Focus on Research
Penn State Intercom......October 4, 2001

Vitamin A plays role
in body's defenses

By Barbara Hale
Public Information

Experiments with human cells conducted by researchers have shed new light on vitamin A's role in the immune response, suggesting that the vitamin's active form may enhance the effectiveness of interferon, one of the body's natural defense chemicals and an immune system regulator. RESEARCH_Ross_Catherine

Catharine Ross, who holds the Dorothy Foehr Huck chair in nutrition in the College of Health and Human Development, led the research effort.

"There are quite a few animal studies that show that vitamin A deficiency affects inflammation and the immune system's response," she said. "These new data from experiments with human cells suggest that vitamin A augments natural interferon's regulatory response. Less interferon may be necessary when the active form of vitamin A is adequate."

In autoimmune diseases, the victim's immune system overreacts and attacks the body. For example, in multiple sclerosis, the immune system attacks the brain and spinal cord. In arthritis, the joints are attacked and in inflammatory bowel disease, the gut is the target.

Modified forms of interferon are currently being used to treat various autoimmune diseases such as multiple sclerosis, arthritis, inflammatory bowel disease or chronic inflammation. Ross speculated that the new data suggest that maintaining a person's normal levels of vitamin A may enhance the effectiveness of the form of interferon that is already in use as a medicine.

Qiuyan Chen, research associate, and Yifan Ma, a graduate fellow, collaborated on the research with Ross.

In the experiments, human cells, called macrophages, that are the first step in antibody production as well as potent mediators in the inflammatory response, were stimulated under both vitamin A deficient and sufficient conditions.

Chen said, "The cells were deficient in vitamin A at the outset when we observed their response to inflammatory stimuli. Then, we gave them a normal physiological level of retinoic acid, the form in which vitamin A is active in the body, and observed an enhanced activity of the interferon."

The experiments also showed that the presence of retinoic acid can inhibit other known inflammatory and immune response mediators, including tumor necrosis factor.

Ross explained, "We're looking at these basic cellular processes in order to understand the mechanisms of productive immune responses and to try to find ways to control the pathologic responses. While these basic studies are not targeted at specific diseases, they do shed light on the underlying disease processes.

"Patients should continue to follow their personal physician's advice," she added. "Vitamin A is a potent drug as well as a nutrient."


Barbara Hale can be reached at .

Scientists detect what may be
universe's first powerful source of light

An international team of 28 scientists from the Sloan Digital Sky Survey, including two University astronomers, has found evidence that the most distant object yet detected may be one of the universe's first powerful sources of light, solving a mystery that had eluded scientists for nearly four decades -- when did light first start to break through the dark clouds that filled the early universe.

The object is a quasar, a type of galaxy that produces intensely luminous radiation from the violent destruction of some of its stars by its massive central black hole. This particular quasar is one of several very distant such objects whose discovery was announced in June by Donald Schneider, professor of astronomy and astrophysics, who has been chair of the Sloan Digital Sky Survey quasar science group since its inception in the early 1990s. Schneider, along with postdoctoral fellow Gordon Richards, is a coauthor of the recent mystery-solving analysis of the quasars' spectra from new, high-quality observations with the Keck telescope in Hawaii.

The most distant quasar yet discovered sits at the astronomical ZIP code known as "redshift 6.28," which is so far away that the object's light started on its journey toward Earth when the universe was only about 5 percent of its current age.

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Burning can clean up
many ocean oil spills

By Barbara Hale
Public Information

University researchers have shown in laboratory experiments that some open water oil spills previously thought to be incombustible potentially can be cleaned up via burning, the most efficient, rapid and environmentally friendly option.

Anil K. Kulkarni, professor of mechanical engineering, said, "Oil spill combustion can be a highly effective cleanup measure for contained spills occurring on open water bodies, such as an oil spill on the ocean contained by booms or a spill surrounded by ice. When feasible, it is an inexpensive technique that can have a very high efficiency of removal, possibly greater than 99 percent. The burning is very rapid and any resulting ecological damage is less severe compared to conventional oil removal methods."

However, the window of opportunity for using burning is often limited by wave and wind conditions and by the proximity of the spill to populated areas. In addition, over time, oil spilled at sea becomes mixed with water forming an emulsion that is difficult or impossible to ignite.

Now, University researchers have widened the applicability of burning by showing that diesel fuel emulsions up to 80 percent water and crude oil emulsions up to 35 percent water can be ignited. In laboratory experiments, they demonstrated that positioning an external radiant heat source near the spill facilitates ignition. In addition, they have developed simple charts for use as a quick reference to determine the minimum external heat source needed to facilitate burning.

Kulkarni points out, however, that an open water demonstration still needs to be done to show proof of concept.

The researcher detailed the findings in a paper at the Arctic and Marine Oil Spill Program meeting in Calgary, Canada. His co-author is A.Y. Walavalkar, who recently earned his doctorate at Penn State; part of the work was the subject of Walavalkar's doctoral dissertation.

Barbara Hale can be reached at