Objective To explore the role of pulmonary function analysis in drug efficacy evaluation of radiation-induced lung injury.Methods Totally 30 C57BL/6 mice were randomly divided into 3 groups:control group, radiation group and dexamethasone group.Mice in radiation group and dexamethasone group were irradiated with 20 Gy X-ray on the whole chest.Then mice in dexamethasone group was intraperitoneally injected with dexamethasone at the dose of 4.5 mg/( kg· d) for 2 weeks and then the dose was halved up to 1 month after radiation while control group and radiation group were intraperitoneally injected with 0.9%saline.One month after irradiation, pulmonary function of all the mice was tested with EMKA system.Then mice were sacrificed and pathological changes of pulmonary tissue were observed by HE staining. Furthermore, the area of alveolar cavity was measured with the Image-pro plus software.Results One month after irradiation, the pulmonary function parameters of mice in radiation and dexamethasone groups, such as mid-expiratory flow, minute volume,tidal volume,peak inspiratory flow,and peak expiratory flow,decreased obviously compared with the control group, but those parameters of the dexamethasone group decreased much less significantly than in the radiation group.The pathological changes of pulmonary tissues showed that the area of alveolar cavity of radiation group and dexamethasone group was smaller than that of the control group, but the extent of the loss of alveolar cavity area of the dexamethasone group was less than in the radiation group.Neutrophils infiltration could be found in the radiation group and dexamethasone group, but was less serious in the dexamethasone group.The result of pulmonary function analysis was coincident with pathological changes of the lung.Conclusion Dexamethasone can alleviate radiation induced pulmonary injury.Pulmonary function analysis combined with pathological observation of pulmonary tissues can effectively evaluate the efficacy of drugs in radiation induced lung injury.

Objective:To analyze the impact of previous exposure to macrolide, quinolones and nitroimidazole antibiotics on eradication rate of bismuth quadruple therapy (BQT) in newly diagnosed patients with Helicobacter pylori( H. pylori). Methods:A total of 469 patients with H. pylori initially treated at the Third Hospital of Peking University from September 2017 to August 2020 were retrospectively recruited. The therapeutic regimens were BQT containing clarithromycin/levofloxacin/metronidazole recommended by Chinese guidelines. Clinical data were collected, including general demographic data, exposure history of antibiotics, CYP2C16 metabolic pattern, endoscopic diagnosis, bacterial density, H.pylori resistance, eradication results, etc. Univariate analysis, Chi-square test, Fisher exact probability test, Kruskal-Wallis H test and Logistic regression model were used as statistical methods. Results:Among different eradication therapies, univariate and multivariate analyses suggested that previous exposure to macrolides ( OR=3.37,95 %CI 1.04-10.98, P<0.05) was relevant to the decreased eradication rate of BQT containing clarithromycin. This may be due to increased resistance to clarithromycin ( OR=6.12,95 %CI 3.99-9.40, P<0.01).The previous exposure to quinolones ( OR=3.65, 95 %CI 1.27-10.49, P<0.05) was relevant to the decreased eradication rate of BQT containing levofloxacin, which was probably explained by the increased resistance to levofloxacin ( OR=2.50, 95 %CI 1.69-3.71, P<0.01). But the previous history of nitroimidazole did not impact the efficacy of BQT containing metronidazole. Conclusions:In patients newly diagnosed with H.pylori infection, the previous exposure to macrolide or quinolones antibiotics is related to lower eradiation rates of H. pylori. Although the exposure to nitroimidazole also indicates drug resistance to metronidazole, the clinical efficacy of BQT with metronidazole 400 mg four times a day is not affected.

ObjectiveTo establish a set of single nucleotide polymorphisms (SNP) detection protocol for inbred rats based on multiplex PCR-ligase detection reaction (LDR). MethodsA total of 40 rats SNP sites were selected on chromosomes 1-20 and X of rats among 5 inbred strains of rats, and the 40 SNP sites were randomly divided into four groups. A genetic detection protocol for 4 groups of SNP in inbred rats based on multiplex PCR-LDR technology was constructed. 9 commonly used rat strains from two other domestic rat suppliers were detected by this protocol. Finally, the feasibility of this protocol was verified by comparing the amplification effects of different DNA polymerases by a third-party laboratory. ResultsWhen using the constructed SNP detection protocol for inbred rats to test 5 rat strains, all sites in each sample obtained good amplification results. The 9 commonly used rat strains from two other rat suppliers in china were also well amplified by this SNP detection protocol, and 40 SNPs were homozygous in each Inbred strain. The results of detection of the same rat DNA samples with three different DNA polymerases showed that the Multiplex PCR Kit, AmpliTaq Gold 360 DNA polymerase and Platinum II Taq hot start DNA polymerase had electrophoretic peaks of amplification products at all SNP sites in groups 1 to 3, and Platinum II Taq hot start DNA polymerase had one less electrophoretic peak of the amplification products at the SNP sites in group 4. In addition, inter-laboratory comparisons showed consistent results for the same amplification system. ConclusionBased on multiplex PCR-LDR technology, this study successfully established a SNP detection protocol for rats covering all autosomes and X chromosomes with the excellent stability and repeatability.