Experimental Venous Thrombosis in the Rat

Summary

1. The effect of erythremia and thrombocythemia on thrombus formation has been examined in rats using a standardized operation on the jugular vein. In control animals the incidence of thrombosis was 30’% ( ± 4.6 S. E.).

2. Hypoxic induced erythremia increased the incidence of thrombosis (53% — p <C 0.05). The mean hematocrit value in this group was 62.

3. An increase in the thrombocyte count with 34%, produced by giving a thermostable human plasma fraction to normal rats, did not significantly increase the incidence of thrombosis (40%).

4. An increase in the thrombocyte count with 26% in erythremic animals increased the incidence of thrombosis nearly twice (56%, p <C 0.05).

5. The global tests for plasma coagulation, the fibrinogen levels and the antifibrinolytic activity of plasma were not significantly influenced by the conditions examined.

6. The number of adhesive platelets measured in vitro increased in the animals with erythremia.

^* Supported by the Norwegian Council on Cardiovascular Diseases.

• References

• 1 Abildgaard C, Cornet J, Johnson H, Fort E, Shulman S. Stimulation of thrombopoiesis in rats by injection of human plasma extracts. Blood 20: 770-771 1962;
• 2 Ashwin J. G, Jaques L. B. The effect of phosphorus³², dextran, reserpine and strypturon on the thrombus formation in rats. Thrombos. Diathes. haemorrh. (Stuttg) 05: 543-552 1961;
• 3 Björkman S. E, Laurell C. B, Nilsson I. M. Serum proteins and fibrinolysis in polycythemia vera. Scand. J. clin. Lab. Invest. 08: 304-308 1956;
• 4 Blake O. R, Ashwin J. G, Jaques L. B. An assay for the antithrombotic activity of anticoagulants. J. clin. Path. 12: 118-122 1959;
• 5 Blombäck B, Blombäck M. Purification of human and bovine fibrinogen. Ark. Kemi. 10: 415 1956;
• 6 Brecher G, Cronkite E. P. Morphology and enumeration of human blood platelets. J. appl. Physiol. 03: 365-377 1950;
• 7 Burch G. E, De Pasquale N. P. Editorial. Hematocrit, blood viscosity and myocardial infarction. Amer. J. Med. 32: 161-163 1962;
• 8 Chievitz E, Thiede T. Complications and causes of death in polycythemia vera. Acta med. scand. 172: 513-523 1962;
• 9 Egeberg O. Assay of antihemophilic A, B and C factors by one-stage cephalin systems. Scand. J. clin. Lab. Invest. 13: 140-152 1961;
• 10 Gaarder A. M, Jonsen J, Laland S, Hellem A, Owren P. A. Adenosine diphosphate in red cells as a factor in the adhesiveness of human blood platelets. Nature 192: 531-532 1961;
• 11 Godal H. C. Simple syneresis procedure for fibrinogen assay. Scand. T. clin. Lab- Invest. 13: 530 1961;
• 12 Gullon A. C, Richardson T. Q. Effect of hematocrit on venous return. Circulation 09: 157-164 1961;
• 13 Hellem A. J. The adhesiveness of human blood platelets in vitro. Oslo University Press; Norway: 1960
• 14 Hellem A. J. C, Borchgrevink F, Ames S. B. The role of red cells in haemostasis: The relation between haematocrit, bleeding time and platelet adhesiveness. Brit. J. Haemat. 07: 42-50 1961;
• 15 Hjort P, Rapaport S. I, Owren P. A. A simple, specific one-stage prothrombin assay using Russell’s viper venom in cephalin suspension. J. Lab. clin. Med. 46: 89-97 1955;
• 16 Jacobsson, Studies on the determination of fibrinogen in human blood plasma. Scan. J. clin. Lab. Invest. 07 suppl. 14 1955;
• 17 Lawrence J. H. Polycythemia. Physiology, Diagnosis and Treatment, Grune and Stratton; New York: 1955
• 18 Linman J. W, Pierre R. V. Thrombocytosis-promoting activity of normal human plasma. Proc. Soc. exp. Biol. 110: 463-466 1962;
• 19 Mendlowitz M. The effect of anemia and polycythemia on digital intravascular blood viscosity. J. clin. Invest. 27: 565-571 1948;
• 20 Mustard J. F, Murphy E. A, Roswell H. C, Downie H. G. Factors influencing thrombus formation in vivo. Amer. J. Med. 33: 621-647 1962;
• 21 Nordöy A. Experimental venous thrombosis in the rat. Thrombos. Diathes. haemorrh. (Stuttg) 09: 427-435 1963;
• 22 Nordöy A, Ödegaard A. E. The influence of citrate and heparin on the adhesiveness of rat platelets and human platelets measured in vitro. Scand. J. clin. Lab. Invest. in press 1963
• 23 Norman I. L, Allen E. V. The vascular complications of polycythemia. Amer. Heart J. 13: 257-274 1937;
• 24 Nygaard K. K. A direct method of counting platelets in oxalated plasma. Proc. Mayo Clin. 08: 365-370 1933;
• 25 Owren P. A. The coagulation of blood. Investigation on a new clotting factor. Acta med. scand. 128 suppl. 194 1947;
• 26 Owren P. A, Aas K. The control of dicumarol therapy and the quantitative determination of prothrombin and proconvertin. Scand. J. clin. Lab. Invest. 03: 201-208 1951;
• 27 Shulman S, Currimbhoy Z, Fort E, Alcade Y. Platelet-stimulating properties of human plasma, with observations on the role of the spleen and the pathogenesis and treatment of idiopathic thrombocytopenic purpura. Amer. J. Dis. Child. 100: 747-748 1960;
• 28 Stecher G, Wolfers H, Nettesheim P. Polycythemia vera. Dtsch. med. Wschr. 39-40 1861-1867, 1899-1904 1961;
• 29 Waaler B. A. Contact activation in the intrinsic blood clotting system. Thesis. Scand. J. clin. Lab. Invest. Ã1: suppl. 37 1959
• 30 Wells Jr. R. E, Merill E. W. Shear rate dependence on the viscosity of whole blood and plasma. Science 133: 767 1961;
• 31 Whittaker S. R. F, Winton F. R. The apparent viscosity of blood flowing in the isolated hind limb of the dog and its variation with corpuscular concentration. J. Physiol. 78: 339-358 1933;