News, 17-18/5/00 (2)
hyt...@my-deja.com
* Language-Testing Study Shows No Effect From Secretin For Children With
Autism
ScienceDaily, 18/5/00 - Sometimes wishing does not make it so.
Parents of autistic children began calling Melvin Heyman, MD, chief of
pediatric gastroenterology at the University of California, San Francisco
in 1998. They were full of hope about reports that secretin, a hormone
produced in the intestines and used in a diagnostic procedure, might
improve their children' s ability to talk and interact with others. To
test that concept, Heyman and clinical research fellow Jenifer Lightdale,
MD, teamed with autism experts from UCSF's Langley Porter Psychiatric
Institute to perform objective tests of language and behavior before and
after administering secretin.
The results were reported May 13, 2000 at the Pediatric Academic
Societies/American Academy of Pediatrics meeting in Boston. Twenty
autistic children, aged 3-6, received formal language testing before
infusion with secretin and in four follow-up tests in ensuing weeks. No
child showed significant changes in either receptive or expressive
language.
"Beginning in 1998, a worldwide storm of reports on the internet, plus
stories in the Wall Street Journal and on Dateline NBC, have described
secretin as potentially a true treatment for children with autism," said
Lightdale. "Our study and one other were the first to test objectively
whether this was so. We began the study because we were concerned that
parents and health care providers did not have sufficient scientific
information to evaluate secretin's potential effects."
Both studies had negative results. However, the researchers reported that
some parents from both study groups indicated they still would use the
drug for their children.
Lightdale conducted the UCSF study under Heyman's supervision. Their co-
investigators were UCSF-LPPI autism experts Bryna S. Siegel, PhD, Glen R.
Elliott, MD, PhD, Cathy Hayer, MA, and Christopher Lind-White, MD.
Lightdale is now a postdoctoral fellow in pediatric gastroenterology at
Children's Hospital Boston.
Heyman said that parents' excitement about secretin were first stirred by
1998 stories of a mother who said that her son showed improvements in
autistic symptoms after he was given secretin during a diagnostic test
for diarrhea. Dateline NBC profiled the mother and her son. The Wall
Street Journal described an entrepreneur, the father of two autistic
children, who founded a pharmaceutical company and obtained the license
for synthetic secretin to ensure a supply of the drug to treat autism. An
article in the Journal of the Association of Academic Minority Physicians
described the first boy, as well as two other children who reportedly
showed increased alertness, eye contact and expressive language within
days after receiving a single dose of the hormone. The article described
marked improvements in language over a short time, and reported effects
lasting up to five weeks.
"After word of these observations spread, UCSF's gastrointestinal service
was inundated with calls from parents asking for secretin infusions,
often as many as 30 per day," Heyman said. Eventually, more than 2,000
called from Northern California and around the country. "The need for
research to see whether the drug was effective was accentuated by reports
from autism interest groups that thousands of children had begun
receiving secretin in repeated doses," Heyman said. Some web
entrepreneurs charged inflated prices to give secretin to autistic
children. In some cases the drug was administered in unproven ways, such
as by mouth or through the skin using a solvent called DMSO.
Siegel, who is associate adjunct professor of psychiatry at UCSF, has
worked with autistic children and their families for 25 years. She
defined autism as a syndrome that begins in the first few years of life,
involving severe deficits in social and communication skills. It affects
the child's ability to process incoming information from the social and
physical worlds, to interact with others and to use language. The cause
is not known and, to date, there is no proven cure. However, for some
autistic children, behavioral interventions can markedly improve language
and social skills. For older individuals, medications sometimes can help
ease obsessive behaviors.
Heyman said that secretin is a hormone that stimulates the pancreas to
increase production of digestive fluids. It is approved as a diagnostic
drug, to show whether the pancreas is impaired in its ability to respond
to stimulation, since that can cause chronic diarrhea and other
disorders. Secretin has no known therapeutic use, and few known side
effects, though one version of the drug has been associated with allergic
and anaphylactic reactions. It has not been tested for safety or efficacy
in children, either in a single-dose or as a long-term medication.
Lightdale's study looked at autistic children who were near the same age
and were given a similar intravenous dose of secretin to the three
children described in the 1998 journal article. Each child in the UCSF
study was tested before the infusion with secretin and again in sessions
one, two, three and five weeks after infusion. Each child was given a
standardized test called the Preschool Language Scale - 3, and was
videotaped during play and scored for specific behaviors characteristic
of autism.
The PLS-3 test was objectively scored and indicated no quantifiable
changes either in the way children understood language, or the way they
were able to use words and gestures to express themselves. The videotaped
behavior tests were scored using criteria in the test manual, by three
independent reviewers who never met the children and were not told which
week of the study a given test represented. The latter results will be
published at a later date.
A true, dramatic change in skills and behavior would have been a
surprising result after a dose of a drug, said Siegel. "The claims made
for this drug do not hold up well to any neuro-developmental model of how
new skills are acquired," she said. "Language ability depends on changes
in the brain as the child goes through activities that stimulate the
acquisition of vocabulary and grammar structure. The child has to develop
a two year old's language ability to go on and learn to speak like a
three year old. A pill can't do that for him."
Eighteen sets of parents in the study filled out a survey afterwards
about their child's condition. In contrast to the results observed by the
study authors, 15 sets of parents indicated that they felt their child
had moderate to significant improvements in language skills following the
secretin infusion.
The UCSF results are similar to those of another study, reported in
December, 1999 in the New England Journal of Medicine, by researchers at
the University of North Carolina. They studied children aged 3 - 14 who
had either autism or a similar condition, pervasive developmental
disorder. They administered secretin to half and placebo to the rest. The
UNC researchers found no significant effect of secretin - in fact, the
children who received the placebo showed slightly greater improvement on
behavior tests. However, a majority of parents, including those whose
children received placebo, retained their interest in using secretin even
after they were told the results.
How to explain the difference between objective test scores and parents'
perceptions? "This is a very good example of placebo effect," said
Siegel. "By definition, the placebo can be expected to cure whatever ails
you. In the studies of secretin, these parents saw differences in eye
contact, in attention, in use of words - any activity that seemed like an
improvement was attributed to the drug."
"Hope is essential when you care for a child with a chronic disability
and there is no definitive treatment," Siegel said. "But sometimes hope
lets people believe more than they truly can count on. It can be a
roller-coaster that, in the end, is just another source of strain."
* Linux makes inroads into high-end computers
CNET News.com, 17/5/00 - Parallel actions by Hewlett-Packard, SGI and Red
Hat are combining to put major muscle into the development of Linux for
Intel's future flagship Itanium chip.
Next week, Hewlett-Packard and Intel are expected to release programming
tools that will enable people to create and run software designed for the
new chip, sources familiar with the companies' plans said. Though some of
these tools exist already, the key new feature will be an HP product that
lets people try out Itanium software without having to wait for one of
the relatively rare prototype machines.
Intel and HP representatives declined to comment on the plan.
Meanwhile, SGI--a maker of high-end computers that is banking much of its
future on Linux and Intel chips--released its own tools Monday to help
write software for Itanium computers. Members of the Trillian team
creating Linux for Itanium have been eagerly awaiting these critical
tools, called "compilers," which translate programming code into
instructions a computer chip can understand.
While HP has the most experience with the details of the IA-64
architecture, SGI is good with compiler expertise in other areas. "They
have had historically very good compilers, and they have very good
compiler people," said MicroDesign Resources analyst Keith Diefendorff
said.
The release of the HP emulation software will be accompanied by compilers
developed by Cygnus and supporting software called libraries from Intel.
Red Hat has caught up to rival TurboLinux by releasing its test version
of Linux for the Itanium chip. TurboLinux released its first version, a
very raw prototype, two months ago.
The moves are critical for Linux if it's going to meet the expectations
Intel and others have for the upstart operating system, still too new to
be suitable for most high-end applications. Consequently, Linux currently
is most popular in low-end servers based on 32-bit Intel chips, but
Itanium and its successors in Intel's "IA-64" family offer a path that
could lead Linux into higher-end computers.
But developing software for the new chip is difficult right now because
there are so few Itanium prototype computers to go around. Intel has
shipped more than 3,000 so far, but the systems are in high demand and
aren't available to the vast majority of Linux programmers.
The three announcements illustrate the cooperative nature of the Linux
movement: All the companies involved, as well as others, can take
advantage of the software its competitors are releasing. By comparison,
Microsoft and Sun are working separately to develop Itanium versions of
their own operating systems.
Linux, a clone of Unix developed by a host of "open-source" programmers
who share software, competes with Windows and versions of Unix from Sun
and others. To accommodate the Linux movement, Intel has had to curtail
its usually secretive methods, sharing more chip information than is
typical for an unreleased product.
The goal is that Itanium versions of Linux will be available at the same
time Itanium systems ship later this year. Linux dovetails with Intel's
philosophy of bringing high-end technology into mainstream computers.
Intel hopes the Itanium chip and its successors will bring Intel
technology into expensive, high-power computers that previously were the
domain of Sun, Compaq, IBM and SGI, each of which have 64-bit processors.
The Itanium chip, Intel's first 64-bit processor, will be able to manage
vastly larger databases than 32-bit chips and will be much faster at
mathematical calculations.
HP, the original inventor of the design underlying the IA-64 chips, has
its own compilers but has yet to release them. "In my talking to HP, my
feeling is they believe their value-add in this whole IA-64 proposition
is their compiler," Diefendorff said.
More surprising to Diefendorff was the fact that SGI chose to release its
compiler. Likely reasons for the move include an attempt to win the
attention, respect and goodwill of the Linux community and to foster
development of software that will run on the type of computers SGI is
good at building, such as its next-generation SN-1.
SGI released its compilers as open-source software under the General
Public License license, which allows other programmers--including SGI
competitors--to see how SGI achieved its reputation for strong compiler
abilities. In addition, the SGI compilers may legally be fused with
compilers from Red Hat's Cygnus team or modified by a user.
Microsoft is attached to the IA-64 architecture for some of the same
reasons as Linux companies are: a way to penetrate untapped high-end
markets. Microsoft's new Windows 2000 operating system is helping to undo
the company's reputation for crash-prone software, but at the same time,
the number of chips Windows runs on has dropped from four in the 1990s to
one today.
Intel favors three operating systems for IA-64 computers: Linux, Windows
and a version of Unix called Monterey-64 being jointly developed by IBM
and Santa Cruz Operation.
IBM has its own plans for using Linux in high-end machines. The company's
work developing Linux for its mainframe S/390 computers has now become an
actual product.
TurboLinux and SuSE, two of the four major sellers of Linux, will
distribute Linux for the S/390 in partnership with IBM's global services,
IBM said today. The new version will allow Linux software to be used on
these very expensive but very reliable servers, opening them to a wider
range of uses.
Sun, though its Solaris operating system is more mature than Linux, can
only dream of the attention Intel is lavishing on Linux. Intel and Sun
are feuding over how much support Intel will give Sun in developing
Solaris for IA-64. At the root of the disagreement is the fact that Sun
prefers to sell computers based on its own UltraSparc chips.
* Commentary: Market not ready for high-end Linux systems
CNET News.com, 17/5/00 - Gartner does not consider the Linux technology
or the market itself as mature enough for a significant run at the high
end.
High-end servers (as implemented on platforms from Sun Microsystems, IBM,
Hewlett-Packard, Compaq Computer, Unisys and others) have a high level of
functionality in what Gartner terms the "ities": scalability,
availability, manageability, security.
The "ities" represent significant investments by vendors over many years
and are the core differentiating factors in the competitive dynamics of
the market. Without strong vendor interest and enthusiasm to transfer
hard-earned technologies into the Linux market, these capabilities may
emerge only sporadically.
A particular point solution may exist here or there, but the overall big
picture of a complete and comprehensive vendor-supported environment will
be lacking.
Gartner believes that some vendor reluctance regarding Linux arises from
the nature of the open-source movement itself. If a viable market is to
develop in high-end Linux servers, strong independent software vendor
enthusiasm must be present. However, the big software developers are
already largely locked into specific platforms and require additional
resources or a need to substitute Linux for an existing one.
Many such developers fear lackluster profit returns in an untested
market. That inertia requires market momentum and a strong, sincere
commitment from the vendor community on behalf of Linux. However, the
vendor community is split in its allegiance. Those with a strong server
position are reluctant to jeopardize their products by offering lower-
cost alternatives unless the market is clearly differentiated and adds
opportunity to their business models.
Therefore, Linux has been relegated to more downstream applications in
server appliances or to low-end deployments in Web applications rather
than the high end.
This cycle of "wait and see" in the Linux market will require some major
forces to propel the operating system into the forefront of consideration
as a competitive and viable long-term alternative to the server platforms
in existence.
Enterprises will be reluctant to consider Linux without the full
framework of global service and support, breadth of applications, vendor
commitment, and a high level of "ity" functionality. A market change of
such magnitude usually requires several years of maturity and evolution.
Entire contents, Copyright © 2000 Gartner Group, Inc. All rights
reserved. The information contained herein represents Gartner's initial
commentary and analysis and has been obtained from sources believed to be
reliable. Positions taken are subject to change as more information
becomes available and further analysis is undertaken. Gartner disclaims
all warranties as to the accuracy, completeness or adequacy of the
information. Gartner shall have no liability for errors, omissions or
inadequacies in the information contained herein or for interpretations
thereof.
* RealNetworks adds Flash to audio-video software
CNET News.com, 17/5/00 - Continuing its push toward offering capabilities
normally associated with generic Web browsing, RealNetworks is adding Web
animation technology to its flagship RealSystem software.
RealNetworks plans to integrate Macromedia's Flash 4 animation software
into RealSystem, which transmits audio and video over the Web.
RealNetworks plans to pitch the souped-up RealSystem to companies with e-
commerce offerings.
"Consumers who currently shop directly from within the RealPlayer can now
take full advantage of interactive text and graphics," the companies said
in a statement. "The integration amounts to one of the world's richest
and most complete online shopping experiences."
The addition of Flash 4 is the latest move by RealNetworks to advance on
the territory of traditional browsers. It comes directly on the heels of
the company's creation of streaming media software with fairly advanced
Web page-viewing capabilities.
That product was created for a RealNetworks consulting client, Global
Media, and is not available for general use.
RealNetworks will demonstrate RealSystem's Flash integration at the Real
Conference 2000 in San Jose, Calif., next week.
* Wireless Net May Require "Smart Antennas"
WEST LAFAYETTE, Ind. (ScienceDaily, 18/5/00) – Just as people hear better
with two ears than with one, future wireless communications devices may
have two or more antennas so they can outperform conventional, single-
antenna versions.
These "smart antennas," when combined with sophisticated signal
processing techniques, may be especially critical in preventing Internet
traffic jams as an increasing number of people use wireless devices to
download files from the Web. The use of multiple antennas may enable a
new generation of cellular communications equipment to better access the
Internet and download large amounts of data, including video files, says
Michael Zoltowski, a professor in Purdue University's School of
Electrical and Computer Engineering.
Zoltowski will present a research paper about smart antennas on June 9 at
the International Conference on Acoustics, Speech and Signal Processing
in Istanbul, Turkey. The conference is sponsored by the Signal Processing
Society of the Institute of Electrical and Electronics Engineers.
In the United States, the number of people downloading data with wireless
devices is expected to surge from the current 3 percent of the online
population to 78 percent over the next year, according to Cap Gemini
America Inc., an information technology and management consulting
service.
The performance of wireless devices, such as cell phones and laptop
computers, is plagued by interference. But equipping future devices with
two or more antennas would drastically reduce the interference,
increasing reception accuracy by as much as 100 times and enabling three
times as many wireless users to operate within the same frequency band.
The antennas are referred to as smart because they are able to reject the
interference and compensate for the "multipath effects" caused by signals
reflecting off buildings and other structures, Zoltowski says.
"The problem will be when numerous users want to download from the Web
through wireless links at the same time," he says." The interference
created will choke the wireless Net connection."
Texas Instruments Inc., which is partially funding research at Purdue to
develop the technology, is testing a prototype cell phone that has two
antennas. The second antenna is a patch-like strip instead of the
standard whip antenna. A similar setup might also be used for laptop
computers.
"We want a user to be able to fire up the laptop and, while in a car or
on a train, with no wire connections, be able to download information
from the Web," Zoltowski says. "That's the goal of the next generation of
cellular communication systems."
Cellular communications depend on a series of "base stations" that
provide service to separate regions called cells, which are arranged in a
sort of honeycomb pattern spanning large geographical areas. The
performance of these systems is hindered by two types of interference
that foul up a widely used technique critical to the economical
functioning of cellular communications. That technique, called code
division multiple access – commonly referred to in the wireless business
as CDMA – makes it possible for many users to operate on the same
frequency band at the same time.
One type of interference is caused by the multipath effects that result
when signals bounce off buildings or mountains on their way to and from
cellular base stations. For CDMA systems to work without interference,
the signals for numerous users must be transmitted in a precise sequence
with exact timing. But delayed echoes of the signals are created when
they bounce off objects, fouling up this delicate sequence and causing
them to interfere with each other. It's a problem called "multi-user
access interference." Having more than one antenna would help correct the
problem.
The other type of interference in CDMA systems occurs while the user
approaches the boundary of two adjacent cells and has to be "handed off"
from one base station to the next.
"When I am at the edge of a cell, two base stations are talking to me
simultaneously," Zoltowski says. "While I am attempting to listen to one
of them, the other one is interfering. Having two antennas allows the
receiver to distinguish between the two base station signals because they
are arriving from different directions, in much the same way that having
two ears gives us the ability to determine from which direction sound is
coming."
The performance of wireless systems could be further improved by
switching from the conventional technology used to deal with multipath
effects, referred to as a "Rake receiver," to sophisticated techniques
that attempt to restore the delicate timing and sequence of the codes
that are used to transmit data. Using these techniques, called "space-
time equalization," and equipping devices with more than one antenna,
would increase the number of users able to operate simultaneously in each
frequency band.
Theoretically, CDMA should be able to accommodate up to 64 users in each
band.
"But the reality is, because of these kinds of interference effects, they
can only allow about 20 users in a given band, or, at most, a third of
the potential number," Zoltowski says.
Computer simulations have shown that using two antennas and space-time
equalization would enable the simultaneous use of all 64 channel codes in
each frequency band.
"Just for one user to download video files even close to real time
requires a large bandwidth for that user," Zoltowski says. "Given limited
spectrum allocation by the Federal Communications Commission, the key
technological challenge is how to deal with many users trying to download
information from the Web wirelessly at the same time in the same cell or
geographical area."
Having more than one antenna also would increase the accuracy with which
wireless systems receive the codes. The accuracy can be increased by
about 100 times when two antennas are used instead of one. However,
adding more antennas poses new challenges, because they will increase
power consumption for portable equipment.
Zoltowski says some of that increased power consumption will be offset by
power savings that accrue because of the reduced interference.
The research was funded by the National Science Foundation and by Texas
Instruments' Digital Signal Processing University Research Program.
* Exercise May Slow Some Effects of Aging
NEW YORK (Reuters, 17/5/00) -- Until scientists discover the fountain of
youth, middle-aged and elderly individuals may be able to slow -- if not
yet halt -- some of the effects of aging on the cardiovascular system
using exercise, researchers report.
To get the desired results, people--with their doctor's approval--need to
participate in strenuous exercise for at least a half-hour three times a
week, according to researchers at Bloomsburg University in Pennsylvania.
That conclusion is from an analysis of 37 studies including 720 adults
aged 46 to 90. The findings are published in the Journal of Sports
Medicine and Physical Fitness.
In those studies, people who participated in at least 30 minutes of
exercise three times a week and achieved at least 80% of VO2 max--the
maximum oxygen consumption, which is a measure of the ability to
transport and use oxygen during exercise--can slow the decline in
cardiovascular health that accompanies old age.
Individuals who exercised at this level for more than 15 weeks showed no
significant benefits over those who exercised for less than 15 weeks,
suggesting that improvements can be made in less than 4 months and then
maintained after that point.
The investigators found no difference in fitness between people who
walked and jogged, and those who cycled.
According to the authors, their study findings provide support for the
idea that physical activity can help slow the decline of the
cardiovascular system seen in elderly people.
"Despite the inevitable decline in VO2 max (maximum oxygen consumption)
with aging, exercise training imparts favorable adaptations in functional
capacity in individuals well into the seventh and eighth decades of
life," L.M. Lemura and colleagues conclude.
The researchers write that the heart's capacity to use oxygen declines at
a rate of about 1% a year, due in part to a lack of physical activity.
"The scientific evidence has suggested that significant improvements in
cardiovascular and musculoskeletal function can occur as a result of a
sufficient training stimulus; that is, an adequate intensity, duration,
frequency, and mode of exercise," the authors explain.
* Arteries of Angry Young People Harden Sooner
HealthSCOUT, 17/5/00 - Researchers are showing that feelings of hostility
make blood vessels of younger people become harder and narrower,
increasing the long-term risk of heart attack or stroke.
Over a 10-year period, people who ranked highest on a self-evaluation
scale measuring hostility, distrust and cynicism had significantly more
calcification -- hardening -- of the arteries than those more at peace
with themselves and the world, a group led by Dr. Carlos Iribarren at the
Kaiser Permanente Medical Care Program in Oakland, Calif., reports in the
May 17 issue of the Journal of the American Medical Association.
"This is the first time that a relationship is reported between clinical
calcification and hostility," Iribarren says. "This is a good indication
of atherosclerosis, which is already happening as early as the second
decade of life."
Other studies have established a link between feelings and heart disease.
Just last month, a group led by Janice E. Williams, a researcher at the
University of North Carolina, reported that persons ranking highest in a
scale measuring anger were three times more likely to have a heart attack
or suffer sudden cardiac death than those at the low end of the scale.
"He is looking at the mechanisms by which that happens," says Williams.
"We need more papers like that."
The team led by Iribarren, who is director of research at the Kaiser
Permanente program, has been following 374 men and women who were 18 to
30 years old when the study, called the Coronary Artery Risk Development
in Young Adults, started. Periodically, the researchers use an advanced
technique called electron-beam computed tomography to examine the state
of their arteries.
The effects start early They are looking for the first signs of
atherosclerosis, the buildup of deposits that make blood vessels
narrower, rougher and more calcified. That buildup is the road to
complete blockage of an artery that results in a heart attack or stroke.
More than a decade ago, the participants filled out a 50-question Cook-
Medley scale test, a standard measure of feelings. They were asked how
much or little they trusted other people, how cynical a view they had of
the world, and how they expressed those feelings verbally. Examinations
of their arteries five and 10 years after the study began showed a direct
relationship between feelings and physical effect.
"This prospective cohort study suggests that high hostility levels may
contribute to early subclinical atherosclerotic coronary artery disease,"
the journal report says. "Clinical trials are needed to test whether
reduction in hostile attitudes and behaviors is an effective means of
preventing atherosclerosis."
Even as his group prepares to do the 15-year examination of the
participants' arteries, Iribarren says he has had "some preliminary
discussions with colleagues in the field" about such a trial. "This study
provides a rationale to do it," he says.
One link between feelings and physical damage is the effect of the stress
hormones that surge during times of hostility and anger, Williams says.
"Excess amounts of stress hormones cause damage to the arteries and heart
muscle and also cause the heart to beat irregularly," she says. "Arteries
can be interrupted by constriction and blood clots can form."
Can lessons in controlling anger and hostility reduce the risk? "We just
don't know," she says.
There is no simple recipe for controlling hostility, Iribarren says. The
Kaiser Permanente plan does have anger management classes, which can
help, but the best prescription is "whatever works best for you," he
says.
"You get a triple benefit," Iribarren says. You feel better, you make the
world a better place, and you help your health in the long run. He adds,
"You have nothing to lose."
What To Do If you have continuing feelings of hostility and anger ask
your physician about counseling and other measures to control them.
You're not just hurting other people by being a hothead; you're harming
your health.
* Cancer Threat From Dioxin Greater Than Thought
WASHINGTON (UPI, 17/5/00) -- Dioxin, a highly toxic chemical that people
can ingest through food from a normal diet, has been found to pose an
even greater health risk than previously believed.
The Washington Post reported Wednesday that a draft report by the
Environmental Protection Agency for the first time will claim that dioxin
causes cancer in humans. While emissions of the chemical has been
dropping off since the 1970s, the substance still poses a danger after
being linked to lymphomas, lung and other cancers, the newspaper said.
Dioxin was a part of Agent Orange, the defoliant used by U.S. forces in
Vietnam. In 1983, the discovery of dioxin in the streets of Times Beach
in eastern Missouri, led the government to relocate the town's citizens
and raze the town.
The report claims that dioxin could be responsible for as many as 100 of
the 1,400 deaths each day attributed to cancers.
The Post reported that exposure to the chemical is cumulative. Most of
those people exposed to dioxin ingest the substance as part of their
normal diet. Dioxin, which occurs naturally but is also appears from
industrial sources, enters the food chain when animals eat plants
contaminated with the chemical. Dioxin accumulates in the fat of mammals
and fish, putting people who eat a large amount of fatty foods at greater
risk, the Washington Post said.
Previously the EPA put the chance of those individuals developing cancer
because of dioxin at about 1 in 1,000. The new report increases the
chances to about 1 in 100, the Post said.
According to the report, low level exposure to dioxin has been linked to
diabetes and birth defects.
The Post said the EPA report is to be released in June.
* Gene Therapy for Hearing Loss May Be Possible
NEW YORK (Reuters, 17/5/00) -- Loss of tiny hair cells in the inner ear,
such as after exposure to loud noise, can result in irreversible hearing
loss and problems with balance. In an unexpected finding, researchers at
Genentech Inc. have demonstrated that they can induce production of inner
ear hair cells in rats, something once thought impossible to achieve
after birth.
The researchers hope that their finding may one day lead to gene therapy
to treat hearing and balance impairments.
Drs. Wei-Qiang Gao and J. Lisa Zheng present their findings in the June
issue of Nature Neuroscience.
Hair cells, located in the part of the inner ear called the cochlea, are
part of the hearing apparatus. They are electromechanically sensitive,
responding to both sound and motion. Gao explained to Reuters Health that
"hair cell regeneration occurs spontaneously in post-embryonic and mature
bird and lower vertebrate ears," but was not thought possible in mammals.
The San Francisco, California investigators showed that a specific gene,
called Math1, associated with hair cell production during early embryonic
life, could be induced to produce new hair cells much later, suggesting
that "mammalian inner ears retain the competence to produce new hair
cells even after birth," Gao said. In addition, the team successfully
"identified ... cell types which can differentiate into new hair cells in
the inner ear," the researcher noted.
In Gao's view, these findings hold the potential for significant
therapeutic importance "because hair cell loss due to loud sounds, aging,
and drugs (toxic to the ear), is one of the major causes of hearing loss
(affecting) millions of people."
The ability to replace hair cells damaged or lost with new cells through
gene therapy would represent a great "benefit (to) those suffering from
hearing and balance disorders," Gao explained.
Future research efforts for the team will include determining whether
hair cell growth can be induced in adult mammals. "It should be
recognized that our work is done in postnatal rat cochleae which are
still immature," Gao stressed. "Similar experiments need to be performed
in mature mammalian cochleae before any clinical trials can be
considered."
* Blood Sugar Might Hint at Cancer Risk - Could Give Early Clue Of Chance
for Pancreatic Cancer
HealthSCOUT, 17/5/00 - If your body has trouble using blood sugar
properly, it may be a signal to doctors that you're at risk for cancer of
the pancreas, new research reveals.
A 35-year study of 139 people in the Chicago area shows that those who
had the most trouble metabolizing blood sugar had more than twice the
risk of dying from pancreatic cancer. Results of the study appear in the
Journal of the American Medical Association.
"Pancreatic cancer is unusually difficult to diagnose," says lead author
Susan Gapstur, an assistant professor of preventative medicine at
Northwestern University in Chicago. "With pancreatic cancer being the
fifth most common cause of cancer mortality in the U.S., our problem has
been that, by the time you find the cancer, it has spread to other parts
of the body."
"Its high mortality rate can often be associated with the late stage at
which it is diagnosed," Gapstur says.
Researchers suspected that diabetes might be linked to pancreatic cancer,
she says.
"The issue has been, is diabetes a risk factor or is it a consequence of
the tumor?" she says. "So what we did is look at people who didn't tell
us they had diabetes and studied the relationship between glucose levels
in the blood and pancreatic cancer."
The pancreas is a digestive gland that makes enzymes and hormones to
regulate blood sugars. About 28,000 Americans will be diagnosed with
pancreatic cancer this year. As many as 20 different tumors may attack
the pancreas -- all under the heading of pancreatic cancer. Each tumor
can require different treatment, and each can have its own unique
prognosis.
Gapstur and her colleagues looked at data on men and women, ages 15 to
90, who had participated in a 10-year study from 1963-1973, called the
Chicago Heart Association Detection Project in Industry Cohort.
Participants had been given 50 grams of sugar orally and then had blood
drawn within an hour so that researchers could measure their blood
glucose, or sugar, levels.
Gapstur examined the death records of the participants and matched them
to the initial blood glucose records.
"Overall there was a 2.2-fold higher risk of pancreatic cancer mortality
for those in the highest level compared to those in the lowest level of
blood sugar concentration," she says.
"What we see is a positive relationship, that high glucose could be a
risk factor and that the finding should definitely be explored further,"
she says.
But that's not all Gapstur found.
"What we also saw was a positive relationship between the Body Mass Index
[a measure of body fat] and serum uric acid in men's urine and pancreatic
cancer," she adds. "Body Mass Index and higher levels of uric acid are
both related to high insulin levels, and so all of these thing are
pointing to a common cause: high glucose levels."
Uric acid, one of the body's waste products, usually is excreted by the
kidney. However, uric acid can crystallize, causing kidney stones and
gout.
"What we believe is that all of these things could be working in concert
to play a role in abnormal glucose metabolism, and these may be related
to the risk of pancreatic cancer," Gapstur says.
"There's lots of implications here," she says. "Research could be focused
on effective strategies aimed at modifying lifestyle factors such as
smoking, diet and physical activity, which are factors associated with
high glucose levels and diabetes."
What To Do For more information on pancreatic cancer, check out the
Pancreas Cancer Web, sponsored by Johns Hopkins Medical Institutions, in
Baltimore. And, to learn more about high blood sugar levels and what to
do about them, visit the American Diabetes Association online.
oOo
Have Your Blood Sugar Checked
By Bruce Hensel, M.D.
Blood sugar is regulated by the hormone insulin, which is secreted from
the pancreas.
If your body makes less insulin, or if your cells become resistant to
insulin (which can happen to those who are severely overweight or have
Type 2 diabetes), blood sugar levels may rise.
If a change in blood sugar indicates an early pancreatic cancer, the
finding could be lifesaving. Many pancreatic cancers are not caught until
it's too late.
The bottom line is that you should have your blood sugar checked
regularly. Ask your doctor how often you need the test.
* Is Your Child Protected From the Measles?
By Dr. Bruce Hensel
Many kids are not getting the immunizations they need, and research shows
the measles vaccine doesn't always work. As a result, the incidence of
measles is on the rise. A study found that children who don't get
vaccinated are 35 times more likely to get the measles. The information
comes from the Journal of the American Medical Association. That study
also found that kids who aren't vaccinated put other kids at risk for the
measles. If you're not sure if your child is immune to measles, a simple
blood test can give you the answer. If you had the measles as a child,
you're immune. If you got the shot after 1959, you may need another one.
Ask your doctor and protect yourself and your community at the same time.
* Poor Health in Women Linked to Emotional Abuse
HealthSCOUT, 17/5/00 - Women who are in physically abusive relationships
are known have more physical problems than women who aren't battered. But
emotional wounds may cut as deeply.
Women whose husbands or boyfriends emotionally assault them are far more
likely than those in healthy relationships to develop serious physical
problems, from chronic pain to gastric trouble, new research shows.
Indeed, the scars of such stress appear to be as strongly etched on the
body as they are on the mind.
Experts say the study, believed to be the first to link emotional
violence to chronic health trouble, underscores the need to screen women
for signs of domestic abuse even if they don't have bruises and breaks
that most dramatically expose such behavior.
"I'm not surprised at all" by the report, says Lisa James, senior program
specialist at the Family Violence Prevention Fund, a San Francisco-based
women's group. "In focusing only on the physical violence we've really
underestimated the true damage that emotional abuse can have on a
person's health and well-being."
The latest work, which appears in the May issue of the Archives of Family
Medicine, was led by Ann Coker, an epidemiologist at the University of
South Carolina's School of Public Health in Columbia.
Coker and her colleagues interviewed more than 1,150 women, ages 18 to
65, about their history of physical and emotional abuse by an intimate
partner. More than 53 percent reported being subjected to either or both
forms of violence. About 13 percent said they had been abused
psychologically but not physically -- through intimidation, deprivation
of power and control, and terrorization.
Poor health risk rises 70 percent Victims of this kind of emotional
battering were roughly 70 percent more likely than those in healthy
relationships to develop poor mental and physical health, the researchers
say. They missed more work due to disability, had nearly twice the rate
of chronic pain and a 70 percent greater risk of arthritis.
They had 80 percent higher odds of having a sexually transmitted disease,
their risk of spastic colon was more than 3.5 times greater, and they
were 2.3 times more likely to suffer from stammering.
Coker says emotional abuse could affect a victim's physical health in two
ways -- either by preventing her from seeking treatment for other
conditions, or through chronic stress, which has been shown to affect
everything from the intestines to the immune system.
On the other hand, she notes, she and her colleagues found some evidence
that women in violent relationships may seek more clinic treatment than
other women, and thus may be more likely to be diagnosed with health
problems. They are now conducting a follow-up study of this issue.
Coker's study was released the day before the U.S. Supreme Court ruled
that battered women could not bring suit against their abusers in federal
court under the 1994 Violence Against Women Act. Critics of the decision,
handed down by a strongly divided court, say it severely weakens the 1994
law.
* Whitening Your Smile?
Ask Dr. Weil, 18/5/00
Q. Is tooth whitening safe? Something about putting bleach on my teeth
gives me the creeps! -- Long Time Reader
A. You're right to be skeptical about tooth whitening. While the process
appears to be safe in the hands of an experienced dentist, you do have to
be cautious with the tooth whitening kits sold over the counter. The
bleach these products contain can be harmful to your gums and other oral
tissues and can even damage the enamel on your teeth and the pulp inside
them. There is also some concern that the hydrogen peroxide in teeth
whiteners can enhance the effects of carcinogens.
According to the American Dental Association (ADA), teeth can be whitened
in several ways. Your dentist can do chairside bleaching, a procedure
that takes about an hour. With this method a shield is placed in your
mouth to protect your gums from the bleaching agent that is painted onto
the teeth. A special light may be used to help activate the whitening
agent. There is some risk that your teeth may become temporarily
sensitive to heat and cold after this treatment.
Dentists also whiten teeth by customizing a mouth guard for you and
giving you a gel to use with it. At home, you squeeze some gel into the
mouth guard, which you then wear for up to two hours daily for about two
weeks. You're not a good candidate for this procedure if your gums are
receding or if you habitually use tobacco or alcohol.
So far, the ADA hasn't evaluated the safety or effectiveness of whitening
teeth with lasers, so I'd steer clear of this method until more is known.
Dentists have also expressed concern about over-the-counter whitening
kits, primarily because the mouth guards they contain don't fit reliably.
Kit manufacturers argue that their products make the process more
affordable: Do-it-yourself kits cost about $20, while dentists charge up
to $600 for their whitening procedures. But the other big point to
consider, as the ADA notes, is that not all teeth respond to whitening in
the same way. Yellowish teeth probably will bleach well, while brownish-
colored teeth tend not to, and grayish-hued teeth may not bleach at all.
Talk to your dentist, and if you aren't a good candidate for tooth
whitening, investigate other cosmetic dental procedures such as bonding
or porcelain tooth veneers.
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Before you buy.