Experimental Modification of the Platelet Release Reaction Induced by Collagen

1975 ◽  
Author(s):  
J. L. Gordon ◽  
D. E. Maclntyre ◽  
A. H. Drummond
Keyword(s):  
Storage Temperature ◽  
Platelet Rich Plasma ◽  
Release Kinetics ◽  
Experimental Conditions ◽  
Pharmacological Agents ◽  
Release Reaction ◽  
Significant Release ◽  
Collagen Suspension ◽  
Reaction Profile ◽  
Experimental Modification

Collagen-induced release of platelet constituents can be divided into two kinetically-distinct phases, only one of which is associated with platelet aggregation, and the aggregation-independent release is less susceptible to inhibition by pharmacological agents (Drummond and Gordon, 1974). Minor variations in experimental conditions alter the release reaction profile. Collagen was incubated with platelet rich plasma (PRP) for one minute at 37°, under conditions in which no aggregation occurred ( + 3nM EDTA or in absence of stirring). The reaction was ‘terminated’ by addition of ice-cold EDTA-saline and samples were then centrifuged (14,800 g) under the conditions described in the table.No significant release was detected under any of the above conditions if saline were substituted for collagen suspension.These results indicate that the storage temperature and time after centrifugation are as important as the centrifugation conditions themselves, and suggest reasons for discrepancies reported in previous studies of collagen induced release kinetics.Drummond, A. H. and Gordon, J. L. (1974). Brit. J. Pharmacol. 52, 130 P.

Storage of Human Blood Platelets

1974 ◽  
Vol 32 (02/03) ◽  
pp. 405-416 ◽  
Author(s):  
M. R Hardeman ◽  
Carina J L. Heynens
Keyword(s):  
Storage Temperature ◽  
Platelet Rich Plasma ◽  
Blood Platelets ◽  
Storage Period ◽  
Serotonin Uptake ◽  
Hypotonic Shock ◽  
Glycolytic Intermediates

SummaryStorage experiments were performed at 4°, 25° and 37° C with platelet-rich plasma under sterile conditions. In some experiments also the effect of storing platelets at 4° C in whole blood was investigated.Before, during and after three days of storage, the platelets were tested at 37° C for their serotonin uptake and response to hypotonic shock. In addition some glycolytic intermediates were determined.A fair correlation was noticed between the serotonin uptake and hypotonic shock experiments. Both parameters were best maintained at 25° C. Also platelet counting, performed after the storage period, indicated 25° C as the best storage temperature. Determination of glycolytic intermediates did not justify any conclusion regarding the optimal storage temperature. Of the various anticoagulants studied, ACD and heparin gave the best results as to the serotonin uptake and hypotonic shock response, either with fresh or stored platelets. The use of EDTA resulted in the lowest activity, especially after storage.The results of these storage experiments in vitro, correspond well with those in vivo reported in the literature.

Haemostatic Platelet Plug Formation in the Isolated Rabbit Mesenteric Preparation - An Analysis of Red Blood Cell Participation

1980 ◽  
Vol 44 (01) ◽  
pp. 006-008 ◽  
Author(s):  
D Bergqvist ◽  
K-E Arfors
Keyword(s):  
Whole Blood ◽  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
In Vitro Test ◽  
Pharmacological Agents ◽  
Vitro Test ◽  
Releasing Effect ◽  
Plug Formation

SummaryIn a model using an isolated rabbit mesenteric preparation microvessels were transected and the time until haemostatic plugs formed was registered. Perfusion of platelet rich plasma gave no haemostasis whereas whole blood did. Addition of chlorpromazine or adenosine to the whole blood significantly prolonged the time for haemostasis, and addition of ADP to the platelet rich plasma significantly shortened it. It is concluded that red cells are necessary for a normal haemostasis in this model, probably by a combination of a haemodynamic and ADP releasing effect.The fundamental role of platelets in haemostatic plug formation is unquestionable but there are still problems concerning the stimulus for this process to start. Three platelet aggregating substances have been discussed – thrombin, adenosine diphosphate (ADP) and collagen. Evidence speaking in favour of thrombin is, however, very minimal, and the discussion has to be focused on collagen and ADP. In an in vitro system using polyethylene tubings we have shown that "haemostasis" can be obtained without the presence of collagen but against these results can be argued that it is only another in vitro test for platelet aggregation (1).To be able to induce haemostasis in this model, however, the presence of red blood cells is necessary. To further study this problem we have developed a model where haemostatic plug formation can be studied in the isolated rabbit mesentery and we have briefly reported on this (2).Thus, it is possible to perfuse the vessels with whole blood as well as with platelet rich plasma (PRP) and different pharmacological agents of importance.

Effect of Aspirin on the Thrombelastogram of Human Blood

1973 ◽  
Vol 30 (03) ◽  
pp. 494-498 ◽  
Author(s):  
G de Gaetano ◽  
J Vermylen
Keyword(s):  
Oral Dose ◽  
Single Oral Dose ◽  
Platelet Function ◽  
Human Blood ◽  
Platelet Rich Plasma ◽  
Plasma Samples ◽  
Release Reaction ◽  
Platelet Release

SummaryThrombelastograms of both native blood and re-calcified platelet-rich plasma samples taken from subjects given a single oral dose of aspirin (1 gram) were not significantly different from the pretreatment recordings. Aspirin also did not modify the thrombelastogram when preincubated in vitro with platelet-rich plasma at concentrations inhibiting the platelet “release reaction” by collagen. Thrombelastography therefore cannot evaluate the effect of aspirin on platelet function.

Superoxide, Xanthine Oxidase and Platelet Reactions: Further Studies on Mechanisms by which Oxidants Influence Platelets

1981 ◽  
Vol 45 (03) ◽  
pp. 290-293 ◽  
Author(s):  
Peter H Levine ◽  
Danielle G Sladdin ◽  
Norman I Krinsky
Keyword(s):  
Superoxide Dismutase ◽  
Cytochrome C ◽  
Xanthine Oxidase ◽  
Direct Effect ◽  
Platelet Function ◽  
Experimental Conditions ◽  
Release Reaction

SummaryIn the course of studying the effects on platelets of the oxidant species superoxide (O- 2), Of was generated by the interaction of xanthine oxidase plus xanthine. Surprisingly, gel-filtered platelets, when exposed to xanthine oxidase in the absence of xanthine substrate, were found to generate superoxide (O- 2), as determined by the reduction of added cytochrome c and by the inhibition of this reduction in the presence of superoxide dismutase.In addition to generating Of, the xanthine oxidase-treated platelets display both aggregation and evidence of the release reaction. This xanthine oxidase induced aggreagtion is not inhibited by the addition of either superoxide dismutase or cytochrome c, suggesting that it is due to either a further metabolite of O- 2, or that O- 2 itself exerts no important direct effect on platelet function under these experimental conditions. The ability of Of to modulate platelet reactions in vivo or in vitro remains in doubt, and xanthine oxidase is an unsuitable source of O- 2 in platelet studies because of its own effects on platelets.

scholarly journals Physiological Parameters to Identify Suitable Blood Donor Cows for Preparation of Platelet Rich Plasma

Animals ◽  
2021 ◽  
Vol 11 (8) ◽  
pp. 2296
Author(s):  
Anna Lange-Consiglio ◽  
Rosangela Garlappi ◽  
Chiara Spelta ◽  
Antonella Idda ◽  
Stefano Comazzi ◽  
...  
Keyword(s):  
Blood Donor ◽  
Blood Donors ◽  
Platelet Rich Plasma ◽  
Bovine Mastitis ◽  
Field Conditions ◽  
Blood Collection ◽  
Experimental Conditions ◽  
Acute Mastitis ◽  
Donor Cows ◽  
The Ideal

Platelet rich plasma (PRP) has been shown to be beneficial in the treatment of bovine mastitis, with an action comparable to that of antibiotics. Autologous treatment is feasible in experimental conditions but is difficult to apply in field conditions, particularly in acute mastitis. The ideal scenario would be to have heterologous PRP stored on every farm so that it is readily available when needed. In this paper, we analysed data collected during bovine mastitis treatment with heterologous PRP produced by casual donor cows on several farms. We tried to identify parameters which might be useful to identify the most suitable cows to be used as blood donors, to obtain the highest yield of PRP. Variables considered for each animal were the age, the parity, the date of the last parturition, the season of blood collection, the site of blood collection (jugular or mammary vein) and the reproductive status e.g., pregnant or not pregnant. There were statistically significant differences for all the variables considered from the 135 blood cows, except for the blood collection season. The highest yield of PRP was associated with nonpregnancy blood collection within three months of parturition, parity 3 or 4, and blood collection from the mammary vein.

scholarly journals Chemotactic and Angiogenic Potential of Mineralized Collagen Scaffolds Functionalized with Naturally Occurring Bioactive Factor Mixtures to Stimulate Bone Regeneration

2021 ◽  
Vol 22 (11) ◽  
pp. 5836
Author(s):  
Henriette Bretschneider ◽  
Mandy Quade ◽  
Anja Lode ◽  
Michael Gelinsky ◽  
Stefan Rammelt ◽  
...  
Keyword(s):  
Bone Marrow ◽  
Platelet Rich Plasma ◽  
Umbilical Vein ◽  
Release Kinetics ◽  
Human Bone ◽  
Human Bone Marrow ◽  
Collagen Scaffolds ◽  
Angiogenic Potential ◽  
Naturally Occurring ◽  
Mineralized Collagen

To develop cost-effective and efficient bone substitutes for improved regeneration of bone defects, heparin-modified mineralized collagen scaffolds were functionalized with concentrated, naturally occurring bioactive factor mixtures derived from adipose tissue, platelet-rich plasma and conditioned medium from a hypoxia-treated human bone marrow-derived mesenchymal stem cell line. Besides the analysis of the release kinetics of functionalized scaffolds, the bioactivity of the released bioactive factors was tested with regard to chemotaxis and angiogenic tube formation. Additionally, functionalized scaffolds were seeded with human bone marrow-derived mesenchymal stromal cells (hBM-MSC) and their osteogenic and angiogenic potential was investigated. The release of bioactive factors from the scaffolds was highest within the first 3 days. Bioactivity of the released factors could be confirmed for all bioactive factor mixtures by successful chemoattraction of hBM-MSC in a transwell assay as well as by the formation of prevascular structures in a 2D co-culture system of hBM-MSC and human umbilical vein endothelial cells. The cells seeded directly onto the functionalized scaffolds were able to express osteogenic markers and form tubular networks. In conclusion, heparin-modified mineralized collagen scaffolds could be successfully functionalized with naturally occurring bioactive factor mixtures promoting cell migration and vascularization.

Formation of sarcomeres in developing myotubes: role of mechanical stretch and contractile activation

2000 ◽  
Vol 279 (6) ◽  
pp. C1801-C1811 ◽  
Author(s):  
Patrick G. De Deyne
Keyword(s):  
Electrical Stimulation ◽  
Structural Alignment ◽  
Major Change ◽  
Mechanical Stretch ◽  
Experimental Conditions ◽  
Pharmacological Agents ◽  
Cultured Myotubes ◽  
Contractile Activation ◽  
Sarcomere Assembly ◽  
Passive Stretch

In a series of experiments, cultured myotubes were exposed to passive stretch or pharmacological agents that block contractile activation. Under these experimental conditions, the formation of Z lines and A bands (morphological structures, resulting from the specific structural alignment of sarcomeric proteins, necessary for contraction) was assessed by immunofluorescence. The addition of an antagonist of the voltage-gated Na+ channels [tetrodotoxin (TTX)] for 2 days in developing rat myotube cultures led to a nearly total absence of Z lines and A bands. When contractile activation was allowed to resume for 2 days, the Z lines and A bands reappeared in a significant way. The appearance of Z lines or A bands could not be inhibited nor facilitated by the application of a uniaxial passive stretch. Electrical stimulation of the cultures increased sarcomere assembly significantly. Antagonists of L-type Ca2+ channels (verapamil, nifedipine) combined with electrical stimulation led to the absence of Z lines and A bands to the same degree as the TTX treatment. Western blot analysis did not show a major change in the amount of sarcomeric α-actinin nor a shift in myosin heavy chain phenotype as a result of a 2-day passive stretch or TTX treatment. Results of experiments suggest that temporal Ca2+ transients play an important factor in the assembly and maintenance of sarcomeric structures during muscle fiber development.

scholarly journals Evaluation of platelet-rich plasma gel as an angiogenesis-inducing agent in canineadvancement skin flaps

2020 ◽  
Vol 40 (6) ◽  
pp. 474-478
Author(s):  
Grazielle A.S. Aleixo ◽  
Maria C.O.C. Coelho ◽  
Telga L.A. Almeida ◽  
Márcia F. Pereira ◽  
Miriam N. Teixeira ◽  
...  
Keyword(s):  
Blood Vessel ◽  
Skin Color ◽  
Platelet Rich Plasma ◽  
Skin Flap ◽  
Skin Flaps ◽  
Experimental Conditions ◽  
Significant Difference ◽  
Experimental Group ◽  
Prp Gel ◽  
Made In

ABSTRACT: This work aimed to evaluate the effect of platelet-rich plasma (PRP) on advancement skin flaps in dogs regarding improvement of vascularization, with focus on increasing its viable area, since there are reports that it is a potential angiogenesis stimulator. The experimental group was composed of eight adult bitches, in which two advancement skin flaps were made in the ventral abdominal region. No product was applied in the control flap (CF), while PRP was used in the contralateral flap, called treated flap (TF). The areas were clinically evaluated every two days until the 7th postoperative day regarding skin color and presence of necrosis. At 10 days, both flaps were removed and submitted to histological examination and blood vessel morphometry. The vessels counted in each group were statistically analyzed by the F-test at 1% probability. Results showed no significant difference in macroscopic changes in the wound, or CF and TF vascularization, thus suggesting that PRP gel did not improve advancement skin flap angiogenesis in bitches under the experimental conditions in which this research was developed.

scholarly journals Activation of human platelets by immune complexes prepared with cationized human IgG

Blood ◽  
1993 ◽  
Vol 82 (10) ◽  
pp. 3045-3051
Author(s):  
M Schattner ◽  
M Lazzari ◽  
AS Trevani ◽  
E Malchiodi ◽  
AC Kempfer ◽  
...  
Keyword(s):  
Platelet Aggregation ◽  
Platelet Activation ◽  
Immune Complexes ◽  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Human Igg ◽  
Experimental Conditions ◽  
Induce Platelet Aggregation ◽  
Soluble Immune Complexes ◽  
High Concentrations

The present study shows that the ability of soluble immune complexes (IC), prepared with human IgG and rabbit IgG antibodies against human IgG, to trigger platelet activation was markedly higher for IC prepared with cationized human IgG (catIC) compared with those prepared with untreated human IgG (cIC). CatIC induced platelet aggregation and adenosine triphosphate release in washed platelets (WP), gel-filtered platelets (GFP), or platelet-rich plasma (PRP) at physiologic concentrations of platelets (3 x 10(8)/mL) and at low concentrations of catIC (1 to 30 micrograms/mL). On the contrary, under similar experimental conditions, cIC did not induce aggregation in PRP, WP, or GFP. Low aggregation responses were only observed using high concentrations of both WP (9 x 10(8)/mL) and cIC (500 micrograms/mL). Interestingly, catIC were also able to induce platelet activation under nonaggregating conditions, as evidenced by P-selectin expression. Cationized human IgG alone did not induce platelet aggregation in PRP but triggered either WP or GFP aggregation. However, the concentration needed to induce these responses, was about eightfold higher than those required for catIC. The responses induced either by catIC or cationized human IgG were completely inhibited by treatment with heparin, dextran sulphate, EDTA, prostaglandin E1, or IV3, a monoclonal antibody against the receptor II for the Fc portion of IgG (Fc gamma RII). The data presented in this study suggest that IgG charge constitutes a critical property that conditions the ability of IC to trigger platelet activation.

The platelet strip. I. A low-fibrin contractile model of thrombin-activated platelets

1985 ◽  
Vol 249 (3) ◽  
pp. C279-C287 ◽  
Author(s):  
L. Salganicoff ◽  
M. H. Loughnane ◽  
R. W. Sevy ◽  
M. Russo
Keyword(s):  
Platelet Rich Plasma ◽  
Human Platelets ◽  
Pharmacological Agents ◽  
Nylon Mesh ◽  
Giant Platelet ◽  
Activated Platelets ◽  
Full Relaxation ◽  
Platelet Aggregate ◽  
Thrombin Activation ◽  
Isometric Forces

The ultrastructure and contractile behavior of a new preparation of thrombin-activated human platelets is described. The preparation is referred to as the "platelet strip" because of its similarities to classical vascular smooth muscle strips. The platelet strip consists of a giant platelet aggregate 10 mm long, 4 mm wide, and 200 micron thick. To facilitate handling, the aggregate has a special high-compliance nylon mesh embedded in its mass. Each strip contains 7.3 X 10(8) platelets. Fibrin contamination is 150-fold lower than in platelet-rich plasma clots. Active isometric forces of up to 100 g/cm2 and 6-10 h viability are easily and reproducibly obtained. Platelet strips remain contracted after thrombin activation. The contraction is tonic and partial. Further small increases in force can be produced by depolarizing solutions or pharmacological agents, e.g., ADP, epinephrine, and endoperoxide analogues. These small increases are reversible on washout of the agents. Full relaxation is induced by agents such as prostaglandin E1 or papaverine, which increase adenosine 3',5'-cyclic monophosphate. However, after washout of these agents, recovery of tension is variable depending on the concentration of the drug and the degree of prestretching of the preparation.

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