A new dual-label technique for platelet survival studies with the use of111indium and114mindium tropolonate

SummaryTo determine the effect on platelet behavior of transient exposure of platelets to ascorbic acid, studies of platelet function and ultrastructure were done before exposure to ascorbic acid at pH 6.5, during exposure to pH 6.5, and after restoration of pH to pre-acidifìcation levels. The effect of ascorbic acid (A. A.) was compared to that of HCl and citric acid (C. A.). ADP- and collagen-induced aggregation of normal platelets were significantly impaired by both A. A. and C. A. but were less affected by HCl. The release of 14C-serotonin was significantly reduced by each agent. The ultra-structure of normal platelets brought to pH 6.5 by A.A. was normal. After neutralization, there was marked dilatation of the open channel system and loss of the disc shape. When platelets were brought to pH 6.5 by A. A., then neutralized, the aggregates which formed after stimulation by ADP or collagen were smaller than normal, the platelets were less closely approximated, and degranulation was less complete. The data show that exposure of platelets to ascorbic acid for short intervals impairs their function when measured after restoration of pH to levels compatible with maximal responses. Platelet survival studies using autologous platelets labelled with 51Cr in the presence or absence of ascorbic acid showed that the recovery of normal platelets was unaffected by ascorbic acid, whereas recovery of platelets from patients with idiopathic thrombocytopenic purpura, idiopathic thrombocythemia, and alcohol-related thrombocytopenia was markedly reduced. The injury resulting from the use of ascorbic acid in preparing platelets for studies of platelet survival in patients with disorders affecting platelets may impair the recovery of the cells, resulting in artifactual changes in the survival studies.

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Platelet survival studies. An overview of the factors affecting the efficiency and reliability of platelet radiolabeling

Transfusion ◽

10.1046/j.1537-2995.1986.26186124023.x ◽

1986 ◽

Vol 26 (1) ◽

pp. 19-22 ◽

Cited By ~ 6

Author(s):

JG Kelton

Keyword(s):

Factors Affecting ◽

Platelet Survival ◽

Survival Studies ◽

Efficiency And Reliability

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In Vivo Quantification and Platelet Survival Studies: What is the Best Approach?

Radiolabeled Cellular Blood Elements ◽

10.1007/978-1-4684-4922-8_8 ◽

1985 ◽

pp. 135-153 ◽

Cited By ~ 1

Author(s):

A. P. du Heyns

Keyword(s):

Platelet Survival ◽

Survival Studies

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A Dual-label Technique for the Immunohistochemical Demonstration of T-Lymphocyte Subsets in Formalin-fixed, Paraffin-Embedded Rat Lymphoid Tissue

Toxicologic Pathology ◽

10.1177/0192623308322311 ◽

2008 ◽

Vol 36 (6) ◽

pp. 795-804 ◽

Cited By ~ 8

Author(s):

Kevin J. Randall ◽

Gail Pearse

Keyword(s):

T Lymphocyte ◽

Lymphoid Tissue ◽

Lymphocyte Subsets ◽

T Lymphocyte Subsets ◽

Label Technique ◽

Immunohistochemical Demonstration ◽

Formalin Fixed Paraffin ◽

Formalin Fixed Paraffin Embedded ◽

Dual Label ◽

Formalin Fixed

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75SE-Methionine Platelet Survival Studies: a Proposal for a Mathematical Correction of the Curve

Pathophysiology of Haemostasis and Thrombosis ◽

10.1159/000214648 ◽

1982 ◽

Vol 11 (2) ◽

pp. 102-108

Author(s):

Fabrizio Fabris ◽

Alessandra Casonato ◽

Maria Luigia Randi ◽

Lucia Varotto ◽

Cesare Scandellari ◽

...

Keyword(s):

Platelet Survival ◽

Survival Studies

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The uptake of 3H-labelled monodeoxyfluoro-myo-inositols into thymocytes and their incorporation into phospholipid in permeabilized cells

Biochemical Journal ◽

10.1042/bj2910553 ◽

1993 ◽

Vol 291 (2) ◽

pp. 553-560 ◽

Cited By ~ 8

Author(s):

J Offer ◽

J C Metcalfe ◽

G A Smith

Keyword(s):

Cellular Responses ◽

Effective Inhibitor ◽

Permeabilized Cells ◽

Label Technique ◽

Competitive Inhibitors ◽

Phosphatidylinositol Synthase ◽

Potential Inhibitors ◽

Dual Label ◽

Inositol Uptake

Monodeoxyfluoro-myo-inositols were applied to electropermeabilized and intact thymocyte preparations to study their metabolism and uptake in order to investigate their suitability as potential inhibitors of phosphoinositide-mediated cellular responses. Only three of the monodeoxyfluoro-myo-inositols were incorporated into the phospholipids of thymocytes: 1D-3-deoxy-3-fluoro-myo-inositol, 5-deoxy-5-fluoro-myo-inositol and 1D-6-deoxy-6-fluoro-myo-inositol, all of which were weaker substrates for phosphatidylinositol synthase than was myo-inositol. The 3-, 5- and 6-fluoro analogues also behaved as competitive inhibitors, with K1 values of 350 +/- 5 microM, 350 +/- 5 microM and 2.9 +/- 2 mM respectively, compared with a Km for myo-inositol of 31 +/- 4 microM. When incubated with electropermeabilized thymocyte preparations, these three analogues of myo-inositol all formed phospholipids with chromatographic properties which corresponded to those of substituted phosphatidylinositol and phosphatidylinositol monophosphate. The uptake of myo-inositol and of the monodeoxyfluoro-myo-inositols into intact thymocytes was studied by a dual-label technique. All the monodeoxyfluoro-myo-inositols were taken up to some extent, but only 2-deoxy-2-fluoro-myo-inositol and 1D-3-deoxy-3-fluoro-myo-inositol were actively concentrated. The monodeoxyfluoro-myo-inositols were also assayed for their ability to inhibit the uptake of myo-inositol into cells. Both 2-deoxy-2-fluoro-myo-inositol and 1D-3-deoxy-3-fluoro-myo-inositol were effective inhibitors of myo-inositol uptake. Furthermore, 1D-1-deoxy-1-fluoro-myo-inositol, which was not taken up actively, was an effective inhibitor of myo-inositol uptake. The three effective inhibitors all showed Ki values of approximately 150 microM, close to the apparent Km for inositol uptake of 180 microM, and the 4-, 5- and 6-fluoro analogues had Ki values in excess of 10 mM.

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