Studies on Human Platelets

Summary

Human platelets have been separated into 4 more homogeneous populations (A, B, C, and D; D population of highest density) by isopycnic density gradient centrifugation. Newly formed platelets have been identified in band C. These newly formed platelets age in vivo and shift into band D containing mature and old platelets. Newly formed platelets are more active in their ability to incorporate labeled amino acids into protein than mature and/or older platelets. The maturation of newly formed platelets (shift from band C to band D) is concurrent with a gradual loss in their ability to synthesize protein, a increase in density and decrease in size. In addition, newly formed platelets have a lower content of thrombosthenin than do mature (old) platelets.

^* This work was supported in part by grants from the National Institutes of Health (HE-07565), the Chicago and Illinois Heart Associations, and the General Research Support Grant (FR-05477).

• References

• 1 Allen E. H, Schweet R. S. Synthesis of hemoglobin in a cell-free system. I. Properties of the complete system. J. biol. Chem 237: 760 1962;
• 2 Bettex-Galland M, Lüscher E. F. Thrombosthenin - a contractile protein from thrombocytes. Its extraction from human blood platelets and some of its properties. Biochim. biophys. Acta (Amst) 49: 536 1961;
• 3 Booyse F. M, Hoveke T. P, Rafelson Jr M. E. Studies on human platelets. II. Protein synthetic activity of various platelet populations. Biochim. biophys. Acta (Amst) 157: 660 1968;
• 4 Booyse F. M, Hohn D. G, Rafelson Jr. M. E. Studies on human platelets. VI. Study of platelet abnormalities by density gradient separation of platelet populations. S. Afri. med. J 43: 964 1969;
• 5 Booyse F. M, Rafelson Jr. M. E. Protein synthesis and platelet function. In: Dynamics of thrombus formation and dissolution. 149 Johnson S. A, Guest M. (Eds.). J. B. Lippen- cott and Co; Philadelphia: 1969
• 6 Booyse F. M, Zschocke D, Rafelson Jr. M. E. Microquantitation of thrombosthenin in human platelets. Its possible relationship to bleeding abnormalities. J. Lab. clin. Med. (In Press.)
• 7 Booyse F. M, Rafelson Jr. M. E. In vitro incorporation of amino acids into the contractile protein of human blood platelets. Nature (Lond) 215: 283 1967;
• 8 Booyse F. M, Rafelson Jr. M. E. Studies on human platelet. I. Synthesis of platelet protein in a cell-free system. Biochim. biophys. Acta (Amst) 166: 689 1968;
• 9 Booyse F. M, Rafelson Jr. M. E. Human platelet contractile protein. Location, properties, and function. Ser. Haemat 04 (01) 152 1971;
• 10 Booyse F. M, Rafelson Jr. M. E. A contractile protein model for platelet aggregation. Blood 33: 100 1969;
• 11 Booyse F. M, Rafelson Jr. M. E. Stable messenger RNA in the synthesis of contractile protein in human platelets. Biochim. biophys. Acta (Amst) 145: 188 1967;
• 12 Ingram M, Goopersmith A. Reticulated platelets following acute blood loss. Brit. J. Haemat 17: 225 1969;
• 13 Itzhaki R. F, Gill D. M. A micro-biuret method for estimating proteins. Anal. Biochemistry 09: 401 1964;
• 14 Karpatkin S. Heterogeneity of human platelets. I. Metabolic and kinetic evidence suggestive of young and old platelets. J. clin. Invest 48: 1073 1969;
• 15 Mancini G. A, Garbonara A. O, Heremans J. F. Immunochemical quantitation of antigens by single radial immunodiffusion. Immunochemistry 02: 235 1965;
• 16 McDonald T. P, Odell Jr. T. T, Gosslee D. G. Platelet size in relation to platelet age. Proc. Soc. exp. Biol. (N. Y) 115: 684 1964;
• 17 Minter N, Ingram M. Density distribution of platelets. (Abstract). Blood 30: 551 1967;
• 18 Minter F. M. Frequency distribution of platelet densities and platelet volumes. M. S, Thesis, University of Rochester, School of Medicine and Dentistry, Rochester; New York: 1967
• 19 Schulman I, Pierce M, Lukens A, Currimbhoy Z. Studies on thrombopoiesis. I. A factor in normal human plasma required for platelet production; chronic thrombocytopenia due to its deficiency. Blood 16: 943 1960;
• 20 Shulman N. R, Watkins S. P, Itscoitz S. B, Students A. B. Evidence that the spleen retains the youngest and hemostatically most effective platelets. Trans. Ass. Amer. Phycns 81: 302 1968;
• 21 Steiner M, Baldini M. Protein synthesis in aging blood platelets. Blood 33: 628 1969;
• 22 Steiner M. Platelet protein synthesis studied in a cell-free system. Experientia (Basel) 26: 786 1970;
• 23 Webber A. M, Firkin B. G. Two populations of platelets. Nature (Lond) 205: 1332 1965;