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- Cytotoxic
activity of
3,3',4,4',5,5'
-hexahydroxyst
ilbene against
breast cancer
cells is
mediated by
induction of
p53 and
downregulation
of
mitochondrial
superoxide
dismutase: Toxicology in
Vitro, Vol.
22, No. 5.
(August 2008),
pp.
1361-1370.The
phytochemical
resveratrol,
which is found
in grapes and
red wine, has
been reported
to have a
variety of
biological
properties. It
was shown in
our previous
research that
introduction
of additional
hydroxyl
groups into
the stilbene
structure
increases the
biological
activity of
resveratrol.
In this study,
the activity
of
3,3',4,4',5,5'
-hexahydroxyst
ilbene (M8)
was
investigated
in ZR-75-1,
MDA-MB-231 and
T47D human
breast cancer
cells. For
evaluation of
cytotoxic
activity of
M8, clonogenic
and cell
proliferation
assays were
used. The IC50
values
obtained in
the clonogenic
assay were
0.846 [mu]M
for T47D,
8.53 [mu]M for
ZR-75-1 cells
and 25.5 [mu]M
for
MDA-MB-231,
while IC50
values
obtained in
the cell
proliferation
assay were
significantly
higher:
90.1 [mu]M,
98.4 [mu]M,
127.8 [mu]M
for T47D,
ZR-75-1 and
MDA-MB-231
cells,
respectively.
Compound M8
caused the
activation of
caspase-8 in
MDA-MB-231
cells (marker
of extrinsic
apoptotic
pathway),
while
activities of
caspase-9
(marker of
intrinsic
apoptotic
pathway) and
caspase-3 were
increased in
all 3 tested
cell lines.
Activation of
caspase-9 and
caspase-3 was
connected with
loss of
mitochondrial
potential and
increase of
p53, which
could have an
impact on
downregulation
of
mitochondrial
superoxide
dismutase
(MnSOD) seen
in our
experiments.
MnSOD is a key
enzyme
providing
antioxidative
defense in
mitochondria -
the cellular
center of
reactive
oxygen
species'
generation.
Downregulation
of MnSOD can
therefore
cause a
significant
decrease of
antioxidant
defense in
cancer cells.
An increase of
oxidative
stress
conditions was
suggested by
loss of
reduced
glutathione in
tested cells.
Since cancer
cells are
usually under
permanent
oxidative
stress,
additional
increased ROS
generation as
a result of
the
interaction of
M8 with the
mitochondrial
respiratory
chain and a
decrease in
oxidative
defense can
therefore be a
promising
method for
selective
elimination of
cancer cells.
Source: Toxicology in Vitro, Vol. 22, No. 5. (August 2008), pp. 1361-1370. - Environmental
contaminants
in
pathogenesis
of breast
cancer.: Indian journal
of
experimental
biology, Vol.
44, No. 8.
(August 2006),
pp.
597-617.This
review is an
attempt to
comprehend the
diverse groups
of
environmental
chemical
contaminants
with a
potential for
pathogenesis
of breast
cancer, their
probable
sources and
the possible
mechanisms by
which these
environmental
contaminants
act and
interplay with
other risk
factors.
Estrogens are
closely
related to the
pathogenesis
of breast
cancer.
Oxidative
catabolism of
estrogen,
mediated by
various
cytochrome
P450 enzymes,
generates
reactive free
radicals that
can cause
oxidative
damage. The
same enzymes
of estrogenic
metabolic
pathways
catalyze
biological
activation of
several
environmental
(xenobiotic)
chemicals.
Xenobiotic
chemicals may
exert their
pathological
effects
through
generation of
reactive free
radicals.
Breast tissue
can be a
target of
several
xenobiotic
agents.
DNA-reactive
metabolites of
different
xenobiotic
compounds have
been detected
in breast
tissue. Many
phase I and II
xenobiotic
metabolizing
enzymes are
expressed in
both normal
and cancerous
breast
tissues. These
enzymes play a
significant
role in the
activation/det
oxification of
xenobiotic and
endogenous
compounds
including
estrogens.
More than 30
carcinogenic
chemicals are
present in
tobacco smoke;
many of them
are
fat-soluble,
resistant to
metabolism and
can be stored
in breast
adipose
tissue.
Similarly,
pesticides are
also known to
cause
oxidative
stress; while
some act as
endocrine
disruptor,
some are shown
to suppress
apoptosis in
estrogen
sensitive cell
lines. Reports
have shown an
association of
smoking (both
active and
passive) and
pesticides
with breast
cancer risk.
However, the
issues have
remained
controversial.
Different
mutagenic
substances
that are
generated in
the cooking
process e.g.,
heterocyclic
amines and
polycyclic
aromatic
hydrocarbons
(PAHs) can be
a threat to
breast tissue.
PAHs and
dioxins exert
their adverse
effects
through the
aryl
hydrocarbon
receptor
(AhR), which
activates
several genes
involved in
the
metabolisms of
xenobiotic
compounds and
endogenous
estrogens.
These
chemicals also
induce
AhR-dependent
mitochondrial
dysfunction.
Many of the
environmental
pollutants
suppress the
immune system,
which are
implicated to
risk. A better
understanding
about the
biological
effects of
different
environmental
carcinogenic
compounds and
determination
of their
impact on
rising
incidence of
breast cancer
will be
beneficial in
improving
preventive
policy against
breast cancer.
Source: Indian journal of experimental biology, Vol. 44, No. 8. (August 2006), pp. 597-617. - Persuasion
online or on
paper: a new
take on an old
issue: Learning and
Instruction,
Vol. 13, No.
5. (October
2003), pp.
511-532.Few,
if any,
studies have
examined the
persuasion
process as it
unfolds in the
computer
environments
that are so
popular in
today?s
educational
settings. As
such, the
purpose of
this study was
to examine the
extent to
which
students?
knowledge and
beliefs and
their
reactions to
the features
of the
articles would
be
differentially
influenced as
a result of
reading
traditional
persuasive
texts vs.
online
computerized
persuasive
texts. The
results
revealed that
text
presentations
were effective
at
significantly
modifying
both,
students?
knowledge and
beliefs.
However,
students in
the
computerized
text condition
found the
texts
significantly
more difficult
to understand,
less
interesting,
and the
authors less
credible.
Implications
for research
and practice
are forwarded.
Source: Learning and Instruction, Vol. 13, No. 5. (October 2003), pp. 511-532. - Development of
a substitutive
light source
for indoor
daylight
calculations: Building and
Environment,
Vol. 40, No.
12. (December
2005), pp.
1611-1618.The
central focus
of the paper
is to present
the results of
the last 2
years of the
research work
on development
of a
substitutive
light source
for daylight
calculation of
the
illuminance
indoors. In
the paper,
calculation of
spatial
distribution
of daylight
according to
the new CIE
standard is
discussed.
Another focal
topic is the
calculation of
photometric
data of a
light source
which
substitutes
vertical
window or
vertical
window opening
in computer
calculations.
Through the
development of
photometric
data for a
light source,
so that it can
be imported
into
calculation
software, this
software
becomes more
powerful and
useful.
Source: Building and Environment, Vol. 40, No. 12. (December 2005), pp. 1611-1618. - Alternative
scenarios
analysis
concerning
different
types of fuels
used for the
coverage of
the energy
requirements
of a typical
apartment
building in
Thessaloniki,
Greece. Part
II: life cycle
analysis: Building and
Environment,
Vol. 40, No.
12. (December
2005), pp.
1602-1610.This
paper
constitutes a
continuation
of
"Alternative
scenarios
analysis
concerning
different
types of fuels
used for the
coverage of
the energy
requirements
of a typical
apartment
building in
Thessaloniki,
Greece. Part
I: fuel
consumption
and
emissions". It
is concerned
with the
application of
life cycle
analysis (LCA)
methodology to
the model of
the apartment
building
determined in
Part I. The
examination
here includes
emissions of
light heating
oil EL
refining,
transportation
and
combustion, of
natural gas
transportation
and combustion
and of
electricity
generation and
use (lignite,
natural gas,
diesel oil and
kerosene
originated).
All data used
were collected
from a typical
power station
in Greece.
Source: Building and Environment, Vol. 40, No. 12. (December 2005), pp. 1602-1610.
If you would like to find additional social bookmark based links on the topic of Environment we recommend the Open Tag Directory > Environment. If you would like to find related tags we recommend Tag Patterns > Environment.
Environment Tag Pages: 1
Environment Tag Pages: 1
