How Clean is Too Clean?

November 1, 2014 by

Oct. 31, 2014

By Medical Discovery News

Cleaning supplies

Common knowledge and previous studies generally agree that children who grow up in the inner city and are exposed to mouse allergens, roach allergens, and air pollutants are more likely to develop asthma and allergies. But a recent study adds a new twist – children exposed to these substances in their first year of life actually had lower rates of asthma and allergies. However, if these allergens were first encountered after age one, this protective effect did not exist.

Another study parallels this one, concluding that children growing up on farms also have lower allergy and asthma rates. Scientists argue that farm children are regularly exposed to microbes and allergens at an early age, leading to this same protective effect.

Asthma is the most common chronic condition among children. One in five Americans, or 60 million people, has asthma and allergies. In the industrialized world, allergic diseases have been on the rise for more than 50 years. Worldwide, 40-50 percent of school-age children are sensitive to one or more common allergens.

In this study, scientists enrolled 467 children from the inner cities of Baltimore, Boston, New York City, and St. Louis and followed their health since birth. The infants were tested for allergies and wheezing by periodic blood tests, skin-prick tests, and physical exams, and their parents were surveyed. They also sampled and analyzed the allergens and dust in the homes of over 100 of the subjects.

Children who lived in home environments that included cat and mouse dander as well as cockroach droppings in their first year of life were much less likely to develop wheezing or allergies when compared to children who were not exposed to these substances. This protective effect was additive, so children exposed to all three were less likely to develop wheezing compared to children exposed to two, and those children were more protected than those who were exposed to only one. Only 17 percent of children who lived in homes with all three allergens experienced wheezing by age three, compared to 51 percent of children who lived in homes without such allergens. Interestingly, dog dander did not have a protective effect against the development of allergies or wheezing.

The richness of the bacterial populations children were exposed to enhanced this protective effect. This suggests that household pests may be the source of some of the beneficial bacteria in the inner city environment. Early exposure to allergens and certain bacteria together provide the greatest effect.

An infant’s microbiome, the total makeup of bacteria in and on their bodies, is developed during their first year of life. The bacteria colonizing an infant’s gastrointestinal system affects their immune system and influences the development of allergies. Scientists hypothesize that something similar may be happening in the airways and lungs, as kids with asthma have altered bacterial populations in their respiratory systems.

There is mounting evidence exposures to allergens and bacteria in the first few months of life help shape the respiratory health of children. But we don’t yet know how specific allergens and bacteria induce this protective effect, or how they can be used to treat children and reduce their chances of developing allergies and asthma.

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Warning: Third-hand Smoke

September 13, 2014 by

Sept. 5, 2014

By Medical Discovery News

Smoke

Science has long proven that smoking is bad for you and those around you, with 90 percent of lung cancer cases caused by smoking. Even second-hand smoke is dangerous enough to warrant banning smoking in public places. The idea of third-hand smoke premiered in 2009, and scientific evidence shows that it too can harm human health.

Third-hand smoke is the many toxic compounds from tobacco smoke that settle onto surfaces (particularly fabrics) such as carpet, furniture, and the inside of a car. Researchers have identified chemicals in third-hand cigarette smoke called NNA and NNK that can bind to DNA, a person’s genetic information, and cause damage and mutations that could lead to cancer.

There are 4,000 known pollutants in cigarette smoke including a large number that cause DNA damage. Many of them have been found in the carpets, walls, furniture, dust, clothing, hair, and skin of smokers long after they’ve smoked a cigarette. The pollutants from smoke can accumulate over time, making the environment increasingly toxic. Mainstream smoke has more than 60 known carcinogens, which cause cancer, and other toxins, many of which are present in second- and third-hand smoke. Nonsmokers are exposed to these toxic compounds when they inhale, touch, or ingest them off of surfaces containing third-hand smoke. To make matters worse, some of the smoke residue can undergo a chemical transformation into secondary compounds when it interacts with other indoor pollutants, like ozone and nitrous acid. For example, nicotine reacts with ozone in the atmosphere to produce byproducts and ultrafine particles that can trigger asthma attacks.

Other secondary products such as NNA and a related compound called NNK are also formed. A recent study aimed to discover what level of third-hand smoke mutagens and carcinogens a nonsmoker might be exposed to in realistic scenarios, and whether these levels would be high enough to cause damage to DNA or other adverse effects. Unrepaired DNA damage can lead to mutations and increase the risk of developing cancer. They concluded that human cells exposed to third-hand smoke or secondary compounds had increased DNA damage within 24 hours. These results provide evidence that third-hand smoke does include carcinogens from cigarette smoke and the environment. The study also showed that NNA and NNK have damaging effects on developing lungs, making them particularly harmful to infants.

Smokers themselves are giving off third-hand smoke toxins, so going outside to smoke helps but is no solution. It is unclear how long toxic third-hand smoke compounds continue to be a risk. Depending on the compound, they may linger for hours, days, weeks, or longer. When smokers quit they should take steps to rid their homes and vehicles of third-hand smoke. This is potentially a time-consuming and expensive proposition but it is worth doing.

In 2011, 44 million American adults smoked cigarettes and 34 million of them smoked every day. Smoking causes one in five deaths, killing nearly 500,000 people in the U.S. every year. That is more deaths than HIV, illegal drugs, alcohol, motor vehicle accidents, and firearms combined. Is it really worth it?

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Lifesaving Venom

September 1, 2012 by

By Medical Discovery News

Sept. 1, 2012

Reversing Cerebral Palsy

People have evolved a fear of snakes out of necessity. One bite from a venomous snake can prove fatal, so it’s ironic that a number of remarkable drugs are derived not only from poisonous snakes, but other deadly creatures as well. Researchers increasingly prize this group of animals, believing their venom holds the promise of effective treatments for major disorders ranging from high blood pressure to heart disease to cancer.

Depending on the type of poisonous snake, a bite can cause a drop in platelets and lead to uncontrollable bleeding. Or it can, like the venom of the Brazilian pit viper, incapacitate victims by causing their blood pressure to plummet. But in smaller doses these same characteristics can reverse disease.

One group of drugs, called ACE inhibitors, brings down blood pressure by decreasing chemicals that tighten blood vessels so that blood flows more smoothly. Another drug, called tirofiban, comes from the saw-scaled viper, which has venom that thins the blood and causes victims to bleed out. As a drug, it’s an anticoagulant used to dissolve blood clots in people with a minor or impending heart attack.

Another venom with similar mechanisms comes from the Malayan pit viper, except it also possesses a protein that may dissolve clots for as long as six hours after stroke symptoms start. An international study is targeting this venom’s potential to expand the three-hour window required for current drugs to be effective. Allowing people more time to get to a hospital for evaluation and treatment makes a significant difference on their prognosis.

Other deadly creatures also have lifesaving potential. Scientists are studying the fatal Deathstalker scorpion native to North Africa and the Middle East. Yet, its venom contains Chlorotoxin, which just happens to attach to cancer cells by binding strongly to a cancer-specific protein called matrix metalloproteinase-2. By fluorescently labeling Chlorotoxin, surgeons can easily identify cancer tissues and remove them. Scientists also figured out that by radioactively labeling Chlorotoxin, the toxin targets tumor cells and the radiation kills them.

Another example is Cobratoxin, which Western pharmacists began experimenting with as early as the 1930s on patients with diseases such as multiple sclerosis (MS) and asthma. More recently, a modified form of Cobratoxin has been shown to block the development of induced MS in 90 percent of lab rats. Cobratoxin seems to stimulate a molecule called interleukin 27, which slows an overactive immune response that scientists believe may be causing the disease. A related toxin molecule called Cobrotoxin has been shown in studies to impede the spread of HIV by blocking the receptors the virus uses to infect cells.

While the field of venom study has grown, researchers are concerned that negative environmental impacts on some of the threatened venomous species will limit their work. Ultimately that reduces the number of potential life saving or life changing drugs that are possible.

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