Tracing DNA changes and hair color
Published 4:49 pm, Tuesday, June 3, 2014
Tale of Goldilocks and the DNA
Blond or brunette? Your hair color was determined by tiny changes in your DNA that affected solely the pigment of your tresses and no other trait, according to a new Stanford study.
The study, considered the first to determine the molecular basis for hair color, outlined how these subtle DNA changes affect one of our most noticeable characteristics.
Stanford researchers found that blond hair, the kind commonly seen in Northern Europeans, is caused by a single change in the DNA that regulates the expression of a gene that affects a protein called KITLG. That small change determines how much KITLG is expressed in the hair follicles.
They tested the concept by introducing the change into normally brown-haired mice. Mice with the DNA change turned out to have a much lighter coat. While they may have been blond, it's unclear whether they had more fun.
The study was published Sunday in the journal Nature Genetics.
HER2 can be signal for low rate of recurrence
Breast cancer patients with small tumors that express large amounts of a protein molecule called HER2 had a low risk of recurrence even without being treated with chemotherapy or a targeted therapy, according to a new Kaiser study.
Kaiser researchers reviewed the records of 16,975 breast cancer cases diagnosed between 2000 and 2006, about 14 percent, or 2,168, of whom were HER2-positive. None of them was treated with chemotherapy or the antibody sold under the brand name Herceptin, which targets the HER2 molecule.
They found that 234 HER2-positive patients had the smallest tumors - half a centimeter or smaller - and 99 percent of them were alive five years later and had no distant recurrence - cancer that recurs outside the breast or another organ.
Among the 116 patients with tumors between .6 and 1 centimeter, 97 percent had survived five years without a distant recurrence.
The researcher said the results suggest that women with small HER2-positive tumors may not need the targeted therapy, suggesting the more aggressive treatments be reserved for patients with larger tumors.
Patients generally respond well to Herceptin, but it can lead to heart failure in some women, particularly those who are older and have other diseases, researchers said.
The study was published Monday in the Journal of Clinical Oncology.
- Victoria Colliver
Link between pain sensation and aging
Blocking a protein receptor that senses pain - in particular, the "hot" sensation associated with chili peppers - appears to help mice live longer and improves their metabolism, according to research from UC Berkeley.
Commonly known as the "capsaicin receptor" because of its strong association with the chili pepper compound, the TRPV1 receptor is found on cells in the skin, nerves and joints. But it's also found in cells near the pancreas, where it can prevent insulin release.
The scientists found that by blocking the receptor, they didn't just improve pain in mice. Animals that were genetically engineered to not have the receptor lived about four months longer than other mice.
They also had metabolisms similar to those typically found in younger mice. The engineered mice had lower levels of a molecule that blocks insulin release and they were better at clearing sugar from their blood.
The findings suggest there may be a close relationship between pain sensation and aging, the scientists said. And they point to avenues for new research into diseases like Type 2 diabetes.
The findings were published May 22 in the journal Cell.
- Erin Allday
Process helps avoid immune reaction
Transplanting manufactured stem cells that have been coaxed toward their final state - such as a particular kind of heart cell - appears to be less likely to induce an immune reaction than transplanting cells that haven't yet become specialized, according to Stanford scientists.
Researchers have long believed that induced pluripotent stem (IPS) cells - a type of cell that is created when scientists manipulate an "adult" cell and regress it to an embryonic-like state that allows it to become any other kind of cell - should be safe for transplantation when they're created from the subject's own tissue.
But studies have found that's not the case, and the body often rejects transplanted IPS cells.
The Stanford team, studying mice, found that when IPS cells were further manipulated beyond their embryonic-like state and turned into specialty cells, the immune system didn't attack them after they were transplanted.
The scientists speculate that when adult cells are regressed to an early stage of life, they release some kind of molecule that makes them look unfamiliar - and necessary of attack - to the immune system. But further manipulating the cells into a more specialized state seems to avoid that immune reaction.
Their results were published online May 30 in the journal Nature Communications.
A Kaiser Permanente study connects trust between diabetics and their health care providers with patients sticking to depression treatment, in turn helping to control diabetes.
When adult diabetics didn't feel included in decision-making about their treatment, they were more than two times likelier not to fill antidepressant prescriptions, the study found. They were also less likely to refill their prescriptions and stay on antidepressants later.
The research suggests that communication and joint decision-making were especially important in early phases of a diabetic patient's depression treatment.
About 11 percent of men and 10 percent of women over age 20 have diabetes, according to the National Institute of Diabetes and Digestive and Kidney Diseases.
The study was published in the Journal of General Internal Medicine in April.
OBESITY AND DIABETES
Restriction on aid can pay health dividends
Stanford scientists believe prohibiting the purchase of sugary drinks with SNAP funds (formerly the food stamps program) could cut obesity and type-2 diabetes rates in low-income populations.
Computer simulations found that an all-out ban on SNAP-funded sugary drinks reduced type-2 diabetes in adults by 2.3 percent and reduced new obesity cases in 281,000 adults and half as many children.
Experimenting with healthy eating incentives, Stanford simulations also found that giving participants an extra 30 cents for every dollar spent on fruit and veggies would add an average quarter cup of healthy foods to SNAP enrollees' plates daily. The incentive alone didn't change the obesity rate or the number of adults with Type 2 diabetes.
Last year, 18 U.S. mayors, including San Francisco Mayor Ed Lee and Oakland Mayor Jean Quan, sent a letter urging Congress to limit SNAP's subsidy of sugary drinks and promote fruits and vegetables. Their requests didn't make it into the farm bill.
More than 47 million Americans were enrolled in SNAP in 2013. Beneficiaries are currently allowed to use SNAP funds to buy food and seeds that produce food, but they aren't permitted to buy alcohol, cigarettes, food eaten in-store or hygiene products.
The Stanford study was published in the June issue of Health Affairs, a health policy journal.