What Is Forensic Pathology?

Pathology is a basic medical science that studies the causes, mechanisms, development rules, and morphological structure, functional and metabolic changes, and disease outcomes of the body during the disease. Because of this, pathology has always been regarded as the "bridge discipline" between basic medicine and clinical medicine, which fully shows its important role in medicine, which is determined by the nature and task of pathology.

Forensic pathology

(Subject)

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Illness is an extremely complicated process. Under the interaction of the causative agent and the body's response function, various changes in the morphology, structure, and function of the affected part of the body will occur, which is an important basis for studying and understanding the disease. The mission of pathology is to use various methods to study the cause of disease (

There are various research methods for pathology. The research materials are mainly from patients (human pathological materials) and experimental animals and other experimental materials such as tissue culture and cell culture (experimental pathological materials).

(A) autopsy

Pathological examination (necropsy) of the dead body is one of the basic research methods of pathology. Autopsy can not only directly observe the pathological changes of the disease, so as to clear the diagnosis of the disease, find out the cause of death, help clinical discussion, verify the diagnosis and treatment are correct and appropriate, in order to summarize the experience and improve the quality of clinical work, In addition, it can timely detect and diagnose certain infectious diseases, endemic diseases, epidemics, and provide a basis for prevention and control measures. At the same time, it can also accumulate human pathological materials of common diseases, frequently-occurring diseases, and other diseases through a large number of autopsy. And prevention measures to contribute to the development of pathology. Obviously, autopsy is an extremely important method and means for studying diseases, and human pathological materials are the most valuable materials for studying diseases.

The level of autopsy in a country can often reflect the degree of civilization progress. The autopsy rate in many advanced civilizations in the world has reached more than 90%. Some countries have written regulations on autopsy. The rate of autopsy in China is still very low, which is very detrimental to the development of pathology and medical science in China and needs to be improved.

(Two) biopsy

With surgical methods such as local excision, forceps, puncture needle aspiration, scraping and removal, etc., the pathological examination of the diseased tissue is performed by the patient to determine the diagnosis, which is called biopsy, or biopsy for short. This is a widely used method of inspection and diagnosis. The advantage of this method is that the tissue is fresh and can basically maintain the true image of the lesion, which is conducive to the research of histology, histochemistry, cytochemistry, ultrastructure and tissue culture. For clinical work, this method of examination helps to make a timely and accurate diagnosis of the disease and judge the efficacy. Especially for diseases such as tumors of unknown nature, accurate and timely diagnosis is of great significance for treatment and prognosis.

(Three) animal experiments

Using animal experiment methods, models of certain human diseases can be reproduced on suitable animals, so that researchers can observe and study them in any way according to their needs, for example, they can perform continuous material inspection in stages to understand the disease or The occurrence and development of a certain pathological process and so on. In addition, animal experiments can be used to study the etiology, pathogenesis of certain diseases, and the effects and effects of drugs or other factors on the disease. The advantage of this method is that it can make up for the limitations and shortcomings of human observation, but there are all kinds of differences between animals and human bodies, and the results of animal experiments cannot be directly applied to human bodies, which must be paid attention to.

(IV) Tissue Culture and Cell Culture

A certain tissue or single cell is cultured in vitro with a suitable medium to observe the occurrence and development of cells and tissue lesions, such as tumor growth, canceration of cells, virus replication, chromosome mutation, and so on. In addition, foreign factors such as radiation and drugs can also be applied to observe its effect on cells and tissues. The advantage of this method is that it can be more convenient to observe and study various disease or disease processes in vitro and study the methods to affect it. It has a short cycle and quick results, which can save research time. It is one of the good research methods. However, the disadvantage is that after all, the isolated external environment is different from the overall environment in the body that is interconnected and affected by each other. Therefore, the research results cannot be treated in the same way as in vivo processes.

(V) Observation methods of pathology

With the development of disciplines, the research methods of pathology have far surpassed the traditional classic morphological observation, and many new methods and technologies have been adopted, which have further deepened the research work, but morphological methods (including improvements Morphological method) is still the basic research method. The common methods are briefly described as follows:

The general observation mainly uses the naked eye or auxiliary tools such as a magnifying glass, a ruler, various weighing instruments, etc. to perform inspection on the test material and its lesion characteristics (size, shape, color, weight, surface and section state, lesion characteristics and firmness, etc.) Careful observation and detection. This method is simple and easy, and experienced pathologists and clinicians can often determine or roughly determine the diagnosis or the nature of the disease (such as benign and malignant tumors) by gross observation.

Histological observation The diseased tissue is made into sections with a thickness of a few micrometers. After staining with different methods, the microscopic lesions are observed with a microscope, thereby improving the resolution of the naked eye by hundreds of times, and deepening the understanding of diseases and lesions. One of the most commonly used methods to observe and study diseases. At the same time, because various diseases and lesions often have a certain degree of tissue morphological characteristics, they can often be diagnosed by histological observation, such as the biopsy described above.

Cytological observation Use the collector to collect cells that have fallen off the diseased area, or use empty needles to puncture the tissues and cells on the diseased area, or isolate the diseased cells from the body cavity effusion to make a cytological smear for microscopic examination to understand Its lesion characteristics. This method is often used for the early diagnosis of certain tumors (such as lung cancer, cervical cancer, breast cancer, etc.) and other diseases. However, due to the limitations and accuracy of the materials, sometimes the diagnosis is inevitably limited. Not only improves the safety of puncture, but also improves the accuracy of diagnosis.

Ultrastructure observation Use transmission and scanning electron microscopy to make a more detailed observation of the internal and surface ultrastructure of tissues, cells, and some pathogens (electron microscopes have a resolution more than a thousand times higher than that of optical microscopes). Organelles) or macromolecular level to recognize and understand the pathological changes of cells. This is by far the most detailed morphological observation method. At the ultrastructural level, changes in morphology and structure can often be associated with changes in functional metabolism, which is greatly conducive to deepening the understanding of diseases and lesions.

Histochemical and cytochemical observations By using specific histochemical and cytochemical methods that reflect the chemical characteristics of tissue and cell components, you can understand tissues, various proteins, enzymes, nucleic acids, glycogen, and more in cells The status of chemical composition, so as to deepen the understanding of morphological changes. This method can not only reveal the changes in the chemical composition of tissues and cells that cannot be observed by ordinary morphological methods, but often can detect the changes in their chemical composition before the morphological structure changes. In addition, with the advancement of immunology technology, methods of immunohistochemistry and immunocytochemistry can also be used to understand the immunological characteristics of tissues and cells, which is of great help for pathological research and diagnosis.

In addition to the above-mentioned common methods, autoradiography, microspectroscopy, morphometry (image analysis), analytical electron microscopy, flow cytometry (FCM), and polymerase chain reaction (FCM) have been established in recent decades. A series of molecular biological technologies such as PCR) technology and molecular in situ hybridization technology, so that routine pathological morphological observations have been developed to combine morphological and structural changes with chemical changes in tissues and cells for research purposes. Qualitative research has evolved to quantitatively study the morphological and chemical components of pathological changes, thereby obtaining a lot of more updated new information, which has greatly deepened the depth of disease research. This is difficult to achieve in previous research.