SAN DIEGO, California, November 14, 2008 (ENS) – Human consumption of red meat and milk products can contribute to the increased risk of cancerous tumors, according to a National Cancer Institute-backed study published this week in the Proceedings of the National Academy of Sciences.

A husband-and-wife team of physician-scientists at the University of California, San Diego School of Medicine, has newly demonstrated a mechanism for how this increase in risk occurs.

A non-human, cellular molecule absorbed into human tissues as a result of eating red meat and milk products could promote tumor growth, according to the team led by Ajit Varki, M.D. and his wife, Nissi Varki, M.D.

The molecule, called N-glycolylneuraminic acid (Neu5Gc), is a type of glycan, or sugar molecule, that humans do not naturally produce, but that can be incorporated into human tissues as a result of eating red meat.

Not produced in humans, Neu5Gc occurs naturally in lamb, pork and beef, with the highest levels found in beef and beef fat. Levels are very low or undetectable in fruits, vegetables, eggs, poultry and fish.

Beef contains the highest amount of a
molecule that could trigger the formation
of cancerous tumors. (Photo credit unknown)

When foods containing Neu5Gc are eaten, the body then develops anti-Neu5Gc antibodies – an immune response that could potentially lead to chronic inflammation, as first suggested in a 2003 paper by Aji Varki also published in the Proceedings of the National Academy of Sciences.

The Varkis’ research suggests that inflammation resulting from this molecule could promote tumor growth.

“We’ve shown that tumor tissues contain much more Neu5Gc than is usually found in normal human tissues,” said Ajit Varki. “We therefore surmised that Neu5Gc must somehow benefit tumors.”

It has been recognized by scientists for some time that chronic inflammation can actually stimulate cancer, he explained. So the researchers wondered if this was why tumors containing the non-human molecule grew even in the presence of Neu5Gc antibodies.

“The paradox of Neu5Gc accumulating in human tumors in the face of circulating antibodies suggested that a low-grade, chronic inflammation actually facilitated the tumor growth, so we set out to study that hypothesis,” said Nissi Varki M.D., UCSD professor of pathology.

Using specially bred mice that lacked the Neu5Gc molecule – mimicking humans before the molecule is absorbed into the body through ingesting red meat – the researchers induced tumors containing Neu5Gc, and then administered anti-Neu5Gc antibodies to half of the mice.

In mice that were given antibodies, inflammation was induced, and the tumors grew faster.

In the control mice that were not treated with antibodies, the tumors were less aggressive.

Other scientists have previously shown that humans who take non-steroidal anti-inflammatory drugs have a reduced risk of cancer. So, the mice with cancerous tumors facilitated by anti-Neu5Gc antibodies were treated with an NSAID.

In these animals, the anti-inflammatory treatment blocked the effect of the Neu5Gc antibodies and the tumors were reduced in size.

“Taken together, our data indicate that chronic inflammation results from interaction of Neu5Gc accumulated in our bodies from eating red meat with the antibodies that circulate as an immune response to this non-human molecule – and this may contribute to cancer risk,” said Ajit Varki.

Additional contributors to the paper are Maria Hedlund and Vered Padler-Karavani, UCSD Departments of Medicine and Cellular and Molecular Medicine. The study was funded in part by a grant from the National Cancer Institute of the National Institutes of Health.

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SAN DIEGO, California, October 24, 2008 (ENS) – A gas used in manufacture of flat panel televisions, computer displays, microcircuits, and thin-film solar panels is 17,000 times more potent a greenhouse gas than carbon dioxide, and it is far more prevalent in the atmosphere than previously estimated.

The powerful greenhouse gas nitrogen trifluoride, NF3, is at least four times more widespread than scientists had believed, according to new research by a team at Scripps Institution of Oceanography at the University of California, San Diego.

Using new analytical techniques, a team led by Scripps geochemistry professor Ray Weiss made the first atmospheric measurements of nitrogen trifluoride, NF3.

“Accurately measuring small amounts of NF3 in air has proven to be a very difficult experimental problem, and we are very pleased to have succeeded in this effort,” Weiss said Thursday, announcing the results of his team’s research.

The research findings will be published October 31 in “Geophysical Research Letters,” a journal of the American Geophysical Union.

Scripps geoscientists Ray Weiss, left, and Jens
Muehle show cylinders used to collect air
samples that they analyzed for
concentrations of nitrogen trifluoride.
(Photo courtesy Scripps Institution of
Oceanography, UC San Diego)

The amount of the gas in the atmosphere, which could not be detected using previous techniques, had been estimated at less than 1,200 metric tons in 2006. The new research shows the actual amount was 4,200 metric tons.

In 2008, about 5,400 metric tons of the gas was in the atmosphere, a quantity that is increasing at about 11 percent per year.

This rate of increase means that about 16 percent of the amount of the gas produced globally is being emitted into the atmosphere, the researchers estimate.

Emissions of NF3 were thought to be so low that the gas was not considered to be a significant potential contributor to global warming.

Nitrogen trifluoride was not covered by the Kyoto Protocol, the 1997 agreement to reduce greenhouse gas emissions signed by 182 countries, although three other fluoride compounds are covered.

The protocol governs the emissions of carbon dioxide, methane, and nitrous oxide as well as other fluoride compounds – sulfur hexafluoride, hydrofluorocarbons, and perfluorocarbons.

In response to the growing use of the gas and concerns that its emissions are not well known, the scientists have recommended adding it to the list of greenhouse gases regulated by the protocol or its successor agreement now under negotiation.

“From a climate perspective, there is a need to add NF3 to the suite of greenhouse gases whose production is inventoried and whose emissions are regulated under the Kyoto Protocol, thus providing meaningful incentives for its wise use,” said Weiss.

Nitrogen trifluoride is one of several gases used during the manufacture of liquid crystal flat-panel displays, thin-film photovoltaic cells and microcircuits.

Many industries have used the gas in recent years as an alternative to perfluorocarbons, which are also potent greenhouse gases, because it was believed that no more than two percent of the NF3 used in these processes escaped into the atmosphere.

To obtain their information, the Scripps team analyzed air samples gathered in California and Tasmania over the past 30 years by the NASA-funded Advanced Global Atmospheric Gases Experiment network of ground-based stations.

The network was created in the 1970s in response to international concerns about chemicals depleting the ozone layer. It is supported by NASA as part of its congressional mandate to monitor ozone-depleting trace gases, many of which are also greenhouse gases.

The researchers found concentrations of NF3 rose from about 0.02 parts per trillion in 1978 to 0.454 parts per trillion in 2008.

Higher concentrations of NF3 were found in the Northern Hemisphere than in the Southern Hemisphere, which the researchers said is consistent with its greater use in Northern Hemisphere countries.

“This result reinforces the critical importance of basic research in determining the overall impact of the information technology industry on global climate change, which has already been estimated to be equal to that of the aviation industry,” said Larry Smarr, director of the California Institute for Telecommunications at University of California, San Diego, who was not involved in the Scripps study.

Michael Prather is a University of California, Irvine atmospheric chemist who predicted earlier this year that based on the rapidly increasing use of NF3, larger amounts of the gas would be found in the atmosphere. Prather said the new Scripps study provides the confirmation needed to establish reporting requirements for production and use of the gas.

“I’d say case closed. It is now shown to be an important greenhouse gas,” said Prather, who was not involved with the Scripps study. “Now we need to get hard numbers on how much is flowing through the system, from production to disposal.”

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SAN DIEGO, California, July 16, 2008 (ENS) – The University of California-San Diego calls itself “one of the nation’s greenest college campuses,” and to enhance that status, the university has begun to install the components of a multi-faceted sustainable energy program.

The university will soon be generating 7.4 megawatts of green energy, providing 10 to 15 percent of its own annual electrical usage.

The far-reaching program, which includes solar panels, biogas fuel cells and wind energy, began with the first installation of solar photovoltaic panels atop a campus utility plant.

Soon, buildings and parking garages across the 1,200-acre campus next to the Pacific Ocean will feature solar panels.

Workers install solar panels on a roof
at the University of California-San
Diego. (Photo courtesyUC-San Diego)

UC San Diego’s green energy capacity will eventually produce 29 million kilowatt hours a year, which is enough to provide electricity for more than 4,500 homes a year.

The amount of renewable energy is like removing 10,500 tons of carbon dioxide from the atmosphere each year, or removing 1,500 cars a year from the roads.

“This photovoltaic installation marks an historic event for a campus that has become a living laboratory for climate change solutions,” said Steve Relyea, vice chancellor of business affairs.

“Our sustainable energy program is the result of a campuswide commitment by students, faculty and administration to advance environmental sustainability on a local, national and global level,” he said.

This year the Scripps Institution of Oceanography at UC San Diego is celebrating the 50th anniversary of the Keeling Curve, the first measurement of greenhouse gas build-up, which was conducted by Scripps scientist Charles David Keeling.

Researchers and students at UC San Diego are working on a wide range of environmental sustainability projects. They are developing biofuels from algae and wood debris.

Planners design green dorms with automatic sun shading to save energy and drainage systems that stop all storm runoff from flowing into the nearby ocean.

Students and fleet managers have begun a biofuel shuttle bus line, which decreases UC San Diego’s reliance on greenhouse gas-generating fossil fuels.

The world’s top climate change researchers and post-docs are working to discover the impact of Asian brown cloud pollution on global climate and of rising temperatures on the western U.S. water supply.

UC San Diego’s green energy program will continue to unfold over the next year, as the first megawatt of solar photovoltaic panels is constructed and a second megawatt is planned and implemented.

Construction begins this fall on a project that will allow UC San Diego to produce another 2.4 megawatts of energy from fuel cells powered by renewable methane. The methane fuel will be transported to UC San Diego from the Point Loma sewage treatment plant, where it is produced.

Not only does this produce green energy that replaces carbon-based energy, but it also removes pollutants from local air, since the methane is currently flared into the atmosphere at the sewage plant.

UC San Diego also begins a unique program to swap fossil fuel-generated energy for wind power.

The university will throttle back its natural gas-powered cogeneration plant at night and replace the power with electricity purchased from California wind farms.

This project, the first of its kind in California, will generate up to three megawatts of green energy.

The solar photovoltaic and biogas fuel cell construction projects are cost-free for the university.

UC San Diego has negotiated power purchase agreements, in which investors construct, install and maintain the photovoltaic panels and fuel cells on campus property, and the university then buys the power from investors through long-term contracts.

UC San Diego has teamed up with local, national and international companies on its sustainable energy project.

Three partners are working with the university on the solar photovoltaic project. Borrego Solar, Inc., a national solar power contractor based in El Cajon, California, is the installer; Envision Solar, Inc., of San Diego is the designer of the solar “trees” that will be built on top of UC San Diego parking structures. Solar Power Partners Inc., of Mill Valley is the financier and owner of the solar photovoltaic arrays.

The biogas fuel cells are financed, constructed and owned by The Linde Group, an international industrial gases and engineering company.

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SAN DIEGO, California, March 23, 2008 (ENS) – Black carbon, particulate matter in the air produced by diesel exhaust, biomass burning, and cooking with solid fuels, has a warming effect in the atmosphere three to four times greater than existing estimates, according to scientists in an upcoming review article in the journal “Nature Geoscience.”

Atmospheric scientist V. Ramanathan with the Scripps Institution of Oceanography at University of California-San Diego and University of Iowa chemical engineer Greg Carmichael, said that soot and other forms of black carbon could have as much as 60 percent of the current global warming effect of carbon dioxide, more than that of any greenhouse gas besides carbon dioxide, CO2.

The researchers also say that mitigation would have immediate societal benefits in addition to the long-term effect of reducing greenhouse gas emissions.

The article, “Global and regional climate changes due to black carbon,” is posted in today’s online version of “Nature Geoscience.”

Professor V. Ramanathan explains his new
findings to reporters. (Photo
courtesy UC San Diego)

“Observationally based studies such as ours are converging on the same large magnitude of black carbon heating as modeling studies from Stanford, Caltech and NASA,” said Ramanathan.

“We now have to examine if black carbon is also having a large role in the retreat of arctic sea ice and Himalayan glaciers as suggested by recent studies,” he said.

In the paper, Ramanathan and Carmichael integrated observed data from satellites, aircraft and surface instruments about the warming effect of black carbon and found that its warming effect in the atmosphere, is about 0.9 watts per meter squared.

That compares to estimates of between 0.2 watts per meter squared and 0.4 watts per meter squared that were agreed upon as a consensus estimate in a report released last year by the Intergovernmental Panel on Climate Change, a United Nations sponsored agency that periodically synthesizes the body of climate change research.

Ramanathan and Carmichael said the lower, more conservative estimates are based on widely used computer model simulations that do not take into account the amplification of black carbon’s warming effect when mixed with other aerosols such as sulfates.

The models also do not adequately represent the full range of altitudes at which the warming effect occurs, they said.

The most recent observations have found significant black carbon warming effects at altitudes in the range of 6,500 feet, levels at which black carbon particles absorb not only sunlight but also solar energy reflected by clouds at lower altitudes.

Between 25 and 35 percent of black carbon in the global atmosphere comes from China and India, emitted from the burning of wood and cow dung in household cooking and through the use of coal to heat homes.

Countries in Europe and elsewhere that rely heavily on diesel fuel for transportation also contribute large amounts.

“Per capita emissions of black carbon from the United States and some European countries are still comparable to those from south Asia and east Asia,” Ramanathan said.

Black carbon rises from land clearing fires on the island of Borneo. October 2006. (NASA image by Jeff Schmaltz, MODIS Rapid Response Team)

In south Asia, air pollution often forms a brownish haze. Ramanathan’s previous research has indicated that the warming effects of this smog appear to be accelerating the melt of Himalayan glaciers that provide billions of people throughout Asia with drinking water.

In addition, the inhalation of smoke during indoor cooking has been linked to the deaths of an estimated 400,000 women and children in south and east Asia.

Ramanathan said that an observation program for which he is currently seeking corporate sponsorship could dramatically illustrate the benefits. Known as Project Surya, the proposed venture would provide some 20,000 rural Indian households with smoke-free cookers and equipped to transmit data. At the same time, a team of researchers led by Ramanathan would observe air pollution levels in the region to measure the effect of the cookers.

Carmichael said he hopes that the paper’s presentation of the immediacy of the benefits will make it easier to generate political and regulatory momentum toward reduction of black carbon emissions.

“It offers a chance to get better traction for implementing strategies for reducing black carbon,” he said.

The National Science Foundation, the National Oceanic and Atmospheric Administration and the National Aeronautics and Space Administration funded the review.

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