The uproar that began last year when the U.S. Preventive Services Task Force stated that doctors should no longer offer regular prostate-cancer tests to healthy men continued this week when the task force released their final report. Overall, they stuck to their guns, stating that a blood test commonly used to screen for prostate cancer, the PSA test, causes more harm than good — it leads men to receive unnecessary, and sometimes even dangerous, treatments.
But many people simply don’t believe that the test is ineffective. Even faced with overwhelming evidence, such as a ten-year study of around 250,000 men that showed the test didn’t save lives, many activists and medical professionals are clamouring for men to continue receiving their annual PSA test. Why the disconnect?
In an article, researchers Hal R. Arkes, of Ohio State University, and Wolfgang Gaismaier, from the Max Planck Institute for Human Development in Berlin, Germany, picked apart lay-people’s reactions to the report, and examined the reasons why people are so reluctant to give up the PSA test.
‘Many folks who had a PSA test and think that it saved their life are infuriated that the Task Force seems to be so negative about the test,’ said Arkes.
They suggest several factors that may have contributed to the public’s condemnation of the report. Many studies have shown that anecdotes have power over a person’s perceptions of medical treatments. For example, a person can be shown statistics that Treatment A works less frequently than Treatment B, but if they read anecdotes (such as comments on a website) by other patients who had success with Treatment B, they’ll be more likely to pick Treatment B. The source of the anecdotes matters too. If a friend, a close relative, or any trusted source received successful treatment, they would be more likely to recommend that treatment to others, even if there was evidence showing the treatment only works for a minority of people.
Arkes and Gaismaier also propose that the public may have recoiled against the task force’s recommendations so fiercely because they weren’t able to properly evaluate the data in the report. Confusion over the use of control groups may have led people in the general public to weigh the data differently than medical professionals did.
‘How to change this is the million-dollar question,’ said Arkes. ‘Pictorial displays are far easier to comprehend than statistics. The two figures in our article depict the situation more clearly than text and numbers can do. I think data displayed in this manner can help change people’s view of the PSA test because we compare the relative outcomes of being tested and not being tested. Without that comparison, it is tough for the public to appreciate the relative pluses and minuses of the PSA test versus not having the PSA test.’
Men will be able to continue to request the PSA test, and it will be covered by health insurance for the foreseeable future. But psychological science suggests that unless people are convinced to choose statistics over anecdotes, confusion surrounding the test’s effectiveness will linger. Association for Psychological Science

The Caterpillar got down off the mushroom … remarking as it went, ‘One side will make you grow taller, and the other side will make you grow shorter.’

—Lewis Carroll, ‘Alice’s Adventures in Wonderland’

UCLA geneticists have identified the mutation responsible for IMAGe syndrome, a rare disorder that stunts infants’ growth. The twist? The mutation occurs on the same gene that causes Beckwith–Wiedemann syndrome, which makes cells grow too fast, leading to very large children.

The UCLA findings could lead to new ways of blocking the rapid cell division that allows tumours to grow unchecked. The discovery also offers a new tool for diagnosing children with IMAGe syndrome, which until now has been difficult to identify accurately.

The discovery holds special significance for principal investigator Dr. Eric Vilain, a professor of human genetics, paediatrics and urology at the David Geffen School of Medicine at UCLA.

Nearly 20 years ago, as a medical resident in his native France, Vilain cared for two boys, ages 3 and 6, who were dramatically short for their ages. Though unrelated, the children shared a mysterious malady marked by minimal foetal development, stunted bone growth, sluggish adrenal glands, and undersized organs and genitals.

‘I never found a reason to explain these patients’ unusual set of symptoms,’ said Vilain, who also directs the UCLA Institute for Society and Genetics. ‘I’ve been searching for the cause of their disease since 1993.’

When Vilain joined UCLA as a genetics fellow, the two cases continued to intrigue him. His UCLA mentor at the time, geneticist Dr. Edward McCabe, recalled a similar case from his previous post at Baylor College of Medicine. The two of them obtained blood samples from the three cases and analysed the patients’ DNA for mutations in suspect genes but uncovered nothing.

Vilain and McCabe approached the Journal of Clinical Endocrinology and Metabolism and in 1999 published the first description of the syndrome, which they dubbed IMAGe, an acronym of sorts for the condition’s symptoms: intrauterine growth restriction, metaphyseal dysplasia, adrenal hypoplasia and genital anomalies.

Over the next decade, about 20 cases were reported around the world. But the cause of IMAGe syndrome remained a mystery.

Help arrived unexpectedly last year, when Vilain received an email from Argentinian physician Dr. Ignacio Bergada, who had unearthed the 1999 journal article. He told Vilain about a large family he was treating in which eight members suffered the same symptoms described in the study. All of the family members agreed to send their DNA samples to UCLA for study.

Vilain realized that he had stumbled across the scientific equivalent of winning the lottery. He assembled a team of UCLA researchers to partner with Bergada and London endocrinologist Dr. John Achermann.

‘At last, we had enough samples to help us zero in on the gene responsible for the syndrome,’ Vilain said. ‘Sequencing technology had also advanced in sophistication over the past two decades, allowing us to quickly analyse the entire family’s DNA samples.’

Vilain’s team performed a linkage study, which identifies disease-related genetic markers passed down from one generation to another. The results steered Vilain to a huge swath of Chromosome 11.

The UCLA Clinical Genomics Center performed next-generation sequencing, a powerful new technique that enabled the scientists to scour the enormous area in just two weeks and tease out a slender stretch that held the culprit mutation. The team also uncovered the same mutation in the original three cases described by Vilain and McCabe in 1999.

‘We discovered a mutation in a tiny sliver of the chromosome that appeared in every family member affected by IMAGe syndrome,’ Vilain said. ‘This was a big step forward. Now we can use gene sequencing as a tool to screen for the disease and diagnose children early enough for them to benefit from medical intervention.

‘We were a little surprised, because the mutation was located on a famous gene recognised for causing Beckwith–Wiedemann syndrome,’ he added. ‘The two diseases are polar opposites of each other.’

Children born with Beckwith–Wiedemann syndrome — named for the two doctors who discovered it — grow very large, with big adrenal glands, elongated bones and oversized internal organs. Because their cells grow so fast, one in five children with the disorder die of cancer at a young age. The disease appears in approximately one out of 15,000 births.

‘Finding opposite functions in the same gene is a rare biological phenomenon,’ Vilain emphasised. ‘When the mutation appeared in the slim section we identified, the infant developed IMAGe syndrome. If the mutation fell anywhere else in the gene, the child was born with Beckwith–Wiedemann. That’s really quite remarkable.’ UCLA

For 5,000 years, the Chinese have used a system of medicine based on the flow and balance of positive and negative energies in the body. In this system, the appearance of the tongue is one of the measures used to classify the overall physical status of the body, or zheng. Now, University of Missouri researchers have developed computer software that combines the ancient practices and modern medicine by providing an automated system for analysing images of the tongue.
‘Knowing your zheng classification can serve as a pre-screening tool and help with preventive medicine,’ said Dong Xu, chair of MU’s computer science department in the College of Engineering and study co-author. ‘Our software helps bridge Eastern and Western medicine, since an imbalance in zheng could serve as a warning to go see a doctor. Within a year, our ultimate goal is to create an application for smartphones that will allow anyone to take a photo of their tongue and learn the status of their zheng.’
The software analyses images based on the tongue’s colour and coating to distinguish between tongues showing signs of ‘hot’ or ‘cold’ zheng. Shades of red and yellow are associated with hot zheng, whereas a white coating on the tongue is a sign of cold zheng.
‘Hot and cold zheng doesn’t refer directly to body temperature,’ said Xu, who is also on the faculty of the Bond Life Sciences Center. ‘Rather, it refers to a suite of symptoms associated with the state of the body as a whole.’
For example, a person with cold zheng may feel chills and coolness in the limbs and show a pale flushing of face. Their voice may have a high pitch. Other symptoms of cold sheng are clear urine and loose stool. They also may prefer hot foods and drinks and desire warm environments.
In Chinese traditional medicine both hot and cold zheng can be symptoms of gastritis, an inflammation of the stomach lining frequently caused by bacterial infection.
For the study, 263 gastritis patients and 48 healthy volunteers had their tongues analysed. The gastritis patients were classified by whether they showed infection by a certain bacteria, known as Helicobacter pylori, as well as the intensity of their gastritis symptoms. In addition, most of the gastritis patients had been previously classified with either hot or cold zheng. This allowed the researchers to verify the accuracy of the software’s analysis.
‘Our software was able to classify people based on their zheng status,’ said study co-author Ye Duan, associate professor of computer science at MU.
‘As we continue to work on the software we hope to improve its ability,’ Duan said. ‘Eventually everyone will be able to use this tool at home using webcams or smartphone applications. That will allow them to monitor their zheng and get an early warning about possible ailments.’ University of Missouri

Biomedical engineers at UC Davis have developed a microfluidic chip to test for latent tuberculosis. They hope the test will be cheaper, faster and more reliable than current testing for the disease.
‘Our assay is cheaper, reusable, and gives results in real time,’ said Ying Liu, a research specialist working with Professor Alexander Revzin in the UC Davis Department of Biomedical Engineering.
The team has already conducted testing of blood samples from patients in China and the United States.
About one-third of the world’s population is infected with the bacteria that cause tuberculosis, a disease that kills an estimated 1.5 million people worldwide every year, according to the U.S. Centers for Disease Control and Prevention.
Most infected people have latent TB, in which the bacteria are kept in check by the immune system. Patients become sick only when the immune system is compromised, enabling the bacteria to become active. People with HIV are at especially high risk.
Current tests for latent TB are based on detecting interferon-gamma, a disease-fighting chemical made by cells of the immune system. Commercially available tests require sending samples to a lab, and can be used just once.
Liu and Revzin used a novel approach: They coated a gold wafer with short pieces of a single-stranded DNA segment known to stick specifically to interferon-gamma. They then mounted the wafer in a chip that has tiny channels for blood samples. If interferon-gamma is present in a blood sample, it sticks to the DNA, triggering an electrical signal that can be read by a clinician.
‘If you see that the interferon-gamma level is high, you can diagnose latent TB,’ Liu said.
The researchers plan to refine the system so that the microfluidic sensor and electronic readout are integrated on a single chip. UC Davis