Monday, November 3, 2014

Weight loss surgery 'highly effective for preventing type 2 diabetes'

OBesity is a major risk factor for type 2 diabetes, which is accountable for around 90-95% of diabetes cases in the US. But a new study claims that for obese individuals, weight loss surgery may dramatically reduce this risk.The research team, including Prof. Martin Gulliford of King's College London in the UK, publish their findings in The Lancet Diabetes & Endocrinology.
Past studies have indicated that weight loss surgery, or bariatric surgery, may be an effective strategy to treat type 2 diabetes in obese patients. But Prof. Gulliford and colleagues note there have been very few studies looking at whether weight loss surgery can prevent the development ofdiabetes in obese patients. For their study, the team wanted to find out.
They analyzed health records from the UK Clinical Practice Research Datalink and identified 2,167 obese adults without diabetes who had undergone one of three surgical procedures: gastric bypass, gastric banding or sleeve gastrectomy.
Gastric bypass, which involves redirecting the digestive system past the stomach, is the most common weight loss procedure. Gastric banding involves having an inflatable band placed around the top portion of the stomach, creating a smaller stomach, while sleeve gastrectomy involves removal of around 80% of the stomach.
To act as controls, the team also identified 2,167 obese individuals - matched for age, sex, body mass index (BMI) and blood sugar levels - who had not undergone weight loss surgery or had any other obesity-related treatments. Participants were followed for up to 7 years.

Weight loss surgery reduced type 2 diabetes risk by 80%

The researchers found that 177 of the control participants developed type 2 diabetes during follow-up, compared with only 38 participants who had undergone weight loss surgery.
The team calculated that even after accounting for other factors that influence diabetes among obese individuals - such as smoking, hypertension and high cholesterol - weight loss surgery reduced participants' risk of type 2 diabetes by 80%.
Commenting on these findings, Prof. Gulliford says: 
"Our results suggest that bariatric surgery may be a highly effective method of preventing the onset of new diabetes in men and women with severe obesity.
We need to understand how weight loss surgery can be used, together with interventions to increase physical activity and promote healthy eating, as part of an overall diabetes prevention strategy."
The researchers point out that there are some limitations to their study. For example, they did not include patients who had undergone less common weight loss procedures, such as duodenal switch - surgery that combines gastric bypass and creation of a smaller stomach pouch. Therefore, it is unclear how such procedures would affect type 2 diabetes risk in obese patients.
Furthermore, the team says that patients who underwent weight loss surgery may have been more adherent to diabetes prevention advice - such as adopting a healthy diet and exercise - than control patients. "However," they add, "we noted that people who received surgery were more likely to be prescribed antihypertensive drugs or statins, which can sometimes be associated with diabetes."
In an editorial linked to the study, Dr. Jacques Himpens, of Saint Pierre University Hospital in Belgium, says that the findings from Prof. Gulliford and colleagues bring us closer to understanding the effects of bariatric surgery for prevention of type 2 diabetes. However, she notes that "many questions remain unanswered."
"More evidence is needed to convince endocrinologists about the nature of this effect," she adds.
In February of this year, Medical News Today reported on a study revealing that although most women who undergo weight loss surgery say they do not regret having the procedure, many of them feel it causes emotional problems.
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What kinds of exercise can boost long-term memory?

Think that improving your memory is all brain training and omega-3 supplements? Think again. A new study from researchers at Georgia Institute of Technology in Atlanta suggests that working out at the gym for as little as 20 minutes can improve long-term memory.



Previous studies have shown that memory may be improved by several months of aerobic exercises, such as running, cycling or swimming. However, the findings of the new study - published in the journal Acta Psychologica - demonstrate that a similar memory boost can be achieved in a much shorter period.
"Our study indicates that people don't have to dedicate large amounts of time to give their brain a
boost," says Lisa Weinberg, the Georgia Tech graduate student who led the project.
As well as looking at aerobic exercise, Weinberg's team also examined how resistance exercise - weightlifting, push-ups and sit-ups - might affect memory.
The team recruited 46 participants (29 women and 17 men), who were randomly assigned into two groups. For the first part of the experiment, all participants viewed a series of 90 images on a computer screen.
These images were split evenly been photographs that had been classed "positive," "neutral," and "negative." These ranged from pictures of children playing on a waterslide, to photographs of clocks, to images of mutilated bodies. The participants were asked to try and remember as many of them as they could.
Next, the participants were randomized into "active" and "passive" groups and seated at leg extension resistance exercise machines.
The active group were told to extend and contract each leg 50 times, at their personal maximum effort. The passive group were told to simply sit in the chair and allow the machine to move their legs.
The blood pressure and heart rate of the participants were monitored, and saliva samples were collected.

'Active' group showed improved recall of images

Two days later, the participants were again shown the original 90 images they had seen previously, but this time they were mixed in with 90 new photos that the participants had not seen before.
The researchers found about 50% of the original photos were recalled by the passive group, while the active group remembered about 60% of the images.
All of the participants were better at recalling the positive and negative images than the neutral images, but this was even more true for the active participants. The researchers suggest that this is because people are more likely to remember emotional experiences following short-term stress.
The team believes their results are consistent with previous research in a rodent model that found stress responses result in releases of norepinephrine - a hormone that may improve memory.
Analyzing the saliva from the participants, the team found that the active group showed increased levels of alpha amylase in their saliva - a marker of norepinephrine.
Audrey Duarte, an associate professor in the School of Psychology at Georgia Tech, describes the results:
"Even without doing expensive fMRI scans, our results give us an idea of what areas of the brain might be supporting these exercise-induced memory benefits. The findings are encouraging because they are consistent with rodent literature that pinpoints exactly the parts of the brain that play a role in stress-induced memory benefits caused by exercise."

Tuesday, October 28, 2014

Important how cells copy chromosomes for fighting cancer







As we find out more and more about what goes wrong inside cells, the better we become at killing cancer without harming the rest of the body. Now, scientists have discovered a key step in how cells copy their 
chromosomes when they divide that promises to be very useful for cancer research.

Karim Labib, a professor in life sciences at the University of Dundee in Scotland, and colleagues report how they solved an important mystery in cell biology in the journal Science.
Life depends on cells being able to multiply, a key part of which is copying chromosomes, the tightly packed bundles of DNA that carry the genetic blueprint of the individual.
The chromosome copying process has to copy the genetic information perfectly for new cells to grow and carry out their function normally. The more mistakes that are made, the more likely that cells will behave abnormally and triggercancer.

We do not know enough about how chromosome copying works

cancer cell
The researchers say one of the fundamental biological processes that go wrong in cancer is that the chromosome copying machinery has not worked properly. Their new study sheds light on this process.
Prof. Labib says ever since Watson and Crick first revealed the structure of DNA, scientists have been fascinated by how cells copy chromosomes, yet "we are still quite a way from having a complete picture of how it works."
He and his colleagues focused on the stage when the cells finish copying their chromosomes. Scientists already know something about this; it is vital that this happens correctly for the genetic blueprint to be passed on to the next generation of cells.
"We already knew that 11 proteins in the cell combine to build a molecular 'machine' called the DNA helicase, which plays a vital role in copying the double helix of DNA that is at the heart of each chromosome," Prof. Labib adds.
He explains that the DNA helicase unwinds the two strands of the double helix of DNA, so they can each be copied, and that:
"It is vital that the helicase is only built once during the life of each cell, and then is taken apart or disassembled once it has done its job, so that cells just make one single copy of each chromosome."

Understanding disassembly of the DNA helicase is important for cancer research

Until now, scientists did not know how the helicase disassembled. This is what the team at Dundee discovered. They found, because of a process called "ubiquitylation," one of the 11 components of the helicase falls out when chromosome copying is complete.
Because this one component falls out, the other proteins are unable to stick together, and the DNA helicase falls apart.
"It turns out that this is a very good thing," says Prof. Labib, "as genetic studies show that if the helicase does not come apart but instead remains glued to the chromosomes, then this leads to major problems."
He says this is one of the fundamental biological processes that go wrong in cancer, "almost any time that we see cancer developing, one of the things that has gone wrong early in the process is that the chromosome copying machinery has not worked properly."
The research was funded by the Medical Reseach Council, Cancer Research UK and the Wellcome Trust.
Meanwhile, in another area of cancer research, Medical News Today recently learned that researchers have found a molecule that helps cancer cells evade the immune system.