BackgroundSubgroups A, B, E and J are the major subgroups of avian leukosis virus (ALV) infecting chickens. ALV infection has become endemic in China and has a significant negative effect on the poultry industry. Consequently, there is an urgent need for a specific, sensitive and rapid method for diagnosis and eradication of ALV. Therefore, we developed a simple and rapid real-time loop-mediated isothermal amplification (LAMP) reaction for the timely detection of the common ALV subgroups, whereby the amplification can be obtained in 35 min under isothermal conditions at 63 °C, ability to specific, sensitive and rapid detect all the common ALV subgroups.MethodsA set of four specific primers was designed to target the sequences of the pol gene of ALV, and the loop-mediated isothermal amplification (LAMP) assay were developed and compared with PCR and virus isolation methods.ResultsThe results from specificity of the LAMP assay showed that only target ALVs DNA was amplified. The LAMP assay demonstrated a sensitivity of 20 copies/reaction of ALV DNA, which was 10 times higher than the conventional PCR measurement. To further evaluate the reliability of the method, the assay was evaluated with ALV DNA from a panel of 81 clinical samples suspected of ALV infection. The results verify that the LAMP method was more sensitive than the conventional PCR and virus isolation method.ConclusionIn conclusion, the developed LAMP assay was a simple, inexpensive, sensitive method for the rapid detection of the most common subgroups of ALV, and it provided a useful and practical tool in the eradication program for ALV in the poultry industry.

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Objectives Dynamic contrast-enhanced MRI (DCE-MRI) with Extended Tofts Linear (ETL) model has been used in tissue and tumor evaluation. However, its reliability and reproducibility in pancreatic evaluation has been unclear. It is also unclear whether pancreatic DCE-MRI pharmacokinetic parameters were consistent and stable among different pancreatic regions, ages and genders. Methods Pancreatic pharmacokinetic parameters of 54 volunteers were calculated using DCE-MRI with ETL model. Firstly, Intra- and inter-observer reproducibility was evaluated using intra-class correlation coefficient (ICC) and coefficient of variation (CoV). Secondly, subgroup evaluation of pancreatic DCE-MRI pharmacokinetic parameters was performed. 54 subjects were divided into three groups in virtue of pancreatic region, three groups according to age, two groups according to gender, which pharmacokinetic parameters among and between different groups were calculated and compared. Results There was excellent agreement and low variability of intra- and inter-observer to pancreatic DCE-MRI pharmacokinetic parameters. The intra- and inter-observer ICCs of Ktrans, kep, ve, vp were 0.971, 0.952, 0.959, 0.944 and 0.947, 0.911, 0.978, 0.917, respectively. The intra- and inter-observer CoVs of Ktrans, kep, ve, vp were 9.98%, 5.99%, 6.47%, 4.76% and 10.15%, 5.22%, 6.28%, 5.40%, respectively. There were no significant differences of Ktrans, kep among different pancreatic regions, among different age groups, between male and female groups (P all > 0.10). Only, pancreatic ve of old group was higher than that of young and middle-aged groups (P = 0.042, 0.001), and vp of pancreatic head was higher than that of pancreatic body and tail (P = 0.014, 0.043). Conclusions DCE-MRI with ETL model is reliable and reproducible for quantitative assessment of pancreatic pharmacokinetic parameters. ve varies with age and vp varies with pancreatic region, which can provide guidance for the selection of normal reference in the pharmacokinetics study of pancreatic diseases.