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Stories of modern science ... from UPI

Aug. 15, 2002 at 8:00 AM   |   Comments

BRAIN CHEMICAL LINKED TO SCHIZOPHRENIA

Researchers at the University of California at Irvine and Rockefeller University have found a brain chemical that appears in reduced levels in victims of schizophrenia, a severe brain disease that often leads to hallucinations and "hearing voices." When researchers studied the brains of 14 deceased schizophrenia victims, they found reduced levels of a signal processor called DARPP-32 in an area called the dorso-lateral pre-frontal cortex, which is associated with schizophrenia. Researchers also found normal levels of DARPP-32 in brains of people who did not have the disease. DARPP-32 is the target of increasing scientific study. The neuro-transmitters dopamine, glutamate and serotonin; the anti-depressant Prozac; nicotine and even drugs of abuse such as cocaine and opiates all seem to work on the brain through the actions of DARPP-32. "This is the first study to show reduced levels of this important regulatory molecule in schizophrenia," researchers said. The finding could lead to therapy to restore normal levels of the chemical.


ALLOY COULD MAKE ARTIFICIAL MUSCLES

University of Florida researchers are studying the alloy nitinol to see if it can be used to manufacture prosthetic limbs. Nitinol -- a combination of nickel and titanium -- is used to make surgical stents that keep blood vessels from clogging. The alloy has a property called shape memory -- stents have a compressed shape when cool to make them easier to implant, but they expand to the right size and shape when warmed by body heat. So far, the alloy has been used only for small-scale medical and consumer products. Now researchers have used nitinol to build a device that can move more than 100 pounds, and researchers said they hope someday to build a nitinol "muscle" that can mimic the strength and motion of the real thing. "Basically, it's almost the size of a tendon or other large muscle," researchers said. "It requires a lot of electricity, but it does not require the kind of bulky motors or hydraulic pumps that drive similar devices."


USING ALFALFA TO HARVEST GOLD?

Ordinary alfalfa plants could be used as miniature gold factories to provide the nano-technology industry with a continuous harvest of gold nano-particles for use in microscopic electronic circuits and devices. An international research team is using alfalfa's natural ability to collect metals from soil to extract gold and store it in the form of nano-particles less than a billionth of a meter across. The alfalfa plants were germinated and grown in an artificial, gold-rich soil. Analysis by electron microscope confirmed the existence of gold nano-particles in the roots and along the entire shoot of the alfalfa plants. "'The work has demonstrated that using alfalfa is a cost effective and environmentally friendly method of producing gold nano-particles," researchers said. The next step will be developing techniques to extract the nano-particles from the plants.


PROBING CELLULAR STRESS MANAGEMENT

Penn State University researchers have shed new light on a stress-protection mechanism shared by both humans and plants and regulated by the molecular machinery in their cells. Researchers attached a green fluorescent tag to abscisic acid, or ABA, a protein associated with stress response. When they added the tagged ABA to plant cells, the protein quickly gathered together into speckles inside the cell nuclei that looked like green-glowing islands. The researchers then tracked the ABA as it began a complex molecular cascade that led to the closing of microscopic pores in the leaves to protect against loss of moisture. The same speckle effect by ABA in human cell nuclei is associated with stress-related remodeling of RNA. "A human autoimmune disease and a disorder associated with breast cancer are known to result from a defect in this process," researchers said. In agriculture, the finding could lead, for example, to new strains of corn that can maintain just the right moisture content.


(Editors: For more information on DARPP-32, contact Andrew Porterfield at 949-824-3969 or amporter@uci.edu. For NITINOL, Jose Santiago at 352-392-9461 or jrsan@ufl.edu. For NANO-PARTICLES, Neil Calder at 650-926-5133 or neil.calder@slac.stanford.edu. For ABA, Barbara K. Kennedy at 814-863-4682 or science@psu.edu)

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