26/03/2019

New urine test predicts high-grade cancer

Double dippers are everywhere – the 4th of July barbeque, family reunions, Super Bowl parties, anywhere chips and dip are a staple. These are the people who take a bite and dip their chips a second time when they think no one is looking.
Just ask George

Leave it to George Costanza on Seinfeld to make double dipping a mainstream public health scare. The episode, which originally aired in 1993, brought shame to George as he was caught dipping a chip a second time at a wake. The partygoer objecting to this practice exclaims “That’s like putting your whole mouth right in the dip!”
But is double dipping really so bad?

Ever since that Seinfeld episode, the “health menace” of double dipping has been a mainstay of party conversation, high school science projects, and even high-level academic investigation. Perhaps the most influential was a 2009 study performed at Clemson University and published in the Journal of Food Safety, entitled “Effect of biting before dipping (double-dipping) chips on the bacterial population of the dipping solution.” The title alone may be enough to make you lose your appetite.

The researchers carefully analyzed bacterial contamination before and after a person double dips. Here’s what they found:

    Bacterial counts in the dip increased significantly after a person took a bite from a chip and then dipped again.
    The number of bacteria contaminating the dip varied depending on the dip – salsa had more bacteria after double-dipping compared with chocolate or cheese dips (perhaps due to differences in thickness and acidity of the dips).

Similar findings were noted when bacteria counts were measured after a bitten chip was dipped in water.
So just how risky is double dipping?

It’s important to note that this research was not designed to find people who became sick because someone else double dipped. And, considering that our mouths are normally packed with bacteria, it doesn’t necessarily follow that more bacteria in the dip means double dipping is dangerous.

However, this research does raise the possibility that a person who is sick (or about to be) might spread a disease by re-dipping a chip. Documented examples of this are hard to find – if you know of one, let me know! But even if the risk is hard to prove, the risk may be real. We know of many respiratory diseases that can be spread by contact with saliva, such as influenza (the flu) or whooping cough. Still, there are probably much bigger risks at your next office party than double dipping. You’re more likely to contract an illness from a sick person coughing or sneezing in your face or if they don’t wash their hands while sick than you are from a healthy double-dipper. So, while it’s reasonable to discourage double dipping, it’s unlikely to pose a major risk to your health.
And if you’re a double dipper…

And, for habitual double-dippers, I wonder about a more responsible option: turn the chip around to double dip from the unbitten end of the chip. Stand by – somewhere in America there is a high school kid setting up that experiment right now. As the 2016 summer Olympics get underway, we will see elite women athletes compete at the highest level of their sports. And as we cruise toward September, many more young women will return to the field, court, and pool on college and high school teams. We know that many women who don’t consider themselves athletes exercise more and restrict calories to lose or maintain their weight. This can be a formula for disaster.

The benefits of an active lifestyle and participation in sports are many. However, proper and adequate nutrition is paramount to a woman’s health — particularly for strong and healthy bones. This is especially true for female athletes.

After Title IX — which ensured athletic opportunities for women in programs that received federal financial assistance — was passed in 1972, the number of women participating in sports skyrocketed. About 20 years after Title IX, a group of physicians identified a set of three symptoms commonly seen in women athletes. The original definition of the female athlete triad consisted of eating disorders, irregular menstrual cycles, and reduced bone mineral density (weakened bone strength that can lead to osteoporosis). Malnutrition led to abnormalities in the menstrual cycle, which in turn affected bone density.

The triad was thought to affect primarily women participating in weight-dependent or judging sports, such as gymnastics, ice skating, or endurance running. However, many athletes remained undiagnosed because criteria for the triad diagnosis remained elusive. In 2007, the definition transitioned into a spectrum disorder involving “low energy availability” (inadequate carbohydrate intake), absence of menstrual periods, and decreased bone mineral density.

Most recently the International Olympic Committee has coined the term RED-S — Relative Energy Deficiency in Sport. This exemplifies the importance of fueling your body with the appropriate amount of energy (food) for the duration and intensity of activity performed. In other words, if you don’t eat enough, there will be repercussions, some serious. Poor nutrition and insufficient calories for the amount of exercise you do will lead to changes in your body’s hormone levels and directly affect bone density.
Why is it so important to balance activity and adequate nutrition?

Let’s talk about bone health. We know that we can build bone density until about age 25. After that we can only work to maintain what we’ve got. If young female athletes are losing bone density, it can never be replaced.

We also know that female athletes suffer from two to three times the number of stress fractures compared to male athletes. And women athletes with missed menstrual cycles (which can happen when activity outpaces calories consumed) have two to four times the risk of stress fractures compared to women with normal monthly menstrual cycles.

A stress fracture occurs when the bone is subject to more stress or impact than it can handle. This may simply be due to overtraining, or increasing training too quickly without giving the bones adequate time to adapt. Stress fractures can also be due to a lower bone mineral density, which means it takes less force to cause damage. This often is the result of the female athlete triad — a direct result of not eating enough, or not eating enough of the right foods. If we can educate our youth on the importance of maintaining a healthy diet and supplying their active bodies with the energy they need, then we can prevent many of these injuries and maybe even reduce the chances that a woman develops osteoporosis later in life.

We know exercise is important. We know that a healthy weight is important. But what may not get enough attention is the fact that eating healthy calories to replenish and fuel the body is vital to athletes’ health, in particular for strong and resilient bones. Remember, bones are also a girl’s best friends. And they should be like diamonds — strong and dense. We need to work to make sure they are. Suspicious findings from prostate cancer screening are often followed by a procedure most men would prefer to avoid: a prostate biopsy. But what if biopsies actually could be avoided on the basis of non-invasive test results? Screening tests are moving in that direction, with some intriguing results. One of them, the Prostate Health Index blood test, combines measures of three forms of prostate-specific antigen (PSA) into a score that helps doctors predict if a cancer is likely to progress, with an aim to circumvent biopsies that aren’t necessary. Another non-invasive test, called the PCA3 assay, measures genetic evidence of aggressive cancer in urine samples, and generates a score designed to help doctors assess the need for a repeat biopsy. Though approved by the Food and Drug Administration, these tests aren’t perfect, and experts question the reliability of the PCA3 test in particular.

Now researchers are considering the value of a new test that also looks for evidence of high-grade prostate cancer in urine. The results were reported in the Journal of the American Medical Association last April. Called the “urine exosome gene expression assay,” it measures not just PCA3 but also two other genes associated with high-grade disease: ERG and SPDEF. The test combines those measures into a diagnostic score that “could help determine if an initial prostate biopsy is warranted,” said its co-developer Dr. Michael Donovan, a pathologist and researcher at The Mount Sinai Hospital in New York. According to Donovan, the goal is to limit the number of prostate cancer biopsies, which are costly, painful, and prone to hospital-acquired infections.

The study enrolled 1,563 men from 22 community and academic urology clinics in the United States. According to results with a final grouping of 519 men, assay scores over a “cut-off” value of 15.6 predicted high-grade cancer correctly 92% of the time. The assay didn’t always get it right: 12 men were misdiagnosed as having low-risk cancer when they in fact had higher-grade disease.. But most of those tumors, Donovan said, fell into an intermediate-risk category that some doctors would consider eligible for active surveillance instead of treatment.

The genes measured reside in small vesicles called exosomes that are secreted by prostate cells. For the test, men have to provide a “first-catch” urine sample. That’s because prostate exosomes are concentrated in the initial stream and numbers decline as urination continues. “In our view, the assay can be combined with other standard-of-care factors during clinical decision making,” Donovan said. “Right now, it’s designed for men who have never had a biopsy, but we’re also moving towards studies that will assess its use in other settings, such as active surveillance.”

Dr. Marc Garnick, the Gorman Brothers Professor of Medicine at Harvard Medical School and Beth Israel Deaconess Medical Center, and editor in chief of HarvardProstateKnowledge.org, cautioned that while the number of non-invasive tests for prostate cancer diagnosis is growing, these are still early days in their development. “Until we better understand how these tests correlate with the behavior of the prostate tumors they can help diagnose, they remain very much in the research sphere,” he said.

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