8/12/2019 Kirschvink Iron Man Barinaga92

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NEUROBIOLOGYiving Personal MagnetismWhole New MeaningT i n y ~ a g n e t s o u n dn Human Brain MayCause Cancer That may sound like a head-line from the checkout counter of vour localsupermarket, but in fact it's not as far-fetchedas it seems. Earlier this week Caltechgeobiologist Joseph Kirschvink and his col-leagues Atsuko Kobayashi-Kirschvink andBarbara Woodford announced they had foundcrystals of the mineral magnetite in humanbrain tissue. Their results are in press, not inthe National Enquirer, but in the Proceedingsof the National Academy of Sciences.

Kirschvink vigorously plays down the can-

examine them under the electron microscope.When the researchers applied this method

to human brain tissue, they found magnetitecrystals of a size and shape that suggest theyare not con taminants but are formed by abiological process, says Richard Frankel, aphysicist who studies magnetite-containingbacteria at California Polytechnic Univer-sity in San Luis Obispo and has seen theCaltech samples.

If these particles are indeed part of thenormal brain, then Kirschvink will haveplunged smack into three controversial ar-

says Dean Astumian, a biophysicist at tNational Institute of Standards and Tecnology who has been studying the potentifor EMFs to cause biological effects. BAstumian says, that doesn't answer the maquestion that the skeptics raise: whether tweak magnetic or electrical signal will swamped by background "noise" in the ceNew background calculations must be donhe says, before that question can be answere

While the presence of magnetite in tbrain may not solve the EMF-cancer linkmay nevertheless help researchers understananother puzzle-the dark patches that apear in certain MRI images of brains and aapparently caused by the presence of iroSeymour Koenig, a biophysicist at t he IBWatson Research Center who studies tmolecular mechanisms underlying MRI cotrast, says Kirschvink is right in his conclsion that it must be iron in magnetic for

cer connection, but he does that causes the spots. Koeniconcede that the presence of and colleagues have shown thmagnetite in the human brain the iron-storage protein, fecould shed some new light on ritin, contains enough magnethe highly controversial ques- iron to "totally explain ttion of whether weak electro- quantitative results seen in immagnetic fields might have aging," but they hadn't idenbiological effects, including fied the magnetic material cancer. There are other im- the ferritin. Some of the maplications for the work as well, netite found by Kirschvinkand they are far from usual group may be from the ferrititabloid fare: the magnetite Koenig says.may help explain aberrant If magnetite does exist in thdark spots that show up in human brain, it isn't there some magnetic resonance im- cause cancer or put dark spots oages of human brains. And MRI images.mats it dointhen there is the matter of ures are 1 nanometers long. In magnetite-containing bactfuncti on- the magnet it e ria, the answer is simple: Magncould be merely a means of storing iron, or eas. The first concerns whether weak elec- tite crystals turn the bacteria into swimmipart of a magnetic sensing system, as it is tromagnetic fields (EMFs) from power lines compass needles that orient with respect to ththought to be in other organisms where mag- or appliances are capable of having biologi- earth'smagneticfield. Magnetite has also benetite has been found. Although the paper cal effects on humans. Controversial epide- found in animals that navigate by compamight have a bearing on these issues, its rela- miological studies have suggested that expo- direction, such as bees, birds, and fish. Btionship to them is speculative at best, ac- sure to EMFs is linked to some cancers, in- how-and even whether-magnetite is icording to every researcher who spoke to cluding leukemia and primary brain cancer volved remainsa mystery, since noone has yScience about the finding. "People are saying, (Science, 7 September 1990, p.1096; and 21 found neurons that contain or interact wi'That's interesting, but what does it mean ' September 1990, p. 1378 . Biologists have magnetite.says William Wisecup, executive director of also found that the fields have effects on In the magnetite-containing tissues the Bioelectromagnetic Society. mammalian cells in culture. But skeptics ar- birds, bees, and fish, the concentration of th

Kirschvink says it was the magnetic reso- gue that there is no known mechanism that mineral is a few orders of magnitude highnance imaging (MRI) results that inspired could link the EMFs and the observed effects. than it is in the human brain. Kirschvinhim to look for magnetite in human brains. I The magnet ite finding-if it's co n- suggests that while the magnetically wedid a back-of-the-envelope calculation," he firmed- could change those views. "Physi- endowed animals may turn out to use magnsays, and concluded that "the only way you cists have gone along for years assuming there tite as a navigational aid, for humans it ma[couldseesuchspots] swithmagnetite." U n- is not hi ng ferroma gne tic in huma ns," just be a vestigial remnant from our migrlike some people who scribble on envelopes, Kirschvink says. If there is nothing magnetic tory ancestors, or merely a way for cells Kirschvink was well positioned to check out in a tissue, then the only way the fields could store excess iron. After all, humans certainhis hunch. His group has led the way in search- affect it is by inducing very weak electrical aren't known for their capacity to navigaing for magnetite in animals, and has devel- fields inside the cells. But if the brain or other by sense alone, and experiments suggestioped ways of preparing tissue without con- tissues (which Kirschvink has not yet exam- any talent in that arena have been unpromtaminating it with iron fragments from surgi- ined) contain magnetite, it could interact ising and unrepeatable. So, in this area, as cal tools or magnetic dust particles-problems directly with weak magnetic fields, possibly the others, certainty remains elusive. "Wthat have plagued past studies. His group had making th e tissues more responsive to EMFs. don't know why [the magnetite] is there," halso found a means to fish the tiny magnetic "With magnetite there, you can detect a says. "All we know is that it is there."crystals out of homogenized brain tissue and field smaller than without magnetite there," -Marcia Barinag

SCIENCE VOL. 256 15 MAY 1992 96