Navigation Links
Intense terahertz pulses cause DNA damage but also induce DNA repair
Date:3/14/2013

Terahertz (THz) radiation, a slice of the electromagnetic spectrum that occupies the middle ground between microwaves and infrared light, is rapidly finding important uses in medical diagnostics, security, and scientific research. As scientists and engineers find evermore practical uses for this form of radiation, questions persist about its potential human health risks.

New research performed on lab-grown human skin suggests that short but powerful bursts of THz radiation may both cause DNA damage and increase the production of proteins that help the body fight cancer. The findings, which are the result of a collaboration between physicists at the University of Alberta and molecular biologists at the University of Lethbridge in Canada, are published today in the Optical Society's (OSA) open-access journal Biomedical Optics Express.

"While these investigations of the biological effects of intense THz pulses are only just beginning," said Lyubov Titova, with the University of Alberta and a member of the research team, "the fact that intense THz pulses can induce DNA damage but also DNA repair mechanisms in human skin tissue suggests that intense THz pulses need to be evaluated for possible therapeutic applications."

THz photons, like their longer wavelength cousins in the microwave range, are not energetic enough to break the chemical bonds that bind DNA together in the nucleus of cells. These waves, however, have just the right frequency to energize water molecules, causing them to vibrate and produce heat, which is why microwave ovens are so efficient at cooking food. For this reason, it was believed that heat-related injuries were the principal risks posed by THz radiation exposure.

Recent theoretical studies, however, suggest that intense THz pulses of picosecond (one trillionth of a second) duration may directly affect DNA by amplifying natural vibrations (the so-called "breathing" mode) of the hydrogen bonds that bind together the two strands of DNA. As a result, "bubbles" or openings in DNA strands can form. According to the researchers, this raised the question: "Can intense THz pulses destabilize DNA structure enough to cause DNA strand breaks?"

As shown in earlier animal cell culture studies, THz exposure may indeed affect biological function under specific conditions such as high power and extended exposure. There is, however, a vast gulf between animal research and conclusions that can be drawn about human health.

In a first of its kind study, the Canadian researchers exposed laboratory-grown human skin tissue to intense pulses of THz electromagnetic radiation and have detected the telltale signs of DNA damage through a chemical marker known as phosphorylated H2AX. At the same time, they observed THz-pulse induced increases in the levels of multiple tumor suppressor and cell-cycle regulatory proteins that facilitate DNA repair. This may suggest that DNA damage in human skin arising from intense picosecond THz pulse exposure could be quickly and efficiently repaired, therefore minimizing the risk of carcinogenesis.

The researchers used a skin tissue model made of normal, human-derived epidermal and dermal cells. This tissue is able to undergo mitosis (cell division) and is metabolically active, thus providing an appropriate platform for assessing the effects of exposure to high intensity THz pulses on human skin. For their study, Titova and her colleagues exposed the skin tissue to picosecond bursts of THz radiation at levels far above what would typically be used in current real-world applications. They then studied the sample for the presence of phosphorylated H2AX, which "flags" the DNA double strand break site and attracts cellular DNA repair machinery to it.

"The increase in the amount of phosphorylated H2AX in tissues exposed to intense THz pulses compared to unexposed controls indicated that DNA double strand breaks were indeed induced by intense THz pulses," observed Titova. Once DNA breaks occur, they can eventually lead to tumors if unrepaired. "This process," she continued, "is very slow and cells have evolved many effective mechanisms to recognize damage, pause cell cycle to allow time for damage to be repaired, and in case repair is unsuccessful to prevent damage accumulation by inducing apoptosis, or programmed cell death of the affected cell."

The researchers confirmed that these cellular repair mechanisms were taking place by detecting an elevated presence of multiple proteins that play vital roles in DNA repair, including protein p53 (often called "a guardian of the genome"); p21, which works to stop cell division to allow time for repair; protein Ku70, which helps reconnect the broken DNA strands; and several other important cell proteins with known tumor-suppressor roles. These observations indicate that exposure to intense THz pulses activates cellular mechanisms that repair DNA damage. However, the researchers note, it is too soon to make predictions on the long-term implications of exposure.

"In our study we only looked at one moment in time 30 minutes after exposure," Titova said. "In the future, we plan to study how all the observed effects change with time after exposure, which should allow us to establish how quickly any induced damage is repaired."

The Canadian researchers hope to explore the potential therapeutic effects of intense THz radiation exposure to see if directed treatment with intense THz pulses can become a new tool to fight cancer.


'/>"/>

Contact: Angela Stark
astark@osa.org
202-416-1443
The Optical Society
Source:Eurekalert  

Related medicine news :

1. Short Bursts of Intense Exercise Can Fight Weight Gain: Study
2. Intense light prevents, treats heart attacks
3. Ultra-short laser pulses for science and industry
4. Some bacteria may protect against disease caused by stomach infection
5. Single concussion may cause lasting brain damage
6. Cloth for a Cause Helps Families In Need by Providing Cloth Diapers
7. Kids Pet Frogs Caused Salmonella Outbreak: CDC
8. Sudden death in young athletes: Important causes not identified by the screening process
9. BRAF inhibitor treatment causes melanoma cells to shift how they produce energy
10. Skechers Lawsuit Filed on Behalf of an Indiana Woman, Alleging Defective Design of Shape-Ups Caused Leg Fracture, by Wright & Schulte
11. Improper protein digestion in neurons identified as a cause of familial Parkinsons
Post Your Comments:
*Name:
*Comment:
*Email:
Related Image:
Intense terahertz pulses cause DNA damage but also induce DNA repair
(Date:2/5/2016)... ... February 05, 2016 , ... Francisco Canales, ... services in their Napa Valley office. The technique utilizes the body’s own healing ... Canales and Dr. Furnas, are part of only a select few cosmetic surgeons ...
(Date:2/5/2016)... ... ... US Sports Camps , official operators of Nike Yoga Camps, announces ... training. ChildLight Yoga Studio is centrally situated in the picturesque New England city of ... founder Lisa Flynn expresses her excitement, “We are thrilled to be partnering with US ...
(Date:2/5/2016)... ... February 05, 2016 , ... Boar’s Head Brand®, one of ... for this weekend’s Big Game. Take the stress out of your party preparation – ... guests happy at every stage of the game. , “The key to hosting a ...
(Date:2/5/2016)... ... February 05, 2016 , ... ... CitiDent, announces that it is now welcoming orthodontist, Dr. Amanda Cheng, to ... a complete range of oral health care, including general dentistry, cosmetic treatments, periodontics, ...
(Date:2/5/2016)... ... February 05, 2016 , ... On June 9-10, Las ... continuing medical education (CME) event presented by the Association for Comprehensive Care in ... for ACCORD, whose mission is to provide education, tools, and resources to primary ...
Breaking Medicine News(10 mins):
(Date:2/5/2016)... , February 5, 2016 Site ... Today, VoicePower Ltd - The Speech Recognition People, announced their latest ... to improve patient care, reduce turnaround times and to save the ... ,- VoicePower client since 2013 Challenge: --> ... --> - Six doctors ,- Wirral CCG ,- VoicePower ...
(Date:2/4/2016)... , Feb. 4, 2016  Edwards Lifesciences Corporation (NYSE: ... for structural heart disease and critical care monitoring, announced ... repurchase (ASR) agreement with Morgan Stanley & Co. LLC ... repurchase is part of the Company,s previously authorized program ... common stock.  --> ...
(Date:2/4/2016)... , Feb. 4, 2016  SciClone Pharmaceuticals, Inc. ... it has entered into a settlement agreement with ... fully resolving the SEC,s investigation into possible violations ... the terms of the settlement agreement, SciClone has ... including disgorgement, pre-judgment interest and a penalty.  This ...
Breaking Medicine Technology: