To­tal ban on pes­ti­cides un­re­al­is­tic: re­searcher


Spe­cial to The Com­pass

A lead­ing Cana­dian re­searcher says while cos­metic use of chem­i­cal pes­ti­cides should be banned, a to­tal ban on such prod­ucts is un­re­al­is­tic.

“Some farm­ers de­pend on them for their liveli­hood and without them their crop yields would be low...and in some poorer coun­tries, without pes­ti­cides, peo­ple would be dy­ing of malaria,” says Dr. Shawn Hay­ley who is study­ing the link be­tween en­vi­ron­men­tal tox­ins and Parkin­son’s Dis­ease.

In terms of the farm­ing in­dus- try, Dr. Hay­ley says looking at more or­gan­i­cally friendly prod­ucts should be the way of the fu­ture.

“But just to have a pretty lawn, I’d ban all chem­i­cal pes­ti­cides.”

No one knows what causes Parkin­son’s Dis­ease. How­ever, Dr. Hay­ley and other re­searchers across the coun­try are try­ing to find an­swers to that ques­tion.

Dr. Hay­ley is orig­i­nally from St. John’s and is a Memo­rial Uni­ver­sity grad­u­ate.

He now works as as­so­ciate pro­fes­sor and Canada Re­search Chair of Be­havioural Neu­ro­science at Car­leton Uni­ver­sity in Ottawa.

A neu­rode­gen­er­a­tive dis­ease, Parkin­son’s af­fects over 100,000 Cana­di­ans.

Move­ment is nor­mally con­trolled by dopamine, a chem­i­cal that car­ries sig­nals be­tween the nerves in the brain. When cells that nor­mally pro­duce dopamine die, the symp­toms of Parkin­son’s ap­pear.

Of­ten touted as the dis­ease where “your body turns against you,” many peo­ple with Parkin­son’s suf­fer from tremors, slow­ness and stiff­ness, bal­ance prob­lems, and rigid­ity of the mus­cles. Other symp­toms in­clude fa­tigue, soft speech, writ­ing prob­lems, stooped pos­ture, and de­pres­sion.

Dr. Hay­ley be­lieves that en­vi­ron­men­tal tox­ins such as chem­i­cals in some pes­ti­cides, in­sec­ti­cides and fungi­cides as well as heavy met­als in­clud­ing alu­minum, lead, iron, mer­cury, man­ganese and methyl mer­cury may lead to an in­creased in­ci­dence of Parkin­son’s.

“I’ve started to study the her­bi­cide Paraquat here in my lab,” Dr. Hay­ley says of the her­bi­cide that’s used in many parts of the world, in­clud­ing Canada.

Dr. Hay­ley’s re­search has found that, ad­min­is­ter­ing Paraquat to ro­dents de­stroys about 30 per cent of the dopamine neu­rons in the brain.

“Th­ese are the same neu­rons that die in Parkin­son’s and th­ese an­i­mals then show some slow­ness of move­ment sim­i­lar to Parkin­son’s pa­tients,” Dr. Hay­ley says.

Dr. Hay­ley’s re­search is now looking at ways the her­bi­cides could be killing th­ese dopamine neu­rons.

“We’re gath­er­ing ev­i­dence that ac­ti­va­tion of the in­flam­ma­tory im­mune sys­tem seems to be one im­por­tant player in this pathol­ogy,” he says.

In par­tic­u­lar, Dr. Hay­ley says, Paraquat causes an ac­ti­va­tion of spe­cial­ized brain cells called mi­croglial cells.

Th­ese cells are im­por­tant in fight­ing off in­fec­tion, he says.

How­ever, he says, Paraquat rec­og­nizes th­ese mi­croglial cells as for­eign cells, which causes the cells to be over-ac­ti­vated for long pe­ri­ods of time.

“This is caus­ing dam­age to oth- er­wise healthy neu­rons so those same de­fenses that are used to fight off in­fec­tions are killing healthy neu­rons,” he says.

Dr. Hay­ley’s re­search ex­plores why such dam­age is tak­ing place.

“It’s prob­a­bly not just one toxin that’s re­spon­si­ble for such a com­plex dis­ease as Parkin­son’s. It’s prob­a­bly a com­bi­na­tion of mul­ti­ple tox­ins over one’s life­time,” he says.

As well, Dr. Hay­ley says, there are likely ge­netic fac­tors that come into play in per­sons with Parkin­son’s.

Dr. Hay­ley is one of hun­dreds of Cana­dian re­searchers who have re­ceived fund­ing from the Parkin­son So­ci­ety of Canada.

His hope is that the re­search will lead to drugs that could help slow the pro­gres­sion of the dis­ease.

“Right now we’re sim­ply manag­ing the symp­toms,” Dr. Hay­ley says.

Dr. Hay­ley will hold a pub­lic lec­ture at the Health Sciences Cen­tre in St. John’s on Thurs- day, June 11 where he’ll dis­cuss his re­search link­ing en­vi­ron­men­tal fac­tors to Parkin­son’s dis­ease.

The Parkin­son So­ci­ety New­found­land and Labrador is host­ing the lec­ture.

“This is ex­cit­ing for us be­cause un­like many dis­eases, re­searchers have yet to de­ter­mine a cause for Parkin­son’s. To have re­searchers fo­cus on the en­vi­ron­ment gives us hope that per­haps a cause will be found,” says Pa­tri­cia Mor­ris­sey, ex­ec­u­tive di­rec­tor of the pro­vin­cial Parkin­son So­ci­ety.

The so­ci­ety will video-con­fer­ence Dr. Hay­ley’s lec­ture to Carbonear, Cor­ner Brook, Grand Falls-Wind­sor, Gan­der, Clarenville and Burin.

For more in­for­ma­tion on Dr. Hay­ley’s pre­sen­ta­tion call 709754-4428, toll free at 1-800-5677020 or by e-mail parkin­

Dr. Shawn Hay­ley works as as­so­ciate pro­fes­sor and Canada Re­search Chair of Be­havioural Neu­ro­science at Car­leton Uni­ver­sity in Ottawa.

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