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Objective:To asscentain the 131I activity concentration in 131I treatment workplaces and to explore the method of estimating the internal dose to workers by air sampling and to analyze its influencing factors. Methods:Air sampling method was used to collect aerosols containing radioactivity in 10 randomly selected workplaces in Zhengzhou where 131I therapy was performed. Aactivity concentration of 131I in treatment workplace was measured for gamma emitters by gamma-ray spectrometry. The internal dose due to 131I inhalation was estimated based on measurement result and field investigation result. Results:The activity concentration of 131I in air samples from 19 subpacking rooms ranged from 0.087 to 570 Bq/m 3, with an average of (51.04 ± 128.58) Bq/m 3. Those from 11 wards ranged from 0.162 to 54.6 Bq/m 3, with an average of (7.97 ± 15.89) Bq/m 3. In terms of the work hours recommended by the national standard GBZ 129-2016 Specifications for individual monitoring of occupational internal exposure, the estimated annual effective dose to radiation workers due to the inhalation of 131I ranges from 0.002 to 10 mSv, with an average of (0.61 ± 1.80) mSv, below the dose limit specified in the national standards. Conclusions:The samples with high 131I activity concentration in nuclear medicine workplaces of 10 medical institutions selected in Zhengzhou are mostly distributed in tertiary class hospitals operating large amount of radionuclide with large numbers of thyroid cancer patients adimitted. The result ing internal dose to radiation workers cannot be ignored. Estimating the internal dose based on the measurement result of air samples has a large uncertainty.However, air sampling method can promptly detect radioactive contamination in case of abnormal events or accidents, providing early warning for workers to carry out dose measurement from external exposure and internal exposure assessment.
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Coronavirus disease 2019 (COVID-19) caused by the severe acute respiratory syndrome coronavirus 2 (SARS-CoV-2) is currently the most significant public health threats in worldwide. Patients with severe COVID-19 usually have pneumonia concomitant with local inflammation and sometimes a cytokine storm. Specific components of the SARS-CoV-2 virus trigger lung inflammation, and recruitment of immune cells to the lungs exacerbates this process, although much remains unknown about the pathogenesis of COVID-19. Our study of lung type II pneumocyte cells (A549) demonstrated that ORF7, an open reading frame (ORF) in the genome of SARS-CoV-2, induced the production of CCL2, a chemokine that promotes the chemotaxis of monocytes, and decreased the expression of IL-8, a chemokine that recruits neutrophils. A549 cells also had an increased level of IL-6. The results of our chemotaxis transwell assay suggested that ORF7 augmented monocyte infiltration and reduced the number of neutrophils. We conclude that the ORF7 of SARS-CoV-2 may have specific effects on the immunological changes in tissues after infection. These results suggest that the functions of other ORFs of SARS-CoV-2 should also be comprehensively examined.
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Objective To investigate the effects of Lactobacillus rhamnosus GG (LGG) colonization in early life on intestinal barrier and intestinal development in offspring mice and its possible mechanism.Methods Six C57BL/6 pregnant mice with the same conception time of 6 weeks were selected and randomly divided into experiment group given 108 cfu/ml LGG live bacteria and control group given LGG inactivated bacteria by gavage from the 18th day of pregnancy until natural birth.The progeny mice in the two groups were continued to be gavaged with 107 cfu/ml of LGG live bacteria or LGG inactivated bacteria on days 1-5 of birth.The body weight changes of 3 week'progeny mice were recorded.The colonization of LGG bacteria in offspring mice was detected at 2nd and 3rd weeks.The mRNA of intestinal proinflammatory cytokines and tight junction molecules were evaluated by real-time PCR method.HE,immunohistochemistry,immunofluorescence staining and enzyme-linked immunosorbent assay were used to evaluate the intestinal barrier of 3-week old off spring mice.Results Compared with the control group,the progeny mice of the experiment group showed no significant difference in body weight at the first week,and the body weight increased at the second week and the third week [2ndweek:(3.790±0.240) g vs.(4.326±0.140) g,t=3.707,P=0.006;3rd week:(7.295±0.326) g vs.(8.040±0.370) g,t=3.130,P=0.011].LGG colonization can be detected only in the feces of progeny mice in the experiment group.Intestinal colonization can promote the growth of small intestine villi and colon crypt depth [jejunum:(320.000±22.514) μm vs.(265.100±15.611) μm,t=8.258,P＜0.001;ileum:(150.500±13.099) μm vs.(111.000±11.308) μm,t=9.958,P＜0.001;colon:(295.000±15.209) μm vs.(233.100±6.678) μm,t=9.129,P＜0.001].Compared with the control group,the number of goblet cells in the colonic crypt of the experiment group increased (11.62 ± 0.780 vs.35.24 ±1.370,t=15.000,P＜0.001),and the relative mRNA expression levels of pro-inflammatory factors as IFN-γ (1.280±0.232 vs.0.512±0.206,t=4.970,P=0.001),IL-6 (1.364±0.271 vs.0.941±0.215,t=2.452,P=0.040),IL-10 (1.341±0.320vs.0.744±0.294,t=2.762,P=0.025)andTNF-α (3.702±0.150 vs.2.581±0.500,t=2.553,P=0.034) in the experiment group decreased;the expression levels of the intimate tight junction molecules (Claudin3) (1.283±0.152 vs.1.881±0.172,t=4.932,P=0.001) and the atresia protein molecule (Occludin) (1.164±0.342 vs.0.812±0.224,t=3.67,P=0.016) significantly increased.Conclusion Early life LGG colonization protects the intestinal barrier by inhibiting lowgrade intestinal inflammation.This study will lay the experimental foundation for the supplementation of probiotics in early life so as to prevent intestinal diseases.
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Fish oil is an important nutrient component in rainbow trout bone, and the optimization of extraction by enzymatic hydrolytic method is of great significance.This study selected the alkaline protease as the hydrolytic enzyme, and optimized the process conditions of enzymatic hydrolysis of rainbow trout fish using single factor analysis method.Effects of several factors on the extraction of fish oil were studied, including the ratio of material to liquid, pH, enzymatic hydrolysis time, enzymatic hydrolysis temperature and amount of enzyme.Fatty acids were identified by gas chromatography-mass spectrometry (GC-MS).Results showed that the optimum extraction parameters of enzymatic hydrolysis were as follows: 2000 U/g alkaline protease, ratio of material to liquid of 1∶1 (w/w), pH 7.5, and extraction at 55℃ for 3h.It was found that the main composition of rainbow trout bone oil was unsaturated fatty acid with the content of 80.4% (w/w).The relative content of monounsaturated fatty acid and polyunsaturated fatty acid was about 76.9% (w/w) and 23.1% (w/w), respectively.The total content of EPA and DHA was 3.4% (w/w).This study optimized the extraction method of rainbow trout fish oil, analyzed and identified the main volatile compounds, and identified the main substances contributing to fish oil flavor.The method thus was of significance for the analysis and identification of fish oil products.