Date of Award

1960

Document Type

Thesis

Degree Name

Master of Science (MS)

Department

Anatomy

College

College of Graduate Studies

First Advisor

Melvin H. Knisely

Second Advisor

ElsieTaber

Third Advisor

William M. McCord

Abstract

This investigation was an attempt to ascertain the effects of various physical factors on the formation and dissolution of various thrombi in the living animal. The main method consisted of crushing living veins in the mesenteries of the small intestines of frogs and rats and, with horizontally aimed microscopes: 1. Watching the formation of precipitous, sticky coatings on blood cells and blood cell masses. 2. Observing the building of intravascular material into easily detectable thrombi. 3. Studying the various phenomena occurring in the thrombi and in the adjacent blood streams. 4. Observing the eventual disintegration of most of the fresh thrombi. The word thrombus, introduced over 100 years ago by Virchow (1846), has come to be defined in most modern medical dictionaries (Blakiston, Dorland, and Stedman) as a coagulum of the blood formed in situ during life, partially or completely obstructing a blood vessel or cavity of the heart. Welch (1920) more broadly defined a thrombus as a solid mass or plug formed in situ within living blood vessels or the heart from constituents of the blood. As this paper will show, thrombus formation may be much more complicated than simple clotting of the blood. The word embolus, also introduced in its present connotation by Virchow (1846), is defined as a semi-solid blood clot or some other foreign substance carried within flowing blood streams from the point where it is formed to some other position in the vascular system where it either partially or completely obstructs blood flow. One of the great medical problems today is that of thrombosis and its sequelae. DeBakey (1954), whc has studied thrombosis for years and also has reviewed the literature carefully, points out that we do not have precise knowledge of how thrombi form, and further, that in spite or the use of drugs such as heparin, dicoumarol, fibrinolysin, streptokinase, and trypsin in recent years, there is no agreement that thrombosis is decreasing. Thrombi can and do develop under a variety of clinical conditions such as: (1) Following surgical operations. (2) After traumatic or infected childbirth. (3) A complication or various diseases. (Carlotti, Hardy, Linton and White, 1947, showed that the incidence of pulmonary embolism is greater in medical patients than in surgical patients.") (4) Mechanical trauma of different kinds (fractures, crushes, burns, etc.). Some of these clinical conditions can and do kill humans. Since direct investigations of thrombus formation and dissolution are rare, most of our present concepts of thrombosis are based on guesses (Welch and Faxon, 1941). Although hundreds of studies have been undertaken on thrombosis and allied problems, we have not yet learned whether all thrombi are formed by identical methods, or exactly how any one thrombus is formed. We will cite observations made in the living animal and in non-living tissues, and give known explanations as well as theoretical discussions of the phenomena observed. Finally, we will suggest new areas of exploration in this important part of circulatory pathology.

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