A closer look

    A closer look

    A new electron microscope gives scientists a glimpse into the heart of childhood catastrophic disease.

    In the semi-darkness, Sharon Frase peers into what looks like a massive periscope. Computer screens spring to life as she literally gazes deep into the heart of a cancer cell to reveal its inner workings. “Here are the mitochondria,” she explains, pointing to the organelle that is the cell’s energy source. “This is the nucleus where all of the genetic information is stored.” It’s difficult to comprehend that these spectacular images originate in a nearly invisible speck of tissue that has been placed on a Lilliputian grid and tucked deep inside a transmission electron microscope.

    The instrument that created these images will help scientists at St. Jude Children’s Research Hospital better understand cancer and other diseases. Capable of magnifying an object 700,000 times, the hospital’s new electron microscope enables investigators to see things they could not see before.

    “This technology will allow us to get a better look at cancer and better understand how it grows and spreads and responds to therapy,” says Michael Dyer, PhD, Developmental Neurobiology. By comparing images derived from an electron microscope, Dyer and his colleagues have learned how the eye cancer retinoblastoma spreads. “Using the electron microscope, we learned how the cancer cells break away from the tumor and begin to spread throughout the body,” he says. “This may allow us to develop new therapies to stop retinoblastoma metastasis.”

    An electron microscope uses a beam of electrons to produce highly detailed images that reveal a specimen’s structure and composition. The new instrument, one of only 200 of its type in the world, is the centerpiece of a recent expansion of cellular imaging at St. Jude. Nearly twice as powerful as the hospital’s other electron microscope, the 200kV model offers many innovative features, such as the capacity to provide 3D views. “This scope is like nothing I have ever used in my 35 years of electron microscopy,” Frase explains. “It’s so sensitive that your voice can disrupt the images.”

    Preparing specimens for imaging is a tedious and time-consuming process that demands knowledge, patience and a steady hand. The lab’s technicians can provide the imaging service or can teach interested faculty, postdoctoral fellows and other scientists how to use the equipment.

    Frase, director of the electron microscopy center, pulls out a small block of epoxy resin, in which has been embedded what appears to be a fleck of pepper. “This is a piece of tumor,” she says. A technician uses a diamond knife to cut the specimen into whisper-thin slices, manipulating the sections with a brush consisting of a single hair. Sections are placed on tiny copper grids and stained with heavy metals before being loaded into the microscope.

    The new electron microscopy center is one more example of how the hospital constantly improves its research capabilities.

    St. Jude Scientific Director James Downing, MD, spearheaded the effort to expand the facility, an initiative that is sure to yield scientific discoveries that will save lives. “Our goal is to be the best in the world, Frase says. “St. Jude wants to have everything available that a researcher needs to find cures for devastating childhood illness. That’s the bottom line, and that’s what St. Jude has done by installing this facility. I feel fortunate to be a part of it.”

    Reprinted from Promise Spring 2008

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