Jennifer Huber

Air Pollution Lurks Inside Your Home

photo of stir-frying — Photograph by kfisto via Creative Commons licensing.

How would you like a job that involves grocery shopping at Trader Joes with the company credit card and cooking dishes like stir-fry? This describes Tosh Hotchi’s job, but he isn’t a chef. He is part of a research team that studies how to build healthy efficient homes, including how to improve the quality of air inside a home through better ventilation. Hotchi is helping to study a major source of indoor pollutants – cooking.

When people think of air pollution, they usually picture a factory spewing a plume of toxic chemicals. But indoor air pollution causes significant health effects such as respiratory illness, asthma attacks, cancer and premature death. Californians spend over 45 billion dollars each year on these health impacts, according to a study by the California Air Resources Board.

Scientists at the Lawrence Berkeley National Laboratory (Berkeley Lab) have investigated which indoor air pollutants cause the greatest health consequences. In a paper published in Environmental Health Perspectives, they reported that fine particles with a diameter of 2.5 mm or less, formaldehyde and acrolein are the worst indoor contaminants for nonsmoking households.

Fine particulates are found indoors mainly due to cooking, burning candles or incense, and outdoor sources that leak inside. Formaldehyde is mainly emitted by materials used in home construction and furniture, such as particle board, paneling and foam insulation. Acrolein in the home is primarily from cooking, especially oils. All three of these contaminates also come from tobacco smoke.

“Think about what your putting in your home,” says Melissa Lunden, a Berkeley Lab staff engineer. “Most of us have to cook, but do you need the candles, incense and air fresheners? Freshening your air requires taking stuff out, not putting more stuff in.”

Berkeley Lab scientists are now looking for ways to improve indoor air quality, by developing better standards for residential buildings and new tests to measure these hazardous pollutants. Since cooking is a major source of indoor air pollutants, they have also evaluated the effectiveness of cooking exhaust hoods. Their study results showed that indoor air quality can be significantly improved by simply cooking on the back burners of your stove, using higher fan settings, and turning the fan on before you start cooking. Further research on cooking-induced pollutants is underway using a new demonstration kitchen to study real-life cooking conditions. During these studies, Tosh Hotchi’s stir-fry and cookies are just a happy bonus for his coworkers like Melissa Lunden.

For more information about indoor air pollution, check out my KQED Quest blog.

How Hot Will It Get?

Muir Glacer melt, Alaska. 1882 photo taken by G.D. Hazard; 2005 photo taken by Bruce F. Molnia. Courtesy of the Glacier Photograph Collection, National Snow and Ice Data Center/World Data Center for Glaciology.

Stay tuned for the next Science at the Theater, a free public lecture hosted by Lawrence Berkeley National Laboratory. It will be held on Monday April 22 at 7 pm at the Berkeley Repertory Theater.

Scientists will talk about their latest research findings on how the earth’s climate is changing, from the arctic to the rainforest. Participating speakers will address critical questions: What happens when the permafrost thaws? What do computer models predict about our future climate – floods, droughts, hurricanes and heat waves? What role do our forests play in carbon absorption? What kind of carbon tax might actually work?

Come find out what to expect and if there is anything you can do about it!

Nerve Stimulation May Prevent Migraines

Photograph of the Cefaly anti-migraine device, courtesy of STX-Medssprl via Creative Commons licensing — Photograph of Cefaly anti-migraine device, courtesy of STX-Med via Creative Commons license

While shopping for groceries at Trader Joes, suddenly your peripheral vision disappears. This could be frightening, but you know what is coming — a one-sided pulsating pain, sensitivity to light and noise, nausea, vomiting and seeing flashing lights. You quickly drive home and cancel your plans, because you have a migraine coming. You need to lie still in a dark quiet room for the next 24 hours.

Migraines affect about 30 million Americans. This means that one in four households in the US have at least one member impaired by migraines. Women are three times more likely to be migraine sufferers than men.

Unfortunately, there is currently no cure for migraines. A migraine diary can help identify the headache triggers to avoid. Medications can also help reduce the number of attacks or ease the symptoms, but these medications are often ineffective or cause unpleasant side effects.

Instead migraine sufferers might find relief from a new non-medicinal alternative, a device called a supraorbital transcutaneous stimulator (STS) that stimulates the nerves around the eyes and forehead. A study recently published in Neurology tested the safety and effectiveness of this STS device designed to prevent migraines.

Conducted by researchers in five specialized headache clinics in Belgium, this study was a randomized controlled trial that compared the STS device with an identical-looking sham device. Study participants were aged 18 to 65 who routinely experienced a minimum of two migraine attacks per month. None of the 67 participants had taken anti-migraine medications in the three months leading up to the study.

Both the STS and sham devices used a self-adhesive electrode placed on the forehead that buzzed identically during treatment. Only the STS devices delivered electrical impulses. The participants wore one of the devices for 20 minutes per day for 90 days.

The participants’ migraine diaries indicated that the number of migraine attacks dropped by at least half for 38% of the participants using the STS device, compared with 12% for those using the sham device. Although the severity of the migraines was not reduced, people using the STS device had fewer days with headache, fewer total migraine attacks, and used fewer pain relief medications each month. Most importantly, there were no adverse effects seen in either group.

The study concluded that treatment with a STS device is “effective and safe as a preventive therapy for migraine.” However, only 67 migraine sufferers have been studied and the use of this device was only examined for three months. Larger studies with longer-term treatment are needed to confirm that this STS device is safe and effective.

For more information about migraines and the STS device, check out my KQED Quest blog.

Dreaming of Sleep

woman laying in bed — Photograph courtesy of Wiros via a Creative Commons license.

You lay in bed, tossing and turning. Your body is exhausted, but your mind is racing with the day’s activities. Or worse yet, you’re stressing out about all the things on your to-do list for tomorrow.

Insomnia has become a major health concern worldwide with about 15% of the global population seeking relief with sleeping pills or tranquilizers. In the US, 60 million prescriptions for sleeping pills are issued each year. The most commonly prescribed type of sleeping pill is non-benzodiazepines, also called z-drugs — zaleplon (Sonata), zolpidem (Ambien), zopiclone (Imovane), and eszopiclone (Lunesta). However, a recent scientific journal article has raised some concerns about using these drugs.

Researchers from Harvard Medical School, the University of Connecticut and the University of London performed a quantitative statistical analysis of 13 studies on the effectiveness of z-drugs and their associated placebo response. They selected only randomized double-blind placebo-controlled trials, which means that neither the 4378 participants nor the researchers knew who was given the drug and who the placebo. They obtained the data from the US Food and Drug Administration, using both published and unpublished trials in order to avoid “publication bias.” Their research results were published in the British Medical Journal on December 17, 2012.

This large, well-designed study found that the z-drugs helped participants fall asleep more quickly, as measured subjectively by the participants and by equipment in a sleep lab. However, half the effect of the drug was found to be due to a placebo response. Specifically, participants on average fell asleep in the lab only 22 minutes faster if taking the z-drug compared to the placebo. This has raised concern on whether the benefits of taking z-drugs are worth the risk of adverse side effects, which include daytime fatigue, memory loss, problems with balance, dependency, and an associated risk of an earlier death.

Of course, how quickly you fall asleep is only one symptom of insomnia. Other important measures are the total sleep time, number of awakenings, sleep quality, and time spent awake after sleep onset. Although the study looked at these other outcomes, unfortunately there was insufficient data to make firm conclusions on these factors.

Hopefully there will be further research to analyze the effectiveness of z-drugs on all aspects affecting sleep quality. In addition, the demonstrated importance of the placebo response suggests that more attention should be directed at psychological interventions for insomnia.

For more information about z-drugs, check out my KQED Quest blog.

Think Before You Drink Grapefruit Juice

photograph of grapefruit — Courtesy of dullhunk via Wikimedia Commons

You follow the directions on your medication carefully, always taking the pills with the correct frequency and with or without food as directed. But have you discussed with your doctor or pharmacist whether ingesting grapefruit could cause an unintentional drug overdose?

A drug is normally metabolized in the gastrointestinal tract, but a liver enzyme called cytochrome P450 3A4 (CYP3A4) deactivates much of the drug so the body only absorbs about half of it. This process is taken into account when a doctor prescribes the necessary dose.

However, grapefruit, grapefruit juice, Seville bitter oranges (used in marmalade), limes and pomelos naturally contain chemicals called furanocoumarins. These furanocoumarins inhibit the CYP3A4 enzymes, causing the gut to absorb much more of the drug at a potentially toxic level. Sweet oranges, such as navel or Valencia, do not contain furanocoumarins.

This grapefruit-medication interaction was discovered back in 1989 by David Bailey, Ph.D., a clinical pharmacologist at the Lawson Health Research Institute. However, Bailey recently released an expanded list of medications affected by grapefruit in the peer-reviewed Canadian Medical Association Journal. The number of drugs that interact with grapefruit has significantly increased to more than 85 as new drugs have come on the market. More importantly, 43 of these drugs could interact with grapefruit and lead to serious side effects, such as kidney damage, blood clots, respiratory depression, abnormal rapid heart beats (torsade de pointes) and sudden death.

So it is important to carefully read the information leaflet that comes with your medications, as well as discuss with your doctor or pharmacist how your diet may affect your medication.

For more information about a potential drug overdose caused by ingesting risky citrus, please check out my KQED Quest blog.

Dynamic Duo: Antibiotics and Probiotics

Photograph of antibiotics. — Photograph of antibiotics, courtesy of sparktography via Creative Commons license.

When your cold or flu virus turns into a bacterial infection, taking antibiotics can seem like a miracle. You often start feeling better after just a day or two. Antibiotics work by killing bacteria or by stopping bacteria from multiplying. Antibiotics quickly make you feel better because the drug kills the majority of the targeted bacteria very quickly.

However antibiotics also kill beneficial bacteria and induce negative side effects — most commonly diarrhea, upset stomach, and vaginal yeast infection. For instance, antibiotics cause about one out of three people to get diarrhea by disrupting the balance of the intestinal flora, a collection of bacteria and other microorganisms in the digestive tract. This can result in an overgrowth of the Clostridium difficile bacteria that causes diarrhea. Similarly, antibiotics can disrupt the vaginal flora and cause an overgrowth of Candida yeasts to cause a yeast infection.

Probiotics are live bacteria, yeasts and other microbes intended to maintain or restore the supply of beneficial bacteria in the body, particularly the stomach and intestines. Probiotics are found naturally in certain foods, including yogurt, aged cheeses, kefir, miso, tempeh, and fermented cabbage. Dietary supplements are another common source of probiotics.

The use of probiotics to reduce antibiotic-induced side effects is now becoming more widely accepted by the medical profession. A recent study published in the Journal of the American Medical Association supports taking probiotics with antibiotics. A team of researchers from southern California combined and analyzed the results of 63 randomized controlled trials of probiotics for the prevention or treatment of antibiotic-associated diarrhea. The 11811 men and women included in this large combined study took a placebo or probiotics supplement along with their antibiotics. The people who took the probiotics were 42% less likely to develop diarrhea than those taking the placebo.

However, further research is needed to determine the most effective probiotics and dose. Of course it is also important to limit your use of antibiotics, using them only for bacterial infections when necessary.

For more information about using probiotics with antibiotics, check out my KQED Quest website.

Science Behind Vampire Folklore

CountDracula_BelaLugosi1931Dracula_CreativeCommons — Count Dracula as played by Bela Lugosi in the 1931 film Dracula, courtesy of Creative Commons license.

Legends of blood sucking creatures have existed for millennia. Why have people around the world always been so fascinated by vampires? Did vampire tales begin as a way to explain frightening phenomena that people actually witnessed? Although there is no scientific evidence for vampires, there is some scientific basis for vampire folklore.

The vampire has evolved over time in countless directions, moving in popular culture from a pure evil being to a conscience-bound but sexy seducer. The vampires of “Twilight” and “Vampire Diaries” act more human than Bram Stoker’s “Dracula.” However, in general vampires are predatory creatures in human form that survive by drinking the blood of the living through protruding fangs. They are potentially immortal but they can be killed by a stake through the heart, beheading and direct sunlight.

Many vampire behaviors can be explained by medical conditions, such as the rare blood disease porphyria. People with porphyria have an enzyme deficiency that interferes with the production of an important part of red blood cells, called heme. The skin of a porphyria sufferer burns, blisters and scars when exposed to sunlight, so they can only go out at night. This disease can also cause their mouth and urine to turn red, leading to the misbelief that they drink blood. And porphyria is hereditary, so there may have been concentrations of sufferers in certain areas throughout history.

Of course science can’t fully explain vampire myths. Some supernatural magic is required to do that, which is generally more entertaining. So dress up as a vampire on Halloween and just enjoy scaring everyone.

For more information about the science behind vampire folklore, check out my KQED Quest blog.

Should You Get a PSA Blood Test?

OlderManDraw_JointBaseLewisMcChord_Flickr — Photograph courtesy of Joint Base Lewis McChord via Creative Commons

My brother-in-law was seemingly the healthiest person I knew. He never even got a cold, so he rarely saw the doctor. Luckily he got a complete checkup when he turned 50, because it turned out that he had aggressive prostate cancer. Standard screening, to find prostate cancer in people who don’t have symptoms, allowed him to be treated in time.

Standard prostate cancer screening consists of a digital (finger) rectal exam to feel for prostate abnormalities and a simple blood test that measures the amount of prostate-specific antigen (PSA) in the blood. PSA is a protein produced by the prostate gland that is present in small quantities for healthy men, but it’s generally evaluated for men with prostate cancer and other prostate disorders. The goal of PSA screening is to detect prostate cancer early, so it is easier to treat and more likely to be cured.

So why has PSA screening recently become so controversial when it’s just a simple blood test? The main issue is that PSA screening isn’t good at distinguishing between aggressive life-threatening prostate cancer and slow-growing prostate cancer that may never spread. So it may lead to unnecessary side effects from overtreatment of slow-growing prostate cancer, including a risk of incontinence and impotence.

This controversy escalated in May 2012 when a government panel of health experts called the U.S. Preventive Services Task Force (USPSTF) recommended against PSA-based screening for prostate cancer for men of any age, stating that the benefits of screening don’t outweigh the harms of overtreatment.

The USPSTF based its recommendation primarily on the two largest published randomized clinical trials that evaluated the effectiveness of PSA screening. The first is the U.S. Prostate, Lung, Colorectal and Ovarian (PLCO) Cancer Screening Trial in which 76,685 men aged 55 to 74 years were randomly assigned to receive either annual PSA screening or “usual care.” The study found that slightly more prostate cancers were found in the PSA screened group, but the number of people that died from prostate cancer were about the same for both groups. Hence, it raised the question of whether men were harmed from overtreatment of cancers that weren’t life threatening. However, this PLCO study is inherently flawed because 52% of the “usual care” control group also received PSA screening and 40% of the study participants received PSA screening before enrollment in the trial. Since so many men in the “usual care” control group received PSA screening, it’s not surprising that the prostate cancer mortality rates were the same for both groups.

The USPSTF also based its recommendation on the European Randomized Study of Screening for Prostate Cancer (ERSPC) that randomly assigned 162,243 men aged 55 to 69 years to either PSA screening once every 4 years or an unscreened control group. After correcting for patients that did not follow the protocol-prescribed screening procedures, the ERSPC found that PSA screening actually reduced the risk for dying of prostate cancer by 31%. Many argue that this demonstrates that PSA screening has a significant benefit, so it’s unclear how the USPSTF considered these results in their benefit to harm analysis.

An ad hoc group of nationally recognized prostate cancer medical experts have argued against the USPSTF recommendations. They state, “We believe that eliminating reimbursement for PSA testing would take us back to an era when prostate cancer was often discovered at advanced and incurable stages.”

A journal article published in the July 2012 issue of Cancer supports the view of this ad hoc group. Researchers at the University of Rochester Medical Center used data from the Surveillance, Epidemiology and End Results Program to estimate the total number of men in the current U.S. population who would have metastatic prostate cancer at initial diagnosis if PSA screening weren’t used. Such metastatic prostate cancer is usually rapidly fatal with a median survival of less than 1 yr to 2.6 years, depending on age. The study found that there would have been 25,000 men presenting with metastatic disease in 2008 in the absence of PSA-screening, instead of the 8,000 men that were actually observed using PSA-screening.

So the uncertainty and controversy about PSA screening continues despite extensive research. Since I work in the field of prostate cancer research, friends and family members have asked my opinion. It seems to me that the new screening guidelines against PSA testing assume that ignorance is less stressful than having faith in your doctor; specifically, it’s better to not even perform a simple PSA blood test because patients with low PSA levels are often over-treated. Why not just change how to treat patients with low PSA levels and repeat the blood test in 6 months to a year to see how quickly the PSA level rises — since prostate cancer is more likely to cause a rapid rise in PSA levels? Is this common practice of “watchful waiting” by your doctor really more stressful than not having the blood test at all? For some, that simple blood test could also indicate that you have aggressive prostate cancer that has spread and needs immediate treatment.

For more information about PSA screening, check out my KQED Quest blog.

Stem Cells Cause Clogged Arteries

illustration of how the newly discovered vascular stem cells can become smooth muscle, fat, cartilage or bone cells. — Within the walls of blood vessel are smooth muscle cells and newly discovered vascular stem cells. These stem cells are able to differentiate into smooth muscle, fat, cartilage and bone cells. (Song Li illustration)

Odds are that you know someone who’s had a heart attack. If you’re like me, you know many. One American suffers a coronary event every 25 seconds and about every minute someone dies from one.

Doctors thought they understood artery-hardening diseases that lead to heart attacks, strokes and death. But these theories have been contradicted by new research performed at the University of California, Berkeley. According to a new study published in Nature Communications, a previously unknown type of stem cell is actually the underlying cause for clogged arteries.

Researchers analyzed cells from blood vessels of transgenic mice and humans. They were able to trace the lineage of the cells that rapidly reproduced to cause a build up of fibrous scar tissue in the vessel walls. Current theories predicted these would be smooth muscle cells but instead they were a newly discovered type of stem cell.

Specifically they determined that the culprit behind clogged arteries are multipotent vascular stem cells that can develop into various specialized cells – smooth muscle, nerve, cartilage, bone and fat cells. This explains how arteries can calcify and harden, since the stem cells can form bone and cartilage.

If this research is verified in animals and humans by other research groups, this could lead to new therapies.

For more information about this research, check out my KQED Quest blog.

Curiosity and Nervousness over the Mars Landing

Artist's concept animation depicting the moment that NASA's Curiosity rover touches down onto Mars. — Artist’s animation depicting the moment that NASA’s Curiosity rover touches down onto Mars. (NASA/JPL-Caltech image)

When I tried to make lunch plans with a friend for next week, he didn’t know yet whether he could meet me. That’s because his plans depend on how smoothly the Curiosity rover lands on Mars tonight. His research team put together the Radiation Assessment Detector that is mounted on the top deck of the Curiosity rover.

NASA’s Mars Science Laboratory spacecraft with the Curiosity rover are approaching Mars at this moment. It’s expected to land tonight at 10:31 p.m. PDT (Pacific Daylight Time). The technical challenges involved in the Curiosity’s landing are daunting. The final minutes to landing are described beautifully in the NASA Jet Propulsion Laboratory’s popular video dubbed “The Seven Minutes of Terror.”

We still aren’t sure if life ever existed on Mars. From past missions, researchers know that there used to be water there. Now they want to determine if Mars once had the kind of environment that could be habitable or conducive for the formation of microbial life.

The Curiosity rover is a car-like rover that will search Mars for past or present conditions favorable for life on the planet. It is basically a science lab on wheels, including 10 complex scientific instruments. These instruments are designed to study the chemistry of rocks, soil and atmosphere — searching for signs of past life on Mars.

One of those scientific instruments is the Radiation Assessment Detector, which is designed to characterize the energetic particle spectrum at the surface of Mars. This will allow researchers to determine the radiation dose for humans at the planet surface, as well as provide input on the effects of particles on the surface and atmosphere. The surface is thought to have much higher radiation than Earth, since Mars has a thinner atmosphere and no global magnetic shield to divert charged particles.

Although all research requires patience, hurling your research instrument at a far away planet requires both patience and guts. The landing may cause 7 minutes of terror, but the days of waiting must include its own nail-biting nervousness. When I get together with my friend for lunch, I’ll check his nails. Hopefully the landing will be a success, so he’ll be at the Jet Propulsion Laboratory for the next couple weeks though. I can wait.

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