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Kinetics of ADP-induced platelet aggregation
Vol. 70, Suppl.
s59
ABSTRACTS OF 12TH NATIONAL CONGRESS
1
c 109 KINETICS
OF ADP-INDUCED
PLATELET
Landolfi.
Centro
Fisiopatologia
Universita
Ricerche
Cattolica,
Largo Gemelli
Transmittance evaluation
and
of platelet
formation
impedance
rate
of
occurrence
the
free
platelets
the kinetic
of
this
last
incubated
at
platelets
counts,
after
were
ADP addition,
glutaraldehyde. followed
In all
the
were 7.66i0.85
unchanged. with
This
consistent
platelet
there
under basal
velocities
which allows parameters,
Medica,
for
aggregation. at
conditions
the
free
a standard
error
a very
aggregometer.
platelet
%, respectively.
of the first interesting
the
events tool
0.05
%
concentration
of platelet
while
intervals
with
< 7 %. In 8 normal
of p (85.3+2.4%)
the evaluation
to evaluate
were performed
as at 2 set
suspension
and the percentage and 96.6t3.59
an Elvi
as well
the
, the
by follouing
in order
Experiments
rpm in
vitrot’
conditions
quantitated
the
set
is
1000
conditions
“in
more complex than
approach
of
(v)
per
kinetic “in
far
fixation
was a reduction
method,
aggregation
after
experimental
x103
& R.
Semeiotica
commonly used
by events
We used this
platelet
decay with
platelets
De Cristofaro di
Under the comnon experimental
37’ C and stirred
a single-exponential
pM) ADP concentrations
variations, generated
phenomenon is more directly
performed
at 4 jM ADP, the aggregation (p)
are
of ADP-induced
Electronic
R.
Istituto
00168 Roma, Italy.
in the suspension.
on PRP samples free
8,
bridges.
decay
parameters
dell’Emostasi,
signal
aggregation,
of platelet-platelet
B_ Rocca.
AGGREGATION.
for
subjects,
recruitment At
lower
v values
(1
were
of aggregation investigating
vitro”.
Cl10 DIFFERENTIAL EFFECT OF MODIFIED LDL ON THE EXPRESSION OF PROCOAGULANT ACTIVITY BY MONOCYTES AND ENDOTHELIAL CELLS. p. Madema, E. Stragliotto, S. Colli, M. Camera, F. Bernini and E. Tremoli. E. Grossi Paoletti Center, Institute of Pharmacological Sciences, University of Milan, Italy. Monocyte/macrophages are one of the first cells involved in the pathogenesis of atherosclerosis. Evidence in literature indicates that monocyte/macrophages have a limited number of classical LDL receptors, but express the so called “scavenger” receptors for modified lipoproteins, i.e. acetyl-LDL and oxidized-LDL. In this study, the effects of native and chemically modified LDL on the expression of procoagulant activity (PCA) by human monocytes and human umbilical vein endothelial cells in colture were evaluated. Human monocytes were isolated from the mononuclear cell fraction after adhesion to plastic dishes. Cells were incubated with different concentrations of native and modified LDL (25-200 ug protein/ml) for 6 and 24 hours. The expression of PCA was determined using the one stage clotting assay. Native and oxidized LDL significantly inhibited the expression of PCA by monocytes, the effect being comparable after 6 and 24 hours incubation. On the contrary acetyl-LDL stimulated the basal expression of PCA with a maximal effect obtained using 50 ug protein/ml. Similar effects were observed also when the expression of PCA was evaluated in monocytes coincubated with platelets.The observed effects are cell-dependent since native and acetyl LDL did not inflence the expression of PCA by endothelial cells. At odds to what observed in monocytes, oxidized LDL concentration-dependently stimulated the expression of PCA by endothelial cells. All together these data suggest that native and modified LDL affect PCA expression and that their behaviour is dependent upon the cell considered. In addition, the observation that acet I-LDL are capable to stimulate PCA expreselan by menacytee auggeet a rele far ti le atberegeflle llpegreteins in increasing the potential of this cell to localize fibrin.
s59
ABSTRACTS OF 12TH NATIONAL CONGRESS
1
c 109 KINETICS
OF ADP-INDUCED
PLATELET
Landolfi.
Centro
Fisiopatologia
Universita
Ricerche
Cattolica,
Largo Gemelli
Transmittance evaluation
and
of platelet
formation
impedance
rate
of
occurrence
the
free
platelets
the kinetic
of
this
last
incubated
at
platelets
counts,
after
were
ADP addition,
glutaraldehyde. followed
In all
the
were 7.66i0.85
unchanged. with
This
consistent
platelet
there
under basal
velocities
which allows parameters,
Medica,
for
aggregation. at
conditions
the
free
a standard
error
a very
aggregometer.
platelet
%, respectively.
of the first interesting
the
events tool
0.05
%
concentration
of platelet
while
intervals
with
< 7 %. In 8 normal
of p (85.3+2.4%)
the evaluation
to evaluate
were performed
as at 2 set
suspension
and the percentage and 96.6t3.59
an Elvi
as well
the
, the
by follouing
in order
Experiments
rpm in
vitrot’
conditions
quantitated
the
set
is
1000
conditions
“in
more complex than
approach
of
(v)
per
kinetic “in
far
fixation
was a reduction
method,
aggregation
after
experimental
x103
& R.
Semeiotica
commonly used
by events
We used this
platelet
decay with
platelets
De Cristofaro di
Under the comnon experimental
37’ C and stirred
a single-exponential
pM) ADP concentrations
variations, generated
phenomenon is more directly
performed
at 4 jM ADP, the aggregation (p)
are
of ADP-induced
Electronic
R.
Istituto
00168 Roma, Italy.
in the suspension.
on PRP samples free
8,
bridges.
decay
parameters
dell’Emostasi,
signal
aggregation,
of platelet-platelet
B_ Rocca.
AGGREGATION.
for
subjects,
recruitment At
lower
v values
(1
were
of aggregation investigating
vitro”.
Cl10 DIFFERENTIAL EFFECT OF MODIFIED LDL ON THE EXPRESSION OF PROCOAGULANT ACTIVITY BY MONOCYTES AND ENDOTHELIAL CELLS. p. Madema, E. Stragliotto, S. Colli, M. Camera, F. Bernini and E. Tremoli. E. Grossi Paoletti Center, Institute of Pharmacological Sciences, University of Milan, Italy. Monocyte/macrophages are one of the first cells involved in the pathogenesis of atherosclerosis. Evidence in literature indicates that monocyte/macrophages have a limited number of classical LDL receptors, but express the so called “scavenger” receptors for modified lipoproteins, i.e. acetyl-LDL and oxidized-LDL. In this study, the effects of native and chemically modified LDL on the expression of procoagulant activity (PCA) by human monocytes and human umbilical vein endothelial cells in colture were evaluated. Human monocytes were isolated from the mononuclear cell fraction after adhesion to plastic dishes. Cells were incubated with different concentrations of native and modified LDL (25-200 ug protein/ml) for 6 and 24 hours. The expression of PCA was determined using the one stage clotting assay. Native and oxidized LDL significantly inhibited the expression of PCA by monocytes, the effect being comparable after 6 and 24 hours incubation. On the contrary acetyl-LDL stimulated the basal expression of PCA with a maximal effect obtained using 50 ug protein/ml. Similar effects were observed also when the expression of PCA was evaluated in monocytes coincubated with platelets.The observed effects are cell-dependent since native and acetyl LDL did not inflence the expression of PCA by endothelial cells. At odds to what observed in monocytes, oxidized LDL concentration-dependently stimulated the expression of PCA by endothelial cells. All together these data suggest that native and modified LDL affect PCA expression and that their behaviour is dependent upon the cell considered. In addition, the observation that acet I-LDL are capable to stimulate PCA expreselan by menacytee auggeet a rele far ti le atberegeflle llpegreteins in increasing the potential of this cell to localize fibrin.