Mastectomies Significantly Lower Risk
of Breast Cancer
An
international study led by researchers from the Abramson
Cancer Center
has found that a prophylactic double mastectomy--surgical
removal of both breasts to prevent a cancer before it occurs--can
lower the risk of developing breast cancer by 90% in women
genetically pre-disposed to the disease. This is the first
study to quantify the risk reduction for this procedure
and its impact on hundreds of thousands of women in the
U.S. who carry mutations in one or both of the two genes--BRCA1
and BRCA2--strongly linked to breast and ovarian cancer. Their
findings will appear in the March 15 edition of the Journal
of Clinical Oncology.
"Women are still at risk for breast cancer
after any kind of mastectomy as some breast tissue remains
in the body after surgery," said lead author Dr. Timothy
R. Rebbeck, associate professor of epidemiology at the
School of Medicine and co-program leader of the Center's
Cancer Epidemiology and Risk Reduction Program. "Now that
we have quantified the benefit of a double mastectomy for
reducing the chances of breast cancer, women in this high-risk
group can make a better-informed decision about having
breast surgery in addition to other forms of prevention,
such as regular screening and/or other preventive surgeries,
including ovary removal."
The PROSE
study, (Prevention and Observation of Surgical Endpoints),
followed 483 at-risk women from
11 sites in the U.S., Canada, the U.K. and the Netherlands
for over six years. Most of the North American women chose
not to have preventive, or prophylactic, double mastectomies.
Women who chose to have prophylactic mastectomies were
paired with women in a control group based on type of mutation,
treatment center and year of birth within five years. In
addition, none of the participants had any previous or
current diagnosis of cancer upon entering the study.
Breast
cancer was diagnosed in two of 105 women (1.9%) who had
double mastectomies. The occurrence
of breast cancer was much greater in the control group,
with 184 of 378 women (48.7%) developing breast cancer.
Study results also confirmed a large risk
reduction for breast cancer (95%) for women who also had
their ovaries removed.
Funding
for this study was provided through a research grant
from the NIH, Penn's Abramson Cancer Center,
the Breast Cancer Research Foundation, the Dana-Farber
Women's Cancers Program, the US Department of Defense Breast
Cancer Research Program, the Utah Cancer Registry, the
Falk Medical Research Trust, the Utah State Department
of Health, and the Nebraska State Cancer and Smoking-Related
Diseases Research Program.
The
Body's 911 Call: Why Blood Flow
Stops Short
While it's common knowledge that high levels
of LDL, also known as "bad" cholesterol, can lead to the
restriction of blood vessels and a higher incidence of
heart attack, stroke and diabetes, the exact method of "how" has
remained a mystery. Now, researchers from Penn's School
of Medicine have discovered the exact mechanism to explain
why blood vessels are restricted in patients with cardiovascular
diseases, thus preventing blood flow and causing disease
symptoms. These finds were published in the February issue
of Nature Structural and Molecular Biology.
"We all have oxygen-heavy toxins in our
bodies," said Dr. Xiang Dong Tang, staff scientist in physiology. "When
there are high levels of LDL or sugars in the blood, those
toxins are generated in excess, and the body can't break
them down as efficiently as a healthy body can. This kicks
off a chain reaction that leaves blood vessels contracted.
Now we know how that chain works, down to the amino acid
residue that is targeted."
That amino
acid is Cysteine at position 911 of a protein called
the Maxi-K potassium channel, which
is typically made of approximately 1,200 amino acids. The
Maxi-K channel moves potassium ions out of blood vessel
muscles and serves as a critical regulator for blood vessel
tone. It works in one of two ways: either from an electric
shock or an increase in calcium within the channel. When
Cysteine911 is altered by an oxygen-heavy toxin, calcium
doesn't enter the Maxi-K channel. If the Maxi-K channel
is inhibited, then the vascular muscle isn't told to relax,
thus restricting blood flow.
"We also found that the Maxi-K channel
isn't permanently damaged when Cysteine911 is altered," said
Dr. Toshinori Hoshi, associate professor of physiology
and co-author of the article. "In fact, with the
right chemical agent, it can be reversed." In initial
laboratory tests, the researchers have found that a chemical,
NS1619, can allow the damaged Maxi-K channel to continue
to function. "This discovery could lead to the production
of drugs that would reverse the negative effects on the
Maxi-K channel. It would be an alternative method for treating
cardiovascular diseases and even diseases relating to aging," said
Dr. Hoshi.
Scientists
also contributing to this research include Marcia L.
Garcia from Merck Research Institution
and Stefan H. Heinemann from Friedrich Schiller University.
This research is funded by the NIH.
Cache of Seal Impressions Discovered
in Western India
Excavating at the ancient town of
Gilund in southern Rajasthan, India, one of the largest
sites of the little-known Ahar-Banas culture, archaeologists
led by teams from the University of Pennsylvania Museum
and Deccan College, Pune, India have discovered a bin filled
with more than 100 seal impressions dating to 2100-1700
B.C. The existence of the seals, and their particular styles,
offer surprising new evidence for the apparent complexity
of this non-literate, late and post-Indus Civilization-era
culture, according to Dr. Gregory Possehl, curator-in-charge
of UPM's Asian Section and excavation co-director. Dr.
Possehl's collaborator, Dr. Vasant Shinde of Deccan College,
and their teams made-up of professionals and students from
around the world, have conducted excavations at Gilund
over four seasons, beginning in 1999. The team is working
to understand the social life, history and agricultural
developments of these peoples, separated by about 200 miles
of largely mountainous and desert-like regions from the
powerful Indus Civilization that had its heyday 2500-1900
B.C. They came upon the bin with its seal impressions in
the 2002-2003 season completed in February.
Clay,
nature's soft and plentiful
sealant, has been used by people for millennia to keep
containers closed. Seals, on the other hand, frequently
decorated with symbols to indicate a person or persons
and used to make seal impressions that lay claim or suggest
special rights to a container's contents, suggest a more
stratified society. While no actual seals were discovered
at Gilund, the unexpected collection of so many seal impressions
strongly points to the presence of a populate of elite
citizens who used stamps as identification of themselves
and their elevated status--and who marked commodities that
were stored in this building under their control. A large
oval shaped bin about 5 feet deep and 2.5 feet in diameter
at its midpoint, to keep the seal impressions in--and potentially
keep others from duplicating specific impressions for their
own use--further indicates the elitist nature of this warehouse.
The impression designs according to Dr.
Possehl, offer additional evidence for a more worldly-wise
culture than was formerly assumed to exist at Gilund. The
impressions found in the bin were made from seals both
round and rectilinear. The design motifs are generally
quite simple, with wide-ranging parallels from Indus Civilization
sites such as Chanhu-daro, Pirak, Kot Diji and Nindowari,
400 to 500 miles away. There are also distinct parallels
with seals from another cultural group archaeologists call
the Bactria-Margiana Archaeological Complex (BMAC), from
as far away as Central Asia and northern Afghanistan, 1,000
miles to the northwest.
"Gilund is providing us with good evidence
for a stratified society that had wide-ranging contacts
between the peoples of western India, Pakistan, Afghanistan
and Central Asia just at the end of the third millennium
and the beginning of the second millennium," noted Dr.
Possehl.
Generation Gap Explains Decline in Feminist
Ranks
Despite
gains brought about by the women's
movement, young adults are far less likely than their middle-aged
counterparts to call themselves feminists, according to
a study conducted by Dr. Jason Schnittker, assistant professor
of sociology at Penn, Dr. Jeremy Freese, assistant professor
of sociology at the University of Wisconsin-Madison, and
Dr. Brian Powell, professor of sociology at Indiana University.
Researchers
examining the link between age and social attitudes about
feminism found that support
for abortion rights and gender equality in the workplace--a
strong part of the feminist tradition--is virtually unrelated
to whether young adults as well as senior citizens call
themselves feminists.
"These results suggest that men and women
whose political coming of age coincided with the feminist
movement are more likely to think of themselves as feminists
than their younger or older counterparts," said Dr. Schnittker,
co-author of the report, Who Are Feminists and What
Do They Believe: The Role of Generations. The report
was published in the American Sociological Review.
Dr. Schnittker
said that, while the feminist movement may not lose any
of its hard-won accomplishments,
the findings indicate that it may be increasingly difficult
for contemporary feminists to present the united front
once characteristic of feminism.
"There appear to be many more conceptions
of feminism these days than there were in earlier generations,
allowing a variety of different people, with a variety
of different ideologies, to self-identify as feminists.
It's not just a story about some groups moving away from
feminism, which most people have assumed, but about new
groups and diverse ideological groups moving into it." The
study also found that: