Objective:To explore the binding characteristics of N, N-diethyl-2-(2-(4-(2- 18F-fluoroethoxy)phenyl)-5, 7-dimethylpyrazolo[1, 5-a]pyrimidin-3-yl)acetamide ( 18F-DPA-714) and ( R)- N-sec-butyl- N-methyl-4-(3-( 18F-trifluoromethyl)phenyl)quinazoline-2-carboxamide ( 18F-TFQC) to the single nucleotide polymorphisms of the 18×10 3 translocator protein (TSPO), and to evaluate the imaging efficacy and feasibility of those 2 molecular probes in neuroinflammation rat models. Methods:To test the selectivity of 18F-DPA-714 and 18F-TFQC for TSPO polymorphisms, the wild-type (high-affinity binding, HAB) and mutant (low-affinity binding, LAB) sequences of the human TSPO gene were transfected into 293T cells respectively. A competitive inhibition assay was carried out with N-methyl- N-(1-methylpropyl)-1-(2-chlorophenyl)-3-isoquinoline carboxamide (PK11195) as an inhibitor to determine the binding affinities of 2 probes to TSPO polymorphisms. Rat neuroinflammation models ( n=6) were established using lipopolysaccharide. Three days after modeling, small animal PET/CT imaging was performed using 18F-DPA-714 and 18F-TFQC, respectively, to observe and compare the uptake of the tracers, and the ratio of SUV mean of the right striatum to SUV mean of the left striatum (SUVR) was calculated. After the imaging, the expression and distribution of microglia and TSPO were detected by tissue immunofluorescence. Repeated-measures analysis of variance was used to analyze the SUVR data of different groups. Results:The inhibition constants ( Ki) of 18F-TFQC on 293T-LAB and 293T-HAB cells were 23.51 and 14.60 nmol/L, respectively, with a Ki LAB/ Ki HAB ratio of 1.61, indicating low sensitivity to TSPO single nucleotide polymorphisms. The Ki of 18F-DPA-714 for binding to 293T-LAB and 293T-HAB cells were 45.23 and 6.47 nmol/L, respectively, with a Ki LAB/ Ki HAB ratio of 6.99. Small animal PET/CT imaging demonstrated that specifically uptake of both probes could be found in neuroinflammatory lesions. The overall SUVR of 18F-DPA-714 in the lesions within 60minutes was slightly higher than that of 18F-TFQC, but no significant difference was observed ( F values: inter-group 0.40, time effect 0.30, cross-effect 0.03; all P>0.05). Conclusions:Compared with 18F-DPA-714, 18F-TFQC is less sensitive to TSPO gene polymorphisms, thus being more suitable for clinical application and promotion. It holds promise for the early identification of neuroinflammation and the efficacy monitoring of anti-inflammatory drug treatments.

Objective:To explore the binding characteristics of N, N-diethyl-2-(2-(4-(2- 18F-fluoroethoxy)phenyl)-5, 7-dimethylpyrazolo[1, 5-a]pyrimidin-3-yl)acetamide ( 18F-DPA-714) and ( R)- N-sec-butyl- N-methyl-4-(3-( 18F-trifluoromethyl)phenyl)quinazoline-2-carboxamide ( 18F-TFQC) to the single nucleotide polymorphisms of the 18×10 3 translocator protein (TSPO), and to evaluate the imaging efficacy and feasibility of those 2 molecular probes in neuroinflammation rat models. Methods:To test the selectivity of 18F-DPA-714 and 18F-TFQC for TSPO polymorphisms, the wild-type (high-affinity binding, HAB) and mutant (low-affinity binding, LAB) sequences of the human TSPO gene were transfected into 293T cells respectively. A competitive inhibition assay was carried out with N-methyl- N-(1-methylpropyl)-1-(2-chlorophenyl)-3-isoquinoline carboxamide (PK11195) as an inhibitor to determine the binding affinities of 2 probes to TSPO polymorphisms. Rat neuroinflammation models ( n=6) were established using lipopolysaccharide. Three days after modeling, small animal PET/CT imaging was performed using 18F-DPA-714 and 18F-TFQC, respectively, to observe and compare the uptake of the tracers, and the ratio of SUV mean of the right striatum to SUV mean of the left striatum (SUVR) was calculated. After the imaging, the expression and distribution of microglia and TSPO were detected by tissue immunofluorescence. Repeated-measures analysis of variance was used to analyze the SUVR data of different groups. Results:The inhibition constants ( Ki) of 18F-TFQC on 293T-LAB and 293T-HAB cells were 23.51 and 14.60 nmol/L, respectively, with a Ki LAB/ Ki HAB ratio of 1.61, indicating low sensitivity to TSPO single nucleotide polymorphisms. The Ki of 18F-DPA-714 for binding to 293T-LAB and 293T-HAB cells were 45.23 and 6.47 nmol/L, respectively, with a Ki LAB/ Ki HAB ratio of 6.99. Small animal PET/CT imaging demonstrated that specifically uptake of both probes could be found in neuroinflammatory lesions. The overall SUVR of 18F-DPA-714 in the lesions within 60minutes was slightly higher than that of 18F-TFQC, but no significant difference was observed ( F values: inter-group 0.40, time effect 0.30, cross-effect 0.03; all P>0.05). Conclusions:Compared with 18F-DPA-714, 18F-TFQC is less sensitive to TSPO gene polymorphisms, thus being more suitable for clinical application and promotion. It holds promise for the early identification of neuroinflammation and the efficacy monitoring of anti-inflammatory drug treatments.

Objective To analyze the clinical manifestations,bacterial resistance to antibiotics and risk factors of mortality in pneumonia patients with Acinetobacter baumannii(AB) positive in respiratory secretions.Methods Clinical datas of pneumonia patients with AB positive in respiratory secretions in ICU from June 2012 to June 2017 were analyzed.According to the 28 day survival after diagnosis,the patients were divided into death group and survival group.Univariate and multivariate Logistic analysis were used to examine the risk factors of AB positive patients.Results This study included 98 patients.The 28 day mortality was 54.1％.The independent risk factors of mortality were:merge coronary heart disease(OR =38.3,95％ CI:1.81-720.10,P =0.019),high APACHE Ⅱ score (OR =3.47,95％ CI:1.30-12.81,P=0.043),prolonged APTT(OR =1.32,95％ CI:1.03-1.71,P=0.037),high levels of PCT(OR=2.78,95％ CI:1.30-7.02,P =0.023).APACHE Ⅱ scores and patients died from AB culture positive time was significantly negative correlation,r =-0.601,P =0.000.Whether the application of antibiotics for AB was not clearly affected by the prognosis.Conclusion Merge coronary heart disease,high APACHE Ⅱ score,prolonged APTT,high levels of PCT are independent risk factors for AB culture positive patients.In particular,merge coronary heart disease and the severity of the underlying disease determine the patient's prognosis.