In order to achieve rapid detection of duck hepatitis A virus type 3(DHAV-3),this ex-periment initially performed prokaryotic expression of the non-structural protein 3D of DHAV-3,followed by immunization of BALB/c mice with the purified protein.After immunization,mouse spleen cells were fused with myeloma cells(SP2/0)to prepare monoclonal antibodies.Subsequent-ly,a double-antibody sandwich ELISA(DAS-ELISA)detection method was established using the monoclonal antibodies,and its sensitivity,specificity,and repeatability were evaluated.Finally,the established method was applied to the detection of clinical samples and validated for compliance with the RT-PCR method.The results showed that the DHAV-3 3D protein was efficiently ex-pressed in BL21(DE3),and its specificity was confirmed by Western blot after purification.After cell fusion and three rounds of subcloning,six hybridoma cells were successfully screened and named 1A3,1B6,1C7,1D9,2A1,and 3A9.The subtype identification of the antibodies showed that 1A3 belonged to IgG2b,1B6 belonged to IgG2a,3A9 belonged to IgG3,and 1C7,1D9,and 2A1 be-longed to IgG1.After screening,the high-affinity monoclonal antibodies 1B6 and 1 A3 were selected as the capture antibody and detection antibody,respectively,and use to establish the DAS-ELISA detection method.After optimizing the reaction conditions,the optimal coating concentration of the capture antibody 1B6 was determined to be 1×10-3 g/L,and the optimal dilution of the detection antibody 1A3 was 1∶1 000.The cut-off value was established as 0.256.The sensitivity test showed that the method had a minimum detection limit of 4.0 ×10-4 g/L for the 3D protein.The repeat-ability test showed that the within-batch and between-batch coefficients of variation were both less than 9％,indicating good repeatability.The specificity test showed that the method did not show specific reactions with duck adenovirus(DAdV),muscovy duck parvovirus(MDPV),duck circo-virus(DuCV),duck plague virus(DPV),duck reovirus(DRV),or Riemerella anatipestifer(RA),but cross-reacted with Duck hepatitis a virus type 1(DHAV-1),allowing simultaneous de-tection of DHAV-3 and DHAV-1 pathogens.The DAS-ELISA method established in this experi-ment was compared with the RT-PCR method for the detection of 186 clinical samples,and the DAS-ELISA method could simultaneously identify DHAV-1 and DHAV-3,with a compliance rate of 98.9％compared to the RT-PCR method.In conclusion,the established DAS-ELISA method showed good repeatability and high sensitivity,and can be used for the diagnosis of DHAV-1 and DHAV-3,providing technical support for the epidemiological investigation and prevention of Duck Hepatitis A.

In order to achieve rapid detection of duck hepatitis A virus type 3(DHAV-3),this ex-periment initially performed prokaryotic expression of the non-structural protein 3D of DHAV-3,followed by immunization of BALB/c mice with the purified protein.After immunization,mouse spleen cells were fused with myeloma cells(SP2/0)to prepare monoclonal antibodies.Subsequent-ly,a double-antibody sandwich ELISA(DAS-ELISA)detection method was established using the monoclonal antibodies,and its sensitivity,specificity,and repeatability were evaluated.Finally,the established method was applied to the detection of clinical samples and validated for compliance with the RT-PCR method.The results showed that the DHAV-3 3D protein was efficiently ex-pressed in BL21(DE3),and its specificity was confirmed by Western blot after purification.After cell fusion and three rounds of subcloning,six hybridoma cells were successfully screened and named 1A3,1B6,1C7,1D9,2A1,and 3A9.The subtype identification of the antibodies showed that 1A3 belonged to IgG2b,1B6 belonged to IgG2a,3A9 belonged to IgG3,and 1C7,1D9,and 2A1 be-longed to IgG1.After screening,the high-affinity monoclonal antibodies 1B6 and 1 A3 were selected as the capture antibody and detection antibody,respectively,and use to establish the DAS-ELISA detection method.After optimizing the reaction conditions,the optimal coating concentration of the capture antibody 1B6 was determined to be 1×10-3 g/L,and the optimal dilution of the detection antibody 1A3 was 1∶1 000.The cut-off value was established as 0.256.The sensitivity test showed that the method had a minimum detection limit of 4.0 ×10-4 g/L for the 3D protein.The repeat-ability test showed that the within-batch and between-batch coefficients of variation were both less than 9％,indicating good repeatability.The specificity test showed that the method did not show specific reactions with duck adenovirus(DAdV),muscovy duck parvovirus(MDPV),duck circo-virus(DuCV),duck plague virus(DPV),duck reovirus(DRV),or Riemerella anatipestifer(RA),but cross-reacted with Duck hepatitis a virus type 1(DHAV-1),allowing simultaneous de-tection of DHAV-3 and DHAV-1 pathogens.The DAS-ELISA method established in this experi-ment was compared with the RT-PCR method for the detection of 186 clinical samples,and the DAS-ELISA method could simultaneously identify DHAV-1 and DHAV-3,with a compliance rate of 98.9％compared to the RT-PCR method.In conclusion,the established DAS-ELISA method showed good repeatability and high sensitivity,and can be used for the diagnosis of DHAV-1 and DHAV-3,providing technical support for the epidemiological investigation and prevention of Duck Hepatitis A.

Objective To explore the relationship between the establishment of collateral circulation caused by iliac vein compression syndrom(IVCS) and the deep venous thrombosis (DVT). Methods Different types of ideal collateral circulation models and IVCS patient-specific models were numerically simulated using computational fluid dynamics (CFD) in combination with the blood stasis model. The relationship between blood retention and collateral types and cross-sectional area was studied, and the relationship with thrombosis was explored. Results Wall shear stress (WSS) at the distal end part of each ideal model was 0.3 Pa. After four cardiac cycles, the residual blood stayed at the stenosis and the distal end part for the lumbar ascending and pelvic type models, the old blood volume fraction (OBVF) varied with collateral cross-sectional areas, ranging from 5%-90% and 70%-80%, respectively. The OBVF of the coexistence model was above 80%. The WSS at the distal end part of the patient-specific model was 0.9 Pa, and the OBVF at the distal end part was 51.5%. Conclusions The stenosis and the distal end part are most prone to blood stasis, and closely related with DVT. The larger the collateral cross-sectional area, the more serious the blood stagnation. Blood stagnation of the coexistence model is higher compared with the model with lumbar ascending type and pelvic type.

The aim of this study was to synthesize and evaluate the necrosis avidity of MRI contrast agent based on rhein and linked by ether. The novel ligand 10-{［6-(1, 8-dihydroxyanthraquinone-3-carboxamido)ethoxyethyl］amino}carbonylmethyl-1, 4, 7, 10-tetraazacyclododecan-1, 4, 7-triacetic acid(DO3A-Ether-Rhein, E1)was synthesized by two steps of acylation and deprotection reaction. The paramagnetic gadolinium 10-{［6-(1, 8-dihydroxyanthraquinone-3-carboxamido)ethoxyethyl］amino}carbonylmethyl-1, 4, 7, 10-tetraazacyclododecan-1, 4, 7-triacetic acid(Gd-DO3A-Ether-Rhein, GdE1)was obtained by coordination of Gd3+ with the above ligand. We examined the necrotic avidity of GdE1 in human hepatocellular carcinoma HepG2 cell necrosis induced by hyperthermia in vitro and in rat model with muscular necrosis induced by microwave ablation in vivo by MRI. The MRI was implemented before administration of GdE1 and during 0-9 h after administration of GdE1(0. 1 mmol/kg), and Gd-DOTA(gadolinium 1, 4, 7, 10-tetraacetic acid-1, 4, 7, 10-tetraazacyclo dodecane)was used as control. The signal intensity of necrotic cells(4 369±70)was significantly higher than that of normal cells(2 555±84)(P< 0. 05). Similarly, the contrast ratio between necrotic and normal muscle at 3 h after administration of GdE1(2. 00±0. 12)was remarkblely higher than that at 0 h after administration of GdE1(1. 27±0. 03)(P< 0. 05). Therefore, GdE1 presents good necrosis affinity and has the potential to be used in the diagnosis of necrosis-related diseases.