ScienceWeek

SCIENCE-WEEK

A Weekly Email Digest of the News of Science

A journal devoted to the improvement of communication
between the scientific disciplines, and between scientists,
science educators, and science policy-makers.

December 8, 2000 -- Vol. 4 Number 49

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The opposite of a correct statement is a false statement.
But the opposite of a profound truth may well be another
profound truth.
-- Niels Bohr (1885-1962)

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Section 1
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Contents of this Issue (Full reports in Section 2):

1. CHEMISTRY: ON LINUS PAULING
In a new essay on Linus Pauling, it is suggested that it was only
when the idea of electron sharing was accepted and quantified
that the chemical bond came into its very own, and that after
that chemistry had no further need of physics for the rest of the
century. This extrapolation from physics to chemistry and the
articulation of chemistry as an independent subject was the
handiwork of a single individual, Linus Pauling, and Pauling
ranks with Galileo, Da Vinci, Shakespeare, Newton, Bach, Faraday,
Freud, and Einstein as one of the great thinkers and visionaries
of the millennium. (Nature 23 Nov 00 408:407)

2. CHEMISTRY: ELECTRICALLY CONDUCTING POLYMERS
In general, electrically conducting polymers are composed of
conjugated polymer chains with pi-electrons delocalized along the
backbone. In the neutral ("undoped") form, the polymers are
either insulating or semiconducting. The polymers are converted
to the electrically conducting ("doped") forms via oxidation or
reduction reactions which produce delocalized charge carriers.
Last month, three individuals shared the Nobel Prize in Chemistry
for their discovery of conducting polymers in the 1960s and
1970s: Alan Heeger (University of California Santa Barbara, US);
Alan MacDiarmid (University of Pennsylvania, US); Hideki
Shirakawa (Tsukuba University, JP). (Physics Today December 2000)

3. MATERIALS SCIENCE: SYNTHESIS AND PROPERTIES OF NANOTUBES
In general, carbon nanotubes can be formed by any process that
first produces free carbon and then allows the spontaneous
formation of carbon-carbon structures, and there are now three
primary methods of carbon nanotube synthesis in use. The tensile
strength and electrical conductivity of carbon nanotubes are far
greater than those of steel and copper, and carbon nanotubes can
be reversibly bent without fracture. With so many areas of
development underway, it seems clear that it is no longer a
question of whether nanotubes will become useful components of
the electronic machines of the future but merely a question of
how and when. (Scientific American December 2000)

4. BACTERIOLOGY: NEW EVIDENCE AGAINST NANOBACTERIA
Although the presence of fossils of living nanoscale forms in
known meteorites now seems questionable if not refuted, there has
recently been some interest in reports of living nanoscale
entities present as pathogens in mammalian host systems including
humans. But new experimental evidence does not provide plausible
support for the existence of a previously undiscovered genus of
"nanobacteria". Instead, experiments provide evidence that
biomineralization previously attributed to nanobacteria may be
initiated by nonliving macromolecules and transferred on
"subculture" by self-propagating microcrystalline apatite.
(Proc. Natl. Acad. Sci. US 10 Oct 00 97:11511)

5. NEUROBIOLOGY: ON THE HISTORY OF NEUROSCIENCE
In a review of the history of neuroscience, two prominent
researchers point out that the neuroscience of higher cognitive
processes is only beginning. For neuroscience to address the most
challenging problems confronting the behavioral and biological
sciences, we will need to continue to search for new molecular
and cellular approaches and use them in conjunction with systems
neuroscience and psychological science. In this way we will best
be able to relate molecular events and specific changes within
neural circuits to mental processes such as perception, memory,
thought, and possibly consciousness itself.
(Science 10 Nov 00 290:1113)

6. PHYSIOLOGY: ON INSULIN
Since its isolation by Banting and Best in 1922, the hormone
insulin has been the focus of intensive research in biochemistry,
physiology, and medicine. It is known that in addition to their
presence in other tissues, insulin receptors and insulin
signaling proteins are widely distributed throughout the central
nervous system. New evidence now indicates that insulin
participates in the central nervous system control of food intake
and body weight, and the stage is now set for studies to
determine if impaired central nervous system signaling by insulin
and leptin contribute to the pathogenesis of two common metabolic
diseases, obesity and type 2 diabetes.
(Science 22 Sep 00 289:2122)

7. FOCUS REPORTS: ON DARWIN AND HUXLEY

8. FROM THE SCIENCEWEEK ARCHIVE:
ON ACCESS TO ESSENTIAL DRUGS IN POOR COUNTRIES

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Section 2
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1. CHEMISTRY: ON LINUS PAULING
     In every century, every field in science has its personal
_tour de force_, an individual with enormous intellect and
prodigious research output who pushes the field to new
boundaries. In 20th century chemistry, it can be argued that such
an individual was Linus Pauling (1901-1994). On the theoretical
front, Pauling was largely responsible for the immensely
successful extrapolation from quantum physics to chemistry. On
the experimental front, Pauling investigated molecular structures
using quantum mechanics, x-ray diffraction, electron diffraction,
magnetic effects, and heats of reaction to calculate interatomic
distances in molecule and the angles between chemical bonds. He
introduced the concepts of hybrid orbitals, directed valency, the
partial ionic character of covalent bonds, and resonance of
molecular structure. His book _The Nature of the Chemical Bond
and the Structure of Molecules and Crystals_ was the most
influential chemical text in the 20th century. When he moved into
biochemistry, Pauling did important work on the structure of
proteins and the molecular basis of sickle cell anemia. He
received the Nobel Prize in Chemistry in 1954.
     During the last 30 years of his life, Pauling attempted to
break new ground in several other areas in medical biology,
including a theory of anesthesia and the use of high doses of
vitamin C in the prevention and treatment of the common cold, but
these attempts proved dead ends. Many people were saddened to see
the last few decades of Pauling's life clouded by what appeared
to be an almost obsessive search for acclamation. Most biologists
and clinicians never took his vitamin C proposals seriously. As
for his theory of anesthesia, Pauling apparently never understood
that there are many ways to reversibly shut down nerve cells, so
that advocating a single mechanism for all types of anesthesia is
not justified. He certainly did not understand the paramount
physiological difference between general anesthesia and local
anesthesia. But no matter these failures during his later years,
Pauling certainly stands as a formidable colossus of 20th century
chemistry.
... ... Gautam R. Desiraju (University of Hyderabad, IN) presents
an essay on Linus Pauling, the author making the following
points:
     1) The author suggests that it was only when the idea of
electron sharing was accepted and quantified that the chemical
bond came into its very own. After that, "chemistry had no
further need of physics for the rest of the century." This
extrapolation from physics to chemistry and the articulation of
chemistry as an independent subject was the handiwork of a single
individual. "Linus Pauling ranks with Galileo, Da Vinci,
Shakespeare, Newton, Bach, Faraday, Freud, and Einstein as one of
the great thinkers and visionaries of the millennium. Truly he
was not of his age, but for all time."
     2) The author suggests that, in retrospect, it appears that
chemistry was waiting for Pauling. His chapters in _The Nature of
the Chemical Bond and the Structure of Molecules and Crystals_
proceed almost ruthlessly through interatomic distances,
electronegativity, ionic, covalent, and van der Waals radii,
aromaticity and the structure of benzene, multiple bonds,
electron deficient substances, the metallic bond and the hydrogen
bond. "They were a route map for chemical research for the rest
of the century."
     3) The author suggests that chemistry is utterly different
from physics and biology in its dependence, at a primal level, on
just one scientist, and that this raises some awkward questions.
Did Pauling's influence modify, divert, or even stunt the
development of other, perhaps still unexplored or unidentified,
branches of the subject? Are chemists introverted and cautious
because much of their research flows from a single stream of
consciousness, making big imaginative leaps unnecessary? Does
chemistry lack the high drama of physics and the glamour of
biology because these were appropriated by one larger than life
individual? The author concludes: "Chemistry will become a
different subject as it transforms from a unitary to a
diversified science. Will it ultimately delocalize and dissolve
into other disciplines? Only time will tell, but if it does, it
would only be because its very identity depended for so long on
the contributions of a single individual."
-----------
Gautam R. Desiraju: The all-chemist.
(Nature 23 Nov 00 408:407)
QY: Gautam R. Desiraju, School of Chemistry, University of
Hyderabad, Hyderabad 500 046 IN.
-------------------
Summary by SCIENCE-WEEK http://scienceweek.com 8Dec00
For more information: http://scienceweek.com/swfr.htm

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2. CHEMISTRY: ELECTRICALLY CONDUCTING POLYMERS
     In general, electrically conducting polymers are composed of
conjugated polymer chains with pi-electrons delocalized along the
backbone. In the neutral ("undoped") form, the polymers are
either insulating or semiconducting. The polymers are converted
to the electrically conducting, or "doped", forms via oxidation
or reduction reactions which produce delocalized charge carriers.
Charge balance is accomplished by the incorporation of an
oppositely charged counterion into the polymer matrix. The
conductivity is electronic in nature, with no concurrent ion
motion occurring in the solid state. During electrochemical
switching, ions do move into and out of the polymers as charge-
balancing species for the charge carriers on the polymer
backbone. Present and potential applications of conducting
polymers utilize both their electronic (electrically conducting
and optical) properties and their ionic properties (e.g., as
battery or sensor electrodes). Examples of current applications
are: charge-storage batteries, conductive textiles, chemical and
biochemical sensors, electromagnetic shielding and antistatic
coatings, gas separation membranes, electrooptics and
electrochromism.
     Last month, three individuals shared the Nobel Prize in
Chemistry for their discovery of conducting polymers in the 1960s
and 1970s: Alan Heeger (University of California Santa Barbara,
US); Alan MacDiarmid (University of Pennsylvania, US); Hideki
Shirakawa (Tsukuba University, JP).
... ... Barbara Goss Levi (_Physics Today_, US) presents a report
on the work of Heeger, MacDiarmid, and Shirakawa, the author
making the following points:
     1) The story began in the 1960s when Shirakawa, then working
on his PhD thesis, accidentally discovered polyacetylene films.
In the 1970s, Heeger and MacDiarmid began collaborating on a
conducting inorganic polymer [poly(sulfur nitride)], and when
MacDiarmid presented a lecture in Japan in 1975, he met Shirakawa
and was shown Shirakawa's polyacetylene films. Shirakawa was then
invited to the US to work with Heeger and MacDiarmid, where the
group learned to make very pure samples of polyacetylene. They
discovered that by doping polyacetylene with bromine vapor the
conductivity rose by 7 orders of magnitude. Although
polyacetylene proved to be too unstable for applications, this
work provoked intensive efforts by others, and the field of
electrically conducting polymers and their applications quickly
developed.
     2) Levi points out that the details of how polymers carry
current are still not fully understood. A major challenge is to
raise the carrier mobility and the conductivity, which are
currently limited by the defects in the polymers. When cast from
solution as thin films, the polymers remain largely a tangle of
spaghetti-like strands, and transfer along the ideal linear chain
can proceed no further than the length of the fully extended
chain, after which the charge must hop to another chain. As good
as they are, even the best conducting polymers today are still
just on the metallic side of the metal-insulator transition.
However, with improved ordering of the polymer chains the
conductivity could exceed those of even the best metals.
-----------
Barbara Goss Levi: Nobel Prize in chemistry salutes the discovery
of conducting polymers.
(Physics Today December 2000)
QY: Barbara Goss Levi: pt@aip.org
-------------------
Summary by SCIENCE-WEEK http://scienceweek.com 8Dec00
For more information: http://scienceweek.com/swfr.htm
-------------------
Related Background:
ELECTROLUMINESCENCE IN CONJUGATED POLYMERS
In general, a "diode" is an electronic device with two electrodes
in a physical configuration such that the device permits flow of
electric current in one direction only. In general, a
"semiconductor" is a crystalline solid, such as silicon or
germanium, with an electrical conductivity intermediate between
that of a conductor and an insulator. In general, an "orbital" is
a space region in which an electron may be found in an atom or
molecule, the space region essentially a probability distribution
for the electron described by the equations of quantum mechanics.
Since the atoms in a crystalline solid are in close proximity,
the orbitals of their electrons overlap and possible the electron
energy levels are effectively spread into energy "bands".
Electric conduction occurs in semiconductors as the result of a
net movement under the influence of an applied electric field, a
movement of electrons in the "conduction band" and a movement of
empty states (called "holes") in the "valence band". A hole
effectively behaves as an electron with a positive charge, and
electrons and holes are known as the "charge carriers" in a
semiconductor. In general, "electroluminescence" is the emission
of light by a substance as the result of an applied electric
field, and in general, a "light-emitting diode" (denoted as LED)
is a semiconductor device that converts electrical energy into
light or infrared radiation, a radiation wavelength span from 550
nanometers (green light) to 1300 nanometers (infrared radiation).
Research in the use of organic conjugated polymers as the active
semiconductors in light-emitting diodes has advanced rapidly in
recent years, and prototype devices now meet what are viewed as
realistic specifications for applications. Conjugated polymers
derive their semiconducting properties by having delocalized ã-
electron bonding along the polymer chain, with *bonding and
antibonding orbitals effectively forming delocalized valence and
conduction bands which support mobile charge carriers.
... ... R.H. Friend et al (11 authors at 6 installations, UK IT
BE SE) present a review of electroluminescence in conjugated
polymers, the authors making the following points: 1) The
phenomenon of electroluminescence has been seen in a wide range
of semiconductors, and for organic semiconductors was first
reported for anthracene single crystals in the 1960s. These early
studies established that the process responsible for
electroluminescence requires injection of electrons from one
electrode and holes from the other, the capture of oppositely
charged carriers (called "recombination"), and the radiative
decay of the excited electron-hole state (called an "exciton")
produced by this recombination process. 2) Development of organic
thin-film electroluminescence was accelerated in the 1980s
through the work of Tang and Van Slyke, who demonstrated
efficient electroluminescence in 2-layer *sublimed molecular film
devices. These early devices consisted of a hole-transporting
layer of an aromatic diamine and an emissive layer of 8-
hydroxyquinoline aluminum. 3) Since the first report of metallic
conductivities in "*doped" polyacetylene in 1977, the science of
electrically conducting polymers has advanced rapidly. As high
purity polymers have become available, a range of semiconductor
devices have been investigated, including *transistors,
*photodiodes, and light-emitting diodes. Much progress has been
made in understanding the basic science that controls the
properties of these devices, but at the present time, in
comparison with inorganic semiconductors, relatively little is
known about the electronic properties of polymeric
electroluminescent semiconductors, and even the nature of the
semiconductor excitations remains controversial.
-----------
R.H. Friend et al: Electroluminescence in conjugated polymers.
(Nature 14 Jan 99 397:121)
R.H. Friend [rhf10@cam.ac.uk]
-----------
Text Notes:
... ... *bonding and antibonding orbitals: A "bonding orbital" is
a molecular orbital formed by a bonding electron whose energy
decreases as the nuclei of the bonding atoms are brought closer
together, resulting in a net attraction and a chemical bonding.
In contrast, an "antibonding orbital" is a molecular orbital
whose energy increases as the nuclei are brought closer together,
indicating a net repulsion rather than a net attraction.
... ... *sublimed molecular film: Sublimation is the
transformation of system directly from the vapor state to the
solid state (or from the solid state to the vapor state) without
passing through an intermediary liquid state. A "sublimed"
molecular film is thus a solid molecular film formed directly
from the vapor state.
... ... *doped: In general, in this context, "doping" is the
addition of impurities to a semiconductor to achieve desired
conductivity characteristics. Only a very small addition of
impurity is needed to produce material suitable for use in the
manufacture of semiconductor devices. For example, an impurity
content of 1 part in 10^(8) increases the conductivity of pure
germanium and silicon 16 times. As a corollary, production
control of the electrical characteristics of semiconductors
requires extremely pure germanium and silicon at the start, and
this initial purification is one of the most difficult processes
in the manufacture of semiconductor devices.
... ... *transistors: In general, a transistor is a semiconductor
device in which it is possible to control voltage or current in
such a way as to achieve gain or switching action.
... ... *photodiodes: In general, a photodiode is a diode device
whose electrical characteristics are dependent on incident light.
-------------------
Summary & Notes by SCIENCE-WEEK http://scienceweek.com 19Mar99
For more information: http://scienceweek.com/swfr.htm
-------------------
Related Background:
SEMICONDUCTOR-POLYMER INTERFACE TUNABLE DIODE
In physics, the term "tuning" refers to an adjustment of the
response (for example, oscillatory behavior) of a system to an
applied force by changing one or more of the system parameters.
In general, a diode is any two-electrode electrical system, and a
tunable diode is any such system whose voltage-current relation
(force-response characteristic) can be quantitatively tuned by
parameter variation. In physics, the term "work function" is the
minimum energy required to release an electron as it passes
through the surface of a conductor or semiconductor. A conjugated
polymer is a polymer with alternating double and single bonds in
its structure, the conjugation often producing enough electron
delocalization to make the polymer a conductor of electricity.
The term "doping" refers to the incorporation of impurities in a
substance to alter its physical properties. M. Lonergan (Univ. of
Oregon, US) reports experimental observations and analysis of a
tunable diode based on a hybrid inorganic-organic n-indium
phosphide/poly-(pyrrole)/nonaqueous electrolyte architecture.
Electrochemical manipulation of the work function of the
conjugated poly(pyrrole) enables continuous and active tuning of
the diode through a range from 0.0 to 0.6 volts. The author
suggests this type of tunable diode represents a new type of
device architecture that allows the electrochemical control
available with doped conjugated polymers, and that a general path
to diodes with specific properties for specialized applications
is now open.
-----------
QY: Mark C. Lonergan, University of Oregon 541-346-4789.
(Science 19 Dec 97) (Science-Week 9 Jan 98)
For more information: http://scienceweek.com/swfr.htm

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3. MATERIALS SCIENCE: SYNTHESIS AND PROPERTIES OF NANOTUBES
Fullerenes are large molecules composed entirely of carbon,
with the chemical formula C(n), where n is any even number from
20 to over 100. They apparently have the structure of a hollow
spheroidal cage with a surface network of carbon atoms connected
in hexagonal and pentagonal rings. Carbon nanotubes are similar
to fullerenes, except their shape is tubular. They were first
discovered by Sumio Iijima (NEC Laboratories, JP) in 1991, they
come in both multi-wall and single-wall versions, with single-
wall nanotubes having a diameter of approximately 1 nanometer and
multi-wall versions having diameters of the order of 10 to 30
nanometers. There have been rapid developments in understanding
the chemistry and physics of carbon nanotubes, and there is much
excitement in both the materials science and electronics
communities concerning possible applications of these unique
structures. Intensive efforts are currently underway to perfect
the production of carbon nanotubes for various applications.
... ... P.G. Collins and P. Avouris discuss the methods of
synthesis and properties of carbon nanotubes, the authors making
the following points:
     1) In general, carbon nanotubes can be formed by any process
that first produces free carbon and then allows the spontaneous
formation of carbon-carbon structures. There are now three
primary methods of carbon nanotube synthesis in use:
... ... a) Arc discharge method: First reported by T. Ebbesen and
P.M. Ajayan (NEC Fundamental Research Laboratory Tsukuba, JP) in
1992, this method involves production of an electrical spark
between two graphite electrodes. At 100 amps current, the carbon
at the tips of the rods vaporizes into a hot gas, with some of
the carbon recondensing in the form of nanotubes. The typical
yield is up to 30 percent by weight. With high temperatures and
metal catalysts added to the graphite rods, both single-walled
and multi-walled nanotubes can be produced with few or no
structural defects. The major limitation is that nanotubes
produced by this method tend to be short (50 microns or less in
length) and deposited in random sizes and directions.
... ... b) Chemical vapor deposition method: First used by
Morinubo Endo (Shinshu University, JP), this method involves
heating a substrate to 600 degrees centigrade and slowly adding a
carbon-bearing gas such as methane. As the gas decomposes,
released carbon recombines in the form of nanotubes. With use of
a porous catalyst, the method can apparently convert all the
carbon in a feed gas to nanotubes. By printing patterns of
catalyst particles on the substrate, it is possible to control
where the tubes form. The typical yield of the chemical vapor
deposition method is 20 to 50 percent, and this method is the
easiest of the three methods to scale up to industrial
production. The method may be able to make nanotubes of great
length, a necessity if nanotube fibers are to be used in
composites. A limitation is that nanotubes made by this method
are usually multi-wall and often riddled with defects. As a
result, carbon nanotubes produced by this method have only one-
tenth of the tensile strength of those made by arc discharge.
... ... c) Laser pulse method: First used by Richard Smalley
(Rice University, US) and coworkers, this method uses intense
laser pulses to generate a hot carbon gas from which nanotubes
form. The typical yield is up to 70 percent. The method produces
primarily single-wall nanotubes, with a diameter range that can
be controlled by varying the reaction temperature. The major
limitation of this method is that it is by far the most costly,
since it requires extremely expensive lasers.
     2) The important properties of carbon nanotubes are as
follows:
... ... Size: (single-wall) 0.6 to 1.8 nanometers in diameter.
... ... Density: 1.33 to 1.40 grams per cubic centimeter. By
comparison, aluminum has a density of 2.7 grams per cubic
centimeter.
... ... Tensile strength: 4.5 x 10^(10) pascals. By comparison,
high strength steel alloys break at approximately 2 x 10^(9)
pascals.
... ... Resilience: Carbon nanotubes can be bent at large angles
and restraightened without damage. By comparison, metals and
carbon fibers fracture at grain boundaries.
... ... Electric current carrying capacity: Estimated at 10^(9)
amps per square centimeter. By comparison, copper wire burns out
at approximately 10^(6) amps per square centimeter.
... ... Field emission: Carbon nanotubes can activate phosphors
at 1 to 3 volts if electrodes are spaced 1 micron apart. By
comparison, molybdenum tips require fields of 50 to 100 volts per
micron and have very limited lifetimes.
... ... Heat transmission: Predicted to be as high as  6000 watts
per meter per kelvin at room temperature. By comparison, nearly
pure diamond transmits 3320 watts per meter per kelvin.
... ... Temperature stability: Carbon nanotubes are stable up to
2800 degrees centigrade in vacuum, 750 degrees centigrade in air.
By comparison, metal wires in microchips melt at 600 to 1000
degrees centigrade.
... ... Cost: Carbon nanotubes can currently be purchased
commercially for $1500 per gram.
     3) The authors conclude: "With so many areas of development
underway, it seems clear that it is no longer a question of
whether nanotubes will become useful components of the electronic
machines of the future but merely a question of how and when."
-----------
P.G. Collins and P. Avouris: Nanotubes for electronics.
(Scientific American December 2000)
QY: Philip G. Collins, IBM Thomas J. Watson Research Center, US.
-------------------
Summary by SCIENCE-WEEK http://scienceweek.com 8Dec00
For more information: http://scienceweek.com/swfr.htm

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4. BACTERIOLOGY: NEW EVIDENCE AGAINST NANOBACTERIA
Although the presence of fossils of living nanoscale forms in
known meteorites now seems questionable if not refuted, there has
recently been some interest in reports of living nanoscale
entities present as pathogens in mammalian host systems including
humans. In 1998, E.O. Kajander and N. Ciftcioglu (see report
appended below) reported the isolation of "nanobacteria" from
human kidney stones and suggested these entities as etiological
agents of pathological extraskeletal calcification. Similar
nanobacteria had previously been isolated from fetal bovine serum
(fetal calf serum) after prolonged incubation in a tissue-culture
medium (*Dulbecco's modified Eagle's medium). These supposed 
bacteria initiated biomineralization of the culture medium and
were identified in calcified particles and biofilms by nucleic
acid stains, partial DNA sequencing, electron microscopy, and the
demonstration of a transferable biomineralization activity.
Although the authors of the 1998 paper were adamant that the
entities they isolated were indeed living systems, not everyone
accepted their interpretation of their observations.
... ... J.O. Cisar et al (6 authors at 2 installations, US) now
present an experimental refutation of the Kajander and Ciftcioglu
interpretation, the authors making the following points:
     1) The authors report they have identified supposed
nanobacteria, not only from fetal bovine serum, but also from
human saliva and dental plaque after the incubation of 0.45-
micron filtered samples in Dulbecco's modified Eagle's medium
(DMEM). Although biomineralization in such "cultures" was
transferable to fresh DMEM, molecular examination of decalcified
biofilms failed to detect nucleic acid or protein that would be
expected from growth of a living entity. In addition,
biomineralization was not inhibited by sodium azide, which is
known to completely shut down respiration of living systems by
blocking the electron transport pathway. Furthermore, the partial
DNA sequences (16s rDNA) previously ascribed to Nanobacterium
sanguineum and Nanobacterium sp. were found to be
indistinguishable from those of an environmental microorganism,
Phyllobacterium mysinacearum, that has been previously detected
as a contaminant in polymerase chain reaction (PCR) measurements
of DNA.
     2) The authors conclude: "Thus, these data do not provide
plausible support for the existence of a previously undiscovered
bacterial genus. Instead, we provide evidence that
biomineralization previously attributed to nanobacteria may be
initiated by nonliving macromolecules and transferred on
"subculture" by self-propagating microcrystalline *apatite."
-----------
J.O. Cisar: An alternative interpretation of nanobacteria-induced
biomineralization.
(Proc. Natl. Acad. Sci. US 10 Oct 00 97:11511)
QY: John O. Cisar: john.cisar@nih.gov
-----------
Text Notes:
... ... *Dulbecco's modified Eagle's medium: An "Eagle's medium"
is any of various growth or maintenance media used in tissue
culture, the medium essentially consisting of a balanced salt
solution supplemented with amino acids, vitamins, serum, and
antibiotics.
... ... *apatite: A group of phosphate-containing minerals.
-------------------
Summary & Notes by SCIENCE-WEEK http://scienceweek.com 8Dec00
For more information: http://scienceweek.com/swfr.htm
-------------------
Related Background:
A CONTINUING FEUD CONCERNING NANOBACTERIA
     Ultimately, the labeling of a system as "living" or
"nonliving" is an anthropocentric question and perhaps not of
paramount importance in the effort to unravel the workings of
nature. But labels and the categories they name do have utility:
in particular, labels and categories do help us conceptually
organize the enormous variety that nature presents to us. During
the past few years, there has been a strong debate in progress
concerning the use of the label "nanobacteria" to characterize
certain inclusions found in samples of Martian rock, and also
recently in kidney stones. (For details, see the related
background material appended below.)
     These nanobacterial entities are extremely small, an order
of magnitude smaller than the systems biologists classify as
"bacteria", but not smaller than a number of small viruses. Are
these entities bacteria? Biologists do not use the term
"bacteria" loosely, and the defining parameter of bacteria is not
size. For example, there are protozoa, which as a group consists
of organisms considerably more complex structurally and
dynamically than bacteria, that are smaller than certain
bacteria. There are also fungi that are smaller than certain
bacteria. In biology, structure and dynamics are the criteria for
differentiating bacteria, protozoa, fungi, and viruses -- not
size. Biologists, for example, never use the term "microbacteria"
to characterize living systems which are not bacteria but which
are smaller than bacteria. Again, the term "bacteria" puts no
constraint on the size of a system, except that the system must
be at least large enough to contain those molecular entities and
structures that differentiate bacteria from other known living
forms.
     So when several years ago a group of NASA space researchers
announced to the world in a press conference that they had
discovered "nannobacteria" (their first spelling of the term) in
a Martian rock, and that these inclusions were of the order of 20
to 50 nanometers in diameter, a host of biologists rose up to
complain (and even effectively shout) that these inclusions could
not be "bacteria" because they were simply too small as systems
to include the molecular and structural repertoires known to
exist in bacteria, which repertoires differentiate bacteria from
viruses, protozoa, fungi, etc. To provide an analogy that might
be helpful in understanding the uproar among biologists, if a
team of sociologists would call a press conference to announce to
the world that a group of six people holding hands in a closed
loop would thenceforth be called by them a "benzene ring", and
they would further announce their intent to seek the financial
support of various funding agencies for research in chemistry --
given such a scenario, one might understand a few thousand
chemists rising to their feet to shout that a benzene ring is
much more than six entities joined in a closed loop. "Never
mind," the sociologists reply: "We know chemistry when we see
it."
     Considering the use of labels, one wonders whether to label
this affair as out of Harold Pinter or Groucho Marx. Certainly,
at the outset, it would have been advisable to have called the
Martian rock inclusions something other than "nannobacteria".
     Apparently, rather than dissipate, the debate has now become
more structured. A Finnish scientist has now formally requested
the University of Kuopio to investigate the work of one of its
senior researchers, Olavi Kajander, the accuser charging that
Kajander is making misleading but widely publicized claims that
he has discovered a new form of life, known as "nanobacteria".
This has some international ramifications, since Kajander is now
formally associated with the NASA Institute of Astrobiology, a
"virtual institute" involving 11 research centers in the US, and
collaborating with David McKay of the Johnson Space Center in
Texas on Mars rock research (details of the work of both Kajander
and McKay is included in the related background material below).
     In brief, Kajander claims that he has identified DNA in
nanobacteria. Jouni Issakainen (Turku University, FI), the
Finnish scientist (mycologist) who is requesting investigation,
says this cannot be substantiated because controls were not
shown, and because Kajander increased the normal concentration of
a DNA stain by an order of magnitude, as well as increasing the
reaction time. Under these conditions, says Issakainen, the stain
can become nonspecific.
     Kajander, in turn, states: "In fact, I don't care whether
nanobacteria have genetic material or not -- we have shown that
they are automatically replicating particles that produce
apatite, and that they are involved in disease. And I want to
cure disease."
     Apparently despite the controversy, the medical and
scientific sections of the Academy of Finland have continued to
support Kajander's work. Reviewers of a US$120,000 (FM706,000) 3-
year grant application for work on nanobacteria "combining
microbiology, geology, and astrobiology" recommended rejection,
but the grant was approved after the publication of Kajander's
paper in the _Proceedings of the National Academy of Sciences
US_, and evidently funded with money from the Academy's "risk
fund". An academy spokesman states: "Although we recognize that
there are no solid elements of a scientific basis, the academy
decided to take a risk with the work."
-----------
Alison Abbott: Battle lines drawn between "nanobacteria"
researchers.
(Nature 9 Sep 99 401:105)
QY: Alison Abbott: nature@nature.com
-------------------
Summary by SCIENCE-WEEK http://scienceweek.com 8Oct99
For more information: http://scienceweek.com/swfr.htm
-------------------
Related Background:
NANOBACTERIA AND PATHOGENIC EXTRACELLULAR CALCIFICATION
The formation of discrete and organized inorganic crystalline
structures within macromolecular extracellular matrices is a
widespread biological phenomenon generally referred to as
biomineralization. Mammalian bone and dental enamel are examples
of biomineralization involving *apatite minerals, but the
molecular basis of such mineralization remains largely unknown.
Recently, bacteria have been implicated as factors in
biogeochemical cycles for mineral formation in aqueous sediments.
The principle constituent of modern *authigenic phosphate
minerals in marine sediments is carbonate apatite. Microorganisms
are capable of depositing apatite in sea water, and they can
segregate Ca from Mg and actively nucleate carbonate apatite by
means of specific *oligopeptides under conditions of pH < 8.5 and
an Mg/Ca concentration ratio of greater than 0.1. Such conditions
are also present in the human body. ... ... Kajander and
Ciftcioglu (University of Kuopio, FI) report a study of biogenic
apatite production by "nanobacteria", identified by the authors
as "the *smallest cell-walled bacteria, only recently discovered
in human and cow blood and commercial cell culture serum." The
authors report that nanobacteria can act as crystallization
centers for the formation of biogenic apatite structures, and
that nanobacteria can produce apatite in media mimicking tissue
fluids and *glomerular filtrate, and provide a unique model for
in vitro studies of calcification. The authors suggest that
nanobacteria may play a key role in the formation of all kidney
stones, and they report they have found nanobacteria in all 30
human kidney stones that they have screened. The authors suggest
their findings are of concern in medicine because nanobacterial
*bacteremia occurs in humans, and nanobacterial crystallization
centers might initiate pathological calcification.
-----------
QY: E. Olavi Kajander: Olavi.Kajander@uku.fi
(Proc. Natl. Acad. Sci. US 7 Jul 98 95:8274)
(ScienceWeek 7 Aug 98)
-------------------
Related Background:
... ... *apatite minerals: A group of phosphate-containing
minerals. 
... ... *authigenic phosphate minerals: Authigenic minerals
(authigenes) are minerals that came into existence with or after
the formation of the rock of which they constitute a part. The
principal constituent of modern authigenic phosphate minerals in 
marine sediments is carbonate (hydroxy)fluorapatite:
Ca(sub10)(PO(sub4))(sub6-x)(CO(sub3))(subx)(F,OH)(sub2+x).
... ... *oligopeptides: A peptide composed of no more than 10
amino acids.
... ... *smallest cell-walled bacteria: The electron micrographs
in this report show various forms with diameters 0.2 to 0.5
microns. See related reports below concerning the reported size
of nanobacteria.
... ... *glomerular filtrate: A glomerulus is a tuft-like
structure composed of blood vessel capillaries or nerve fibers,
and in this context, a glomerulus is a blood vessel capillary
structure and part of the nephron, the fundamental filtration
unit of the kidney. The filtrate from kidney glomeruli consists
of small solute molecules filtered under pressure from blood.
... ... *bacteremia: This is a general term referring to the
presence of bacteria in blood.
-------------------
Summary & Notes by SCIENCE-WEEK http://scienceweek.com 7Aug98
For more information: http://scienceweek.com/swfr.htm

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5. NEUROBIOLOGY: ON THE HISTORY OF NEUROSCIENCE
Of all the sciences, what is now called "neuroscience" is most
central to the question, What are we? The history of neuroscience
has been long, difficult, and fragmented, but never without a
continuing sense of excitement as new insights and techniques
push forward the research frontier.
... ... E.R. Kandel and L.R. Squire (2 installations, US) present
a review of the history of neuroscience, the authors making the
following points:
     1) The authors point out that during the latter part of the
20th century, the study of the brain moved from a peripheral
position within both the biological and psychological sciences to
become an interdisciplinary field called "neuroscience" that now
occupies a central position within each discipline. This
realignment occurred because the biological study of the brain
became incorporated into a common framework with cell and
molecular biology on the one side and with psychology on the
other side. Within this new framework, the scope of neuroscience
ranges from genes to cognition, from molecules to mind.
     2) Concerning developments in neuroscience during the past
10 years, the authors identify the following important research
advances:
... ... 1990: a) Segi Ogawa et al developed *functional magnetic
resonance imaging. b) Mario Capecchi and Oliver Smythies
developed *gene knockout technology, which was soon applied to
neuroscience.
... ... 1991: a) Linda Buck and Richard Axel discovered that the
olfactory receptor family consists of over 1000 different genes.
b) The anatomical components of the medial temporal lobe memory
system were identified.
... ... 1993: The Huntington's Disease Collaborative Research
Group identified the gene responsible for *Huntington's disease.
... ... 1990s: a) Neural development was transformed from a
descriptive to a molecular discipline by Gerald Fischbach, Jack
McMahan, Tom Jessell, and Corey Goodman. b) Neuroimaging was
applied to problems of human cognition, including perception,
attention, and memory. c) Reinhard Jahn, James Rothman, Richard
Scheffer, and Thomas Sudhof delineate the molecules critical for
*exocytosis.
... ... 1998: The first 3-dimensional structure of an *ion
channel is revealed by Rod MacKinnon.
     3) The authors conclude: "The neuroscience of higher
cognitive processes is only beginning. For neuroscience to
address the most challenging problems confronting the behavioral
and biological sciences, we will need to continue to search for
new molecular and cellular approaches and use them in conjunction
with systems neuroscience and psychological science. In this way
we will best be able to relate molecular events and specific
changes within neural circuits to mental processes such as
perception, memory, thought, and possibly consciousness itself."
-----------
E.R. Kandel and L.R. Squire: Neuroscience: Breaking down
scientific barriers to the study of brain and mind.
(Science 10 Nov 00 290:1113)
QY: Eric R. Kandel, Columbia University 212-854-1754
-----------
Text Notes:
... ... *functional magnetic resonance imaging: (fMRI) We must
first distinguish between magnetic resonance imaging (MRI) and
"functional" magnetic resonance imaging (fMRI) as applied to the
brain. The former is essentially a technique for examining
morphology, while the latter is a technique for examining
activity of brain tissue. Both techniques involve computerized
analysis of data. In general, MRI involves magnetic coils
producing a static magnetic field parallel to the long axis of
the patient or subject, combined with inner concentric magnetic
coils producing a static magnetic field perpendicular to the long
axis. A radio-frequency coil specifically designed for the head
perturbs the static fields to generate a magnetic resonance
image. The interaction physics in this technique is that between
the magnetic fields and atomic nuclei in brain tissue. "Sliced"
views can be obtained from any angle, and the resolution is quite
high and on the order of millimeters for current magnetic field
strengths of 1.5 tesla. Functional magnetic resonance imaging
(fMRI), the variant of MRI discussed here, is based on the fact
that oxyhemoglobin, the oxygen-carrying form of hemoglobin, has a
different magnetic resonance signal than deoxyhemoglobin, the
oxygen-depleted form of hemoglobin. Activated brain areas utilize
more oxygen, which transiently decreases the levels of
oxyhemoglobin and increases the levels of deoxyhemoglobin, and
within seconds the brain microvasculature responds to the local
change by increasing the flow of oxygen-rich blood into the
active area. This local response thus leads to an increase in the
oxyhemoglobin-deoxyhemoglobin ratio, which forms the basis for
the fMRI signal in this technique. Because of its high spatial
resolution (millimeters) and high temporal resolution (seconds)
compared to other imaging techniques, fMRI is now the technology
of choice for studies of the functional architecture of the human
brain.
... ... *gene knockout technology: In general, in this context,
"knockout technology" involves the generation of a mutant
organism (usually a mouse) with a missing specific gene.
... ... *Huntington's disease: (Huntington's chorea) First
described by George Huntington (1850-1916), the disease attacks
specific regions of the brain (e.g., caudate nucleus and
putamen), and leads to insanity and eventual death.
... ... *exocytosis: This refers to the bulk transport of
materials out of the cell across the cell membrane (plasma
membrane). The process generally involves the encasing of the
material within intracellular membranes, forming a "vacuole", and
the subsequent transport of the vacuole to the cell surface. At
the cell surface, the vacuole fuses with the plasma membrane, and
the contents of the vacuole are deposited outside the cell.
Various aspects of the process are visible with both light and
electron microscopy in a variety of cell systems, and this is the
process primarily responsible for excretion and secretion by
individual cells.
... ... *ion channel: Ion channels are protein channels in cell
membranes that allow ions to pass from extracellular solution to
intracellular solution and vice versa. Most ion channels are
selective, allowing only certain ions to pass, and an individual
cell has ion channels with various ion selectivities. From an
electrical standpoint, each ion channel is effectively a specific
parallel conductance pathway through the cell membrane, and the
dynamic electrical behavior of nerve cells is essentially
directly determined by the opening and closing of its ion
channels.
-------------------
Summary & Notes by SCIENCE-WEEK http://scienceweek.com 8Dec00
For more information: http://scienceweek.com/swfr.htm

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6. PHYSIOLOGY: ON INSULIN
     The term "hormone" was first used in 1902 by William Bayliss
(1860-1924) and Ernest Starling (1866-1927) to describe the
action of secretin, a hormone produced by the mammalian *duodenum
and which stimulates the secretion of pancreatic juice. Based
more on physiological effects than on chemical structure,
subsequent use of the term "hormone" led to the definition of
hormones as signal molecules, products of glandular cells, with
the signal molecules secreted into the internal milieu, most
frequently into the blood. Acting on target cells, these chemical
messengers coordinate activities of different parts of the body.
Target cells, in turn, respond according to their degree of
differentiation, age, and functional and nutritional status, the
target cells integrating many hormonal and neuronal regulatory
stimuli. The target cell "receptor" is a specific chemical
structure required for target cells to receive and recognize a
hormone messenger. In general, hormone receptors transduce the
external chemical signals provided by hormones and are
responsible for the initiation of the first cellular responses to
hormones, this first response usually involving a cascade of
specific biochemical reactions inside the cell.
     The disease *diabetes mellitus has a long history, but it
was only in 1869 that Paul Langerhans (1847-1888) identified a
new type of cell in the pancreas, cells apparently glandular in
character, and histological groups of these cells came to be
called "islets of Langerhans". In 1889, von Mering and Minkowski
demonstrated that diabetes mellitus, characterized in its most
evident form by permanent high blood sugar (hyperglycemia) and
glucose in the urine (glycosuria; glucosuria) could be induced
experimentally in the dog by total removal of the pancreas. This
demonstrated the essential role of the pancreas in the regulation
of glucose balance (glucose homeostasis). The hormone responsible
for this action was called "insulin", and was finally isolated
from the pancreas in 1922 by Frederick Banting (1891-1941) and
Charles Best (1899-1978) [*Note #1]. This discovery had an
enormous impact in physiology, biochemistry, and medicine. The
discovery had an extremely beneficial effect on the prognosis and
therapy of insulin-dependent diabetes, allowing a specific
replacement treatment for endogenous insulin deficiency, which if
untreated is potentially fatal. The arrival of the insulin era
was also of major importance in protein chemistry. Insulin was
one of the first proteins to be crystallized (Abel 1926), and its
primary structure was the first to be elucidated (Sanger 1953).
Partial synthesis was accomplished between 1964 and 1966, and
total synthesis was completed in 1974. Human insulin, available
commercially, is currently prepared by a modification of pork
insulin or by a biosynthetic process involving genetic
engineering.   
     The insulin molecule consists of two polypeptide chains
connected by two disulfide bridges, with a third disulfide bridge
linking parts of one chain. This two-chain structure has
evidently been present throughout evolution, but major variations
in the amino acid sequences are observed between species. Various
mammalian insulins usually have similar potencies in all mammals,
including humans; fish insulin has considerable potency in
mammals. It is evidently the 3-dimensional structure of insulin,
and not the primary sequence of amino acid residues, which is
responsible for its potency across different species: variations
in amino acid sequence are still potent, provided the specific 3-
dimensional structure is maintained.
     Insulin apparently exerts its glucose-lowering effects by
stimulating glucose uptake in tissues such as skeletal muscle,
suppressing fatty acid release from fat (adipose) tissue, and
inhibiting production of glucose by the liver. Muscle, liver, and
fat, therefore, are widely viewed as the principal insulin-
sensitive tissues in the body. The brain, in contrast, has
historically been considered insulin-insensitive because its
ability to use glucose does not require insulin. Because of this,
the idea that insulin participates in the central nervous system
control of food intake and body weight was received with
skepticism when it was first proposed more than 20 years ago.
Since then, however, support for this hypothesis has steadily
accumulated, including the demonstration that insulin is
transported across the *blood-brain barrier, that it is effective
in suppressing food intake when given directly into the brain,
and that insulin receptors are concentrated in brain areas
involved in energy homeostasis.
... ... J.C. Bruening et al (10 authors at 3 installations, DE
US) present new evidence concerning insulin signaling in the
brain, the authors making the following points:
     1) The authors point out that insulin receptors and insulin
signaling proteins are widely distributed throughout the central
nervous system. To study the physiological role of insulin
signaling in the brain, the authors created mice with a neuron-
specific disruption of the insulin receptor gene (no-insulin-
receptor knockout mice = NIRKO mice). Inactivation of the insulin
receptor had no effect on brain development or neuronal survival.
     2) The authors report that female NIRKO mice showed
increased food intake, and both male and female mice developed
diet-sensitive obesity with increases in body fat and plasma
*leptin levels, mild insulin resistance, elevated plasma insulin
levels, and *hypertriglyceridemia. NIRKO mice also exhibited
impaired *spermatogenesis and *ovarian follicle maturation
because of *hypothalamic dysregulation of *luteinizing hormone.
The authors conclude: "Thus, insulin receptor signaling in the
central nervous system plays an important role in regulation of
energy disposal, fuel metabolism, and reproduction."
... ... In a commentary on the this work, Michael W. Schwartz
(University of Washington Seattle, US) states: "Bruening and
colleagues provide important evidence to support [the hypothesis
that insulin participates in the central nervous system control
of food intake and body weight]... The stage is now set for
studies to determine if impaired central nervous system signaling
by insulin and leptin contribute to the pathogenesis of two
common metabolic diseases, obesity and *type 2 diabetes."
-----------
J.C. Bruening et al: Role of brain insulin receptor in control of
body weight and reproduction.
(Science 22 Sep 00 289:2122)
QY: Jens C. Bruening: jens.bruening@uni-koeln.de
-----------
Michael W. Schwartz: Staying slim with insulin in mind.
(Science 22 Sep 00 289:2066)
QY: Michael W. Schwartz: mschwart@u.washington.edu
-----------
Text Notes:
... ... *duodenum: The duodenum is the first segment of the
intestine attached to the stomach.
... ... *diabetes mellitus: A metabolic disease in which
carbohydrate utilization is reduced and that of lipid and protein
enhanced, the disease caused by an absolute or relative
deficiency of the hormone insulin. 
... ... *Note #1: For their isolation of insulin, Banting and
MacLeod received the Nobel Prize for Physiology and Medicine in
1923. The human story has been told many times in books and in
film. Briefly, Banting was a scientifically-minded physician
without a laboratory who came to the established physiologist
MacLeod in the early part of 1921 to beg laboratory space to work
on the isolation of insulin. MacLeod tried to discourage Banting,
saying he would not succeed, but finally MacLeod agreed to give
Banting some laboratory space and an assistant, Charles Best.
MacLeod then went off to Europe and did not return until
September 1921, only to find Banting and Best had indeed isolated
insulin. Banting and Best wanted to present their work to the
December 1921 meeting of the American Physiological Society, but
they were unable to do this because neither of them were members
of the Society. MacLeod, who was a member, attached his name to
the paper, and the paper was published under the three names in
1922. When the Nobel Prize was awarded to Banting and MacLeod,
Banting was furious and at first refused to accept the prize. He
finally did accept, but he immediately transferred half the prize
money to Charles Best. MacLeod then gave half _his_ prize money
to James Collip, an assistant who had helped in the later
purification of insulin.
... ... *blood-brain barrier: A selective mechanism opposing the
passage of most ions and large molecular-weight compounds from
the blood to brain tissue, the mechanism operating in a
continuous layer of endothelial cells connected by tight
junctions between cells. (Endothelial cells are flat cells
forming a layer lining blood vessels, lymphatic vessels, the
heart, etc.)
... ... *leptin: First isolated in 1994 by Y. Zhang et al, leptin
is a hormone secreted by fat cells (adipocytes), the hormone
circulating in blood at levels proportionate to fat stores and
acting in the brain to reduce food intake and body weight.
Insulin deficiency in type 1 diabetes does not cause weight gain,
but rather is associated with severe and progressive weight loss.
In contrast, leptin deficiency is associated with severe obesity
syndrome.
... ... *hypertriglyceridemia: Abnormally high concentrations of
triglycerides in blood.
... ... *spermatogenesis: In general, the entire process that
results in the production of sperm cells.
... ... *ovarian follicle: One of the spherical cell aggregations
in the ovary, the aggregation containing an egg cell (ovum).
... ... *hypothalamic: The hypothalamus is a deep brain
structure with various clusters of nerve cells controlling
several important homeostatic functions such as temperature
regulation and food intake, and in addition the sex drive,
aggressive emotions, psychosomatic effects, etc. The
hypothalamus essentially integrates the activity of the
autonomic nervous system, and it acts as an intermediary between
the endocrine (hormone) system and the nervous system, with
various hypothalamic neuron types secreting hormones themselves.
... ... *luteinizing hormone: A hormone produced by the pituitary
gland. Luteinizing hormone has a complex interaction spectrum,
but in general, this hormone stimulates secretion of testosterone
in males, and stimulates secretion of estrogen in females. The
hormone is important both in the production of sperm and in the
production of egg cells.
... ... *type 2 diabetes: Adult-onset diabetes mellitus.
Juvenile-onset diabetes mellitus is type 1 diabetes mellitus.
There are two major forms of diabetes: diabetes mellitus and
diabetes insipidus. When the term "diabetes" is used alone, the
usual referent is diabetes mellitus, which in turn has two types:
juvenile-onset (type 1) and adult-onset (type 2). The various
forms and types of diabetes differ in important ways in both the
physiology and biochemistry of the disease processes. 
-------------------
Summary & Notes by SCIENCE-WEEK http://scienceweek.com 8Dec00
For more information: http://scienceweek.com/swfr.htm

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7. FOCUS REPORTS: ON DARWIN AND HUXLEY
"When Darwin dropped his blockbuster, he did it, as it were, by
remote control. He was an extremely shy man, plagued by bad
health. He had no stomach for getting into the kind of all-out
fight that instinct told him would flare when his theory of
evolution ran headlong into the political and religious orthodoxy
of the day. The Church of England had immense political and
social leverage above and beyond its magisterial control over the
souls of Britain's people. Indeed, Darwin was so reluctant to
confront that juggernaut that for several years he did not
publish his theory at all. He kept on amassing greater and
greater evidence for what his flash of insight, gained years
before in the Galapagos Islands, had told him was true: all
species had evolved. They had been evolving since the beginning
of life. They were related by descent, and those lines of descent
could be traced in fossils. The fossils with which Darwin chose
to back up his theory were as uncontroversial as he could make
them: obscure marine organisms, small barnacles, long-extinct
clams, and so on. Only once in the _Origin of Species_ did he
even hint that evolution had anything to do with people. At the
very end he inserted one sentence: "Light will be thrown on the
origin of man and his history." That was enough, and the fight
was on. Luckily for Darwin, he had an able champion: the
aggressive and imaginative scientist Thomas Henry Huxley. While
Darwin lurked in his home like a timid and anxious turtle, Huxley
was out front, arguing. He took on a distinguished Anglican
bishop in public debate, and demolished him. He even succeeded in
making England's Prime Minister, Benjamin Disraeli, look foolish.
It was Huxley who publicly associated humans with apes. He
pointed out the great range of similarity between man and what he
recognized to be man's closest living relatives, the gorilla and
chimpanzee. From this he reasoned that the three had a common --
and not terribly remote -- ancestor. Since those apes were found
living only in Africa, Huxley suggested that fossils of the joint
ancestor might be found there also."
-----------
D.C. Johanson and M.A. Edey: _Lucy: The Beginnings of Humankind_
(Simon and Schuster, New York 1981, p.27)
[Editor's note: Thomas Henry Huxley (1825-1895) was the
grandfather of the author Aldous Huxley (1894-1963), the Nobel
Prize winner Andrew Huxley (1917- ), and the biologist Julian
Huxley (1887-1975). (The physiologist Hugh Huxley (1924- ) is
unrelated to these other Huxleys.) In 1860, T.H. Huxley took part
in the famous debate with the bishop of Oxford, Samuel
Wilbeforce), at the Oxford meeting of the British Association for
the Advancement of Science. During the discussion, Wilbeforce
asked whether Huxley traced his ancestry to the apes on his
mother's or father's side of the family. Huxley replied that
given the choice of a miserable ape and a man who could make such
a remark at a serious scientific meeting, he would select the
ape. The meeting resulted in a triumph for science.]
-------------------
SCIENCE-WEEK http://scienceweek.com 8Dec00

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8. FROM THE SCIENCEWEEK ARCHIVE:
ON ACCESS TO ESSENTIAL DRUGS IN POOR COUNTRIES
In the last issue of this publication (SW 7 May 99 3:19), we
briefed a report on the current situation concerning the
availability of anti-AIDS drugs in developing countries. A
similar situation exists for a number of other serious epidemic
diseases, in particular for a complex of tropical and other
diseases common in Africa. For more than a century, researchers
in chemistry, biology, and medical science have joined together
in an intensive research effort to combat the deadly diseases
that have ravaged the human species. But it seems that at present
only a small part of the world population, the richer part, is
experiencing the benefits of this effort.
... ... B. Pecoul et al (4 authors at Medicine Without Frontiers
Foundation, FR) present an extensive analysis of the current
problems concerning access to essential drugs in developing
countries, the authors making the following points: 1) At the
present time, entire populations lack access to essential quality
drugs, and the situation appears to be deteriorating. The result
is a further marginalization of much of the world's population.
2) Effective treatment is lacking in poor countries for many
diseases, including *African trypanosomiasis, *Shigella
dysentery, *leishmaniasis, tuberculosis, and *bacterial
meningitis. Treatment may be precluded because no effective drug
exists, the drug is too expensive, or the drug has been withdrawn
from the market. Moreover, research and development in tropical
diseases have come to a near standstill. 3) A serious problem
concerns the local standards for drug production, since many of
the poorer countries do not have the technical, financial, or
human resources required for the application of necessary
standards, and some developed countries may be less strict when
the product being manufactured is designed for export. The
quality of drugs and their effectiveness and safety are less
certain in populations of the poorest people, who are attracted
by lower-priced drugs sold outside pharmacies. Also, both large-
scale and small scale counterfeiting of drugs is a serious
problem. In 1995, for example, during a meningitis epidemic in
Niger that caused 41,000 reported cases of the disease, an
estimated 60,000 persons were inoculated with totally inactive
counterfeit vaccines apparently substituted for the original
vaccines donated by Pasteur Merieux, SmithKline Beecham, and the
neighboring Nigerian government. 3) Drugs necessary for the
treatment of certain tropical diseases have begun to disappear
from the market because they are commercially unprofitable. Many
of these drugs were discovered in the 1950s and 1960s or earlier
and are currently seldom or never used in wealthy countries,
which means a profitable market has ceased to exist. 4) The
prohibitive cost of *antiretroviral drugs for treatment of AIDS
is well known, but there are many other examples of drugs that
are simply not affordable, most of which have been recently
marketed and are still patent-protected. 5) Tuberculosis caused
the deaths of 3 million people in 1997, but the current treatment
regimen is impractical in poor countries and compliance is poor.
At present, people with *multi-drug-resistant tuberculosis in
countries with limited financial resources are not receiving
treatment, "which from a medical and humanitarian perspective is
completely unacceptable." 6) Directors of pharmaceutical
companies in the developed world have stated repeatedly that the
reason for not conducting research on tropical diseases is the
lack of patent protection for innovations in some in some of the
poor countries, which would also explain the limited investments
of the pharmaceutical companies in the countries concerned.
However, with or without patent protection, it is unlikely that
Western manufacturers will devote much of their effort to
financially nonsolvent populations. All things considered, even
if patents are widely enforced, the future of tropical disease
research may not be promising. 7) The authors conclude: "Access
to essential drugs is a basic human right often denied to people
in poor countries. However, it would serve no purpose to demand
new public health or human rights in a manner that would suggest
that such rights will soon become a reality. The current
situation points to the opposite. For a great proportion of the
world, health conditions are worsening, and without fundamental
change in the pharmaceutical market, perspectives [prospects] for
improvement are not encouraging."
-----------
B. Pecoul et al: Access to essential drugs in poor countries.
(J. Amer. Med. Assoc. 27 Jan 99 281:361)
QY: Bernard Pecoul [office@paris.mcf.org]
-----------
Text Notes:
... ... *African trypanosomiasis: (sleeping sickness) Transmitted
by tsetse flies (Glossina). There are two varieties of the
African parasite: Trypanosoma brucei rhodesiense and Trypanosoma
brucei gambiense. American trypanosomiasis is transmitted by
"cone-nosed bugs" (Triatoma, etc.). the American parasite,
labelled Trypanosoma (Schizotrypanum) cruzi, causes Chagas'
disease. Trypanosomes are motile protozoans residing in blood
(hemoflagellates).
... ... *Shigella dysentery: Shigella is a genus of nonmotile
bacteria. The species S. dysenteriae (Shiga bacillus) causes
dysentery in humans and in monkeys.
... ... *leishmaniasis: Infection with Leishmania, a genus of
motile protozoa related to the trypanosomes. Leishmaniasis is a
clinically ill-defined group of diseases, usually divided into 4
types, one of which is kala-azar. Each disease is transmitted by
a sandfly species.
... ... *bacterial meningitis: In general, meningitis is any
inflammation of the membranes (meninges) of the brain or spinal
cord.
... ... *antiretroviral drugs: An "antiretroviral drug" is any
drug acting against retroviruses. Retroviruses are single-
stranded RNA viruses that have an enzyme called reverse
transcriptase, and with this enzyme the viral RNA is used as a
template to produce viral DNA from cellular material. This DNA is
then incorporated into the host cell's genome, where it codes for
the synthesis of viral components. The HIV virus is a retrovirus.
... ... *multi-drug-resistant tuberculosis: Tuberculosis is a
specific disease caused by Mycobacterium tuberculosis, which may
affect almost any tissue or organ of the body, but most commonly
the lungs. A number of drug-resistant strains of M. tuberculosis
have evolved, including some strains that are resistant to all or
nearly all the drugs known to be active against the pathogen.
-------------------
Summary & Notes by SCIENCE-WEEK [http://scienceweek.com] 14May99


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