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Insight into the anti-cancer effect of exercise
Last Updated: 2006-05-29 9:00:53 -0400 (Reuters Health)
By Martha Kerr
NEW YORK (Reuters Health) - The anti-cancer effects of exercise are due to increases in a protein that blocks cell growth and induces cell death, according to Australian researchers.
The protein, called insulin-like binding protein-3 (IGFBP-3), inhibits another protein called insulin-like growth factor-1 (IGF-1), thereby blocking IGF-1's proliferative effect on cell growth, the study hints.
Dr. Andrew M. M. Haydon and colleagues at Manash Medical School in Melbourne identified new cases of colorectal cancer in the Melbourne Collaborative Cohort Study, a prospective study of 41,528 adults recruited between 1990 and 1994.
The investigators looked at baseline body mass index and level of physical activity reported and compared baseline levels of IGF-1or IGFBP-3 with those measurements.
Analyses centered on 443 colon cancer patients followed for more than 5 years.
Among subjects who were physically active, an increase in IGFBP-3 was associated with a 48 percent reduction in colon cancer-specific deaths. No association was apparent for IGF-1.
For the physically inactive, there was no association between IGF-1 or IGFBP-3 and colon cancer survival.
Haydon told Reuters Health that that "physical activity can increase IGFBP-3 levels, which, in turn, reduces the amount of free IGF-1." IGF-1 has been shown to stimulate cell growth, inhibit cell death, and promote angiogenesis -- the formation of new blood vessels, which tumors need to grow.
"We did not look at the amount of physical activity needed to reduce colorectal cancer incidence, as we only looked at those from our cohort who had CRC," Haydon pointed out.
"Other studies that have looked at this have shown a dose-effect, meaning the more exercise the lower the risk, however our study did not try to address this issue. We were examining the effect of physical activity on one's prognosis following a diagnosis of bowel cancer and the possible mechanisms behind this effect."
SOURCE: Gut, May 2006.
Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
WHO puts Roche on Tamiflu alert for Indonesia
Last Updated: 2006-05-29 13:34:01 -0400 (Reuters Health)
GENEVA, May 27 - The World Health Organisation (WHO) said on Saturday it had asked Swiss drug manufacturer Roche to prepare to ship Tamiflu to Indonesia, but had not requested that any of the anti-bird flu drug be sent.
WHO spokeswoman Maria Cheng said it was standard procedure to ensure drugs were ready for shipment when a cluster of infections occurred, such as that in Indonesia where the H5N1 virus has killed as many as eight family members this month.
"Whenever there is a cluster, we contact Roche just to let them know that if we need to send the stockpile that they should be ready to do so," Cheng said.
"We have not asked that anything be sent, and nothing from Roche has been sent," she added.
Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
Multi-pronged approach curbs risky sex in the HIV+
Last Updated: 2006-05-29 13:00:39 -0400 (Reuters Health)
By Anne Harding
NEW YORK (Reuters Health) - Programs intended to help individuals infected with HIV, the virus that causes AIDS, to reduce their sexual risk work best if they include training on skills like how to use a condom, as well as motivational training designed to boost social support or otherwise improve overall quality of life, a review of studies suggests.
But Dr. Blair T. Johnson of the Center for Health/HIV Intervention and Prevention at the University of Connecticut in Storrs and colleagues found that interventions including skills and motivational components have actually not been tested in HIV-positive men who have sex with men. "We don't really know how good prevention could be with them," Johnson told Reuters Health.
Motivational components might include information that would help an HIV-positive person feel optimistic about the future, Johnson explained. Basically, this approach is intended to give a person a sense that it's worth it to "keep their guard up and act safe," he added.
Johnson and his team reviewed 15 studies including a total of 3,234 participants, all of which tested the effectiveness of a particular approach to reducing sexual risk behavior among HIV-infected individuals. To date, they note in their report in the Journal of the Acquired Immune Deficiency Syndromes, evidence for such programs' effectiveness has been "mixed."
On average, the researchers found, the interventions increased participants' condom use by 16 percent, but had no effect on their number of sexual partners. The programs' effectiveness varied widely. Those that included a motivational component and skills training along with information on risk increased condom use by 32 percent, compared to just 5 percent for interventions that provided information only.
Younger people also showed more of a response to the interventions. Twenty-year-olds were 53 percent more likely to use condoms, on average, after participating, compared to an 11 percent increase in condom use among 40-year-olds.
Johnson and his team hypothesize that older people may tend to be in longer-term partnerships, "a factor that is known to increase resistance to change."
Overall, the researchers found, interventions were not effective for men who have sex with men. But because none of the studies that included this population featured motivational and skills components, they add, it's not clear if these approaches would be helpful, and there's no evidence to show that men who have sex with men are as a rule less responsive to such efforts.
"Perhaps the most surprising finding of this work is that more than two decades into the epidemic, there have been so few intervention randomized controlled trials that focus on people living with HIV," the researchers note.
However, Johnson told Reuters Health, several such trials are underway. "I think this problem will be rectified very soon."
SOURCE: Journal of Acquired Immune Deficiency Syndromes, April 15, 2006 .
Copyright © 2006 Reuters Limited. All rights reserved. Republication or redistribution of Reuters content, including by framing or similar means, is expressly prohibited without the prior written consent of Reuters. Reuters shall not be liable for any errors or delays in the content, or for any actions taken in reliance thereon. Reuters and the Reuters sphere logo are registered trademarks and trademarks of the Reuters group of companies around the world.
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