scholarly journals Effects of collagen and of aspirin on the concentration of guanosine 3′:5′-cyclic monophosphate in human blood platelets: measurement by a prelabelling technique (Short Communication)

1974 ◽  
Vol 138 (2) ◽  
pp. 317-320 ◽  
Author(s):  
R. J. Haslam ◽  
M. D. McClenaghan
Keyword(s):  
Human Blood ◽  
Cyclic Gmp ◽  
Short Communication ◽  
Blood Platelets ◽  
Release Reaction ◽  
Cyclic Monophosphate ◽  
Platelet Release ◽  
Human Blood Platelets

A method is described for isolating cyclic [3H]GMP from platelets preincubated with [3H]guanine. Collagen increased and aspirin decreased the cyclic [3H]GMP concentration in platelets. The results are consistent with a role for cyclic GMP in the platelet release reaction.

scholarly journals Short communication: possible association of newly absorbed serotonin with nonmetabolic, granule-located adenine nucleotides in human blood platelets

Blood ◽  
1975 ◽  
Vol 45 (3) ◽  
pp. 413-416
Author(s):  
H Holmsen ◽  
CA Setkowsky ◽  
HJ Day
Keyword(s):  
Guinea Pig ◽  
Human Blood ◽  
Short Communication ◽  
Adenine Nucleotides ◽  
Blood Platelets ◽  
Human Platelets ◽  
Serotonin Release ◽  
Release Reaction ◽  
Human Blood Platelets

[3H]-adenine-labeled human platelets in plasma were incubated with or without nonradioactive serotonin. Release reaction was then induced by ADP, epinephrine, collagen, or thrombin. Platelets that had been incubated with serotonin released four times as much serotonin as platelets incubated without serotonin. The specific radioactivities of the ATP and ADP released to plasma during release reaction induced with all four inducers were the same in both systems. This shows that when serotonin is taken up by human platelets, it enters the compartment containing nonmetabolic, granula-stored ATP, and not the compartment with metabolic extragranular ATP. These results suggest that the mechanism of serotonin storage in human platelets is similar to that in other species investigated, i.e., rabbit, guinea pig, and pig.

Short communication: possible association of newly absorbed serotonin with nonmetabolic, granule-located adenine nucleotides in human blood platelets

Blood ◽  
1975 ◽  
Vol 45 (3) ◽  
pp. 413-416 ◽  
Author(s):  
H Holmsen ◽  
CA Setkowsky ◽  
HJ Day
Keyword(s):  
Guinea Pig ◽  
Human Blood ◽  
Short Communication ◽  
Adenine Nucleotides ◽  
Blood Platelets ◽  
Human Platelets ◽  
Serotonin Release ◽  
Release Reaction ◽  
Human Blood Platelets

Abstract [3H]-adenine-labeled human platelets in plasma were incubated with or without nonradioactive serotonin. Release reaction was then induced by ADP, epinephrine, collagen, or thrombin. Platelets that had been incubated with serotonin released four times as much serotonin as platelets incubated without serotonin. The specific radioactivities of the ATP and ADP released to plasma during release reaction induced with all four inducers were the same in both systems. This shows that when serotonin is taken up by human platelets, it enters the compartment containing nonmetabolic, granula-stored ATP, and not the compartment with metabolic extragranular ATP. These results suggest that the mechanism of serotonin storage in human platelets is similar to that in other species investigated, i.e., rabbit, guinea pig, and pig.

On the Mechanism by which Cell Contact Induces the Release Reaction of Blood Platelets; the Effect of Cationic Polymers

1972 ◽  
Vol 27 (01) ◽  
pp. 121-133 ◽  
Author(s):  
P Massini ◽  
E. F Lüscher
Keyword(s):  
Human Blood ◽  
Calcium Ions ◽  
Blood Platelets ◽  
Cell Contact ◽  
Second Phase ◽  
Cationic Polymers ◽  
Release Reaction ◽  
Per Se ◽  
Human Blood Platelets

SummaryHuman blood platelets are aggregated by the basic polymers polylysine and DEAE- dextran. Under certain conditions a second phase of aggregation, concomitant with the release reaction, is elicited. The presence of ADP, calcium ions and a plasmatic cofactor within the primary aggregates are necessary for the induction of the release reaction. These experiments demonstrate that cell contact per se does not lead to a release reaction ; in order to become effective it must take place in the presence of ADP.

scholarly journals Survival and recovery of human platelets stored for five days in a non- plasma medium

Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 672-675 ◽  
Author(s):  
GA Adams ◽  
SD Swenson ◽  
G Rock
Keyword(s):  
Platelet Aggregation ◽  
Human Blood ◽  
Blood Platelets ◽  
Human Platelets ◽  
Plasma Medium ◽  
Release Reaction ◽  
In Vivo Recovery ◽  
Human Blood Platelets

Abstract Human blood platelets were stored for five days as concentrates in 60 mL of: (a) plasma; (b) non-plasma medium with anticoagulant; and (c) non-plasma medium without anticoagulant. All preparations were equally functional when tested for platelet aggregation and release reaction in response to single agonist or synergistic pairs of agonists in vitro. Platelets stored in non-plasma medium with anti-coagulant had lower kallikrein, fibrino(gen)peptide A, lactate, and beta-thromboglobulin than did plasma controls after five days. In vivo recovery and survival of platelets stored in non-plasma medium with anticoagulant were 51.2% +/- 4.3% and 8.7 +/- 0.3 days, respectively, which were not statistically different from plasma controls of 39.2% +/- 4.9% and 7.2 +/- 0.8 days, respectively. It is concluded that platelets can be stored for five days in a non-plasma medium and still have good in vivo recoveries and survivals.

Effects of Aggregating Agents, Cytochalasin B (CB) and Neuraminidase (N) on the Ultrastructure of Freeze Dried (FD) Human blood Platelets

1975 ◽  
Author(s):  
R. B. Davis
Keyword(s):  
Human Blood ◽  
Plasma Membranes ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Adenosine Diphosphate ◽  
Surface Complexes ◽  
Release Reaction ◽  
Cryoprotective Agents ◽  
Freeze Dried ◽  
Human Blood Platelets

Frozen and freeze dried human blood platelets remain intact morphologically when preserved by cryoprotective agents. These studies have investigated effects of 1) the release reaction, 2) discoid stabilization by CB, and 3) N on platelet morphology in FD specimens. Platelets were collected in 1/10 volume of acid citrate and platelet rich plasma (PRP) obtained by centrifugation. Aggregating agents (adenosine diphosphate, 2 × 10-6 M, epinephrine, 5 × 10-5 M, collagen, 30 μg/ml, thrombin 0.2 U/ml) CB (25 μg/ml), trypsin (3 mgs/ml), and N (20 U/ml), then cryoprotective agents, were added. Platelets were FD and the ultrastructure examined. Aggregating agents were associated with 1 ) the appearance of amorphous electron dense material within platelets extending via channels to the exterior; 2) membranous complexes contiguous to plasma membranes; 3) numerous organelles adjacent to the plasma membrane. Platelets in artificial thrombi also showed homogeneous electron opaque areas and membrane rich surface complexes. CB caused vacuolization and previously reported concentric membranous structures were noted in trypsinized platelets. N did not prevent interplatelet bridging. In conclusion, aggregated FD platelets differ from platelets fixed by traditional means, providing morphologic support that platelet organelles and membrane systems relate structurally to the platelet exterior as well as the canalicular system to provide a catalytic lipoprotein surface during the release reaction.

scholarly journals Survival and recovery of human platelets stored for five days in a non- plasma medium

Blood ◽  
1986 ◽  
Vol 67 (3) ◽  
pp. 672-675 ◽  
Author(s):  
GA Adams ◽  
SD Swenson ◽  
G Rock
Keyword(s):  
Platelet Aggregation ◽  
Human Blood ◽  
Blood Platelets ◽  
Human Platelets ◽  
Plasma Medium ◽  
Release Reaction ◽  
In Vivo Recovery ◽  
Human Blood Platelets

Human blood platelets were stored for five days as concentrates in 60 mL of: (a) plasma; (b) non-plasma medium with anticoagulant; and (c) non-plasma medium without anticoagulant. All preparations were equally functional when tested for platelet aggregation and release reaction in response to single agonist or synergistic pairs of agonists in vitro. Platelets stored in non-plasma medium with anti-coagulant had lower kallikrein, fibrino(gen)peptide A, lactate, and beta-thromboglobulin than did plasma controls after five days. In vivo recovery and survival of platelets stored in non-plasma medium with anticoagulant were 51.2% +/- 4.3% and 8.7 +/- 0.3 days, respectively, which were not statistically different from plasma controls of 39.2% +/- 4.9% and 7.2 +/- 0.8 days, respectively. It is concluded that platelets can be stored for five days in a non-plasma medium and still have good in vivo recoveries and survivals.

scholarly journals Phospholipase A1 of human blood platelets (Short Communication)

1973 ◽  
Vol 131 (3) ◽  
pp. 615-618 ◽  
Author(s):  
J. B. Smith ◽  
M. J. Silver ◽  
G. R. Webster
Keyword(s):  
Rapid Method ◽  
Human Blood ◽  
Short Communication ◽  
Blood Platelets ◽  
Phospholipase Activity ◽  
Phospholipase A1 ◽  
Ph Optimum ◽  
Full Activity ◽  
Human Blood Platelets

Substantial phospholipase A1 activity has been demonstrated in human blood platelets, and a rapid method for its measurement is described. The enzyme requires taurocholate for full activity and in these conditions the pH optimum is 4.8. The phospholipase activity is released from platelets by incubation with thrombin.

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