| April
9, 2004
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DNA
Research Highlights Prostate Cancer Mechanisms
 |
The
number and intensity of the dash-shaped marks in the
lower right corner of these DNA
profile patterns indicates that normal cells (top) are
more active in removing damaged DNA than two different
lines of prostate cancer cells (center and bottom).
|
Certain
prostate cancer cell lines are unable to repair DNA damage
caused
by "free radicals," according to scientists at the
National Institute of Standards and Technology (NIST) and
National Institutes
of Health (NIH). This type of damage has been implicated before
in the development of prostate cancer, but the new research,
described in the March 25 online edition of Carcinogenesis,
provides the first solid evidence that the normal repair process
is altered in prostate cancer cells, possibly leading to
a cascade of events that culminate in further DNA damage and
cellular dysfunction.
Free radicals—highly
reactive molecules generated by both normal metabolism and
external
sources such as chemicals and ionizing radiation—produce
more than 30 different types of lesions in the nitrogen-containing
compounds or "bases" of DNA. The damage is generally
repaired in normal cells of young, healthy people. The NIH/NIST
study examined four types of lesions in DNA from both cell
nuclei and mitochondria, the energy factories of cells. The
scientists
found that prostate cancer cells unexposed to ionizing radiation
had
high levels of free radical damage and defective repair mechanisms.
They also found that, after exposure to ionizing radiation
and a
repair period, prostate cancer cells exhibited elevated
levels of
free radical damage and reduced removal of lesions.
Prostate
cancer is the most common form of cancer among American men.
The new findings may help to explain the molecular mechanisms
underlying the disease and support the idea that free radical
damage and repair are "critical factors" in its development.
The findings also have implications for possible therapies,
supporting the theory, for instance, that selenium—a trace
element that is a constituent of antioxidant enzymes—may
be useful in preventing prostate cancer.
NIST's
primary role in the study was to measure the types and levels
of DNA damage. NIST pioneered the development of methods for
detecting and measuring free radical damage at levels less than
one base per million bases. The research was led by the National
Institute on Aging.
Media
Contact:
Laura
Ost, (301) 975-4034
Controlling
Biomolecules With Magnetic 'Tweezers'
 |
© Geoffrey
Wheeler
NIST
post doctoral researcher Elizabeth Mirowski inserts a
magnetic tip into a holder for a magnetic force microscope.
The tip will be used to manipulate magnetic microparticles
attached to biomolecules as part of a project to study
folding patterns and other biochemical details. |
An
array of magnetic traps designed for manipulating individual
biomolecules and measuring the ultrasmall forces that affect
their behavior has been demonstrated by scientists at the National
Institute of Standards and Technology (NIST).
Described
in a recent issue of Applied Physics Letters, the
chip-scale, microfluidic device works in conjunction with
a magnetic force
microscope. It’s intended to serve as magnetic “tweezers”
that can stretch, twist and uncoil individual biomolecules
such as strands of DNA. The device should help scientists
study
folding patterns and other biochemical details important in
medical, forensic and other research areas.
The new
NIST device works like drawing toys that use a magnetized
stylus
to pick up and drag magnetic particles. Magnetic particles
2 to 3 micrometers across are suspended in a fluid and injected
into
the device. The surface of a thin membrane enclosing the fluid
is dotted with an array of thin film pads made of a nickel-iron
alloy. When a magnetic field is applied, each particle is attracted
to the closest nickel-iron “trap.”
So far,
the research team has demonstrated that the traps attract
individual
particles and that the microscope tip can gently drag particles
with piconewton forces. (One piconewton is about a trillionth
the force required to hold an apple against Earth’s gravity.)
The next step is to attach particles to both ends of biomolecules
such as DNA. The trapping stations then can be used to hold
one end of a molecule while the microscope tip gently pulls
on the other end. By applying magnetic fields in different
directions,
the researchers hope to ultimately rotate the magnetic particles
to produce complex single molecule motions for genomic studies.
Media
Contact:
Patricia
Russo Schassburger, (303) 497-3246 (Boulder)
New
Tool Helps Builders Evaluate Terrorist Threat
Today,
building owners and managers must respond to terrorist threats
that were once unimaginable. At the same time, budget constraints
make it critical that building design, location, construction,
management and renovation decisions be financially responsible.
Economists at the National Institute of Standards and Technology
(NIST) have developed a risk evaluation and mitigation process
that makes such security, safety and financial decisions easier.
The
three-step process, developed by NIST’s Office of Applied
Economics, helps decision-makers determine the vulnerability
of
their facility to damages from low-probability, high-consequence
events. The economic tool also identifies engineering, management
and financial strategies for abating the risk of damages. And
finally it uses standardized economic evaluation methods
to select
the most cost-effective combination of risk mitigation strategies
to protect the facility.
The
risk reduction strategies considered include (1) engineering
alternatives
(such as sensors to detect airborne contaminants or a reinforced
building shell); (2) management practices (such as evacuation
drills, security identity checks, improved communication with
first responders); and (3) financial mechanisms (such as government
subsidies or tax write-offs for capital improvements, reduced
insurance costs and increased rental rates due to new safety
features).
Software
that supports the economic evaluation of risk reduction strategies
is planned for this fall.
The
NIST risk evaluation and mitigation plan is found in “Cost-Effective
Responses to Terrorist Risks in Constructed Facilities”
by Robert E. Chapman and Chi J. Leng at www.bfrl.nist.gov/oae/oae.html.
Further information also is available in “Applications
of Life-Cycle Cost Analysis to Homeland Security Issues in Constructed
Facilities: A Case Study,” by Robert E. Chapman at the
same Web address.
Media
Contact:
John
Blair, (301) 975-4261
Glowing
Microspheres Improve Fluorescence Measurements
Laboratories
that measure emissions from fluorescent particles in a
wide
range of applications from clinical chemistry to biodefense
research to pharmaceutical development now can have more
confidence in their results thanks to new theory, standards
and methods
developed by the National Institute of Standards and Technology
(NIST).
The culmination
of five years of research, NIST's newest reference material
(RM 8640) is a set of calibrated microspheres coated with
fluorescent
dye. The tiny spheres, each one about one-tenth the width of
a human hair, are used to calibrate flow cytometry instruments
that measure fluorescence intensity.
Fluorescent
markers often are used to "tag" antibodies, cancer
cells, specific genes or other biomolecules. For example,
the
brightness of the signal from a sample can indicate whether
a disease is getting worse or is in remission. Until now, the
intensity of the signal, reflecting numbers of target molecules,
has been
judged visually or with benchmarks developed by individual
manufacturers. Previous research has shown that measurements
of the same samples
can vary by more than 100 percent depending on the instrument
used and a variety of experimental conditions.
The new
reference material, combined with previously developed NIST
standards and measurement procedures, now will provide an
authoritative national fluorescence measurement scale. Each
kit contains
six
vials of microspheres that emit fluorescent light at six different
intensity levels from zero to very bright. A flow cytometer
is used to analyze the contents of all the vials and an unknown
sample. By calibrating the cytometer to match the intensity
values provided by NIST for the reference vials, the intensity
of the unknown sample can be measured more accurately.
NIST's
work has been supported in part by the Centers for Disease Control
and Prevention, with supplies provided by the Food and Drug
Administration, Becton Dickinson Biosciences, Molecular Probes,
Inc., and Bangs Laboratory.
Media
Contact:
Laura
Ost, (301) 975-4034
New
Database Aids Medical Device Exporters
A
new international database has been released that
identifies measurement
procedures and materials that will help U.S. makers
of in vitro diagnostic (IVD) medical devices ensure
that their
products comply with European Union requirements. Staff
from the National Institute of Standards and Technology
(NIST) played a key role in the establishment and leadership
of the international committee that produced the
database.
Use
of the standards identified in the database should
facilitate worldwide comparability of clinical measurements,
which, in turn, should improve patient care, reduce
technical barriers to trade and reduce costs for
both IVD manufacturers and medical testing in general.
The European
Union recently issued new regulations on the sale of
in-vitro diagnostic (IVD) medical devices such as those
used to measure blood levels of glucose and cholesterol.
The EU "Directive" requires that values assigned
to commercial standards used for calibrating such devices
be traceable to appropriate "higher order"
measurement procedures and/or certified reference materials,
such as those from internationally recognized national
metrology institutes like NIST.
To assist
the U.S. IVD industry, which has more than 60 percent
of the European market, NIST provided leadership for
the international working group charged with selecting
the list of procedures and materials that can be used
to demonstrate compliance with the EU Directive and
with similar requirements that might be imposed by other
regions.
The
new database contains approximately 100 Reference
Measurement
Procedures, including 30 developed and maintained by
NIST. The database lists 96 approved reference
materials; NIST is the source for 72 of these.
For more information, see www.cstl.nist.gov/nist839/jctlm.htm.
Media
Contact:
Laura Ost,
(301) 975-4034
Ceramics
Data Enter a New Phase
It's
an anthology that is likely to be very popular with
designers
and manufacturers of ceramics and related materials worldwide.
The National Institute of Standards
and Technology (NIST) and the American Ceramic Society
(ACerS) have compiled, into a single compact disk,
nearly 20,000 phase-equilibria diagrams for more
than 15,000
chemical systems. Each diagram is akin to a ceramics
"road map" for a particular mixture of compounds—a
graphical representation of how chemical composition
and structure vary with changes in temperature, pressure
or other conditions. Covered materials range from
those
that superconduct to those that vibrate, resonate
or withstand inferno-like temperatures.
The collection contains all 20 volumes
of critically evaluated phase diagrams that the
ACerS-NIST
collaboration has published since 1964. As important,
the new CD-ROM features a variety of enhancements
to
improve search capabilities, ease of use and options
for manipulating, presenting and analyzing data.
Each
phase diagram is accompanied by a brief scientist-written
commentary that summarizes the source of the information,
methods of data collection and key facets of the diagram.
Accurate, reliable phase diagrams
reduce the potential for design and processing errors,
and
they may point the way to new types of materials with
superior properties. The ACerS-NIST program also
saves
research time and money by sparing individual scientists
and organizations from the necessity of gathering
the
data themselves, usually from disparate sources, and
evaluating its reliability. A 1997 assessment of
the
program estimated that each $1 spent on data collection,
evaluation and publication in this program produced
$10 in benefits to the R&D community.
For details on ACerS-NIST Phase Equilibria
Diagrams CD-ROM Database Version 3.0, see www.nist.gov/srd/nist31.htm or www.ceramics.org/phasecd.
Media
Contact:
Mark Bello,
(301) 975-3776
Quick
Links
Four
New Members Named to NIST’s Technology Advisory Committee
National
Institute of Standards and Technology (NIST) Acting Director
Hratch Semerjian has named four distinguished industry
and business experts to serve on the Visiting Committee
on Advanced Technology, the agency's primary private-sector
policy advisor. The new VCAT members are: Donald B. Keck,
Corning, N.Y., chief technology officer, Infotonics Technology
Center, Inc.; Edward J. Noha, Chicago, Ill., chairman
emeritus,
CNA Financial Corp.; Thomas A. Saponas, Colorado
Springs, Colo., retired senior vice president and chief
technology
officer, Agilent Technologies; and James W. Serum, West
Chester, Pa., president, SciTek Ventures. For more
information,
see www.nist.gov/public_affairs/releases/newvcat.htm
Simplifying U.S./Canada Trade of Telecom Equipment
U.S.
makers of telecommunication equipment now can certify
their products in the United States and ship directly
to Canadian markets, thanks to the latest step in carrying
out a 1998 trade agreement. This streamlining of the
regulatory approval process results from the Canadian
government’s recent recognition of seven U.S.
testing and inspection organizations that had been
recommended
as “certification bodies” by the National
Institute of Standards and Technology (NIST). Two-way
trade of telecommunications equipment between the two
neighbors totals about $7 billion a year. For more
information, see
www.nist.gov/public_affairs/releases/apec.htm.
(Return
to NIST News Page)
Editor:
Gail Porter
Date
created: 04/08/04
Date updated: 04/09/04
Contact: inquiries@nist.gov
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