Platelet Incorporation of Labelled Adenosine and Adenosine Diphosphate

1969 ◽  
Vol 22 (02) ◽  
pp. 304-315 ◽  
Author(s):  
E. W Salzman ◽  
T. P Ashford ◽  
D. A Chambers ◽  
Lena L. Neri
Keyword(s):  
Platelet Rich Plasma ◽  
Adenosine Diphosphate ◽  
Platelet Inhibition ◽  
Electron Microscopic ◽  
Platelet Binding ◽  
Minor Degree ◽  
A Minor ◽  
Plasma Marker ◽  
Electron Microscopic Radioautography ◽  
Simultaneous Assessment

SummaryAfter incubation of platelet-rich plasma with labelled adenosine or ADP, platelet incorporation of radioactivity was assessed. Platelets were rapidly separated for counting by filtration through cellulose acetate Millipore. Inulin-H3 served as a plasma marker, and triple isotope techniques permitted simultaneous assessment of the behavior of the adenine and phosphate moieties of ADP without washing of platelets. In other experiments, electron microscopic radioautography was employed to trace the label after platelet incorporation.The results were consistent with previous reports that ADP is dephosphorylated in plasma and is incorporated by platelets only as a dephosphorylated residue, probably adenosine. The label crossed the platelet membrane and entered the platelet, where it was distributed in platelet granules and the agranular cell sap. Concentration within granules occurred to a minor degree.The results support the hypothesis that platelet aggregation by ADP occurs without a persistent bond of ADP to the platelet. Inhibition of aggregation by adenosine probably depends on a metabolic or transport process rather than on competition between adenosine and ADP for platelet binding sites.

Surfactants Reduce Platelet–Bubble and Platelet–Platelet Binding Induced by In Vitro  Air Embolism

2005 ◽  
Vol 103 (6) ◽  
pp. 1204-1210 ◽  
Author(s):  
David M. Eckmann ◽  
Stephen C. Armstead ◽  
Feras Mardini
Keyword(s):  
Platelet Rich Plasma ◽  
Air Embolism ◽  
Adenosine Diphosphate ◽  
Molecular Probes ◽  
Clinical Role ◽  
Platelet Binding ◽  
Inverted Microscope ◽  
Surface Active ◽  
Surface Active Compounds

Background The effect of gas bubbles on platelet behavior is poorly characterized. The authors assessed platelet-bubble and platelet-platelet binding in platelet-rich plasma in the presence and absence of bubbles and three surface-active compounds. Methods Platelet-rich plasma was prepared from blood drawn from 16 volunteers. Experimental groups were surfactant alone, sparging (microbubble embolization) alone, sparging with surfactant, and neither sparging nor surfactant. The surfactants were Pluronic F-127 (Molecular Probes, Eugene, OR), Perftoran (OJSC SPC Perftoran, Moscow, Russia), and Dow Corning Antifoam 1510US (Dow Corning, Midland, MI). Videomicroscopy images of specimens drawn through rectangular glass microcapillaries on an inverted microscope and Coulter counter measurements were used to assess platelet-bubble and platelet-platelet binding, respectively, in calcium-free and recalcified samples. Histamine-induced and adenosine diphosphate-induced platelet-platelet binding were measured in unsparged samples. Differences between groups were considered significant for P < 0.05 using analysis of variance and the Bonferroni correction. Results Sixty to 100 platelets adhered to bubbles in sparged, surfactant-free samples. With sparging and surfactant, few platelets adhered to bubbles. Numbers of platelet singlets and multimers not adherent to bubbles were different (P < 0.05) compared both with unsparged samples and sparged samples without surfactant. No significant platelet-platelet binding occurred in uncalcified, sparged samples, although 20-30 platelets adhered to bubbles. Without sparging, histamine and adenosine diphosphate provoked platelet-platelet binding with and without surfactants present. Conclusions Sparging causes platelets to bind to air bubbles and each other. Surfactants added before sparging attenuate platelet-bubble and platelet-platelet binding. Surfactants may have a clinical role in attenuating gas embolism-induced platelet-bubble and platelet-platelet binding.

Comparative Ultrastructure of Freeze-Cleaved and Thin-Sectioned Membranes

1969 ◽  
Vol 27 ◽  
pp. 324-325
Author(s):  
Ronald S. Weinstein ◽  
N. Scott McNutt
Keyword(s):  
The Other ◽  
Electron Microscopic ◽  
Thin Sections ◽  
Minor Degree ◽  
Technical Artifacts ◽  
A Minor ◽  
True Structure ◽  
Shed Light ◽  
Comparative Ultrastructure ◽  
Degree Of Overlap

The structure of biomembranes may now be studied at relatively high resolution using two vastly different electron microscopic preparative techniques. One utilizes thin sections of chemically fixed, dehydrated, and plastic embedded tissue while the other, freeze-cleaving, allows for the examination of partially hydrated tissues which are physically fixed by freezing. Each technique introduces certain artifacts, some of which have been investigated and others that are ill-defined. Although there is a minor degree of overlap between the artifacts of the two techniques, most of the artifacts are unique to one technique or the other. Therefore, comparison of the electron microscopic images of membranes produced with the two techniques may shed light on both technical artifacts and on the true structure of membranes. We have carried out comparative studies on a number of different kinds of membranes, two examples of which are briefly described.

A simplified method of emulsion coating and development for quantitative electron microscopic radioautography

1978 ◽  
Vol 36 (2) ◽  
pp. 64-65
Author(s):  
K. Yoshida ◽  
F. Murata ◽  
S. Ohno ◽  
T. Nagata
Keyword(s):  
Mass Production ◽  
Identical Condition ◽  
Microscopic Level ◽  
Electron Microscopic Level ◽  
Electron Microscopic ◽  
Simplified Method ◽  
Complicated Process ◽  
Critical Problems ◽  
Electron Microscopic Radioautography ◽  
Quantitative Radioautography

IntroductionSeveral methods of mounting emulsion for radioautography at the electron microscopic level have been reported. From the viewpoint of quantitative radioautography, however, there are many critical problems in the procedure to produce radioautographs. For example, it is necessary to apply and develop emulsions in several experimental groups under an identical condition. Moreover, it is necessary to treat a lot of grids at the same time in the dark room for statistical analysis. Since the complicated process and technical difficulties in these procedures are inadequate to conduct a quantitative analysis of many radioautographs at once, many factors may bring about unexpected results. In order to improve these complicated procedures, a simplified dropping method for mass production of radioautographs under an identical condition was previously reported. However, this procedure was not completely satisfactory from the viewpoint of emulsion homogeneity. This paper reports another improved procedure employing wire loops.

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.

Platelet Behaviour in Non-Insulin-Dependent Diabetes -Influence of Vascular Complications, Treatment and Metabolic Control

1986 ◽  
Vol 55 (03) ◽  
pp. 361-365 ◽  
Author(s):  
I Peacock ◽  
M Hawkins ◽  
S Heptinstall
Keyword(s):  
Blood Glucose ◽  
Metabolic Control ◽  
Platelet Reactivity ◽  
Platelet Rich Plasma ◽  
Vascular Complications ◽  
Adenosine Diphosphate ◽  
Glycosylated Haemoglobin ◽  
Insulin Dependent Diabetes ◽  
Lipid Levels ◽  
Insulin Dependent

SummaryPlatelet-rich plasma was prepared from 47 patients with noninsulin-dependent diabetes treated with glibenclamide and metformin, and 21 controls. The release of radio-labelled 5-hydroxy-tryptamine in response to aggregating agents (adenosine diphosphate, adrenaline and sodium arachidonate), and the effects on release of a selective thromboxane inhibitor (UK-34787) were investigated. Subsequently, 20 of the diabetic subjects were chosen at random for treatment with insulin; the remainder continued to take tablets. Platelet studies were then repeated, in all patients, after 4 and 6 months.The results showed an association between platelet behaviour and the presence of vascular complications, and were consistent with previous observations of reduced platelet reactivity in patients taking sulphonylureas. There was no correlation of platelet reactivity with blood glucose, glycosylated haemoglobin or lipid levels.

Unique coronary vasodilator induction by leukotriene D4

1985 ◽  
Vol 249 (3) ◽  
pp. H698-H702 ◽  
Author(s):  
D. Ezra ◽  
G. Feuerstein ◽  
J. F. Czaja ◽  
F. R. Laurindo ◽  
C. K. Finton ◽  
...  
Keyword(s):  
Coronary Flow ◽  
Platelet Rich Plasma ◽  
Platelet Activating Factor ◽  
Adenosine Diphosphate ◽  
Coronary Vein ◽  
Marked Rise ◽  
Leukotriene D4 ◽  
Coronary Vasodilator ◽  
Myocardial Area

Coronary blood flow (CBF) and myocardial contractility decrease markedly in response to intracoronary administration of leukotriene D4 (LTD4). With steady infusion, however, both CBF and contractility escape, approaching preinfusion values despite ongoing LTD4 administration. To clarify the mechanism of this escape, we reinfused plasma from the coronary vein draining the myocardial area receiving LTD4. Introducing this plasma into a coronary artery caused a marked rise in coronary flow for the duration of the plasma infusion. Coronary flow reduction with vasopressin or mechanical occlusion matching that caused by LTD4 failed to elicit vasodilator production. Thus a unique coronary vasodilator factor is induced by LTD4. Whole blood or platelet-rich plasma incubated with LTD4 in vitro produced the same pattern of coronary dilation on intracoronary infusion; LTD4 incubation with platelet-poor plasma failed to elicit a vasodilation. The vasodilator factor is stable and is not potassium, a prostaglandin, catecholamine, histamine, serotonin, adenosine, adenosine diphosphate, or platelet-activating factor. Production of this leukotriene-induced vasodilator factor may account for the escape from LTD4-induced coronary constriction.

scholarly journals Electron Microscopic Radioautographic Study on Protein Synthesis in Mitochondria of Binucleate Hepatocytes of Aging Mice

2007 ◽  
Vol 7 ◽  
pp. 1008-1023 ◽  
Author(s):  
Tetsuji Nagata
Keyword(s):  
Protein Synthesis ◽  
Labeling Index ◽  
Electron Microscopic ◽  
Protein Precursor ◽  
Binucleate Cells ◽  
Mouse Hepatocytes ◽  
Electron Microscopic Radioautography ◽  
Liver Tissues

In order to study the aging changes of intramitochondrial protein synthesis in mouse hepatocytes, 10 groups of aging mice, each consisting of three individuals, total 30, from fetal day 19 to postnatal year 2, were injected with3H-leucine, a protein precursor, sacrificed 1 h later, and the liver tissues processed for electron microscopic radioautography. On electron microscopic radioautograms obtained from each animal, the numbers of mitochondria, the numbers of labeled mitochondria, and the mitochondrial labeling index labeled with3H-leucine that showed protein synthesis in each hepatocyte, both mononucleate and binucleate cells, were counted and the averages in respective aging groups were compared. From the results, it was demonstrated that the numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein syntheses in both mononucleate and binucleate hepatocytes of mice at various ages increased due to development of animals. The numbers of mitochondria, the numbers of labeled mitochondria, and the labeling indices of intramitochondrial protein synthesis in binucleate hepatocytes were more than those of mononucleate hepatocytes at the same aging stages.

Isolation of radioactive iodothyronines for kinetic studies: a comparison of two methods

1982 ◽  
Vol 99 (1) ◽  
pp. 64-71 ◽  
Author(s):  
Jens Faber ◽  
lb Bo Lumholtz ◽  
Carsten Kirkegaard ◽  
Kaj Siersbæk-Nielsen ◽  
Thorkild Friis
Keyword(s):  
Radioactive Iodine ◽  
Single Injection ◽  
Kinetic Studies ◽  
Acid Precipitation ◽  
Relative Difference ◽  
Metabolic Clearance ◽  
Metabolic Clearance Rate ◽  
Minor Degree ◽  
A Minor

Abstract. A method based on the principle of gel separation followed by antibody extraction (GSAE) has been developed for isolation of radioactive thyroxine (T4), 3,5,3'-triiodothyronine (T3), 3,3',5'-triiodothyronine (rT3), 3,3'-diiodothyronine (3,3'-T2), 3',5'-diiodothyronine (3',5'-T2) and 3'-monoiodothyronine (3'-T1) in serum. This method was used for the estimation of the metabolic clearance rate (MCR) of the iodothyronines using the single injection, non-compartmental approach, and was compared to the conventional trichloroacetic acid precipitation/ethanol extraction (TCA-E) technique. The GSAE method excluded the co-determination of radioactive iodine and iodoproteins, whereas the co-determination of radiolabelled daughter iodothyronines was found negligible. The relative difference of duplicate estimations of MCR was approximately 10%. Using the TCA-E method for isolation of tracer, the MCR of T4, T3 and rT3 was underestimated to a minor degree (20%), whereas the MCRs of 3,3'-T2, 3',5'-T2 and 3'-T1 were 20–40% of those estimated by the GSAE method. In conclusion the GSAE method was found suitable for kinetic studies of iodothyronines, whereas the TCA-E method cannot be used for turnover studies of 3,3'-T2, 3',5'-T2 or 3'-T1.

scholarly journals Fibrinogen competes with von Willebrand factor for binding to the glycoprotein IIb/IIIa complex when platelets are stimulated with thrombin

Blood ◽  
1984 ◽  
Vol 64 (4) ◽  
pp. 797-800 ◽  
Author(s):  
HR Gralnick ◽  
SB Williams ◽  
BS Coller
Keyword(s):  
Monoclonal Antibodies ◽  
Von Willebrand Factor ◽  
Adenosine Diphosphate ◽  
Glycoprotein Ib ◽  
Human Fibrinogen ◽  
Factor Binding ◽  
Normal Plasma ◽  
Platelet Binding ◽  
Von Willebrand ◽  
Willebrand Factor

Two monoclonal antibodies--one that blocks ristocetin-induced platelet binding of von Willebrand factor to glycoprotein Ib and one that blocks adenosine diphosphate-induced binding of fibrinogen to the glycoprotein IIb/IIIa complex--were used to assess the binding site(s) for von Willebrand factor when platelets are stimulated with thrombin or adenosine diphosphate (ADP). Neither agonist induced binding of von Willebrand factor to glycoprotein Ib. ADP and thrombin induced von Willebrand factor binding exclusively to the glycoprotein IIb/IIIa complex. The results of the site of binding of von Willebrand factor with thrombasthenic platelets were consistent with the data obtained with the monoclonal antibodies and normal platelets. Human fibrinogen caused complete inhibition of thrombin-induced von Willebrand factor binding to normal platelets at concentrations considerably below that found in normal plasma. We conclude that thrombin induces very little binding of exogenous von Willebrand factor to platelets at normal plasma fibrinogen levels.

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