Genome Sequencing Named Top Scientific Advance Of 2000, AAAS/Science Daily 
Excerpts: "2000 was a banner year for scientists
deciphering the "book of life"; this year saw the completion of
the genome sequences of complex organisms ranging from the fruit
fly to the human. Science marks the production of this torrent of
genome data as the Breakthrough of 2000; it might well be the
breakthrough of the decade, perhaps even the century, for all its
potential to alter our view of the world we live in."
"The editors at the international journal, Science, have
compiled their list of the Top 10 scientific developments for the
year 2000, placing genome sequencing first on the list.
Science's Top 10 research advances, chosen for their
profound implications for society and the advancement of science,
appear in the journal's 22 December 2000 issue.
Genome sequencing steamed full speed ahead this year, as
researchers used a synthesis of biology, chemistry, physics,
mathematics, computer science, and engineering to decode the
script of life in a variety of organisms, from people to fruit
flies.
A year ago, reasearchers had completely read the genome of
only one multicellular organism, the worm, Caenorhabditis elegans.
Now, sequences exist for the yet-to-be-published human
genome, the fruit fly, and the plant geneticists' favorite weed,
Arabidopsis thaliana. The genomes of several microbes have been
sequenced as well, including those that cause cholera and
meningitis. Close on the heels of these successes, the genomes of
the mouse, rat, zebrafish, and two species of puffer fish are also
nearing completion.
Researchers are already reaping new knowledge from these
sequencing efforts, including insights into the diversity of
cancer, the causes of aging, and the complexity of the immune
system. In the 21st century, researchers will decipher whole
families of genes and whole pathways of interactive proteins.
These advances will bring with them a host of ethical
questions that we have only begun to address. Yet, genome
sequencing's potential for advancing human health and our
understanding of life has made its allure irresistible.
(...)"
Runners up:
- RNA Runs the Ribosome: (...) RNA's
starring role of in the ribosome may support the idea that life
on Earth began with RNA. (...)
- First Out of Africa: Fossil skulls, some
1.7 million years old and unearthed from the well-dated site of
Dmanisi in the Republic of Georgia, may represent the first
human ancestors to journey out of Africa. (...)
- Plastic Electronics: This year,
electrically conducting plastics formed the basis for a bevy of
technological achievements using cheap and versatile organic
molecules. (...)
- Old Cells, New Tricks: Scientists
delivered a decisive blow this year to the once-canonical
notion that adult cells are wedded to their identities.
- A Watery Solar System?: The possibility of
recent water flow on Mars and further convincing evidence for
an ocean on the Jupiter moon Europa made headlines in 2000.
- Cosmic BOOMERANG: (...) to probe for
fluctuations in the cosmic microwave background, the afterglow
of the Big Bang.
- Receptor Roles: (...) roles of nuclear
hormone receptors, discovering variants of these cell
structures that mediate processes such as cholesterol
metabolism and fatty acid production (...)
- Rendez-Vous with an Asteroid: After
circling the asteroid Eros for less than half a year, the NEAR
Shoemaker spacecraft revealed that the space rock contains some
of the most primitive matter in the solar system.
- Quantum Curiosities: (...) showing that
quantum computers don't need a quantum property called
"entanglement" to solve complex problems at lightening speed.
Transmission Of Information And Herd Behavior: An Application To Financial Markets, PRL
Abstract: We propose a model for stochastic
formation of opinion clusters, modeled by an evolving network, and
herd behavior to account for the observed fat-tail distribution in
returns of financial-price data. The only parameter of the model
is h, the rate of information dispersion per trade, which is a
measure of herding behavior. For h below a critical h* the system
displays a power-law distribution of the returns with exponential
cutoff. However, for h>h* an increase in the probability of
large returns is found and may be associated with the occurrence
of large crashes.
The Price Dynamics Of Common Trading Strategies, arXiv
Abstract: A deterministic trading strategy can be
regarded as a signal processing element that uses external
information and past prices as inputs and incorporates them into
future prices. This paper uses a market maker based method of
price formation to study the price dynamics induced by several
commonly used financial trading strategies, showing how they
amplify noise, induce structure in prices, and cause phenomena
such as excess and clustered volatility.
Excerpt: Under the efficient market hypothesis prices
should instantly and correctly adjust to reflect new information.
There is evidence, however, that this may not be the case: The
largest price movements often occur with little or no news, price
volatility is strongly temporally correlated, short term price
fluctuations are non-normal, and prices may not accurately reflect
rational valuations. This suggests that markets have nontrivial
internal dynamics. Traders may be thought of as signal processing
elements, that process external information and incorporate it
into future prices. Insofar as individual traders use
deterministic decision rules, they act as signal filters and
transducers, converting random information shocks into temporal
patterns in prices. Through their interaction they can amplify
incoming noisy information, alter its distribution, and induce
temporal correlations in volatility and volume.
Working Together In "War Rooms" Doubles Teams' Productivity, U. Michigan/Science Daily
Excerpt: "Teams of workers that labored together
for several months in specially designed "war rooms" were twice as
productive as their counterparts working in traditional office
arrangements, a study by University of Michigan researchers has
found. Results of the study will be presented Dec. 6 at the
Association for Computing Machinery 2000 Conference on Computer
Supported Cooperative Work.
Recently, many companies in the software industry have been
experimenting with putting teams of workers into "war rooms" to
enhance communication and promote intense collaboration, explains
Stephanie Teasley, an assistant research scientist in the U-M
School of Information's Collaboratory for Research on Electronic
Work.
Instead of toiling in separate cubicles, workers sit at
wall-less workstations in one big, open room. The room is
typically outfitted with central worktables, whiteboards and flip
charts to facilitate group discussions. While companies expect
benefits from such arrangements, workers sometimes balk at the
idea, fearing they'll sacrifice privacy and the quiet they need to
concentrate on demanding tasks. The U-M researchers say their
study is the first to closely examine the effects of what they
call "radical collocation" on both productivity and worker
satisfaction.
Teasley collaborated on the project with Mayuram Krishnan
and Judith Olson of U-M and Lisa Covi, who was at U-M when the
work was done but now is at Rutgers University. The group studied
six software development teams at a major automobile company, all
of which had little or no experience working in war room settings.
The researchers evaluated the workers' productivity using measures
commonly used in software development; then they compared the war
room teams' scores with productivity data the company had
collected on software development teams working in traditionally
arranged offices. The researchers also interviewed the workers and
had them fill out questionnaires at the beginning and end of the
project. In addition, they made detailed observations of two
teams---sitting in on meetings and conference calls, watching the
teams solve various kinds of problems and photographing them in
action.
Teams in the war room environments were more than twice as
productive as similar teams at the same company working in
traditional office settings. In a follow-up study of 11 more war
room teams, productivity nearly doubled again, making the war room
teams almost four times as productive as their counterparts in
ordinary offices. The setting alone may not account for all of the
productivity differences; teams working in the war rooms also used
techniques designed to accelerate software development. However,
those techniques could only be carried out by radically collocated
teams, says Teasley. "
-
Excerpt: As noted by Hao Bai-Lin in the preface
to his admirable collection of influential papers on non-linear
dynamics, the discovery of chaos in ecological difference
equations, as much as anything else, fertilized a flowering of
interest in this subject some twenty-five years ago. Perhaps not
surprisingly, it was in the physical, as opposed to the
biological, sciences that ``chaos theory', as it is often (and
inaccurately!) referred to, really took hold. In ecology itself,
the ubiquity of chaos and other non-linear phenomena in both
discrete and continuous models was subsequently confirmed.
At the same time, convincing evidence for chaos in natural
systems proved harder to come by. For example, in the case of
pre-vaccination epidemics of measles in large, first world cities,
what was once judged to be one of the more likely examples of
real-world ecological chaos, is now the subject of divergent
opinion. (...)
Evolution Of Development In Mammalian Teeth, PNAS
Excerpts: According to Roy Lewis in The Evolution
of Man, an evolving mammal worries about nothing more than it does
its teeth. And to a paleontologist, nothing about a mammal matters
more than its teeth. To paleontologists, teeth are the population
markers that microsatellite sequences are to population
biologists. Even when represented by only a single tooth, a fossil
mammal can often be identified by cusp number, relative cusp
positions, and cusp heights, all features that are unfathomable to
the non-paleontologist.
But in this issue of PNAS, Jernvall et al. (2)
penetrate the fascinating 'lost world' of fossil mammals,
blazing a new path connecting molecular developmental biology with
paleontology. Recent work, much of it by these same researchers,
has given us a general framework for understanding the molecular
basis of tooth crown formation, integrating genes and proteins
into our previous histology-based knowledge of tooth development.
(1)
The study of mammalian evolution often relies on detailed
analysis of dental morphology. For molecular patterning to play a
role in dental evolution, gene expression differences should be
linkable to corresponding morphological differences. Because
teeth, like many other structures, are complex and evolution of
new shapes usually involves subtle changes, we have developed
topographic methods by using Geographic Information Systems. We
investigated how genetic markers for epithelial signaling centers
known as enamel knots are associated with evolutionary divergence
of molar teeth in two rodent species, mouse and vole.(2)
- Development
And Evolution Occlude: Evolution Of Development In
Mammalian Teeth, David
Polly, PNAS 2000;97 14019-14021
- Evolutionary
Modification Of Development In Mammalian Teeth:
Quantifying Gene Expression Patterns And
Topography, Jernvall,
J., Keranen, S. V. E., Thesleff, I. Proc. Natl. Acad.
Sci. USA 97, 14444–14448, 2000
In Search Of Ant Ancestors, PNAS
Ants have been very successful in adapting to different
environments. One can expect that ants will also thrive in a world
with higher global temperatures and CO2 levels.
Research at the BioSphere
project in Arizona -where self contained ecosystems including
humans were studied- showed that the atmosphere inside the lab
changed to a degree that is not tolerable for humans and other
animals but that was very viable for ants: Nearly all the
birds and animals and insects that were supposed to thrive inside
died—except for cockroaches and “crazy ants” that
now own the place. (2)
Excerpts: Ants are arguably the greatest success story
in the history of terrestrial metazoa. On average, ants monopolize
15-20% of the terrestrial animal biomass, and in tropical regions
where ants are especially abundant, they monopolize 25% or more.
But ants did not always run the world. They do not appear in the
fossil record until the mid-Cretaceous, and for more than the
first half of their history a period spanning 60 to 80 million
years ants occupied a relatively modest position in the
terrestrial biosphere. To understand the factors, both ecological
and historical, that contributed to the rise of the ants, we
require a clearer picture of the stepwise evolution of the major
ant lineages. Now, Grimaldi and Agosti (1) report in a recent
issue of PNAS the remarkable discovery of a worker ant, preserved
in amber for over 90 million years, that is clearly assignable to
a modern ant subfamily that contains many familiar extant species,
including carpenter ants. Combined with other paleontological and
phylogenetic information, this unexpected fossil strongly
indicates that the diversification of many ant subfamilies
occurred earlier and more rapidly than previously
suspected.
A worker ant preserved with microscopic detail has been
discovered in Turonian-aged New Jersey amber [ca. 92
mega-annum (Ma)]. The apex of the gaster has an acidopore and,
thus, allows definitive assignment of the fossil to the large
extant subfamily Formicinae, members of which use a defensive
spray of formic acid. This specimen is the only Cretaceous record
of the subfamily, and only two other fossil ants are known from
the Cretaceous that unequivocally belong to an extant subfamily
(Brownimecia and Canapone of the Ponerinae, in New Jersey and
Canadian amber, respectively). In lieu of a cladogram of formicine
genera, generalized morphology of this fossil suggests a basal
position in the subfamily. Formicinae and Ponerinae in the mid
Cretaceous indicate divergence of basal lineages of ants near the
Albian (ca. 105-110 Ma) when they presumably diverged from the
Sphecomyrminae. Sphecomyrmines are the plesiomorphic sister group
to all other ants, or they are a paraphyletic stem group ancestral
to all other ants they apparently became extinct in the Late
Cretaceous. Ant abundance in major deposits of Cretaceous and
Tertiary insects indicates that they did not become common and
presumably dominant in terrestrial ecosystems until the Eocene
(ca. 45 Ma). It is at this time that modern genera that form very
large colonies (at least 10,000 individuals) first appear. During
the Cretaceous, eusocial termites, bees, and vespid wasps also
first appear they show a similar pattern of diversification and
proliferation in the Tertiary. The Cretaceous ants have further
implications for interpreting distributions of modern
ants.
- In
Search Of Ant
Ancestors, Ted R.
Schultz, PNAS 2000;97 14028-14029
- A
Formicine In New Jersey Cretaceous Amber (Hymenoptera:
Formicidae) And Early Evolution Of The
Ants, David Grimaldi,
Donat Agosti, Proc. Natl. Acad. Sci. Usa, Vol. 97,
Issue 25, 13678-13683, December 5, 2000
- Biosphere
2 a Joke No Longer ,
ABCNews.com, 6/10/00
Polygyny, Mate-Guarding, And Posthumous Fertilization As Alternative Male Mating Strategies, PNAS
Abstract: Alternative male mating strategies
within populations are thought to be evolutionarily stable because
different behaviors allow each male type to successfully gain
access to females. Although alternative male strategies are
widespread among animals, quantitative evidence for the success of
discrete male strategies is available for only a few systems. We
use nuclear microsatellites to estimate the paternity rates of
three male lizard strategies previously modeled as a
rock-paper-scissors game. Each strategy has strengths that allow
it to outcompete one morph, and weaknesses that leave it
vulnerable to the strategy of another. Blue-throated males
mate-guard their females and avoid cuckoldry by yellow-throated
"sneaker" males, but mate-guarding is ineffective against
aggressive orange-throated neighbors. The ultradominant
orange-throated males are highly polygynous and maintain large
territories; they overpower blue-throated neighbors and cosire
offspring with their females, but are often cuckolded by
yellow-throated males. Finally, yellow-throated sneaker males sire
offspring via secretive copulations and often share paternity of
offspring within a female's clutch. Sneaker males sire more
offspring posthumously, indicating that sperm competition may be
an important component of their strategy.
Altruism And Social Cheating In The Social Amoeba Dictyostelium Discoideum, Nature
Abstract: The social amoeba, Dictyostelium discoideum,
is widely used as a simple model organism for multicellular
development, but its multicellular fruiting stage is really a
society. Most of the time, D. discoideum lives as haploid,
free-living, amoeboid cells that divide asexually. When starved,
104–105 of these cells aggregate into a slug. The anterior
20% of the slug altruistically differentiates into a non-viable
stalk, supporting the remaining cells, most of which become viable
spores. If aggregating cells come from multiple clones, there
should be selection for clones to exploit other clones by
contributing less than their proportional share to the sterile
stalk. Here we use microsatellite markers to show that different
clones collected from a field population readily mix to form
chimaeras. Half of the chimaeric mixtures show a clear cheater and
victim. Thus, unlike the clonal and highly cooperative development
of most multicellular organisms, the development of D. discoideum
is partly competitive, with conflicts of interests among cells.
These conflicts complicate the use of D. discoideum as a model for
some aspects of development, but they make it highly attractive as
a model system for social evolution.
A Mechanism For The Evolution Of Altruism Among Non-Kin, SFI Working Papers
Abstract: The evolution of cooperation often requires
genetic similarity among interactors. For populations that are
divided into groups such that a given trait affects all group
members, this requires positive assortment of individuals into
groups, i.e., that individuals are more similar to other group
members than to the population at large. Several authors have
claimed that mechanisms other than kinship could produce genetic
similarity within groups, but this claim has not been generally
accepted. Here we describe such a mechanism. The process of
"environmental feedback" requires only that the cooperative trait
affects the quality of the local environment, and that organisms
are more likely to leave low quality than high quality
environments. We illustrate this dynamic using an agent-based
model of feeding restraint. The mechanism of environmental
feedback appears to be a general one that could potentially play a
role in the evolution of many kinds of altruism in nature.
Colorado River Clams Provide Benchmark, Science
Abstract: Conservationists have long contended,
largely in impressionistic terms, that 70 years of American dam
building and water diversion have destroyed the biological
richness of the Colorado River delta, a key nursery of marine life
at the end of the Southwest's great watercourse. Now researchers
have confirmed those suspicions, using an important ecological
player--clams--as a quantitative marker.
-
Excerpt: It is essential that we improve food
production and distribution in order to feed and free from hunger
a growing world population, while reducing environmental impacts
and providing productive employment in low-income areas. This will
require a proper and responsible utilization of scientific
discoveries and new technologies. The developers and overseers of
GM technology applied to plants and micro-organisms should make
sure that their efforts address such needs.
Foods can be produced through the use of GM technology that
are more nutritious, stable in storage, and in principle health
promoting--bringing benefits to consumers in both industrialized
and developing nations.
New public sector efforts are required for creating
transgenic crops that benefit poor farmers in developing nations
and improve their access to food through employment-intensive
production of staples such as maize, rice, wheat, cassava, yams,
sorghum, plantains and sweet potatoes. Cooperative efforts between
the private and public sectors are needed to develop new
transgenic crops that benefit consumers, especially in the
developing world.
Concerted, organized efforts must be undertaken to
investigate the potential environmental effects--both positive and
negative--of GM technologies in their specific applications. These
must be assessed against the background of effects from
conventional agricultural technologies that are currently in
use.
Public health regulatory systems need to be put in place in
every country to identify and monitor any potential adverse human
health effects of transgenic plants, as for any other new
variety.
Private corporations and research institutions should make
arrangements to share GM technology, now held under strict patents
and licensing agreements, with responsible scientists for use for
hunger alleviation and to enhance food security in developing
countries. In addition, special exemptions should be given to the
world's poor farmers to protect them from inappropriate
restrictions in propagating their crops
- Transgenic
Plants And World
Agriculture, National
Academy Press, 2000 Prepared by the Royal Society
of London, the US National Academy of Sciences, the
Brazilian Academy of Sciences, the Chinese Academy of
Sciences, the Indian National Science Academy, the
Mexican Academy of Sciences and the Third World
Academy of Sciences
- Technology
to Feed the World, This
webpage compiles and highlights issues in agricultural
biotechnology, and includes links to full-text
reports, articles and sound files
- Genetically
Modified Pest-Protected Plants: Science and
Regulation, This
report explores the risks and benefits of crops that
are genetically modified for pest resistance, the
urgency of establishing an appropriate regulatory
framework for these products, and the importance of
public understanding of the issues
Traffic and Related Self-Driven Many-Particle Systems, arXiv
Abstract: Since the subject of traffic dynamics
has captured the interest of physicists, many astonishing effects
have been revealed and explained. Some of the questions now
understood are the following: Why are vehicles sometimes stopped
by so-called ``phantom traffic jams', although they all like to
drive fast? What are the mechanisms behind stop-and-go traffic?
Why are there several different kinds of congestion, and how are
they related? Why do most traffic jams occur considerably before
the road capacity is reached? Can a temporary reduction of the
traffic volume cause a lasting traffic jam? Under which conditions
can speed limits speed up traffic? Why do pedestrians moving in
opposite directions normally organize in lanes, while similar
systems are ``freezing by heating'? Why do self-organizing
systems tend to reach an optimal state? Why do panicking
pedestrians produce dangerous deadlocks? All these questions have
been answered by applying and extending methods from statistical
physics and non-linear dynamics to self-driven many-particle
systems. This review article on traffic introduces (i) empirically
data, facts, and observations, (ii) the main approaches to
pedestrian, highway, and city traffic, (iii) microscopic
(particle-based), mesoscopic (gas-kinetic), and macroscopic
(fluid-dynamic) models. Attention is also paid to the formulation
of a micro-macro link, to aspects of universality, and to other
unifying concepts like a general modelling framework for
self-driven many-particle systems, including spin systems.
Subjects such as the optimization of traffic flows and relations
to biological or socio-economic systems such as bacterial
colonies, flocks of birds, panics, and stock market dynamics are
discussed as well.
Neural Coding: Higher-Order Temporal Patterns in the Neurostatistics of Cell Assemblies, Neural Comp.
Abstract: Recent advances in the technology of
multiunit recordings make it possible to test Hebb's hypothesis
that neurons do not function in isolation but are organized in
assemblies. This has created the need for statistical approaches
to detecting the presence of spatiotemporal patterns of more than
two neurons in neuron spike train data. We mention three possible
measures for the presence of higher-order patterns of neural
activation-coefficients of log-linear models, connected cumulants,
and redundancies-and present arguments in favor of the
coefficients of log-linear models. We present test statistics for
detecting the presence of higher-order interactions in spike train
data by parameterizing these interactions in terms of coefficients
of log-linear models. We also present a Bayesian approach for
inferring the existence or absence of interactions and estimating
their strength. The two methods, the frequentist and the Bayesian
one, are shown to be consistent in the sense that interactions
that are detected by either method also tend to be detected by the
other. A heuristic for the analysis of temporal patterns is also
proposed. Finally, a Bayesian test is presented that establishes
stochastic differences between recorded segments of data. The
methods are applied to experimental data and synthetic data drawn
from our statistical models. Our experimental data are drawn from
multiunit recordings in the prefrontal cortex of behaving monkeys,
the somatosensory cortex of anesthetized rats, and multiunit
recordings in the visual cortex of behaving monkeys.
Coffee Consumption and the Risk of Coronary Heart Disease and Death, Arch Intern Med
Summary: Results In men, the risk of nonfatal
myocardial infarction was not associated with coffee drinking. The
age-adjusted association of coffee drinking was J shaped with
Coronary Heart Disease (CHD) mortality and U shaped with all-cause
mortality. The highest CHD mortality was found among those who did
not drink coffee at all (multivariate adjusted). Also, in women,
all-cause mortality decreased by increasing coffee drinking. The
prevalence of smoking and the mean level of serum cholesterol
increased with increasing coffee drinking. Non-coffee drinkers
more often reported a history of various diseases and symptoms,
and they also more frequently used several drugs compared with
coffee drinkers.
Conclusions Coffee drinking does not increase the risk of
CHD or death. In men, slightly increased mortality from CHD and
all causes in heavy coffee drinkers is largely explained by the
effects of smoking and a high serum cholesterol level.
-
Excerpt: Stem cells in the brain were able to
repair damaged areas and restore function when stimulated by a
growth-inducing protein, a study by researchers at UC Irvine's
College of Medicine has found.
The study, conducted in rats, is the first to show that
adult brain stem cells can develop into nerve cells in living
adult animals, leading to the replacement of damaged brain tissue.
If the results can be replicated in humans, they may eventually
result in a wide range of new and natural stem-cell based
treatments for stroke, nervous system and spinal cord injury and
diseases like Parkinson's and Alzheimer's that are marked by
degeneration of nerve cells. The study appears in the Dec. 19,
2000, issue of the Proceedings of the National Academy of
Sciences.
James Fallon, professor of anatomy and neurobiology--along
with his colleagues at UCI and researchers at Stem Cell
Pharmaceuticals--found that injecting a human protein called
transforming growth factor-alpha (TGF-a) into damaged areas of the
brain stimulated stem cells to multiply, migrate and differentiate
into a massive number of normal, fully developed nerves. These
cells were then able to repair damage and restore the rats'
movement ability. Injections of TGF-a into normal rat brain tissue
did not stimulate repair; nor does brain damage alone lead to the
development of new cells.
"This study is the first to show that stem cells can be
induced naturally in large enough numbers and drawn to specific
sites of damage, restoring function and replacing damaged cells in
the brain," said Fallon. "The stem cells are already in the brain
and other organs in small numbers. They can be stimulated in the
brain to develop by a growth factor without the need for
transplanting stem cells, embryonic tissue or altered cells from
outside; instead, we've just stimulated cells that are already
there."
Fallon's team includes researchers at Stem Cell
Pharmaceuticals Inc., a Seattle-based firm. Fallon serves on the
board of scientific advisors for Stem Cell, which provided
research support and supplies of TGF-a for the most recent
experiments in the study. In addition, Stem Cell has a technology
transfer license with UCI to explore the roles of this and other
growth factors and nerve-cell receptors in restoring function in
neurodegenerative diseases such as Alzheimer's, Parkinson's and
Huntington's, as well as damage caused by stroke and spinal cord
injury. Stem Cell Pharmaceuticals and Fallon currently are
conducting more experiments in animals to measure the
effectiveness of TGF-a (also called GFA-50). These experiments
will support the initiation of clinical trials in humans.
The researchers found that when they injected TGF-a into the
forebrains of rats, only those with damaged tissue showed signs of
significant cell division, cell migration toward depleted and
damaged areas, and specialization of cells into new cells in the
brain. The new cells appeared to be drawn into damaged areas,
replacing destroyed cells.
Scientists think that the process of stem-cell stimulation
may occur naturally to replace damaged brain tissue. But when a
large brain injury, stroke or degenerative disease like
Alzheimer's strikes, the brain's natural repair mechanism may not
be able to keep up with so much damage. Adding more natural growth
factors like TGF-a to damaged areas may provide the necessary
boost. (...)
-
Excerpt: "Researchers in the University of
Toronto's Faculty of Medicine have discovered that a vaccine may
help prevent and treat the disabling memory loss and cognitive
impairment (dementia) of Alzheimer's disease.
Alzheimer's occurs when toxic biochemical compounds known as
amyloid ß peptides accumulate in the brain, forming amyloid
plaque deposits and injuring nerve cells, eventually causing
dementia. While previous studies have shown that vaccinating
transgenic mice with this peptide could remove the amyloid
plaques, there was never any evidence of improvement in brain
function.
After developing transgenic mice with amyloid plaques and
cognitive impairment similar to those found in human Alzheimer's,
scientists at U of T's Centre for Research in Neurodegenerative
Diseases (CRND) determined that immunization with amyloid ß
peptides blocked both the production of the plaques and learning
impairment.
"Not only were we able to clean up the brain tissue, but we
also prevented the behavioural consequences of Alzheimer's," says
Dr. Peter St George-Hyslop, director of the CRND and a neurologist
at the University Health Network. "Obviously, it is more important
that a treatment or prevention in humans be able to block the
clinical dementia."
St George-Hyslop and his colleagues say the amyloid ß
peptide vaccination is ready to be tested on humans. "Our results
also show that pharmaceutical treatments that are directed at
blocking the formation of the peptide or that accelerate its
removal might also be good ways to treat Alzheimer's either alone
or in conjunction with other interventions like vaccination," says
Christopher Janus, research associate at the CRND and the study's
first author. "In the future there might be a cocktail of
treatments including drugs which block formation and inhibit the
toxicity and then a vaccination which will remove the plaque."
The researchers believe this study provides the final
element of proof that Alzheimer's is initiated by amyloid ß
peptides. "While there are other factors that play a role in the
development of the disease, there is little doubt that these
peptides initiate the process," says David Westaway, associate
professor of laboratory medicine and pathobiology in the Faculty
of Medicine and one of the study's co-authors. "If results from
our laboratory studies hold true in humans, this vaccine might
well play a key part in eradicating the disabling dementia that is
associated with the disease, whether caused by genetic or
environmental factors." "
- University
Of Toronto Researchers Develop Potent Vaccine For
Alzheimer's, U.
Toronto, Science Daily, 12/13/00
- A
Vaccine For Alzheimer's
Disease?, Feature Of
The Week, Nature , Vol 408 12/21-28/00
- A
Learning Deficit Related To Age And Beta-Amyloid
Plaques In A Mouse Model Of Alzheimer's
Disease, G Chen, K S
Chen, J Knox, J Inglis, A Bernard, S J Martin, A
Justice, L Mcconlogue, D Games, S B Freedman, R G M
Morris, Nature 408, 975 - 979 (2000)
- Abeta
Peptide Immunization Reduces Behavioural Impairment
And Plaques In A Model Of Alzheimer's
Disease, C Janus, J
Pearson, J Mclaurin, P M Mathews, Y Jiang, S D
Schmidt, M A Chishti, P Horne, D Heslin, J French, H T
Mount, R A Nixon M Mercken, C Bergeron, P E Fraser, P
St George-Hyslop & D Westaway, Nature 408, 979
(2000)
- Abeta
Peptide Vaccination Prevents Memory Loss In An Animal
Model Of Alzheimer's
Disease, D Morgan, D M
Diamond, P E Gottschall, K E Ugen, C Dickey, J Hardy,
K Duff, P Jantzen, G Dicarlo, D Wilcock, K Connor, J
Hatcher, C Hope, M Gordon & G W Arendash, Nature
408, 982 (2000)
- Model
Behaviour, Paul F.
Chapman, Nature, Vol 408 12/21-28/00
-
Excerpt: (...) Nowadays, mathematicians, computer
scientists, and others have a variety of speedy computer-based
methods for generating hyperbolic patterns and tilings. M.C.
Escher didn't have such technology at his disposal. Neither did
Henri Poincaré and other 19th-century mathematicians who
drew various pictures of the hyperbolic plane. They relied on the
traditional tools of geometry—compass and straight-
edge—to create their diagrams.
In an article to appear in the January 2001 American
Mathematical Monthly, however, Chaim Goodman-Strauss of the
University of Arkansas in Fayetteville suggests what these
procedural details might have been. He offers techniques and
instructions for drawing by hand some tilings of the
Poincaré model of the hyperbolic plane. (...)
- Visions
Of Infinity, Ivars
Peterson, Science News, Vol. 158, No. 26 & 27,
Dec. 23 & 30, 2000, P. 408
