What are the new technologies for diagnosing diseases?

Everyone knows the truth of treating diseases and saving lives. Whenever we go to the hospital, doctors often have to look, smell, ask and examine for a period of time, and prescribe several examination items, and only after the examination results come out will they prescribe the right medicine.

Indeed, if doctors want to save lives, they must first make a clear diagnosis. Under modern medical conditions, doctors can not only make a definite diagnosis of patients' organic diseases according to a large number of modern instruments such as B-ultrasound, nuclear magnetic resonance, CT and gastroscope, but also judge the nature and prognosis of diseases at the cellular and molecular levels. Gene diagnosis technology, which started in the late 1970s, has entered a new stage 10 years due to the emergence of new technologies such as PCR and the deepening of human understanding of their own genes, which has brought a profound revolution in the field of medical diagnosis.

In fact, people at the end of the 20th century were no strangers to gene diagnosis. On the one hand, the continuous updating of gene diagnosis methods not only reveals a large number of molecular defects of genetic diseases, but also can be diagnosed at the transcription level; On the other hand, the practicability of gene diagnosis is improving, and its application scope is gradually expanding from genetic diseases to infectious diseases, tumors, cardiovascular diseases, degenerative diseases, parasitic diseases and so on. Fetal prenatal diagnosis has become an effective means to improve the quality of the population. In addition, gene diagnosis technology is also widely used in forensic medicine. The difference between gene diagnosis and traditional diagnosis methods is that it can not only diagnose phenotypic diseases, but also find potential disease factors, such as determining whether people or fetuses with family history of genetic diseases carry pathogenic genes, individual susceptibility to diseases, types and stages of diseases, and even individual drug resistance. The traditional diagnosis method is only based on the phenotype of the disease, and often the disease shows typical symptoms, and the disease has developed to a certain extent, which brings difficulties to the treatment.

The rise of gene diagnosis was in the 1980s. From 65438 to 0980, according to the principle that the DNA fragments corresponding to different people are not exactly the same, which leads to different recognition sites of a restriction endonuclease, the DNA system obtained by using this restriction endonuclease to cut the DNA of gene tissue appears length polymorphism in the population, a DNA restriction length polymorphism analysis method was established, which made it possible to locate any gene related to phenotype on the chromosome. According to this linkage analysis, more than 400 genes were located and cloned, such as Huntington's disease, cystic fibrosis and breast cancer genes. This makes the existing diagnostic strategy based on gene function a step forward. With the continuous development and improvement of location-based cloning gene diagnosis strategy, people have noticed that most human diseases, such as severe obesity, asthma, tumor, mental illness and various autoimmune diseases, are the result of the interaction between multiple genes and the environment. The concept of phenotypic cloning proposed by scientists in 1995 provides a new idea for gene location cloning, and also makes it possible for gene diagnosis to move from simple traits to complex traits. The basic idea is to start with the similarity or difference between normal and abnormal genomes, or to find different sequences or the same sequence, to isolate and identify the genes related to the studied disease, and then to determine the molecular defects that cause the disease. This strategy does not specify the biochemical function or map location of genes in advance, nor is it affected by the number of genes or their interaction mode.

Specific methods of gene diagnosis include DNA probe hybridization, PCR or both. In recent years, with the rapid development of biochip technology, especially gene chip technology, and the large-scale cloning of new human genes, gene diagnosis technology has developed from the previous diagnosis of one or several genes to intensive gene diagnosis-that is, diagnosis of hundreds, thousands or even tens of thousands of genes at the same time. In this way, after detecting all the genes related to a certain disease, targeted drug therapy or gene therapy can be taken according to different genotypes of patients, so as to achieve the best therapeutic effect. This method is not only simple, but also can be used for diagnosis with only one cell sample. Due to the development of gene chip technology, people's gene diagnosis may not only run through the whole process of disease treatment, but also run through people's life-from the early period before the birth of the fetus to individual death, and the most diagnostic results can be obtained through biological information processing. Through early prediction and early treatment, real disease prevention and treatment can be achieved.

In recent years, the rapid development of gene diagnosis technology has benefited from the development of life science and technology, information science and technology, microstructure manufacturing and analysis technology, and the increasingly close cooperation between disciplines, which has made great contributions to the progress of human health and greatly promoted the development of the whole life science. For example, Chinese and foreign pharmaceutical companies in Japan sell two kinds of DNA probes: one is to identify mycobacterium tuberculosis and the other is to identify amorphous acid-fast bacteria. At present, there are about 800 ~ 654.38+10,000 tuberculosis examinations and 25 ~ 45,000 amorphous acid-fast bacteria examinations in Japan every year. These identifications require long-term bacterial culture, and then the samples are detected by conventional methods, which takes a long time. After the sensitivity is greatly improved, the DNA probe can be directly determined from the sample, which greatly speeds up the diagnosis of patients in time and does not delay the timing of medication.