Month: October 2015

Stanford expert calls for more targeted anti-obesity policies

U. S. Department of Agriculture's helps educate shoppers about the value of food labeling in December 1975. Photo courtesy National Archives and Records Administration.
U. S. Department of Agriculture helps educate shoppers about the value of food labeling in 1975. Photo courtesy National Archives and Records Administration.

Reality TV shows like “The Biggest Loser” are popular in part because the audience can relate to the participants — more than two-thirds of adults and about one-third of children and adolescents are obese or overweight in the US. The Surgeon General and the Centers for Disease Control and Prevent have declared obesity to be a national epidemic and a major contributor to leading causes of death, including heart disease, stroke, diabetes and some types of cancer.

Although our country is committed to finding solutions to the increase in obesity, public policies have fallen short, according to Deborah Rhode, JD, a Stanford law professor and legal ethics scholar. In a recent journal article, she wrote:

Many policy responses have proven controversial, and those most often recommended have frequently faced an uphill battle at the federal, state, and local level. At the same time that obesity rates have been rising sharply, many jurisdictions have resisted, or rolled back, strategies such as soda taxes or regulation of advertising directed at children.

In the journal article, Rhode evaluates anti-obesity policies, including calorie disclosure requirements, taxes or bans on sugar-sweetened beverages, food stamp modifications, zoning regulations, children’s marketing restrictions, physical activities initiatives, food policies and education. She suggests that a more targeted approach is needed to combat obesity. For instance, Rhode recommends creative zoning regulations that restrict the location of fast-food restaurants near schools while encouraging healthy food retailers in underserved neighborhoods.

In a Stanford news release, Rhode noted that the first lady Michelle Obama’s “Let’s Move!” campaign against childhood obesity applies to politics as well as physical activity. Rhode summarized, “Although we need more evaluation of policy strategies, we know enough about what works to chart a course of reform. We should act now on what we know.”

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Tattoo ink may mimic cancer on PET-CT images

19824000898_7611622d67_o_Flickr_PauloGuereta
Photograph by Paulo Guereta

The hit new crime thriller Blindspot is about a mysterious woman, Jane Doe, who is covered in extensive full-body tattoos. If Jane Doe were a real woman who ever needed medical imaging, she might need to be concerned.

In a case report published recently in the journal Obstetrics & Gynecology, researchers found that extensive tattoos can mimic metastases on images from positron emission tomography (PET) fused with computed tomography (CT). PET-CT imaging is commonly used to detect cancer, determine whether the cancer has spread and guide treatment decisions. A false-positive finding can result in unnecessary or incorrect treatment.

Ramez N. Eskander, MD, assistant professor of obstetrics and gynecology at UC Irvine, and his colleagues describe the case study of a 32-year-old woman with cervical cancer and extensive tattoos. The pre-operative PET-CT scan using fluorine-18-deoxyglucose confirmed that there was a large cervical cancer mass, but the scan also identified two ileac lymph nodes as suspicious for metastatic disease. However, final pathology showed extensive deposition of tattoo ink and no malignant cells in those ileac lymph nodes.

It is believed that carbon particles in the tattoo pigment migrate to the nearby lymph nodes through macrophages, using mechanisms similar to those seen in malignant melanoma. The researchers explain in their case report:

Our literature search yielded case reports describing the migration of tattoo ink to regional lymph nodes in patients with breast cancer, melanoma, testicular seminoma, and vulvar squamous cell carcinoma, making it difficult to differentiate grossly between the pigment and the metastatic disease, resulting in unnecessary treatment.

The authors warn other physicians to be aware of the possible effects of tattoo ink on PET-CT findings when formulating treatment plans, particularly for patients with extensive tattoos.

This is a reposting of my Scope blog story, courtesy of Stanford School of Medicine.

Is it time to compensate kidney donors?

Kidney transplant surgery (Tareq Salahuddin)
Kidney transplant surgery (Tareq Salahuddin)

A recent New York Times blog entry editorialized on the worldwide shortage of transplant kidneys, raising the question of whether it’s time to compensate kidney donors to meet the growing need. The blog echoed the debate that is emerging in the United States among some doctors, medical societies, and groups that oversee organ transplants.

Taboos against paying for transplant organs are powerful. But these may be overcome by necessity, since the demand for transplant kidneys is growing at an alarming rate largely due to kidney failure from diabetes, high blood pressure and obesity-related diseases. According to the National Kidney Foundation, 450,000 Americans are on dialysis and the severe shortage of transplant kidneys in the U.S. results in 12 patient deaths each day.

Laying the groundwork for change, a collaboration of nephrology and finance experts, including Philip J. Held, PhD, a Stanford consulting professor of nephrology, performed a comprehensive cost-benefit analysis of a proposed government program for kidney donor compensation. In a study published last week in the American Journal of Transplantation, the authors estimate the shortage of transplant kidneys would be eliminated within five years if the government compensates living kidney donors $45,000 and the estates of deceased donors $10,000. The proposed compensation would also include an insurance policy against any health problems that might result from the donation.

The authors’ analysis shows that the benefits of a donor compensation program would greatly exceed the costs for society in general and taxpayers in particular. The researchers calculate the monetary value of a longer and healthier life for each kidney recipient at $1.3 million, with the added bonus of saving $1.5 million for not needing expensive dialysis treatments. After subtracting from these benefits the cost of transplants, society would enjoy a net welfare gain of $1.9 million over the lifetime of each kidney recipient. Since taxpayers currently pay about 75 percent of the cost of both dialysis and kidney transplants, this represents a taxpayer savings of about $400,000 per kidney recipient.

One of the main arguments against kidney donor compensation is that rich people would buy kidneys from poor people, exploiting them and causing them harm. The authors argue that the opposite is true because the poor, especially poor African Americans, are overrepresented on the kidney waiting list – so they would enjoy the greatest benefit.

The researchers summarized their findings in a press release supplied to our office:

“In sum, having the government compensate kidney donors would be a win-win-win situation. Kidney recipients would enjoy much longer and healthier lives. Kidney donors would receive compensation for their gift of life, whereas now they receive nothing. And taxpayers would save money because transplantation is not only a more effective treatment for kidney failure than dialysis, it is a much less expensive one.”

This is a repost of my Scope blog story, courtesy of Stanford School of Medicine.

Stanford engineers create artificial skin that can signal pressure sensation to brain

The device on the golden fingertip is the skin-like sensor developed by Stanford engineers. (Bao Lab)
The device on the golden fingertip is the skin-like sensor developed by Stanford engineers. (Bao Lab)

A hand without a sense of touch doesn’t really feel like a hand, many amputees describe. It’s more like a pliers that can be manipulated by sending signals from the brain to the prosthetic device. They dream of being able to delicately pick up a glass or to feel the touch of a loved one’s hand.

Stanford chemical engineering professor Zhenan Bao, PhD, and her team have spent a decade trying to help make this dream a reality, by developing a material that mimics skin and its sensory functions. Taking a big step towards this goal, they have now created a skin-like material that can tell the difference between a soft touch and a firm handshake.

Their artificial skin has two layers. The bottom layer acts as a circuit that transports pulses of electricity to nerve cells and translates these signals into biochemical stimuli that the nerve cells can detect. The top layer is a sensing mechanism composed of thin plastic embedded with billions of carbon nanotubes. When pressure is put on the plastic, the nanotubes are squeezed closer together enabling them to conduct electricity. What’s new is that the top layer can now detect pressure over the same range as human skin.

According to a Stanford news release:

This allowed the plastic sensor to mimic human skin, which transmits pressure information to the brain as short pulses of electricity, similar to Morse code. Increasing pressure on the waffled nanotubes squeezes them even closer together, allowing more electricity to flow through the sensor, and those varied impulses are sent as short pulses to the sensing mechanism. Remove pressure, and the flow of pulses relaxes, indicating light touch. Remove all pressure and the pulses cease entirely.

A paper describing Bao’s new research has just been published in Science. As Bao comments in the release, “We have a lot of work to take this from experimental to practical applications. But after spending many years in this work, I now see a clear path where we can take our artificial skin.”

This is a repost of my Scope blog story, courtesy of Stanford School of Medicine.