|
|
Vaccine
may spell the end of chickenpox
When the new
vaccine against varicella infection, or chickenpox, was approved
by the U.S. Food and Drug Administration in 1995, many wondered
how effective it would be. According to the largest study to
date, Yale researchers have found that it prevents the disease
85 percent of the time, and even in those who develop the disease,
symptoms are almost always very mild. If most children get the
vaccine, the investigators believe that it could one day wipe
out chickenpox altogether.
The study, published
in the March 29 issue of The New England Journal of Medicine,
surveyed 591 children at pediatric practices in New Haven. The
study showed that the vaccine worked as well as predicted and
was especially effective—97 percent—at eliminating
severe cases of the disease, which formerly caused 11,000 hospitalizations
and some 100 deaths each year.
According to
study director Marietta Vazquez, M.D., a postdoctoral fellow
in pediatric infectious diseases, “The effectiveness of
the vaccine as it is used in actual practice is excellent, at
least in the short term. If its use is fairly widespread, the
potential is there for complete eradication of the disease.”
She notes that some questions remain about what will happen as
the prevalence of the disease wanes. “Exposure to chickenpox
tends to boost immunity against chickenpox.”
She said that
it may be too soon to assess the long-term effectiveness of the
vaccine. Vazquez and her colleagues plan to continue their study
to determine whether the vaccine will continue to work as well
over time. For now, she said, “I recommend that every healthy
child a year or older, as well as adults with no previous history
of chickenpox, receive the vaccine.” |
|
|
|
Depression
hastens death for women with HIV
For women with
HIV, depression can be deadly. A Yale study of women with the
aids virus found that death rates for those with chronic depressive
symptoms were two times higher than for those with no depressive
symptoms. Chronic depression was also associated with significantly
greater decline in CD4+ count, an important measure of immune
function.
Clinical levels
of depression have been reported by 30 to 60 percent of women
with HIV. In the first study to look at the association between
depression and the course of AIDS in women, 765 women from four
regions of the United States were followed over a period of seven
years as part of the HIV Epidemiological Research Study. The
findings were published in the March 21 issue of JAMA: The
Journal of the American Medical Association. The study leader,
Jeannette R. Ickovics, Ph.D., associate professor of epidemiology
and public health, said that “although the mechanism for
this effect is not fully understood, it is clear that depression
causes more advanced disease progression. We saw such high rates
that either these women were not getting treatment or the treatment
they received was inadequate. Yet depression is a treatable chronic
disease. If we identify and treat depression among women with
hiv, we have the opportunity to enhance their emotional well-being
as well as extend their years of life.”
Women in the
general population have higher rates of depression than men,
and women with advanced HIV were found to be particularly vulnerable
to the effects of depression, according to the new study. The
findings show that “mental health services should be routinely
integrated with primary care for HIV,” Ickovics said. |
|
|
|
Linking
genes to addiction
Investigators
have long known that genetic inheritance makes a contribution
both to the likelihood that someone who takes cocaine, heroin,
other opiate drugs and tobacco will become addicted and to whether
a person will try the drug in the first place. Recent advances
in genomics have made it possible to begin to track down the
genes responsible for the increased risk of addiction. From there,
scientists hope to be better positioned to develop new and more
effective treatments for drug abuse. Two recent, separate grants
to Yale totaling $9 million from the National Institute of Drug
Abuse (NIDA) are supporting the first-ever large-scale, multi-center
study to identify those genes.
NIDA gave Yale
$6 million to study cocaine dependence in 1999 and then an additional
$3 million last August to study opioid addictions. Tobacco addiction
will also be studied because of the high frequency with which
it can occur with abuse of the other drugs. According to the
studies’ principal investigator, Joel E. Gelernter, M.D.,
associate professor of psychiatry, the project represents a landmark
opportunity to find the genetic basis for the addictions. “The
fact,” he said, “that the genetic contribution [to
drug addiction] is so high means that the odds of us finding
something in terms of specific genes are very good.”
To make such
a finding, however, requires recruitment of some 750 families
at several different sites around the country. The goal is to
recruit addicted sibling pairs and type markers throughout the
entire genome. This will give the investigators a good chance
to identify the more important genes that influence risk for
drug dependence.
Eventually,
the study should result in a better understanding of the physiological
basis of addiction. “The fantasy,” said Gelernter,
“would be that we could do a simple DNA test of someone
whom we thought was at risk early on, and then do some type of
modification of the environment that might be protective. Or
we could put the person on some type of medication before he
or she was ever exposed to cocaine to modify what the risk would
be.” One such medication based on the work of Yale scientists,
a vaccine that can prevent cocaine from getting the user high,
is currently being studied in clinical trials. |
|
|
|
Coming
soon to an operating room near you: HDTV
Most people
think of high-definition television (HDTV) as a technology that
will make their favorite programs appear sharper and more realistic
looking, but an emerging medical use for an HDTV camera system
could have a revolutionary impact on surgery.
Steven F. Palter,
M.D., assistant professor of obstetrics and gynecology, used
a prototype, miniaturized HDTV system during a pilot study in
five endoscopic procedures. He said it was “like looking
through a window when looking at the monitor. The image was as
good as looking directly in the incision as opposed to through
the endoscope in the incision.” He believes the benefits
of the new system will be felt in many medical specialties.
HDTV has two
to three times the normal number of lines on the screen and two
to three times the resolution of video equipment currently used
in endoscopic surgeries. Until the development of the prototype
system, however, the HDTV camera was not sufficiently small or
affordable to be useful in endoscopic procedures. The new system’s
developer, the JVC company, expects to bring it to market sometime
this year.
Palter believes
the value of using HDTV will go well beyond the sharper image.
He is currently doing a larger, follow-up study to see whether
the system has benefits of increased accuracy, reduced surgeon
fatigue and better visualization of disease. He says, “It
is not just the next phase in technology. It will become the
standard for all kinds of endoscopic surgery.” |
