|
|
JUNE 2000 CONTENTS
|
Vital Signs
|
Earlier, easier cancer detection
A new noninvasive method for detecting mutations in DNA might one
day be used to detect cancer years before disease symptoms arise,
according to Hopkins oncology researchers who are developing the
technique. Their method identifies mutations in the DNA of mitochondria, the bean-shaped, energy-producing organelles found in the cytoplasm of cells. The researchers demonstrated that these mutations are associated with tumors and can even be detected in bodily fluids of cancer patients, for example in the urine of a patient with the very earliest stages of bladder cancer. "This test is very, very sensitive," says Makiko Fliss, a postdoctoral fellow and first author of the paper that appeared in the March 17 Science. "If you have only five to six tumor cells in the bladder, it could probably detect it." Identifying cancer at such an early stage, of course, has enormous advantages for treatment. Fliss and her colleagues tested mitochondrial DNA from bladder, head and neck, and lung tumors from 20 patients, finding mitochondrial DNA mutations in all of the bladder and lung cancer patients and most of those with head and neck cancer. The scientists also applied the test to samples of bodily fluids (urine, saliva, or bronchial fluids) from several of the same patients, and found the same mitochondrial DNA mutations. Since their report in Science they have confirmed their results on many more patients. When tumor cells die, they are sloughed off into the blood and other bodily fluids, explains Fliss. Making use of such bodily fluids to screen for cancer would allow patients to avoid the pain and discomfort of invasive tests, such as a test for bladder cancer that involves threading through the urethra a tiny camera on the end of a catheter. It would also be less expensive and allow for earlier detection. Whether or not mutations in mitochondrial DNA contribute to cancer is not clear, says David Sidransky, professor of otolaryngology and oncology and senior author on the paper. But regardless of whether mitochondrial DNA mutations help cause or simply accompany cancer, they might still be useful signatures of the disease. In previous research conducted over the past several years, Sidransky and his colleagues developed cancer diagnostic tests that screen for mutations in nuclear DNA (of which chromosomes are made). The tests, which are now in clinical trials, are showing promise of being highly accurate.
However, his new method, screening for mutations in mitochondrial
DNA, offers an advantage. That's because each cell contains only
two copies of each chromosome, and thus only two copies of any
particular mutation that occurs in chromosomal DNA. But several
hundred to thousands of mitochondria reside in the cytoplasm of
each cell, each one bearing a clone of any mutation. As a result,
the signal from mitochondrial mutations is 20 to 200 times
stronger than the signal from nuclear DNA mutations, according to
the researchers. Thus, even if only a few cells bear mutations in
mitochondrial DNA, the new technique could probably detect
them.
|
|
Ooo-la-la! Pain relief that's a fantasy Research projects are often crafted as scientists huddle over graphs and charts in the laboratory or debate the significance of new findings in a conference auditorium. But sometimes ideas spring from more pedestrian sources--like a supermarket tabloid. Such was the case for Hopkins anesthesiologist Peter Staats, director of the Division of Pain Medicine. Staats and his colleagues had developed a broad theory of pain. It encompassed aspects of biology, behavior, and emotion, and said that the perception of pain was closely tied to emotions. In 1995, the researchers tested this theory on volunteers who were asked to plunge a hand in a tank of ice-cold water and keep it there as long as possible. Staats then discovered that various messages could increase or diminish their tolerance to pain. For example, volunteers who were told positive things during the experiment, such as, "Ice water has the ability to heal," reported less pain than a control group of volunteers. Researchers in the pain field gave the study and underlying theory high marks. However, it garnered little media attention. A few years later, Staats' secretary, Linda Stevens, was thumbing through an issue of the National Enquirer. There she found a story about the pain study. Or, at least, it was an Enquirer version of the study. A reporter had inventively penned: "Sexy thoughts banish pain." "It was quite humorous," says Staats. "But it had nothing to do with my study. I'd never been interviewed by the National Enquirer." But, Staats got to thinking, maybe there is something to the notion that sexual fantasies reduce pain. So he and his colleagues repeated their experiment, this time asking college student volunteers to think of a sexual fantasy while they kept a hand in the ice water. Other students were given more mundane topics, such as walking to class, or were not told to think about anything in particular. During the experiment, the students were asked questions about their mood, worries, and degree of pain. Indeed, the researchers found, volunteers who lost themselves in sexual fantasies reported less pain, just as the Enquirer had foretold. Staats reported the results this past October at the annual meeting of the American Pain Society, in Fort Lauderdale. Unlike the earlier study, this report has received widespread media attention, including coverage in USA Today, Penthouse, and The New York Times. It has even become fodder for comedian Jay Leno.
But seriously, folks...the study also supports the theory that
pain and emotion are linked. Notes Staats, "Emotions are likely
processed in the thalamus, a region of the brain also closely
involved in processing pain responses." Further, the study
suggests that patients might be able to effect some of their own
pain management, using their minds.
The more the deadlier, for teen drivers
The risk that a teenage driver will be killed in a car crash
increases with every passenger in the vehicle, according to a
recent School of Public
Health study.
Sixteen- and 17-year-old drivers who carry three or more
passengers have triple the risk of dying in a car crash, compared
to solo drivers in that age group.
"It's possible that when teenagers drive with peers they may be
more likely to speed or run red lights. They may be encouraged by
their peers [to drive hazardously] or try to impress them,"
suggests lead author Li-Hui Chen, a research associate in
Health
Policy and Management, who published her results in the March
22
Journal of the American Medical Association.
Chen and her colleagues also found that the risk was highest for
male teenage drivers carrying three or more passengers. And
driving at night greatly increased teen driver fatality rates.
In contrast to the teen statistics, the risk of dying in a car
crash for drivers in their 30s through 50s declined with
passenger number.
|
|
Gynecology: Not just for gals anymore "Let's face it, guys. Most of you wouldn't know a Pap smear from a reindeer. You probably think that a vulva is a Swedish sports sedan. You know your girlfriend's got PMS, but you'd rather join the Witness Relocation Program than learn anything about it. The long and short of it is, when she comes home from the gynecologist, trying to discuss the exam with you is like trying to get the pope to do a condom commercial."
So write Udo Wahn, MD '75, and Bruce Bekkar, in Your Guy's
Guide to Gynecology: A Resource for Men and Women (Ant Hill
Press, 2000). Both are OB/GYNs at the University of California at
San Diego; they argue that despite men's ignorance or reluctance
to know about their partners' reproductive health, men ought to
learn more; a woman's reproductive health affects her partner's.
In their book, Wahn and Bekkar provide information on birth
control, endometriosis, hysterectomy, uterine fibroids, and other
"female-only" topics, interspersed with quizzes and answers to
many commonly asked questions.
Why schizophrenia hits men harder
One of the many puzzling characteristics of schizophrenia is that
men generally suffer from the mental illness more severely than
do women. Symptoms appear in males years before they do in women,
and men overall are less responsive to medication. Now, recent
imaging studies in a Johns Hopkins lab suggest that the way
schizophrenia shapes the brains of men and women may underlie
these gender differences.
Researchers led by
psychiatrist Godfrey Pearlson focused on a
part of the cerebral cortex called the inferior parietal lobule
(IPL)--a sort of neural crossroads where pathways from many
different brain structures converge. Each hemisphere of the brain
contains an IPL. On the left side, the IPL is involved in visual
perception and spatial relationships, such as gauging how fast a
ball is moving. On the right side, the IPL governs a person's
understanding of where each body part is in relation to another,
a skill that is used in rock climbing or ballet, for example. The
right IPL also comes into play in judging how another person
feels by reading his or her facial expression or body posture.
In a previous study involving healthy volunteers, Pearlson and
his colleagues found that men have a larger IPL than women (even
after the volumes were adjusted for the relatively larger size of
men) and that their left IPL is larger than their right. In
contrast, healthy women had a reverse asymmetry: their right IPL
was slightly larger than their left.
In the recent study, the researchers compared MRI brain scans of
30 schizophrenic men and women with scans from 30 healthy
closely matched volunteers. They used a software program created
by Hopkins psychiatrist and
biomedical engineer Patrick
Barta that uses MRI data to calculate IPL volume.
The results showed that schizophrenic men have a reversed
asymmetry in the IPL, compared to healthy men. Their right IPL is
larger than their left. Further, the overall size of the IPL of
schizophrenic men is 16 percent smaller than it is in healthy
men. Women with schizophrenia did not show significant
differences in IPL size or asymmetry compared to healthy
women.
The gender differences in IPL size and asymmetry could underlie
clinical differences seen in men and women with schizophrenia,
say the researchers, who reported their recent findings in the
March issue of the American Journal of Psychiatry. Men who
have
schizophrenia generally begin showing signs of the illness
between ages 15 and 20, compared to ages 20 to 25 for women.
Likewise, "men have more subtle neurological abnormalities," says
Pearlson. "They have more deficit symptoms such as a lack of will
and directed energy. They [have difficulty] planning, completing
things, or making decisions."
Although schizophrenia is best known for its hallucinations and
delusions, those symptoms are often easier to treat than the
broader, subtler deficits. As a result, women schizophrenics are
more likely to marry, hold a job, and live relatively normal
lives. But schizophrenic men often have symptoms that persist,
and they tend to have more personal troubles such as being
unemployed or homeless, Pearlson says.
"There is probably something in the whole circuit of which the
IPL is part that gets miswired in schizophrenia," says Pearlson,
who with his colleagues has identified other anatomical
differences in the brains of schizophrenics. Understanding such
differences, says Pearlson, could lead to interventions for
delaying the onset or diminishing the severity of schizophrenia
in people who are at risk, he says.
The IPL develops relatively late in adolescence or in early
adulthood, notes Pearlson. "Because the brain is so plastic, if
we could identify people at risk for schizophrenia, and give them
some cognitive training, perhaps we could strengthen other areas,
which could compensate for deficits in the IPL." Currently,
however, he adds, "that is a highly hypothetical
possibility."
Doctors in the movies
Peter Dans became a movie buff while growing up on New York's
Lower East Side in the 1940s; he frequently escaped his family's
cold-water flat to spend long afternoons at the Tribune
Theater.
Dans, an associate professor of
medicine at
Hopkins, was able to
indulge in his passion once again while researching and writing
Doctors in the Movies: Boil the Water and Just Say, "Aah"
(Medi-Ed Press, 2000). The book, the product of thousands of
hours of movie watching, examines how movies reflect changes in
medicine and the way society perceives doctors and other
healthcare professionals.
|
|
Dans describes two characterizations of doctors and medical
institutions: the noble and godlike, such as the compassionate
and heroic neurologist Malcolm Sayer (Robin Williams) in
Awakenings; and the evil and conspiring. Perhaps the most
memorable portrayal of an evil health professional is the
notorious Nurse Ratched (Louise Fletcher), who tries to break the
belligerent Randle McMurphy (Jack Nicholson, at left) in One
Flew Over the Cuckoo's Nest. --MH
A new doctoral program for Nursing
The current trend toward cost-cutting in the nation's health-care
system has prompted the School
of Nursing to launch a new
doctoral program--the Doctor of Nursing Science (DNSc).
The 50-credit program will focus on health outcomes
measurement, healthcare economics, statistical analysis, and
informatics. The goal: to prepare nursing leaders for top spots
in health care systems administration, academia, professional
organizations, and government agencies. Coursework, which will be
offered during the summer and take four to five years to
complete, will focus on analyzing healthcare data in ways that
will allow policy-makers to better evaluate patient care, program
quality, and economic outcomes.
The new DNSc program complements the school's existing PhD
program, which focuses on basic discovery and clinical
intervention studies.
RETURN TO
JUNE 2000 TABLE OF CONTENTS.
|
