What is Hematology?

Hematology is an independent branch of medical science that focuses on blood and hematopoietic tissue.

hematology

Overview

The medicine of the motherland has recorded the blood in the book of the Yellow Emperor's Canon, and the name of blood has been mentioned in foreign countries in the 3rd to 4th century BC. However, the understanding of blood composition and function has long been idealistic and incomplete, and some concepts have been inferred from the phenomenon of drips and incomplete observations. The systematic and scientific study of blood began after the advent of the microscope. Microscopic observation of red blood cells (1673), white blood cells (1749), and platelets (1842) in the blood is called the tangible part of the blood. Hematologists Research focus. The body fluid part of the blood, also known as the blood without components (or plasma), has been studied by biochemists and immunologists for many years.

Awareness of blood cells

The discovery of blood cells has a history of 150 to 300 years, but the morphology of these cells is still an important part of hematologist research. With the continuous improvement of the technique of observing blood cells, the precision of optical microscopy has continued to improve. The staining technology has made the cell morphology clearer and easier to identify, and it has been able to distinguish various types of white blood cells and observe the abnormal morphology of various blood cells. The invention of special microscopes has made blood cell shapes The learning concept is more substantial.

(I) Detection of the number of blood cells

This relies on the invention of blood cell pipettes (1852 to 1867), blood cell counting plates (1855), hemoglobin meters (1878 to 1895), and cell separation technology (1877 to 1912). In 1953, the American Coulter invented the world's first automatic blood cell counter. With the development of basic medicine and the application of high science and technology, especially the application of computer technology, the level of blood analyzers has been continuously improved, the detection principle has been continuously improved, and measurements have been made. The parameters are gradually increasing. Fast detection speed, high accuracy, and easy operation are the advantages of blood analyzers. The advent of various types of blood analyzers has continuously provided more useful experimental indicators for clinical use, which is of great significance for the diagnosis and treatment of diseases.

(Two) understanding of red blood cells

The functional understanding of red blood cells first began in 1871 to 1876. It is known that red blood cells have aerobic function and can participate in breathing in tissues. From 1900 to 1930, they have a more comprehensive understanding of this. It was only known in 1935 that carbonic anhydrase was present in red blood cells. It can convert a large amount of carbon dioxide into carbonate ions and dissolve them in the blood. At the same time, it can also convert carbonate ions into carbon dioxide and release them in the alveoli. This discovery not only clarified the respiration of red blood cells, but also learned that red blood cells and blood acid-base balance are closely related. After 1967, it was clear that glyceraldehyde 2,3-bisphosphate in red blood cells can act on deoxygenated hemoglobin molecules, which is beneficial to tissues to obtain more oxygen. In 1946, the life span of red blood cells was definitely about 120 days. Human blood transfusion can be carried out safely after the red blood cell ABO blood type was issued in 1901. In the 1920s, it was known that red blood cells needed glucose for preservation in vitro. In the 1930s, blood stored in vitro was used for transfusion, and blood banks were gradually established in the 1940s. A comprehensive understanding of red blood cell metabolism is after 1959. In the past 50 years, the relationship between red blood cell structure and fat and protein has been relatively clear.

(Three) white blood cell recognition

1. Understanding of granulocytes

From 1892 to 1930, neutrophils were known to have the functions of chemotactic, phagocytosis, and killing bacteria. It was not known until 1986 that the killing of bacteria depends on the peroxidase existing in the cells. The reason for oxidation. Although the function of eosinophils is still not very clear, it has been known since 1949 that eosinophils will transform into Charcot-Leyden crystals. In recent years, it has been known that cationic proteins are found in eosinophils, which can kill tiny organisms. Have some understanding of basophil function. There are many chemical components in the basophilic particles, such as histamine, serotonin, etc. are some substances involved in allergic reactions.

2. Understanding of monocytes

The phagocytic function of monocytes was only reported after 1910. Such cells can not only eat common bacteria, but also special bacteria that are difficult to kill (such as Mycobacterium tuberculosis and leprosy), as well as larger fungi. And single-cell parasites. Therefore, at that time, some people called it "a scavenger sweeping the battlefield." It was discovered after the 1960s that the killing and digestion of phagocytosed substances by monocytes mainly depended on the large number of lysosomes present in monocytes. In recent years, I have learned that monocytes also play a large role in immune function. They can digest foreign substances and present antigens to lymphocytes. At the same time, they can secrete a variety of cytokines to regulate the growth and proliferation of lymphocytes and other blood cells. Or frustrated. In 1924, Aschoff proposed the so-called "reticulo-endothelial system" (RES), which was rejected after 1976 and replaced with the "mononuclear phagocyte system" related to monocytes. , MPS). It is now known that monocytes are just a relatively short-lived cell in the system, which later enters various tissues and becomes tissue cells. Tissue cells are called phagocytes if they have phagocytic substances.

3. Understanding of lymphocytes and plasma cells

The understanding of lymphocyte function is mainly in the last 30 years. Lymphocytes were thought to be the last generation in the lymphatic system, have matured to no longer differentiate, and don't know much about its role. Since 1959, it has been discovered that lymphocytes are stimulated by mitogens and antigens and then transformed into immunoblasts, which can then undergo mitosis and proliferation. In recent years, it has become clearer that although the lymphocytes are similar in shape, they are significantly different in function: B cells produce antibodies; some of the T cells have a killing effect, some have an auxiliary effect, some have an inhibitory effect, and some have an induction effect. Role, etc. In fact, various types of lymphocytes have a more detailed division of labor: a lymphocyte only responds to 1 or 2 antigens, and there are thousands of antigens. You can imagine the complexity of lymphocyte division. As for plasma cells, it is an immunoglobulin-secreting cell transformed by lymphocytes after being stimulated by an antigen, which has been confirmed in the 1960s. T cells can also produce a variety of cytokines.

Thrombosis and hemostasis

Platelets were discovered in 1842, and it was not known until 1882 that it had hemostatic and repairing blood vessel wall functions. In 1923, platelets were known to have aggregation and adhesion functions. Its mechanism of action and ultrastructure have been gradually understood in the past 40 years. It is now known that the aggregation and adhesion functions are affected by many substances in the body, such as epinephrine, thrombin, collagen, prostaglandins, etc .; some of these substances can Platelets are produced inside and secreted out of platelets through microtubules, and then act on platelets. The research progress of platelet ultrastructure has clarified various substructures in platelets, and it is also clear that these substructures are related to the production and secretion of some of the above substances.

With the use of laser confocal microscopy for single platelet tomography to analyze the Ca2 + concentration during single platelet activation, and the use of flow cytometry to observe changes in population platelet Ca2 + flow, it was confirmed that extraplatelet calcium influx plays a major role during platelet activation and is clinical The diagnosis of thrombotic diseases at work and the research of antiplatelet drugs have established an important methodological basis. In recent years, it has also been discovered that platelets can form vesicles in the form of budding or platelet microparticles (PMP) in the form of pseudofoot rupture after being activated. Detection of PMP in the blood circulation can more completely reflect the functions of platelets participating in thrombosis and blood coagulation. P-selectin released after platelets are activated can combine with receptors on the membranes of leukocytes and / or monocytes to form platelet-leukocyte aggregates and / or platelet-monocyte aggregates, which can be used to reflect the specificity of arterial thrombosis. One of the landmarks.

Understanding of hemostasis and thrombosis started with bleeding. For example, hemophilia was recorded in the Jewish code before 2000. After the 1950s, there was an in-depth understanding of the coagulation mechanism. By the 1960s, the "waterfall theory" had become a recognized coagulation mechanism. In the late 1960s, with the discovery of various congenital factor deficiencies or dysfunctions, various components involved in the hemostatic response were identified. In the 1970s, with the advancement of biochemical technology, the understanding of the structure and function of various factors was accelerated, and some new coagulation and fibrinolytic related factors were discovered, such as 2 plasmin inhibitor and protein C, etc. . In the 1980s, research on adhesion molecules such as fibronectin was carried out, and cell molecules such as vascular endothelial cells, blood coagulation, fibrinolytic system, platelets, leukocytes and other coagulation inhibitors were cloned to gradually elucidate the molecular mechanism of hemostasis and thrombosis. . From the 1990s to the present, with the in-depth study of the function and mechanism of tissue factor pathway inhibitors, antithrombin, thrombus and hemostatic molecular markers, etc., the traditional "waterfall theory" has been perfected and modified, and thrombosis and hemostasis have been broadened. Research fields.

The role of blood coagulation, fibrinolysis, endothelial cells and platelets in thrombosis has also been deeply understood at the molecular level. With the development of molecular biology, molecular immunology and other disciplines, a series of methods have been developed and established in the field of thrombosis and hemostasis for the experimental diagnosis of hemorrhagic diseases and the detection of risk factors for thrombotic diseases, as well as anticoagulant thrombolytic therapy. Monitoring. And the detection of molecular markers has become an important method and basis for research and diagnosis of prethrombotic state and thrombosis.

Understanding of bone marrow hepatocytes and hematopoietic regulation

(I) Understanding of hematopoietic hepatocytes

(B) Understanding of bone marrow mesenchymal liver cells

(3) Understanding of Hematopoietic Regulation

Understanding of Hematopoietic and Lymphocytic Tumours

(I) Understanding of Leukemia Stem Cells

(B) classification of hematopoietic and lymphoid tumors ^[1]