Two fragments G1 and G2 of the glycoprotein G gene of bovine respiratory syncytial virus(BRSV) were selected for expression in Escherichia coli based on the analysis of glycoprotein G by DNA Star software.Then the two fragments of glycoprotein G were amplified by PCR with synthesized G gene of BRSV as the template.The amplified fragments G1 and G2 are 570bp and 308bp in length,respectively.The PCR products were cloned into pET30a vector and expressed in soluble form in E.coli after induction of cultured E.coli with IPTG.Both of the recombinant proteins G1 and G2 were purified by immobilized Ni ion affinity chromatography under native conditions.Then the purified proteins were analysed by Western blotting.The results showed that the purified recombinant protein G1 retained good antigenicity and specificity.But the purified recombinant protein G2 didn't possess biological activity.Antibodies against BRSV were detected in suspected bovine serum samples in China by using indirect ELISA and Western blotting with the purified recombinant protein G1.The purified recombinant protein G1 might be used as antigen for establishing serological methods for diagnosis of BRSV infection.And the purified recombinant protein G1 might also be used for preparing polyclonal and monoclonal antibodies for research on biological functions of glycoprotein G of BRSV.

Objective:To investigate the diagnostic accuracy of serological indicators and evaluate the diagnostic value of a new established combined serological model on identifying the minimal hepatic encephalopathy (MHE) in patients with compensated cirrhosis.Methods:This prospective multicenter study enrolled 263 compensated cirrhotic patients from 23 hospitals in 15 provinces, autonomous regions and municipalities of China between October 2021 and August 2022. Clinical data and laboratory test results were collected, and the model for end-stage liver disease (MELD) score was calculated. Ammonia level was corrected to the upper limit of normal (AMM-ULN) by the baseline blood ammonia measurements/upper limit of the normal reference value. MHE was diagnosed by combined abnormal number connection test-A and abnormal digit symbol test as suggested by Guidelines on the management of hepatic encephalopathy in cirrhosis. The patients were randomly divided (7∶3) into training set ( n=185) and validation set ( n=78) based on caret package of R language. Logistic regression was used to establish a combined model of MHE diagnosis. The diagnostic performance was evaluated by the area under the curve (AUC) of receiver operating characteristic curve, Hosmer-Lemeshow test and calibration curve. The internal verification was carried out by the Bootstrap method ( n=200). AUC comparisons were achieved using the Delong test. Results:In the training set, prevalence of MHE was 37.8% (70/185). There were statistically significant differences in AMM-ULN, albumin, platelet, alkaline phosphatase, international normalized ratio, MELD score and education between non-MHE group and MHE group (all P<0.05). Multivariate Logistic regression analysis showed that AMM-ULN [odds ratio ( OR)=1.78, 95% confidence interval ( CI) 1.05-3.14, P=0.038] and MELD score ( OR=1.11, 95% CI 1.04-1.20, P=0.002) were independent risk factors for MHE, and the AUC for predicting MHE were 0.663, 0.625, respectively. Compared with the use of blood AMM-ULN and MELD score alone, the AUC of the combined model of AMM-ULN, MELD score and education exhibited better predictive performance in determining the presence of MHE was 0.755, the specificity and sensitivity was 85.2% and 55.7%, respectively. Hosmer-Lemeshow test and calibration curve showed that the model had good calibration ( P=0.733). The AUC for internal validation of the combined model for diagnosing MHE was 0.752. In the validation set, the AUC of the combined model for diagnosing MHE was 0.794, and Hosmer-Lemeshow test showed good calibration ( P=0.841). Conclusion:Use of the combined model including AMM-ULN, MELD score and education could improve the predictive efficiency of MHE among patients with compensated cirrhosis.

Objective:To investigate the diagnostic value of independent and combined subtests of the psychometric hepatic encephalopathy score (PHES) in mild hepatic encephalopathy(MHE) of patients with liver cirrhosis, so as to optimize the PHES.Methods:This was a prospective, multicenter and real-world study which was sponsored by the National Clinical Research Center of Infectious Diseases and the Portal Hypertension Consortium. Twenty-six hospitals from 13 provinces, autonomous regions and municipalities countrywide participated in this study, induding Tianjin Third Central Hospital, the Fourth People′s Hospital of Qinghai Province, the Second Affiliated Hospital of Baotou Medical College, the Third People′s Hospital of Taiyuan, the Fifth Medical Center of PLA General Hospital and so on. From October 2021 to February 2022, outpatients and hospitalized patients with liver cirrhosis and no obvious hepatic encephalopathy were consecutively enrolled. All patients received 5 PHES subjects in the same order: number connection test(NCT)-A, NCT-B, digit symbol test(DST), line tracing test(LTT) and serial dotting test(SDT), and the scores were calculated. The total score of PHES <-4 was taken as the cut-off value for diagnosing MHE. Compare the differences in each subtest between MHE group and non-MHE group. Receiver operating characteristic curve(ROC) and area under the curve(AUC) was performed to assess the diagnostic value of independent and combined subtests in MHE. Mann-Whitney U test and DeLong test were used for statistical analysis. Results:A total of 581 patients with liver cirrhosis were enrolled, 457 were diagnosed as MHE, and the incidence of MHE was 78.7%. The results of NCT-A, NCT-B, SDT, LTT, DST of MHE group were 60.00 s(47.01 s, 88.00 s), 90.45 s(69.32 s, 125.35 s), 74.00 s(57.65 s, 96.60 s), 74.72(60.00, 98.61) and 27.00(20.00, 36.00), respectively. Compared those of non-MHE group(34.00 s(29.15 s, 44.48 s), 50.00 s(40.98 s, 60.77 s), 50.00 s(41.07 s, 63.03 s), 46.23(38.55, 59.42) and 42.00(34.00, 50.75)), the differences were statistically significant( Z=12.37, 12.98, 9.83, 11.56, 10.66; all P<0.001). The AUC(95% confidence interval(95% CI)) of subtests of PHES NCT-B, NCT-A, LTT, DST and SDT alone in MHE diagnosis were 0.880(0.849 to 0.910), 0.862(0.828 to 0.896), 0.838(0.799 to 0.877), 0.812(0.772 to 0.851) and 0.788(0.743 to 0.832), respectively. The combination of 2 PHES subtests significantly increased the diagnostic efficacy. Among them the diagnostic efficacy of the combination of NCT-B and LTT was the best, the AUC(95% CI) was 0.924(0.902 to 0.947), the specificity was 91.9% and the sensitivity was 79.2%, which was better than a single PHES subtest (NCT-A, NCT-B, SDT, LTT and DST) and the combination of NCT-A and DST(AUC was 0.879, 95% CI0.847 to 0.910) which was recommended by guidelines on the management of hepatic encephalopathy in cirrhosis, the differences were statistically significant ( Z=3.78, 3.83, 5.57, 5.51, 5.38, 2.93; all P<0.01). Furthermore, compared between the combination of NCT-B and LTT and the combination of 3 subests of PHES, only the diagnostic efficacy of combination of NCT-B, LTT and SDT (AUC was 0.936, 95% CI 0.916 to 0.956) was better than that of the combination of NCT-B and LTT, the difference was statistically significant( Z=2.32, P=0.020). Conclusion:Based on the diagnostic efficacy and clinical feasibility of PHES subtests and their combinations, the combination of NCT-B and LTT is recommended for the diagnosis of MHE.