(1) Autopsy
Pathological autopsy is one of the basic research methods of pathology. Autopsy can not only directly observe the pathological changes of diseases, so as to make clear the diagnosis of diseases, find out the cause of death, contribute to clinical discussion, verify whether diagnosis and treatment are correct and appropriate, sum up experience, improve the quality of clinical work, but also find and diagnose some infectious diseases, endemic diseases and epidemics in time, and provide basis for prevention and control measures. At the same time, we can also accumulate human pathological data of common and frequently-occurring diseases through a large number of autopsies. Obviously, autopsy is an extremely important method and means to study diseases, and human pathological materials are the most valuable materials to study diseases.
The autopsy rate of a country can often reflect the degree of its civilization and progress. The autopsy rate in many civilized and advanced countries in the world has reached more than 90%, and some countries have made explicit provisions on autopsy in their laws. The autopsy rate in China is still very low, which is not conducive to the development of pathology and medicine in China and needs to be improved urgently.
(2) Biopsy
Through local excision, clamp, needle aspiration, curettage, removal and other surgical methods, pathological examination is carried out to confirm the diagnosis, which is called biopsy. This is a widely used examination and diagnosis method. The advantage of this method is that the tissue is fresh, and the true image of the lesion can be basically maintained, which is beneficial to the study of histology, histochemistry, cytochemistry, ultrastructure and tissue culture. For clinical work, this examination method is helpful for timely and accurate diagnosis of diseases and judgment of curative effect. Especially for unknown tumors and other diseases, accurate and timely diagnosis is of great significance to treatment and prognosis.
(3) Animal experiments
Using the method of animal experiments, we can reproduce some models of human diseases in suitable animals, so that researchers can observe and study them in any way as needed. For example, we can take samples in stages to understand the occurrence and development of diseases or a pathological process. In addition, animal experiments can also be used to study the etiology and pathogenesis of some diseases, as well as the efficacy and influence of drugs or other factors on diseases. The advantage of this method is that it can make up for the limitations and shortcomings of human observation, but after all, there are various differences between animals and humans, so it should be noted that the results of animal experiments cannot be directly applied to humans.
(4) tissue culture and cell culture
A certain tissue or single cell is cultured in vitro with suitable culture medium to observe the occurrence and development of cell and tissue diseases, such as tumor growth, cell canceration, virus replication, chromosome variation and so on. In addition, external factors such as radiation and drugs can be applied to it to observe its influence on cells and tissues. The advantage of this method is that it is convenient to observe and study the process of various diseases or lesions in vitro, and to study the methods affecting them. Moreover, it is one of the good research methods because of its short period and quick effect, which can save research time. However, the disadvantage is that the isolated in vitro environment is different from the overall environment in vivo, and all parts are interrelated and influence each other, so the research results cannot be regarded as the same as the in vivo process.
(5) Pathological observation methods
With the development of the discipline, the research methods of pathology have gone far beyond the traditional classical morphological observation, and many new methods and techniques have been adopted to further deepen the research work, but morphological methods (including improved morphological methods) are still the basic research methods. The commonly used methods are briefly described as follows:
Gross observation is mainly to observe and detect the specimen and its pathological features (size, shape, color, weight, surface and section state, pathological features and firmness, etc.) with the naked eye or magnifying glass, measuring ruler and various weighing instruments. ) detailed. This method is simple and feasible, and experienced pathologists and clinicians can often determine or roughly determine the diagnosis or pathological nature (such as benign and malignant tumors, etc.). ) by naked eye observation.
Histological observation It is one of the most commonly used methods to observe and study diseases by making diseased tissues into sections with a thickness of several microns, and then observing their subtle lesions with a microscope after dyeing in different ways, thus improving the resolution of naked eye observation by a thousand times and deepening the understanding of diseases and lesions. At the same time, because various diseases and lesions often have certain histological characteristics, they can often be diagnosed through histological observation, such as the above biopsy.
Cytological observation uses a collector to collect exfoliated cells from the lesion site, or uses an empty needle to puncture and absorb tissue cells from the lesion site, or separates the lesion cells from the body cavity effusion, and makes cytological smear microscopic examination to understand the pathological characteristics. This method is often used for early diagnosis of some tumors (such as lung cancer, cervical cancer, breast cancer, etc.). ) and other diseases. However, due to the limitations and accuracy of materials, sometimes the diagnosis is inevitably limited. Not only the safety of puncture is improved, but also the accuracy of diagnosis is improved.
Ultrastructure observation Through transmission and scanning electron microscope (the resolution of electron microscope is higher than that of optical microscope 1000 times), the internal and surface ultrastructure of tissues, cells and some pathogenic factors are observed more carefully, that is, the pathological changes of cells are recognized and understood from the level of subcellular (organelles) or macromolecules. This is by far the most detailed morphological observation method. At the ultrastructural level, the changes of morphological structure can often be associated with the changes of functional metabolism, which is greatly conducive to deepening the understanding of diseases and lesions.
Histochemical and Cytochemical Observation By using histochemical and cytochemical methods with certain specificity, we can know the state of various chemical components in tissues and cells, such as protein, enzymes, nucleic acids, glycogen, etc. , thus deepening our understanding of morphological and structural changes. This method can not only reveal the changes of chemical composition of tissues and cells that can not be observed by ordinary morphological methods, but also often find the changes of chemical composition before the morphological structure changes. In addition, with the progress of immunological technology, we can also use immunohistochemical and immunocytochemical methods to understand the immunological characteristics of tissues and cells, which is very helpful for pathological research and diagnosis.
In addition to the above-mentioned common methods, a series of molecular biology techniques have been established in recent decades, such as autoradiography, micro-spectroscopy, morphological measurement (image analysis), analytical electron microscopy, flow cytometry (FCM), polymerase chain reaction (PCR) and molecular in situ hybridization, etc., so that the conventional pathomorphological observation has been developed to combine the morphological and structural changes of tissues and cells with chemical changes. Moreover, the traditional qualitative research has been developed into quantitative research on pathological morphology and chemical composition changes, thus obtaining a lot of updated new information and greatly deepening the depth of disease research. This is difficult to do in previous studies.