Developments to Watch
Edited by Catherine Arnst
Tracing the Cause of Schizophrenia
Scientists have long been aware that schizophrenia can run in families. But they do not know what triggers this devastating neurological disorder. Epidemiological studies have pointed to prenatal infections, household crowding, and urban upbringing as possible co-factors. Now, a new study reveals that an "endogenous," noncommunicable retrovirus similar to one that causes multiple sclerosis could be the culprit in some 30% of cases.
Retroviruses integrate into the host's DNA, making them exceedingly hard to destroy. AIDS is caused by a retrovirus, and some cancers may be triggered by them. But the human genome also contains endogenous retroviruses that wormed their way into our genetic makeup millions of years ago. Although usually benign, endogenous retroviruses can be activated by a genetic trigger or environmental factors, and have been associated with several chronic diseases.
The research team, led by Dr. Robert H. Yolken, examined the postmortem brain tissue of 35 patients with schizophrenia, 22 with other neurological disorders, and 30 with no neurological or psychiatric diseases. They found evidence of the HERV-W family of retroviruses in 10 schizophrenics, but none in patients without the disease.
The scientists are intrigued by the retrovirus' similarity to one associated with MS. Although the two diseases are very different, Yolken notes that both usually start in early adulthood, and there are cases of patients that have developed both. He suggests that the retrovirus may cause different diseases in different individuals, depending on the genetic trigger.
For Radioactive Metals, a Way to Keep Cool
Scientists at Los Alamos National Laboratory may have a safer way to sequester the 40-plus tons of surplus plutonium now sitting in U.S. storehouses. This radioactive metal is notoriously hazardous: Plutonium powder, for example, ignites on contact with air and dissolves in water. Combining plutonium with boron produces a substance that is more stable and less fissionable, but it requires melting them together at 3,000C, grinding them into powder, and then repeating the process again and again. This is far too inefficient to deal with plutonium by the ton.
Chemists Kent D. Abney and Anthony J. Lupinetti have created a boride compound from radioactive materials without the arduous grinding and at a relatively cool 400C to 800C. Their secret: Before blending the boron and uranium, which is safer to handle but behaves like plutonium, they produced compounds that combine readily. For example, uranium tetrachloride and magnesium diboride yield uranium boride plus magnesium chloride, which washes away easily. The chemists are now testing the process with plutonium.
By Mitch Nelin
Who's to Blame for Warmer Oceans
The evidence is mounting that human activity--and not some fluke of the global weather cycle--is causing the earth's oceans to heat up. Two studies in the Apr. 13 issue of Science report that greenhouse gas emissions have caused the oceans to warm over the past 50 years, based on correlations between actual water temperatures and computerized climate models.
Scientists know that the Atlantic, Pacific, and Indian oceans have warmed significantly since 1955, but there is some debate as to what might be causing the rise. Researchers at the University of California at San Diego took data for the past 50 years from an Energy Dept. climate model developed to help determine the impact of greenhouse gases on ocean temperatures and correlated the data with direct measurements of heat changes in oceans over the same period. The temperature rises predicted by the model were remarkably similar to actual ocean temperatures. A separate team from the National Oceanic & Atmospheric Administration (NOAA), using a different model, got the same results.
A Fat Source of Brand-New Tissue
Liposuction may soon yield something besides slim bodies for patients and fat fees for surgeons. In the April issue of the journal Tissue Engineering, doctors at the University of California at Los Angeles and the University of Pittsburgh reported that they had harvested versatile stem cells from fat obtained during liposuction.
Because stem cells have the ability to develop into muscle, bone, cartilege, and other types of cells, they are the building blocks of new medical procedures to repair tissue or construct artificial organs. Today, such cells are collected with difficulty from bone marrow--or, controversially, from fetuses. Unwanted fat deposits could provide a bountiful and uncontroversial source.
Other labs are making strides in the burgeoning field of tissue engineering. At the State University of New York at Buffalo and Shriners Burns Hospital-Boston, scientists have developed an artificial skin--based on real skin cells--that will release chemical compounds to promote wound healing, and could save the lives of burn victims. And researchers at Pacific Northwest National Laboratory are working on a polymer gel that holds live cells. Such gels may be injected into patients to deliver new cells or therapeutic proteins.
By Neil Gross
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Copyright 2001 , by The McGraw-Hill Companies Inc. All rights reserved.
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