Objective To establish a DNA quantitation method based on dithiothreitol(DTT)-crystal vio-let.Methods DTT was used to decolorize crystal violet,mixed with different concentrations of λ-DNA and salmon sperm DNA standard samples or concentration standard samples,and the absorbance was read at 595 nm wavelength by microplate reader,and compared with the results of ultraviolet absorbance method.DTT-crystal violet method and ultraviolet absorbance method were used to compare the concentration of plasmid samples and the concentration of genomic DNA samples of cervical exfoliated cells.The protein tolerance of the two methods was assessed by simulating protein contaminants with bovine serum albumin(BSA).Results In the quantification of λ-DNA and salmon sperm DNA,the DTT-crystal violet method had a robust linear correlation between the absorbance at 595 nm and DNA concentration(r2＞0.95),and the measured concentrations of the standard samples were not significantly different from the theoretical concentrations of the prepared standard samples(P＞0.05).There was no significant difference in the concentration of plasmid samples measured by DTT-crystal violet method and ultraviolet absorption method(P＞0.05).The concen-tration of DNA samples from cervical exfoliated cells measured by ultraviolet absorption method was positive-ly correlated with that by DTT-crystal violet method(r=0.94,P＜0.01).The concentration of the standard sample containing BSA 1 μg/μL measured by ultraviolet absorption method was higher than that of the con-trol sample,and the difference was statistically significant(P＜0.01),whereas the DTT-crystal violet method was not significantly affected(P＞0.05).Conclusion DTT-crystal violet method has obvious advantages over the existing DNA quantitation method,and is suitable for DNA quantitative analysis in scientific research and clinic.

Objective:To evaluate the radiation shielding performance for a novel self-shielded ZAP-X radiotherapy system used for intra-cranial and neck treatments. The present evaluation was performed according to the relevant Chinese national standards and the clinical placement of the radiotherapy system in an unshielded treatment room.Methods:The radiation source of the ZAP-X was a 3 MV linear accelerator. A total of 33 detection sites were selected surrounding the self-shielded system at 1.3, 2.3 and 3.3 m away from the periphery of the equipment. The maximum ambient dose equivalent rate in each irradiation condition was measured accordingly. A commonly used clinical treatment plan was selected to simulate the treatment process. During the delivery of this treatment plan, the cumulative doses of these 33 sites were measured, separately. The applicable current radiation protection standard for radiotherapy in China was chosen to evaluate the radiation shielding performance of the system.Results:According to the measurement result of the ambient dose equivalent rates along the aforementioned perimeter lines, a suggestion was put forward to redefine the existing 1 m controlled area by determining the distance at which the instantaneous dose rate of 10 μSv/h will not be exceeded. This is to meet the requirements of the Chinese standard GBZ 121-2020.Conclusions:According to the existing Chinese national radiation protection standards, the self-shielded radiotherapy system in the unshielded treatment room has the clinical applicability in China. But for such a novel self-shielded system, the corresponding performance testing and radiation protection standards shall be formulated.

Objective To analyze the factors influencing the levels of occupational exposure in medical radiation workers in China, and to provide a scientific basis for determining the key points of radiation protection in the medical sector. Methods The individual monitoring data on occupational external exposure in medical radiation workers in 2021 were collected from the “National Individual Dose Registry”. The Chi-squared test and logistic regression were used to analyze the factors influencing the levels of occupational exposure in medical radiation workers. Results The Chi-squared test showed that gender, occupational category, medical institution category, region, number of radiation workers per thousand population, and regional per capita GDP were significantly associated with occupational exposure in medical radiation workers exceeding the annual effective dose of 5 mSv and an annual effective dose limit of 20 mSv (χ² = 21.456−262.329, 7.601−78.650, P < 0.05). The logistic regression analysis further showed that gender, occupational category, region, and number of radiation workers per thousand population were factors influencing the occupational exposure in medical radiation workers exceeding the annual effective dose of 5 mSv (χ² = 14.621−170.857, P < 0.05); gender, occupational category, region, and regional per capita GDP were factors influencing the occupational exposure in medical radiation workers exceeding the annual effective dose of 20 mSv (χ² = 5.401−48.709, P < 0.05). Conclusion Male radiation workers in interventional radiology and in central China have high risks of exceeding annual effective doses of 5 and 20 mSv. Moreover, high number of radiation workers per thousand population and regional per capita GDP are associated with low risks. Medical institutions should maintain a sufficient number of radiation workers and strengthen training on radiation protection knowledge for male and interventional radiology workers to enhance their radiation protection awareness. Investigation of the factors contributing to the high occupational exposure in central China should be intensified, and targeted effective measures should be conducted to reduce the occupational exposure in medical radiation workers.

Objective To simulate and analyze the CT examination doses to typical patients based on Chinese reference human phantom, and to develop an online software for assessing the organ absorbed dose and effective dose to the examinees undergoing CT examination in order to provide a tool for rapid assessment of radiation dose from CT examination. Methods Based on the Monte Carlo simulation, a GE LightSpeed 16 CT scanner was modeled. The organ doses to Chinese adult male, female and 1 year-old child male from single axial scan were calculated based on the Chinese reference phantoms and an organ dose database was established. A web-based CT dose assessment software was developed to read the data from the organ dose database according to the CT scanning parameters entered by the user and to calculate the organ absorbed dose and effective dose rapidly. Results A new CT dose assessment software was developed, which can be used to assess organ doses to Chinese adult male, female and 1-year-old male for different CT scanner, voltage, current, collimator width and other CT parameters. The organ doses calculated in this work were compared with simulation data in two relevant studies. Dose differences for the organs completely included in the scan range were small, with relative differences less than 15％ and 25％, respectively. Conclusions The CT dose assessment software provides a powerful tool for the simple and rapid assessment of radiation dose to the examinees undergoing CT examinations.

Objective: To identify whether the three imported yellow fever cases in China in March 2016 were infections by wild type strain of yellow fever virus in Angola in 2016, vaccine-associated disease or co-infection of both. Methods: Sequences of three yellow fever virus strains were obtained by high-throughput sequencing with IonTorrent PGM platform from blood or urine samples of three yellow fever cases, and their genomic characteristics were analyzed. Then the regions with relatively great difference between the wild type strain and 17D vaccine strain were identified, and then served as the reference sequences when mapping the reads obtained by high-throughput sequencing. Results: Partial yellow fever virus genomes were obtained from three samples of yellow fever patients, among them a full length coding region sequence was gained in sample 2. Comparing the genome sequences, the three newly obtained strains of yellow fever virus were highly similar to strain CNYF01R / 2016 which was isolated from the first imported yellow fever case to China in 2016 and strain Angola 71 from Angola in 1971, and they all belonged to Angola genotype of yellow fever virus. In this study, we found five regions in yellow fever virus genomes with great diversity between the vaccine strain and the wild type strain. In these five regions, a number of short reads obtained by high-throughput sequencing of the three samples were mapped to the sequence of wild type virus, while no short reads matched the vaccine strain. Conclusions There were no viral nucleic acid of 17D vaccine strain in the blood or urine samples of these three cases of yellow fever. They are all infected by wild type strains of Angola in 2016.

Objective To sequence the whole genome and to analyze the molecular and evolutionary of Hantavirus(HV) isolated from peripheral blood leukocytes (PBMC) of HFRS patients.Methods PBMC were isolated from peripheral blood of HFRS patients and cocultured with Vero-E6 cells.Quantitative realtime RT-PCR and IFA tests were used to detect virus titer.The genome segments were amplified by PCR with predesigned primers,whole sequence were obtained and further study on its evolution was analyzed.The differences between the isolate strains and Vaccine strain were tested by microneutralization test.Results Two Hantaan virus strains were isolated from PBMC of HFRS patients successfully.The whole genomic fragments were obtained.Molecular phylogenetic analysis result showed that both of the strains had the comparatively high similarity with XAAa10091712 strain.The seroneutralization titer of SX26 and Z10 had significant differences.Conclusion Hantaan virus could be successfully isolated from PBMC of HFRS patients,and it proved to be a feasible way of isolation of hantavirus from peripheral white blood cells;The microneutralization test proved that the antigenicity of two strains exist significant differences.It provided basis for the further study of hantavirus epidemic strains in this region.

Objective To investigate the clinical efficacy and safety of flexible ureteroscopic lithotripsy ( FURL) using holmium laser for medullary sponge kidney stones. Methods A flexible ureteroscope was placed into renal calyx via a ureteral access sheath ( UAS) . The stones underlying the mucosa were found,and then broken by holmium laser following incision of renal papillary mucosa. The stone fragments were washed or clamped out. The remission of clinical symptoms and incidence of perioperative complications were observed,and a KUB plain film was rechecked postoperatively. Results Stones underlying mucosa were found and broken successfully in all 14 patients and there was no serious bleeding. Back pain symptoms of patients were relieved in 3 to 7 days postoperatively or after the removal of double J stent. The stone fragments were mainly discharged spontaneously. The rechecking KUB showed the amount of stones of most patients was significantly re-duced three months after operation. Conclusion FURL using holmium laser is effective for the treatment of medullary sponge kidney stones as it can significantly reduce the loads of stones without serious complications. It’ s a minimally invasive,effective,safe and suitable way which is suitable for further spread of clinical application.

The aim of this study was to evaluate the safety and efficiency of a novel, oncolytic adenovirus mutant M1 administered in conjunction with immunosuppressive agents. Animal models were established by administering purified M1 either intravenously or retroperitoneally. At different time points, blood samples were taken from the mice for testing of liver and renal function. Microscopic examination of the liver was performed to observe pathological changes. Immunohistochemical analyses were used to evaluate the expression of the adenovirus in the liver. Lymphocyte recruitment to the liver and the activation of adenovirus specific T cells were also analyzed. No signs of general toxicity were observed, but transient increases in ALT and Scr were observed following the administration of M1. Microscopic examination revealed a mild inflammatory response in the liver. Compared to intravenous injection, higher expression levels of adenoviral proteins were observed after retroperitoneal injection. Combined treatment with cyclosporine A resolved the liver and kidney dysfunction and increased the concentration of the adenovirus in the liver. The use of the novel oncolytic adenovirus mutant M1 in vivo is safe, and the combined administration of M1 with immunosuppressive agents was able to enhance the effectiveness and safety profile of M1.
Adenoviridae ; genetics ; immunology ; Animals ; Female ; Kidney ; immunology ; virology ; Liver ; immunology ; virology ; Mice ; Mice, Inbred BALB C ; Mutation ; genetics

The aim of this study was to evaluate the safety and efficiency of a novel, oncolytic adenovirus mutant M1 administered in conjunction with immunosuppressive agents. Animal models were established by administering purified M1 either intravenously or retroperitoneally. At different time points, blood samples were taken from the mice for testing of liver and renal function. Microscopic examination of the liver was performed to observe pathological changes. Immunohistochemical analyses were used to evaluate the expression of the adenovirus in the liver. Lymphocyte recruitment to the liver and the activation of adenovirus specific T cells were also analyzed. No signs of general toxicity were observed, but transient increases in ALT and Scr were observed following the administration of M1. Microscopic examination revealed a mild inflammatory response in the liver. Compared to intravenous injection, higher expression levels of adenoviral proteins were observed after retroperitoneal injection. Combined treatment with cyclosporine A resolved the liver and kidney dysfunction and increased the concentration of the adenovirus in the liver. The use of the novel oncolytic adenovirus mutant M1 in vivo is safe, and the combined administration of M1 with immunosuppressive agents was able to enhance the effectiveness and safety profile of M1.

Objective To introduce the general international method for estimation of lifetime risk of developed cancer,and to estimate the lifetime risk baseline values of several kinds of cancers related to radiation exposures in China.Methods The risk estimation was based on the data from Chinese Cancer Registry Annual Report (2010) and China Population & Employment Statistics Yearbook (2009),and made according to the method previously published by National Cancer Institute (NCI) in USA.Results The lifetime risk of all cancer in China in 2007 was estimated to be 27.77％,that of lung cancer 5.96％,that of breast cancer for female 3.34％,that of all leukemia 0.14％,that of thyroid cancer 0.37％.The lifetime risks of all cancer were estimated to be 32.74％ for males and 24.73％ for females,and that was 36.47％ for urban residents and 26.79％ for rural people.Conclusions The lifetime risk of all cancer for males in 2007 was about 1.25 times as much as that for females.The value of all cancer for urban residents was about 1.35 times as much as that for rural residents.The lifetime risk of developed cancers in 2007 in China is lower than that in the developed countries,such as Japan.