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A.
Breastfeeding Reduces the Risk of Childhood Leukemia
Narrator: This is Science Today. Babies who are breastfed have a lower risk of developing childhood leukemia. This according to an analysis conducted by Marilyn Kwan, a researcher in epidemiology at the University of California, Berkeley.
Kwan: We looked at breastfeeding duration – both short-term, which is less than six months and long-term breastfeeding, greater than six months. And we did find a protective association between breastfeeding less than six months and risk of childhood leukemia, specifically the most common subtype, acute lymphoblastic leukemia.
Narrator: It's believed childhood leukemia may be an infectious process that develops in utero and is triggered by a second event that occurs postnatally.
Kwan: Breast milk contains a lot of immunological factors that are passed passively from the mom to the child and can boost the child's immune system. So his or her immune system might be able to avoid these common childhood infections that's the necessary second event leading to the presentation of childhood leukemia.
Narrator: For Science Today, I'm Larissa Branin.
B.
Progress in Diagnosing Alzheimer's Disease
Narrator: This is Science Today. As we get older, we all experience changes in memory – and while most of it is simply age-related, sometimes these changes lead to Alzheimer's disease.
Jagust: As much as technology has improved, still the only way we can diagnose Alzheimer's disease with certainty is with an autopsy. But one of the things that's happened in the last 10 to 15 years is the National Institute on Aging has funded a lot of Alzheimer's research centers around the country and one of the things that these centers have been doing is following patients over time, making a diagnosis and then following over time and getting an autopsy – and so we know how well we do now when we make a diagnosis of Alzheimer's disease. And the fact is, we do pretty well.
Narrator: Dr. William Jagust, a professor of public health and neuroscience at the University of California, Berkeley, will be adding to this knowledge as part of a large five-year initiative looking into how well PET scans can predict the onset of Alzheimer's disease. For Science Today, I'm Larissa Branin.
C.
The Cause of Animal Extinctions During the Pleistocene
Narrator: This is Science Today. The extinction of Earth's large mammals during the late Pleistocene – about 50 thousand and 10 thousand years ago – could happen again within the next one hundred years. Tony Barnosky, a professor of integrative biology at the University of California, Berkeley, says just as in the Pleistocene, the cause of this extinction may be a combination of climate change and increased human population sizes.
Barnosky: The reason that's relevant now is because we're entering into a phase where we have got the same two things acting in a much more scaled up way.
Narrator: For years there has been a very polarized debate between those who favor humans as the main cause of the extinctions versus those who blame climate change. In a recent review, Barnosky concluded it was both.
Barnosky: I think what's significant about this study is it shows that really in some places, we can pretty clearly document that it was climate change. In other places, we can pretty clearly document that climate probably wasn't so important – that it was human population pressure.
Narrator: For Science Today, I'm Larissa Branin.
D.
Screening Methods for Colon Cancer
Narrator: This is Science Today. While there's been some debate over which colon cancer screening method is best, one thing is clear – the importance of getting one if you are 50 and older or at higher risk. Dr. Uri Ladabaum of the University of California, San Francisco says that's because colon cancer, which is the second leading cause of cancer death in this country, is very preventable.
Ladabaum: We have many screening options available. Colonoscopy may not be for everybody, but it's clear that some form of screening is better than no screening. So I would urge everybody to consider some form of screening, whether it's fecal occult blood testing, sigmoidoscopy or colonoscopy. And then, when virtual colonoscopy and other emerging methods are available, those can be considered as well. But it is more important to get screened with whatever modality one chooses than to be essentially paralyzed by the dilemma of which screening test one should use.
Narrator: One advantage for patients is that if screening is normal and no symptoms develop, they don't need to be tested again for another ten years. For Science Today, I'm Larissa Branin.
E.
The Impact of Arm Position on Blood Pressure Readings
Narrator: This is Science Today. Studies dating back to the early 1900s had noticed the impact of arm position on blood pressure readings, but despite the fact this observation had been made, most studies do not stipulate position of the arm in their methodologies. Dr. David Guss, Director of Emergency Medicine at the University of California, San Diego, recently found arm position does matter when taking blood pressure readings.
Guss: We analyzed our data and lo and behold, we found that there was a very significant difference between the blood pressure measured with the arm at the side as compared with the arm perpendicular – generally 10 to 15 percent difference in the actual mean value.
Narrator: Guss says this is important to note – especially in the emergency department setting, where a patient's blood pressure is repeatedly measured.
Guss: We should pay careful attention to making sure that the arm is in the same position from measurement to measurement, so that any changes that we are encountering are due to a change in the patient's physiology, rather than in the position of the arm.
Narrator: For Science Today, I'm Larissa Branin.
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