This study investigates the feasibility of the VP8*protein as a subunit vaccine target for porcine rotavirus A(PoRVA),a major causative agent of diarrhea in piglets.The VP8* genes of PoRVA P[13]and P[23]genotype strains were amplified by RT-PCR.These genes were then liga-ted into the pET-28a(+)vector,yielding recombinant plasmids pET-28a-XJWF1-VP8*-P[23]and pET-28a-ShXYW13-VP8*-P[13].These plasmids were subsequently transformed into BL21(DE3)competent cells.The VP8*protein,induced by IPTG,was purified using affinity chroma-tography,and its expression and purification were verified by SDS-PAGE and Western blot.The purified VP8* protein was used to immunize mice,and serum samples were collected after three immunizations.Cross-neutralization assays were conducted to evaluate the ability of the VP8*protein immune serum to neutralize different genotype strains.The results demonstrated the ex-pression of soluble VP8*protein,with SDS-PAGE and Western blot analyses showing that the purified VP8*protein existed in both monomeric(27 kDa)and homodimeric(54 kDa)forms.ELISA results indicated that high levels of antibodies were produced in mice immunized with VP 8*-P[13]and VP8*-P[23]after three immunizations.Serum cross-neutralization assays revealed that the neutralizing titers of PoRVA VP8*-P[13]and VP8*-P[23]immune sera against homol-ogous genotype strains ranged from 1∶4 800 to 1∶19 200,significantly higher than those against heterologous genotype strains(1∶1 200).This suggests that the VP8*protein of different geno-type strains exhibits both antigenic conservation and distinct variability.The data obtained in this study provide a solid foundation for further exploration of the antigenic structure of the PoRVA VP8* protein and the development of novel subunit vaccines.

This study investigates the feasibility of the VP8*protein as a subunit vaccine target for porcine rotavirus A(PoRVA),a major causative agent of diarrhea in piglets.The VP8* genes of PoRVA P[13]and P[23]genotype strains were amplified by RT-PCR.These genes were then liga-ted into the pET-28a(+)vector,yielding recombinant plasmids pET-28a-XJWF1-VP8*-P[23]and pET-28a-ShXYW13-VP8*-P[13].These plasmids were subsequently transformed into BL21(DE3)competent cells.The VP8*protein,induced by IPTG,was purified using affinity chroma-tography,and its expression and purification were verified by SDS-PAGE and Western blot.The purified VP8* protein was used to immunize mice,and serum samples were collected after three immunizations.Cross-neutralization assays were conducted to evaluate the ability of the VP8*protein immune serum to neutralize different genotype strains.The results demonstrated the ex-pression of soluble VP8*protein,with SDS-PAGE and Western blot analyses showing that the purified VP8*protein existed in both monomeric(27 kDa)and homodimeric(54 kDa)forms.ELISA results indicated that high levels of antibodies were produced in mice immunized with VP 8*-P[13]and VP8*-P[23]after three immunizations.Serum cross-neutralization assays revealed that the neutralizing titers of PoRVA VP8*-P[13]and VP8*-P[23]immune sera against homol-ogous genotype strains ranged from 1∶4 800 to 1∶19 200,significantly higher than those against heterologous genotype strains(1∶1 200).This suggests that the VP8*protein of different geno-type strains exhibits both antigenic conservation and distinct variability.The data obtained in this study provide a solid foundation for further exploration of the antigenic structure of the PoRVA VP8* protein and the development of novel subunit vaccines.

Objective To investigate the efficacy and safety of vasopressin receptor antagonist tolvaptan for treating dilutional hyponatremia casused by decompensated liver cirrhosis.Methods Ninety-six subjects with decompensated liver cirrhosis complicated by dilutional hyponatremia were divided into test group (n =56) and control group (n =40) by double blind method.Test group were treated with a single dose of tolvaptan 15 mg orally in addition to routine therapy,while control group were treated with routine therapy plus placebo.The changes in serum sodium concentration,liver functions,ascites,and edema of lower extremities between the two groups were observed.Measurement data were compared by t test,and categorical data were compared by chisquare test.Results On day 7,36 (64.3％) patients in test group and 9 (22.5％) patients in control group reached normal serum sodium concentrations (x2 =5.241,P＜0.01).All the patients in test group and only 3 patients in control group had 24 hours' total urine volume above 3500 mL.Difference of 24 hours' total urine volume during 7-day treatment between the two groups was statistically significant (t=20.899,P＜0.01).Thirty-nine patients in test group and 15 patients in control group had reduced ascites (x2 =4.260,P=0.039),but improvement of edema in lower extremities of both groups was comparable (12 cases in test group and 7 cases in control group; x2 =0.227,P=0.634).Serum alanine aminotransferase (ALT),total bilirubin (TBil),potassium and creatinine levels of test group were improved after treatment,but were not significantly different from either baseline levels (t=1.509,0.783,1.107,1.237; both P＞0.05) or those of the control group (t=1.712,1.635,1.121,0.873; both P＞0.05).Conclusions Single dose of tolvaptan (15 mg) exerts a strong diuretic effect and is able to greatly increase serum sodium concentration,thus has distinct therapeutic effect for patients with decompensated liver cirrhosis complicated by dilutional hyponatremia.