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The application of isotope exchange can realize radiolabeling in partially aqueous media, proceed under mild reaction conditions, and exclude complex purification procedure. It is suitable for one-step labeling of sensitive biomolecules with clinical application potential. This review systematically introduces the 18F/ 19F isotope exchange reactions based on carbon and those non-carbon-based reaction centers including silicon, boron, phosphorus, sulfur, gallium and iron. Discussions of the effects on isotope exchange radiochemical yields and molar activities by different reaction types, and labeling conditions and substitute groups on classic labeled substrate are held where possible, as well as recent applications in using these methodologies to develop PET probes.
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Severe viral pneumonia in children has become an urgent public health problem in view of its high morbidity and mortality.Neutralizing antibodies, as passive immune agents, can be injected into the body so that the body can quickly obtain immunity against specific viruses and have the potential to prevent and treat severe viral pneumonia in children.This review analyzed the possible mechanisms by which neutralizing antibodies play roles in severe viral pneumonia in children, discussed the shortcomings of existing research and possible challenges, and attempted to point out the direction worthy of future research.
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Objective To assess the imaging characteristics of 18F-Alfalide II in different tumorbearing mice and pharmacokinetics in Beagle dogs.Methods BALB/c nude mice(n-24)were used for subcutaneous tumor models(A549 and U87MG),orthotopic lung cancer models(A549)and orthotopic breast cancer models(MDA-MB-231)(n=6 in each group).18F-Alfatide II and 18F-fluorodeoxyglucose(FDG)microPET/CT images were compared in the 4 types of tumor-bearing nude mice models.18F-Alfatide II blocking experiment,biodistribution experiment and imaging studies in tumors of different growth cycles were performed in A549 subcutaneous tumor-bearing nude mice models.Pharmacokinetic experiments were carried out in Beagle dogs(n = 6)and CD-1 mice(n = 9).Two-sample t test was used to analyze the data.Results Compared with 18F-FDG,18F-Alfatide II microPET/CT images showed better imaging quality and contrast in subcutaneous A549,U87MG tumors and orthotopic A549(tumor/heart:4.50±1.17 vs 0.95±0.31;t = 4.125,P<0.01),orthotopic MDA-MB-231(tumor/muscle:6.60±1.53 vs 0.92±0.43;t = 3.984,P<0.01)transplantation nude mice models.18F-Alfatide II could specifically target A549 tumors,and the tumor uptake of 18F-Alfatide II was reduced by about 75% after pre-injection with cyclo(Arg-Gly-Asp-D-Tyr-Lys)(c(RGDyk)).18F-Alfatide II was rapidly cleared from the blood of Beagle dogs(T1/2 was(57.34±11.69)min).It was cleared in the form of prototype drug and(69.24±6.82)% of cumulative dose was excreted through the urine within 4 h after administration.Conclusions 18F-Alfatide II shows a higher target/non-target ratio than,18F-FDG in the imaging of A549,MDA-MB-231 and U87MG tumor-bearing nude mice models,which is more conducive to the diagnosis of tumor.18F-Alfatide II has excellent pharmacokinetic properties.
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Objective To observe the multimodal imaging characteristics of combined hamatoma of the retina and retinal pigment epithelium (CHRRPE).Methods A retrospective case study.From January 2013 to December 2017,6 CHRRPE patients (6 eyes) diagnosed in Department of Ophthalmology,Sun Yat-sen Memorial Hospital were included in the study.There were 4 males and 2 females,with the mean age of 12.0±8.10 years.There were 5 eyes with BCVA ≤0.1,1 eye with BCVA＞ 1.0.Corneal fluoroscopy showed 1 eye with an external oblique 15°,and the remaining eye had no abnormalities in the anterior segment.All eyes underwent fundus color photography,FAF,FFA,ICGA,OCT and color Doppler flow imaging (CDFI).The multimodal imaging characteristics were observed.Results All the affected eyes CHRRPE were located in the posterior pole and showed mild elevation.Most of the retinal neuroepithelial layers had different degrees of hyperplasia,vascular tortuosity and retinal folds.Of the 6 eyes,4 eyes (66.7％) involving the macula and optic disc,only 2 eyes (33.3％) involving the macula.OCT showed that the structure of the neuroepithelial layer was unclear and the signal intensity was uneven;it involved 2 eyes of the whole retina (33.3％) and only 4 eyes of the neuroepithelial layer (66.7％).FFA and ICGA showed that the choroidal background fluorescence of the early lesions was weakened,and the lesions showed slightly weak fluorescence;the late telangiectasia fluorescein was obviously leaked,and the lesions were stained with fluorescence.FAF mainly appears as weak autofluorescence with a small amount of strong autofluorescence.CDFI has no characteristic performance.Conclusions CHRRPE is mainly a membrane-like hyperplasia without angiogenesis,involving the retinal neuroepithelial layer,and may also involve the entire retina.OCT is dominated by strong reflection;AF,FFA and ICGA are mainly weak fluorescence.
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Objective:To find out the chemical constituents in Atrichum undulatum var. gacelisetum.Methods:The compounds were isolated by silica gel and TLC, and purified by recrystallization from the ethanol extract. The structures of the compounds were elucidated by spectral analysis and physicochemical properties. Results:Six compounds were obtained and the structures were identified as dotriacontane ( 1 ), montanic acid ( 2 ), β-sitosterol ( 3 ), daucosterol ( 4 ), luteolin 7-O-D-glucoside ( 5 ) and luteolin ( 6 ). Conclusion:Compounds 1-6 are isolated from the species for the first time.
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Pathological myopia can induce choroidal neovascularization (PM-CNV).The potential risk factors include ageing,long axial length of the eyeball,thinning of subfoveal choroidal thickness,fundus atrophy spot and lacquer crack.These factors may induce atrophy of retinal pigment epithelial cells (RPE) and hypoxia,resulting in vascular endothelial growth factors (VEGF) secretion by outer retina.The lesion type,location and activity of PM-CNV can be determined by fundus fluorescein angiography.The features of PM-CNV on optical coherence tomography include strong reflective area close to RPE with very small amount of subretinal fluid (active stage),surface strong reflection with signal attenuation area (scar stage) and flat lesion and chorioretinal atrophy (atrophy stage).Photodynamic therapy and intravitreal injection of anti-VEGF drugs are major treatments for PM-CNV,the latter is more commonly used now.However,more large randomized controlled studies are required to explore the treatment regimen (such as frequency,indications for repeated or termination of treatment) and the efficacy factors further.
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A high sensitive and rapid method was developed for the analysis of lappaconitine in mouse plasma using liquid chromatography coupled to mass spectrometry (LC-MS). Detection was performed by positive ion electrospray ionization (ESI) in multiple reaction monitoring (MRM) mode, monitoring the transitions m/z 585 --> m/z 535 and m/z 356 --> m/z 192, for the quantification of lappaconitine and tetrahydropalmatine (internal standard, IS), respectively. The method was linear over the concentration range of 3.0-2000.0 ng x mL(-1). The lower limit of quantification was 3.0 ng x mL(-1). Intra- and inter-run precisions (RSD) were both less than 9.9% and accuracy (RE) within +/- 4.8%. After single intravenous injections of lappaconitine hydrobromide at 1.0, 2.0 and 4.0 mg x kg(-1), the elimination half-lives (t(1/2)) were 0.47, 0.48 and 0.49 h, and the areas under the curve (AUC(0-t)) were 55.5, 110.5 and 402.9 ng x h x mL(-1), separately. The pharmacokinetic profile of lappaconitine was linear at relatively lower dose levels (1.0-2.0 mg x kg(-1)). When the dose increased farther to 4.0 mg x kg(-1), the Vz and CL decreased, and the increase fold of the AUC was much larger than that of the dose.