Anxiety increases cancer severity in mice

Thursday, April 26, 2012

Worrywarts, fidgety folk and the naturally nervy may have a real cause for concern: accelerated cancer. In a new study led by researchers at the Stanford University School of Medicine, anxiety-prone mice developed more severe cancer then their calm counterparts.

The study, to be published online April 25 in PLoS ONE, found that after hairless mice were dosed with ultraviolet rays, the nervous ones ? with a penchant for reticence and risk aversion ? developed more tumors and invasive cancer. Consistent anxiety also came with sensitivity to chronic stress and a dampened immune system. Though other researchers have already linked chronic stress to higher risks for cancer and other maladies, the study is the first to biologically connect the personality trait of high anxiety to greater cancer threats.

"Anxiety may be defined as increased sensitivity to physically existent, or non-existent but perceived or anticipated, stressors," said stress expert and immunologist Firdaus Dhabhar, PhD, first author of the study.

Dhabhar's previous work has investigated the balance of "good" and "bad" stress. Short-lived stressors ? like being chased by a lion, or giving a weighty presentation to your boss ? can actually boost your immune system by preparing your body for battle. But constant stress, such as caring for a disabled loved one, breaks down the body's ability to fight off disease over time, he said.

The question is: How much stress is too much? Because stress responses vary between individuals, Dhabhar turned to understanding the link between base-level anxiety and actual stress.

For mice, stress comes from striking a balance between exploring to find food and mates, and protecting themselves from danger. Highly anxious mice, Dhabhar hypothesized, would err on the side of avoiding danger. He and his research team placed hairless mice on a raised, cross-shaped track, which had one walkway enclosed by walls and the other open. Then they measured how often each mouse ventured to the open arms. Likewise, he placed them in a large box, half lit and half dark, and noted those that spent the most time in the dark side.

"It's similar to the idea that if someone is very anxious they may be more worried about, and less likely to, walk down a dark alley," said Dhabar, an associate professor of psychiatry and behavioral sciences and a member of the Stanford Cancer Institute and the Stanford Institute for Immunity, Transplantation and Infection.

With their evaluation of anxiety complete, the researchers exposed all the hairless mice to UV rays for 10-minute bouts, three times a week, for 10 weeks ? exposure similar to that of humans who spend too much time in the sun. Tumors cropped up a few months afterward. "This skin cancer model is really valuable," Dhabhar said, "because it closely mimics human skin cancer."

Additionally, these types of tumors are vulnerable to an immune system attack. In some cases, the immune system could destroy them, he said.

Though all the mice eventually developed skin cancer, the anxious mice had more tumors and were the only ones to develop invasive forms of cancer.

When he and his team compared the immune responses of the low- and high-anxiety mice, they found that nervous mice had higher levels of immune-suppressing cells called regulatory T cells, which normally thwart overzealous responses. The high-strung mice were also making fewer of the chemical signals that fire up an immune attack on the tumors.

Lastly, the researchers looked at the hormone corticosterone. In mice and other animals, the adrenal system ? the "fight or flight" controller of the body ? secretes corticosterone in response to disease and stress. The levels of this hormone were cranked up in anxious mice, suggesting that they have more sensitive stress sensors and, perhaps, a lower threshold for feeling under the gun.

"Identifying a psychological trait right at the beginning ? before any experimental manipulation ? and seeing that it can be associated with increased tumors months later, and with biology that can begin to explain mechanisms, was a rewarding surprise," Dhabhar said.

This hasn't been tested in humans yet, and that needs to be done, Dhabhar said.

"It's bad enough that cancer diagnosis and treatment generates stress and anxiety, but this study shows that anxiety and stress can accelerate cancer progression, thus perpetuating a vicious cycle," Dhabhar said. "The goal is to ameliorate or eliminate the effects of anxiety and chronic stress, at least at the time of cancer diagnosis and during treatment."

The team's next step will be examining whether knocking down the negative effects of anxiety and stress can increase the benefits of cancer treatment. A shot of anxiety medication, such as Valium, for limited periods of time may be helpful, Dhabhar said. There may also be combinations of drugs and behavioral changes that could be most effective in the long run. "Ultimately," he said, "we really want to harness the patient's mind and body while doing everything that medicine can from the outside to maximize treatment success."

###

Stanford University Medical Center: http://med-www.stanford.edu/MedCenter/MedSchool

Thanks to Stanford University Medical Center for this article.

This press release was posted to serve as a topic for discussion. Please comment below. We try our best to only post press releases that are associated with peer reviewed scientific literature. Critical discussions of the research are appreciated. If you need help finding a link to the original article, please contact us on twitter or via e-mail.

This press release has been viewed 23 time(s).

Easy Airbeds portland home inspectors lasik laser treatment Chicago family law attorney palm harbor

Rumeur : des images du nouveau bouton Home de l'iPhone 5

mardi 24 avril 2012 ? 8H15
image:http://assets.branchez-vous.net/admin/images/techno/iphone4s-three-units225.png

Comme vous le savez s?rement, si vous visitez r?guli?rement ce blogue, chez Apple, on aime les rumeurs. La derni?re en date concerne le bouton Home du tr?s attendu iPhone 5.

Des images de ces nouveaux boutons ont commenc? ? circuler, il y a quelques jours, sur la Toile. En fait, elles proviennent d'un site d'un fournisseur chinois, TVC-Mall.com, qui a mis en vente les fameux boutons. La section du site consacr?e ? cette composante est maintenant vide.

Quand on regarde les images de cette nouvelle pi?ce, on se rend vite compte qu'il n'y a pas de r?volution. La plus grande diff?rence entre le nouveau bouton et celui de l'iPhone 4 concerne la forme. En effet, le bouton de l'iPhone 5 serait rond ? son centre et carr? ? l'ext?rieur. Rappelons que le bouton de l'iPhone 4 est, quant ? lui, de forme ronde.

Cette nouvelle pi?ce serait disponible en noir et en blanc, des couleurs tr?s ? la mode chez la marque ? la pomme.

Si cette rumeur est fond?e, plusieurs croient que le nouveau t?l?phone de la firme de Cupertino ne pr?senterait pas les am?liorations souhait?es en termes de design. Certains auraient bien aim? voir dispara?tre le fameux bouton Home, qui est install? dans la plupart des appareils nomades d'Apple.

Mais doit-on croire cette rumeur? Il est pour l'instant difficile de le dire. Mentionnons simplement que ce site Internet de la Chine avait commenc? ? vendre des pi?ces du nouvel iPad, comme des antennes Bluetooth, en janvier dernier, soit avant le lancement officiel de la nouvelle tablette d'Apple.


Images provenant du site TVC-Mall.com.

Sources : Macrumors et AppleBitch.com.


Suivez BRANCHEZ-VOUS! sur

----Suivez Philippe Michaud sur Twitter! (@Micph)----

par Philippe Michaud

DERNIERS ARTICLES DU BLOGUE


ABONNEZ-VOUS GRATUITEMENT

Maternity Pants neck pain relief Lexington las cruces homes Slushy Machine Hire Perth

12 Mechanical Flight Sims from Aerospace's Analog Era [Design]

And you thought testing the F-117 was a feat? In the days before building a full-scale 737 mock-up in your garage was possible, flight schools and even NASA relied on mechanical simulators to train pilots. Our friends at Oobject have collected 12 of the most advanced simulators of the day. More »


homeowners insurance philadelphia mesilla real estate lawyer Timber gluts

5 best new iOS, Android applications for April 2012

1. Google Drive

Google Drive is a cloud storage services and it?s tightly integrated into Android. Also, it offers 5 gigs of storage for free, so there?s no reason why you wouldn?t try it. Of course, it faces some tough competition from existing similar services. So if you?re still trying to figure out which is the best app for moving your files to the cloud, check out our detailed comparison of Google Drive and other cloud apps here.

2. 500px

If there?s a photo aggregator that comes close to visual perfection in its app form, 500px has got to be it. A community known for the huge amount of professional photographers uploading pictures to it and for the freedom it offeres (one can upload all kinds of pictures, nu included), it?s definitely something you won?t regret trying out.

500px

3. Pocket

Formerly known as Read It Later, Pocket is not exactly a new application for April, but a huge redesign and a change of titles allowed it to enter our top five. And for a good reason, it?s one of those apps that would let you procrastinate your reading in an elegant way and maybe even focus on work. It brings your list of unread articles, unseen videos and undone things to smartphones, tablets, and desktop/laptop PCs.
Download Pocket on Android
Download Pocket for iPhone/iPad

4. Next Issue

Next Issue is an application that gives you access to tons of popular magazines for one relatively low monthly price. $10 a month gives you access to a huge number of magazines, and for a $5 premium you get access to some of the best writing in the English press. Currently Android-only, the application is expected arrive to iPad soon.

5. Instagram for Android

Instagram is one application we won?t surprise you with. If for some reason you?ve missed the huge news - in April it arrived on Android, plus got acquired for $1 billion by Facebook. Not bad for an app that disguises your pictures into retro filters, is it?

Instagram for Android

cigar lighter commercial roofing companies dallas wine boxes law

Union rules keep New York City from removing teachers from schools, but Mayor Mi...

Go Mayor - Wish you were in TX. Remove sovereign immunity and Teachers union. Our Children need rights to a safe caring non hostile environment! To heck with teachers rights to privacy in classrooms alone with our children = no video camer...as allowed. They wont follow their own policy to protect victims from bullies = TEC Ch 37 to remove violent students to DAEP They wont make true reports of assault call it mutual combat to their jobs. They want to appear clean on safety reports. kids are commiting suicide and have no rights to legal representation. YET, our parents tax dollars pay attorneys to defend the schools NOT STUDENTS RIGHTS TO SAFETY AT SCHOOL! SIGN JOHNNYS PETITION 3yrs of assault denied by KISD 42 school nurse logs of evidence denied. http://coxxranch.com/stop_bullies_84.htmlSee More

Buy Makeup Online Palmetto Bluff Real Estate vanity sets start a dog business