent of WANT ADS WORK Phone 983-5301 -~ aicohoi and tobacco, as well as illegal drugs such as cannabis and cocaine, than wero students who did flot use stcroids. Adlaf considors the profile of the steroid users a paradox. AIl students who reportod steroid use also reported involvement in a least one type of sports activity, which suggests steroid usera may bc heaith-conscious. Hovever, steroid use is a heaith hazard, and the ARF survey found that most steroid usersalaso report using other harmnfui substances. it may be that individuais use steroids primnarily for cosmetic pur-poses --dcveioping a 'btter physique' an d consider hoalth secondary in importance to appearance. the researchers speculate. Thie sur-vey did not ask whether the suibjecîs were inivolved in teain or other competitive sports. The researchems thorefore can't say whoîher the "wîn at any cost" ethos which has appeared in inquiries into drug use among elite and professional athietes vas motivating somo of the students Io tise steroids. (Canadian Science News) Postpartum depression Iink to, previous psychiatric history The sîudy also indicated that. almost haîf the wvomen 'intoérvieved had experienced a previous episode of psychiatric illness. 0f these, 30 per cent hlad sufferod depression. Misri, director ofthe psychosomatic obsttrics/gynecology clinic aI the universitys Grace Hospital, says the findings support her observations of patients attending the clinic. , "What we hope is that women like this, with a genetic prédisposition 10 depression, ill ho identifiod amd trcated as high risk during and after clildbirih, jusl as they are- ith diabetes and high bkood pressure." says NMisri. 'Il's a 'problem lthat ofton gels ignored and the attitude is one of 'pull yourself together'." Though "nobody knows" what physiological mechanism causes poslpartum depression, il secms 10 ho triggored by major hormonal changes foîlowing childbirth, says Misri. The disorder may appear as soon as two weeks amd as late as nine months afler giving birth. Other factors cmn spark postpartumi depression, including marital probiems and Iack of family support. Moisri advises women to talk 10 their famiîy physician about their emotional weli-being when a child is bom. Womnen suffering from postpartum depression can ho treatod with supportive psychotherapy, group therapy and antideprossant medication, sho says. (Canadian Science News) Af f ordable Dream Vacations! " Free Vacation Planning Services, " Discount Cruises 0 Charter Vacations " Airline Tickets * Honeymoon -Packages e Hotel and Car Reseir,atiqns PERSONAL& CORPORATE TRAVEL SERVICES Travel Agents International We Ire with you aul the way 68 KING ST. E., BOWMAN VILLE Over 300 Agencies in North Amenica 623-6690