Forum for Science, Industry and Business

Sponsored by:     3M 
Search our Site:

 

Duke chemists find possible reason why redheads have more skin cancer

30.08.2005


A Duke University chemist has found differences in how ultraviolet light affects the photochemistry of human pigments that he says may explain why red-haired people are more prone to skin cancer than those with black hair.

Duke chemistry professor John Simon and his collaborators used a broadly-tunable ultraviolet laser and a special microscope to distinguish between the oxidation potentials of pigments of redheaded and black-haired people. Oxidation potentials measure how likely chemicals are to activate oxygen by taking up electrons.

"We were very interested in determining if there are differences in the ability of the two kinds of human pigments to activate oxygen," Simon said in an interview. "Activating oxygen can produce compounds called radicals that put oxidative stress on cells. Such stress could ultimately lead to cancer and other diseases."



Simon will describe his work in a talk at the first session on Frontiers of Photobiology that begins at 8:20 a.m. Eastern Time on Sunday, Aug. 28, 2005, in Room 143C at the Washington D.C. Convention Center during the 230th national meeting of the American Chemical Society.

Aspects of this work were originally funded by the National Institute of General Medical Sciences and are now supported by Duke University and the Air Force Office of Scientific Research.

"Red-haired, fair skinned people have a higher instance of skin cancer than black-haired individuals," Simon said. "And the melanin pigment in the skin of red haired people differs chemically from the melanin in the skin of those with black hair. So researchers have tried to compare the red with the black pigments, but have not succeeded in comparing the isolated human pigments until now."

Melanins in pigment-producing cells known as melanocytes have proved difficult to isolate from human skin, he explained. "So scientists have developed techniques to make synthetic pigments in the laboratory," Simon explained. "However, those pigments are not structurally similar to what is found in humans."

But in 2000 an Italian research team reported a method for extracting intact melanin-containing structures, called melanosomes, from human hair. Simon’s group at Duke then used that method to "isolate what I think were the first quantities of intact human black and red melanosomes amenable to study by a variety of analytical techniques," he recalled.

Their next step, to fully characterize the two pigment types, was done collaboratively with the research group of pigment cell chemist Shosuke Ito at the Fujita Health University in Japan.

While researchers confirmed that the samples were high quality and reflected those found in nature, measuring their oxidation potentials proved to be a challenge. "Basically, those measurements could not be made using the standard approaches of solution or solid state electrochemistry," Simon said.

One of his postdoctoral investigators, Alexander Samokhvalov, suggested skirting that problem with a technique called photoelectron emission. Photoelectron emission is commonly used to measure oxidation potentials in the dry thin films within solar cells when those films receive light of just the right wave length needed to release an electron.

But the researchers knew that melanosomes’ oxidation potentials would still be difficult to measure with this technique, according to Simon. They would need a laser that could be adjusted, or "tuned," to a variety of wavelengths in part of the ultraviolet portion of the light spectrum. Finding a conventional laser that could be tuned so broadly in the ultraviolet spectrum would be "difficult to impossible," he said.

Fortunately, widely tunable ultraviolet light was available at Duke’s Free-Electron Laser Laboratory (FELL). There, magnets manipulate electrons freed of their usual association with atoms to produce light at a large variety of wavelengths.

Simon’s group also learned that a team headed by Robert Nemanich at North Carolina State University had installed a photoelectron emission microscope at FELL that could resolve the tiny pigment granules.

But that microscope operates in conditions very different from the human body, including a high vacuum. So Simon’s group collaborated with Nemanich and FELL director Glenn Edwards to devise a way to study the melanosomes in such an environment.

"We found the melanosomes survived, were robust, and weren’t affected by the experimental procedure," he said. "So we went ahead and measured the photoelectron emission properties of the different human pigments."

The group found that the pigment produced by cells in black-haired people has an oxidation potential "indicating that it’s thermodynamically unfavorable for black melanosomes to activate oxygen," Simon said.

By contrast, "we found it is thermodynamically favorable for red melanosomes to activate oxygen," he said.

"Whether or not this is important in what happens in cellular systems is an open question and the subject of future work," Simon cautioned. "However, studies on melanocytes reported by other groups are consistent with these findings.

"This is the first measurement to ever be reported that compared the two human pigments, and also clearly links the red pigments to possible oxidative stress through their electrochemical properties."

Monte Basgall | EurekAlert!
Further information:
http://www.duke.edu

More articles from Life Sciences:

nachricht Link Discovered between Immune System, Brain Structure and Memory
26.04.2017 | Universität Basel

nachricht Researchers develop eco-friendly, 4-in-1 catalyst
25.04.2017 | Brown University

All articles from Life Sciences >>>

The most recent press releases about innovation >>>

Die letzten 5 Focus-News des innovations-reports im Überblick:

Im Focus: Making lightweight construction suitable for series production

More and more automobile companies are focusing on body parts made of carbon fiber reinforced plastics (CFRP). However, manufacturing and repair costs must be further reduced in order to make CFRP more economical in use. Together with the Volkswagen AG and five other partners in the project HolQueSt 3D, the Laser Zentrum Hannover e.V. (LZH) has developed laser processes for the automatic trimming, drilling and repair of three-dimensional components.

Automated manufacturing processes are the basis for ultimately establishing the series production of CFRP components. In the project HolQueSt 3D, the LZH has...

Im Focus: Wonder material? Novel nanotube structure strengthens thin films for flexible electronics

Reflecting the structure of composites found in nature and the ancient world, researchers at the University of Illinois at Urbana-Champaign have synthesized thin carbon nanotube (CNT) textiles that exhibit both high electrical conductivity and a level of toughness that is about fifty times higher than copper films, currently used in electronics.

"The structural robustness of thin metal films has significant importance for the reliable operation of smart skin and flexible electronics including...

Im Focus: Deep inside Galaxy M87

The nearby, giant radio galaxy M87 hosts a supermassive black hole (BH) and is well-known for its bright jet dominating the spectrum over ten orders of magnitude in frequency. Due to its proximity, jet prominence, and the large black hole mass, M87 is the best laboratory for investigating the formation, acceleration, and collimation of relativistic jets. A research team led by Silke Britzen from the Max Planck Institute for Radio Astronomy in Bonn, Germany, has found strong indication for turbulent processes connecting the accretion disk and the jet of that galaxy providing insights into the longstanding problem of the origin of astrophysical jets.

Supermassive black holes form some of the most enigmatic phenomena in astrophysics. Their enormous energy output is supposed to be generated by the...

Im Focus: A Quantum Low Pass for Photons

Physicists in Garching observe novel quantum effect that limits the number of emitted photons.

The probability to find a certain number of photons inside a laser pulse usually corresponds to a classical distribution of independent events, the so-called...

Im Focus: Microprocessors based on a layer of just three atoms

Microprocessors based on atomically thin materials hold the promise of the evolution of traditional processors as well as new applications in the field of flexible electronics. Now, a TU Wien research team led by Thomas Müller has made a breakthrough in this field as part of an ongoing research project.

Two-dimensional materials, or 2D materials for short, are extremely versatile, although – or often more precisely because – they are made up of just one or a...

All Focus news of the innovation-report >>>

Anzeige

Anzeige

Event News

Expert meeting “Health Business Connect” will connect international medical technology companies

20.04.2017 | Event News

Wenn der Computer das Gehirn austrickst

18.04.2017 | Event News

7th International Conference on Crystalline Silicon Photovoltaics in Freiburg on April 3-5, 2017

03.04.2017 | Event News

 
Latest News

Scientist invents way to trigger artificial photosynthesis to clean air

26.04.2017 | Materials Sciences

Ammonium nitrogen input increases the synthesis of anticarcinogenic compounds in broccoli

26.04.2017 | Agricultural and Forestry Science

SwRI-led team discovers lull in Mars' giant impact history

26.04.2017 | Physics and Astronomy

VideoLinks
B2B-VideoLinks
More VideoLinks >>>