Posts Tagged ‘information’

Some women still don’t underststand ‘overdiagnosis’ risk in breast screening

In a survey of around 2,200 women, Cancer Research UK scientists at University College London (UCL) found that 64 per cent felt they fully understood the information given about overdiagnosis — the chance that screening will pick up cancers that would never have gone on to cause any harm — by the National breast screening programme.

Information about overdiagnosis has only been included in the NHS breast screening invitation leaflets since late 2013, meaning that overdiagnosis is likely to be a new concept for many people.

But despite uncertainty over the information they were given, intentions to attend breast screening remained high, with only seven per cent of women saying they would be less likely to attend screening after receiving the overdiagnosis information. On the other hand, four per cent of women said they would be more likely to attend screening after receiving the information.

Study author, Dr Jo Waller, a researcher at the Health Behaviour Research Centre at UCL, said: “While there is clearly room for improvement, the information leaflet does appear to help some women make a decision about whether or not to have breast screening.

“But the study found that many women still struggle to understand the balance of benefits and harms linked to breast screening, so we need to find better ways to communicate the risks as well as the benefits.”

Overdiagnosis happens because some breast cancers grow so slowly that it would take more than a lifetime for them to threaten a woman’s health. For every life that is saved through screening, researchers estimate that around three women will be overdiagnosed with breast cancer, although there is presently no way of telling the difference between life-threatening cancers and cancers that are overdiagnosed, either at diagnosis or after treatment.

Sara Hiom, Cancer Research UK’s director of early diagnosis, said: “We think it’s vitally important for women to have clear information about breast screening, the balance of benefits and harms and the fact that they could be diagnosed with and treated for a cancer that might not have caused them harm.

“We are committed to providing quality information that can help women understand the harms and benefits of breast screening, and research like this can help us refine the information we offer to be sure that it is as helpful and understandable as possible.

“The concept of overdiagnosis is still very new for a lot of women because it has only been included in the NHS leaflets for a year. We hope that over time, people’s understanding of this concept will increase as more and more women receive information explaining this risk of screening.

“Any woman invited for breast screening and worried about the risks of overdiagnosis can speak to our specialist cancer nurses on freephone 0808 800 4040.”

source : http://www.sciencedaily.com/releases/2014/08/140829083906.htm

No apparent link between sleep apnea and cancer: Large study

Studies have postulated that obstructive sleep apnea may be linked to cancer because of low levels of oxygen in the blood.

“There is a need for a sufficiently large cohort study with a long enough follow-up to allow for the potential development of cancer that adjusts for important potential confounders, examines common cancer subtypes and has a rigorous assessment of both obstructive sleep apnea and cancer,” writes Dr. Tetyana Kendzerska, Institute for Clinical Evaluative Sciences (ICES) and Women’s College Hospital, University of Toronto, Toronto, Ont., with coauthors.

To understand whether obstructive sleep apnea is associated with cancer development, researchers undertook a study of 10 149 patients with the disorder who underwent a sleep study between 1994 and 2010. They linked this information to health administrative databases from 1991 to 2013. At the start of the study, 520 (5.1%) had a cancer diagnosis. In the study follow-up period (median 7.8 years), 627 (6.5%) people who did not have cancer at baseline had incident cancer. Prostate, breast, colorectal and lung cancers were the most common.

After controlling for cancer risk factors, the researchers found no apparent causal link between obstructive sleep apnea and cancer.

“We were not able to confirm previous hypotheses that obstructive sleep apnea is a cause of overall cancer development through intermittent hypoxemia [low blood oxygen levels],” write the authors. “However, in subgroup analyses, we found that the level of oxygen desaturation was associated with the development of smoking-related cancer.”

source : http://www.sciencedaily.com/releases/2014/08/140805132001.htm

Trapped: Cell-invading piece of virus captured in lab by scientists

This achievement sets the stage to use x-ray crystallography to develop complete images of HIV that include integrase, which in turn will help scientists develop new treatments for the illness.

Duane Grandgenett, Ph.D., professor at SLU’s Institute of Molecular Virology and senior author of the study, discovered integrase in 1978, little knowing the piece of virus would provide the basis for an entire class of drugs that now treats HIV.

“In 1974, we hadn’t heard of HIV yet,” Grandgenett said. “We did, however, study retroviruses, the class of viruses that includes HIV. Retroviruses spread by taking over your cell’s DNA.

“And the way the virus does this is with integrase. It’s responsible for inserting the genetic information of the virus, the DNA, into our chromosomes establishing the viral reservoir. Then, it uses our cells to replicate.

“Integrase is a key component that makes HIV pathogenic.”

When a person is infected with HIV, there is an initial burst of virus production. This is when integrase inserts the virus DNA into many human cells, including CD4 T-immune cells, brain cells and other lymph cells. HIV is particularly devastating to the immune system’s T-cells, which protect the body from infection.

“Most people do not die from virus replication but from secondary causes,” Grandgenett said. “Their immune system collapses and opportunistic infections and cancer are what really kill the person.”

Now, scientists have developed drugs that are very successful at managing HIV. Combinational drug therapy is particularly effective. The virus mutates so that it can quickly become resistant to a drug. But when three different drugs aim at three different targets, as in combination drug therapy, the probability of drug resistance is much smaller.

There is one catch, however. Patients must take the drugs every day. If they do not, the virus starts cycling again and within a few weeks the viral levels are back up.

Scientists continue to try to stay a step ahead of the virus, both to combat drug resistance and to develop better treatments.

To develop better drugs, scientists want to use a process called x-ray crystallography to develop a complete picture of how integrase inhibitors — the class of HIV drugs that target integrase– interact with the virus.

“We’re aiming to develop newer, better medicines,” Grandgenett said. “We want to better understand how the integrase inhibitor drugs interact with integrase.

“So far, everybody has failed to produce HIV integrase-DNA images via high resolution x-ray crystallography,” Grandgenett said. “No one has ever captured the mother load.”

This is Grandgenett’s goal.

“Now, we’re going after full length integrase protein with DNA,” Grandgenett said. “This is what I’ve wanted to do since 1978, even before HIV was identified.”

To do this, Grandgenett and his team, including investigators Krishan Pandey, Ph.D., and Sibes Bera, Ph.D., needed to develop an integrase-DNA complex and then kinetically stabilize the complex in the presence of the drug.

Researchers used a surrogate virus to take a shortcut. Because integrase structures are similar in all retroviruses, Grandgenett tried his approach in Rous sarcoma virus (RSV), whose integrase is more readily manipulated than HIV integrase.

All current clinical integrase inhibitors work in the same way: They block integrase which prevents HIV from replicating. Specifically, they do this by stopping viral DNA strand transfer with STIs — strand transfer inhibitors.

Those inhibitors work by binding three components together: viral DNA; viral integrase; and the drug itself. Before this study, no one had been able to produce a synaptic complex (SC) in solution, the place where these three elements meet.

The researchers developed conditions where the HIV strand transfer inhibitors (STIs) trapped the SC of the surrogate RSV integrase. Grandgenett reports that this experiment is first time anyone has ever captured an integrase-DNA-inhibitor SC in solution.

“We’ve isolated it and now we want to do x-ray crystallography on it to get a better image of HIV integrase,” Grandgenett said. “That’s the next step. Hopefully, that crystal structure will better explain how integrase drugs and DNA interact at the nanometer level.

“This will help us to design new drugs. There will be a lot of uses for this information.”

source : http://www.sciencedaily.com/releases/2014/08/140806095153.htm