Autoradiography is a technology that uses radioactivity to sensitize photographic emulsion and film to locate radioactive molecules in samples.radio isotopeIn the process of decay, ionizing radiation is emitted, which can sensitize the photographic emulsion.After the latex contacts with the specimen, the silver bromide colloid where the radioactive substance exists is reduced to produce silver particle precipitation, thus showing the location where the radioactive substance exists.[1]
principle
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When this technology is applied, compounds containing radioisotopes are first introduced into the organism. After a certain period of time, their tissues are taken down and made into slices or smears, and then they are contacted with photographic emulsion.Since alpha and beta particles generated by radioactive elements can interact with visible light on photographic emulsion, the correct position of radioisotopes can be obtained by developing and fixing with ordinary photographic technology.The content of radioactive substances is measured according to the blackening degree of the action of radioactive elements on the latex, that is, the number of black silver particles on the latex.In autoradiography, the commonly used isotopes are hydrogen 3, carbon 14, phosphorus 32, sulfur 35, iodine 131, iodine 125, etc.[2]
Operation method
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The first step of autoradiography is to prepare radioisotope labeled compounds, usually using isotopes that emit low-energy beta rays, such asfourteenC、threeH, etc.Then, makeLabeling compoundIt is absorbed by biological tissues or cells and participates in biological metabolism.The tissue containing the marker compound is made into a slice, placed on the slide, and then the surface of the slice is coated with a thin layer of latex, and placed in the cassette for a certain time for radioactive "exposure".Finally, according to the process of processing the photographic negative, the silver particles reduced by the ray are displayed after developing and fixing.Since the position of radioactive compound in the slice coincides with the precipitation of silver particles, the silver particles can indicate the location where radioactive compound exists.Sometimes, the sections can be dyed again to make the marked parts clear.Autoradiography can be made foroptical microscopeThe observed specimen can also be made for electron microscope observation, and its resolution is about 0.1 μ m.In the process of autoradiography specimen processing, the self coating emulsion step must be carried out in a tight darkroom to avoid the interference of natural light, increase the background and reduce the autoradiography effect.
Autoradiography is mainly used forLabeling compoundThe distribution and dynamic changes of the.Autoradiography is also an important means of gene mapping, namely the so-calledIn situ hybridization。RNA and the DNA sequence (gene) it encodes have the complementary relationship of base pairing at the molecular level, so they can combine with each other to form a DNA RNA molecular hybrid.If the radiolabeled RNA interacts with the cell slice,RNA can then be combined with its complementary DNA fragment in the chromosome. After autoradiography, this section will show the specific chromosome location where the RNA gene exists, providing valuable data for genetics and genetic engineering.[1]
Research History
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Autoradiography has a history of more than 100 years, but in terms of application scope and depth of problem solving, it has developed particularly rapidly in the past 20 years.Autoradiography can be divided into four levels: overall level, tissue level, cellular level and molecular level.The outstanding advantages of autoradiography are: intuitive results, realistic records, and avoiding personal bias in interpretation;Autoradiography can unify the form, function and metabolism to study the dynamic change process in the organism, which is unique, so it is called the modern functional morphology method;High sensitivity, even the counting rate that can be as low as once a day may also be recorded;Easy to operate.Because autoradiography has the above advantages, especially in recent years due to the improvement of latex andthreeApplication of H-labeled compounds, resolution use of autoradiographyelectron microscopeIt has reached below 0.1 μ moptical microscope1 μ m, together with many improvements in autoradiography, has been widely used in biological and medical research.[3]
Developing and fixing
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For the image obtained by the general photographic process, the fixed image can be obtained only by developing and fixing.
Development is essentially an oxidation-reduction process.Development starts from the development center. First, the developer (reducing agent) emits electrons and oxidizes itself.Then, silver ions (oxidants) in silver bromide crystals receive electrons and are reduced to silver atoms.In general, the actual process is that the AgO crystal first adsorbs bromine ions to form a negative layer.The positive potassium ions are adsorbed outside the negative layer to form a positive layer.In this way, a double electric layer with a certain electrostatic potential is formed between the surface of silver bromide crystal and the solution.In the development process, the developer must pass through the double electric layer and be adsorbed to the surface of silver bromide crystal to start the development process.According to the electrode theory, the development center on the surface of silver Auschwitz crystal is a silver micro spot, so it absorbs less bromine ions, and its double electric layer is weak. In this way, the negatively charged developer is easy to be adsorbed on the development center.The silver micro spot has good conductivity. Electrons enter the silver bromide crystal from the developer through the silver micro spot and neutralize with silver ions to form silver atoms.The above process can be summarized as three basic steps, namely, the developer is adsorbed on the surface of sensitized silver bromide crystal;The developer releases electrons and the electrons are transferred to the developing center;Electrons combine with silver ions in silver bromide crystals to form silver atoms, which are deposited in the development center.In order to meet the development conditions, the pH value and bromine ion concentration of the development solution must be controlled.
After development, there is still a considerable amount of silver halide in the emulsion layer that has not been reduced to atomic silver. The basic role of the fixing process is to dissolve the photosensitive silver halide remaining in the emulsion layer from the emulsion layer and fix the image formed by development. During the fixing process, the fixing agentSodium thiosulfateIt reacts with silver halide to form a complex of silver soluble in water, but does not dissolve the reduced metal silver.
Absolute lymphocyte count and multiple bone marrow
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Multiple myeloma（multiple myeloma，MM) is a B-cellMalignant tumorIt is common in middle-aged and elderly people, and is characterized by the accumulation of a large number of malignant plasma cells in bone marrow and the secretion of monoclonal immune globules.The clinical manifestations of myeloma are complex, and there are many factors that affect the prognosis. The survival period varies from several months to decades.Traditional prognostic indicators include age, plasma cell indexβ 2-microglobular egg self (β 2-MG), molecular cytogenetics, etc.There have been literature reports in recent yearsPeripheral blood lymphocytesAbsolute lysimeter count,ALC) has also become one of the prognostic factors of malignant hematopathy.[4]At the same time, studies have confirmed that ALC is low at the time of initial onsetDiffuse large B-cell lymphomaandFollicular lymphomaThe survival period of patients is short and the prognosis is poor, but the prognosis of ALC and MM at home and abroadCorrelation studyLess.Therefore, this paper retrospectively analyzed 102 patients with initial MM, analyzed the correlation between ALC and clinical characteristics and other prognostic factors, and speculated the feasibility and clinical application value of ALC as a prognostic indicator of MM.
Research object
We collected 102 cases of MM patients who were initially diagnosed in Tianjin Medical University Cancer Hospital from December 2007 to February 2012. The disease diagnosis and staging refer to Zhang Zhinan's《Diagnostic and therapeutic criteria for hematopathy》(Third Edition).There were 63 males and 39 females, with a median age of 60 (33-83) years.Durie Salmon (D-S) staging: 42 cases in stage I and II, 60 cases in stage 111.International classification system (ISS) classification: 56 cases in stage I and II, 46 cases in stage 111.According to the self type of M eggs, they are divided into: IgG type 45 cases28 cases of IgA typeThere were 8 cases of K light chain type, 15 cases of entering light chain type, 3 cases of non secretory type, and 3 cases of plasma cell autohemopathy.According to renal function, 80 cases in group A,22 cases in group B.
method
102 patients with myeloma were retrospectively analyzed, and their age, sexALC、Lactate dehydrogenase (LDH), albumin (ALB)β2-MG、Creatinine (Cr) and its overall survival,OS) were grouped according to the median of corresponding ALC, and then the correlation between ALC and other clinical indicators was statistically analyzed.
follow-up
The deadline for follow-up was February 29, 2012.The total survival time is calculated from the time of diagnosis to death or the last follow-up.All the lost patients were counted until the last follow-up day, and were treated as censored data.The follow-up method was telephone follow-up.
statistical analysis
SPSS10.5Statistical software packageConduct statistical analysis.The counting data between groups were χtwoThe measurement data is subject to t test.The survival probability is estimated by Kaplan Meier method, and the results are calculated by Log rank methodSignificance test。P<0.05 means the difference is statistically significant.[5]
