OBJECTIVE:To establish a method for the content determination of AV45(the labeled precursor of PET agent for Aβ plaques)and its related substances. METHODS:HPLC method was performed on the column of Inertsil C18 with mobile phase of 50 mmol/L Disodium hydrogen phosphate solution- acetonitrile(containing 0.01% triethylamine)(15∶85,V/V)at a flow rate of 1.0 ml/min,the detection wavelength was 325 nm,and column temperature was 30 ℃,and volume injection was 20 μl. RESULTS:The AV45 and reaction intermediate as well as individual impurity peaks were well separated;the linear range was 200-1 000 μg/ml for AV45(r=0.999 2)and 20-100 μg/ml for intermediate(r=0.999 6);the detection limit and quantification limit of reaction in-termediate AV45 were 0.1 ng and 0.5 ng,respectively;RSDs of precision,stability and reproducibility tests were lower than 0.5%;recovery of AV45 was 98.93%-101.58%(RSD=0.69%,n=9). CONCLUSIONS:The method is simple and accurate with high specificity and good reproducibility,and suitable for content determination of AV45(the labeled precursor of PET agent for Aβplaques)and its related substances.

The definition and function of epidemiological investigation report on food safety accident is described and its impact on the business behavior,civil liability,administrative responsibility,and criminal responsibility of food producers,marketers,supervisory and management department is presented.It suggests that center for disease prevention and control should give attention to timeliness,authenticity,accuracy,normalization of epidemiological investigation report on food safety accidents and cases.The purpose is to avoid accountability on investigation of food safety accidents and ensure the epidemiological investigation report not been challenged in legal proceedings as evidence.

Objective:To construct a rat model of hypothalamic obesity by two point electrical damage to the ventromedial hypothalamus and arcuate nucleus.Methods:Twenty adult male SD rats of SPF grade were randomly divided into experimental group and sham operation group.A 25GA (0.45 mm) solid iron needle was used, the needle was coated with an insulating layer, and the tip exposed a 0.5 mm conductive area.With reference to The Rat Brain in Stereotaxic Coordinates and using the stereotactic instrument (AP: -2.6 mm, ML: ± 0.6 mm, DV: -9.6 mm) as the coordinate, 1.5 mA current was continuously applied for 25 s, the ventromedial nucleus (VMH) and arcuate nucleus (ARC) of bilateral brain in SD rats was damaged.During the experiment, the body weight(BW), food intake(FI) and water intake(WI) of the two groups were recorded regularly.The rats were sacrificed on the 28th day after the operation, and the changes of periprenal fat mass and body length were measured.The changes of liver and adipose tissue were detected by HE staining method, leptin by ELISA, leptin receptor(LEPR) by Western blot.Results:(1) The body weight of rats in the experimental group ((427.5±17.7)g) and weight gain ((208.5±14.8)g) were significantly increased compared with the rats in the control group((349.2±17.7)g), ((136.2±21.4)g)on the 28th day after operation ( t=7.661, 6.806, both P<0.001). (2) The daily food intake of rats in the experimental group ((44.2±6.6)g) on the 28th day after surgery was significantly higher than that in the control group ((23.0±3.6)g) ( t=6.918, P<0.001). There was no significant difference of the daily drinking water of rats between experimental group((37.5±12.1)ml) and the control group ((35.0±11.8)ml) ( t=0.361, P=0.726). (3) Perikidney fat mass of experimental group rats ((13.4±2.7)g) significantly increased 28 days after operation compared with control group rats((6.3±0.9)g)( t=4.250, P<0.05). The naso-anal length of experimental group((21.8±0.4)cm) was significantly decreased compared with the control group ((23.4±0.2)cm) ( t=-6.788, P<0.01). The Lee index of the experimental group (348.9±8.5) was significantly higher than that of the control group(305.5±4.3)( t=7.898, P<0.01). (4) The serum leptin content ((8 324.10±159.00)μg/L) of the experimental group rats at 28 days after surgery was significantly higher than that of the control group((2 705.31±407.10)μg/L) ( t=25.712, P<0.001). The lateral hypothalamus area (LHA) LEPR protein expression (1.3±0.1) in the experimental group was significantly higher than that in the control group (0.9±0.1) ( t=4.932, P<0.01). Conclusion:Two-point electrical damage to bilateral VMH and ARC of rats can establish hypothalamic obese rat model.