NEUROLOGY
Outlook Improves for Rare Disease
New-variant Creutzfeld-Jakob disease (nvCJD) is becoming a more familiar term,
but it is still far less recognizable than its more colorful bovine equivalent,
"mad cow disease." The latter disease is incurable and fatal both to cows and
humans, although a study reported in
The Economist suggests that therapy
for it may someday be possible.
In the past, the disease was usually communicated from cow to cow through
the now-banned practice of mixing cow bone meal into cattle feed; it was communicated
most often to humans through the ingestion of tainted beef. Despite public awareness
campaigns, it is still a difficult disease to track. Its symptoms surface gradually
over a period of years and can be reliably diagnosed only after death.
Two different manifestations of the same disease, "Mad cow" and nvCJD are
both caused by the ingestion of a prion, a misfolded, defective protein.
A protein's function is intricately tied to its unique shape and composition,
and a folding error most often creates an inert molecule. Prions cause disease
by catalyzing other proteins to misfold as well. As prions accumulate and normal
protein manufacture declines, the effects begin to mimic a viral infection.
Because CJD acts on the brain, attempts to either prevent or correct the misfolding
with drug therapy are limited in effectiveness. Despite promising lab results,
many drugs are unable to cross the blood-brain barrier that protects the brain
from foreign
chemicals.
One new approach is to test drugs previously used in the treatment of brain
diseases and are thus known to be capable of crossing the blood-brain barrier.
Dr. Stanley Prusiner, of the University of California — San Francisco, and his
colleagues have determined that quinacrine, a malaria drug, and the schizophrenia
drug chlorpromazine inhibited the formation of misfolded proteins in cultured
cells. These drugs also seem to clear away misfolded proteins already present.
Bruce Miller, a fellow researcher at UCSF, has begun administering the drugs
to two patients whose symptoms probably indicate nvCJD (an exact diagnosis requires
an autopsy). Anecdotal reports indicate that one woman has regained enough physical
coordination to walk again. Clinical trials of the drugs were set to begin this
fall, and Britain's National CJD Surveillance Unit has announced that it will
be contacting six other suspected victims to inform them of the research.
BIOTECHNOLOGY
Pathogenically Grown Embryos on the Horizon
Despite their revolutionary promise for medical treatments, embryonic
stem cells raise very difficult ethical questions. Harvesting such cells, which
can be encouraged to change into any type of specific human tissue, requires
the destruction of a human embryo.
Scientists in Los Angeles and Massachusetts are working on another option,
according to the Los Angeles Times. They are developing ways to force
an unfertilized egg cell to grow and produce stem cells. The phenomenon is called
"parthenogenesis." The resulting embryo is incapable of growing into a human
being. Jerry Hall, a researcher at the Los Angeles-based Tyler Medical Clinic,
believes the technique "simplifies the moral situation tremendously. . . Because
this embryo lacks the potential to become a child, that implies that it doesn't
have the same status as a normal embryo."
Nearly a century ago, research with sea urchins revealed that egg cells would
begin dividing on their own when given the proper chemical or electrical stimulus.
Researchers working with mouse embryos have been able to sustain them long enough
for stem cells to form. Those embryos self-destruct after several weeks. The
researchers believe that human embryos treated the same way will do the same.
A spokesperson for the U.S. Conference of Catholic Bishops said it was unclear
whether the church would view pathogenically grown embryos as a form of human
life deserving protection.
Unfertilized embryos are only one tactic in a broad effort to derive the benefits
from stem cells while raising fewer ethical questions. Massachusetts-based Advanced
Cell Technology is sponsoring adult stem-cell research in which adult cells
are harvested and egg cell proteins are used to force the cells to revert to
an embryonic state. In testimony before a U.S. Senate committee, Michael West,
the firm's CEO, stated that these cells "would not have the architecture of
an embryo and would not create a pregnancy if put into a uterus."
ENDANGERED SPECIES
Surrogate Parents in the Animal Kingdom
Betsy Dresser has a new pet — an endangered African wildcat. Dresser's
efforts as director of the Audubon Center for Research of Endangered Species,
New Orleans, are the reason the wildcat is more than an embryo frozen in liquid
nitrogen.
Dresser is a leading voice for research intended to avert animal extinctions
through cloning and advanced reproductive techniques, according to an article
in Discover. The African wildcat, named Jazz, was born from an embryo
implanted in the womb of a domestic housecat. It was produced from stores of
material — sperm, embryos, tissue samples — that Dresser has been collecting since
the 1980s.
Interspecies surrogacy appeals to biologists for several reasons. Mothers
from the endangered species may be too rare or not available for research. Surrogate
mothers from species such as cats, sheep, antelope, and cows are often easier
to come by in sufficient numbers.
In addition, new cloning techniques are being developed for the benefit of
endangered species. Normal adult-cell cloning relies on cellular DNA that is
introduced into an egg cell from that species. Endangered species' egg cells
are rare, primarily because they don't store well frozen, unlike sperm cells.
The scarcity necessitates the use of an egg cell from a foreign species, which
can then be implanted into the womb of the surrogate mother.
Other biologists are critical of the project. They argue that publicity over
a few notable successes obscures the fact that the reproductive techniques are
years away from showing any measure of reliability, efficiency, or cost-effectiveness.
David Wildt, head of reproductive sciences at the National Conservation and
Research Center, Washington, DC, compares the research to the now vital artificial
insemination used to captive-breed cheetahs, black-footed ferrets, and giant
pandas. These programs became useful only after scientists spent years studying
each animal's unique reproductive mechanisms. "We learned that cheetahs are
not cows," said Wildt. He is also concerned that surrogate breeding programs
cannot rescue thousands of other endangered vertebrate species. A handful of
individuals cannot create a self-sustaining gene pool, he maintains.
Biologists defend the program by envisioning a frozen zoo, where thousands
of samples from many different species are preserved for a time when cloning
techniques are more advanced. "They take a second look at it when they realize
we're not talking about . . . a genetic bottleneck," said Phil Damiani Advanced
Cell Technology, a Massachusetts firm.
SPIRITUAL HEALTH
Another Study Cites Power of Religion in Healing
A widely held notion states that religious faith speeds healing.
A recent study published in the Journal of Holistic Nursing indicated
that the majority of their sample group of older adults used prayer as a complement
or alternative to medical treatment. According to a new study in Archives
of Internal Medicine, as reported in The New York Times, the questioning
of one's faith can actually prove detrimental to recovery.
The latter survey looked at 596 elderly hospitalized patients and found that
those who "wondered whether God had abandoned me," "questioned God's love,"
or blamed their condition on "the devil" were more likely to have died within
two years. Patients in the study were mostly Christians, with the majority representing
moderate to conservative Protestant denominations.
"We know from quite a bit of research that religion can be a potent resource,"
said Dr. Kenneth Pargament, the study's lead author. "It can be a source of
solutions but it can also be a source of problems . . It's also clear that religion
has a darker side."
Other scientists are not convinced. The number of patients surveyed is quite
small in comparison to the subjects of faith-benefit studies, they say, and
the causes of death could not easily be determined. More than 150 patients could
not be located, even though their omission brought the statistical reliability
of the study into question. "With a tiny effect like this, you have to be very
cautious about bias," stated Dr. David Freeman of the University of California — Berkeley,
who reviewed the study.
Pargament was quick to portray the findings as less fearful than they seemed.
"From Moses to Jesus to Buddha, you see religious figures going through dark
nights of the soul, and through that process they come out steeled and strengthened."
His co-author, Harold Koenig, agreed. "All these are normal feelings, but people
work through them usually, and people who can't . . . are going to have worse
health outcomes."
Copyright © 2001 by the Catholic Health Association of the United States
For reprint permission, contact Betty Crosby or call (314) 253-3477.