Angeles, CA - The California Science Center
has announced the selection of Irving L. Weissman,
MD, as the 2002 California Scientist of the Year.
Dr. Weissman, professor of pathology and cancer
biology at Stanford University, is credited with
being among the first to isolate the hematopoietic
stem cell in both mouse and man. His groundbreaking
research has paved the way for dozens of experiments
that explore the cell's power to fight illnesses
as diverse as cancer and Parkinson's disease.
California Science Center established the California
Scientist of the Year Award in recognition of the
prominent role California plays in the areas of
scientific and technological development. A blue-ribbon
panel selects a nominee whose work is current and
advances the boundaries of any field of science.
Of those selected, eleven have earned the California
Scientist of the Year honors before becoming Nobel
interest in lymphocytes, the disease-fighting white
blood cells of the immune system, led him to explore
how they go awry to produce lymphomas such as Hodgkin's.
His work came to focus on the two types of lymphocytes
- T cells and B cells. He knew it would be important
to learn where these cells came from, so he began
searching for a common ancestor.
1988 after years of research, Weissman and his colleagues
devised a process of elimination to isolate the
blood-forming stem cell from a pool of bone marrow
was accomplished by building up as many blood-cell
binding antibodies as possible and using the antibodies
to select out non-stem cells. When an antibody attached
to a cell, that cell was eliminated from the group.
Finally, two antibodies known from previous research
to bind to stem cells were added to the small group
that remained. The few cells left in the pool were
tested to see if they were really stem cells by
injecting them into mice whose blood systems had
been destroyed by lethal radiation. The researchers
found that as few as 30 of these cells saved half
of the mice, renewing these survivor's entire blood
next challenge was to identify the stem cell in
humans. Since humans could not be subjected to the
same types of experiments as mice, Weissman and
his research team set out to make mice more like
humans. They created a special mouse, known as Hu-SCID,
that had all the components of the human immune
April 1992, Weissman and his collaborators reported
in the Proceedings of the National Academy of Sciences
that they had found a candidate for the human blood-forming
stem cell. In 1996, Weissman and his colleagues
at StemCells, Inc. a company he help found, initiated
several clinical trials using the newly discovered
stem cells in patients with various forms of cancer.
One trial involved women with late stage breast
cancer that had spread throughout their bodies.
The study addressed a problem observed in many cancer
patients treated with bone marrow transplants that
relied on the patient's own tissues for transplant
material: Tumor cells remained in the blood. In
the trial, the researchers extracted bone-marrow
material from the women, purified the stem cells
and reinfused them back into the patients after
they had been given chemotherapy. The purified stem
cells were tested after treatment and no residual
cancer cells were found. Results of the study were
published in December 2000 in Biology of Blood and
was described in statements supporting his nomination
as being "treasured throughout the world for
his love of life and science, his wonderful capacity
to communicate ideas and the excitement of science"
and that "there is no predicting what he might
accomplish but it will surely be pathfinding."
to Editors: The California Science Center
is located at 700 State Drive, in historic Exposition
Park, Los Angeles. Open daily from 10 a.m. to 5
p.m., except for Christmas, Thanksgiving and New
Year's Day. Admission to the exhibits is free. IMAX
ticket prices vary from $4.25 to $7.00. Phone (213)
744-2019 for advance ticket purchase or group discounts.
Both the Science Center and IMAX Theater are wheelchair
accessible. Parking is $6 per car - enter the visitor
lot at 39th and Figueroa Street. For general information,
including directions, phone (213) 744-7400 or visit
our website at www.casciencectr.org.