EMFs and Alzheimer's
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Scary stitches? New evidence shows dressmakers and tailors may be at risk from high levels of EMFs produced by sewing machines. |
Scientists have implicated electromagnetic fields in several types of cancer, particularly leukemia, and have been warning in recent years of the risks of electromagnetic fields (EMFs) to those who work in electrical jobs. Results of two new studies, reported at the Fourth International Conference on Alzheimer's Disease, indicate that EMFs may also play a role in that affliction, which strikes an estimated 4 million Americans a year, and that those at the highest risk are not electrical workers, but dressmakers and tailors.
Eugene Sobel of the University of Southern California School of Medicine reported at the July 31 conference that a joint U.S.-Finnish team has found a strong association between EMF exposures and Alzheimer's disease, including evidence indicating that people with high occupational exposures to EMFs are at least three times as likely to develop Alzheimer's as those with low exposures. Sobel and colleagues also discovered that people in occupations in which they regularly use sewing machines may have the greatest risk of exposure, eclipsing the risk of electric power-line and cable workers. EMFs from industrial and home sewing machines were found to be as much as 200 milliGauss at knee level, although levels were much lower at the operator's head. David Savitz, an epidemiologist at the School of Public Health of the University of North Carolina at Chapel Hill and an expert on electromagnetic fields, cautions that it is not clear that the higher risk for these occupations is a result of higher exposure levels. Said Savitz, "I'm guessing that if you compared time-weighted, whole-body averages [of sewing machine operators] to a variety of electric utility workers, their exposure levels are probably in the same range. It's difficult to compare because different sources [of EMFs] have their own characteristics."
Sobel said that the significant relative risks for Alzheimer's disease are higher than those reported for leukemia and other types of cancer. The studies, which examined three sets of workers--two Finnish and one American--compared the occupational exposure levels of 386 Alzheimer's patients to those of 475 healthy control subjects. Subjects were classified into two exposure levels: medium to high exposure and low or no occupational exposure. The research team found that male workers with the highest exposure levels were three times as likely to develop Alzheimer's. Female subjects were shown to be at even greater risk, 3.8 times the normal risk, of developing the disease.
"This opens up a whole new frontier in terms of potential EMF effects,"said Louis Slesin, editor of Microwave News, in an article by the Associated Press. Said Slesin, "EMF has long been a backwater area with a lot of skeptical people taking potshots at the research. This could signal a major change in the way EMF health risks are addressed." Savitz warned that although the studies are certainly interesting, like all new information, they are in need of replication. Said Savitz, "The first link of this sort between a job title and a disease . . . is worthy of trying to refute or corroborate."
Scientists have yet to uncover what triggers Alzheimer's disease, which affects mainly people over 65 years old and causes memory loss, motor impairment, disorientation, personality changes, and eventually loss of bodily functions. Most researchers agree, however, that the cause is a combination of genetic, environmental, and possibly dietary factors.
Flexing Some Mussel
Zebra mussels have been the bane of businesses and boaters since they began infesting the Great Lakes almost six years ago, attaching themselves to boats and clogging water intakes and industrial pipes. Researchers, however, now say that although these zebras can't change their stripes, they may have some usefulness yet, as a yardstick to measure toxins in the environment and as filters of water pollutants.
Changing its stripes. Scientists are developing positive uses for zebra mussels.
Donald Lisk, a toxicologist at Cornell University, is working with colleague Edward Mills to develop a system for using zebra mussels to measure the presence of heavy metals, chemical toxins, and radioactive pollutants in the nation's water supply. According to Lisk, the freshwater mollusks are perfectly suited for the job for several reasons: heavy metals such as cadmium, nickel, and lead concentrate in mussel organ and muscle tissue, chemical toxins concentrate in the fatty tissues, and radioactive materials appear in the shell. All three types of pollutants are major environmental health problems in the Great Lakes and other areas. Scientists at the State of the Great Lakes Ecosystem Conference, a joint U.S.-Canadian meeting held in October, reported that hundreds of people still develop cancer every year from eating contaminated fish, accentuating the need for accurate measurement of pollutants.
A characteristic that makes zebra mussels efficient measuring tools is also one reason they have made many enemies: they attach themselves to underwater surfaces and stay there. Although this creates problems for boat owners and water systems, it enables scientists to get a consistent record of the level of contaminants in a given place. The mollusks, which typically measure about one inch across, are able to filter a liter of water a day. In a recent article Lisk said, "They're quite effective at filtering water and concentrating poisons. So what you have is a monitor that sits there and tells you what's happening."
Scientists at the Center for Great Lakes Studies and the University of Wisconsin in Milwaukee are excited about the mollusks' filtering abilities for another reason. In a laboratory experiment using zebra mussels to form a filter, the mussels reduced quantities of cryptosporidium by more than 95%. (Crytosporidium is a parasite that made hundreds of people sick last year when it contaminated Milwaukee's water system.) The zebra mussels also reduced coliform bacteria by 69%, most other bacteria in the water by 75%, and removed almost all particulate matter. Although the scientists conducting the experiment envision using full-scale zebra mussel filters at municipal water plants, there are currently no plans to implement the idea.
The environmental benefit of zebra mussels, however, may not outweigh the harm they cause to water systems, and the mollusks may inadvertently cause the introduction of even more contaminants to water supplies. Environmental officials estimate that the rapid spread of zebra mussels will cause up to $5 billion in property damage. Worse than that, say some, is the fact that currently the only effective means of controlling zebra mussels is to add chlorine or other chemicals into the pipes to kill the larvae before they attach, thereby introducing a new set of health concerns into the picture. Still, adds Lisk optimistically, until someone figures out a way to get rid of zebra mussels, we might as well make productive use of them.
Turning over a New Leaf
Reviled by doctors as the killer crop, targeted by antismoking activists, and investigated by Congress and the FDA for potential drug regulation, tobacco has become a popular nemesis in the past few years. New experiments suggest, however, that tobacco's nasty reputation may be cleaned up if the plant's promise as a medicine producer is fulfilled.
New life for the evil leaf? Tobacco's reputation may be redeemed if it becomes a viable producer of human proteins.
Although many of the almost 4,000 chemicals in tobacco are dangerous, others have beneficial or commercial use. For instance, scientists at North Carolina State University, in the country's top tobacco-producing state, are using tobacco plants to produce fraction-1, a protein produced by all green vegetables, but made in higher concentrations in tobacco. Although the first application of the gelatinous substance will probably be in cosmetics, researchers hope the protein may have potential as a nonallergenic infant formula or as an ultrapure food for kidney patients that may help them to avoid dialysis.
What has scientists truly excited about tobacco, however, is not so much the substances the plant produces naturally, but the medicines it may be engineered to make in the future, including blood thinners and possibly a drug to battle AIDS. Tobacco grows foreign genes so easily that scientists hope it may one day replace expensive transgenic animals and bacterial systems now being engineered to produce human proteins. "Tobacco is like the white mouse of the plant world," said Bob Erwin, president of BioSource Genetics, a new company investigating pharmaceutical tobacco, in an article by the Associated Press. Erwin has infected plants with transgenic viruses to produce a molecule called alpha-trichosanthin, which is being tested as a possible AIDS drug. The hope is that the plants will synthesize the substance in far greater amounts than humans synthesize it, making the drug more accessible and less expensive.
Plant pathologist Carole Cramer and colleague Deb Weissenborn of Virginia Technical Institute are conducting field trials at the Southern Piedmont Agricultural Experiment Station in Blackstone, Virginia, on tobacco plants bioengineered to express a bacterial gene used to produce a human anticoagulant. Cramer infected tobacco leaf with the bacteria and used it to grow dozens of transgenic plants producing the human blood protein. She is now extracting the protein and testing it to see if it has the same qualities as protein produced by humans. Although it may be years before any direct medicinal benefit is derived from tobacco, scientists are predicting that these new uses may be the savior of the small tobacco farmer and turn tobacco from an instrument of harm to an instrument of healing.
Cyber-schnoz
To find answers to difficult questions, people have, for years, been exhorted to follow their noses. Scientists seeking to understand how environmental toxins affect animals and people have taken this statement literally--well, almost. Researchers at the Chemical Industry Institute of Toxicology are using an innovative new tool--a computer-generated rat's nose--to study the effects of chemicals.
Toxicologists studying rat inhalation have found that how a chemical toxin affects an animal, or possibly a person, depends, in part, on where the chemical deposits in the respiratory system. Because inhalation studies are expensive and difficult because of the numbers of animals required, researchers began to look for another way to get the same information, thus the cyber-schnoz. Kevin Morgan, a biologist and veterinarian, and Julie Kimbell, who holds a Ph.D. in differential geometry, worked for five months at CIIT, a not-for-profit, industry-funded toxicology laboratory, developing a three-dimensional computer model of the inside of a three-month-old rat's right nostril.
Using the finite elemental method of solving complex geometrical equations and more than 600 slides of rat nasal passages, Morgan and Kimbell devised a model of the virtual reality nose that allows them to simulate air carrying environmental toxins throughout the nasal passages. So far, they have used the model to examine where chemicals such as formaldehyde and ozone deposit in the nasal passages. According to Morgan, they hope to eventually use the model to study all types of reactive gases, vapors, and particles. They hope to be able to extrapolate this information to tell how these chemicals may affect the human respiratory system.
Morgan and Kimbell use two different methods to judge the accuracy of the information generated by the computer nose. In the first method, they compare the uptake pattern of the distribution of formaldehyde generated by the computer with actual patterns of nasal lesions in rats exposed to formaldehyde. In the second method, photo developer is poured into a laboratory flow tank containing a geometric pattern on film which simulates the rat nasal passages. The rate of development of the film creates a pattern that the researchers can correlate with the computer simulation to test its validity. Regarding the rate of correlation, Morgan said, "We've found it to be extremely good."
Still, the "technose" has its limitations. For this reason, Morgan and Kimbell are working to develop human and rhesus monkey computer nose models. The human nose project used magnetic resonance imaging and CAT scans to generate the necessary coordinates. According to Morgan, who is working primarily on this project, they are now ready to begin constructing a model. The rhesus monkey nose model, being developed through a cooperative agreement with the EPA, is much further along. Kimbell has begun the first air flow tests on the rhesus monkey nose, which is much larger and much more similar to a human nose than the rat's. Said Morgan, "The monkey is a good intermediate between the rat and human." At least some laboratory rats can now breathe a sigh of relief.
Age-old Genetic Questions
Knowing that tumor incidence increases with age and that certain gene mutations are critical events in tumor formation, scientists have long supposed that genetic mutations leading to cancer increase with age. Until recently there was no direct evidence of this hypothesis, but researchers at the University of Southern California have now demonstrated that mutations in the oncogenes responsible for non-Hodgkin's lymphoma accumulate over the lifetimes of some individuals, perhaps putting them at greater risk for developing cancer.
Hazards of age. The accumulation of mutations in the BCL2 oncogene may account for the increased risk of non-Hodgkin's lymphoma in the elderly.
"Age is the single most significant risk factor for cancer, and the incidence of most cancers rises exponentially with age, said Gino A. Cortopassi, assistant professor of molecular pharmacology and toxicology at the USC School of Pharmacy who led the experiment, in an article by the Associated Press. Knowing that the incidence of non-Hodgkin's lymphoma increases over 40-fold with age, Cortopassi and colleagues used a technique called polymerase chain reaction to examine peripheral blood lymphocytes from 53 live patients and 31 autopsies, none of whom had non-Hodgkins lymphoma. The team was looking for translocation mutations in the BCL2 (B-cell leukemia/lymphoma-2) gene known to be associated with the disease. The mutations are found in about half of all cases of non-Hodgkin's lymphoma.
Although the researchers found that the frequency of BCL2 mutations is highly variable among individuals, frequencies of mutations in the BCL2 gene were, on average, 40 times higher in spleens and 13 times higher in lymphocytes of people over 61 years old compared with the those in people under 20 years old.
Other studies have shown that changes in expression of BCL2 prolong the survival of B-cells by delaying programmed cell death. In the Cortopassi study, two individuals were tested a second time five months after the initial test. They were found to still have the same translocation mutation, indicating that these cells can persis in the blood. Cortopassi and colleagues hypothesize that people who accumulate a heavy burden of BCL2 translocations over their lifetime may be at a higher risk for non-Hodgkin's lymphoma.
Researchers currently have two hypotheses as to how the mutations occur in the BCL2 gene in the first place. In humans, during normal development of the immune system, the DNA of B-lymphocytes is rearranged. Sometimes mistakes occur during this rearrangement in which DNA is translocated between the immunoglobulin gene on chromosome 14 and the BCL2 gene on chromosome 18. The first hypothesis is that challenges to the immune system, such as the infections, over a period of a person's lifetime may cause proliferation of cells containing preexisting BCL2 translocations. Alternatively, BCL2 translocations might occur more frequently as a result of exposure to environmental chemicals or radiation. The longer someone lives, the more likely they are to have such exposures. In a collaborative study with Cortopassi, Douglas Bell at the NIEHS found that the frequency of BCL2 mutations is significantly increased in the blood of heavy smokers, suggesting a link between BCL2 mutation and exposure. "However," said Bell, "for technical reasons, in these studies we can't really rule out either of these two mechanisms."
"It isn't clear why this particular change is occurring with age, said Philip Hanawalt, professor of biology at Stanford University. "The striking and important thing about the Cortopassi finding is that this is a known change in the gene, associated with a particular type of cancer, and it clearly is occurring as a function of age in normal humans that don't have the cancer."
Enforcing the Rules
The EPA announced November 30 that 1994 was a banner year in enforcement of the country's environmental regulations. According to a news release by the agency, the EPA set records in enforcement with 137 more actions than in 1993, and all while undergoing a reorganization of its enforcement office.
Milestones set by the agency were 2,247 actions against polluters including 220 criminal referrals to the Justice Department, up from 140 in the previous fiscal year; 403 civil judicial referrals, up from 338 in fiscal year 1993 and breaking the 1991 record of 393; and 1,597 cases seeking administrative penalties. All told, the agency collected $1.4 billion in Superfund cleanup commitments from liable parties and estimates that the government will collect $165.2 million in civil and criminal fines.
Industry and environmental groups are applauding the EPA for its strong showing, but caution that the upcoming reorganization of regional offices may derail some enforcement activities because regional staff are responsible for most enforcement-related activities. The new Office of Enforcement and Compliance Assurance is optimistic about continuing its high performance and has several initiatives in the works to make the enforcement process more efficient and more fair.
The agency has decided to review its existing policies on administrative penalties in an effort to make the policies consistent from one environmental statute to another and to emphasize multimedia enforcement. Although the agency may move toward an umbrella policy that treats all statutes the same, statute-specific concerns may make such a policy difficult to implement.
EPA staff are also seeking to use the agency's enforcement provisions in innovative ways to protect ecosystems. An ecosystem workplan is being developed and is expected to be a new focus for the reorganized enforcement office in 1995. The plan would allow the EPA to use multimedia compliance assistance on a broad range of ecosystem impacts. The plan is expected to target agricultural issues such as contaminated runoff and groundwater contamination, but will extend to other economic sectors as well. |
Last Update: May 21, 1998