British biologists have found that unusual microparticles from magnetite, which were found in the brain of some people 20 years ago, do not arise naturally in its tissues, but get there from the exhaust gases of cars, penetrating into the brain through the olfactory nerves, says an article published in PNAS magazine.
In the early 90s of the last century, scientists made an interesting and at the same time alarming discovery - in the brains of people who complained of headaches, they found nanoparticles of magnetite, a mineral with magnetic properties. Their number was truly gigantic - there were approximately 5-100 million of these particles for each gram of brain tissue.
The discovery of particles with magnetic properties inside a living organism was not new to scientists - such crystals, as biologists believe today, are used by bacteria, fish and birds to operate their built-in "biocompass", which helps them navigate in space and look for a way to spawning grounds, nesting sites or sources food.
On the other hand, according to Barbara Meier of Lancaster University, such particles have never been found in the head of people, and later scientists began to doubt their "natural" origin when the links between magnetite particles and the development of a number of diseases were discovered. such as Alzheimer's disease.
Investigating these connections, Meyer and her colleagues tried to understand how these nanoparticles were formed by examining samples of magnetite crystals extracted from the brain tissue of 37 people who have recently died of natural causes or died in accidents in Mexico City, the capital of Mexico, and in British Manchester. …
The magnetic properties and structure of magnetite crystals, as Meyer explains, depend on the temperatures at which they formed. If magnetite is formed biologically, then these temperatures, for obvious reasons, are low and do not exceed 37-40 degrees Celsius. This makes it possible to distinguish biogenic nanocrystals from magnetite, which has arisen in the interior of the Earth or in the course of some abiogenic processes.
As it turned out, crystals of magnetite from the brains of the dead people formed at high, not low temperatures, which indicated their inorganic origin. Studying their shape with a microscope, scientists noticed that these crystals looked like spheres, and not polygons, like magnetite crystals from bacterial cells or bird beaks.
At this point, physicists remembered where they had already seen such crystals - such particles, as recent road studies show, are often found on the sides of roads, where they are deposited from the exhaust gases of cars. This is also supported by the fact that many nanoparticles extracted from the brain contained traces of platinum, which is used as a catalyst in the sensors of modern injection engines.
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Apparently, they are deposited not only in road dust, but also in the brains of pedestrians and drivers, where they penetrate, according to Meyer's assumptions, through the olfactory nerves, which directly connect the brain with the "outside world." Given that these particles either cause or exacerbate the development of Alzheimer's disease, scientists propose to conduct larger studies of their role in diseases of the brain and nervous system to determine how much of a danger they pose to us.